Seasonal variations and inhalation risk assessment of short-chain chlorinated paraffins in PM_2.5 of Jinan, China

Short-chain chlorinated paraffins (SCCPs) were added to the Stockholm Convention on Persistent Organic Pollutants (POPs) at the eighth meeting of the conference of the parties in 2017. As a consequence, increasing environmental attention and international regulation on SCCPs is expected in the future. Inhalation uptake of particulate matter (PM) was an important exposure pathway for POPs into the human body. In the present study, a total of eighty PM_2.5 samples were collected in the four seasons of the year at an urban site (Shandong University, Jinan) in Shandong province to investigate the seasonal changes of SCCPs and their inhalation exposure risks to human health. The concentrations of SCCPs ranged from 9.80 to 105 ng m⁻³, with the mean value of 38.7 ng m⁻³. The highest concentrations of SCCPs were detected in winter, while the lowest concentrations were in summer. SCCPs concentrations were positively correlated with the mass concentrations of PM_2.5 (r = 0.629, p < 0.01), and negatively correlated with the ambient temperature (r = −0.447, p < 0.01). The SCCPs congeners with 10 carbon atoms (C₁₀ congeners) and 7 chlorine numbers (Cl₇ congeners) were the predominant congeners, which contributed 35% and 37% of the total SCCPs contamination, respectively. The average inhalation exposure was estimated to be 1.75 × 10⁻⁴ mg kg⁻¹ day⁻¹ for adults, which is much lower than the “no observed adverse effect level” (NOAEL) of 100 mg kg⁻¹ day⁻¹ given by European risk assessment for SCCPs. The exposure of SCCPs via inhalation poses no significant risk for human health in Jinan and the results of present study could provide valuable information on the inhalation exposure risk assessments of SCCPs in the industrial cities.