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| Abstract Submission No. | ABS-2022-09-0364 |
| Title of Abstract | Current status of coastal water quality: A comprehensive assessment of Chennai metropolis region, India |
| Authors | PRAVAKAR MISHRA*, Subrat Naik, Mehmuna Begum, Uma Kanta Pradhan, Debasmita Bandyopadhyay, Athan Vashi, D Sathish Kumar, Uma Sankar Panda, M V Raman Murthy |
| Organisation | National Centre for Coastal Research (NCCR) |
| Address | NIOT Campus, Pallikaranai, Chennai Tamilnadu, Tamil Nadu, India Pincode: 600100 Mobile: 9444054364 E-mail: mishra@nccr.gov.in |
| Country | India |
| Presentation | Oral |
| Abstract | Coastal water is prone to contamination from a variety of point and non-point sources, largely due to several anthropogenic activities or mismanagement of resources on the land side. Several studies have documented that environmental catastrophes such as the formation of hypoxia zones, frequent incidences of toxic blooms, instances of mass fish kill, and ocean acidification are increasing globally. During the last decade, several episodic events such as the occurrence of coastal foams, algal blooms, fish kills, and oil spills were encountered along this region. With this backdrop, this study intends to assess the coastal water quality adjoining the Chennai metropolis region to suggest appropriate management strategies. Long-term water quality data suggest a high concentration of nitrogen ( NO3 - 32.35 µM, NH4 - 440.5 µM) and phosphate (58.1 µM) in the coastal water. The distribution of nutrients demonstrates seasonal and spatial variation mainly at the river inlets and shore region. Incidents of sea foaming (8 times), algal blooms (7 times) are regular events that usually occur after a heavy spell of rain combined with rough sea and higher phosphate load through the river and land runoff. Several harmful algal blooms (HABs) of diatom (Asterionellopsis glacialis), green alga (Chlorella salina), cyanobacteria (Trichodesmium erythreaum), and coccolithophore (Phaeocystis sp.) have been frequently encountered. Fish mortalities of Mugil cephalus, Chanos chanos, and Tilapia mossambica adjacent to the river inlet were reported. Low salinity (3.63 PSU), hypoxia (1.73 mg L-1), and heavy metal toxicity (Pb = 28.6 and 87.9 mg Kg-1 and Cd =2.13 and 4.3 mg Kg-1in fish tissue and sediment respectively) might be attributed to the fish kill incidents. High abundance of pathogenic bacteria Vibrio cholerae (6.48 ÿ105 CFU/mL), total heterotrophic bacteria (1.13ÿ107 CFU/mL) and pollution indicator bacteria such as Total coliforms (9.1 ÿ105 CFU/mL), Fecal coliforms (1.6ÿ105 CFU/mL)and Escherichia coli (8.5 ÿ104 CFU/mL) were also recorded. Untreated sewage effluents into the coastal water elevate nutrient and microbial loads. These episodic events are a warning call to the coastal stakeholders of Chennai metropolis that the coastal water is in an unpleasant state and demands immediate and appropriate attention in improving the existing sewage treatment capabilities and solid waste management. Keywords: Coastal water quality; Seafoam; Algal blooms; Fish kills; Chennai metropolis; India |