Effects of chemical contaminants on wildlife: identification of biomarkers in a sentinel species

POLETTA, GL, A. LARRIERA, P. SIROSKI, MD. MUDRY, E. KLEINSORGE

Wildlife: Destruction, Conservation and Biodiversity

Nova Science Publishers

Lugar: New York, USA; Año: 2009; p. 1 - 20

Current agriculture activities worldwide imply extended used of chemical complex mixtures. Roughly 85–90% of pesticides applied in agriculture  never reaches target organisms, but disperse through the air, soil and water. Therefore, wildlife living in habitats adjoining heavily treated croplands is likely to be exposed to complex pesticide mixtures over extended periods.  One of the main challenges of the Environmental Toxicology is to relate the presence of a chemical in the environment with a valid prediction of the resultant hazards for those organisms potentially receptors. Alterations  or malfunction of organism normal vital functions can be identified using  Biomarkers, considered as measurable biochemical, histological, physiological, and morphological changes in response to xenobiotic undesirable action. Environmental pollution may interfere with growth and development of organisms, but the induction of genetic damage due to long-term, low level chronic exposure to chemicals is perhaps the most relevant biological effect. It can cause a decrease in wildlife populations fitness by the effects of somatic and heritable mutations, that is, an increase in genomic instability. Therefore, the evaluation of the potential genotoxicity of a chemical product is essential for environmental hazard assessment and biodiversity conservation. Genotoxic biomarkers, specially non-destructive short term tests, provide a particularly promising alternative of increasing interest and relevance for measuring the potential effects in vertebrate species in both, laboratory and field studies. Moreover, if this assessment is done in species of particular ecological value, the information can be used to assess the impact of xenobiotics on both the species and the ecosystem. The identification of sentinel species as well as sensitive biomarkers of chronic genotoxicity represents an early warning system to detect adverse effects in natural environments.  Crocodilians are integral components of wetlands all around the world. Taking into account the agricultural frontiers expansion  during the last years, many crocodilian populations live nowadays in habitats under a high contaminant pressure. Due to their biological characteristics they  can be exposed to contaminants in all life stages. As a consequence, crocodilians world-wide  appear as excellent model species of environmental pesticide contamination.