Accumulation,Transformation And Developmental Toxicity Of Typical Organophosphate Flame Retardants In Organisms

Organophosphorus flame retardants?OPFRs?are a class of synthetic chemicals.Because of their distinguished flame retardant properties,OPFRs are widely used in chemical,textile,electronics and building materials industries.However,OPFRs are mainly added to various materials by physical doping rather than chemical bonding,thus they could be easily released into the environment through abrasion,volatilization,etc.At present,OPFRs have been detected in a variety of environmental media and biological samples,which has been considered as a new class of organic pollutants.It has been attracted great interest to investigate the bioconcentration,biotransformation and toxicology of such pollutants in environmental science.At present,the in vivo extraction methods and enrichment studies for OPFRs are mainly focus on the aquatic organisms,with the rapid increased concentration of OPFRs in the environment,and their toxic effects and mechanisms need to be clarified.Therefore,it is urgent and essential to clarify the tissue distribution and adverse effects of OPFRs in terrestrial animals.Firstly,the procedures of extraction and purification,as well as chromatographic and mass spectrometric parameters were optimized.An effective method for determination of typical OPFRs in organism by GC-MS/MS with ultrasonic-assisted solvent extraction and non-primary secondary amine?PSA?purification was developed.Under the optimized conditions,our results showed that recoveries of Tn BP-d₂₇ and TPh P-d₁₅ were 104.86%and102.12%,respectively,showing a suitable extraction method.The tissue samples were obtained from mice after tail intravenous injection with different time points.The calibration curves showed good linearity in 1-1000?g·L^-1 with correlation coefficients of r²>0.99,the relative standard deviation?RSDs?is 9.58%-18.21%.The limits of detection were0.02-1.08?g·L^-1 and the limits of quantification were 0.06-3.61?g·L^-1.Spleen and kidney were the most obvious tissues for Tn BP-d₂₇ bioaccumulation with the concentration of8.55±1.00 ng·g^-1 in spleen after the 36 h exposure,and 20.34±6.60 ng·g^-1 in kidney after the24 h exposure.Based on above analysis,it is effective and accurate to apply this method to quantify the OPFRs in terrestrial animals tissues.Secondly,to address this knowledge gap,C57BJ/6 mice were exposed to 7PM_2.5-associated OPFRs via the trachea to study their bioaccumulation and tissue distribution.Using C57BJ/6 mice as model organisms,we explored the accumulation and distribution of 7 OPFRs in various tissues of mice based on atmospheric concentration and found that the total concentration and exposure concentration of the 6 detected OPFRs in tissues were found.After 72 days'exposure,concentrations in the mice increased significantly and dose-dependently.concentrations in tissues from mice in the medium dosage group decreased in the order intestine>heart>stomach>kidney>spleen>brain>liver>lung>muscle.Of the OPFRs detected in mice from all three exposure groups,chlorinated alkyl OPFRs?TCPP,TDCPP,and TCEP?were the most heavily accumulated,with average concentrations of 61.617±6.314,49.650±3.414 and 43.141±3.745 ng·g^-1 ww in the medium dosage group.We found a significant positive correlation between the bio-absorption ratio and octanol-air partition coefficient(K_OA)in mice tissues for low log K_OW OPFR congeners?R²=0.971,P=0.016<0.05?rather than exposure concentrations or octanol-water partition coefficient?Kow?.The health risks of OPFR congeners in different tissues were calculated using a commercial online platform?ACD Labs server?based on their physiochemical properties.In the medium dosage group,predicted tissue-specific health risks increased linearly and specifically with increasing tissue-specific accumulation concentrations.Three urinary biomarkers?di-p-cresyl phosphate:DCr P,diphenyl phosphate:DPh P,Dibutyl phosphate:Dn BP?were detected in mice from the medium dosage group.These results provide important insights into the bioaccumulation potential of OPFRs in terrestrial animals and emphasize the health risk of chlorinated alkyl OPFRs.Finally,the toxicity of OPFRs was studied,focusing on the developmental toxicity of TPh P.Using mouse embryonic stem cells as an in vitro experimental model to detect the proliferation and developmental toxicity of TPh P on mouse embryonic stem cells?m ESCs?,the results showed that TPh P exposure would affect the proliferation of m ESCs and thus affect the growth of m ESCs.Subsequently,in zebrafish embryos,exposure to TPh P resulted in broad,concentration?dependent developmental defects and coupled with heart malformation and reduced heart rate.In conclusion,the two models demonstrate that acute exposure to TPh P affects early embryonic development and disturbs the cardiomyogenic differentiation.The development of this paper not only provides a basis for the bioconcentration and transformation characteristics of emerging organic pollutants and environmental health research,but also provides an important scientific basis for China's chemical management and control.