Abstract
Most riverine mangroves (characterized by salinity fluctuations and tidal inundations), are seriously threatened by metallic pollution. Whether differences in salinity and tidal effects along the river continuum can affect metallic bioaccumulation and the biomagnification of species is still unknown. Bivalves are representative sessile inhabitants in mangrove ecosystems, with a high capacity to bioaccumulate metallic contaminants. The present study used two bivalves, Meretrix lusoria and Mytilopsis sallei, to monitor inter-site changes in metallic contamination and assess the associated ecological impacts along the tidal gradients of riverine mangroves. The concentrations of a total of six metals (Cr, Ni, Cu, Zn, Cd and Pb) in M. lusoria and M. sallei, collected at three different sites along Danshuei Riverine Mangrove, were investigated. The metallic concentrations of the whole soft body of the studied bivalves, and the associated surface sediment from each site, were analyzed using inductively coupled plasma mass spectrometry (ICP-MS) to determine the inter-site effects on the bioaccumulation and biomagnification of metallic contaminants in bivalves. There are increasing concentrations of four metallic contaminants, Zn, Cr, Cd and Cu, in the seaward direction of the bivalves. The increasing mean metallic concentrations along the seaward direction may be the effect of salinity, further decreasing the rate of the elimination of these metals, thus resulting in a net increase in metallic contaminants. Our results clearly show prominent inter-site changes in the metallic burdens of bivalves in our study on riverine mangrove ecosystems associated with different levels of bioaccumulation and biomagnification of metallic contaminants. Thus, it is important to monitor multiple sites along the dynamic environment of riverine mangroves in order to gain a good understanding of the ecological impact of metallic pollution risks. The present findings provide important evidence of the use of simple indices to assess the ecological impacts of metallic pollution in riverine mangroves.
Highlights
Mangroves are important, unique estuarine and coastal ecosystems that possess high bio-productivity, waste purification capacity and carbon sequestration potential, serving as important nursing grounds for fish and providing many other ecological functions and recreational services [1,2].the ecological environments in mangroves can seriously deteriorate due to pollution and habitat degradation from the proliferation of human activities [2,3,4,5]
Clear inter-site trends were observed for the metallic concentrations of sediments along the Danshuei Riverine Mangrove, where all studied metal contaminants, except Ni, showed the highest concentrations at WG, and sediment metallic concentrations at JZC were slightly lower than WZW
Though long-term data about the changes in the faunal community structure, the displacement of stress-sensitive native species by pollution-tolerant exotic species and the ecotoxicological responses of aquatic biota in the Danshuei Riverine Mangrove ecosystem have not been well documented due to a lack of systematic biological monitoring, the pollution risk associated with the metallic pollution of Danshuei Riverine Mangrove has aroused public concern in recent decades [38,39]
Summary
Unique estuarine and coastal ecosystems that possess high bio-productivity, waste purification capacity and carbon sequestration potential, serving as important nursing grounds for fish and providing many other ecological functions and recreational services [1,2]. The ecological environments in mangroves can seriously deteriorate due to pollution and habitat degradation from the proliferation of human activities [2,3,4,5]. Expanding industrial, agricultural and municipal development leads to the production and discharge of waste rich in metallic contaminants into adjacent mangrove ecosystems. In the face of extensive urbanization and ever-increasing metallic pollution due to economic development, mangrove biota could be exposed to unprecedented effects due to toxicity from metallic contaminants [15,16]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
