In December 2020, the population of Eluru town experienced an epidemic in which 600 people reported multiple neurological problems over two weeks.
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Early in December 2020, the population of Eluru town in Andhra Pradesh experienced an epidemic that can only be described as bizarre. More than 600 people reported a range of neurological problems over two weeks. The epidemic ended as quickly as the epidemic began, by the middle of the month.
The dominant symptom was convulsions but also included loss of consciousness, fainting, drowsiness, nausea and vomiting, and head and limb injuries resulting from the convulsions and loss of consciousness. Some 300 people were admitted to local hospitals for treatment.
The media dubbed the cause a ‘mystery illness’, and various theories of its origins floated around.
The Andhra Pradesh government quickly swung into action and about 13 agencies, including government research institutions and private medical colleges, were assembled to investigate the epidemic. The investigations included clinical examinations, tests of water, food, air, soil and human and animal body fluids, for a range of neurotoxicants, including chemical and biological agents.
The government concluded that toxins were the cause of the outbreak, with pesticides in food or water being the most likely culprits. Some experts debated the specific pesticide that may have caused the observed illness, but even after a year, there has been no definitive evidence regarding the cause.
This being the case, some important questions still remain to be answered.
1. Was the observed illness real?
Neurologists I spoke to who treated people with the illness stated unequivocally that the convulsions were real and not mass hysteria or pseudo-seizures (or psychogenic non-epileptic seizures). Their testimony was compelling.
2.How did the toxins get into the body?
To cause illness in a wide spectrum of men, women and children, the toxins needed to be from a source common to the population. This would be from water, food or air. Since the population couldn’t all be eating the same food, and no known air pollutants cause convulsions, the likely source was water.
There are multiple anecdotal reports that the drinking water quality in the Eluru town area began deteriorating about 10 days prior to the onset of convulsions. Residents reported that the water had turned greenish-brown and emitted a bad odour, and speculated that water in the sewage and drinking-water lines could have got mixed up. They also reported that the water quality had substantially improved since the convulsion event.
Thus, the possibility that water channels were inundated by heavy rainfall from Cyclone Nivar, combined with the possibility of broken drinking-water pipes and the lack of a sewage treatment plant in Eluru, may have been important factors leading to the contamination of the town’s drinking water supply.
3. What is the probable toxin and its mechanism of action?
In November 2021, new information emerged on the epidemic. Researchers from the National Institute of Nutrition, Hyderabad, published a paper identifying triazophos, an organophosphate pesticide used for insect control, as a probable cause for the epidemic of serious neurological problems experienced by the Eluru population.
Triazophos was found in household drinking water and in the blood and urine samples of affected victims. It is efficiently absorbed by ingestion and belongs to a class of organophosphate pesticides that are well-known neurotoxins. The possibility of a mixture of chemicals interacting to enhance the neurotoxic effect must also be seriously considered. It is clear that very high concentrations of this chemical must have been present in the water to lower the seizure threshold and cause convulsions.
The inference is that contamination most likely occurred close enough to the household drinking-water supply to yield these high concentrations.
The epidemic, however, also throws up the larger question of how and why pesticides found their way into the water supply. A forensic investigation is needed to examine the source(s) and method(s) by which the pesticides could have found their way into the drinking-water supply in the area, and whether the cause was negligence or an accident. Such an exercise is vital to determine the cause of the incident, to compensate the victims, to identify those accountable and to prevent future occurrence of such episodes.
A household survey of water-use could aid a thorough exposure assessment of the affected population and is vital to determine the contaminant source and quantity of exposure to the pesticide. Such an assessment will help establish a follow-up population study to determine long-term health effects of the poisoning in the population.
4. What measures can be taken to prevent such an illness?
Eluru township’s drinking-water systems are over a hundred years old. There is open sewage visible all over the town and which drains into nearby rural areas and likely contaminates agricultural land. The drinking water and sewage systems are in urgent need of an overhaul.
India has long been known for its high production and use of pesticides in the agricultural sector. A comprehensive environmental survey of the region’s water, food, and air should be undertaken to determine the extent of pollution from industrial, agricultural and other sources. This will also throw light on whether subsequent minor outbreaks of the illness in adjacent rural areas could have been due to environmental causes.
The nearby Kolleru Lake is among the largest freshwater lakes in India and its ecology and biodiversity need to be protected from further pollution.
This epidemic of mass convulsions is unprecedented in the world, and only thorough and tough public health measures can protect the people and the environment from the untoward effects of environmental degradation.
V. Ramana Dhara is an occupational and environmental medicine physician and a former member of the International Medical Commission on Bhopal.
While some amount of metals in drinking water is normal and even required, if the level goes beyond the set limits it can lead to a range of diseases.
New Delhi: India’s rivers have a heavy metal contamination problem. According to The Hindu, samples taken from two-thirds of water quality stations on major rivers revealed the presence of a heavy metal (or in some cases more than one) beyond limits specified by the Bureau of Indian Standards.
The Central Water Commission (CWC) collected a total of 442 surface water samples, of which 287 were polluted by heavy metals. “Samples from 101 stations had contamination by two metals, [and] six stations saw contamination by three metals,” the newspaper reported.
The most common heavy metal found was iron, and above safe limits in 156 samples. Lead, nickel, chromium, cadmium and copper were the other metals.
“Over the last few decades, the concentration of these heavy metals in river water and sediments has increased rapidly,” the CWC said in a report. It suggested increased monitoring of these levels. It has held “population growth and rise in agricultural and industrial activities” responsible for the contamination.
While some amount of metals in drinking water is normal and even required, if the level goes beyond the set limits it can lead to a range of diseases.
Long-term exposure can lead to “progressing physical, muscular, and neurological degenerative processes that mimic Alzheimer’s disease, Parkinson’s disease, muscular dystrophy and multiple sclerosis,” The Hindu reported.
The CWC study covered 67 rivers in 20 river basins, and across three seasons.
“Arsenic and zinc are the two toxic metals whose concentration was always obtained within the limits throughout the study period,” the CWC report says.
For other metals, contamination levels changes with the season. “For instance, iron contamination was persistent through most of the Ganga during monsoon but dipped significantly during the non-monsoon periods,” The Hindu noted.
Doctors and activists found a higher than normal incidence of tuberculosis, mental illnesses and arthritis-like joint pains, even among people below the age of 30.
Doctors and activists found a higher than normal incidence of tuberculosis, mental illnesses and arthritis-like joint pains, even among people below the age of 30.
The production of tendu leaves in Raigarh has fallen drastically due to coal mining, according to a farmer in the district. Credit: indiawaterportal/Flickr, CC BY-NC-SA 2.0
Tired, ghoulish bodies moving around in a field of ash casting a blanket of sameness against vast, black mines, broken now and then by the bright yellow of scorching fires – this is what a coal mine looks like. Lighting up the nation comes at a steep price for communities living near these mines and the coal-fired power plants that generate electricity. Aside from having their air severely polluted,, these people also suffer from hair loss, allergies, arthritis and mental illnesses, according to a new study that surveyed households in several villages near coal mines and plants in Chhattisgarh.
The ill effects of coal mining are not unknown. A 2013 report used air pollution data near about a 100 coal plants across the nation, representing a total power capacity of about 120 GW, and estimated that these installations were responsible for the deaths of about 100,000 people in 2011 alone, as well as more than 20 million asthma cases.
Coal mines are notorious for polluting everything around them. The Jharia mines in Jharkhand are a poster child for the terrible impacts this source of energy has on a country’s people and environment. Although this mine is the most productive and possesses better than average quality of coal compared to other mines in India, the resulting pollution has devastated the region. Fires have also been burning continuously in the mines for almost a century, scorching the earth and releasing carcinogenic gases into the atmosphere. Respiratory diseases have added to the death toll of accidents in the mines. The mines’ run-offs and coal washings have muddied the Damodar river.
The region stretching from Raniganj in West Bengal, to most of Jharkhand and into northern Chhattisgarh, together with parts of eastern Maharashtra, has the country’s largest coal reserves. It supports numerous mines and thermal power plants, allowing India to be one of the top five coal-producing countries in the world. On the flip side, the communities living near the mines and power plants are among the most devastated in turn.
Raigarh in Chhattisgarh has been home to several plants and coal mines, all but one of which are privately operated, for almost two decades. The people in the surrounding villages have been living here for much longer than that, farming and raising livestock. Since the mines and plants were set up, they have lost agricultural land and the surrounding forests, which had been another source of sustenance for the villagers. They have been organising protests and writing numerous letters to officials, all falling on deaf ears.
“The [2013] study came through a community demand,” says Rinchin, an environmentalist and one of the authors. “One was to highlight what is happening” and another another to highlight the fact that not enough attention was being paid to the people’s problems. In 2013-2014, people from Sarasmal and Kosampalli villages monitored the air pollution with the help of some NGOs and were startled by their findings. Water levels in the rivers and ponds had fallen; they found that fly ash was forming a layer on everything it could land on, from treetops to rooftops. So there was a need to document what the villagers were seeing using scientific methods, according to Rinchin.
Long-term residents of Sarasmal, Kosampalli and Dongamouha in Raigarh – 515 people (including children) – were asked about their respiratory, musculoskeletal, neurological and gastrointestinal conditions. The cohort excluded miners, plant workers and migrants. About 200 attended a medical check-up by doctors to evaluate their complaints further. All these people lived within 2 km of the mines and plants.
Soil, air and water samples were obtained and analysed from these villages. Most villagers depend on underground water sources such as tube wells and borewells for drinking water, and ponds and streams for bathing, washing and for animals.
Air samples showed high levels of arsenic, lead, nickel, manganese and silicon – higher than the permissible limit specified by Indian standards. They also showed excessive quantities of gases like NOx and carbon monoxide. The soil and water samples were equally pathetic.
However, an independent source, speaking on condition of anonymity, said coal mining does not always produce heavy metals: “These minerals can only be spread by mining if they were already first present in the soil” (paraphrased for clarity).
Many of these metals are either suspected or known to be carcinogens and contribute to a host of other illnesses like high blood-pressure, kidney damage, chronic respiratory issues and mental illnesses.
This was borne out by the health survey. Only a little more than 10% of those surveyed didn’t report any issues, regardless of how well-off they were or weren’t. The remaining 89%+ complained of several health problems, with family members showing similar symptoms. Dry cough, breathing difficulties, heavy hair loss and itchy eyes were common. Skin issues like discolouration, deeply chapped feet (even in young children), itchy skin and rashes were very common. Women experienced chronic complaints more than men. Several people reported that they had also developed these various symptoms within a year of each other.
“We have [also] found a couple of things we initially did not expect,” says Manan Ganguli, a medical doctor who was part of the study. A large proportion complained of joint pains and arthritis-like symptoms. Remarkably, people younger than 30 years, about one third of the surveyed population, reported these symptoms. This is worrying because such afflictions generally only show up in old age in healthy populations.
Another such striking result was the prevalence of mental illnesses. About 12% reported depression and anxiety, confirmed by a psychiatrist on the team. Ganguli says this proportion is more than what one would see on average in a population and is something that requires further investigation.
The bad news doesn’t end there. In Sarasmal, there were 12 tuberculosis cases among 341 villagers surveyed. Ganguli is not sure if there is a link between TB and the pollution. “We looked into it but it requires further” study, according to him – though that didn’t prevent him from speculating. There has been some evidence linking TB and air pollution. It’s possible that, given the various ailments prevalent in the area, the villagers’ immunity has been compromised, leaving them more susceptible to TB, he said.
Every step of the power-production process – mining, washing, transport and burning – hurts the people who make it possible. The Raigarh survey has only shown that these also include people living in the vicinity of these activities. Their suffering subsidises the privilege of those who consume that power. Rinchin says that, in all the government clearances required to commence mining and firing, there is an environmental component but never a health component.
A different official, who also wished to remain unnamed, remained optimistic and said, “Coal mining nowadays is absolutely safe if done scientifically.” For example, the fly ash can be used for making bricks or refilling the mine instead of dumping it as topsoil – but this should be done in a way that does not pollute groundwater. Modern thermal power plants also use other technologies that prevent the release of smoke and are considered environmentally safe.
Rinchin isn’t convinced. There needs to be an alternative even if you can say mines and power plants can be operated safely, she says. In other words, we need to rethink how much energy we need and what the alternatives to coal are.
While many countries have been trying to phase coal out, India has been commissioning more mines and more thermal power plants. At the same time, the Centre hasn’t been doing much to mitigate the health hazards either. They need to come down strictly on companies that violate environmental laws and make it more difficult to get clearances.
Lakshmi Supriya is a freelance science writer based in Bengaluru.
New Delhi: A new study has pointed out that flooding in polluted rivers has the potential to make groundwater unsafe for human use.
In December 2015, when Chennai was flooded and people were marooned, a team of scientists from Anna University was collecting groundwater samples along the Adyar river to investigate if the groundwater in this region was fit for human consumption.
Researchers collected water samples from 17 locations in December 2015 and April 2016 (i.e. during and after the floods). They tested the samples for salt and heavy-metal concentrations, the microbial load and their susceptibility to available antibiotics.
“We wanted to know if the city water met water quality parameters laid down by the Bureau of Indian Standards during and post-flood,” Lakshmanan Elango, a professor at the department of geology at Anna University and the leader of this study, told India Science Wire.
The results showed that the heavy-metal concentration and microbial load in groundwater samples were high. The samples contained microbes such as Enterobacter, Staphylococcus, Escherichia, Streptococcus, Vibrio and Salmonella – known to cause infections like dysentery, cholera and typhoid in humans. These microbes were cultured with various antibiotics used in clinical practice to treat life-threatening infections, to find out if they were susceptible or resistant to drugs.
“The bacteria were sensitive to most antibiotics but some were resistant to nalidixic acid, which is alarming as antibiotic resistance can rapidly spread in the environment,” Elango said. Nalidixic acid is a synthetic antibiotic used to inhibit the growth of, or kill off, gram-negative bacteria. The results of the study were published in the journal Scientific Data on October 10, 2017.
Additionally, scientists found a high level genetic similarities between bacteria from various locations, implying that they must have originated from a single domestic sewage source containing faecal matter. “Sewage must have washed off with flood water, which in turn inundates the wells that would have resulted in contaminating the groundwater,” Elango explained.
“Our findings show that floods have the potential to impact the microbial quality of groundwater in affected areas. Based on our study, we advise that wells must be chlorinated and the public must be warned to avoid consuming groundwater for drinking, at least for some months post floods.”
The study was conducted together with the University of Zululand in South Africa and the National University of Singapore, and was funded by India’s Department of Science and Technology.
This article was originally published by India Science Wire.
Two neutron stars collided in space, unleashing a deadly beam of gamma rays, spewing heavy metals into the cosmos and drawing the attention of over 70 observatories worldwide. The universe doesn’t get more breathtaking.
Two neutron stars collided in space, unleashing a deadly beam of gamma rays, spewing heavy metals into the cosmos and drawing the attention of over 70 observatories worldwide. The universe doesn’t get more breathtaking.
An artist’s concept of what a neutron star collision would look like. Credit: Illustration by Robin Dienel courtesy of the Carnegie Institution for Science
Sandhya Ramesh is a science writer focusing on astronomy and earth science.
Astrophysicists today have released no less than seven papers on one of the biggest events not only reported in the media but also in the known universe. For the first time ever, we have definitive evidence of two neutron stars colliding and releasing a deadly gamma-ray burst. The light from this burst arrived almost simultaneously with gravitational waves unleashed by the collision.
This discovery is proof that gravitational waves travel at the speed of light – a prediction that Albert Einstein made over a 100 years ago. Moreover, follow-up observations in the days following the first offered proof that over half the elements heavier than iron are created in such cataclysmic events in the universe.
Earlier this year, the physicist trio of Rainer Weiss, Kip Thorne, and Barry Barish won the Nobel Prize for physics for their contributions to building the gravitational wave detector called LIGO and its first direct detection of gravitational waves in 2015.
According to Einstein’s theory of general relativity, when two massive bodies accelerate or collide with each other, they release gravitational energy. Such energy deforms the spacetime fabric as it travels outwards from the source at the speed of light. Imagine ripples radiating outwards when a rock hits the surface of a still pond. LIGO (Laser Interferometer Gravitational-wave Observatory) is made of two detectors located in the US. It observed one set of waves in September of 2015, when two black holes orbited each other faster and faster, coming closer until they collided. The event occurred 1.4 billion lightyears away and let loose 178.7 billion trillion trillion trillion joules of gravitational energy
LIGO then detected another black hole merger from approximately the same distance away in December 2015. A third observation followed in January 2016, of two black holes that collided 2.9 billion lightyears away. The fourth was made in August 2017, of two black holes colliding 1.8 billion lightyears away. LIGO’s ‘listening’ in on these collisions has helped scientists establish that black holes merging to form bigger black holes is quite a common occurrence in the universe.
LIGO’s success spurred the creation of more observatories, setting the stage for a new kind of astronomy altogether. In 2016, the Virgo detector in Italy – a collaborative effort by Italy, France, the Netherlands, Poland, Hungary and Spain – was revamped to become more sensitive than before. It joined the two LIGO detectors to hunt for gravitational waves. All three of them are ‘advanced’ detectors and observed the fourth wave on August 14 this year.
But then, only three days later, the trifecta detected a fifth set of waves, the strongest yet. And exactly two seconds later, two telescopes orbiting Earth saw flash of a gamma-rays from the same point in space. It wasn’t from black holes.
What was different this time?
The first four observed gravitational waves were all caused by two black holes rapidly orbiting each other and eventually colliding, forming a new and larger black hole. However, black hole mergers are not the only events that can produce gravitational waves.
Black holes are part of a group called compact objects: they are the remains of a star after it has died. The two other main compact objects are white dwarfs and neutron stars. The former is formed when a star up to eight times the mass of our Sun expands as it grows old and sheds its outer layers, retaining only the core. A neutron star is formed when a star that weighs more than eight- to thirty-times the solar mass explodes in a supernova. (By the way, supernovae also produce gravitational waves).
Neutron stars are the smallest and densest stars in the universe (even though they don’t make their own energy). Such an object will weigh 1.5-2 times the Sun but will measure only 10-20 km wide. A teaspoon of neutron star material would be heavier than Mt Everest; a can of Coke will weigh more than all the humans on Earth combined. The particles in this structure are so tightly packed together that protons and electrons merge to form neutrons. So these objects are almost entirely made up of neutrons. They also spin rapidly, creating extremely powerful magnetic fields around themselves.
On August 17, just like the previous binary black holes, LIGO witnessed two neutron stars spinning around each other, accelerating, before finally making contact – although it was anything but gentle. This process unleashed gravitational waves, some of which LIGO detected. This official name of this collision is GW170817.
Two seconds after the waves were produced, the resulting merger released a gamma-ray burst (GRB). GRBs are one of the most powerful explosions in the universe. In 10 seconds, they liberate as much energy as our Sun would in 10 billion years. The burst is being called GRB170817A.
GRBs are also the brightest electromagnetic events known to occur. They can be seen with the naked eye even if they are billions of lightyears away. This is because the energy in a GRB is released in the form of a beam of radiation: it is focused and directional, like laser. Thus, it preserves enough energy to travel across billions of lightyears, even as its source’s radiation (other forms) can’t be seen by us at all. If a GRB were to light up in the Milky Way and aim straight for us, our planet will be fried, wiping out all humanity. But don’t worry yet our galaxy doesn’t host any stars massive enough to pose this threat.
While scientists had known that GRBs are emitted when massive stars collapse to form a black hole, they’d only theorised that GRBs would also appear when neutron stars collide. The two space telescopes that confirmed the first observation were NASA’s Fermi Gamma-ray Space Telescope and ESA’s INTErnational Gamma Ray Astrophysics Laboratory (INTEGRAL).
The tricky part about observing GRBs is zeroing in on the exact location of the source. We can detect a flash of light but the only way to find out what caused it is to observe the afterglow: signals that reach us later, like X-ray, infrared, ultraviolet, and microwave radiation. And in the initial days of GRB observations, the bursts disappeared before telescopes could turn to look at the source. But today, we have a slew of telescopes actively searching for GRBs that are also ready to jump in to observe the afterglow from one. The afterglow of GW170817/GRB170817A was observed for 10 days in X-ray, optical, radio-frequency and infrared light. And they also had help from the ground.
As soon as the gravitational waves hit us, several large telescopes in Chile were asked to look at the patch of sky, towards the Hydra constellation. After a few hours, the Swope Telescope first saw a prick of light in the NGC 4993 galaxy just as the European Southern Observatory’s Visible and Infrared Survey Telescope for Astronomy (VISTA) saw infrared radiation from the same point. As night fell across different countries, more telescopes pointed towards NGC 4993, including India’s AstroSat, Giant Metrewave Radio Telescope (Pune), and the Himalayan Chandra Telescope (Hanle). Many of them picked up the source in their own wavelengths, confirming that the gravitational waves and the GRB did indeed originate from a binary neutron star merger in the galaxy.
Over the next few weeks, NGC 4993 became the target of several independent observations. Nearly 70 observatories around the world observed the afterglow, resulting in one of the biggest scientific collaborations in modern astronomy. And at its end, scientists concluded that the merger had produced both gravitational waves and electromagnetic radiation, followed by a gamma-ray burst, 130 million lightyears away. So this the closest source of gravitational waves and GRBs we’ve spotted thus far.
An infographic showing the sequence of events associated with GW170817/GRB170817A. Credit: C. Evans/K. Jani/Georgia Tech
The explosion that follows a neutron star merger is called a kilonova, and astronomers have finally observed one after it was predicted nearly three decades ago. A kilonova is a radioactive expulsion of heavy metals like selenium, ruthenium, gold and platinum, flung out into space at nearly 20% the speed of light (about 60,000 km/s). The GW170817/GRB170817A kilonova, which ejected almost a 100 billion billion billion kg of material, was observed to contain the elements caesium and tellurium.
Astrophysicists have believed for a while that over half the elements heavier than iron in the periodic table are born in neutron-star mergers. These heavy elements are created through a process called rapid neutron capture: free neutrons attach themselves to any heavy nuclei and form even heavier elements. The nuclei of these heavier elements then spread out and infiltrate all nearby galaxies, getting into the dust and clouds that form other stars and planets. “Every bit of gold we mine on our planet and put in the ornaments we wear has traveled to us from the collision of such neutron stars millions of light years away,” explained Karan Jani, a scientist with the LIGO team at the Georgia Institute of Technology.
So what’s the big deal?
The science is novel and splendid – but what really is the significance of these results?
Foremost: just the sheer thrill at having observed a neutron star merger. There is a reason why we observed four, almost back-to-back gravitational waves from black hole mergers but it took us nearly two years to observe a neutron star merger. “Double neutron star mergers produce gravitational waves of lower amplitude than those produced by double black hole mergers,” Elena Pian, of the Istituto Nazionale di Astrofisica, Rome, and lead author of one of the papers, told The Wire. “Therefore they can be detected only if they are very close by. This dramatically reduces our probability of finding them.”
Scientists believe something as loud as GW170817 has a probability of occurring only once a decade.The same holds for other phenomena that can emit gravitational waves, like supernovae, making the observation quite rare.
Second, the burst GRB170817A gives us a vital piece of information about GRBs: this jet was not aimed at us, and we still managed to catch it. The GRB initially looked like every other short burst we see (there are long bursts, too, created by other processes). It was dimmer than the expected calculated brightness of a GRB coming straight for us, and lasted less than two seconds – just like the hundreds of other short GRBs we’ve observed.
Astronomers have hypothesised that this could be because the jet isn’t directed directly at us. We could have followed up sighting of a dim jet with observations of the afterglow for two days or so, but nothing would have showed up because we weren’t in the path of the jet. Had we been directly in its path, we would have observed the X-rays much quicker.
It turns out we got lucky. This time, the beam was directed away from us just by 30º or so, so its afterglow reached us, albeit after several days. Given that we’d had a set of gravitational waves with which we could calculate the precise location of the burst, we used the jet’s brightness along with the afterglow data to calculate the angle at which the jet had been shot out.
“If it was not associated with a gravitational signal, it is likely that GRB170817A would not have been followed up in X-rays, not for 10 days anyway, and the discovery of its delayed X-ray emission would not have been made,” says Pian. This solves what she calls a long-standing fundamental problem in astrophysics: whether dim, short GRBs and brighter, short GRBs are actually the same thing observed from different angles.
Third, this observation marked the birth of a new chapter for astronomy, titled ‘multi-messenger astronomy’. Imagine you’ve only been able to hear the sound of a tiger: its roar is deep, loud, rumbling. You can tell that the animal is big. The snarly accompaniments would mean it is probably defensive. Then, one day, you see the tiger, and all of a sudden, you are now barraged with information. Those fang-like canines means they rip through meat. The striped coat indicates they blend well with their surroundings, and which means they stalk their prey hidden. Their hind legs are longer than their front legs, which means they jump very well and could probably take down bigger animals. You now know that these creatures are powerful predators. The day you see a tiger hunt will be the day your theories will be tested.
Today, we’ve seen a tiger hunt.
A snapshot of a computer simulation showing the evolution of a neutron stars collision. Credit: Stephan Rosswog, Stockholm University, Sweden
GW170817/GRB170817A was the first joint effort in gravitational interferometry and electromagnetic observations. The electromagnetic information from the kilonova tells us a lot about the new elements that were synthesised. When put in the context of the information from the gravitational waves: they will help us understand stellar evolution better.
Going back in time
Astronomers were also able to use GW170817 to calculate the rate of expansion of the universe. Going by how the light from the GRB was distorted and the gravitational waves data giving us the distance of the neutron stars from us, we can tell how fast the neutron stars were away moving from us. Working backwards, we calculate the age of the universe (i.e. ‘how long ago was the universe really, really small’). It’s consistent with our previous estimates: our 13.82-billion-year-old universe is expanding at 67 kilometers per second per megaparsec (a megaparsec is 3.26 million light years) in all directions. The farther an object is, the faster it is moving away from us. “It has worked out brilliantly,” says Pian. “We need to pursue this avenue and make sure all pieces of information that come from the two different channels, gravitational and electromagnetic, are put in context and exploited optimally.”
And this will happen. We’re already comparably good with gravitational-wave astronomy as we are with electromagnetic astronomy. While the former is still a fledgling field, it is growing quite quickly. The two LIGO and the Virgo interferometers, and the less sensitive GEO600 detector in Germany, will soon be joined by the proposed Kamioka Gravitational Wave Detector in Japan. In 2023, LIGO-India, officially known as Indian Initiative in Gravitational-wave Observations (IndiGO), will join them as well.
Days after the first gravitational waves detection was publicised, Prime Minister Narendra Modi announced that the Indian project had been approved and a site for the interferometer would be set up in Maharashtra’s Hingoli district. Indian scientists have made valuable contributions to gravitational wave science over the last 30 years. Forty scientists from thirteen Indian institutions are part of the LIGO-Virgo discovery paper, according to IndiGO’s press release. “As a scientist, it is very reassuring to see that India is investing in a field that is just beginning,” said Jani. “Building such mega-science projects allows Indian universities to participate in cutting-edge research, which trickles down to impacting undergraduate education.”
“It provides a unique opportunity for the Indian scientific community to be a major player in an emerging research frontier,” added P. Ajith, a gravitational wave astrophysicist at the International Centre for Theoretical Sciences, Bengaluru, a member of the LIGO collaboration. “The enormous science and technology challenge involved in this project will motivate some of our best minds to work in India, hopefully putting some break on the brain drain.”
A strong gravitational wave detection network, together with electromagnetic observations, would allow us to observe more such wonders of the universe. Pian hopes that “LIGO-Virgo will also detect neutron-star/black-hole mergers that we can follow up with our telescopes and understand the analogies and differences in the nucleosynthesis occurring in them.”
Will we observe a supernova with the same instruments any time soon? “If a supernova happens in our own galaxy, LIGO and Virgo will be able to detect gravitational waves from it – although supernovae happen in a galaxy once in about 50 years only,” Ajith clarified. “LIGO-Virgo scientists are actively searching for gravitational waves from rapidly rotating neutron stars. We know that they exist since radio telescopes have observed about a thousand of them” in the Milky Way.
Ultimately, gravitational-wave astronomers want to get back to the Big Bang itself – the same mysterious, explosive event that is thought to have birthed our universe. For about the next 380,000 years after the bang, all the electromagnetic energy was ‘locked in’ with matter particles, not freely moving around. Information about what happened in this time was thus not recorded in the electromagnetic energy, so even though it is loose around us today and detectable in various forms, they don’t tell us any stories about the early universe. However, the gravitational energy in the first 380,000 years could tell us something. Gravitational waves can’t be stopped by anything in their path. They travel the spacetime, even though they get weaker and weaker, as long as they have the spacetime continuum itself.
‘Catching’ these supremely feeble gravitational waves would require detectors many kilometres long, if not longer – but the day we do catch them… That day, to rephrase William Blake, we’ll see a world in a grain of cosmic sand, and hold infinity in the palm of our hand.
‘It may be the size of the Asian rivers, large because they drain the Himalayas, that makes the pollution so prominent.’
“It may be the size of the Asian rivers, large because they drain the Himalayas, that makes the pollution so prominent.”
The Indus river in Kashmir – not so pristine? Credit: maxos_dim/pixabay
Lakshmi Supriya is a freelance science writer based in Bengaluru.
In vintage crime novels, there is often somebody murdered by slow poisoning, and arsenic has been a common weapon of choice. It works the same way in your body – slowly killing you – if it is present in the water you drink beyond a certain threshold. This is why it’s disturbing that, according to a new study, the groundwater along the densely populated Indus river basin in Pakistan is severely contaminated with arsenic, putting the health of over 50 million people at risk.
Arsenic occurs naturally in Earth’s crust. It is used by humans in some alloys in car batteries and semiconductors, as well as to make some pesticides and herbicides. Certain inorganic compounds that contain arsenic are highly toxic. Exposure in small doses causes headaches, dizziness, diarrhoea and changes in skin colouration. When the poisoning becomes acute, convulsions, vomiting and muscle cramps can be caused. Prolonged exposure to arsenic affects various organs – including the lungs, skin and the kidneys – leading to various types of cancers and ultimately death. Arsenic in the soil accumulates in plants, especially in leafy vegetables and apples, and may inhibit plant growth. However, it is at its deadliest to humans when it pollutes groundwater used for drinking or irrigation. It has been estimated that about 200 million people worldwide use such arsenic-contaminated water.
Investigations into the quality of groundwater from the previous decade have revealed that the large river basins in South Asia contain harmful levels of arsenic. The Ganga-Brahmaputra delta in India and Bangladesh and the Red River basin in Vietnam are greatly affected.
The effects of drinking arsenic-contaminated water in India emerged most prominently in the early 1980s in West Bengal and, over time, in other states in the Gangetic plains, such as Bihar and Uttar Pradesh, and in the Brahmaputra basin, including in Assam and Manipur.
The areas usually affected are low-lying, where the movement of water is slow and its flow carries a large amount of sediments. This reduces the amount of oxygen available in the water, which forms the stable and more water-soluble compound arsenite. Once the oxygen levels begin to drop, arsenic is released from the sediments and into the water, and increasing its concentration in groundwater. “It may be the size of the Asian rivers, large because they drain the Himalayas, that makes the pollution so prominent,” John McArthur, a geochemist at University College London who has been studying arsenic contamination around the world, told The Wire.
While several small-scale studies have found that the groundwater in several areas in Pakistan is loaded with arsenic, the full extent of the problem has remained out of focus. “The original motivation for the country-wide sampling campaign came about from wanting to identify the full scope of the arsenic contamination problem in the country, which is what our study has accomplished,” Joel Podgorski, of the Swiss Federal Institute of Aquatic Science and Technology, Switzerland, and the lead author of the new study, told The Wire.
Between 2013 and 2015, the researchers collected more than 1,100 water samples throughout the country from both household pumps and municipal and agricultural tube wells, and analysed these samples for arsenic and other elements. Using this and previously published data, along with hydrological and topographical data for the country, they were able to visualise the full extent of the problem.
According to the World Health Organisation, more than 10 micrograms of arsenic per litre of water is hazardous to health. Pakistan’s official guidelines recommend an upper limit of 50 micrograms per litre of drinking water.
Podgorski and colleagues found that the water was heavily contaminated along multiple points of the Indus. As it made its way across the length of Punjab (especially along the banks of the tributaries Ravi and Sutlej), entered northern Sindh and emptied into the Arabian Sea south of Karachi, arsenic levels frequently crossed the 50 micrograms mark. In northern Sindh, a cluster of samples showed more than 200 micrograms of the metal per litre of water. Beyond the plains watered by the river and its tributaries, the arsenic levels were within safe limits.
According to Podgorski, there are several reasons the Indus basin is so plagued by arsenic – apart from the river’s sluggish flow in the plains, which causes arsenic to accumulate in aquifers. The sediments being washed out from the Himalayas are still relatively young, less than 10,000 years old. Compared to older sediments that would have already leached out their arsenic from the sediments, these have been exposed to the environment only recently, and are still in the process of releasing their arsenic into the water.
Specifically, they found a strong correlation between high arsenic concentrations and the pH of the soil. A higher pH causes arsenic to be released easily from the sediments and into the water. It may be possible that in the arid central plains of Pakistan, the highly alkaline soil (corresponding to higher pH) enhances the release of arsenic from the sediments, especially to water near the surface, which could then migrate to deeper sources.
“The fact that irrigation correlates highly with arsenic contamination in the Indus valley leads us to speculate that it may be contributing to – but not exclusively causing – the problem by raising the pH of the soil through evaporation and transporting the released arsenic to the aquifer depth,” Podgorski explained.
The study estimates that the high level of contamination puts about 50-60 million people living along the Indus basin in the Sindh and Punjab provinces, including the densely populated cities of Lahore and Hyderabad, at risk of drinking toxic water.
“For those living within the Indus Plain, their water supply should be tested for arsenic, since not all wells in this area are contaminated,” Podgorski said. “In fact, contamination can be so heterogeneous that wells within the same village can have both safe and unsafe concentrations of arsenic. Only once all of the wells have been tested is it possible to know from which wells it is safe to take drinking water.” Once toxic wells have been identified, either that well should be closed or arsenic filters should be installed.
But despite the scale of the problem, both Podgorski and McArthur agree that the contamination will not spread to any new areas, as rivers only flow downhill. However, McArthur said that arsenic-rich water can spread to more areas within the same basin at a rate of a few sq. metres per year in the big delta and alluvial plains.
The extent of the problem today is significant and affects a large number of people, and McArthur says that the first step in helping the affected people is for the government to recognise that there is a problem. Once it does, then it could help ensure that people get piped water from local arsenic-free wells or from contaminated sources that have been treated.
Turtle-headed seasnakes (Emydocephalus annulatus) in polluted waters are changing colour. Creatures of the Indo-Pacific coast, they usually have high contrast black and white bands or blotches encircling their bodies from head to tail.
While snorkeling in the shallow Nouméa lagoon of Grande Terre Island, New Caledonia, more than 1,000 km east of Australia, evolutionary biologist Rick Shine of the University of Sydney and his family observed unusually black turtle-headed seasnakes. Back then, in 2003, males, the smaller of the sexes, seemed more prone to melanism (80%) than females (54%). These waters are polluted by runoff from nickel mining, the largest employer in this French protectorate. Besides the black seasnakes, Shine observed some retained faint bands. What’s causing the startling white rings to disappear?
Dark colours absorb heat, a useful trait for land reptiles in cold countries. But dark aquatic snakes gain no advantage because water is not a conductor of heat, says Shine. Nonetheless, entire populations of black individuals frequent the waters of Saumarez and Ashmore Reefs, Australia. However, in New Caledonia, the banded phase is prevalent and black snakes were not common in earlier years.
Turning black in response to pollution, a phenomenon called industrial melanism, afflicts many creatures, chief among them insects. With soot settling on their environment, several species of light-coloured moths stood out and became an easy meal for insectivorous birds. A surfeit of melanin turned some of them coal black. Since these insects matched sooty surfaces, they evaded predators. First recorded in 1848 in Manchester, UK, dark peppered moths (Biston betularia) became common within 50 years, almost replacing the speckled light phase.
However, black turtle-headed seasnakes don’t restrict themselves to backgrounds that match their body colour. When banded creatures move, they create an optical illusion: They seem to travel in the opposite direction and thus evade their killers. So losing bright bands wouldn’t be to the turtle-heads’ advantage.
Nor could black confer any advantages in catching prey. All males, females and the young scrape fish eggs off coral, and they don’t have to lie in ambush since their meals aren’t about to escape by swimming away.
“Initially I thought it might relate to habitat differences and camouflage; then perhaps mate choice and sexual selection,” Shine told The Wire. “But we gathered a lot of data, and neither of those two ideas worked out.”
What then could be the reason for the colour change? The explanation for why snakes of the same species living in the same lagoon have different colours had to wait 14 years.
In 2014, researchers from France published a study of pigeons becoming darker because of pollution. It wasn’t a result of soot settling on the Parisian birds’ plumage and making them dusky. Instead, contaminants such as zinc stuck to melanin in the darker feathers. This ability to detoxify their internal organs of harmful chemicals by shunting them to their feathers allowed dark-coloured birds to become more successful in cities than pale ones.
“I read the pigeon paper shortly after its publication, and I immediately thought that the link between pollution and melanism could explain why so many Emydocephalus annulatus were black,” Claire Goiran, a marine biologist at the University of New Caledonia, Nouméa, told The Wire.
(A) Emydocephalus annulatus (melanic specimen sloughing). (B) Melanic and banded E. annulatus from a peri-urban population near Noumea. (C) Frequencies of melanism in snakes from urban-industrial sites versus other areas.
Goiran and Shine compared 1,400 specimens that Shine had collected over 13 years. The samples came from the polluted waters along the coast of New Caledonia and the clear seas of Barrier Reef atoll in Australia. An overwhelming majority of the black seasnakes came from contaminated waters, while the ones in non-industrial areas had stark bands.
When pollutants enter their systems through their diet, they collect in the snakes’ skins. For instance, the shed skins of corn snakes contained high levels of lead, cadmium and mercury after researchers fed them contaminated mice.
In addition, seasnakes could also absorb chemicals from the water through their skins. All these contaminants, within their bodies and outside in the environment, accumulate in the skins just as they collect in pigeons’ feathers.
Shine and his colleagues found higher concentrations of trace elements in the shed skins of jet black turtle-headed seasnakes. Of the 13 pollutants they detected, five – cobalt, manganese, nickel, lead and zinc – were especially concentrated at levels that could cause health problems in mammals and birds. Even in banded ones, the black sections of the sheds had more contaminants than the white sections. Becoming black appeared to be a way of excreting pollutants.
Black snakes shed their skins oftener than pale ones because algal spores tend to accumulate on dark surfaces. If they didn’t slip off their skins, growing algae create drag, slowing down the snakes. In toxic waters, this frequent sloughing would not only get rid of algal spores but also the adhering contaminants.
Such adaptation to human activity can be rapid. In peppered moths, the mutation for black colour occurred as recently as 1819, nearly three decades before the first record. In turtle-heads, the researchers suspect the mutation for melanism is unique to the species. Seakraits (Laticauda sp.) are similarly banded, but the mutation to make jet black individuals may not have occurred yet even though Goiran and Shine found pollutants in the dark-ringed sections of their sloughs.
This is the first and only evidence of a snake changing its colour in response to industrial contamination.
Since pollution would affect both genders, why are males overwhelmingly melanistic?
“The sex bias isn’t very strong, and I haven’t looked at the data recently – the difference may even have disappeared,” says Shine. “But if it’s real, it might reflect the fact that male and female turtle-heads feed in different seasons, on the eggs of different types of fishes. One type may well have more pollutants than another.”
Despite the number of black seasnakes they observed, the Shine family didn’t catch a black-coloured juvenile. All the youngsters they caught were brightly banded, but Shine doesn’t think they change colour in their lifetime.
Since black turtle-heads are better at coping with pollution, it’s possible they may outnumber the banded ones just as dark peppered moths replaced light ones. However, this blackening of a species may not be irreversible. With stricter laws to check pollution in Britain, the light-coloured peppered moths are returning. Turtle-heads probably could retain their vivid banded forms off the New Caledonian shore if contaminants didn’t spill into the sea.
The study was published in the journal Current Biology on August 10, 2017.
Janaki Lenin is the author of My Husband and Other Animals. She lives in a forest with snake-man Rom Whitaker and tweets at @janakilenin.
Rather than allowing every protest to degrade into name-calling, where protestors are branded ignorant or anti-national, it may be worthwhile to engage with substantive issues raised by them.
Rather than allowing every protest to degrade into name-calling, it may be worthwhile to engage with substantive issues raised by them. To this end, an FAQ follows.
Villagers protesting in Neduvasal. Credit: Nityanand Jayaraman
On February 15, 2017, India’s central government announced the award of contract for development and extraction of hydrocarbons from 44 contract areas nationwide, including 28 on-land fields and 16 offshore. Within a day of the announcement, protests broke out in Neduvasal, a little known village in Pudukottai district in southern Tamil Nadu.
The Neduvasal oil field had been awarded to Karnataka-based Gem Laboratories. Less than two weeks following the announcement, the agitation has gathered steam, feeding off the young energy from the recently concluded protests against the ban on jallikattu. Proponents of the project have questioned the credentials and intelligence of the protestors. Union minister of state for shipping, road transport and highways Pon Radhakrishnan has appealed to the people not to oppose the project blindly. “Are all of them scientists who know enough to oppose the project?” he asked.
The people of the villages in and around Neduvasal are not aware of the project’s specifics. However, interactions with protestors suggest that what they know in general about oil exploration and production, and about the track record of ongoing oil production operations in Nagapattinam, Tiruvarur and Thanjavur districts, is robust enough to form an opinion on the desirability of the project.
The region’s farmers fear that hydrocarbon extraction will disturb the comfortable agrarian economy extant in this region. Neduvasal is located in an area rich in groundwater and blessed with the fertile soil of the delta. Unlike the lower reaches of the delta, where agriculture is in distress, Neduvasal still has a healthy multi-crop farm economy.
The issues raised by the protestors are worth engaging with. Rather than allowing every protest to degrade into name-calling, where protestors are branded ignorant, anti-national, misled or foreign-funded, it may be worthwhile to engage with substantive issues raised by them. To this end, the following is an FAQ on the subject.
The people of Neduvasal are blindly opposing the project. How can they oppose it without knowing the specifics of the project, especially when ONGC has been successfully extracting hydrocarbons in the delta region for decades without protest?
While specific information may not be available, villagers are aware about the general consequences of hydrocarbon extraction thanks to a successful and popular campaign against a controversial coal-bed methane (CBM) project in Thanjavur between 2010 and 2016. Led by the late G. Nammalwar, a popular organic farming proponent, the campaign included a massive awareness drive to educate villagers about CBM as well as about how hydrocarbons are extracted from Earth, the effects of such operations on the environment and on people’s livelihoods.
An exploratory well constructed by ONGC near Neduvasal in 2008-2009 also gave villagers a sense of things to come. “For three months after the well was dug, they would burn the gas night and day. Sometimes the gas would burn orange with black smoke, and sometimes blue with no smoke,” says T. Amudha, an engineering graduate who gave up her job in Chennai after being disillusioned by city life to return to farm in her village. Pointing to a pit filled with oily wastes, she says, “Look at that. That has been lying there for seven years. If there are heavy rains, the wastes flow out of the pond into the neighbouring lands. This is only a small quantity, generated during the exploration stage. Much larger quantities will be generated during oil production.”
“With this in front of me, how am I to believe that they will behave responsibly?” she asks.
Within 100 km from Neduvasal, ONGC operates about two-hundred oil wells and a score of other installations. ONGC’s track record of operating these wells is bad. In 2010, 2011 and 2012, crude oil leaked from underground pipelines running through people’s fields in Nagapattinam and damaged standing crops, irrigation canals and contaminated groundwater.
K. Dhanapalan, a farmer and activist with the Cauvery Delta Farmers Protection Association, says “Fields damaged by oil leaks are never restored, and a meagre compensation after long-drawn complaints process is all that farmers see. Lands scarred by oil take years to recover.”
Incidents of gas leaks and the threat of fires in residential areas add to the concerns of neighbouring communities.
Farmers turn out in large numbers at public hearings to oppose ONGC’s proposals to sink new wells or expand operations. The concerns raised during public hearings highlight the lack of compliance to environmental regulations by ONGC, and a failure by the district administration and the Tamil Nadu Pollution Control Board to enforce the law. At an environmental public hearing conducted in 2014 for drilling wells in Nagapattinam, air and water pollution, groundwater depletion and increased incidence of respiratory diseases, farmland contamination and lapses in restoring damaged lands and awarding compensation were the most common concerns raised by local farmers.
In 2015, farmers from Tiruvarur demolished a shed being constructed by ONGC on paddy lands citing earlier gas leaks and the company’s poor track record.
Dhanapalan points out that “if people know and trust that the extraction of oil and gas can and will be done without harming the environment, they will not protest. The government must prove that hydrocarbons can be extracted safely by putting its existing operations in order, in restoring damaged farmlands and compensating affected farmers.”
Why did the people of Neduvasal not protest at the exploration stage itself?
The exploratory well in Neduvasal is actually not in Neduvasal but in a neighbouring village called Karukkakurichi, on five acres of land belonging to two brothers, Govinda Velar and Kulandai Velar. Banana and sugarcane were being cultivated on the land at the time. “They first came in 2008. But they never gave me any details about the project,” said Govinda Velar, a potter who lives near a kiln in a spacious tree-lined compound. “They said they were running some tests to see if there was petrol beneath our lands, and that it was only a short-term operation. We did not want to part with the land. But they were persistent and brought in the VAO and the tahsildar, who insisted that this was a government project. They took my signature on a piece of paper. I do not even have a copy of that letter,” he recalls.
The statutory environmental public hearing required to be held under the Environmental Impact Assessment Notification (EIA), 2006, has never been held for the Neduvasal exploration project. The environment ministry’s website, which claims to be up-to-date with all relevant information as part of its ease-of-doing-business and transparency initiatives, has neither an EIA nor an environmental clearance for the Neduvasal explorations.
In fact, only one environmental clearance mentions Pudukottai district. But that, too, is dated 2013 and refers to two locations in Pudukottai: Tiruvonam and Karambakudi. It does not mention Neduvasal.
What is known about the project?
A scene from the protests in Neduvasal, Tamil Nadu. Credit: Nityanand Jayaraman
The Neduvasal oil field reportedly has a seven-year mining lease that expires on December 31, 2019. The leased area is 10 sq. km from within which oil and gas can be extracted by the contractor. The recent award is part of the Indian government’s October 2015 Marginal Field Policy, aimed at inviting private sector participation in exploitation of marginal and small oil fields.
The project is not a coal-bed methane- or shale-gas-extraction project. So the use of hydraulic fracturing or fracking is unlikely – although it can only be ruled out pending further assessments. The proposal appears to be for a conventional oil and oil-associated gas extraction project with total extractable reserves of 430,000 tonnes of oil and oil-equivalent of gas. Speaking to The News Minute, Gem Laboratories has revealed that it has not made up its mind on the technology to be deployed to extract the hydrocarbons.
Onshore exploratory and production wells in the Cauvery delta are drilled to depths of between 1,750 m and 6,000 m. And the Neduvasal field, too, if developed will be drilled on to these depths.
How are conventional hydrocarbons extracted?
Before production wells are dug, developers sink a large number of appraisal wells to physically assess the extent and characteristics of the reservoir. If the Neduvasal project takes off, these wells will be located within the 10-sq.-km lease area.
The entire lease area will not be acquired; only areas around the proposed drill locations will be leased or acquired. Roughly five acres will be required for each drill site. Neither the locations nor the number of such wells are known at this point. Some wells may subsequently be abandoned or converted to other uses.
Production wells are usually dug to the base of a reservoir while appraisal wells may not go that deep. In the early days of production, when pressure differentials are high, oil/gas will gravitate to the low-pressure area at the bore and emerge to the surface on their own. Only 10-15% of the extractable reserves can be harvested at this primary stage.
Secondary recovery involves injecting high-pressure fluids to flush out the oil or gas trapped inside or in the interstices of the source rocks (sandstone, shale, etc.). New injection wells may need to be drilled for this purpose, or existing appraisal wells may be used. In ONGC’s Cauvery assets, “produced water” – a toxic by-product separated from the extracted hydrocarbons – is used for flushing.
Tertiary or enhanced recovery could involve fracturing the source rock using high-pressure fluids along with harder substances, like sand or aluminum beads that will wedge themselves between fissures, to facilitate hydrocarbon flow.
How is drilling done?
Drilling for exploration, appraisal or production have similar consequences. A drill site may require approximately five acres. The site preparation will involve flattening the land, laying access roads, laying concrete platforms to accommodate the drilling rigs and other infrastructure. Land-use change, alteration of drainage patterns, noise and air pollution are key concerns in this stage.
Once installed and the drilling has begun, the rig will operate on electricity from diesel generators 24×7 until the desired depth has been achieved. During this time, air pollution from generator sets and vehicular movement, and noise pollution, are key concerns.
A drilling fluid, usually water-based mud (WBM), is used to protect the structural integrity of the drilled hole, cool and lubricate the drill-bit and to evacuate the excavated drill cuttings (mud, sand and rock chips) to the surface. WBM is the least toxic of drilling fluids. Nevertheless, along with drill cuttings, it may be contaminated with trace levels of arsenic, cadmium, chromium and mercury depending on the geology of the area. This is a waste stream that requires careful disposal.
Drilling is followed by encasing the well with steel and concrete. The steel casing prevents the well from collapsing – and the concrete and steel also insulate the various water aquifers from the oil, gas and hydrocarbon-tainted brine that will emerge from underground once the well begins operating. However, in the time between drilling and encasing, there is a risk of contamination of exposed aquifers to chemicals or material that are part of drilling fluids.
What are the environmental effects likely to be encountered during the lifetime of a well?
A woman farmer with a sickle at the protest. Credit: Nityanand Jayaraman
Failed well sites have to be restored and returned to the land-use that prevailed prior to drilling – that is, agricultural use in the delta region. According to Dhanapalan, this is seldom done. Of the 600 or so wells that are part of the Cauvery assets, only 200 are producing wells. The remainder, barring a few that are used as injection wells, is abandoned. According to Dhanapalan, “None of these have been restored. At five acres a well, that translates to 2,000 acres of fertile land abandoned to become dense thickets of the dreaded karuvelam (Prosospis).” Karuvelam is a thorny weed that desiccates the land and has taken over the Tamil countryside.
The land surrounding the exploratory well in Karukkakurichi, near Neduvasal, is a case in point. While the surrounding lands have standing crops and healthy vegetation, the lands surrounding the idle well is carpeted by karuvelam.
Production wells also pose other challenges:
Produced water – When oil and gas are brought up to the surface, they emerge along with water that coexists with hydrocarbons in the reservoir. This is a significant waste stream by volume in oil-and-gas extraction operations. Where extraction is enhanced through flooding the reservoir with water, the quantities of produced water can be even greater. Depending on the age of the well and the nature of production, between two and nine barrels of produced water can be generated for every barrel of oil extracted.
Produced water is highly saline and corrosive, and will contain hydrocarbons like the toxic benzene, polycyclic aromatics, heavy metals and naturally occurring radioactive material like dissolved uranium, radon and radium. Pipelines or vessel interiors used to store or transport these effluents are prone to corroding and developing scales and salt deposits. The scales themselves tend to concentrate the toxins within the effluent, and ought to be handled as hazardous wastes.
ONGC’s delta operations claim to have 21 effluent treatment plants (ETP) to handle 70 million litres of produced water per day. Some of the treated water is reused in injection wells for waterflooding hydrocarbon reservoirs and the remainder disposed by pumping into old wells. Deepwell injection for disposal or for waterflooding are governed by dedicated rules in other countries and followed up with monitoring as well as informing the public of it.
However, produced water is dealt with casually in India. The EIA reports, which ought to dedicate entire sections to predicting and managing the impact of produced water, has nothing more than one passing reference to the waste stream. No information is available in the public domain about the performance of these ETPs either.
Groundwater contamination can occur if the well casing in production wells fail or wells collapse, exposing the aquifers to produced water and hydrocarbons emerging from the bore. They can also occur in abandoned or idle wells that may not be plugged, or where the plugs get damaged over time. Where and when this happens, hydrocarbons, gases and associated water can enter drinking-water aquifers. Idle wells that are not plugged should be subjected to routine checks for fractures in the casing or other defects. The exploratory well near Neduvasal has not been monitored since it was capped in 2009.
Groundwater, surface water and land contamination can also occur due to improper handling of waste streams – e.g., spills of produced water, temporary or long-term surface storage of produced water or oily wastes, leaks from crude oil pipelines, etc.
Air pollutioncan occur due to fugitive emissions or leaks. Volatile organic compounds (VOCs), including toxic chemicals like benzene (which causes leukaemia), ethylbenzene, xylene and toluene, can be mobilised in the air. Flaring or venting of gases is generally not a good practice as it represents a waste of the fuel that is to be harvested.
However, where this is done, ground-level air quality tends to deteriorate and pose a localised health hazard. Many of the VOCs can combine with nitrous oxides emitted from diesel exhaust to form ground-level ozone, a respiratory irritant.
Since methane – a potent greenhouse gas – is a major constituent of natural gas, venting the gases into the atmosphere can appreciably worsen global warming risks.
Blow-outs and explosions – Hazardous incidents such as blow-outs – caused by sudden surges in pressure inside the bore – result in gases erupting and exploding from the well mouth. These are the most hazardous incidents that can occur at a well site, and result in the discharge of large quantities of pollutants into the atmosphere. A single blow-out can last from a few minutes to several days. The 2010 Deepwater Horizon spill at BP’s oil installation in the Gulf of Mexico has been the worst blowout incident to date. It took five months to tame.
Blow-out risks are sought to be reduced by safety devices and good practices, and are relatively rare.
Land subsidence and salinity intrusion– Large-volume extraction of fluids, such as water or hydrocarbons, can result in land-subsidence. According to the US Geological Service, “This induced subsidence, which is either sub-regional or local in extent, has its greatest impact on flat coastal plains and wetlands near sea level where minor lowering of the land surface results in permanent inundation.”
This is particularly problematic for the delta region, which is already facing sea-water intrusion owing to rising sea levels, rampant sand-mining and the exploitation of underground resources like groundwater, apart from oil and gas. Note: The sections on oil and gas extraction and environmental/health effects of hydrocarbon production has been sourced from several documents, including those already cited above. More here, here and here.
Nityanand Jayaraman is a Chennai-based writer and social activist.
Surface water is used for diverse purposes but the water’s quality is tested only to suit a few.
Surface water is used for diverse purposes but the water’s quality is tested only to suit a few.
Credit: vinothchandar/Flickr, CC BY 2.0
The different set of standards set by India’s pollution control authorities for rural and urban water quality monitoring is based on a fallacious assumption that surface water in rural areas is pristine and free from toxic heavy metals. The points of discharge into surface water bodies and the points of use of water for irrigation, drinking or bathing are all variously monitored in rural and urban areas, leaving out crucial indicators during one measurement or the other.
Most Indian cities lack basic wastewater treatment infrastructure, resulting in urban rivers receiving a sizeable portion of domestic and industrial sewage. Water from these rivers is often used by downstream farmers for irrigation, according to a team of researchers led by Sharadchandra Lele, a senior fellow at the Ashoka Trust for Research in Ecology and the Environment (ATREE), Bengaluru.
India’s Central Pollution Control Board (CPCB) has laid out water quality standards for various uses of river water, including those relevant to discharges in surface water bodies, public sewers and oceans, and reuse for irrigation. However there are several gaps within and discrepancies between these prescribed standards, Lele’s colleague Priyanka Jamwal says.
According to her, lack of heavy-metal regulation in peri-urban water bodies is one of the main gaps. In the absence of regulation for industrial contaminants, the surface water pollutes groundwater, irrigation water and food crops that are produced in peri-urban spaces. “Currently [these] areas are not being regulated for the contaminants that are discharged from urban spaces,” she told The Wire.
No measure of biological activity
The legal basis for pollution control is the Environment (Protection) Rules of 1986. Under rule 3, a separate section addresses effluent discharge standards, including industry-specific and general discharge standards that encompass inland surface water bodies, public sewers, marine coastal areas and land for irrigation.
However, a separate section addresses surface water standards, which includes standards for marine water quality (salt pans and shell fish; bathing and contact water sports; industrial cooling and non-contact recreation; and navigation and waste disposal) as well as standards for inland surface water quality. And the latter sets standards only for bathing water quality. “There are no standards for inland surface water uses,” says Jamwal.
This, in effect, means that the same river water that is used for drinking in a city and irrigation in a village is differently monitored.
Earlier, at a conference of the Indian Society for Ecological Economics (INSEE) in Bengaluru in January, Jamwal presented details of a recent analysis by the ATREE team headed by Lele. Their analysis called for a re-examination of irrigation quality standards, and making effluent discharge standards consistent and compatible with irrigation water standards for downstream use. The discharge points for water include both point sources such as domestic effluents and industrial effluents; and non-point sources such as agricultural run-offs and urban run-offs. The point of use is surface water that is used for drinking, bathing, fishing and irrigation.
Invariably, while physical and chemical parameters and heavy metals are monitored for some water bodies, biological oxygen demand (BOD), which is the amount of oxygen required by aerobic microbes to decompose organic matter in a water sample, goes unmonitored. For example, surface water bodies are monitored for four physical and 17 chemical parameters; and 14 trace metals such as cadmium, iron, lead, mercury, nickel, selenium and zinc – but not BOD.
Similarly, public sewers are monitored for two physical parameters and seven chemical parameters; and 14 heavy metals – but again not BOD. Finally, coastal water bodies are monitored for four physical and 16 chemical parameters, and 14 trace metals, but not for BOD. Worst off is the water meant for land application – such as irrigation: it is monitored for three physical and five chemical parameters, and only two trace metals.
Flawed assumptions
“One basic assumption made by the CPCB while formulating water quality criteria for best-use is that surface water body flows in rural or pristine watersheds, therefore only conventional water quality parameters needs to be regulated,” Jamwal clarifies. “But this assumption is not valid in the context of urbanising watersheds, as urban spaces are expanding and various activities, domestic as well as industrial, in these spaces generate contaminants that need to be regulated to reduce risk to public health.”
During a river flow, in upstream catchment areas that cater to rural habitation, water discharges contain BOD, total suspended solids, chemical oxygen demand and pathogens, but there are no standards to monitor these as they are assumed to be pristine. This water is used for domestic, agricultural, dairy and recreation, and the water quality is only regulated for downstream use, typically in urban areas. As a result, “the reality is that urban streams receive both untreated and partially treated industrial and domestic effluents,” according to Jamwal.
There is an additional effect on water quality as cities become larger: “as distances between two cities’ water flows keep shrinking, natural flows between two stretches of continuous urban water are shrinking. Therefore, there is no dilution of heavy metals entering the urban water flows, and they enter the food chain and impact health,” she adds.
For example, the Musi river that feeds the peri-urban area around Hyderabad was found to have high levels faecal coliforms and heavy metals such as zinc, chromium and copper in 2015. The Hindon river sediments in Ghaziabad city were heavily polluted with cadmium and moderately polluted with manganese, zinc and lead, metals that originate from industrial sources. In fact, heavy-metal levels as well as the BOD in the Kasadri river near Maharashtra’s Taloja industrial estate were much higher than the maximum permissible limits.
Similarly, the Yamuna river that feeds into Delhi and Agra was found to contain high levels of nickel, cadmium and chromium. Faecal coliform levels were above permissible limits thanks to domestic sewage and urban run-offs. And the Ganga, near Kolkata, contains excess concentrations of iron, manganese, lead and nickel, and is not suitable for irrigation. The excess of heavy metals load in its waters is attributed to the discharge of industrial effluents and municipal wastes, not to mention the geology of river bed and catchment areas as well.
In addition to separate sections addressing discharge water and surface water bodies, “there are further challenges in monitoring,” say Lele and Jamwal. Their team founds discrepancies when analysing the chemical and biological quality of the Vrishabhavathi river in southern Karnataka, which receives partially treated industrial and domestic wastewater from the western portion of Bengaluru city. The water is mainly used by farmers in villages downstream for agriculture.
“Though the levels of toxic heavy metals and faecal coliforms are dangerously high, posing significant risk to farmers as well as urban consumers of the food grown, the river is classified as fit for irrigation, as per CPCB standards,” the duo says. “The water meets the irrigation water quality standards set by CPCB because CPCB assumes ‘natural river flow’ when setting this standard, whereas flows in urban streams are often dominated by partially treated domestic and industrial effluents.”
Inadequate sampling methods
Also, the standards set for effluent reuse for irrigation are completely different from those set for irrigation use of surface water. The effluents reuse standards comprise eight parameters including heavy metals such as arsenic and cyanide. However, surface water used for irrigation should only comply with water quality criteria comprising four water quality parameters that do not include heavy metals.
The result is that “rivers that carry partially treated sewage from cities to downstream farming regions fall through the cracks. They are neither conventionally understood rivers nor conventionally defined effluents,” says Lele.
The method of sampling water for quality tests is also inadequate. The INSEE team compared results of grab-sampling versus hourly sampling. A grab sample does not reflect the true extent of pollution. ATREE found that night time samples are far higher than daytime samples.
The INSEE team recommends that all significant uses – drinking, bathing, fisheries – must have standards that include criteria for heavy metals and other chemical contaminants. The irrigation use standards must include criteria for heavy metals and other chemical contaminants that effect soil quality, health of farmers and the food chain. It follows that the standard for discharging effluents directly to land must meet the quality standards for irrigation use set in the second point above.
It also recommends that rather than having separate quality standards for ‘marine’ uses, these standards need to be included with other ‘use’ standards, and must also include the criteria for industrial contaminants. Finally, in-stream quality standards must include standards for heavy metals and all other chemicals that are likely to effect ecosystem health.
Multidisciplinary approach to setting standards
Research studies on water-quality monitoring involve multidisciplinary science, which in turn involves techniques from hydrology, geology, hydrometeorology and geospatial technology, explains Subhankar Karmakar, associate professor, Centre for Environmental Science and Engineering, IIT-Mumbai.
“The existing techniques of rationalisation are rigorous and mathematically complicated. In realistic situations, mostly the watershed managers and other stakeholders may not have knowledge of all these interdisciplinary branches and will be unable to implement rationalisation algorithms in the field,” he says. Therefore, there is a need for software packages to facilitate efficient rationalisation and operations of water quality monitoring programme.
There are also budgetary constraints while designing a water-quality monitoring network that need to involve decisions of a number of monitoring stations, Karmakar adds. Each sampling involves high installation, operational and maintenance costs.
Additionally, while there is no universally accepted approach for rationalising monitoring networks, it is still the prime responsibility of central and state-level pollution control agencies to standardise water quality networks for sustainable management. For this, they should consider data availability issues of both quantity and quality; seasonal variability and need for periodical assessment; and application of geographic and remote sensing tools.
Karmakar’s team is working on improving design practices and protocols. They have shown that data-driven and conventional topology-based techniques could overcome some of the current drawbacks, especially by helping to collect both point and diffused samples during different seasons.
A joint initiative of the Central Water Commission, under the Ministry of Water Resources, and the National Remote Sensing Centre, under the Indian Space Research Organisation, has led to the development of an inventory that provides, stores and analyses data, and converts it into an interactive format. While the initiative is “undoubtedly novel, most of the water quality data sets are not continuous, and are inconsistent,” says Karmakar.
