Heavy metals pollute TS crops
■ The issues with crop yield are reflected in the taste, texture of the produce, its strength to fight viruses
Soil contamination with heavy metals like arsenic, chromium, copper, zinc, nickel and lead were found in high quantities in random samples collected from the northern Telangana region, according to a study published in Journal of Geosciences. There are 12 districts in north Telangana — Adilabad, Komaram Bheem, Jayashankar, Jagtial, Kamareddy, Karimnagar, Mancherial, Siddipet, Nirmal, Nizamabad, Peddapalli and Rajanna.
The presence of heavy metals in the soil showed that the index of geo-accumulation (the presence and intensity of contaminant deposits in the soil) over the years and the ecological risk index(amount of pollutants and sediments in the soil and its affects on human, animal, bird and other forms of life) showed a very high concentrations of these metals in the soil in 93 per cent of soil samples taken from these districts. A total of 150 samples were collected from various districts. The samples showed that the concentration was higher than the acceptable threshold value of 1.0 E -04 indicating a significant carcinogenic risk according to the study.
Dr M. Uma Devi, director, Water Technology Centre at the Professor Jayashankar Telangana State Agricultural University (PJTSAU), explains that “heavy metals in the soil accumulate over the years and it has been found that the crops resist it for a very long time. But if the load continues to be high, then the stalk, leaves and the flower are affected. It is a long-term effect and over the years we are now seeing issues in the yield of the crops.”
The issues with crop yield are reflected in the taste and texture of the produce and also its strength to fight the various viruses and worms that affect it. An expert in the government’s department of horticulture explained, “We have asked farmers to check on the quality of the irrigation water. With industrialisation and human habitats being close to farm lands, micro-plastics, cleansing chemicals and detergents are making their way into the lakes and rivers as they are not treated properly. This water is then used for irrigation. If the water has higher concentrations of metals, the soil contamination occurs. The insult effect of higher concentration levels can range between three to five years due to rapid and unplanned urbanisation.”
Farmers have also been using compost from the Jawaharnagar dump yard where the composting treatment has not been up to the mark. A senior official of government department working in Telangana State Pollution Control Board explained, “Various companies are selling the packets of compost but it is one material only, sourced from urban dumping yards. There is never any testing done to assess the metal content in the compost. In some cases we have found that even organic manure has a high quantum of heavy metals. The biggest worry is lead from batteries mainly from car servicing centres which make their way into water sources and are the biggest polluting agent.”
Apart from this pesticides, fertilisers, industrial chemicals and untreated sewage are major causes of contamination.
Soil is stated to be the universal sink, bearing the greatest burden of environmental pollution.
HEAVY METALS in the soil accumulate over the years and it has been found that the crops resist it for a very long time. But if the load continues to be high, then the stalk, leaves and the flower are affected. It is a long-term effect and over the years we are now seeing issues in the yield of the crops.
— DR M. UMA DEVI director, Water Technology
Centre at PJTSAU