| Abstract: | THE deleterious effect of chlorofluorocarbons on stratospheric ozone has led to international cooperation to end their use. The search for acceptable alternatives has focused on hydrofluorocarbons (HFCs) or hydrochlorofluorocarbons (HCFCs) which are attractive because they have relatively short atmospheric residence times. HFCs and HCFCs are attacked by tropospheric hydroxyl radicals, leading to the formation of trifluoroacetate (TFA). Most of the atmospheric TFA is deposited at the Earth‘s surface, where it is thought to be highly resistant to bacterial attack. Therefore, use of HCFCs and HFCs may lead to accumulation of TFA in soils, where it could prove toxic or inhibitory to plants and soil microbial communities. Although little is known about the toxicity of TFA, monofluoroacetate, which occurs at low levels in some plants and which is susceptible to slow attack by aerobic soil microbes, is known to be acutely toxic. Here we report that TFA can be rapidly degraded microbially under anoxic and oxic conditions. These results imply that significant microbial sinks exist in nature for the elimination of TFA from the environment. We also show that oxic degradation of TFA leads to the formation of fluoroform, a potential ozone-depleting compound with a much longer atmospheric lifetime than the parent compounds.The deleterious effect of chlorofluorcarbons on stratospheric ozone has led to international cooperation to end their use. The search for acceptable alternatives has focused on hydroflnorocarbons (HFCs) or hydrochloroflnorcarbons (HCFs) which are attractive because they have relatively short atmospheric residence times. HFCs and HCFs are attacked by tropospheric hydroxyl radicals, leading to the formation of trifluoroacetate (TFA). Most of the atmospheric TFA is deposited at the Earth‘s surface, where it is thought to be highly resistant to bacterial attack. Therefore, use of HCFs and HCFs may lead to accummulation of TFA in soils, where it could prove toxic or inhibitory to plants and soil microbial communities. Although little is known about the toxicity of TFA, monofluoracetate, which occurs at low levels in some plants and which is susceptible to slow attack by aerobic soil microbes, is known to be acutely toxic. Here we report that TFA can be rapidly degraded microbially under anoxic and oxic conditions. These results imply that significant microbial sinks exist in nature for the elimination of TFA from the environment. We also show that oxic degradation of TFA leads to the formation of fluoroform, a potential ozone-depleting compound with a much longer atmospheric lifetime than the parent compounds. |
| Genre: | Article |
| ProdID: | 70017647 |
| Citation Author: | Visscher, P. T.; Culbertson, C. W.; Oremland, R. S. |
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| Citation End Page: | 731 |
| Citation Issue: | 6483 |
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| Citation Language: | English |
| Citation Larger Work Title: | Nature |
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| Citation Number Of Pages: | 3 |
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| Citation Publisher: | Macmillan Magazines Ltd |
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| Citation Search Results Text: | Degradation of trifluoroacetate in oxic and anoxic sediments; 1994; Article; Journal; Nature; Visscher, P. T.; Culbertson, C. W.; Oremland, R. S. |
| Citation Start Page: | 729 |
| Citation Volume: | 369 |
| Citation Year: | 1994 |
| Type: | citation/reference |
| Text: | Degradation of trifluoroacetate in oxic and anoxic sediments; 1994; Article; Journal; Nature; Visscher, P. T.; Culbertson, C. W.; Oremland, R. S. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1038/369729a0 |
| Date Other: | Sat, 1 Jan 1994 00:00 -0600 |
| Publisher: | Macmillan Magazines Ltd |
