Reproductive toxicity exposure biomarkers

Decreased sperm count has been observed following exposure to mirex or chlordecone in humans and/or experimental animals. Clinically, the most straightforward biomarker would be examination of sperm in the ejaculate. However, testicular biopsies may also be helpful. Both procedures have been used to assess the male reproductive toxicity of chlordecone in exposed persons (Taylor et al. 

In the past few years the use of rotifers in ecotoxicological studies has substantially increased. The main endpoints used are mortality, reproduction, behavior, cellular biomarkers, mesocosms, and species diversity in natural populations [126]. Several workers have used Brachionus calyciflorus for various types of toxicity assessments. Thus, comprehensive evaluation of approximately 400 environmental samples for the toxicity assessment of solid waste elutriates, monitoring wells, effluents, sediment pore water, and sewage sludge was carried out by Persoone and Janssen [127]. The mortality of rotifers hatched from cysts is evaluated after 24 hours exposure. This microbiotest has been commercialized in a Rotoxkit F [128,129]. 

Substances that are carcinogenic, mutagenic, or reproductively toxic (i.e., CMRs), for example, some endocrine disrupters, may pose special problems for derivation of aquatic EQSs (e.g., lack of internationally agreed tests in some cases difficulties with prediction of safe concentrations), but use of special tests for these properties is only justified for a small subset of chemicals that meet clear criteria. Furthermore, EQSs for these substances should not be derived directly from in vitro data or from biomarkers of exposure but from in vivo tests alone. 

Data for PCP and terrestrial wildlife are incomplete and — in view of the large interspecies variations in sensitivity — need to be collected. Research is needed on reproductive effects in animals following inhalation exposure to PCP additional acute and intermediate toxicity testing chronic duration exposure studies on cancer induction, genotoxicity, and immunotoxicity and the development of alternate biomarkers of PCP exposure and antidotes (WHO 1987 USPHS 1994). Until the results of these studies become available, it seems reasonable to apply to wildlife the same levels recommended for human health protection. 

Reproductive system Environmental arsenic exposure can impair male fertility. A case-control study in China concluded that elevated inorganic arsenate (Asi(V)) exposure is associated with arsenic-induced male infertility. The mechanism of toxicity by arsenic species may involve oxidative stress and sexual hormone disruption measured by biomarkers including acylcamitines, aspartic acid and hydroxyestrone, which were negatively associated with infertility, and uridine and methylxanthine, which were positively associated [44 ]. Arsenic exposme is also correlated to a decrease in human semen quality as reported in a reproductive-age Chinese cohort. The study demonstrated significant association of dimethyl arsenic species (DMA) concentration with low sperm concentrations [45 -]. 

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