Health Impact Assessment of Sulfolane on Embryonic Development of Zebrafish (Danio rerio)

Sulfolane is a widely used polar, aprotic solvent that has been detected by chemical analysis in groundwater and creeks around the world including Alberta, Canada (800 mu g/mL), Louisiana, USA (2900 mu g/mL) and Brisbane, Australia (4344 mu g/mL). Previous research provided information on adverse effects of sulfolane on mammals, but relatively little information is available on aquatic organisms. This study tested the effects of sulfolane (0-5000 mu g/mL) on early development of zebrafish larvae, using various morphometric (survival, hatching, yolk sac and pericardial oedema, haemorrhaging, spinal malformations, swim bladder inflation), growth (larval length, eye volume, yolk sac utilisation), behavioural (touch response, locomotor activity and transcript abundance parameters (ahr1a, cyp1a, thraa, dio1, dio2, dio3, 11 beta hsd2, gr, aqp3a, cyp19a1b, ddc, gria2b and hsp70) for 120 h. Embryos were chronically exposed to sulfolane throughout the experimental period. For locomotor activity, however, we also investigated acute response to 2-h sulfolane treatment. Sulfolane sensitivity causing significant impairment in the observed parameters were different depending on parameters measured, including survival (concentrations greater than 800 mu g/mL), morphometric and growth (800-1000 mu g/mL), behaviour (500-800 mu g/mL) and transcript abundance (10 mu g/mL). The overall results provide novel information on the adverse health impacts of sulfolane on an aquatic vertebrate species, and an insight into developmental impairments following exposure to environmental levels of sulfolane in fish embryos.