Keywords: biomarkers, cholinesterase, POPs, metallothionein, heavy metals, neutral red, Perkinsus marinus, Terminos Lagoon, biological effects, environmental pollution, toxic pollutants, Mexico, organochlorine compounds, hydrocarbons, histopathology, oysters, principal components analysis, PCA, pesticides
Biological effects of environmental pollutants in American Oyster, Crassostrea virginica: a field study in Laguna de Terminos, Mexico
The response of Crassostrea virginica to a complex mixture of toxic contaminants was studied at four sites in Laguna de Terminos, Mexico. Contaminants assessed were heavy metals, organochlorine compounds, and hydrocarbons. Biomarkers (cholinesterase activity, neutral red retention, and metallothionein), histopathology and prevalence of Perkinsus marinus were used to evaluate the effects of contaminants. The resultant contaminant body burden was moderately as high as a whole, and biomarker levels were also moderate. Oedema in the gills and systemic haemocytosis were the only histopathological lesions observed. P. marinus was never evidenced in the oyster tissues examined. Statistical results from principal components analysis show that metallothioneins are positively correlated with copper and chromium, neutral red and oedema with chlordanes, pentachloroanisol, drins, polychlorobiphenyls and total pesticides, total hydrocarbons and polycyclic aromatic hydrocarbons, whereas cholinesterase activity is negatively correlated to Cu and Cr. The biomarkers used were sensitive indicators responding to moderate levels of pollutants.