Nowadays, organisms are increasingly being used in biomonitoring to assess bioavailability and bioaccumulation of contaminants. This approach can use both native and transplanted organisms in order to accomplish this task. In Brazil, most of the studies related to bioaccumulation of contaminants in oysters deal with metals. The present work employs this kind of test in Brazilian coastal estuaries (Santos and Paranaguá) to evaluate total mercury and polycyclic aromatic hydrocarbon contamination in sediments and oysters (native and caged Crassostrea rhizophorae). The methodologies employed were based on known USEPA methods. Results have shown a significant contamination in Santos sediments and consequent bioavailability of organisms. Paranaguá sediments presented lower contamination in sediments, but native oysters were able to accumulate total Hg. The experiments done with caged oysters did not show significant bioaccumulation of Hg and PAHs in the Paranaguá site, but proved to be an excellent tool to assess bioavailability in the Santos estuary since they were able to bioaccumulate up to 1,600% of total PAH in the samples from the inner part of this estuary when compared to control organisms. Multivariate statistical analyses employed to these results have separated the sites evaluated and the most contaminated samples from the least contaminated. 1. Introduction Some organic and inorganic chemical contaminants have the capacity of persisting in the environment, bioaccumulate in tissues, and are toxic to organisms. The main classes of elements and compounds that belong to this category are some metals such as mercury, cadmium, and lead as well as those denominated POPs (persistent organic pollutants) such as pesticides, dioxins, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) [1, 2]. Once in the environment, the contaminants interact with sediments, water column, and organisms; such interactions are controlled by several physical and chemical processes, and the final result may be the chemical release, immobilization, or their transformation into more reactive forms or subproducts, which are more effectively available to organisms [3]. Bioavailability is also governed by kinetics and partitioning of the contaminant in the environment [4]. Bioaccumulation is the process by which a chemical is absorbed by an organism exposed to it. It is a net result of competing processes of absorption, ingestion, digestion, and excretion [5] and involves also the endogenous processes of biological depuration. Bioaccumulation studies can
References
[1]
M. K. Hill, Understanding Environmental Pollution, Cambridge University Press, 3rd edition, 2010.
[2]
United States Environmental Protection Agency, “Bioaccumulation testing and interpretation for the purpose of sediment quality assessment. Status and needs,” Office of Water (4305). Office of Solid Waste (5307W). EPA-823-R-00-001. p. 111, 2000.
[3]
National Research Council, Bioavailability of Contaminants in Soils and Sediments: Processes, Tools, and Applications, National Academies Press, 2003.
[4]
C. J. Leeuwen and T. G. Vermeire, Risk Assessment of Chemicals: An Introduction, Springer, Dordrecht, The Netherlands, 2nd edition, 2007.
[5]
J. M. Neff, Bioaccumulation in Marine Organisms. Effect of Contaminants From Oil Well Produced Water, Elsevier, Amsterdam, The Netherlands, 2002.
[6]
E. Cortazar, L. Bartolomé, S. Arrasate et al., “Distribution and bioaccumulation of PAHs in the UNESCO protected natural reserve of Urdaibai, Bay of Biscay,” Chemosphere, vol. 72, no. 10, pp. 1467–1474, 2008.
[7]
International Mussel Watch, Initial Implementation Phase. Draft Final Report, National Oceanic and Atmospheric Administration, 1993.
[8]
M. C. R. Amaral, M. F. Rebelo, J. P. M. Torres, and W. C. Pfeiffer, “Bioaccumulation and depuration of Zn and Cd in mangrove oysters (Crassostrea rhizophorae, Guilding, 1828) transplanted to and from a contaminated tropical coastal lagoon,” Marine Environmental Research, vol. 59, no. 4, pp. 277–285, 2005.
[9]
M. Costa, E. Paiva, and I. Moreira, “Total mercury in Perna perna mussels from Guanabara Bay—10 years later,” Science of the Total Environment, vol. 261, no. 1–3, pp. 69–73, 2000.
[10]
M. F. Rebelo, M. C. R. Amaral, and W. C. Pfeiffer, “High Zn and Cd accumulation in the oyster Crassostrea rhizophorae, and its relevance as a sentinel species,” Marine Pollution Bulletin, vol. 46, no. 10, pp. 1354–1358, 2003.
[11]
C. A. R. Silva, B. D. Smith, and P. S. Rainbow, “Comparative biomonitors of coastal trace metal contamination in tropical South America (N. Brazil),” Marine Environmental Research, vol. 61, no. 4, pp. 439–455, 2006.
[12]
D. M. S. Abessa, R. S. Carr, E. C. P. M. Sousa et al., “Integrative ecotoxicological assessment of a complex tropical estuarine system,” in Marine Pollution: New Research, Nova Science, New York, NY, USA, 2008.
[13]
R. B. Choueri, A. Cesar, D. M. S. Abessa et al., “Development of site-specific sediment quality guidelines for North and South Atlantic littoral zones: comparison against national and international sediment quality benchmarks,” Journal of Hazardous Materials, vol. 170, no. 1, pp. 320–331, 2009.
[14]
R. B. Choueri, A. Cesar, R. J. Torres et al., “Integrated sediment quality assessment in Paranaguá Estuarine System, Southern Brazil,” Ecotoxicology and Environmental Safety, vol. 72, no. 7, pp. 1824–1831, 2009.
[15]
R. J. Torres, D. M. S. Abessa, F. C. Santos et al., “Effects of dredging operations on sediment quality: contaminant mobilization in dredged sediments from the Port of Santos, SP, Brazil,” Journal of Soils and Sediments, vol. 9, no. 5, pp. 420–432, 2009.
[16]
M. L. Lamparelli, M. P. Costa, V. A. Prósperi et al., Sistema Estuarino de Santos e S？o Vicente, Relatório Técnico CETESB, S？o Paulo, Brazil, 2001.
[17]
D. M. S. Abessa, R. S. Carr, B. R. F. Rachid, E. C. P. M. Sousa, M. A. Hortelani, and J. E. Sarkis, “Influence of a Brazilian sewage outfall on the toxicity and contamination of adjacent sediments,” Marine Pollution Bulletin, vol. 50, no. 8, pp. 875–885, 2005.
[18]
A. Cesar, C. D. S. Pereira, A. R. Santos et al., “Ecotoxicology assessment of sediments from Santos and Sao Vicente Estuarine,” System Brazilian Journal of Oceanography, vol. 54, no. 1, pp. 55–63, 2006.
[19]
United States Environmental Protection Agency, “A compendium of chemical, physical and biological methods for assessing and monitoring the remediation of contaminated sediment sites,” No. 68-W-99-033, p. 291, 2003.
[20]
United States Environmental Protection Agency, “Procedures for the derivation of equilibrium partitioning sediment benchmarks (ESBs) for the protection of benthic organisms: PAH Mixtures,” EPA-822-R-02-013, p. 175, 2003.
[21]
United States Environmental Protection Agency, Test Methods For Evaluating Solid Waste (SW-846), US Environmental Protection Agency, Office of Solid Waste, Economic, Methods, and Risk Analysis Division, 1996.
[22]
United States Army Corps of Engineers, “Use of sediment quality guidelines (SQGs) in dredged material management,” Dredging Research Technical Note EEDP-04-29, p. 14, 1998.
[23]
S. L. Simpson, G. E. Batley, A. A. Chariton et al., Handbook for Sediment Quality Assessment, CSIRO Publishing, Bangor, Australia, 2006.
[24]
R. J. Wenning, G. E. Batley, C. G. Ingersoll, and D. W. Moore, Use of Sediment Quality Guidelines and Related Tools for the Assessment of Contaminated Sediments, Society of Environmental Toxicology and Chemistry, 2005.
[25]
P. M. Medeiros and M. Caruso Bícego, “Investigation of natural and anthropogenic hydrocarbon inputs in sediments using geochemical markers. I. Santos, SP—Brazil,” Marine Pollution Bulletin, vol. 49, no. 9-10, pp. 761–769, 2004.
[26]
C. C. Martins, M. C. Bicego, and R. C. Montone, “Hidrocarbonetos marcadores geoquímicos em testemunhos de sedimentos do sistema estuarino de Santos e S？o Vicente, SP,” in Proceedings of the 28a Reuni？o Anual da Sociedade Brasileira de Química, Po？os de Caldas, Brazil, 2005.
[27]
A. A. Mozeto, R. J. Torres, F. C. Santos, M. DelGrande, D. M. S. Abessa, and M. R. L. Nascimento, “Effects of dredging activities on contaminated sediment quality: contaminant mobilization in dredging sediments of the Port of Santos, SP, Brazil,” in Proceedings of the 17th SETAC Europe Annual Meeting, p. 72, Porto, Portugal, May 2007.
[28]
N. M. Lawson and R. P. Mason, “Accumulation of mercury in estuarine food chains,” Biogeochemistry, vol. 40, no. 2-3, pp. 235–247, 1998.
[29]
N. M. van Straalen, “Chapter 18 Contaminant concentrations in organisms as indicators of bioavailability: a review of kinetic theory and the use of target species in biomonitoring,” Developments in Soil Science, vol. 32, pp. 449–477, 2008.
