Conclusions: Biomarkers in Environmental Risk Assessment - Ecological Biomarkers: Indicators of Ecotoxicological Effects - page 423

consequences of endocrine disruption effects associated with the presence of EE2 have
been established in the field (Kidd et al. 2007) or forecast through modeling of the effects
of five chemicals (17β-trenbolone, 17α-trenbolone, prochloraz, fenarimol, and fadrozole)
that inhibit VTG production through different mechanisms (Miller et al. 2007; see Figure
16.2). A recent paper by Sanchez et al. (2011) supports the hypothesis that pharmaceutical
compounds discharged into streams are involved in endocrine disruption effects and fish
population disturbances, and threaten the disappearance of resident fish species. Recently,
Lewis and Ford (2012 have reviewed the current knowledge regarding pollutants impact-
ing male infertility across several aquatic invertebrate phyla. If the number of studies in
invertebrates remains low, biomarkers developed for human infertility clinics (sperm
tracking, measurements of DNA strand breaks and sperm viability) provide useful tools
for the study of infertility in male aquatic invertebrates. So these authors conclude that it
represents a good opportunity for a better understanding of reproductive abnormalities,
providing a sound basis to link sperm toxicity and male infertility effects to higher level
impacts on the reproductive biology and dynamics of populations.
All the evidence for an endocrine effect in amphibians is reliant on the correct inter-
pretation of biomarker data. In Chapter 9, it is concluded that there is an effect of atrazine

1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
0.00

(a)

0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00

Relative vitogenin concentration

1

(b)

0

0.8

0.6

25

0.4

0.2

50

96 75

0 0

5 10 20 25

15

Time (year)

FIGURE 16.2
Linking biochemical responses to population-level effects in the freshwater fish Pimephales promelas . (a) Rela-
tionship between vitellogenin (VTG) concentration in plasma and fecundity. (b) Effect of reduction in VTG
concentration in plasma and population size—0: no VTG reduction; 25, 50, 75, 96: VTG reduced by 25%, 50%,
75%, or nearly 96%.