Toxicity And Bioaccumulation Of Tributyltin In The Common Algae Of China Coastal Sea

Tributyltin is one of the most toxic contaminants in coastal sea, which can cause severe adverse effects on microalgae even at low concentration. Although Tributyltin was forbidden, its residues in coastal sea might have toxic effects on Algae. Algae cell possesses the ability to accumulate and degrade butyltin compounds. Many researches suggested that biotic degradation by microorganisms such as phytoplankton, bacteria and fungi was the major pathway for removal of TBT in the aquatic environment. Microalgae can tranfer butyltin to zooplankter, shellfish, fish, and so on. It is indispensable to study Bioaccumulation and Biodegradation of butyltin by phytoplankton. Compared to the research of TBT effects on bivalves, gastropods and crustaceans, few papers on toxic effects of TBT on phytoplankton are published.This paper is targeted to study the toxic effects of tributyltin on fifteen common algae in China coastal sea using cell density, peak diameter and photosynthetic activity (Fv/Fm) as response endpoint. EC₅₀ and No Detectation Effect Concentration (NDEC) were determinated to scale the toxic effecs on phytoplankton. The ecological assessment of TBT in Tianjin coastal sea, Jiaozhou Bay, Hongkong coastal sea and Xiamen coastal sea was done by citing references data. The fat content of algae was determined, which may related to the bioaccumulation of TBT in algae cell. The intracellular and extracellular concentrations of organotin compounds was determined by solid phase micro-extraction and gas chromatography-mass spectrometry (GC-MS) in order to study the accumulation, removal and degradation of TBT by Leptocylindru danicus, Amphidinium carterae, Karenia mikimotoi, Asterionella japonica, The main conclusions were as follow;1. TBT was highly toxic to fifteen phytoplankton, the toxic effects of TBT were very different among different phytoplankton species. The TBT tolerance of Leptocylindru danicus was the strongest, and Chaetoceros, Thalassiosira, Gymnodinium simplex, Scrippsiella trochoidea were sensitive to TBT.2. 96h-EC₅₀ of TBT were 136.42μg/L for Leptocylindru danicus, 21.60μg/L for Amphidinium carterae, 7.71μg/L for Karenia mikimotoi, 4.77μg/L for Prorocentrum minimum, 3.81μg/L for Gymnodinium sp., 3.55μg/L for Skeletonema marinoi, 3.15μg/L for Asterionella japonica, 2.95μg/L for Bacilaria paxillifera, 2.04μg/L for Scrippsiella trochoidea, 1.90μg/L for Chaetoceros debilis, 1.76μg/L for Heterosigma akashiwo, 1.08μg/L for Chaetoceros socialis, 0.7μg/L for Thalassiosira, 0.53μg/L for Gymnodinium simplex, 0.51μg/L for Prorocentrum triestinum, respectively. Leptocylindru danicus and Amphidinium carterae were the common red tide algae in China's offshore ports.3. The NDECwere 112.62μg/L for Leptocylindru danicus, 6.28μg/L for Amphidinium carterae, 3.73μg/L for Prorocentrum minimum, 3.70μg/L for Asterionella japonica, 1.98μg/L for Skeletonema marinoi, 1.84μg/L for Karenia mikimotoi, 1.76μg/L for Heterosigma akashiwo, 1.63μg/L for Scrippsiella trochoidea, 1.17μg/L for Bacilaria paxillifera, 1.07μg/L for Chaetoceros socialis, 0.99μg/L for Gymnodinium sp., 0.95μg/L for Chaetoceros debilis, 0.79μg/L for Thalassiosira, 0.23μg/L for Gymnodinium simplex, 0.16μg/L for Prorocentrum triestinum, respectively. According to the data from the published papers, TBT in Tianjin coastal sea, Jiaozhou Bay, Hongkong coastal sea and Xiamen coastal sea might have no toxic effects on algae.4. The cell rigid wall played an important role for bioadsorption of TBT. The kinetics of high TBT accumulation in line with the first-order kinetics. The bioconcentration factor (BCF) of Leptocylindru danicus, Karenia mikimotoi, Amphidinium carterae, Asterionella japonica was 3.86×10³ cm³g^-1, 3.34×10³ cm³g^-1, 1.75×10³ cm³g^-1, 0.90×10³ cm³g^-1respectively. The TBT adsorption ability of a microalgal species was related to the BCF. There was a positive correlation between BCF and 96h-EC₅₀ except Karenia mikimotoi (a wall-less algae). The tested algae could remove TBT in the medium. The Leptocylindru danicus, Amphidinium carterae, Karenia mikimotoi had the ability to biodegrade TBT. 5. The toxic effects of TBT on algae were correlated with the fat content of algae cell. The results indicated that the toxic effecs of TBT increased with the decrease of fat content for algae.