Chemical control of unwanted target organisms is a common practice in agricultural, recreational, and suburban areas throughout the United States. However, what is often overlooked is how such chemical use (e.g. pesticides) may affect non-target organisms. Non-target organisms within freshwater ecosystems can be exposed to a variety of these chemicals at low doses. For example, the use of the herbicide Atrazine (ATZ), a common chemical pollutant found in freshwater, can result in endocrine disruption in non-target organisms. One such organism, crayfish, are often abundant throughout freshwater streams and are likely exposed to ATZ. Previous findings (Chandler et al. 2017) involving a range of concentrations from 0.5-50.0 µg/L revealed an increase in tissue degradation as ATZ concentration increased. In the most recent experiment, a sample of thirty-two juvenile male crayfish were collected from a central Virginia stream and exposed to low-dose ATZ concentrations (0.05, 0.5, and 5.0 µg/L) for five months. Carapace length (CL), total length (TL), and blotted wet mass (BWM) were collected at monthly intervals over the course of the study to assess the effect of ATZ on crayfish growth. In addition, this study examines the effects of ATZ on tissue development of juvenile male crayfish with histological techniques.
Results/Conclusions
Significant differences in the growth of juvenile crayfish among low dose treatments were not observed. H&E and DAPI staining techniques were used to identify signs of tissue degradation and potential abnormalities from ATZ. Based on previous findings at higher ATZ doses (5.0-50.0 µg/L), it is expected that tissue will reveal observable differences between control and experimental groups (e.g. tissue degradation) from low dose (0.05-5.0 µg/L) ATZ exposure. Findings may be used to further examine the potential disturbance of chemical pollutants on non-target organisms.