Search

• High SCCP and MCCP concentrations were found in raw cow milk from industrial areas. • SCCP concentrations in raw milk and silage were higher than MCCP concentrations. • Animal feed might be an important source of dairy cow exposure to SCCPs and MCCPs. • Bioconcentration factors for SCCPs and MCCPs in cow milk were calculated. • The exposure of Chinese residents to SCCPs and MCCPs via cow milk is minimal. Chlorinated paraffins (CPs) are industrial chemicals that are produced in large quantities and used globally. Human exposure to CPs is primarily through dietary intake, especially from animal-derived food products. Even so, there is little information regarding CP concentrations in dairy products. In this study, raw samples of cow milk were collected from various regions in China within the Neimenggu (n = 10), Hebei (n = 9), Shandong (n = 10), Henan (n = 10) and Hubei (n = 9) provinces. The mean concentrations of short chain CPs (SCCPs) and medium chain CPs (MCCPs) in the milk samples from industrial areas (1670 and 190 ng/g lipid, respectively) were higher than those from non-industrial areas (490 and 72 ng/g lipid, respectively). In most samples, C 10 H 16 Cl 6 and C 14 H 23 Cl 7 were the primary SCCP and MCCP congener groups, respectively. The mean concentrations of SCCPs and MCCPs in dairy cow feed (silage) were determined to be 750 and 36 ng/g dry weight, respectively. The SCCP and MCCP congener group patterns in the milk were similar to those in the silage, indicating that animal feed intake might be an important pathway for the exposure of dairy cows to CPs. Thus, the ingestion of CPs by humans through dairy products should not be neglected and the contamination of animal feed by CPs should be considered. [ABSTRACT FROM AUTHOR]