Keywords: trace metals, Asiatic clams, bioaccumulation, biomonitoring, Rio de la Plata, environmental health, freshwater ecotoxicology, water pollution, Argentina
Size-related trace metal bioaccumulation in Asiatic clams (Corbicula fluminea) from the Rio de la Plata estuary, Argentina
Asiatic clams from the Rio de la Plata estuary were classified in seven Shell Length (SL) classes (6.0 ≤ SL ≤ 41.0 mm) and analysed for metals to evaluate their bioaccumulation dynamics and characterise the significance of growth-related variability potentially interfering in clam monitoring programmes. Metal concentrations were rather homogeneous (Zn: 223 ± 64; Fe: 222 ± 87; Cu: 29 ± 5.5; Mn: 20 ± 5.5; Cr: 2.9 ± 1.1; Ni: 2.5 ± 0.9; Cd: 0.7 ± 0.3 µg g−1). Regression analyses between metal concentrations and clam size, SL, soft tissues dry weight (BW) displayed different patterns: decreasing (Fe-Cd-Cr-Zn), independent (Mn-Ni) and increasing (Cu) concentrations with size, representing accumulation strategies from regulation to net accumulation. Covariance analyses of metal concentrations-SL/BW indicated no significant seasonal differences. Metal particulate phase speciation in the RLP, clam depuration and suspended particulate size-fractionation assays suggest that fine suspended particles are the prevailing clam metal mode of uptake.