The slope of the simple linear regression between log10 transformed mercury (Hg) concentration and stable nitrogen isotope values (δ15N), hereafter called trophic magnification slope (TMS), from several trophic levels in a food web can represent the overall degree of Hg biomagnification. We compiled data from 69 studies that determined total Hg (THg) or methyl Hg (MeHg) TMS values in 205 aquatic food webs worldwide. Hg TMS values were compared against physicochemical and biological factors hypothesized to affect Hg biomagnification in aquatic systems. Food webs ranged across 1.7 ± 0.7 (mean ± SD) and 1.8 ± 0.8 trophic levels (calculated using δ15N from baseline to top predator) for THg and MeHg, respectively. The average trophic level (based on δ15N) of the upper-trophic-level organisms in the food web was 3.7 ± 0.8 and 3.8 ± 0.8 for THg and MeHg food webs, respectively. For MeHg, the mean TMS value was 0.24 ± 0.08 but varied from 0.08 to 0.53 and was, on average, 1.5 times higher than that for THg with a...

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Biomagnification of Mercury in Aquatic Food Webs: A Worldwide Meta-Analysis

The recent literature describing polycyclic aromatic hydrocarbons (PAHs) in air, water, soil and sediment, waste sludge, biomonitoring, toxicity, are reviewed. Aspects of sampling, sample preparati...

Polycyclic aromatic hydrocarbons. A review

Studies on seasonal pollution of heavy metals in water, sediment, fish and oyster from the Meiliang Bay of Taihu Lake in China

Pesticide levels and environmental risk in aquatic environments in China--A review.

Health risk assessment of heavy metals and pesticides: A case study in the main drinking water source in Dalian, China.

Analyzing trophic transfer of heavy metals for food webs in the newly-formed wetlands of the Yellow River Delta, China.

To elucidate the distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in coastal wetlands and determine the potential toxicity of PAHs to the food web, we analyzed the concentrations of 16 PAHs in the water, sediments, primary producer, invertebrates, fishes, and birds of the coastal wetlands of the Yellow River Delta. The trophic level of the food web was described using the stable carbon isotopes (δ15C) and nitrogen isotopes (δ15N) in organisms. The sources of the PAHs were evaluated with characteristic ratio methods, and their potential toxicity was analyzed in accordance with toxicity equivalency factors. Results showed that the sediments contain higher amounts of PAHs than does the water. The amount of PAHs in the food web follows the order birds > fishes > invertebrates > primary producer. The amount of PAHs in the organs of birds follows the order kidney > lung > heart > liver > muscle. The PAHs concentration in migratory birds, namely, Ardea purpurea, Larus saundersi, Egretta garzetta, and Cygnus cygnus is higher than that in the resident bird Anas poecilorhyncha. The Yellow River Delta is contaminated to a lesser extent than the other wetlands. The PAHs in the coastal wetlands of the Yellow River Delta originate primarily from a mixture of petroleum and combustion sources. The potential toxicity of these PAHs is of moderate or low level. Thus, reducing the release of PAHs through petroleum and combustion sources is necessary to strengthen the protection of plants and animals in the food web of coastal wetlands.

Polycyclic Aromatic Hydrocarbons in the Food Web of Coastal Wetlands: Distribution, Sources and Potential Toxicity

Efficiency of DECA on ship emission and urban air quality: A case study of China port

Determining factors and parameterization of brake wear particle emission.

Vehicle exhaust emissions have seriously affected air quality and human health, and understanding the emission characteristics of vehicle pollutants can promote emission reductions. In this study, a chassis dynamometer was used to study the emission characteristics of the pollutants of two gasoline vehicles (Euro 5 and Euro 6) when using six kinds of fuels. The results show that the two tested vehicles had different engine performance under the same test conditions, which led to a significant difference in their emission characteristics. The fuel consumption and pollutant emission factors of the WLTC cycle were higher than those of the NEDC. The research octane number (RON) and ethanol content of fuels have significant effects on pollutant emissions. For the Euro 5 vehicle, CO and particle number (PN) emissions decreased under the WLTC cycle, and NOx emissions decreased with increasing RONs. For the Euro 6 vehicle, CO and NOx emissions decreased and PN emissions increased with increasing RONs. Compared with traditional gasoline, ethanol gasoline (E10) led to decreases in NOx and PN emissions, and increased CO emissions for the Euro 5 vehicle, while it led to higher PN and NOx emissions and lower CO emissions for the Euro 6 vehicle. In addition, the particulate matter emitted was mainly nucleation-mode particulate matter, accounting for more than 70%. There were two peaks in the particle size distribution, which were about 18 nm and 40 nm, respectively. Finally, compared with ethanol–gasoline, gasoline vehicles with high emission standards (Euro 6) are more suitable for the use of traditional gasoline with a high RON.

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Qijun Zhang

Papers

Analyzing trophic transfer of heavy metals for food webs in the newly-formed wetlands of the Yellow River Delta, China.

Polycyclic Aromatic Hydrocarbons in the Food Web of Coastal Wetlands: Distribution, Sources and Potential Toxicity

Efficiency of DECA on ship emission and urban air quality: A case study of China port

Determining factors and parameterization of brake wear particle emission.

Comprehensive Analysis of the Pollutant Characteristics of Gasoline Vehicle Emissions under Different Engine, Fuel, and Test Cycles