Kaveri pollution report as per journal of Himalayan Ecology and Sustainable Development

This report, published in the Journal of Himalayan Ecology and Sustainable Development (2020), examines heavy metal contamination in the Cauvery River across the Erode, Salem, and Namakkal districts of Tamil Nadu.

Study Overview

The research focused on ten heavy metals: mercury (Hg), cadmium (Cd), arsenic (As), lead (Pb), chromium (Cr), nickel (Ni), selenium (Se), copper (Cu), zinc (Zn), and iron (Fe). Water samples were collected from four specific sites along the river during the post-monsoon (December 2019) and monsoon (August 2020) seasons to assess the impact of industrial effluents and anthropogenic activities.

Sampling Sites and Industrial Sources

Four study areas were selected based on their proximity to industrial hubs:

Site I (Mettur, Salem District): Near thermal power stations, steel plants, and cement factories.
Site II (Kumarapalayam, Namakkal District): A major textile and powerloom hub with numerous dyeing industries.
Site III (Agraharam, Erode District): Home to leather, garment, textile, and chemical industries.
Site IV (Pallipalayam, Namakkal District): Contains spinning and weaving mills, paper industries, and tanneries.

Key Findings and Concentrations

The study utilized an Atomic Absorption Spectrophotometer (AAS) to measure metal levels and compared them against World Health Organization (WHO) 2017 standards.

Exceeding Limits: Chromium and lead were found across all studied areas in both seasons. Concentrations of lead, cadmium, arsenic, chromium, nickel, and selenium frequently crossed permissible limits.
Within Limits: Mercury, copper, zinc, and iron levels generally remained within the safe limits set by the WHO across all studied sites and seasons.
Mean Concentration Order (Post-Monsoon): Zn (1.375) > Fe (0.1525) > Cu (0.125) > Cr (0.0825) > Pb (0.0575) > Ni (0.0325) > As (0.02) > Se (0.0175) > Cd (0.00575) > Hg (0.00125) mg/l.
Mean Concentration Order (Monsoon): Zn (1.205) > Fe (0.0625) > Pb (0.0325) > Cr (0.02775) > Cu (0.02625) > As (0.01875) > Se (0.0095) > Cd (0.00425) mg/l.

Site-Specific Contamination

Site I was primarily polluted by effluents from power plants and steel factories, showing high levels of Pb, As, Se, and Cd.
Site II showed contamination from dyeing industries, notably Pb, Cr, and Cd.
Site III was dominated by waste from leather and chemical industries, resulting in high Pb, Cd, and Cr.
Site IV was the most heavily contaminated site, showing significant levels of Pb, Cd, As, Cr, and Ni during the post-monsoon season.

Health and Environmental Implications

The report highlights that the presence of these metals is a serious environmental concern due to their toxicity and ability to bioaccumulate in living organisms. Non-essential metals like lead and cadmium pose extreme risks to human health even at low exposure levels, potentially causing renal failure, nerve inflammation, and carcinogenic effects.

Conclusion and Recommendations

The authors conclude that the Cauvery River is significantly contaminated by industrial and domestic sewage. They recommend:

Compulsory Treatment: All industrial and municipal wastewater must be treated before being discharged into the river.
Public Awareness: Educational campaigns should be launched for industrial workers and local residents regarding the toxic nature of these metals.
Regular Monitoring: Continuous assessment of river water quality is necessary to protect the populations that depend on the river for drinking and fishing.