Atrazine is a herbicide used throughout the midwestern United States to prevent broadleaf weeds in crops. The U.S. Environmental Protection Agency (EPA) has set the maximum contaminant level at 3 ppb (μg/L) in drinking water. Atrazine is an endocrine disrupter interfering with the function of hormones and disrupting normal physiology and homeostasis throughout development and the life course of an organism. The zebrafish model was used to test the hypothesis that an embryonic parental atrazine exposure will cause modifications in morphology in developing offspring. AB adult zebrafish were bred. Embryos were collected and exposed to atrazine concentrations of 0, 0.3, 3, or 30 ppb from 1 to 72 hours post fertilization (hpf; the end of embryogenesis). Atrazine exposure ceased at 72 hpf and larvae were grown into adulthood in aquaria water (F0). Atrazine F0 adult zebrafish were then bred within their treatment group. Their embryos were collected and placed in petri dishes in aquaria water until 120 hpf. At 120 hpf, larvae were collected for morphological analysis including general morphology measurements and co-staining with alcian blue and alizarin red for cartilage and skeletal assessments. Head length and ratio of head length to total length was significantly increased in the F1 0.3 and 30 ppb atrazine groups (p < 0.05). The posteriorly positioned notochord indicated delayed ossification and skeletal growth. These findings signify that a single embryonic parental exposure leads to changes in craniofacial development in their offspring.
"Parentally Exposed Zebrafish Larvae Have Altered Craniofacial Measurements: Multigeneration Developmental Atrazine Toxicity,"
The Journal of Purdue Undergraduate Research:
Vol. 13, Article 3.