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

Abstract

AbstractTo 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.