Examples of Monitoring Studies on Developmental and Reproductive Disturbances in Wildlife with Suspected Chemical Etiology

Environmental monitoring programs on endocrine active compounds (EACs) have been used to document the level of exposure and to assess the possible association to the occurrence of developmental and reproductive disorders in wildlife. The establishment of causal links between exposure and effect data, however, was found to be difficult due to, for example, the presence of confounding factors or limited understanding of EAC mechanisms and interactions, but also because of conceptual and methodological limitations of current monitoring strategies. In order to provide plausibility of an EAC etiology for a developmental or reproductive alteration in a wildlife population, integrated monitoring programs are needed that will use a combination of complementary approaches: methods for a targeted search for suspected EACs in an environmental mixture, analysis of internal EAC doses instead of external EAC concentrations, utilization of mechanism-based endpoints in bioanalytical and effect monitoring, investigation of the basic biology and physiology of wildlife sentinel species, laboratory replication of field effects, as well as consideration of epidemiological and weight-of-evidence criteria in the design and data evaluation of monitoring programs.