Effect of environmental factors on hematology profile of Gambusia affinis caught at Brantas River watershed, Indonesia

Background: Contamination of freshwater ecosystems has become a major issue as it threatens public water sources as well as aquatic life. It is important to predict changes in organism health, given a known number of environmental factors and pollutant concentrations, in order to better manage contaminants through biomarker analysis. This study aims to examine the ecosystem health of the Brantas River based on its environmental condition and the hematology profile of Gambusia affinis fish present in the river. This species was chosen because of its wide distribution along the Brantas River, and because it is very tolerant, adaptable, highly abundant, and easy to catch. Methods: The study area included 10 sampling sites along the Brantas River watershed. In total, six water quality parameters were observed (temperature, pH, dissolved oxygen (DO), biological oxygen demand (BOD), ammonia concentration, and phenol concentration) and hematology measurements consisted of erythrocyte, leucocyte, and micronuclei analyses. Results: The results showed that the upstream area of Brantas River, located in Batu, was the least polluted region, while Mojokerto was the most polluted. The erythrocyte level of Gambusia affinis caught in most sampling sites was quite low. Furthermore, research revealed that the status of Gambusia affinis' hematological profile was significantly correlated (p<0.05) with water quality parameters, particularly DO, BOD, ammonia, and phenol. Conclusions: It can be concluded from these results that the hematological profile of the fish is poor due to high levels of organic waste and harmful substances.

Gonadal histology of adult western mosquitofish (Gambusia affinis) following early life exposure to 17α-ethynylestradiol, 17β- trenbolone, and/or atrazine

Confined animal feeding operations (CAFOs) are a source of endocrine disrupting compounds (EDCs) in the aquatic environment and introduced there through agricultural runoff and insufficient waste storage systems. This study used the three compounds 17α-ethynylestradiol (EE2), 17β- trenbolone (TB), and atrazine (Atr) alone and in a mixture representing a simulated CAFO runoff. Laboratory exposures were performed in order to assess if early life exposure during the period of sexual differentiation to CAFO runoff altered gonadal development in western mosquitofish (Gambusia affinis). Juveniles were exposed to low and high concentrations of EE2 (50 or 250 ng/L), TB (10 or 50 ng/L), Atr (150 or 1,500 ng/L), or simulated CAFO runoff (50 ng/L EE2, 10 ng/L TB, and 150 ng/L Atr or 250 ng/L EE2, 50 ng/L TB, and 1,500 Atr) for 30-days followed by a 46-day recovery period. Gonadal histology was measured in adult males and females to assess stages of sexual development (i.e., oogenesis or spermatogenesis) and gonadal histopathology. All of the ovaries analyzed were in the maturing or mature stages of oogenesis, and all of the testes examined were in the intermediate or advanced stages of spermatogenesis. Intersex was observed in one individual exposed to 1,500 ng/L Atr. Ovarian histopathology was normal in all females, however testicular histopathology showed a loss of cyst structure leading to unbound interstitial sperm cells and unsynchronized cyst development in all males except the control fish. This study provided some evidence that exposure to simulated CAFO runoff and its individual compounds impaired testicular development.