1.2- Dibromo-3-chloropropane soils

Residues Determination of Dibromo-chloropropane in crops, soil, water" Shell Development Co., Biological Sciences Research Center, Modesto, CA, Method MMS-R-272-3, 1976. 

Our knowledge of effects on terrestrial species is largely derived from the use of methyl chloride, methyl bromide, chloroform, carbon tetrachloride, ethylene dichloride, ethylene dibromide, dibromo-chloropropane and dibromobutane as fumigants, for the control of pests of stored grain, and of soil nematodes [11, 40]. A typical fumigant dose is of the order of 50 mg/1, which is similar to the measured action levels against aquatic organisms shown in Table 9. 

Biological. Soil water cultures converted l,2-dibromo-3-chloropropane to 1-propanol, bromide, and chloride ions. Precursors to the alcohol formation include allyl chloride and allyl alcohol (Castro and Belser, 1968). 

Castro, C.E. and Belser, N.O. Biodehalogenation. Reductive dehalogenation of the biocides ethylene dibromide, l,2-dibromo-3-chloropropane, and 2,3-dibromobutane in soil, Environ. Sci. Technoi, 2(10) 779-783, 1968. 

Soil core data are available for only six of the pesticides discussed in this paper. The six pesticides are aldlcarb atrazlne 1,2-dibromo-3-chloropropane (DBCP) 1,2-dlchloropro-pane (DCP) 1,2-dlbromoethane (EDB) and slmazlne. Cores were always sampled at depths greater than one meter and the soil was characterized physically and chemically. The importance of soil core sampling in pesticide leaching assessments is presented in the Discussion section. 

Use of l,2-dibromo-3-chloropropane as a pesticide, soil fumigant and a nematocide resulted in the direct release of this compound to the environment. Its production and use as an intermediate in organic synthesis also may have resulted in its release to the environment through various waste streams. It has been detected at low levels in ambient and urban air, groundwater, drinking-water and soil samples (United States National Library of Medicine, 1997). 

Exposure to l,2-dibromo-3-chloropropane has occurred during its production and use as a pesticide, nematocide and soil fumigant however, production is believed to have ceased. It has been detected at low- levels in ambient air, water and soil. 

Two additional compounds containing 1,2-dihalo-ethyl groups are also nephrotoxicants. The nemato-cide and soil fumigant l,2-dibromo-3-chloropropane and the flame retardant tris(2,3-dibromopropyl)phos-phate both induce acute tubular necrosis. Although conjugation with glutathione may play a role in the toxicity induced by these agents, the mechanism responsible for the nephrotoxicity induced by these compounds is not known. 

While both industrial and agricultural chemicals have been found in California ground waters, pesticides injected beneath the soil surface to control nematodes are a particular concern. The nematicide 1,2-dibromo-3-chloropropane (DBCP), which was banned in California in 1977, is the most serious example of this problem in California (1-2). Figure 1 shows the increase between 1979 and 1984 in the number of wells found to contain measurable quantities of DBCP. As of April 1984, 2522 wells contained DBCP, with over half these wells (1455) having concentrations in excess of 1.0 part per billion, the current California "action level". 

DBCP (l,2-dibromo-3-chloropropane), a soil nematicide/ fumigant, was found in ground water and found to pose significant health risks. In 1979, all uses of DBCP in the continental U.S. were suspended (8) and the remaining use in pineapple fields in Hawaii was cancelled in 1985 (9). 

NEMAFENE (8003-19-8) see dichloropropene-dichloropropane mixture. NEMAGONE or NEMAGON SOIL FUMAGANT or NEMANAX or NEMAPAZ or NEMASET or NEMATOX (96-12-8) see l,2-dibromo-3-chloropropane. 

As with nucleophilic substitution reactions, rates of dehydrohalogenation reactions will be dependent on the strength of the C-X bond being broken in the elimination process. Accordingly, it is expected that the ease of elimination of X will follow the series Br>Cl>F. The relative reactivities of Br and Cl toward elimination is evident from the hydrolysis product studies of 1,2-dibromo-3-chloropropane (DBCP Burlinson et al., 1982). DBCP has been used widely in this country as a soil fumigant for nematode control and has been detected in groundwaters (Mason et al., 1981) and subsoils (Nelson, et al., 1981). Hydrolysis kinetic studies demonstrated that the hydrolysis of DBCP is first order both in DBCP and hydroxide ion concentration above pH 7. Below pH 7, hydrolysis occurs via neutral hydrolysis however, the base-catalyzed reaction will contribute to the overall rate of hydrolysis as low as pH 5. Product studies performed at pH 9 indicate that transformation of DBCP occurs initially by E2 elimination of HBr and HCl (Figure 2.4). 

Dibromo-3-chloropropane (DBCP) ( Nemagon ) and 1,2-dibromoethane are volatile nematocide formerly used to rid soil of these undesirable worms. Plants are remarkably tolerant to them but they are toxic to humans. 

Biological. Biodegradation is not expected to be significant in removing 1,2-dibromo-3-chloropropane. In aerobic soil columns, no degradation was observed after 25 days (Wilson et d., 1981a). 

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