[Distribution Characteristics and Ecological Risk Assessment of Organochlorine Pesticides in Sediments of Zhanjiang Bay].

Sixteen surface sediment samples were collected from the estuary of the Suixi river to the mouth of Zhanjiang Bay and then analyzed for organochlorine pesticides (OCPs) by GC-MS to investigate their distribution and ecological risk. The results showed that the concentrations of OCPs in the sediments ranged from nd to 189.52 ng·g-1 (mean 32.17 ng·g-1), including HCHs (mean 5.81 ng·g-1) and DDTs (mean 26.90 ng·g-1). The distribution characteristics showed that the highest OCPs concentrations were found in the estuary and the main shipping lane areas, and the concentration in the nearshore area was higher than that offshore. Source analysis indicated that the HCHs mainly originated from agricultural applications, while no industrial input was observed. Some "hot-spots" areas occurred in harbors and shipping channels, likely as a result of the presence of paint flakes. Additionally, the concentrations of DDTs were found to be higher than the limits of Chinese Marine sediment quality criteria, and p,p'-DDT was the main type of DDT, presenting inevitable adverse biological effects and high ecological risk. Compared with other bays in China, the concentrations of OCPs in this study were in the upper-median pollution level, especially in harbors and boat maintenance facility areas. High OCPs inputs may occur, and thereby represent a certain ecological risk in Zhanjiang Bay.

Occurrence and carcinogenic potential of airborne polycyclic aromatic hydrocarbons in some large-scale enclosed/semi-enclosed vehicle parking areas.

Polycyclic aromatic hydrocarbons (PAHs) originating from vehicle exhaust have aroused much attention due to their potential healthy effect. In this study, air samples were collected from three representative parking lots in a metropolitan area, analyzed for PAHs and evaluated for inhalation risk. Atmospheric PAH levels of these parking areas ranged between 1,178-4,793 ng m(-3), one order of magnitude higher than general urban areas. Their benzo[a]pyrene equivalent (BaPeq) values varied in 11.0-98.0 ng m(-3), far exceeding the air quality standard of WHO (1.0 ng m(-3)). Monte Carlo simulation (100,000 trials) results suggest that the potential lifetime inhalation cancer risks of PAHs were 0.27 × 10(-5) to 7.11 × 10(-5) for park employees, which are in the acceptable range acknowledged by US EPA (1.0 × 10(-6) to 1.0 × 10(-4)). Several source diagnostic methods proved that vehicle exhaust was the dominant PAH contributor of these parks with the contribution percentages being >53%; oil combustion and/or coal combustion were other important sources. Logarithms of gas-particle distribution coefficients (Kps) of PAHs in all studied parks were linearly correlated with those of both their sub-cooled vapor pressures (pLs) and octanol-air partition coefficients (KOAs). The correlation coefficients indicated that both adsorption onto black carbon and absorption into organic matter were involved in the partition process, but the latter was dominant.

Spatial distribution of polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDDs/Fs) in dust, soil, sediment and health risk assessment from an intensive electronic waste recycling site in Southern China.

Workshop dust, soil and sediment samples were collected to investigate the level and spatial distribution of PCDDs/Fs at an intensive electronic waste (e-waste) recycling site in Southern China, and also to characterize the dioxin emission in different e-waste recycling procedures. The concentrations of total PCDDs/Fs ranged from 1866 to 234292 ng kg(-1) for the dust samples, from 3187 to 63998 ng kg(-1) dry wt for the top soils, and 33718 ng kg(-1) for the surface sediment. All the samples were characterized by abnormally high concentrations of OCDD and an extremely low portion of PCDFs. Different e-waste recycling procedures may generate different congener profiles. Open burning and dismantling were the two procedures emitting relatively higher concentrations of PCDDs/Fs in this case, indicating that low-tech recycling operations were one of the major contributors of PCDDs/Fs to the environment. The variation and distinction of the concentrations and homologue/congener profiles among different environmental matrices reveal the characteristics of contaminant environmental behavior and fate during the transportation from "source" to "sink". Daily intake of PCDDs/Fs through soil ingestion and dermal absorption was negligible, but the rough estimated total PCDD/F intake dose far exceeded the tolerance daily intake value of 4 pg-TEQ per kg per day recommended by WHO, indicating that residents in Longtang were at a high risk of exposure to dioxins, especially children.