Monitoring And Analysis Of Short-and Medium-Chain Chlorinated Paraffins In Ambient Air And Human Blood

Chlorinated paraffins(CPs)are a group of chlorinated derivatives of n-alkanes that are widely used as flame retardants and plasticisers in industrial products.Short Chain Chlorinated Paraffins(SCCPs)were officially listed in Annex A of the Stockholm Convention on Persistent Organic Pollutants(POPs)in May 2017 and Medium Chain Chlorinated Paraffins(MCCPs)were further proposed for listing in January 2022.The current studies on CPs are mostly focused on their environmental levels,but there is a lack of assessment of the sources of CPs production,human living environment and human exposure.In this paper,we conducted a study on the contamination characteristics of SCCPs and MCCPs in CPs production sources,monitored SCCPs and MCCPs in different indoor environments of human activities,and assessed the exposure levels of SCCPs and MCCPs in the blood of pregnant women.Firstly,the occupational exposure levels of workers in a production plant in China were assessed by monitoring the concentrations of SCCPs and MCCPs in the indoor and outdoor ambient air of the production workshop of a CPs production plant.The results revealed that the concentrations of SCCPs were significantly higher in the workshop than in the outdoor environment.Both SCCPs and MCCPs in the gas-phase samples accounted for>80%of their total concentration in the ambient air.The occupational exposure risk assessment indicated that the occupational exposure of production plant workers to MCCPs through breathing air was higher than that of SCCPs,with a maximum exposure of 137.2 ng/kg/day for workers to MCCPs,and no significant adverse reactions to SCCPs and MCCPs in the ambient air of this CPs production plant were observed for occupational practitioners.Secondly,SCCPs and MCCPs in the gas and particle phases in different types of indoor microenvironments(student dormitories,offices,laboratories and underground stations)were collected and analysed,and then the exposure levels of SCCPs and MCCPs of the population in the above different indoor microenvironments were evaluated.The results showed that the highest mean concentrations of SCCPs(134.68 ng/m~3)were found in the air of the student dormitories and the highest mean concentrations of MCCPs(218.03 ng/m~3)were found in the metro stations.The total daily exposure dose(DEDt)and hazard quotient(HQ)calculated from the human exposure risk assessment were lower than the reference doses(Rf Ds)specified by the International Programme on Chemical Safety(IPCS),indicating that there was no potential health risk to adults from SCCPs and MCCPs in the monitored indoor ambient air.Finally,the concentration levels of SCCPs and MCCPs in different fractions of the blood of gestational diabetics and non-diabetics were measured,and correlated with different ages,different body mass indexes(BMI)and gestational diabetes of pregnant women.Overall,the concentrations of SCCPs and MCCPs in red blood cells>plasma>white blood cells and platelets.There was a correlation between the levels of total concentrations of SCCPs and MCCPs in different fractions of blood and the age and BMI of pregnant women.There was no significant difference in the mean concentration levels of SCCPs between gestational diabetics and non-diabetics,while there was some difference in the concentration of MCCPs.