Assessing Impacts of Metallic Contamination along the Tidal Gradient of a Riverine Mangrove: Multi-metal Bioaccumulation and Biomagnification of Filter-Feeding Bivalves

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.

Mangrove Trace Metal Biogeochemistry Response to Global Climate Change

“…No study, to our knowledge, has directly related changes in bioaccumulation rates in mangrove organisms, notwithstanding the notable influence of environmental factors like tidal variation, temperature, salinity, and concentrations of organic matter and nutrients, which are eventually affected by climate change (Guinot et al, 2012;Yam et al, 2020). Yet, the extent of metals uptake and bioaccumulation by organisms varies and potentially deleterious effects have been found in mangrove Crustaceans (crabs, shrimps), Molluscs (bivalves, mussels, oysters), and fishes, potentially affecting top consumers like birds and eventually humans (Silva et al, 2001;Ruelas-Inzunza and Páez-Osuna, 2008;De et al, 2010;Yam et al, 2020;Sangur et al, 2021).…”

Remediation of heavy metal polluted waters using activated carbon from lignocellulosic biomass: An update of recent trends

“…Moreover, heavy metal-polluted sediments are indicated to threaten creatures such as worms, crustaceans, and insects in the benthic environment, even they could kill the benthic organisms, resulting in a significant reduction of the food availability for larger animals (Bere et al, 2016) (Akindele et al, 2020). Besides, when larger animals feed on heavy metal-contaminated organisms, these heavy metals enter their bodies, causing the bioaccumulation and biomagnification process that threatens their lives (Ali and Khan, 2019) (Yam et al, 2020).…”

In situ Concentration and Adsorption Characteristics of Cu(II) and Pb(II) in Bed Sediments of River Niger in Lokoja Area, Nigeria

“…Heavy metals have a tendency to bioaccumulate and biomagnify along the food chain, and persist in the aquatic environment (Yam et al, 2020), and toxic to humans, so they are considered serious pollutants. Due to industrial production (Lu et.…”