Organochlorine pesticides in ambient air from the littoral cities of northern China: Spatial distribution, seasonal variation, source apportionment and cancer risk assessment.

Concentrations, composition and seasonal variations of organochlorine pesticides (OCPs) in the atmosphere (particulate phase and gaseous phase) at coastal cities in northern China were determined. OCP transport from emission source areas and lifetime excess cancer risks by inhalation exposure to specific OCPs were also investigated. The annual average concentration of total OCPs in gaseous phase ranged from 1.0ng/m3 to 6.3ng/m3, with the peak observed in summer at most sites. Particulate phase concentrations ranged from 29.9pg/m3 to 103.3pg/m3, with the maximum found in the local heating period at most locations. The detection rates of gaseous samples were considerably higher than those of particulate ones. The dominant components included endosulfan (I and II), (α- and γ-) chlordane, pentachlorobiphenyl (PeCB), hexachlorobenzene (HCB), heptachlor, (α-, ß- and γ-) hexachlorocyclohexane (HCH), dichloro-diphenyl-trichloroethane (DDT) and their metabolic products. The specific ratios indicated different applications of DDT, technical HCH and endosulfan at most sites. Large differences in compositional profiles occurred in January (typical heating period) and July (representative non-heating period), and diurnal changes in component concentrations may have been influenced by local emission pattern. The potential source contribution function (PSCF) manifested seasonal concentrations of airborne OCPs affected by the input of potential sources in different regions. The emission sources with higher contribution probabilities to the sites were primarily distributed in the surrounding areas. The lifetime excess cancer risks for the local residents by inhalation exposure to specific components were not high, though the potential threat of α-HCH and HCB should be concerned. CAPSULE: Gaseous OCPs reached peak values in summer and dominated relative to particulate (PM10) values; meanwhile, surrounding sources affected air OCP concentrations, and cancer risks of OCPs by inhalation exposure were not high.

[Recent Distribution and Sources of Polycyclic Aromatic Hydrocarbons in Surface Soils from Yangtze River Delta].

A total of 243 surface soil samples collected from 11 cities in the Yangtze River Delta region were analyzed for the concentrations, spatial distribution, component profiles and emission sources of 29 PAH species. The analytical results indicated the total concentrations of PAHs in Yangtze River Delta fell in the range from 21. 0 ng x g(-1) to 3 578.5 ng x g(-1) with an arithmetic mean and standard deviation of 310.6 ng x g(-1) and 459.1 ng x g(-1), respectively. Our data showed spatial distribution of PAHs concentrations varied greatly in the region. In addition, the contents of PAHs were positively correlated with the total organic carbon fractions in topsoil. The sites with the highest levels of PAHs in the 11 cities studied were located in Suzhou with 759.0 ng x g(-1) +/- 132.9 ng x g(-1) ollowed by the areas of Wuxi and Shanghai, with the total PAHs concentrations of 565. 3 ng x g(-1) +/- 705.5 ng x g(-1) and 349.4 ng g(-1) 220. 1 ng-g(-1) respectively. The profiles of different components pointed to a predominant role of the species with 2-4 rings, and especially for the low molecular weight components with 2-3 rings. A preliminary identification on emission sources of local PAHs was performed by the specific ratios of isomeric species and principal component analysis (PCA). The results designated industrial coal and biomass combustion as the main mixed emission sources of PAHs in surface soils from Yangtze River Delta, and tail gas from transport as another major source in some areas.