Interactions between effects of environmental chemicals and natural stressors: a review.
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.
Holmstrup
Martin
M
National Environmental Research Institute, Aarhus University, Department of Terrestrial Ecology, Vejlsøvej 25, DK-8600 Silkeborg, Denmark. martin.holmstrup@dmu.dk
Bindesbøl
Anne-Mette
AM
Oostingh
Gertie Janneke
GJ
Duschl
Albert
A
Scheil
Volker
V
Köhler
Heinz-R
HR
Loureiro
Susana
S
Soares
Amadeu M V M
AM
Ferreira
Abel L G
AL
Kienle
Cornelia
C
Gerhardt
Almut
A
Laskowski
Ryszard
R
Kramarz
Paulina E
PE
Bayley
Mark
M
Svendsen
Claus
C
Spurgeon
David J
DJ
D000818:Animals; D003080:Cold Temperature; D003890:Desiccation; D054750:Ecotoxicology; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000737:chemistry / Q000633:toxicity*; D010273:Parasitic Diseases, Animal / Q000503:physiopathology; D013312:Stress, Physiological
D004785:Environmental Pollutants