KOCHI: At a time when the National Green Tribunal had directed the Central Pollution Control Board (CPCB) and the Kerala State Pollution Control Board to prepare an action plan to reduce the impact of industrial effluents in water bodies at Eloor and Edayar industrial area in Kochi, a study conducted by the School of Marine Sciences of Cusat has revealed increased heavy metal content in Kochi Estuarine system is adversely affecting the fish and aquatic organisms.
High level of heavy metals is damaging the kidney, liver, muscle, tissues and gills of fish. “The Kochi coastal zone is under increased industrial activity with over 250 large and medium industries causing heavy metal contamination leading to ecological decay in the region,” principal investigator and head of the Cusat Marine Biology, Microbiology and Biochemistry Department S Bijoy Nandan told Express. “The volume of industrial effluents discharged from the Eloor-Kalamassery industrial belt is about 260 million litres per day, much of which is directly discharged into the Periyar River from where it enters the backwaters. There is a need to study the heavy metal contamination of drinking water projects in view of the increase in renal diseases in Kerala.”
There have been frequent reports of Periyar turning red due to the release of industrial effluents. These effluents carry a huge quantity of copper, zinc, lead, iron, arsenic, cadmium and other heavy metals.
Though the Kerala Water Authority distributes water pumped from Periyar after clarification, filtration and disinfection, experts say the process is not sufficient to remove the heavy metals. So, the authorities have to improve the treatment process and ensure the tap water is safe to drink, said Nandan.
“It is true that heavy metal contamination of drinking water can cause renal diseases. There were reports blaming heavy metal contamination of drinking water for renal diseases in Japan and other countries in the past. However, we don’t have any proof to relate the increase in renal diseases in India with heavy metal contamination,” said senior nephrologist R Kasi Visweswaran. According to experts, increased presence of copper can lead to changes in haemoglobin and can be cancerous. Lead gets accumulated in the liver and kidney damaging the cells. It can affect the respiratory system and the brain cells. Zinc causes abdominal pain and vomiting.
The Cusat study found an alarmingly high concentration of metals like zinc, lead, cadmium and copper in the sediment samples collected from the Kochi Estuarine system, which would have deleterious effects on organisms and would impose serious health issues leading to bioaccumulation and biomagnification trends. The increased heavy metal content in water has led to an abnormality of the blood cells, structural changes in the gills, liver, kidney and spleen of the aquatic organisms, the report said.
The team studied the impact of contamination in pearlspot, mussels, black clam, shrimp, tiger prawn, jellyfish, copepods, and micro algae. The team prepared a definitive Water Quality Criteria for copper, zinc and lead adopting the guidelines from United States Environmental Protection Agency (USEPA). While the USEPA benchmark for permissible level of heavy metals in water bodies are 1.3 micrograms per litre for copper, 81 micrograms per litre for zinc and 8.1 micrograms per litre for lead, the concentration of these metals was 5.08 micrograms, 54.96 micrograms and 25.40 micrograms respectively.
The results of the study were published in the marine environmental research journal Elsevier. P R Jayachandran, Anu P R, Don Xavier N D and Midhun A M were the project fellows associated with the study.
The Central Water Commission had conducted a study in 2016 on the status of toxic metals in Indian rivers in 2016, which reported 38.58 micrograms of lead per litre of water in Achankovil River and 13.58 micrograms of lead per litre in Kallada River. The report said Periyar was the most polluted at six sites with high concentration of copper, arsenic, vanadium, selenium, chromium, magnesium, lithium and nickel.