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Concentrations of Cu, Zn, Cr, As, Cd, Pb and Hg were determined in 153 samples covering 18 fish species collected from Heilongjiang River, China, and the potential health risks to local residents through fish consumption were estimated. Results revealed that all metals were detected with Cd and Pb having considerably lower detection rate. There were 28.6 % of Lethenteron camtschaticum samples exceeding the limit of inorganic As content established by Chinese legislation. Metal bioaccumulation in fish were poorly correlated with fish sizes, and generally tended to increase with trophic levels. The hazard quotient values of all fish species were far below 1 for general population and fishermen. The carcinogenic risk of As in L. camtschaticum for the local fishermen exceeded the acceptable level of 10(-4) rise in cancer rates, but was considered safe given the migratory habits of the fish.

The study was undertaken to assess the contents of heavy metals (Cu, Zn, Cr, Pb, Cd, As and Hg) in sea cucumber (Apostichopus japonicus) juveniles from coastal areas of Bohai and Yellow seas in northern China. Sea cucumber juveniles were collected from twenty commercial hatcheries distributed in five coastal cities. The mean concentrations obtained for heavy metals in mg/kg were as follows: Cu (0.179), Zn (2.634), Cr (0.108), Pb (0.065), Cd (0.161), As (0.372), Hg (0.034). All the mean concentrations were below the maximum residual limits set by Chinese legislation, but As in 10 % samples exceeded the safety threshold. Significant differences in contents of Cr, Pb and Hg were found among the five investigated areas. Overall, the heavy metal levels in sea cucumber juveniles were relatively low and more attention should be paid to toxic metals Pb, Cd, As and Hg in future routine monitoring program.

Field trials were carried out in three provinces of China to study the dissipation and residue of forchlorfenuron in citrus fruits. The results had shown that the degradation rate of forchlorfenuron in citrus fruits followed the first-order kinetics equation C = A∙eBt. The half-lives of forchlorfenuron were 15.8-23.0 days, the final residues of forchlorfenuron in pulp were all ≤0.002 mg/kg, and most of the residues were concentrated in the peel. The risk assessment revealed that no significant potential health risk would be induced by forchlorfenuron in citrus fruits. Therefore, it could be safe to apply forchlorfenuron in citrus fruits, and the results of this study could also be regarded as a reference to the setting of maximum residue limit for forchlorfenuron in citrus fruits in China.

A rapid, simple and reliable analytical method was developed for the determination of cyantraniliprole and its major metabolite J9Z38 in pakchoi and soil by using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The sample preparation approach is known as QuEChERS, which stands for quick, easy, cheap, effective, rugged and safe. Samples were extracted with acetonitrile, and cleaned up with dispersive primary and secondary amine sorbent before analysis by UPLC-MS/MS. The limit of quantitation for cyantraniliprole and J9Z38 was 0.01 mg/kg in both pakchoi and soil. Average recoveries of cyantraniliprole and J9Z38 at three fortified levels (0.01, 0.05, 0.1 mg/kg) ranged from 77.8% to 102.5% with relative standard deviation of 1.6%-8.9%. This method has been applied to the analysis of cyantraniliprole and J9Z38 residues in real pakchoi and soil samples selected from field. The results of the residue dynamic experiment showed that the half-life of cyantraniliprole ranged from 2.9 to 6.4 days in pakchoi and 8.7 to 18.2 days in soil, respectively. The final residual levels of cyantraniliprole in pakchoi and soil from Guangdong and Shanghai were below 0.20 and 0.10 mg/kg, respectively; similarly, the final residual levels of J9Z38 in pakchoi and soil from Guangdong and Shanghai were <0.07 and 0.01 mg/kg. These results will be helpful in setting maximum residue limit guidance for cyantraniliprole in pakchoi in China.

A simple, quick and reliable residue analytical method for flusilazole in apple and soil was developed in this study. The samples were extracted with acetonitrile and determined by liquid chromatography with UV detection. The LOQ of the method was 0.02 mg/kg. The dissipation dynamic and final residues of flusilazole in apple and soil were studied using field trial method. The results of residual dynamics experiment showed that after the apple was treated by flusilazole at treble of recommended high dosage (3.75 g/kg H(2)O), the half-life times of flusilazole in apple and soil were 4.23-7.77 days and 3.04-5.14 days, respectively. Residues of flusilazole in apple at harvest time were all below 0.05 mg/kg at both recommended high dosage and 1.5 times of recommended high dosage.

The analytical method for the residue analysis of a novel herbicide, oxaziclomefone, and its dissipation in soil, water, rice plants and husked rice in rice fields at GAP (Good Agricultural Practices) conditions were studied. Oxaziclomefone residues were determined by GC-NPD. Mean recoveries ranged from 84.4 to 108.2% with relative standard deviations (RSDs) of 2.4 to 17.2% at three different spiking levels for each different matrix. The limits of quantification (LOQ) were found to be 0.01 mg/kg in soil, water, rice plants and husked rice and 0.02 mg/kg in rice hull. The mean half-lives of oxaziclomefone residues in water, soil and rice plants were 11.3, 37 and 4.4 days, respectively. At harvest, soil, straw, rice hull and husked rice samples were found to contain oxaziclomefone below the maximum residue level (0.1 mg/kg) set by Japan and Korea. Following the recommended application method, this herbicide is therefore safe to apply to rice fields.

Mefenoxam is the systemic phenylamide fungicide, which is widely used in controlling phytophthora disease of tomato, cucumber, pepper and watermelon, etc. The dissipation behaviour of mefenoxam residues in watermelons and soils was studied. The whole watermelon, melon flesh and soil matrices of mefenoxam were analyzed by GC-NPD. At three different spiking levels mean recoveries and relative standard deviation from spiked samples in six replicated experiments for each matrix were in the range 89.6-98.2% and 1.5-8.1%, respectively. Under field conditions, mefenoxam dissipation rate was found to be faster in the whole watermelons than in the soils. The results showed that the half lives in whole watermelon and soil from Beijing were 3.9 and 10.0 days, respectively, and the half lives in whole watermelon and soil from Shanxi were 3.7 and 28.4 days.

N-(2-Bromophenyl)-2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamine, compound A, is a highly active herbicide. Field trials indicate that it controls major weeds with a good tolerance on rape by postemergence application. In the present study, it was studied the dissipation behavior of compound A residues in rapes and soils. Analyses were carried out using high performance-liquid chromatography with diode array detection. The limits of detections (LOD) of compound A in rape plant and rape seed samples were 0.03 mg kg(-1) and its in soil was 0.02 mg kg(-1). At three different spiking levels mean recoveries and relative standard deviation (RSD) from spiked samples in five replicated experiment for each matrix were in the range 87.3%-96.4% and 2.9%-8.7%, respectively. The dissipation rate was found to vary with the nature of the studied sample. In soil, half-live were 33 and 25 days in Yunnan and Zhejiang, respectively, while in rape, it was 7.2 and 8.5 days. The residual amounts of compound A in rape and soil samples were below LOD after the recommended dosage and two times dosage. According to the calculation of the ADI of compound A and other data, the result suggest that the MRL for compound A in rape is 1 mg kg(-1).