Evaluation of the potential of the common cockle (Cerastoderma edule L.) for the ecological risk assessment of estuarine sediments: bioaccumulation and biomarkers

Abstract

Common cockles (Cerastoderma edule, L. 1758, Bivalvia: Cardiidae) were subjected to a laboratory assay with sediments collected from distinct sites of the Sado Estuary (Portugal). Cockles were obtained from a mariculture site of the Sado Estuary and exposed through 28-day, semi-static, assays to sediments collected from three sites of the estuary. Sediments from these sites revealed different physico-chemical properties and levels of metals and organic contaminants, ranging from unimpacted (the reference site) to moderately impacted, when compared to available sediment quality guidelines. Cockles were surveyed for bioaccumulation of trace elements (Ni, Cu, Zn, As, Cd and Pb) and organic contaminants (PAHs, PCBs and DDTs). Two sets of potential biomarkers were employed to assess toxicity: whole-body metallothionein (MT) induction and digestive gland histopathology. The bioaccumulation factor and the biota-to-soil accumulation factor were estimated as ecological indices of exposure to metals and organic compounds. From the results it is inferred that C. edule responds to sediment-bound contamination and might, therefore, be suitable for biomonitoring. The species was found capable to regulate and eliminate both types of contaminants. Still, the sediment contamination levels do not account for all the variation in bioaccumulation and MT levels, which may result from the moderate metal concentrations found in sediments, the species' intrinsic resistance to pollution and from yet unexplained xenobiotic interaction effects.

The Role of the Cephalopod Digestive Gland in the Storage and Detoxification of Marine Pollutants

“…Although demonstrated in cephalopods (e.g., Boucaud-Camou, 1968; Costa et al, 2014), the existence of specialized excretory cells is not consensual in other molluscs and their specific function in cephalopods is not well understood. There are, nonetheless, reports on changes in size and number of hydropic vacuoles of digestive gland cells of gastropods and bivalves as a result of exposure to mixed metallic and organic toxicants (Zaldidar et al, 2007; Lobo et al, 2010). …”

Organochlorine accumulation on a highly consumed bivalve (Scrobicularia plana) and its main implications for human health

“…Supplementary sediment samples were taken for determination of the total organic matter (TOM) content. Sediments were previously dried at 60°C and combusted at 500°C for 4 h (Lobo et al, 2010).…”

“…As sedentary filter-feeders, bivalves are known to be effective bioaccumulators of chemical substances (Coelho et al, 2006;Lobo et al, 2010;Cardoso et al, 2012Cardoso et al, , 2013, providing a time integrated indication of environmental contamination, as well as reliable information on the potential impact of seafood consumption on public health (Fang, 2004;Otchere, 2005). The worldwide-distributed benthic bivalve S. plana is a deposit feeding species of high commercial interest and key importance in the structure and functioning of estuarine ecosystems.…”

BIOACCUMULATION OF ORGANOCHLORINES PESTICIDES (OCP) COMPOUND IN GREEN MUSSELLS (Perna viridis) IN JAKARTA BAY

“…Hewan bivalva, seperti kerang sering digunakan sebagai bioindikator untuk memonitor pencemaran oleh senyawa-senyawa organik di kawasan pantai (Lobo et al, 2010;Cardoso et al, 2012;dan Cardoso et al, 2013). Hal ini disebabkan oleh distribusi penyebarannya yang luas, mempunyai sifat hidup menetap, mudah untuk dilakukan pengambilan contoh, di samping, mempunyai toleransi yang luas terhadap salinitas, tahan terhadap tekanan dan tingginya akumulasi berbagai bahan kimia (Andral et al, 2011).…”