| dc.description.abstract | Inappropriate management of pesticides usage may result to environmental pollution with far reaching effects on the reproduction and survival potential of aquatic animals, particularly fish. For example, the use of pesticides on agricultural land or their presence in leachates can result in the contamination of adjacent surface water and thus pose a potential risk to a range of aquatic organisms (Zhang et al., 2013). For example, some organophosphate pesticides such as the Monocrotophos (MCP, CAS number 6923-22-4) are no longer used in developed countries, but it is still extensively used in agriculture in some developing countries (Zhang et al., 2013). For example, concentrations of MCP detected in source water in China and in rainwater in India were 0.165 and 4 lg/L, respectively (Kumari et al., 2007; Zhang et al., 2013).
Recently, we observed that the Organophosphates - (tris(chloropropyl) phosphate -TCPP, triethyl phosphates-TEP and tributyl phosphates (iso- and n-isomer; TiBP and TnBP) have been shown to reach the environment through landfill leachates and waste water treatment plant (WWTP) effluents in Norway and represent significant source for one of the TBP isomers, TnBP (6000 ng/L) (Eggen et al. in prep). Another isomer, TiBP, showed similar concentration level in leachates and WWTP influent sample (7100-9700 ng/L) (Eggen et al. in prep). However, it should be noted that the tris(butyl)phosphate isomers were determined at higher concentration than the TCPP isomers in the water phase of the landfill leachates, compared with particle phase. Non-chlorinated organophosphates are reported to be more efficiently eliminated in WWTPs than the chlorinated isomers (Meyer, 2004). However, extreme and high daily variation of the organophosphate contents was observed in WWTP influents and this may briefly influence the ratio between non-chlorinated and chlorinated organophosphates (Meyer, 2004). In our recent study, the adsorbed amounts of organophosphates on particles were not measurable, while previous studies reported high concentrations of 5100 ng TBP/g d.w., and 699-20000 ng TCPP/g d.w. in sludge, indicating sorption and accumulation potential despite low Kow values (Marklund, 2005; Thomas, 2007). Organophosphate pesticides have been shown to be highly toxic to birds, honeybees and fish. For example, they has been shown to cause endocrine disruption of the hypothalamic pituitary gonadal axis (HPG axis) in male goldfish (Carassius auratus) and phenotypic feminization in male guppies (Poecilia reticulata) and in zebrafish (Danio rerio) (Tian et al., 2012; Zhang et al., 2013)(Xu et al., 2012). | en |
