Heavy toxic metals in Ganga contaminate food chain too

VARANASI: Prime Minister Narendra Modi might be startled to know that despite his clarion call to restore the pristine glory of the Ganga, the river in Kashi is not only polluted with municipal wastewater but also with toxic heavy metals that have started contaminating the food chain. The PM is arriving here on a two-day visit on Friday.
Banaras Hindu University’s environment scientists have detected presence of toxic heavy metals in Ganga’s water and deposition in river sediments.Besides, metal bio-accumulation has been found in fish too. In fact, the study indicates that highest accumulation of metals was found in fish muscle followed by gills. The least accumulation was found in liver. This poses a grave threat as fish muscle is the principal source of metal exposure to human as Mangur (the fish used in the study) is an integral part of non-vegetarian diet of population living in the Ganga basin.
Varsity’s environment scientist and expert member of the National Ganga River Basin Authority (NGRBA) Prof BD Tripathi said, “No guidelines have been provided regarding the concentration of heavy metals in the river sediments in India. Such a guideline is urgently required.” Incidentally, Prof Tripathi undertook a study to assess concentration of heavy metals in Ganga’s water and river sediments.
Prof Tripathi said that the study found the river water laced with toxic heavy metals, including Manganese, Iron, Nickel, Copper, Zink, Cadmium, Lead, Titanium and Vanadium. For the study, samples of river water and sediments were collected from 15 sampling points located near the Samne Ghat, Ravidash Ghat, Assi Ghat, Ganga Mahal Ghat, Chetsingh Ghat, Harishchandra Ghat, Shivala Ghat, RP Ghat, Manikarnika Ghat, Bhosle Ghat, Panchaganga Ghat, Teliyanala Ghat, Rajghat I, Rajghat II, and Ganga-Varuna confluence,
“Though the concentration of these metals, except lead, was found to be within the permissible limit, the process of biological magnification could increase the concentration of these chemicals manifold due to their persistent nature,” he said adding that deposition of these metals was harmful to the health of the river and the humans.
He pointed the sewer systems of Varanasi as the major source of discharging toxic industrial waste in Ganga. “Concentration of these metals is also found in river sediments,” he claimed and added that anthropogenic factors (discharge from agriculture, domestic and industrial sectors) were the prime cause of river pollution. Industrial effluents directly get mixed into city sewage and were ultimately discharged into the river due to unavailability of metal removing technologies, he added.