Heavy Metal Contamination, Nutrient Dynamics and Microplastic Pollution in Surface Sediments of Saint Martin’s Island and Teknaf Coast for Ecological Health Perspective

Author: Onamika Rahman, Imtiaz Ahmed Sakib, Adiba Mosharraf, Ferdousi Begum, Farhana Akter, Abu Hossain Rakib, Md. Abu Bin Hasan Susan
DOI: doi.org/10.70279/bmj-v2-1102

Saint Martin's Island (SMI) and Teknaf Coast (TC) are environmentally significant special areas in the coastal zone of Bangladesh, although "Coastal and Marine" ecology is experiencing a growing rate of environmental degradation due to unscrupulous human manipulations. Therefore, current study was carried out on TC and SMI by evaluating various sediment quality parameters viz., physicochemical properties, concentration of nutrients and heavy metals (HMs)/minerals along with abundance of microplastics (MPs) of sediments collected in March 2022. Salinity, pH, electrical conductivity (EC), dissolved oxygen, density, total dissolved solids and total organic carbon were within the standard limit except EC. Sediments of SMI exhibited lower nutrient concentrations compared to TC, with the following order: silicate > ammonia > nitrate > phosphate > nitrite. Average type of sediment was sand in SMI, and clay was also present among the sediments of TC, based on total porosity values. Various sediment quality indicators were developed considering the observed concentrations of HMs/minerals using Inductive Coupled Plasma Mass Spectrometer. Calculated Heavy Metal Pollution Index suggested that sediments were highly contaminated. Furthermore, sediments of Uttarpara (north side) from SMI and TC were highly contaminated based on observed Pollution Load Index as well as Geo-accumulation Index. Eventually, three types of MPs including foam, fragment and fiber were found in the sediments of both areas, and among the MPs (smaller than 1 mm), fibers were the most abundant and their presence was lower in SMI compared to TC. Thus, this research helps us to understand comparative sediment quality of SMI and TC for the sake of coastal ecology of Bangladesh.