Chen Wei-qi

Determination and load of organophosphorus and organochlorine pesticides at water from Jiulong River Estuary, China

Seventeen organic phosphorus pesticides (OPs) and 18 organic chlorine pesticides (OCs) at water from Jiulong River Estuary (JLRE) are determined by SPE-GC-(FPD and microECD). The contents of the total OPs (17) ranged from 134.8 to 354.6 ng/l (the mean is 227.2 ng/l). Total OCs concentrations varied from 115.4 to 414.7 ng/l in water (mean 237.7 ng/l). The levels of total hexachlorocyclohexane in water varied from 31.95 to 129.8 ng/l (mean 62.51 ng/l), and those of total DDTs were in the range 19.24-96.64 ng/l (mean 48.69 ng/l). The distribution and behavior characteristics of OPs indicate that five main OPs (methamidophos, dichlorvos, malathion, omethoate and dimethoate) occupied the most part of the total OPs, in addition, the sources of the OPs (mainly from current usage) are not stable. While the OCs mainly came from early application and were more stable. The OPs did not have obvious correlation with the dissoved organic carbon and suspended particulate matter at water from JLRE. It maybe due to the complicated hydrological kinetics in the estuary, and the higher water solubility and weak absorption (with organic matter) action of OPs. When compared with other areas, the OPs and OCs level in JLRE are some moderate.

Persistent organochlorine residues in sediments of Hong Kong Victoria Harbour and Xiamen Western Bay

Samples of surface sediment were collected from Victoria Harbour, Hong Kong (Aug. 1992), and Xiamen Western Bay (Nov. 1993), and analysed for organochlorine (OC) pesticides (HCHs, DDTs) and polychlorinated biphenyls (PCBs). Concentration ranges of HCHs, DDTs and PCBs in the survey area of Victoria Harbour were from undetectable to 9.4 μg/kg, 1.38–97 μg/kg and 3.2–81 μg/kg, respectively; those for Xiamen Western Bay were 0.14–1.12 μg/kg, 4.45–311 μg/kg and 0.05–7.24 μg/kg, respectively. The determined residue levels and distribution patterns of these organochlorines are discussed, and the Harbour and Bay contamination levels are compared. Two sediment cores were collected (Oct. 1994) from Xiamen Western Bay for study on the vertical profiles and pollution history of the above contaminants. The vertical profile characteristics indicated that the inner part of Xiamen Western Bay was once polluted by PCBs moderately and that there are still new inputs of DDT.

THE BIOGEOCHEMISTRY OF PHOTOSYNTHETIC PIGMENTS IN THE JIULONG RIVER ESTUARY AND WESTERN XIAMEN BAY

High performance liquid chromatography (HPLC) analysis of photosynthetic pigments in samples from Western Xiamen Bay and the Jiulong River Estuary showed that their major carotenoids were fucoxanthin, peridinin, zeaxanthin, violaxanthin, and diadinoxanthin. Diatoms dominated in the spring bloom, dinoflagellates in summer. Violaxanthin and chlorophyll b indicated the appearance of chrysophytes and green algae, most of which were freshwater species. The high phytoplankton biomass region was located at the inner part of the bay. Diatoms and dinoflagellates dominnated phytoplankton communities, contributing to over 50% of total biomass. All the main diagnostic carotenoids were significantly (P<0.01) correlated negatively to dissolved inorganic phosphorus, suggesting that they were limited by phosphorus. The high negative linear relationship (P<0.0001) between dissolved inorganic phosphorus and peridinin (dinoflagellates indicator) implied the potential of dissolved inorganic phosphorus for triggering red tide events in this region.

Copper accumulation and transport in a marine food chain composed of Platymonas subcordiformis, brachionus plicatilis and Penaeus monodon

Accumulation, transport and toxicity of Cu in the food chain consisting ofPlatymonas subcordiformis, Brachionus plicatilis andPenaeus monodon were studied. Effects of Cu on the growth of organisms in the food chain were investigated and the inhibiting effect concentration (EC50) of Cu was then determined according to the dynamics of the relative number of cells or total individuals of organisms, expressed in percentages with reference to the controlled system, under different culture conditions. On the basis of the variations in accumulation and percentages of accumulation of Cu in the biological phase, the relationship between the accumulation of Cu in organisms and its toxicity was analyzed and the main approach for determining the transport of Cu in the food chain was then discussed.

Strategic Environmental Assessment: A New Tool for Ecological Urbanization of Coastal Cities in China

Abstract Recently, there has been growing concerns about environmental issues related to urbanization in China. The intense natural resources utilization and increasing population has brought great pressure, especially in coastal areas, consequently affecting the sustainable development of coastal cities. In 2002, Environmental Impact Assessment Act (EIA Act) was enacted in China. Environmental impact assessment targeted at planning, one level of strategic environmental assessment (SEA), thus became a legislative requirement. This paper considers SEA to be one of the important approaches not only to control coastal pollution, but also to conserve coastal ecosystems and finally to achieve sustainable development during urbanization, thus it will be a set an example for other areas of China. The experience of SEA in Xiamen, a coastal city in southeast China, illustrates the potentials of SEA. This paper first briefly introduces the concept and potentials of SEA, then compares two SEA cases and a project EIA case in Xiamen, and finally identifies the key characteristics of SEA.

Distribution and composition of PAHs in surface waters, porewater and sediments from Xiamen Western Bay

Xiamen Westem Bays water and sediment quality were studied by determining the levels of sixteen polycyclic aromatic hydrocarbons (PAHs) in water, porewater and sediment samples from nine locations in the bay. Total PAH concentrations varied from 106 to 945 ng/l in water, below detection to 3548 ng/l in porewater, and 247 to 480 ng/g dry weight in surface sediments. PAHs levels in porewater were higher than those in surface water, due to the preference of these hydrophobic compounds for sedimentary phase instead of water. Such a concentration gradient implies a potential flux of pollutants from sediments to overlying water. The PAHs levels in sediments were one to several orders of magnitude lower than those in 1993, suggesting their decreased input in recent years and possible degradation with time.

THE VERTICAL DISTRIBUTIONS AND SOURCES OF PAHs IN SEDIMENT OF XIAMEN BAY

This study on the vertical distributions and sources of sixteen PAHs in Xiamen Bay after their separation and determination in sediment cores from No. 1 and No. 5 Stations, showed that PAHs concentrations varied from 158 to 337 ng/g dry weight, and that ΣPAHs varied from 1.1 to 6.0 μg/g. The vertical concentration distributions at No. 1 Station varied slightly (average of 16 PAHs, 242 ng/g; ΣPAHs 1.9 μg/g), except for a maximum at the depth of 3–6 cm (317 ng/g and 2.9 μg/g). The vertical concentration distribution at No. 5 Station changed irregularly, and there was also a maximum at the depth of 30–33cm (337 ng/g, 6.0 μg/g). No. 5. Station (in the inner bay) was much more contaminated by PAHs than No. 1 Station (in the inlet of the bay). The concentrations of PAHs in Xiamen Bay were much lower than the average in the coasts of the world. The sources of PAHs in Xiamen Bay were mainly urban discharge, industry and combustion of fuels.