Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in water and suspended particulate matter from the Xijiang River, China

Concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in water and suspended particulate matter (SPM) collected from the Xijiang River, China, were measured by the quarter from September 2005 to June 2006. Total PCDD/F concentration ranged from 2.659 to 4.596 pg/L for water and from 562.4 to 3259.5 pg/g for SPM. Concentrations were high in summer and low in winter. I-TEQ values in water and SPM were low, ranging from 0.012 to 0.075 pg/L, with a mean value of 0.039 pg/L. Calculated annual loadings of total PCDD/Fs and I-TEQ were 8.55 kg and 0.026 kg, respectively. Composition and homologue distribution of PCDD/Fs were varied because of large seasonal differences in discharge from the Xijiang River into the South China Sea. Comparison of the PCDD/Fs homologue and congener profiles of atmospheric deposition, soil, and water revealed that soil was the dominant source of PCDD/Fs in the Xijiang River. Industrial effluents were also possible sources of PCDD/Fs. A good correlation between log Koc and log Kow was observed for 2,3,7,8-substituted PCDDs and PCDFs and correlation coefficients were 0.71 and 0.84, indicating organic matter in SPM played a dominant role in PCDD/Fs partition between SPM and water.