Chlorinated hydrocarbon concentrations

Bishop CA, Rouse JD. 2000. Chlorinated hydrocarbon concentrations in plasma of Lake Erie water snake Nerodia sipedon insularum) and northern water snake (Nemdia sipedon sipedon) from the Great Lakes Basin in 1998. Arch Environ Contam Toxicol 39 500-505. 

Fowler, S.W., 1990. Critical review of selected heavy metal and chlorinated hydrocarbon concentrations in the marine environment. Mar. Environ. Res. 29, 1-64. 

Fowler SW (1990) Critical review of selected heavy metal and chlorinated hydrocarbon concentrations in the marine environment. Mar Environ Res 29(l) l-64 Gauthier TD, Seitz WR, Grant CL (1987) Effects of structural and compositional variations of dissolved humic materials on pyrene Koc value. Environ Sci Technol 21(3) 243-248... 

EVA copolymers are resistant to acids (except oxidizers), bases, detergents, oils, fats, alcohols, ketones, and aliphatic hydrocarbons. They are not resistant to oxidizing acids, aromatic and chlorinated hydrocarbons, concentrated mineral acids, ketones, and amines. 

In general, amorphous polyamides are somewhat less resistant and more prone to stress-cracking than semi-crystalline polyamides, Table 5.93. Amorphous, partially aromatic polyamides are resistant to gasoline, benzene, paraffin oil, aliphatic and aromatic hydrocarbons, ketones, dilute hydrochloric acid, dilute sulfuric acid, aqueous salt solutions, dilute caustic soda, and formaldehyde. They are not resistant to ethanol, propanol, butyl alcohol, ethylene glycol, propylene glycol, chlorinated hydrocarbons, concentrated mineral acid, and formic acid. 

The FDA has pubhshed methods for the deterrnination of residual solvents in spice extracts such as oleoresins and has limited the concentrations of those specific solvents that are permitted. Chlorinated hydrocarbons and benzene have been almost completely removed from use as extracting solvents in the United States their use continues overseas where toxicity regulations are less stringent. The presence of pesticides or herbicides in spices is rigidly controHed by the FDA. 

Both CI2 and HCl have been shown to chlorinate hydrocarbons on fly ash particles. Pilot-scale data involving the injection of fly ash from municipal waste combustion (33) show that intermediate oxygen concentrations (4—7%) produce the highest levels of PCDD and PCDF. These data also show significant reductions in PCDD and PCDF emissions with the upstream injection of Ca(OH)2 at about 800°C. 

Pesticides. Chlorinated hydrocarbon pesticides (qv) are often found in feed or water consumed by cows (19,20) subsequently, they may appear in the milk, where they are not permitted. Tests for pesticides are seldom carried out in the dairy plant, but are most often done in regulatory or private specialized laboratories. Examining milk for insecticide residues involves extraction of fat, because the insecticide is contained in the fat, partitioning with acetonitrile, cleanup (FlorisH [26686-77-1] column) and concentration, saponification if necessary, and determination by means of paper, thin-layer, microcoulometric gas, or electron capture gas chromatography (see Trace and residue analysis). 

Unplasticized polyvinyl chlorides (type I) have excellent resistance to oxidizing acids other than concentrated and to most nonoxidizing acids. Resistance is good to weak and strong alkahne materials. Resistance to chlorinated hydrocarbons is not good. Polyvinyhdene chloride, known as Saran, has good resistance to chlorinated hydrocarbons. 

Several other changes that are supposed to slow down the reaction can cause runaway. In the case of ethylene oxidation, chlorinated hydrocarbons are used as inhibitors. These slow down both the total and the epoxidation, although the latter somewhat less. When the reaction is running too high and the inhibitor feed is suddenly increased in an attempt to control it, a runaway may occur. The reason is similar to that for the feed temperature cut situation. Here the inhibitor that is in the ppm region reacts with the front of the catalytic bed and slowly moves down stream. The unconverted reactants reach the hotter zone before the increased inhibitor concentration does. 

The fluids have reasonably good chemical resistance but are attacked by concentrated mineral acids and alkalis. They are soluble in aliphatic, aromatic and chlorinated hydrocarbons, which is to be expected from the low solubility parameter of 14.9 MPa. They are insoluble in solvents of higher solubility parameter such as acetone, ethylene glycol and water. They are themselves very poor solvents. Some physical properties of the dimethylsilicone fluids are summarised in Table 29.2. 

In the selection of control equipment, the most important waste-gas characteristics are volumetric flow rate, concentration and composition of organic compounds in the waste-gas, waste-gas temperature and humidity, and rbe content of particulate matter, chlorinated hydrocarbons, and toxic pollutants. Other factors influencing the equipment selection are the required removal efficiency, recovery requirements, investment and operating costs, ease of installation, and considerations of operation and maintenance. The selection of a suitable control method is based on the fundamental selection criteria presented as well as the special characteristics of the project. 

The austenitic irons are superior to ordinary cast iron in their resistance to corrosion by a wide range of concentrations of hydrochloric acid at room temperature (Table 3.50). However, for practical uses where such factors as velocity, aeration and elevated temperatures have to be considered, the austenitic irons are mostly used in environments where the hydrochloric acid concentration is less than 0- 5%. Such environments occur in process streams encountered in the production and handling of chlorinated hydrocarbons, organic chlorides and chlorinated rubbers. 

The silica gel surface is extremely polar and, as a result, must often be deactivated with a polar solvent such as ethyl acetate, propanol or even methanol. The bulk solvent is usually an n-alkane such as n-heptane and the moderators (the name given to the deactivating agents) are usually added at concentrations ranging from 0.5 to 5% v/v. Silica gel is very effective for separating polarizable materials such as the aromatic hydrocarbons, nitro hydrocarbons (aliphatic and aromatic), aliphatic ethers, aromatic esters, etc. When separating polarizable substances as opposed to substances with permanent dipoles, mixtures of an aliphatic hydrocarbon with a chlorinated hydrocarbon such as chlorobutane or methylene dichloride are often used as the mobile... 

Sediment pollution. The concentrations of pollutants in the dated sediment cores have been determined in our laboratory by atomic absorption spectrophotometry (AAS). Donazzolo et al. (15) and Pavoni et al. (16) reported mainly heavy metal concentrations. Marcomini et al. (17) and Pavoni et al. (18) discussed the concentration profiles of organic pollutants such as chlorinated hydrocarbons and polycyclic aromatic hydrocarbons. 

Wastewaters containing chlorinated hydrocarbons (CHCs) are very toxic for aquatic system even at concentrations of ppm levels [1] thus, appropriate treatment technologies are required for processing them to non-toxic or more biologically amenable intermediates. Catalytic wet oxidation can offer an alternative approach to remove a variety of such toxic organic materials in wet streams. Numerous supported catalysts have been applied for the removal of aqueous organic wastes via heterogeneous wet catalysis [1,2]. 

The reaction of volatile chlorinated hydrocarbons with hydroxyl radicals is temperature dependent and thus varies with the seasons, although such variation in the atmospheric concentration of trichloroethylene may be minimal because of its brief residence time (EPA 1985c). The degradation products of this reaction include phosgene, dichloroacetyl chloride, and formyl chloride (Atkinson 1985 Gay et al. 1976 Kirchner et al. 1990). Reaction of trichloroethylene with ozone in the atmosphere is too slow to be an effective agent in trichloroethylene removal (Atkinson and Carter 1984). 

Data gathered from several sites near Niigata, Japan, between April 1989 and March 1992 showed elevated levels of trichloroethylene and other volatile chlorinated hydrocarbons in the winter (Kawata and Fujieda 1993). A rural site in this study had armual mean concentrations between 0.17 and 0.32 ppb, while four industrial sites had mean concentrations between 0.029 and 4.8 ppb. The average trichloroethylene level detected in samples collected from ambient air in the Norwegian Arctic between 1982 and 1983 was 0.007 ppb (Hov et al. 1984). Average concentrations of trichloroethylene in Alaskan Arctic haze between 1980 and 1982 were 0.036 ppb in winter and 0.007 ppb in summer (Khalil and Rasmussen 1983). 

Becker PR. 2000. Concentration of chlorinated hydrocarbons and heavy metals in Alaska arctic marine mammals. Mar PoUut Bull 40 819-829. 

Acetone Acetylene Alkali and alkaline earth metals, e.g. sodium, potassium, lithium, magnesium, calcium, powdered aluminium Anhydrous ammonia Concentrated nitric and sulphuric acid mixtures Chlorine, bromine, copper, silver, flourine or mercury Carbon dioxide, carbon tetrachloride, or other chlorinated hydrocarbons. (Also prohibit, water, foam and dry chemical on fires involving these metals - dry sand should be available.) Mercury, chlorine, calcium hypochlorite, iodine, bromine or hydrogen fluoride... 

This technique has been applied to the concentration of organochlorine and organophosphorus insecticide [7,8] and various ethers, glycols amines, nitriles, hydrocarbons, and chlorinated hydrocarbons. Although this work was concerned with drinking water, it is a useful technique which may have application in seawater analysis. Cellulose acetate [9], ethyl cellulose acetate [6], and crosslinked polyethyleneinine [8] have been used as semi-permeable membranes. 

Picer and Picer [357] evaluated the application ofXAD-2, XAD-4, and Tenax macroreticular resins for concentrations of chlorinated insecticides and polychlorinated biphenyls in seawater prior to analysis by electron capture gas chromatography. The solvents that were used eluted not only the chlorinated hydrocarbons of interest but also other electron capture sensitive materials, so that eluates had to be purified. The eluates from the Tenax column were combined and the non-polar phase was separated from the polar phase in a glass separating funnel. Then the polar phase was extracted twice with n-pentane. The -pentane extract was dried over anhydrous sodium sulfate, concentrated to 1 ml and cleaned on an alumina column using a modification of the method described by Holden and Marsden. The eluates were placed on a silica gel column for the separation of PCBs from DDT, its metabolites, and dieldrin using a procedure described by Snyder and Reinert [359] and Picer and Abel [360]. 

Herrmann, R. and D. Hubner. 1984. Concentrations of micropollutants (PAH, chlorinated hydrocarbons and trace metals) in the moss Hypnum cupressiforme in and around a small industrial town in southern Finland. Ann. Hot. Fennici 21 337-342. 

Hi-Chloroff A thermal (non-catalytic) process for removing chlorine from chlorinated hydrocarbon wastes containing either low or high concentrations of chlorine. Developed by Kinetics Technology International. See also Chloroff. 

Aerobic degradation has been shown to be most effective in reducing the concentration of aliphatic and aromatic hydrocarbon fuel compounds. Anaerobic reactions are more effective in degrading chlorinated hydrocarbons and long-chain animal fats and oils. Detailed study is necessary to determine the most-effective procedure for a specific site. 

Organophosphates (Fig. 10, Table 3) are more toxic than chlorinated hydrocarbons, in particular to humans,but they exhibit lower persistence in soils and do not seem to accumulate in soil fauna or concentrate in birds and fish [74]. This behavior is also related to an enhanced water solubility and lower vapor pressure of organophosphates. Malathion and Parathion (Fig. 10, Table 3) insecticides are known to be chemically hydrolyzed and biodegraded by micro-... 

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