Indian coastal waters: a concoction of sewage indicator bacteria! An assessment on recreational beaches

• Published in: Environmental monitoring and assessment Vol. 193; no. 7; p. 455
• Main Authors: Begum, Mehmuna, Kumar, C. Saravana, Naik, Subrat, Pradhan, Umakanta, Panda, Uma Sankar, Mishra, Pravakar
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.07.2021; Springer Nature B.V
• Subjects: Atmospheric Protection/Air Quality Control/Air Pollution; Bacteria; Beaches; Biochemical oxygen demand; Coastal management; Coastal water quality; Coastal waters; Coastal zone management; Coliforms; Dilution; E coli; Earth and Environmental Science; Ecology; Ecotoxicology; Environment; Environmental Management; Environmental monitoring; Environmental science; Faecal coliforms; Fecal coliforms; Fisheries; Household wastes; Industrial wastes; Microorganisms; Monitoring/Environmental Analysis; Oxygen; Oxygen demand; Oxygen requirement; Pathogenic bacteria; Phosphates; Pollution control; Qualitative analysis; Quality assessment; Quality control; Rain; Rainfall; Recreation; Recreational use; River mouth; River mouths; Sewage; Sewage bacteria; Total oxygen demand; Water monitoring; Water quality; Water quality assessments; Water quality management; India; Recreational beach; Faecal coliforms; Coastal waters; Vibrios; Pathogenic; India
• ISSN: 0167-6369; 1573-2959
• DOI: 10.1007/s10661-021-09244-2

Coastal water quality assessment is important to maintain a healthy environment for various uses including fisheries and recreation. Microbial populations are used as biological indicators of contamination to monitor water quality and are considered by the government to be one of the critical features for issuing safety guidelines. Different bacterial groups (pathogenic, vibrio and faecal) from five major recreational beaches of Chennai, India, were monitored for the assessment of coastal water quality. Faecal coliforms (FC) were high at all the beaches, with up to 4.2 × 10 5  CFU/mL and exceeding the normal standard limits of 100 CFU/100 mL set by the Central Pollution Control Board (CPCB) of India. Rainfall was found to have a role in the variability and distribution of indicator and pathogenic bacteria. The seasonal dry period witnessed elevated FC, while dilution in the wet period reduced Escherichia coli –like organisms (ECLO). High microbial counts were detected near the beach situated close to the river mouth, mainly due to discharges of untreated domestic sewage and industrial wastes. Similarly, the biological oxygen demand (BOD) was also high, 0.32 to 10.32 mg/L. Dissolved inorganic nitrogen (DIN) ranged from 2.21 to 134.53 μmol/L and inorganic phosphate (IP) ranged from 0 to 57.53 μmol/L. These values indicated the presence of significant untreated sewage in the coastal water. This study revealed that Chennai coastal waters carry high levels of faecal and pathogenic bacteria, detrimental for recreational and other contact activities. The quantitative and qualitative analyses will be useful for modelling and prediction of coastal water quality and management of other recreational beaches in India.