Dietary exposure to PCBs based on food consumption survey and food basket analysis at Taizhou, China--the world's major site for recycling transformers

The levels of PCBs in different types of food (fish, shellfish, meat, rice, vegetables, and fruits) were analyzed to determine the dietary intake of 37 PCBs for local residents and e-waste workers (all lactating mothers) at Taizhou (China), a major electronic waste scrapping center, in particular for recycling transformers. The exposure to PCBs through dietary intake in Taizhou was estimated at 92.79 ngkg(-1)d(-1), contributed by consumption of freshwater fish (28%), rice (28%), meat (17%), shellfish (9%), vegetables (8%), egg (4%) and marine fish (2%). With regards to WHO-PCB-TEQ values, freshwater fish (40%), shellfish (24%), duck liver (18%) and rice (12%) were the main dietary sources with total daily intake (9.78 pg WHO-PCB-TEQ kg(-1)d(-1)), exceeding the FAO/WHO Tolerable Daily Intake (70 pg TEQkg(-1)body(-1)wt(-1)month(-1)).     

Polybrominated diphenyl ethers in plastic products,indoor dust,sediment and fish from informal e-waste recycling sites in Vietnam: a comprehensive assessment of contamination,accumulation pattern,emissions, and human exposure

Residue concentrations of polybrominated diphenyl ethers (PBDEs) in different kinds of samples including consumer products, indoor dust, sediment and fish collected from two e-waste recycling sites, and some industrial, urban and suburban areas in Vietnam were determined to provide a comprehensive assessment of the contamination levels, accumulation pattern, emission potential and human exposure through dust ingestion and fish consumption. There was a large variation of PBDE levels in plastic parts of obsolete electronic equipment (from 1730 to 97,300 ng/g), which is a common result observed in consumer plastic products reported elsewhere. PBDE levels in indoor dust samples collected from e-waste recycling sites ranged from 250 to 8740 ng/g, which were markedly higher than those in industrial areas and household offices. Emission rate of PBDEs from plastic parts of disposed electronic equipment to dust was estimated to be in a range from 3.4 × 10^?7 to 1.2 × 10^?5 (year^?1) for total PBDEs and from 2.9 × 10^?7 to 7.2 × 10^?6 (year^?1) for BDE-209. Some fish species collected from ponds in e-waste recycling villages contained elevated levels of PBDEs, especially BDE-209, which were markedly higher than those in fish previously reported. Overall, levels and patterns of PBDE accumulation in different kinds of samples suggest significant emission from e-waste sites and that these areas are potential sources of PBDE contamination. Intakes of PBDEs via fish consumption were generally higher than those estimated through dust ingestion. Intake of BDE-99 and BDE-209 through dust ingestion contributes a large proportion due to higher concentrations in dust and fish. Body weight normalized daily intake through dust ingestion estimated for the e-waste recycling sites (0.10–3.46 ng/day/kg body wt.) were in a high range as compared to those reported in other countries. Our results highlight the potential releases of PBDEs from informal recycling activities and the high degree of human exposure and suggest the need for continuous investigations on environmental pollution and toxic impacts of e-waste-related hazardous chemicals.     

Ecological Survey of Coastal I Water Adjacent to Nuclear Power I Plants in Taiwan

A total of six nuclear reactors installed in three power plants, two along the northern and one along the southern coasts of Taiwan, started their operations one after another since October 1977. Owing to the large quantities of cooling water intake into and discharge from the plants, some environmental factors such as water temperature, chlorine, environmental radioactivity and nearshore currents may be significantly changed. Variations of these abiotic environmental factors may influence the biological activities in the ecosystem, particularly doing some kinds of damage to marine biological resources. Therefore, the possible environmental impact upon the biological systems including the fishery resources along the northern and southern coasts of Taiwan should be studied before and during the plant operation.

We have started the long-term programmes of biological, chemical and hydro-graphical surveys of the nuclear power plant sites on both northern (since July 1974) and southern (since July 1979) coasts of Taiwan. the survey items include ocean currents, physical and chemical properties of sea water, primary productivity, specific compositions and interspecific relationships among phyto- and zooplankton, algae, invertebrates, corals, and fishes; and radionuclides in water and biological specimens, and fishery statistics. in general, except for a few events, the operations of the six units of nuclear power plants have not produced detectable effects on the marine ecosystem. Radio activity levels and radionuclides in water and the biological specimens remained the same as background levels throughout the survey period. However, the events of coral bleaching and fish body anomalies caused by thermal discharges were observed respectively along the outlets of third and second Nuclear Power Plants. the purposes of this paper are to report and evaluate these two events during the operations of nuclear power plants in Taiwan.     

Urban water infrastructure optimization to reduce environmental impacts and costs

Urban water planning and policy have been focusing on environmentally benign and economically viable water management. The objective of this study is to develop a mathematical model to integrate and optimize urban water infrastructures for supply-side planning and policy: freshwater resources and treated wastewater are allocated to various water demand categories in order to reduce contaminants in the influents supplied for drinking water, and to reduce consumption of the water resources imported from the regions beyond a city boundary. A case study is performed to validate the proposed model. An optimal urban water system of a metropolitan city is calculated on the basis of the model and compared to the existing water system. The integration and optimization decrease (i) average concentrations of the influents supplied for drinking water, which can improve human health and hygiene; (ii) total consumption of water resources, as well as electricity, reducing overall environmental impacts; (iii) life cycle cost; and (iv) water resource dependency on other regions, improving regional water security. This model contributes to sustainable urban water planning and policy.     

Optimal methods to determine the physical parameters for activated carbon adsorption

The objectives of this research were to examine the physical characteristics of activated carbons made of different materials, thereby suggest a preferable approach to obtaining the optimal estimation of the parameters for the activated carbons by the statistical techniques. After the appropriate pretreatments, the apparent and true densities of activated carbon, adsorption isotherms of argon, nitrogen and mercury, and the adsorptive capacity of benzene were determined by using the recommended approaches. The results showed that the shapes of hysteresis loop indicated that the pores were probably slit‐shaped or formed by plate‐like particles, which could be confirmed by the SEM examination. It was noted that the apparent density used for pore volume calculation presented a higher possibility of underestimation. Through the use of the statistical techniques, such as factor analysis (FA) and correspondence analysis (CA), the principal physical parameters on adsorption phenomena could be characterized. Finally, the optimal methods for obtaining the surface area and pore volume of activated carbons were suggested.     

Health risk of aerosols and toxic metals from incense and joss paper burning

We report for the first time the distribution and hazard potential of aerosol and metals resulting from joss paper burning. Burning joss paper and incense is a traditional custom in many Oriental countries. Large amounts of air pollutants, including particles, polycyclic aromatic hydrocarbons, toxic metals and other gaseous pollutants, are released into the environment during the burning stage. Many investigations have reported on the emission of pollutants from the incense burning. However, no work has been reported until now on the analysis of the released pollutants apart from polycyclic aromatic hydrocarbons. In this study, a micro-orifice uniform-deposit impactor and inductively coupled plasma optical emission spectrometry were, respectively, used to collect aerosols and characterize the toxic metals from joss paper burning. We studied two types of particulate matter (PM): PM_2.5 that are particles with a diameter smaller than 2.5 μm and PM₁₀ that are particles with a diameter smaller than 10 μm. PM_2.5 are the most potentially toxic particles. Our results showed that PM_2.5 are the major component of the pollutants and that the PM_2.5 to PM₁₀ ratio ranged from 62 to 99%. The metals Na, Ca, Mg, Al and K were the main species in the aerosol and in the bottom ash.     

Catalytic oxidation of gaseous PCDD/Fs with ozone over iron oxide catalysts

Catalytic oxidation of PCDD/Fs (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans) with ozone (catalytic ozonation) over nano-sized iron oxides (denoted as FexOy) was carried out at temperature of 120-180 degrees C. The effects of operating temperature, ozone concentration, space velocity (SV) and water vapor contents on PCDD/F removal and destruction efficiencies via catalytic ozonation were investigated. High activity of the iron oxide catalyst towards PCDD/F decomposition was observed even at low temperatures with the aid of ozone. The PCDD/F removal and destruction efficiencies achieved with FexOy/O3 at 180 degrees C reach 94% and 91%, respectively. In the absence of ozone, the destruction efficiencies of all PCDD/F congeners are below 20% and decrease with increasing chlorination level of PCDD/F congener at lower temperature (120 degrees C). However, in the presence of ozone, the destruction efficiencies of all PCDD/F congeners are over 80% on FexOy/O3 at 180 degrees C. Higher temperature and ozone addition increase the activity of iron oxide for the decomposition of PCDD/Fs. Additionally, in the presence of 5% water vapor, the destruction efficiency of the PCDD/Fs is above 90% even at lower operating temperature (150 degrees C). It indicates that the presence of appropriate amount of water vapor enhances the catalytic activity for the decomposition of gas-phase PCDD/Fs.     

The organic contamination level based on the total soil mass is not a proper index of the soil contamination intensity

Concentrations of organic contaminants in common productive soils based on the total soil mass give a misleading account of actual contamination effects. This is attributed to the fact that productive soils are essentially water-saturated, with the result that the soil uptake of organic compounds occurs principally by partition into the soil organic matter (SOM). This report illustrates that the soil contamination intensity of a compound is governed by the concentration in the SOM (C_om) rather than by the concentration in whole soil (C_s). Supporting data consist of the measured levels and toxicities of many pesticides in soils of widely differing SOM contents and the related levels in in-situ crops that defy explanation by the C_s values. This SOM-based index is timely needed for evaluating the contamination effects of food crops grown in different soils and for establishing a dependable priority ranking for intended remediation of numerous contamination sites.