Groundwater in at least 30 of the 36 districts in Maharashtra has presence of heavy metals, such as lead and nitrate, over the maximum acceptable concentration, a recent study by the Central Ground Water Board (CGWB) has found. The study has also indicated a decline in groundwater level across the state.
Ingestion of such heavy metals can lead to learning disabilities in children, besides methemoglobinemia or “blue baby” disease — a blood disorder, experts say.
To assess the decline and rise in water level on a long-term basis, the CGWB conducts groundwater survey four times a year on regional scale through a network of observation wells in the country. In a recent assessment of pre-monsoon water level for 2018 — the data for which has been compared with the decadal average (2008-2017) water level — the Board has found a decline in Maharashtra’s groundwater level in around 53 per cent of the monitored wells. There has been a rise in the water level in the remaining 47 per cent of the monitored wells. The national average stands at a rise in 48 per cent of monitored wells and decline in 52 per cent.
The CGWB monitored a total of 1,632 wells in Maharashtra, of these 774 showed an increase, while 857 showed a decline in groundwater level over the decades average. In one, the level remained unchanged.
The study also noted nitrate contamination in at least 30 districts and presence of lead in about 19 districts across the state. Nitrate makes its way into groundwater primarily from fertilizers, septic systems and manure storage or spreading operations. Ingestion of such metals can damage the brain and nervous system and cause learning disabilities in children.
Studies have also indicated severe over-extraction of water in the state. As per the fourth Minor Irrigation Census, conducted in 2006-07, there were over 21.5 lakh wells and borewells across Maharashtra. The number of such wells, as per the first Census conducted in 1986-87, was just 5 lakh — indicating a four-fold increase in a period of less than 30 years.
To check unregulated extraction of groundwater from areas facing severe scarcity, Maharashtra Groundwater (Development and Management) Act, 2009, was formulated. The Centre Central Ministry of Water Resources, River Development and Ganga Rejuvenation has now proposed that water conservation fee would be levied for use of groundwater depending on the category of area, type of industry and quantum of withdrawal.