RESUMO
Trace metals concentrations along with stable isotopes ratios were measured in marine algae, sea grass, sponges, echinoderms, mollusks, crustaceans, fishes, and the California sea lion, to assess the bioaccumulation potential and detect potential risks for top predators off Bahia Magdalena, Mexico. We assessed the trophic magnification factor (TMF) to determine the potential for biomagnification of 11 trace metals. The concentrations of Fe and Zn were one order of magnitude higher than all other metals. Concentrations of As, Cu, Cd, Co, Cr, Fe, Mn and Ni correlated negatively with trophic level, supporting trophic dilution (TMF < 1, p > 0.05), while Zn and Hg had significant trophic magnification (TMF > 1, p < 0.05) when assessing only the benthic-pelagic foodweb. This research provides a baseline concentration of metals in multiple species, metal-specific foodweb bioaccumulation and biomagnification of mercury, underscoring the key role of the macrobenthic community as biovectors for trophic transfer of Hg through the foodweb to the California sea lion.
Assuntos
Mercúrio , Leões-Marinhos , Oligoelementos , Poluentes Químicos da Água , Animais , Bioacumulação , México , Brasil , Cadeia Alimentar , Metais/análise , Mercúrio/análise , Oligoelementos/análise , Peixes , Poluentes Químicos da Água/análise , Monitoramento AmbientalRESUMO
We sampled abiotic and food web components in an impacted estuarine system to assess the transfer and fate of rare earth elements (REE). REE (based on dry weight) were measured in sediments, suspended particulate matter (SPM), and organisms from different trophic levels. The highest ∑REE concentrations were measured in sediments (180 ± 4.24 mg kg-1) and SPM (163 ± 12.6 mg kg-1). Phytoplankton (45.7 ± 5.31 mg kg-1), periphyton (51.6 ± 1.81 mg kg-1), and zooplankton (68.5 ± 1.27 mg kg-1) are the major sources of exposure and transfer of REE to the food web. REE concentrations were several orders of magnitude lower in bivalves, crustaceans, and fish (6.01 ± 0.11, 1.22 ± 0.18, and 0.059 ± 0.003 mg kg-1, respectively) than in plankton. The ∑REE declined as a function of the trophic position, as determined by functional feeding groups and δ15N, indicating that REE were subject to trophic dilution. Our study suggests that the consumption of seafood is unlikely to be an important source of REE for humans. However, given the numerous sources of dietary introduction of REE, they should be monitored for a possible harmful cumulative effect. This study provides new key information on REE's baseline concentrations and trophic transfers and patterns.