Contaminated surface

Sulfur mustard reacts rapidly with chlorine or with bleach, and this reaction is a suitable means of decontamination. Nitrogen mustards, however, chlorinate extremely slowly thus chlorination is not suitable for their decontamination. The formation of water-soluble salts, such as by neutralization with sodium bisulfate, is the usual method for nitrogen mustard removal from contaminated surfaces. The mustard salts are much less vesicant than the corresponding free bases. 

One such decontaminant is supertropical bleach (STB). STB is a mixture of chlorinated lime and calcium oxide containing about 30% available chlorine. It can be used either as a dry mix or as a slurry to decontaminate some equipment surfaces and terrain. The dry mix is prepared with two parts bleach to three parts earth by volume. A slurry typically consists of 40 parts STB to 60 parts by weight of water. This material is then sprayed or swabbed on the contaminated surface (see Bleaching agents). STB is an effective decontaminant for mustard, lewisite, and VX. It is less effective against nerve agents other than VX. 

Another exception to the rule of contaminated surfaces involves very small particles, generally referred to as nanoclusters. These are generally formed and the adhesion of the.se particles to substrates studied in situ, under ultrahigh vacuum conditions. Owing to the vacuum and the short existence of these particles prior to deposition, it is possible for chemistry to occur. 

Alternatively, the contaminated surface drainage must be segregated from the normal storm water drains and may, for example, be led into a balancing tank. This tank must be large enough to even out the variations and to allow the contents to be added to the works effluent (treated or untreated) over a period of time. Provision must be made for periodically removing the inevitable accumulation of silt in the bottom of the tank. 

The aspect of sample preparation and characterization is usually hidden in the smallprint of articles and many details are often not mentioned at all. It is, however, a very crucial point, especially with surface and interface investigations since there might be many unknown parameters with respect to surface contaminations, surface conformations, built-in stresses, lateral sample inhomogeneities, roughness, interfacial contact etc. This is in particular important when surfaces and interfaces are investigated on a molecular scale where those effects may be quite pronounced. Thus special care has to be taken to prepare well defined and artifact free specimens, which is of course not always simple to check. Many of these points are areas of... 

Methyl parathion can enter your body if you eat food or drink water containing it if you swim, bathe, or shower in contaminated water if you touch recently sprayed plants or soil if you touch contaminated soil near hazardous waste sites or if you breathe air that contains methyl parathion, such as near factories or recently sprayed farm fields (or in recent accounts of the illegal use of methyl parathion, if you breathe air or touch contaminated surfaces inside homes where methyl parathion has been used to kill insects). By any means of exposure, methyl parathion goes into your body quickly and gets into your blood. From your bloodstream, methyl parathion goes to your liver, brain, and other organs. Your liver changes some of methyl parathion to a more harmful chemical called methyl paraoxon. Both methyl parathion and methyl paraoxon can bind to enzymes of your nerves within minutes or hours. Your liver breaks down methyl parathion and methyl paraoxon into less harmful substances. These less harmful substances leave your body in urine within hours or days. For more information, see Chapter 3. 

Biomagnification along terrestrial food chains is principally due to bioaccumulation from food, the principal source of most pollutants (Walker 1990b). In a few instances, the major route of uptake may be from air, from contact with contaminated surfaces, or from drinking water. The bioaccumulation factor (BAF) of a chemical is given by the following equation ... 

Primary irritants cause inflammation. Inflammation is one of the body s defence mechanisms. It is the reaction of a tissue to harm which is insufficient to kill the tissue and is typified by constriction of the small vessels in the affected area, dilation of the blood vessels, increased permeability of the vessel walls, and migration of the white blood and other defensive cells to the invading harmful chemical. The aim is to concentrate water and protein in the affected area to dilute the effect and wash away the chemical. Production of new cells is speeded up and contaminated surface cells are shed. 

Madsen EL, CL Mann, SE Bilotta (1996a) Oxygen limitations and aging as explanations for the field persistence of naphthalene in coal tar-contaminated surface sediments Environ Toxicol Chem 15 1876-1882. 

Petroleum spillages can be removed from water surfaces more efficiently with the following detergent mixture [1692], which contains mainly oxyethyl-ate fatty Cio to C20 alcohols and additional oxyethylated fatty Cn to Cyj acids with an oxyethylene chain length of one to two units. It is used in the form of an aqueous 20% to 25% emulsion, which is sprayed onto a contaminated surface. 

The first draft (finished in 1993 and revised in 1995) describes a test method for determination of the bactericidal activity of a chemical disinfectant applied to a contaminated surface under laboratory conditions ... 

Decontamination None needed in the field wash contaminated surfaces with a 5% solution by weight of sodium hydroxide in 95%... 

Due to the low volatility of cyromazine and the use of water-soluble bags for packaging the Trigard formulation, the main routes of exposure were expected to be from direct contact with the product or spray mixture on contaminated surfaces. Previous experience with pesticides worker exposure studies indicated that exposure from vapors or spray mist would be a minor factor. This can easily be confirmed by the PHED or similar published sources however, the extent of exposure from inhaling the product as dust is less well known. This route of exposure was also assumed to be minor, particularly with the use of water-soluble bag packaging. Given the low mammalian toxicity of cyromazine, the operators did not wear respiratory protection. 

Four of the 15 operators had exceptional exposure compared to the other 11 which reveals improper use of protective gloves and/or handling contaminated surfaces with bare hands. The same four operators had high exposure on other areas and much lower safety factors which shows a clear link between poor work habits and higher exposure. The pattern of exposure confirms that direct contact with spray mixture on contaminated surfaces is the main route of exposure when using product in water-soluble bags. 

Automated equipment reduces exposure by eliminating handling of contaminated surfaces. 

Dermal exposure by direct contact with contaminated surfaces was the main route of exposure this could be greatly reduced by proper use and removal of nitrile gloves. 

Acrylonitrile is both readily volatile in air (0.13 atm at 23° C) (Mabey et al. 1982) and highly soluble in water (79,000 mg/L) (Klein et al. 1957). These characteristics dominate the behavior of acrylonitrile in the environment. While present in air, acrylonitrile has little tendency to adsorb to particulate matter (Cupitt 1980), so air transport of volatilized material is determined mainly by wind speed and direction. Similarly, acrylonitrile dissolved in water has only a low tendency to adsorb to suspended soils or sediments (Roy and Griffin 1985), so surface transport is determined by water flow parameters. Based on its relatively high water solubility, acrylonitrile is expected to be higly mobile in moist soils. In addition, acrylonitrile may penetrate into groundwater from surface spills or from contaminated surface water. The high vapor pressure indicates that evaporation from dry soil samples is expected to occur rapidly (EPA 1987). 

Velsicol Chemical Corporation maintained two injection wells at its plant near Marshall, Illinois, to dispose of caustic wastes from pesticide production as well as contaminated surface runoff. In September 1965, the company began to inject the wastes into Devonian dolomites of the Grand Tower Formation at a depth of about 2600 feet. The wells accepted about 6 million gallons of waste monthly. 

Earthworms, Lumbricus rubellus, Aporrectodea rosea Earthworms absent from plats with medium and high contamination. Surface casts of L. rubellus had 17.5 mg/kg DW in low contamination soils vs. 7.0 in controls for A. rosea. These values were 13.3 vs. 7.0 120... 

CW agents can be washed and rinsed away, dried up, sucked up by absorbent substances, or removed by heat treatment. Water, with or without additives of detergents, soda, soap, etc., can be used, as well as organic solvents such as fuel, paraffin and carburettor spirit. Emulsified solvents in water can be used to dissolve and wash-off CW agents from various contaminated surfaces. 

From 1949 to 1958, Nor-Acme Gold Mine piped 227,000 tonnes of refractory gold-bearing sulfide concentrate into a rock-walled impoundment (Richardson Ostry 1996, Salzsauler et al. 2005) in hope of finding a means to extract the gold. The ARS remained uncovered until 2000 when a cover was placed to inhibit sulfide oxidation and prevent further contaminated surface runoff. Arsenic is... 

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