Interactions between effects of environmental chemicals and natural stressors: A review.

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Interactions between effects of environmental

chemicals and natural stressors: A review.

Holmstrup M, Bindesbøl AM, Oostingh GJ, Duschl A,

Scheil V, Köhler HR, Loureiro S, Soares AM, Ferreira AL, Kienle C, Gerhardt A,

Laskowski R, Kramarz PE, Bayley M, Svendsen C, Spurgeon DJ.

Sci Total

Environ. 2009 Nov 16. [Epub ahead of print]

National Environmental Research Institute, Aarhus

University, Department of Terrestrial Ecology, Vejlsøvej 25, DK-8600 Silkeborg,

Denmark.

Ecotoxicological effect studies often expose test

organisms under optimal environmental conditions. However, organisms in their

natural settings rarely experience optimal conditions. On the contrary, during

most of their lifetime they are forced to cope with sub-optimal conditions and

occasionally with severe environmental stress. Interactions between the effects

of a natural stressor and a toxicant can sometimes result in greater effects

than expected from either of the stress types alone. The aim of the present

review is to provide a synthesis of existing knowledge on the interactions

between effects of " natural " and chemical (anthropogenic) stressors. More than

150 studies were evaluated covering stressors including heat, cold, desiccation,

oxygen depletion, pathogens and immunomodulatory factors combined with a variety

of environmental pollutants. This evaluation revealed that synergistic

interactions between the effects of various natural stressors and toxicants are

not uncommon phenomena. Thus, synergistic interactions were reported in more

than 50% of the available studies on these interactions. Antagonistic

interactions were also detected, but in fewer cases. Interestingly, about 70% of

the tested chemicals were found to compromise the immune system of humans as

judged from studies on human cell lines. The challenge for future studies will

therefore be to include aspects of combined stressors in effect and risk

assessment of chemicals in the environment.

PMID: 19922980 [PubMed - as supplied by

publisher]