Distribution Characteristics And Potential Ecological Risks Of Alkylphenols In Estuarine And Coastal Areas

Alkylphenols (APs) are environmental organic pollutants which are harmful to environment and human body. They are persistent organic pollutants that can be transported long-range from source areas. They can be enriched by organisms and are resistant against biodegradation. Particularly, they can induce cancer, gene mutation and hereditaria malformation. With the increasing worsening of the global oceanic and coastal environment, the chemical behaviors of the environmental Persistent Organic Pollutants (POPs) in the coastal environment have attracted much attention in the relevant domestic academic fields. Certain studies were also carried out in some typical urban coastal and estuarine areas in terms of the special distribution and accumulative laws. The estuaries, as the intersectional zone of rivers and the sea, were characterized by complex nature phenomena, high biodiversity and fragile ecosystem due to the multiple nature force between land and ocean and the effect of human activities. This paper took Jiaozhou Bay, the Changjiang River (Yangtze River) Estuary, Bohai Sea and Daliaohe River as the typical study areas. APs are quantified by GC-MS with internal standard, and the distributions, composition, sources, biologic risk assessments in estuarine areas and coastal seas is studied. The deposition fluxes of NP and BPA is estimented according to their distribution characteristics in a dated sediment core in the Changjiang River (Yangtze River) Estuary and its adjacent East China Sea, and the relationship of their deposition fluxes and the economic and social development history in China is also discussed.The paper presents that:In Jiaozhou Bay, the contents of the main Pollutants, nonylphenol (NP), nonylphenol monoethoxylate (NP1EO) and nonylphenol diethoxylate (NP2EO), range from 3.6-219.8 ng/L,60.6-107.9 ng/L and 30.7-79.2 ng/L, respectively. Bisphenol A (BPA) and t-Butylphenol (t-BP) are 1.5-18.1 ng/L and 1.9-2.4 ng/L, whereas t-octylphenol (t-OP) is generally below the detection limit in surface water samples. In all of the surface sediment samples, t-BP and t-OP are below the detection limit. NP,NP1EO,NP2EO and BPA, with the concentrations of 7.1-76.9 ng/g dw,2.8-29.6 ng/g dw,0.9-21.7 ng/g dw and 1.8-3.5 ng/g dw, are detected. The spatial distribution of NP basically indicates that the coastal area is higher than inner bay. Compared with the precise results gained in 2005, the distribution of NP in surface water presented the trend of decrease, whenas the reduction in surface sediments is relatively little.The contents of NP and BPA range from 3.16-13.6 ng/g dw and ND -1.44 ng/g dw, respectively, in all the sediment samples in Bohai Sea. The input of land-sourced pollutants is the main source of NP and BPA, and the circulation system, sediment grain size and particle deposition rate have an importent influence on their spatial ditribution. BPA in surface sediments is much lower than NP.In surface sediments of the Changjiang River (Yangtze River) Estuary, the contents of NP and BPA range from 1.56-35.8 ng/g dw and 0.72-13.2 ng/g dw,respectively, which are not correlated with the distance from the pollution source, and high values are recorded in the two mud zones, the Changjiang River Estuarine Mud Zone and the Zhejiang Coastal Mud Zone. High values in the Zhejiang Coastal Mud Zone are related to the low sedimentation rate and the finer grain size. In sediment core samples, NP and BPA are detected in layers from surface to a depth of 32 cm and 30 cm, respectively. The fluxes show a similar distribution pattern as their concentrations, and basically accord with the economic and social development history in China.In Daliaohe River, the concentrations of NP is higher in the upper reaches and lower in downstream, indicating its pollution source mainly locate at the upper reaches of estuary. NP in bottom water has exceeded that in surface water in 63% of the investigated stations due to high content of suspended solids and the release from sediments. In water samples, significant negative correlations are found between NP and salinity (S), but no correlation is found between NP and dissolved oxygen (DO); In sediment samples, there is significant correlation between NP concentration and total organic carbon (TOC), and no correlation with water content.Compared with other reports of the word, concentration of NP and BPA in all the selectived study areas above is in the moderate or slightly light pollution level, but they have indicated potential risks on local organisms in all the study areas.