[Sorption and absorption of PAHS to rice roots].

Intact rice roots, ambient air, soil and irrigation water samples were collected from two sites at Baodi and Xinli, Tianjin. The rice roots were separated into nodal roots and lateral roots, which were extracted individually using a three-step sequential extraction procedure to measure the sorbed, strongly sorbed and interior adsorbed fractions. The results show that remarkable difference of PAH contents between the samples from the two sites and relatively higher PAH contents in the lateral roots than those in the nodal roots, around 60% of the total PAHs detected were those absorbed in the root tissues. Specific surface area and lipid content of the roots are main factors influencing PAH contents.

Persistent organochlorine residues in sediments of Haihe River and Dagu Drainage River in Tianjin, China.

Persistent organochlorine compounds were analyzed by means of GC-ECD in surface sediment samples from two selected rivers in Tianjin, Haihe River and Dagu Drainage River. A total of 16 surface sediment sites were selected along the both rivers. The frequency of detection of T-HCH and T-DDT in sediment samples both was up to 100%, which illustrated that the contamination of HCH and DDT was widespread in Haihe and Dagu Drainage Rivers. Results indicated that the concentrations of various pesticides in sediments from Haihe River were in the range of 3.30-75.96 ng/g dw for T-HCH and 1.57-211.57 ng/g dw for T-DDT. Compared with Haihe River, Dagu Drainage River was contaminated by HCHs and DDTs along the all locations and the values of T-HCH and T-DDT residues in sediments ranged from 2.30 to 124.61 ng/g dw and from 11.28 to 237.30 ng/g dw, respectively. The possible pollution sources were analyzed through monitoring results of organochlorine pesticides(OCPs) residues in sediments from the two rivers. The investigation also indicated that HCH was still used as pesticide in Tianjin partial area.

[Multi-scale spatial relations of PAHs and soil properties in Tianjin area].

Polycyclic aromatic hydrocarbons(PAHs) in soil have serious latent danger to our human health. Based on the sampling data, the spatial scale-dependent correlations of PAHs content and some soil properties are analyzed by Factorial Kriging for top soil in Tianjin area. Based on 1 88 topsoil samples in Tianjin area, pH, TOC, CLAY and sum of 16prior PAHs are tested. Resultsshow that significant difference on spatial correlations at different spatial scales between the PAHs content and soil properties such as pH, TOC and CLAY existed in the studies area.

[PAHs in airborne particles from Tianjin in winter season].

Total suspended particles (TSP) samples from 13 stations in Tianjin were collected and analyzed for polycyclic aromatic hydrocarbons (PAHs) during 2002 winter. There was significant difference in total PAH concentration among 13 samples. TSP samples from the east Economic Development Area and mid-north districts had the highest contents of PAHs, while Dagang Oil Field had the lowest PAH content. The urban area, south district, and Jixian county had the moderate contents of PAHs. Based on the measured concentration of the PAHs, BaP equivalent (BaPeq) were derived based on Toxicity Equivalent Factors (TEFs) of the PAHs. The total BaPeq values were similar among the samples. The contribution of PAHs with five or six rings contributed 90% of the total toxicity, while they accounted for only 50% of the total concentration.