Distribution And Ecological Risk Assessment Of PAHs And NP In Sediments From Yangtze Estuary And Its Adjacent Area

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 from the academic society. Studies were carried out in some typical urban coastal and estuarine areas in terms of the distribution and accumulative laws. The Yangtze River Estuary is a major carrying and commercial hinge, lose to highly urbanized and industrialized area. In the last decade, its environment becomes worse and worse, many kinds of contaminants from different sources are inputted. The previous studies have shown that the Yangtze Estuary have been polluted by many kinds of organic contaminant, including alkylphenols (APs), and polycyclic aromatic hydrocarbons (PAHs).PAHs and APs are organic pollutants which are harmful to environment and human health. They are persistent organic pollutants that can be transported long range from source areas. They can be accumulated by organisms and are resistant against biodegradation. Particularly, they can induce cancer, gene mutation and hereditaria malformation. PAHs and APs are also environmental hormones, also called environmental estrogens or endocrine disrupting chemicals (EDCs). They are mainly released to the environment by human activities. They perform similarly to the natural hormones in the human body, so they can produce fault signals and thus interfere with the endocrine system, causing abnormality of the metabolism and endocrine and regeneration system.PAHs and NP are quantified by GC-FID with external standard and GC-MS with internal standard, and the distributions, composition, sources, biologic risk assessments in the surface sediment is studied. The studied area is divided into east-and-west section and south-and-north section by the Yangtze River diluted water, the south-and-north section is divided into three parts: the Yangtze prodelta mud area, the mud area to the southeast of the Yangtze Estuary, Zhejiang coastal mud area.The paper presents that: the concentrations of 16 PAHs in surface sediment varied from 99.6-684.4 ng.g^-1 with an average of 395.7ng.g^-1. The highest sampling station is in the Yangtze prodelta mud area. At the east-and-west section, the concentration of PAHs in the Yangtze Estuary and its adjacent sea area becomes smaller and smaller gradually from coast to offshore. This suggests that the distance from their sources is the important factors effecting the concentrations. At south-and-north section, the distribution pattern of average concentration of PAHs is: the Yangtze prodelta mud area(449.1ng.g^-1)>Zhejiang coastal mud area(436.6ng.g^-1)>the mud area to the southeast of the Yangtze Estuary(395.4ng.g^-1). The distribution pattern of PAHs in the study area is controlled by the distance from their sources, grain-sizes and TOC of surface sediments which are closely related with the circulation system of the Yangtze Estuary and its adjacent sea area. The PAHs in the surface sediments are mainly pyrogenic.The concentrations of NP in surface sediment varied from 0.73-11.45ng.g^-1 with an average of 4.43ng.g^-1. The two highest sampling stations is in the southeast of the Yangtze Estuary and the Zhejiang coastal mud area. At the east-and-west section, the distribution pattern of average concentration of NP in the study area is not clear, but the concentration of NP in the coast is higher than that of the offshore generally. At the south-and-north section, the concentration of NP in the two mud area is similar to each other, the distribution pattern of average concentration of PAHs is: the mud area to the southeast of the Yangtze Estuary >Zhejiang coastal mud area. The distribution of NP is not similar to that of PAHs. This is relate to the property of the substance probably.The overall level of PAHs and NP in the study area is light compared to those of the other areas including some estuaries, bays and shallow continental shelves. However, Fluorene and Acenaphthene of one station exceed the effects range low (ERL) values, which might cause adverse effects on halobios, and other sea area had a low risk.