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Water samples collected from upstream tributaries of the Pearl River Delta (PRD) and from locations within the PRD (South China) were analyzed for 27 polycyclic aromatic hydrocarbons (PAHs). Average concentrations (aqueous plus particulate) of total 27 PAHs (Σ27PAH), 16 priority PAHs designated by the United States Environmental Protection Agency (USEPA) except naphthalene (Σ15PAH), and the seven carcinogenic PAHs (Σ7PAH) classified by the USEPA were 260 ± 410, 130 ± 310, and 15 ± 12 ng/L, respectively. Riverine PAHs were predominantly generated from coal and vegetation combustion, coke production, vehicle exhausts, and petroleum residues, accounting for 28%, 25%, 22% and 21%, respectively, on average. Upstream riverine fluxes of Σ27PAH and Σ15PAH amounted to 38.9 and 12.9 tons/year, respectively. The net contributions of Σ27PAH and Σ15PAH from sources within the PRD were estimated at 21.4 and 21.0 tons/year, respectively. [Copyright &y& Elsevier]

Abstract: A large-scale sampling program was conducted to simultaneously collect water samples at the eight major riverine runoff outlets of the Pearl River Delta (PRD), South China to assess the importance of riverine runoff in transporting anthropogenic pollutants from terrestrial sources to the coastal ocean. The concentrations of ∑21OCPs (sum of 21 OCP components) and ∑20PCBs (sum of 20 PCB congeners) were 2.57–41.2 and 0.12–1.47ng/L, respectively. Compositional distributions of DDTs suggested the possibility of new input sources in the study area, but contributions from dicofol seemed considerably low. The annual inputs of ∑21OCPs and ∑20PCBs were 3090 and 215kg, with those of total HCHs and DDTs being 1110 and 1020kg, respectively. A mass balance consideration indicated that riverine runoff is the major mode carrying OCPs from the PRD to the coastal ocean, and the majority of OCPs is further dissipated to open seas. [Copyright &y& Elsevier]

The occurrence and phase distribution of polycyclic aromatic hydrocarbons (PAHs) in waters at the eight riverine outlets of the Pearl River Delta (China) were examined based on a monthly sampling program from March 2005 to February 2006. The total concentrations of PAHs in the aqueous phase and suspended particulate matter (SPM) combined ranged from 55.5 to 522ng/L, at the mid level of the global values in rivers and estuaries. No clear temporal and spatial trends of PAH concentrations were found. However, the concentrations of PAHs associated with SPM coincided with the monthly precipitation of Guangzhou, indicating the importance of atmospheric deposition. The PAHs found in the region were likely derived from a combined pyrolytic and petrogenic origin, as suggested by the molecular indices of PAHs. Normalized partition coefficient (K oc) between water and SPM was correlated with octanol–water partition coefficient (K ow) to understand the environmental behavior of PAHs. [Copyright &y& Elsevier]