Groundwater has been the lifeline for millions across the country. As much as 80% of rural and 50% of the urban population of India depend on groundwater for domestic and irrigation purposes. Karnataka is not an exception. As much as 99% of the state is covered by hard rock aquifer, except in coastal areas where alluvial aquifer dominates. Erratic rainfall, over extraction of groundwater for agriculture and natural and man-made pollution has endangered this precious source of water, prompting urgent need to form strict regulation to protect, preserve, harness and improve the groundwater table.
The water table is rapidly falling in several parts of Karnataka because of over-exploitation of groundwater, mainly for irrigation. The Central Groundwater Board data shows the groundwater in as many as 82 taluks are in either over-exploited, critical or semi-critical stages — that means, in several parts of the state, more groundwater is being extracted than it is being recharged by rains. The result is eye-popping: groundwater level across 70% of the state falls rapidly in the post-monsoon season, leaving many of the dug wells dry.
The groundwater problem is being worsened by toxic natural and man-made contaminants. Salinity, chloride, fluoride, iron and arsenic are the predominant natural contaminants in the state. Fluoride, the cause for bone deformities and fluorosis, is found exceeding permissible limits of 1.5mg/litre in the samples collected in 20 districts by Central Groundwater Board. Raichur has the worst fluoride concentration, followed by Kalaburagi and Ballari.
Agriculture not only uses more than 80% of the groundwater extracted but also adds nitrate, phosphate, pesticides and herbicides. As many as 25 districts have nitrate exceeding critical limits of 45 mg/l. Too much nitrate in drinking water poses a risk to infants under six months of age, causing “blue baby syndrome.” Bacteria which are present in an infant’s stomach can convert nitrate to nitrite (NO2), a chemical which can interfere with the ability of the infant’s blood to carry oxygen. No data is available for other more potentially toxic compounds such as pesticides.
Experience in the industrialised world shows that industries are the major sources of contaminants. Various industries manufacturing cars, textiles, polymers, electronics, electroplating, paints, dry-cleaning, glass, chemicals, etc., use a wide range of chemicals in their processes. Many a time, these chemicals are released into the soil because of improper handling, leakage of pipes or underground tanks and accidental spillage, etc. Unfortunately, some industries illegally inject untreated industrial effluents into the groundwater. Even mining and petroleum exploration activities release various metals and hydrocarbons.
No major systematic study is undertaken to estimate groundwater contamination due to industrial activities, although reports about the issue periodically surface in the media. A Central Groundwater Board report and a survey by the Karnataka Pollution Control Board in Bengaluru’s Peenya industrial area have found hexavalent chromium — a common chemical used in the electroplating process — contamination in 20 out of 72 borewells. The extent of chromium, a known carcinogen, in some wells was found to be 600 to 700 times above the national permissible limit of 0.05 mg/l. The abandoned gold mines at Mangaluru and green stone belt of Yadgir district were reported to have arsenic as high as 30 times WHO standards. Nearly 60% of people in Kirdali Tanda village near the gold mine were found to be suffering from arsenical symptoms.
These reports are just the tip of the iceberg. Surprisingly, data published in the Groundwater Year Book of Karnataka by the Central Groundwater Board for 2015-16 shows 97% of the samples are within permissible limits for drinking water. But these surveys, conducted by government organisations, confine themselves to some narrowly selected parameters, such as arsenic, fluoride, nitrate and iron and totally miss more toxic and carcinogenic substances such as chlorinated organics, metals (chromium, mercury, lead, selenium, etc.), petroleum hydrocarbons (benzene, toluene, xylene, etc.), phenolic compounds, PCBs, dioxins, cyanides and pesticides. They are known to cause cancer, kidney failure, liver damage, birth defects, etc.
Further, most of the data obtained are from open wells or hand pumps. Groundwater monitoring wells properly installed in the potential contamination sources such as industrial areas must be selected and the analytical parameters should cover chemicals specific to the industrial area. Lack of such initiatives show the urgent need to educate the regulating bodies and even leading research institutes in the country about the contamination problem and site investigation techniques.
In India, groundwater is a state subject. Although the central government can form broad guidelines, it is the state government that can pass law and implement the same. The state cabinet has approved the “Karnataka Ground Water (Regulation and Control of Development and Management) Bill, 2007, to regulate and control the development of ground water. However, it does not cover groundwater pollution. Several countries around the world, including in Asia (Japan, Thailand, Taiwan and China), have formed strict groundwater regulations. India is miserably lagging behind in recognising these critical environmental issues.
Karnataka can become the first model state in the country to bring in proper regulation on groundwater contamination, which will prevent injecting any substance into groundwater, define critical limits for a range of contaminants and hold industries responsible for polluting the public resource. It could also create provisions to educate regulatory authorities in the state and local bodies about the contamination problem and on various remedial technologies available around the world.
Unless the Karnataka government takes firm steps to protect and preserve this public resource, the state may run out of potable water within a few decades. Industrialisation and environmental protection should go hand in hand. Otherwise, future generations will hold us responsible for destroying nature.
(The writer, an agricultural microbiologist and expert on groundwater remediation, is president & CEO, EcoCycle Corporation, Japan)