Toxicity of tributyltin to willow trees.
BACKGROUND
Tributyltin is an organotin compound, used as an antifouling agent in ship paint, with heavy impact on the marine environment. Contaminated dredged harbor sludge is now dumped on land. The toxicity of tributyltin (TBT) to trees has not yet been quantified. Eventually, a vegetation cover on the dumped sludge could be established for the purpose of non-food cash crop production and phytoremediation.


METHODS
The phytotoxicity of tributyltin chloride (TBTCl) and tributyltin hydride (TBTH) was measured at pH 4 and at pH 7 using the willow tree transpiration test. Different pH levels of the nutrient solutions were achieved by adding ammonium salt (low pH) or nitrate (high pH) as nitrogen source.


CONCLUSIONS
At low pH (pH 4), all trees showed symptoms of poor health. Transpiration decreased at concentrations above or equal to 0.1 mg TBTCl/l and 1 mg TBTH/L. The TBT toxicity was more pronounced at pH 7. The trees survived even the highest dose of 10 mg/l TBTCl or TBTH, although their growth and transpiration was strongly reduced.


CONCLUSIONS
In contrast to other organisms, TBTCl and TBTH were less toxic to higher plants.


CONCLUSIONS
The toxicity of TBT is no hindrance for establishing vegetation on TBT-contaminated sludge. Phytoremediation and cash crop production could be possible with suitable plants.
Trapp
Stefan
S
Environment & Resources DTU, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark. stt@er.dtu.dk
Ciucani
Giovannella
G
Sismilich
Milos
M
D004785:Environmental Pollutants / Q000633:toxicity*; D006863:Hydrogen-Ion Concentration; D009566:Nitrates; D009584:Nitrogen; D010150:Paint; D012037:Refuse Disposal; D032108:Salix; D012767:Ships; D018675:Toxicity Tests; D014220:Trialkyltin Compounds / Q000633:toxicity*
D004785:Environmental Pollutants; D009566:Nitrates; D014220:Trialkyltin Compounds; C011559:tributyltin; D009584:Nitrogen