DBCP

Some employees making a soil fumigant (DBCP) became... 

Williams RT, Ziegenfuss PS, Marks PJ. 1989. Installation restoration program environmental technology department. Biodegradation of DIMP, dieldrin, isodrin, DBCP, and PCPMSO in the RMA soils. West Chester, PA Roy F. Weston, Inc. NTIS No. AD-A245-852. 

Results of volatilization and leaching estimations are reported for six pesticides that span a wide range of the physical/chemical properties that affect fate at the soil/air interface. The pesticides are Mirex, toxaphene, methoxychlor, lindane, malathion, and dibromochloropropane (DBCP). These particular pesticides were chosen for discussion here because they illustrate the methods for assessing the fate of organics at the... 

In Table II, we use DBCP to illustrate how soil properties and conditions can affect diffusion half-lives. Increasing the... 

Table II. Volatilization Half-Lives of DBCP Mixed Into 10 cm of Several Kinds of Soils (day)...

Table III illustrates the impact of adsorption on the leaching of organic chemicals in the soil. A water input of 305 cm was used, which is equivalent to a full year of precipitation in the eastern United States. In a soil with a field capacity of 30%, the water would penetrate 1017 cm. Mirex with a very large Kqc is practically immobile after a full year of precipitation, it is still on the surface. It is likely that any compound adsorbed this strongly would be carried off the land surface by soil erosion instead of being leached into the soil. In contrast, DBCP, which is very weakly adsorbed, penetrates the soil profile almost as far as the water does.

For each of the model compounds, some material will have leached deeper Into the soil than Is shown in the table. The model calculates only the position of maximum concentration. For a compound like DBCP, which has a very weak adsorption interaction with the soil, the concentration profile will be spread out. DBCP would probably be found at low concentrations at the 1017 cm level. For the strongly adsorbed compounds, such as toxaphene and methoxychlor, the concentration peak will be narrow, and the depth of maximum concentration is the depth where most of the material is. 

Table IV uses DBCP to illustrate the effect of soil organic carbon concentration on leaching mobility. In the very low organic carbon soil, there is almost no adsorption for the compound and the leaching model breaks down because it predicts penetration depths greater than the water penetration. In these cases the prediction is adjusted to show compound and water penetration depths as the same.

Volatilization and leaching interact with each other and other fate processes. Two of the pesticides, DBCP and lindane, are discussed in some detail to illustrate some of the interactions. The other four are discussed only briefly. 

DBCP. The predictions suggest that DBCP is volatile and diffuses rapidly into the atmosphere and that it is also readily leached into the soil profile. In the model soil, its volatilization half-life was only 1.2 days when it was assumed to be evenly distributed into the top 10 cm of soil. However, DBCP could be leached as much as 50 cm deep by only 25 cm of water, and at this depth diffusion to the surface would be slow. From the literature study of transformation processes, we found no clear evidence for rapid oxidation or hydrolysis. Photolysis would not occur below the soil surface. No useable data for estimating biodegradation rates were found although Castro and Belser (28) showed that biodegradation did occur. The rate was assumed to be slow because all halogenated hydrocarbons degrade slowly. DBCP was therefore assumed to be persistent. 

The predicted fate of DBCP depends on the amount of water that enters the soil after it has been applied. With very little... 

For the determination of 1,2-dibromoethane (EDB) and l,2-dibromo-3-chloropro-pane (DBCP) in water by hexane microextraction and GC... 

Wong 0, Brocker W, Davis HV, et al. 1984. Mortality of workers potentially exposed to organic and inorganic brominated chemicals, DBCP, TRIS, PBB and DDT. Br J Ind Med 41 15-24. 

Dibromochloropropane (DBCP) investigated for causes leading to sterility now banned. 

MacFarland RT, Gandolfi AJ, Sipes IG. 1984. Extra hepatic reduced GSH-dependent metabolism of 1,2-dibromoethane and 1,2-dibromo-3-chloropropane (DBCP) in the rat and mouse. Drug Chem Toxicol 7 213- 227. 

Teramoto S, Saito R, Aoyama H, et al. 1980. Dominant lethal mutation induced in male rats by 1 2 Dibromo-3-chloro propane (DBCP). Mutat Res 77 71-78. 

The reproductive systems of both males and females can be harmed by particular chemicals. In males certain chemicals cause the testes to atrophy and reduce or eliminate their capacity to produce sperm. Particularly striking in this regard is a now banned but once widely used pesticide called DBCP, residues of which persist in ground water supplies in a few regions of the country. Its pronounced impact on spermatogenesis is readily detectable in experimental animals and, unfortunately, has also been observed in some men once occupation-ally exposed to large amounts. The heavy metal cadmium is another substance effective at reducing sperm production. 

Biggar, J.W., Nielson, D.R., and Tillotson, W.R. Movement of DBCP in laboratory soil columns and field soils to groundwater. Environ. Geol, 5(3) 127-131, 1984. 

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