A total diet study to estimate PCDD/Fs and dioxin-like PCBs intake from food in Taiwan

Concentrations of 17 dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and 12 dioxin-like polychlorinated biphenyls (dl-PCBs) were measured in total diet study samples of 14 food groups of animal origin from 11 locations in Taiwan, collected in 2003. Pork meat possessed the lowest background concentration level of 0.058 pg WHO-TEQ(PCDD/Fs+dl-PCBs)/g fresh weight. The dl-PCBs contribution were 31%, 59%, 36%, 46%, and 13% for meat and meat products, muscle meat of fish, milk and dairy products, fat and oil, and egg, respectively. The estimated monthly intake (EMI) was 44.7 and 39.5 pg WHO-TEQ(PCDD/Fs+dl-PCBs)/kg b.w./month for a male and female adult weighing 64.8 kg and 56.3 kg, respectively. Muscle meat of fish contributes 46% to the mean EMI. Factors affecting the EMI, in order of increasing importance are analytical method uncertainty, sample compositional difference, and food consumption data. In addition to the continuous efforts to identify and reduce the source of PCDD/Fs and dl-PCBs releases into the environment and the food-chain, the practice of a healthy dietary habit, i.e., eating foods of lower TEQ levels, was suggested to effectively reduce human exposure to PCDD/Fs and dl-PCBs.     

Spatial distribution and multiple sources of heavy metals in the water of Chaohu Lake,Anhui, China

In this study, a survey for the spatial distribution of heavy metals in Chaohu Lake of China was conducted. Sixty-two surface water samples were collected from entire lake including three of its main river entrances. This is the first systematic report concerning the content, distribution, and origin of heavy metals (Cu, Cr, Cd, Hg, Zn, and Ni) in the Chaohu Lake water. The results showed that heavy metals (Cu, Cr, Zn, and Ni) concentrations in the estuary of Nanfei River were relatively higher than those in the other areas, while content of Hg is higher in the southeast lake than northwest lake. Moreover, Cd has locally concentration in the surface water from the entire Chaohu Lake. The heavy metal average concentrations, except Hg, were lower than the cutoff values for the first-grade water quality (China Environment Quality Standard) which was set as the highest standard to protect the social nature reserves. The Hg content is between the grades three and four water quality, and other heavy metals contents are higher than background values. The aquatic environment of Chaohu Lake has apparently been contaminated. Both the cluster analysis (CA) and correlation analysis provide information about the origin of heavy metals in the Lake. Our findings indicated that agricultural activities and adjacent plants chimneys may contribute the most to Cd and Hg contamination of Chaohu Lake, respectively.     

Estimating stray dog populations with the regression method versus Beck’s method: a comparison

Statistical procedures for wildlife population estimation have been greatly improved since the last decade. For estimation of stray dog population size, however, the simple methods recommended by the 1990 WHO/WSPA guidelines seem to remain the popular favorites among researchers. Although the methods are very easy to use, their usefulness relies heavily on certain assumptions that are generally unrealistic. Using simulation studies, we conclude that Beck’s method, one of the estimators recommended by the guidelines, performs fairly well and can be safely used to get a quick population estimate, as long as the underlying assumptions are not severely violated.     

Screening plant species native to Taiwan for remediation of 137Cs-contaminated soil and the effects of K addition and soil amendment on the transfer of 137Cs from soil to plants

This study aims to screen plant species native to Taiwan that could be used to eliminate (137)Cs radionuclides from contaminated soil. Four kinds of vegetables and two kinds of plants known as green manures were used for the screening. The test plants were cultivated in (137)Cs-contaminated soil and amended soil which is a mixture of the contaminated one with a horticultural soil. The plant with the highest (137)Cs transfer factor was used for further examination on the effects of K addition on the transfer of (137)Cs from the soils to the plant. Experimental results revealed that plants cultivated in the amended soil produced more biomass than those in the contaminated soil. Rape exhibited the highest production of aboveground parts, and had the highest (137)Cs transfer factor among all the tested plants. The transfer of (137)Cs to the rape grown in the soil to which 100 ppm KCl commonly used in local fertilizers had been added, were restrained. Results of this study indicated that rape, a popular green manure in Taiwan, could remedy (137)Cs-contaminated soil.     

Flesh or bone? Quantifying small-scale coral morphology using with-tissue and without-tissue techniques

The quantification of small-scale coral morphology using tissue-free skeletons often requires colonies, or colony sections, to be removed from the reef. This undesirable destruction can be reduced by using a with-tissue technique based on photographic images of living corals. The results of this study indicate that with-tissue multivariate morphometric data contain similar information to skeleton-derived data and can help identify phenotypic plasticity in the massive coral Favia speciosa. With-tissue data can also be used to discern changes with time in individual polyps exposed to new environments.Communicated by O. Kinne, Oldendorf/Luhe     

Levels of PCDD/FS in ambient air and soil in the vicinity of a municipal solid waste incinerator in Hsinchu

Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined in twenty-one ambient air samples, eight soil samples and two stack gas samples, collected near or in a municipal solid waste incinerator (MSWI) in Hsinchu, Taiwan. A systematic decrease of PCDD/Fs in the ambient air from the northeastern area was observed. PCDD/Fs levels measured in the ambient air range from 0.058 to 0.127 pg-TEQ/m3. Higher PCDD/Fs levels in the ambient air were found during winter. In addition, PCDD/Fs levels measured in the soil range from 0.524 to 5.02 pg-TEQ/g d.m. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) did not provide sufficient evidence that the environmental PCDD/Fs contamination was caused by emissions from the Hsinchu MSWI. An unknown PCDD/Fs source was proposed using congener profile analysis and supported by both PCA and HCA.     

Comparative granule characteristics and biokinetics of sucrose-fed and phenol-fed UASB reactors

Two upflow anaerobic sludge bed (UASB) reactors were fed with a non-inhibitory substrate sucrose and an inhibitory substrate phenol, respectively, to compare granule characteristics and biokinetics. The average size of biomass granules in the sucrose-fed UASB reactor was slightly larger than that of the phenol-fed reactor. The average microbial density was significantly higher in the phenol-fed reactor. The intrinsic biokinetics of sucrose-acidogenesis and phenol-acidogenesis followed Monod and Haldane kinetics, respectively. By comparing half-saturation constants for sucrose and phenol (Ks1,s; Ks1,p), the affinity of phenol to the granule should be much higher. The mass fraction of methanogens (f) in the sucrose-fed reactor decreased with increasing volumetric loading rate (VLR) because of the accumulation of volatile fatty acids (VFAs); the f of the phenol-fed reactor decreased with increasing VLR because acidogenesis was the rate-limiting step. The mass transfer resistance in overall substrate removal in the sucrose-fed reactor was greater than that in the phenol-fed reactor.     

Heavy Metal Levels in Marine Sediments of Singapore

Marine environmental levels of the metals copper (Cu), zinc (Zn), lead (Pb) and cadmium (Cd) were measured from sediments collected around 20 coastal locations around Singapore, over a 2-year period. Sediment-size analysis was conducted on sediment samples, and Atomic Absorption Spectrophotometry was used in the analyses of sediment heavy metal concentrations. The levels of heavy metals in marine sediment was largely dependant on sediment particle size, as illustrated by the correlation of sediment size with Multidimensional Scaling (MDS) configurations of sediment metal concentrations. In addition, the proximity to shipping activity, and the release of anti-fouling paint from boats also influence heavy metal concentrations in marine sediments of Singapore.     

Estimating the change of porosity in the saturated zone during air sparging

Introduction A ir sparging rem oves volatile organic conta- m inants from a saturated zone by com bining volatilization and aerobic biodegradation. A ir is injected below the w ater table through a slotted screen in a sparging w ell, and then rises to the…