A study conducted by the CSIR-Central Salt & Marine Chemicals Research Institute (CSIR-CSMCRI), Bhavnagar, has found the marine ecosystem surrounding Tata Chemicals Limited’s (TCL) treated wastewater discharge point at Mithapur to be healthy, stable and productive. The assessment shows that the coastal ecosystem continues to maintain good environmental health. In particular, water and sediment quality parameters remained within natural ranges, while the area supported diverse marine life, healthy mangroves and a wide variety of resident and migratory birds.
Natural Marine Processes Sustain the Coastal Environment
The CSIR-CSMCRI study indicates that decades of industrial operations and treated wastewater management have co-existed with the sensitive coastal environment. Importantly, natural marine and tidal processes continue to predominantly govern local environmental conditions. Moreover, the diversity indices recorded during the assessment indicate healthy vegetation communities, with no evidence of environmental degradation.
637 Birds Across 40 Species Recorded
The study recorded 637 birds representing 40 species, including migratory species that use the Central Asian Flyway. This highlights the ecological importance of Mithapur as a stopover and feeding area for migratory birds. Interestingly, the sampling station closest to the discharge point recorded the highest bird abundance during the study. The survey also identified approximately 250 Greater Flamingos at this location. The findings further indicate that the local mudflats continue to provide important feeding grounds for a range of bird species.
Healthy Mangroves Support Coastal Biodiversity
The assessment also found healthy mangrove stands along the Mithapur coast, with Avicennia marina as the dominant species. These mangroves play an important ecological role by stabilising the shoreline and providing habitat for coastal organisms. Consequently, their continued health contributes to the overall resilience and biodiversity of the coastal ecosystem.
Diverse Plankton Indicate a Productive Marine Food Web
The marine biological assessment identified a diverse plankton community comprising 22 phytoplankton species and 23 zooplankton species. This diversity indicates a balanced and productive marine food web, as phytoplankton and zooplankton form an important foundation of coastal marine ecosystems.
Seawater Quality Remains Within Healthy Ranges
The study assessed several key seawater quality parameters, including pH, salinity, dissolved oxygen (DO) and biochemical oxygen demand (BOD). According to the report, these parameters remained within ranges typically associated with a healthy coastal marine environment. Together with the water, sediment and biological observations, the results point to stable environmental conditions around the study area.
Biennial Monitoring Tracks Environmental Impact
The assessment forms part of the biennial monitoring requirements associated with the approval of the treated wastewater discharge pipeline project. Experts conducted field studies in December 2025 and May 2026, examining water quality, sediment quality, marine biology, floral diversity and avifauna. Released in August 2026, the report represents the first assessment submitted under the ongoing monitoring framework. The study covered the coastal environment within a 10-km radius of the discharge point in the Gulf of Kutch.
CSIR-CSMCRI’s Expertise in Marine Ecology
The CSIR-Central Salt & Marine Chemicals Research Institute (CSIR-CSMCRI) is a national constituent laboratory of the Council of Scientific & Industrial Research (CSIR), Government of India. Based in Bhavnagar, Gujarat, the institute is a National Accreditation Board for Testing and Calibration Laboratories (NABL)-accredited testing laboratory. Its research and monitoring activities cover areas including marine ecology, salt technologies and environmental monitoring. As per the press release, the CSIR-CSMCRI assessment indicates that the Mithapur coastal ecosystem continues to support healthy marine biodiversity, mangroves and bird populations, while key water and sediment quality parameters remain within natural or healthy coastal ranges.
