First insight into the levels and distribution of flame retardants in potable water in Pakistan: An underestimated problem with an associated health risk diagnosis.

To date, very little is known about the occurrence of flame retardants (FRs) in potable water and its associated health risk to the exposed human population. The current study was designed to investigate the differences in the contamination levels of selected FRs in the potable water of industrial, rural and background zones of Pakistan. In addition, the health risk assessment for the exposed human population was estimated. For this purpose, the concentrations of the selected FRs: polybrominated diphenylethers (PBDEs), dechlorane plus (DP), novel brominated flame retardants (NBFRs) and organophosphate flame retardants (OPFRs), were analyzed in a total of 39 samples of potable water from the above mentioned three zones. We found elevated concentrations of ∑OPFRs (BDL-71.05ng/L), ∑PBDEs (BDL-0.82pg/L), ∑NBFRs (BDL-1.39pg/L) and ∑DP (BDL-0.29pg/L) in the potable water samples from industrial zones, smaller concentrations in the samples from rural zones, and negligible concentrations in the samples from background zones. Among all the FRs analyzed, Tris-(2-chloroisopropyl)-phosphate (∑TCPP), anti-DP, BDE-47 and 1.2-bis(pentabromodiphenyl)ethane (DBDPE) were the dominant compounds in all three selected zones. Principal component analysis (PCA) revealed that most of the FRs are associated with the industrial zones. The estimated daily intake (EDI) for all selected FRs was found to be higher in children than adults. However, both children and adults were found to be at low risk (i.e., Hazard quotient (HQ)<1) of FRs exposure through potable water consumption. We predict that FRs might be leached out from wastewater bodies and subsequently mixed with nearby potable water facilities. FRs may also spill out from the aluminum or plastic pipes and tanks most commonly used for potable water storage in Pakistan. The present study suggests initiating measures to minimize human exposure to FRs in the future.