Down to Earth (DTE) 1-15 Feb 2020 Part 2 (Download PDF)

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Arsenic Contamination in Groundwater

  • One of the most crippling issues.

  • Central Ground Water Board (CGWB) Report-21 states across the country have pockets with arsenic levels higher than the Bureau of Indian Standards’ (BIS) stipulated permissible limit of 0.01 mg/l.

  • First of all arsenic contamination was officially confirmed in West Bengal in 1983.

  • Arsenic crisis has increased Modern Groundwater-Based Irrigation Techniques and a Gradual Shift from a Rainfed Crop to Multiple Irrigated Crops.

  • Permissible exposure limit for arsenic is no greater than 10 micrograms of inorganic arsenic per cubic meter of air.

The U. S. Environmental Protection Agency (U. S. EPA)

  • An arsenic maximum contaminant level (MCL) for public water supplies at 0.010 mg/L.

  • Equivalent to 0.010 parts per million (ppm), 10 micrograms/liter (µg/L), or 10 parts per billion (ppb).

Worst Affected States

  • Uttar Pradesh

  • Bihar

  • Jharkhand

  • West Bengal

  • Assam

National Rural Drinking Water Programme (NRDWP) of the Ministry of Jal Shakti (MOJS) -People at Risk

  • 9.6 million People in West Bengal.

  • 1.6 million in Assam.

  • 1.2 million in Bihar.

  • 0.5 million in Uttar Pradesh.

  • 0.013 million in Jharkhand.

Arsenic levels in various states

Arsenic levels in various states

Arsenic levels in various states

Hazardous Health Effects of Arsenic

  • Cardiovascular disease.

  • Hearing loss.

  • Lung fibrosis.

  • Developmental effects.

  • Cancer-skin, lung, liver, kidney, bladder.

  • Coronary heart disease.

Arsenic Sources and Transfer

Arsenic Sources and Transfer

Arsenic Sources and Transfer

Prevention and Control

  • Installing arsenic removal systems either centralized or domestic.

  • Substitute high-arsenic sources, such as groundwater, with low-arsenic, microbiologically safe sources such as rain water and treated surface water.

  • Blend low-arsenic water with higher-arsenic water.

  • Adding lime or coagulants to water.

  • Using an ion exchange process.

Presence of Arsenic in Nature

  • Air

  • Water

  • Soil

  • Vegetables

  • Fruits

  • Juices

  • Rice

  • Grains

  • Seafood

  • Meat

  • Wine

Tree Rings and the Global Warming

  • Scientists at the University of Arizona are using tree rings to study centuries of drought conditions in the Colorado River Basin.

  • Long term changes in weather conditions and alterations in the frequency or strength of natural events.

  • Trees are sensitive to local climate conditions, such as rain and temperature.

  • Tree rings usually grow wider in warm.

  • Thinner in years when it is cold and dry.

  • Light-colored rings represent wood that grew in the spring and early summer.

  • Dark rings represent wood that grew in the late summer and fall.

Birbal Sahni Institute of Palaeosciences, Lucknow

  • Used annual rings of 300-year-old Himalayan cedar trees from Kumaon and Garhwal regions.

  • Developing drought records in the Himalayan region between 1720 and 2012.

The annual Tree Rings

The annual Tree Rings

The annual Tree Rings

Hurricanes and the Tree rings

Hurricanes and the Tree rings

Hurricanes and the Tree rings

Community Based Conservation

  • A conservation movement that emerged in the 1980s.

  • Through escalating protests and subsequent dialogue with local communities.

  • To guide tourists in the Manas National Park former poachers have been recruited by community led conservation organisations.

  • Bodoland insurgency in the Baska district of Assam.

  • MMES along with recently added 17 other such organisations under the banner of United Front for Conservation of Nature are bringing about a refreshing change in wildlife management.

  • MMES is one of the numerous dedicated community-based organisations (CBOs) that have been formed since the Bodo Peace Accord in 2003 to protect Manas.


  • To better recognize local people’s knowledge.

  • Interests.

  • Roles and rights in natural resources management.

  • Mutual trust.

  • Sharing of management power and responsibility.

  • Local and traditional ecological knowledge.

CBC Benefits

  • Greater development.

  • More jobs.

  • Better governance.

  • Healthier lands.

  • Thriving wildlife.

Waived off Environmental Clearance for Onshore and Offshore

  • India has waived off environmental clearance for onshore and offshore gas as well as oil exploration projects.

  • On imported crude oil, can cause serious damage to islands, fishing areas, breeding grounds and migratory routes.

  • 2018 - 19 India meets 83.8 per cent of its crude oil needs through imports.

  • 2014 - 15 import was 78.3%.

  • The production of crude oil and natural gas in India has gone down.


  • NGT Stands for National Green Tribunal.

  • CPCB Stands for Central Pollution Control Board.

  • CPCB has been recently directed by the NGT after finding huge gaps in its reports filed on the compliance of pollution abatement measures by different states and Union Territories as earlier ordered.

  • CPCB has also been directed to obtain data pertaining to the municipal waste generated, segregated, treated and on the over 4,000 legacy dump sites that need remediation.

  • Action plans for containment of air pollution in 122 cities where air quality is poor.

  • The extent of remediation measures taken towards restoration of 351 polluted river stretches.

  • NGT was established under section 3 of the National Green Tribunal Act, 2010.

  • NGT was established with an aim to provide speedy environmental justice along with reducing the burden of litigation in the higher courts.

  • CPCB is a statutory organisation under the Ministry of Environment, Forest and Climate Change (Mo. E. F. C) being established in 1974 under the Water (Prevention and Control of pollution) Act, 1974.

  • CPCB advices the government on any matter concerning the improvement of the quality of air and prevention control.

Know the MCQs

  • In the Dharmapuri District of Tamil Nadu a cooperative in drought-prone shows forestry and rainwater harvesting can be profitable livelihoods. The 100-hectare green patch, with several rainwater harvesting structures, has over 100,000 bamboo and aloe vera plantations for commercial cultivation.

  • 2019 was the second warmest year since 1850.

  • India has 134 contaminated hazardous sites and 192 “probable” contaminated hazardous sites.

  • At Amer Fort in Rajasthan animal cruelty is at the heart of the framed elephant rides.

  • Cyclone Mekunu in May and Cyclone Luban in October caused heavy rain in the Arabian Peninsula and created lakes in deserts.

  • Locusts travel and eat only during the day, consuming food equal to their weight in 24 hours.

- Published/Last Modified on: March 4, 2020


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