Water Pollution Due to Improper Waste Management

Real life examples of the impact of waste management on water pollution mentioned in this article are provided in my latest report Observations from India's Waste Crisis (February, 2013).

Unsanitary landfills, which are more commonly referred to as open dumpsites can contaminate ground and surface water resources when the leachate produced percolates through the soil strata into the groundwater underneath or is washed as runoff during rains. Leachate is generally a strong reducing liquid formed under methanogenic (anaerobic) conditions. The characteristics of leachate depend on the content of various constituents in the dumped waste (4).
“Studies on Environmental Quality in and around Municipal Solid Waste Dumpsite” in Kolkata, by Biswas A.K., et al. found moderately high concentrations of heavy metal in groundwater surround the dumpsite. The study found out that the groundwater quality has been significantly affected by leachate percolation.
Leachate generally contains organic chemicals formed by anaerobic digestion of organic wastes and heavy metals leached from inorganic wastes.

Percolation of leachate in to the ground from a dumpsite like this can effect the quality of ground water used by the nearby community - Pimpri Chinchwad, Maharashtra, India (Ranjith Annepu)

The heavy metals generally observed in leachate are Lead (Pb), Cadmium (Cd), Chromium (Cr) and Nickel (Ni). All these heavy metals are characterized as toxic for drinking water. Due to the reducing property of leachate, during percolation through soil strata, it reacts with Iron (Fe) and Manganese (Mn) species underground and reduces them into more soluble species, thus increasing their concentrations in groundwater (4). Such reactions when they occur, pose a serious drinking water toxic risk. These predictions are substantiated by studies which found high concentrations of Cr, Cd and Mn in groundwater due to leachate percolation. Nitrates present in the environment can also be reduced to nitrites due to leachate. Nitrites consumed through drinking water can oxidize haemoglobin (Hb) in the blood to methaemoglobin (met Hb), thereby inhibiting the transportation of oxygen around the body (4).
The study clearly establishes that unsanitary landfills in India and elsewhere are potential sources of heavy metals contamination in groundwater sources adjoining the landfills. It also points out that there is an urgent need to adopt credible solutions to control water pollution caused due to indiscriminate dumping of wastes.