| Organotin compounds have been widely used as anti-bacterial and anti-fungal agents in pesticides, and as heat and light stabilizer in the production of polyvinyl chloride materials and anti-fouling application. The occurrence of Organotin compounds in coastal environments has resulted in toxic effects on non-target organisms such as shellfish and fish, and even at extremely low concentration can cause serve effect. Many concerns have been caused on their concentration Distribution in environment and their ecological risk assessment.This paper is targeted on the most important organotin comtaminants, butyltin compounds. A analytical method was established and optimized that is suitable for seawater and sediment samples. Based on the established analytical method, the concentration distribution of butyltin compounds in Jiaozhou Bay was given and a primary ecological risk assessment of TBT was done by the calculation of risk quotients. Moreover, the effects of tributyltin(TBT) on five algal species which are the dominant groups in the coastal marine area of China were studied in laboratory experiments, EC50 and NDEC were calculated. The main conclusions were as follows:Ⅰ. A analytical method for determination of butyltin compounds in seawater and sediment samples by gas chromatography-mass spectrometry(GC-MS) was developed and optimized. The derivatization and SPME extraction were done simultaneously at 40℃for 30 min in a 0.1mL 4% sodium tetraethylborate solution (pH=4.7). The GC-MS was run at the conditions optimized. The standard of butyltin was determined under the selected chromatographic conditions, the selected ion of MBT was 121, 149,177,235; DBT:121,151,177,207; TBT:121,151,177,207; TeBT: 121,177,235,291.The detection limits in seawater were MBT 11.2ng/L, DBT 2.6 ng/L, TBT 0.6 ng/L with R.S.D values below 14.0%, the recoveries of three organotin compounds was 70.0-124.5%; In sediment, The detection limits were MBT 7.8ng/g, DBT 0.5 ng/g, TBT 0.4 ng/g with R.S.D values below 10.0% and the recoveries of three organotin compounds was 75.4-94.5%. Ⅱ. Based on the developed analytical method, the pollution of butyltin compounds in Jiaozhou Bay was studied.The average concentrations of MBT, DBT and TBT in seawater were 16.7 ng/L, 3.4 ng/L and 4.1 ng/L, respectively; the concentrations of total butyltins(ΣBT) and MBT in the harbor were higher than that in the mouth and central of Jiaozhou bay; The concentration of DBT was relatively low, only a few stations were detected and the highest concentration occurred near the Red Island; In the stations, the concentration of TBT were much different, the highest concentration occurred near the Hercynian Bay.The average concentration of MBT, DBT and TBT in surface sediment were 18.1ngSn/g,0.7 ngSn/g and 0.9 ngSn/g respectively; The concentrations of butyltins in the east were higher than that in the west and north of Jiaozhou bay which may be caused by the heavy traffic near the habors and the discharges of domestic sewages and industry wasterwaters.Ⅲ. Ecological risk assessment of TBT in Jiaozhou bay:According to the investigated data above, the ecology risk of TBT in Jiaozhou Bay were assessed with risk quotient. The results showed that there was much risk to gastropods reproduction, plankton cell division and oyster shell calcification, but less risk to the reproduction of bivalve mollusks relatively. So it is necessary to take some measures to control the butyltin compounds pollution in Jiaozhou Bay.Ⅳ. The toxicity of TBT on five dominant algal species in the coastal marine area of China was determinated in laboratory. The EC50 and NDEC values were obviously different for different algae species. The EC50 was:Skeletonema costatum> Gymnodinium sp.>Choetoceros curvisetus>Prorocentrum micans>Prorocentrum donghainase. The NDEC was:Skeletonema costatum>Gymnodinium sp.> Choetoceros curvisetus>Prorocentrum micans>Prorocentrum donghainase. The relationships between maximum growth rate(μmax), maximum population density(Bf) and cell size under different TBT concentrations were also studied, the TBT changed the relationships betweenμmax, Bf and PD from Allometric curves to the U-shaped or inverse U-shaped ones. |
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