A report by the Central Pollution Control Board (CPCB) has revealed heavy metal contamination in exceeding limits in Edayattuchal and Chakkarachal paddy fields in the Edayar industrial region here.
The detailed assessment carried out by the Regional Directorate (South) of the CPCB stated that the now defunct Edayar Zinc Ltd. (formerly Binani Zinc Ltd.) was responsible for causing the contamination. The remediation work may be executed by the industry as per the detailed project report prepared by the Central board, it said. The report has been filed before the Southern Bench of the National Green Tribunal, which had issued orders earlier to ascertain the source of contamination of Edayattuchal and Chakkarachal paddy fields.
Samples were taken by the research team from 115 soil boreholes, 11 monitoring wells, nine sediment boreholes, and 15 open wells. Heavy metals that include zinc, iron, cadmium and chromium in soil were exceeding the screening criteria, mainly within the southern portion of the Edayattuchal and Chakkarachal paddy fields. No soil impact is identified within the residential area adjacent to the paddy fields, it said.
Heavy metals were identified in groundwater exceeding the screening criteria and localised within the boundaries of the paddy fields. The jarosite storage facilities located within the northern portion of the industry remain the primary source of contamination. The secondary potential sources include the groundwater contaminated due to leaching from primary sources, contaminated soil and sediments in flooded/marshy zones and contaminants distributed owing to flooding. Quoting local residents, the report said that unauthorised discharge of effluents was through a drain on the southern extreme side of the Edayattuchal paddy fields. Discharge of effluents was also reported within the Chakkarachal paddy fields. Surface water discharge was observed on the southern portion of Edayattuchal, originating from the industrial area. The exact origin of the effluent discharge was not traced, it said. The company authorities had earlier requested the tribunal to fix the liability only on the basis of proper evidence as they were not the only industry in the area.
