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<h3> <font style="font-weight:bold"> Acid Rain </font> </h3> | <h3> <font style="font-weight:bold"> Acid Rain </font> </h3> | ||
In the lower atmosphere degradation of chlorinated solvents is initiated by a reaction with the hydroxyl radical, and forms a variety of products including hydrochloric acid, formic acid, and phosgene (the colourless gas infamous for its use as a chemical weapon during World War One). These compounds dissolve in cloud and rain water and are ultimately deposited from the atmosphere in acid rain and snow. | In the lower atmosphere degradation of chlorinated solvents is initiated by a reaction with the hydroxyl radical, and forms a variety of products including hydrochloric acid, formic acid, and phosgene (the colourless gas infamous for its use as a chemical weapon during World War One). These compounds dissolve in cloud and rain water and are ultimately deposited from the atmosphere in acid rain and snow. | ||
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| + | Further, trichloroacetic acid (TCA) can be formed as a minor product in the atmospheric deg-radation of some chlorinated solvents. Studies have shown that TCA is broadly distributed in precipitation, surface water and soil on a global scale. Since the observed levels in soil in some areas have been found to exceed the accepted 'safe' levels (2.4 μg/kg for terrestrial organisms) the European Commission instructed producers of the relevant solvents to carry out extensive studies of the origin and fate of environmental TCA. Although the results of these studies suggest that TCA levels in soils could not be explained by precipitation alone, the European Union Risk Assessment on nevertheless concluded that “it is considered unlikely that depo-sition of TCA from the atmosphere will by itself lead to levels of TCA in soil that pose a risk for ter-restrial organisms”. | ||
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<h2>Biosphere</h2> | <h2>Biosphere</h2> | ||
| - | <p> | + | <p>The No Observed Effect Concentration (NOEC) for the most sensitive species of plants was 46 μg/m</p> |
</div> | </div> | ||
Revision as of 10:50, 6 August 2014
Chlorinated Solvents
Uses of Chlorinated Solvents
Eurochlor, the EU body responsible for the European Chlorinated Solvents Association) analyses the uses and impact of chlorinated solvents in three categories: industrial, professional, and consumer. Today the four most commonly used chlorinated solvents are dichloromethane (DCM - also known as methyl chloride [CH2Cl2]), trichloroethylene (aka trichloroethene [C2HCl3]), perchloroethylene (aka tetrachloroethene [C2Cl4]), and to a lesser extent, trichloromethane(aka chloroform[CHCl3]). Hover over each application to reveal more information...
Industrial Uses
Adhesives & Sealants ↴ - Foam Blowing
- Formulation of Preparations
- Intermediate Use Manufacture
- Recycling
- Metal Cleaning
- Decorating
- Extraction Solvent
- Cleaning
- Textile Industry
- Functional Fluid
Coatings and adhesives sometimes require the dissolving power of chlorinated solvents to solubilize the wide variety of thermoplastic ingredients. DCM and trichloroethylene feature rapid drying rates and low flammability that make them ideal for use in rubber cements, styrenics, and epoxies.
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Professional Uses
- Packaging & (Re)-Filling
- Adhesives
- Aerosols
- Laboratory Use
- Manual Cleaning
- Decorating
- Dry Cleaning
- Film Cleaning and Copying
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Consumer Uses
- Aerosols
- Glue (including carpet glue, glue spray, and glue from a tube, super glue, wood parquet glue)
- Decorating
- Washing and cleaning products
- Pest Control
Despite controversies chlorinated solvents remain present in a range of aerosol products including hairspray and deodorant
.Chlorinated solvents are used in a wide variety of adhesive products available to consumers, including carpet glue, spray and tube adhesives, superglue, and wood parquet glue.
Chlorinated solvents are common ingredients in materials such as paint spray and paint stripper - although since 2010 DCM is no longer permitted in home use paint strippers, in part due to problems encountered with disposal, chlorinated solvents continue to be used for this purpose in non-EU countries.
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Chlorinated solvents are used in various plant protection products, both for large-scale agriculture and for home-use, and in other pest control sprays.
Disposal of Chlorinated Solvents
Eurochlor, the EU body responsible for the European Chlorinated Solvents Association) analyses the uses and impact of chlorinated solvents in three categories: industrial, professional, and consumer. Hover over each application to reveal more information...
Atmosphere
There is a possibility that chlorinated solvents may contribute to ozone depletion - the potential for problems to be caused by this is the greater because these solvents are not regulated under the chlorine budget of the Montreal Protocol.
Photochemical Smog
Global Warming
Dichloromethane has a Global Warming Potential (GWP) ten times greater than that of carbon dioxide, whilst trichloromethane has a GWP 30 times greater. At the time of writing the GWPs of tetrachloroethene and trichloroethene are not known, but are expected to be comparable to those for DCM and TCM.Acid Rain
In the lower atmosphere degradation of chlorinated solvents is initiated by a reaction with the hydroxyl radical, and forms a variety of products including hydrochloric acid, formic acid, and phosgene (the colourless gas infamous for its use as a chemical weapon during World War One). These compounds dissolve in cloud and rain water and are ultimately deposited from the atmosphere in acid rain and snow. Further, trichloroacetic acid (TCA) can be formed as a minor product in the atmospheric deg-radation of some chlorinated solvents. Studies have shown that TCA is broadly distributed in precipitation, surface water and soil on a global scale. Since the observed levels in soil in some areas have been found to exceed the accepted 'safe' levels (2.4 μg/kg for terrestrial organisms) the European Commission instructed producers of the relevant solvents to carry out extensive studies of the origin and fate of environmental TCA. Although the results of these studies suggest that TCA levels in soils could not be explained by precipitation alone, the European Union Risk Assessment on nevertheless concluded that “it is considered unlikely that depo-sition of TCA from the atmosphere will by itself lead to levels of TCA in soil that pose a risk for ter-restrial organisms”.Biosphere
The No Observed Effect Concentration (NOEC) for the most sensitive species of plants was 46 μg/m
Groundwater
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Marine Environment
Chlorinated solvents are generally highly volatile and only sparingly soluble in water. Even if traces of solvents are briefly present in aqueous waste streams, they volatilise from rivers and lakes with a half-life of about a month or less, unless they are trapped in groundwater. Nevertheless, presence of chlorinated solvents is a concern due to its potential impact on marine life...
