Molluscan Shell Dissolution from the Poovar Region, Arabian Sea Coast, India: Implications on Environmental Health

Dissolution of the molluscan shells from Poovar estuary, implying the environmental health is the foci of the present study.Twelve samples were collected from the study area, eleven were grab samples and the core sample was retrieved from the spo-radic mangrove area. The predominant mangrove species in the Poovar region is Avicennia marina. The primary objectiveof the study was to ascertain the behavioural changes of molluscan shell with respect to the shifts in the sediment textureand nature. The examination of the grab sample focuses on the energy conditions that existed in the during the time ofdeposition. The sediments from the Poovar mangrove, Poovar lake, Poovar estuary, and Neyyar river display both individ-ual and collective environmental characteristics. Within the phylum Mollusca, four major genera were examined: Villorita,Crassostrea, Ostrea and Tibia. The distribution of microfossils is limited, except for a single broken specimens of Ammoniadentata, which is of ex-situ origin and transported to the mangrove environment from marine waters. In Poovar region themangroves mainly disappearing due to human activity, which is aided by fluctuations in energy condition of deposition andsea level variations. The minimal microfossil numbers are associated with the high dynamicity of the area and the mol-luscan shell dissolution was related to anthropogenic impact of tourism, fuel discharge urbanization in upper stream banksand with the coastal changes. Along with anthropogenic distubances, the dissolution in molluscan shells is accelerated dueto the excessive organic matter accumulation in the stream bed from the land vegetation. The excessive inputs of floral debrisof terrestrial origin is having an impact on the shift in the environmental parameters (pH, salinity, temperature, oxygenavailabilty and CaCO3 concentration) in the region.