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In 2006, organotins pollution were investigated in the coastal environment of Xiamen, China. Six species of organotin compounds including tributyltin, triphenyltin and their degradation compounds were quantified in the dissolved and particulate phases of the water, and in the sediment using GC-FPD. The concentrations of organotin compounds ranged from 2.2 to 160ng (Sn) L−1 dissolved in the water, 0.14–6.7ng (Sn) L−1 in suspended particulate matter and nd∼26ng (Sn) g−1 (dry weight) in the sediment. The highest concentration of total organotin or tributyltin in water was found in a shipyard and at a station near the inlet of the harbor, indicating fresh inputs of antifouling paints to Xiamen’s coastal environment. Organotin speciation was performed on sediment cores to investigate contamination trends over the past ten years in the harbor. The results of 210Pb dating indicated that Xiamen western harbor suffered contamination during 2000. The environmental behavior of organotins such as the enhancement of the microlayer, partitioning between water/suspended particulate matter and between water/sediment are also discussed in this paper. [Copyright &y& Elsevier]

Simulation model is very essential for predicting the environmental fate and the potential environmental consequences of chemical pollutants including those from accidental chemical spills. However very few of such simulation model is seen related to Chinese costal water body. As the first step toward our final goal to develop a simulation model for the prediction and the risk assessment of chemical pollutants in Chinese coastal water, this study developed a three-dimensional (3D) hydrodynamic model of Xiamen Bay (XMB). This hydrodynamic model was externally derived by meteorological data, river discharge and boundary conditions of XMB. We used the model to calculate the physical factors, especially water temperature, salinity and flow field, from June to September 2016 in XMB. The results demonstrated a good match between observations and simulations, which underscores the feasibility of this model in predicting the spatial-temporal concentration of chemical pollutants in the coastal water of XMB. Longitudinal salinity distributions and the mixing profile of river-sea interactions are discussed, including the obvious gradation of salinity from the river towards sea sites shown by the model. We further assumed that 1000 kg and 1000 mg/L of a virtual chemical pollutant leaked out from Jiulong River (JR) estuary (point source) and whole XMB (non-point source), respectively. The model illustrates that it takes three months for XMB to become purified when point source pollution occurs in the estuary, while half a year to be required in the case of non-point source pollution across the entire bay. Moreover, the model indicated that pollutants can easily accumulate in the western coastal zone and narrow waters like Maluan Bay, which can guide environmental protection strategies. Image 1 • Efficient monitoring of the chemical pollutants in the coastal water requires model simulations. • The new hydrodynamic model allows for predicting the environmental fate of chemical pollutants in Xiamen Bay. • Pollutant diffusion estimates point out the difficulties and priorities of environmental governance. • The model largely improves the efficiency of the prevention, treatment and management of environmental contamination issues. • To lay the foundation for future ecological evaluation and risk assessment. [ABSTRACT FROM AUTHOR]

As the last barrier preventing river pollutants from entering the ocean, mangroves have strong absorption and purification abilities, and strong tolerance. We collected mangrove surface water and sediment samples from the Xixi Estuary of Xiamen city. The results showed that the abundance of microplastics in seawater ranged from 620 to 13,100 n/m3, the abundance of microplastics in sediment ranged from 143 to 488 n/kg, the distribution of microplastics was uneven, and the abundance of microplastics in the Xixi Estuary mangrove was significantly higher than that in the non-mangrove area. The sediment column sample results also showed that microplastics were detected in each layer of the sediments, indicating that microplastics were trapped in each layer of mangrove sediments. Therefore, we believe that mangrove forests have an ecological interception effect on microplastics. After entering mangroves, microplastics are affected by tidal reciprocating current scouring, river runoff, sunlight, wind erosion and other factors and gradually break into increasingly smaller particles through physical, chemical and biological effects. Microplastics accumulate in the sediments and experience sedimentation, suspension and reprecipitation processes together with the surface sediments. Mangroves should be widely planted in estuaries to reduce microplastic entry into the ocean. [Display omitted] ● Microplastics were distributed unevenly in mangrove areas. ● The abundance of MPs in mangrove was clearly higher than that in non-mangrove. ● Mangrove forests had a certain ecological interception effect on microplastics. ● Microplastic interception existed in each layer of mangrove sediment. ● MPs form a sedimentation-suspension-reprecipitation process in mangrove. [ABSTRACT FROM AUTHOR]

Twenty-four per- and polyfluoroalkyl substances (PFASs) were analyzed in water and sediment from the Jiulong Estuary-Xiamen Bay to study their seasonal variations, transport, partitioning behavior and ecological risks. The total concentration of PFASs in water ranged from 11 to 98 ng L−1 (average 45 ng L−1) during the dry season, 0.19–5.7 ng L−1 (average 1.5 ng L−1) during the wet season, and 3.0–5.4 ng g−1 dw (average 3.9 ng g−1 dw) in sediment. In water samples, short-chain PFASs were dominated by perfluorooctanoic acid (PFBA) in the dry season and perfluorobutane sulfonate (PFBS) in the wet season, while long chain PFASs, such as perfluorooctane sulfonate (PFOS), dominated in the sediment. The highest concentration of PFASs in water were found in the estuary; in contrast, the highest level of PFASs in sediment were found in Xiamen Bay. These spatial distributions of PFASs indicate that river discharge is the main source of PFASs in estuarine water, while the harbor, airport and wastewater treatment plant near Xiamen Bay may be responsible for the high PFBS and PFOS concentrations in water and sediment. The partition coefficients (log K d) of PFASs between sediment and water (range from 1.64 to 4.14) increased with carbon chain length (R2 = 0.99) and also showed a positive relationship with salinity. A preliminary environmental risk assessment indicated that PFOS and perfluorooctanoic acid (PFOA) in water and sediment pose no significant ecological risk to organisms. • Concentrations and compositions of PFASs in the JEXB had significant seasonal variations. • Short chain PFASs were dominated in water. Long chain PFASs were high in sediment. • PFBA as an alternative increased in water compared with our previous data. • The river discharge, airport, harbor and wastewater treatment plant were the most important sources. • Log K d of PFASs increased with the increasing carbon chain length and salinity. [ABSTRACT FROM AUTHOR]