Study On Water Quality Criteria And Risk Assessment Of Organophosphate Esters

Organophosphate esters（OPEs）flame retardants are substitutes for brominated flame retardant.They have been detected frequently in various environment mediums and organisms.OPEs have been widely concerned due to their potential reproductive toxicity,carcinogenicity and endocrine disturbance effect.As typical OPEs,triphenyl phosphate（TPh P）,tris（1,3-dichloro-2 propyl）phosphate（TDCIPP）,tris（2-chloroisopropyl）phosphate（TCIPP）and tris（2-chloroethyl）phosphate（TCEP）have high detection rates and concentrations in the environment.Moreover,they have potential toxicity to aquatic organisms and human health.Therefore,water quality criteria and risk assessment were conducted for these 4 OPEs in this study.Firstly,Chinese resident aquatic organisms from“3 phyla and 8 families”were screened for acute and chronic toxicity tests of TPh P and TDCIPP.Species sensitivity Rank（SSR）,Log-logistic and Log-normal SSD were used for deriving their aquatic life criteria（ALC）respectively,and ecological risks in surface water and sewage treatment plant effluents in China and abroad were assessed.Secondly,human health water quality criteria and health risk assessment of TCIPP and TCEP were studied with the exposure parameters of the population in the Taihu Lake Basin.The main conclusions are as follows:（1）Based on SSR,the Criteria maximum concentration（CMC）and Criteria continuous concentration（CCC）of TPh P are deduced to be 411.3μg/L and 47.90μg/L,respectively.The acute PNEC values derived based on the Log-logistic and Log-normal SSD methods are 376.7μg/L and 372.6μg/L;the CMC and CCC of TDCIPP derived according to SSR are 764.1μg/L and 143.4μg/L,respectively.The acute PNEC values derived from Log-logistic and Log-normal SSD methods are 666.0μg/L and 735.1μg/L.The results showed that the difference of aquatic life criteria obtained by the above mainstream derivation methods was not significant.The ecological risk assessment results showed the ecological risks of TPh P and TDCIPP in China and abroad surface water and sewage treatment plant effluents were at acceptable levels,but for sewage treatment plants,the ecological risks of TDCIPP should be paid especial attention.（2）Species sensitivity analysis based on toxicity data of native and non-native organisms of TPHP,the results showed that the sensitivity of non-native organisms was higher than native organisms.Secondly,based on the minimum toxicity data requirements（MTDR）of“3 phyla and 8 families”suggested by the US EPA,the MTDRs of“3 phyla and 6 families”were analyzed.The results showed that the MTDRs of“3 phyla and 6 families”criteria values of deleted two aquatic organisms were similar with the“3 phyla and 8 families”MTDRs criteria values.The two types of calculated values for TPHP are close,with a difference of 6.993%.However,the calculated values for TDCIPP are slightly difference of 82.01%,but there are no difference of order of magtitude.The results showed that“3 phyla and 6 families”is basically feasible when there are insufficient toxicity data of native species in China,but there are some uncertainties.（3）Based on the population exposure parameters and bioaccumulation factor in the Taihu Lake Basin,the non-carcinogenic human health water quality criteria values of TCIPP and TCEP in the Taihu Lake basin are derived as 55.62μg/L and35.43μg/L respectively.The carcinogenic human health water quality criteria value of TCEP is 1.266μg/L.The results showed that the non-carcinogenic health risks of TCIPP and TCEP in the waters of Taihu Lake were at acceptable levels.However,the carcinogenic risk of TCEP in some sites reach 1.144×10^-6,indicating that TCEP may pose potential carcinogenic(10^-6risk level).