How polluted is the Yangtze River? Water quality downstream from the Three Gorges Dam

The concentrations of major anions and cations, nitrogen and phosphorus, dissolved and particulate trace elements, and organic pollutants were determined for the middle and lower reaches of the Yangtze River (Changjiang) from below the Three Gorges Dam (TGD) to the mouth at Shanghai in November 2006. The concentration of dissolved inorganic phosphate (DIP) was constant at a low level of 6-8 mu gP/L, but the concentration of nitrate (NO3-) approximately doubled downstream and was closely correlated with K+. This translated to a daily load of well over 1000 It of dissolved inorganic nitrogen (DIN) at Datong. The average concentrations of dissolved Pb (0.078 +/- 0.023 mu g/L), Cd (0.024 +/- 0.009 mu g/L), Cr(0.57 +/- 0.09 mu g/L), Cu (1.9 +/- 0.7 mu g/L), and Ni (0.50 +/- 0.49 mu g/L) were comparable with those in other major world rivers, while As (3.3 +/- 1.3 mu g/L) and Zn (1.5 +/- 0.6 mu g/L) were higher by factors of 5.5 and 2.5, respectively. The trace element contents of suspended particles of As (31 +/- 28 mu g/g), Pb (83 +/- 34 mu g/g), and Ni (52 +/- 16 mu g/g) were close to maximum concentrations recommended for rivers by the European Community (EC). The average concentrations of Cd (2.6 +/- 1.6 mu g/g), Cr (185 +/- 102 mu g/g), Cu (115 +/- 106 mu g/g), and Zn (500 +/- 300 mu g/g) exceeded the EC standards by a factor of two, and Hg (4.4 +/- 4.7 mu g/g) by a factor of 4 to 5. Locally occurring peak concentrations exceed these values up to fourfold, among them the notorious elements As, Hg, and Tl. All dissolved and particulate trace element concentrations were higher than estimates made twenty years ago [Zhang, J., Geochemistry of trace metals from Chinese river/estuary systems: an overview. Estuar Coast Shelf Sci 1995; 41: 631-658.]. The enormous loads of anthropogenic pollutants disposed to the river were diluted by the large water discharge of the Yangtze even during the lowest flow resulting in the relatively low concentration levels of trace elements and organic pollutants observed. We estimated loads of e.g. As, Pb and Ni to the East China Sea to be about 4600 kg As d(-1), 3000 kg Pb d(-1), and 2000 kg Ni d(-1). About 6000 t d(-1) of dissolved organic carbon (DOC) was delivered into the sea at the time of our cruise. We tested for 236 organic pollutants, and only the most infamous were found to be barely above detection limits. We estimated that the load of chlorinated compounds, aromatic hydrocarbons, phenols, and PAHs were between 500 and 3500 kg d(-1). We also detected eight herbicides entering the estuary with loads of 5-350 kg d(-1). The pollutant load, even when at low concentrations, are considerable and pose an increasing threat to the health of the East China Sea ecosystem. (c) 2008 Elsevier B.V. All rights reserved.

Detection and quantitative analysis of polychlorinated biphenyls in tilapia from Hawaiian waters

The purpose of this study was to investigate polychlorinated biphenyls (PCBs) contamination in tilapia (Oreochromis mossambicus) collected from the Manna stream and Ala Wai Canal of O'ahu, an island of the geographically isolated Hawaiian archipelago. Our results show that the average concentrations of PCBs varied from 51.90 to 89.42 ng g(-1) lipid weight for the sampling sites. Relative toxic potencies (RTPs) and toxic equivalencies (TEQs) were determined to be 20.38-40.60 ng TCDD g(-1) lipid weight and 2.89-4.17 ng TEQ g(-1) lipid weight by 7-ethoxy-resorufin-O-deethylase (EROD) activity analysis and calculation of PCB concentrations based on toxic equivalency factors (TEFs), respectively. Penta-chlorinated congeners were found to be predominant, which revealed that Aroclor 1254 was a possible major source of PCBs in our fish samples. PCB 118, an indicator PCBs, constituted more than 55% and 30% of the total PCBs and TEQs, respectively. In addition, PCB 118 was found to have a linear correlation to the total PCBs (R = 0.975) and TEQs (R = 0.782). Detection of concentrated PCBs in Hawaiian waters suggests a potentially adverse impact of this pollutant on human health, as well as ecological systems, and suggests the necessity of environmental monitoring and hazard assessment of PCBs within the Hawaiian Islands. (c) 2008 Published by Elsevier Ltd.

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in surface sediment and bivalve from the Changjiang Estuary, China

Surface sediments and bivalves were collected from the Changjiang Estuary in December 2003 and November 2004, respectively. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in these samples were measured with high-resolution chromatography (HRGC)/High Resolution Mass Spectrometer (HRMS). The concentrations of total PCDD/Fs and toxic equivalent (TEQ) were 169.83 +/- 119.63 and 0.81 +/- 0.36 pg/g dry weight (dw) in sediments, and 580.33 +/- 240.17 and 7.24 +/- 3.65 pg/g dw in bivalves. The homolog compositions of PCDD/Fs were similar among samples, the most abundant congener was octa-chlorinated dibenzo-p-dioxin (OCDD) and then octa-chlorinated dibenzofuran (OCDF) and 1,2,3,4,6,7,8-hepta-chlorinated dibenzo-p-dioxin (HOCDD). The herbicide pentachlorophenol (PCP) and sodium pentachlorophenol (Na-PCP) were proved the main source of PCDD/Fs in this area.

Body loadings and health risk assessment of polychlorinated dibenzo-p-dioxins and dibenzofurans at an intensive electronic waste recycling site in China

This study is one of the very few investigating the dioxin body burden of a group of child-bearing-aged women at an electronic waste (e-waste) recycling site (Taizhou, Zhejiang Province) (24 +/- 2.83 years of age, 40% were primiparae) and a reference site (Lin'an city, Zhejiang Province, about 245 km away from Taizhou) (24 +/- 2.35 years of age, 100% were primiparae) in China. Five sets of samples (each set consisted of human milk, placenta, and hair) were collected from each site. Body burdens of people from the e-waste processing site (human milk, 21.02 +/- 13.81 pg WHO-TEQ(1998/g) fat (World Health Organization toxic equivalency 1998); placenta, 31.15 +/- 15.67 pg WHO-TEQ(1998/g) fat; hair, 33.82 +/- 17.74 pg WHO-TEQ(1998/g) dry wt) showed significantly higher levels of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurnas (PCDD/Fs) than those from the reference site (human milk, 9.35 +/- 7.39 pg WHO-TEQ(1998/g) fat, placenta, 11.91 +/- 7.05 pg WHO-TEQ(1998/g) fat; hair, 5.59 +/- 4.36 pg WHO-TEQ(1998/g) dry wt) and were comparatively higher than other studies. The difference between the two sites was due to e-waste recycling operations, for example, open burning, which led to high background levels. Moreover, mothers from the e-waste recycling site consumed more foods of animal origin. The estimated daily intake of PCDD/Fs within 6 months by breast-fed infants from the e-waste processing site was 2 times higher than that from the reference site. Both values exceeded the WHO tolerable daily intake for adults by at least 25 and 11 times, respectively. Our results implicated that e-waste recycling operations cause prominent PCDD/F levels in the environment and in humans. The elevated body burden may have health implications for the next generation.

Monitoring bioaccumulation and toxic effects of hexachlorobenzene using the polyurethane foam unit method in the microbial communities of the Fuhe River, Wuhan

Hexachlorobenzene (HCB) is a chlorinated aromatic hydrocarbon that was widely used for seed dressing in prevention of fungal growth on crops, and also as a component of fireworks, ammunition, and synthetic rubbers. Because of its resistance to degradation and mobility, HCB is widely distributed throughout the environment and is accumulated through food chains in different ecosystems. In this study, a preliminary investigation was carried out on the bioaccumulation and the toxic effects of HCB in the microbial (protozoan in particular) communities in the Fuhe River, Wuhan, a water body receiving industrial wastewaters containing HCB and other pollutants, using the standardized polyurethane foam units (PFU) method. Field samples were taken from eight stations established along the Fuhe River in January and August 2006. The concentration ratios of HCB in microbial communities and in water were 9.66-18.64, and the microbial communities accumulated 13.29-56.88 mu g/L of HCB in January and 0.82-10.25 mu g/L HCB in August. Correlation analysis showed a negative correlation between the HCB contents in the microbial assemblage, and the number of species and the diversity index of the protozoan communities. This study demonstrated the applicability of the PFU method in monitoring the effects of HCB on the level of microbial communities.

Biodegradation of dibenzofuran by Janibacter terrae strain XJ-1

The dibenzofuran (DF)-degrading bacterium, Janibacter terrae strain XJ-1, was isolated from sediment from East Lake in Wuhan, China. This strain grows aerobically on DF as the sole source of carbon and energy; it has a doubling time of 12 hours at 30 degrees C; and it almost completely degraded 100 mg/L-1 DF in 5 days, producing 2,2',3-trihydroxybiphenyl, salicylic acid, gentisic acid, and other metabolites. The dbdA (DF dioxygenase) gene cluster in the strain is almost identical to that on a large plasmid in Terrabacter sp. YK3. Unlike Janibacter sp. strain YY-1, XJ-1 accumulates gentisic acid rather than catechol as a final product of DF degradation.

Environmental threats to children's health in Southeast Asia and the Western Pacific

The Southeast Asia and Western Pacific regions contain half of the world's children and are among the most rapidly industrializing regions of the globe. Environmental threats to children's health are widespread and are multiplying as nations in the area undergo industrial development and pass through the epidemiologic transition. These environmental hazards range from traditional threats such as bacterial contamination of drinking water and wood smoke in poorly ventilated dwellings to more recently introduced chemical threats such as asbestos construction materials; arsenic in groundwater; methyl isocyanate in Bhopal, India; untreated manufacturing wastes released to landfills; chlorinated hydrocarbon and organophosphorous pesticides; and atmospheric lead emissions from the combustion of leaded gasoline. To address these problems, pediatricians, environmental health scientists, and public health workers throughout Southeast Asia and the Western Pacific have begun to build local and national research and prevention programs in children's environmental health. Successes have been achieved as a result of these efforts: A cost-effective system for producing safe drinking water at the village level has been devised in India; many nations have launched aggressive antismoking campaigns; and Thailand, the Philippines, India, and Pakistan have all begun to reduce their use of lead in gasoline, with resultant declines in children's blood lead levels. The International Conference on Environmental Threats to the Health of Children, held in Bangkok, Thailand, in March 2002, brought together more than 300 representatives from 35 countries and organizations to increase awareness on environmental health hazards affecting children in these regions and throughout the world. The conference, a direct result of the Environmental Threats to the Health of Children meeting held in Manila in April 2000, provided participants with the latest scientific data on children's vulnerability to environmental hazards and models for future policy and public health discussions on ways to improve children's health. The Bangkok Statement, a pledge resulting from the conference proceedings, is an important first step in creating a global alliance committed to developing active and innovative national and international networks to promote and protect children's environmental health.

Patterns and levels of PCDD/F in a Chinese graphite electrode sludge

The graphite electrode sludge was sampled from a huge chloralkali plant in central China. The total level of PCDD/F was found as high as 378.85 mu g/kg sludge (dry weight). The patterns of PCDD/F in each homologue indicated the predominance of tetra- to octa-chlorinated PCDFs, Furthermore, the toxic 2,3,7,8-substituted PCDFs constituted over 80% of the total PCDFs in the sludge and the corresponding PCDDs were only at 15 mu g/kg level. The calculated value of the international toxic equivalence (I-TEQ) in sludge was 21.65 mu g/kg sludge (dry weight). This typical "dioxin chloralkali pattern" was apparently identified in the sediments near the effluent outlet of the chloralkali plant.

PCDD/F-s, PCBs, HCHs and HCB in sediments and soils of Ya-Er lake area in China: Results on residual levels and correlation to the organic carbon and particle size

Sediments and soils collected from the Ya-Er Lake area in China were analysed for the polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyl (PCBs), hexachlorocyclohexane (HCHs) and hexachlorobenzene (HCB). The results indicated the main pollution problems in the Ya-Er Lake area, which was heavily polluted by HCHs and chlorobenzenes, now is dominantly polluted by PCDD/Fs, PCBs and HCB. The occurrence of PCDD/Fs and PCBs with relatively high levels of HpCDDs, OCDD and low chlorinated-substituted PCBs, is attributed to the discharge of waste water and biodegradation. The vertical distributions of HCH-residues are related with the content of organic carbon and particle size. Copyright (C) 1996 Elsevier Science Ltd

Synthesis and properties of two kinds of CPVC carboxylated ionic copolymers

In the present work, two kinds of CPVC carboxylated ionic copolymers were prepared by a new method. First, a graft copolymer (CPVC-cg-AA) comprising of polyacrylic acid (PAA) as branched chains and chlorinated polyvinyl chloride (CPVC) as backbone was synthesized by in-situ chlorinating graft copolymerization (ISCGC). Second, the acid groups of the graft copolymer were neutralized by sodium hydroxide and aluminium hydroxide, respectively in order to prepare carboxylated ionic copolymers.

In situ chlorinating-graft copolymerization on isotactic polypropylene in gas-solid phase

A novel method in situ chlorinating-graft copolymerization (ISCGC) of grafting maleic anhydride (MAH) on isotactic polypropylene (iPP) in gas-solid phase was investigated in this paper. Chlorine (Cl-2) was used as initiator, chlorinating agent and termination agent at the same time during the reaction. The iPP was chlorinated as well as grafted with MAH in the reaction process. The product with chlorine and MAH in the same molecule was named as PP-cg-MAH. Existence of PP-cg-MAH was identified by Fourier transform infrared. Thermal behavior and crystallinity of PP-cg-MAH were analyzed by differential scanning calorimetry, X-ray diffraction and polarizing microscope. Influencing factors for the value of graft degree were also discussed. Compared with conventional peroxide initiated graft method, ISCGC revealed higher MAH graft efficiency (33%), and particularly alleviated degradation of iPP. iPP could be grafted successfully and without changing physical properties dramatically through this method.

A novel approach to synthesis of functional CPVC and CPE or graft copolymers - in situ chlorinating graft

A new process of graft copolymerization of poly(vinyl chloride) (PVC) and polyethylene (PE) with other monomers was developed. The grafted chlorinated poly(vinyl chloride) (CPVC) and chlorinated polyethylene (CPE) were synthesized by in situ chlorinating graft copolymerization (ISCGC) and were characterized. Convincing evidence for grafting and the structure of graft copolymers was obtained using FT-IR, H-1-NMR, gel permeation chromatography (GPC), and the vulcanized curves. Their mechanical properties were also measured. The results show that the products have different molecular structure from those prepared by other conventional graft processes. Their graft chains are short, being highly branched and chlorinated. The graft copolymers have no crosslinking structure. The unique molecular structure will make the materials equipped with special properties.

ENTANGLEMENT FLUCTUATION DURING PHASE-SEPARATION IN POLYMER BLENDS

For perhaps the first time, the dynamics of liquid-liquid phase separation was studied by time-resolved mechanical spectrometry in order to establish the relationship between blends' properties and the phase structures during spinodal decomposition (SD). The selected system was chlorinated polyethylene (CPE)/ethylene-vinyl acetate copolymer (EVA). It was found that in the early and intermediate stage of SD, the storage modulus (G') and the loss modulus (G'') increase with time after the initiation of the isothermal phase separation; in the later stage, G' and G'' decrease as phase separation proceeds. An entanglement fluctuation model was presented to manifest this phenomenon; it was found that the rheological behavior agrees well with the expections of the model in the early stage. For the later stage, the reduction of G' and G'' can be attributed to the increment of phase-domain size. (C) 1993 John Wiley & Sons, Inc.

SEQUENCE STRUCTURE OF ETHYLENE-VINYL SUBSTITUTED COPOLYMER WITH C-13 NMR .4.

The substituent chemical shift (SCS) has been applied to the assignment of the C-13 NMR spectrum of chlorinated polyethylene (CPE). CPE of different chlorine contents has been employed and their sequence structure discussed. The results show that characteristic of CPE with medium chlorine content is the dichloroethane structure in molecular chain. SCS parameters have been obtained from the C-13 NMR spectra. It was found that the effects of chlorine content and temperature on SCS are negligible, but the substituent parameter S1 reduced by 0.39 ppm when C2Cl4 was added to solvent ODCB.

Oxidative destruction of chlorobenzene and o-dichlorobenzene on a highly active catalyst: MnOx/TiO2-Al2O3

A highly active catalyst, MnOx/TiO2-Al2O3, was prepared by impregnating MnOx species on TiO2-modified Al2O3. The TiO2 species in TiO2-Al2O3 support is in a monolayer dispersion, and the MnOx species is again highly dispersed on TiO2-Al2O3 Support. The total oxidation of chlorobenzene and o-dichlorobenzene on MnOx/TiO2-Al2O3 catalyst can be achieved at 300 degreesC and 250 degreesC respectively, at the space velocity of 8000 h(-1). The activity of MnOx/TiO2-Al2O3 catalyst (Mn loading 11.2 wt%) is gradually increased in the first 10-20 h and then keeps stable at least for the measured 52 h at 16,000 h(-1). Furthermore, no chlorinated organic byproducts are detected in the effluent during the oxidative destruction of chlorobenzene and o-dichlorobenzene. It is proposed that the partially chlorinated and highly dispersed manganese oxide on a monolayer TiO2-modified Al2O3 is responsible for the high and stable activity for the total oxidation of chlorinated aromatics. (C) 2001 Academic Press.