Soil contamination, a new problem in Visakhapatnam

Visakhapatnam: Vizag city has long been battling with air pollution. The growing air pollution levels due to industrial emissions as well as effluents, are now resulting in  soil pollution. Two recent studies of Andhra University found heavy metal contamination in the soil in parts of Vizag. The researchers collected samples from the Old town, Gnanapuram, Gajuwaka industrial region, etc. and found those areas were subjected to considerable soil degradation with heavy metals such as lead, copper, chromium, zinc, etc. For example, the mean values of lead level in the soils of Old Town and Gnanapuram were 43.77 mg/kg and 30.21 mg/kg against the normal 25 mg/kg.

According to experts, over time, the heavy metals in the soil can leach into the groundwater as well increase input to the food chain, putting human health at risk. They attribute the soil contamination to the industrial effluents, often non-treated, entering the soil. Even though many of these elements are biologically essential, the accumulation of toxic metals will reduce the soil fertility. This will affect both vegetation and biodiversity of that particular area.

Speaking to this correspondent, Dr B. Sujatha, a professor at the Department of Botany and lead researcher of the two studies, explained; “Our first study area was Old town and Gnanapuram, which have been severely threatened by the growing levels of heavy metal pollution due to the discharges from the industries in the vicinity. Our study found that the Old Town area and Gnanapuram were under a considerable degree of soil contamination. The heavy metals in the soil samples include copper, nickel, lead, zinc, etc.,” said Dr Sujatha.

The second study had focused on the heavy metal content in the industrial areas of Visakhapatnam. The collected soil samples were air-dried and sieved into coarse and fine fractions. Analysis of heavy metals in these soil samples showed higher levels of heavy metal concentration of: mercury, cadmium, lead, chromium and arsenic. “Cleaning the contaminated soil is not only a daunting task, but also an extremely expensive and difficult endeavour. Once the heavy metals are allowed to contaminate the environment, they will persist and continue to remain in the environment for a long span of time,” said Dr Sujatha.