4.1. CHEMICAL IDENTITY

When we refer to DDT, we are generally referring to p,p’-DDT, which was produced and used for its insecticidal properties. However, technical-grade DDT, the grade that was generally used as an insecticide, was composed of up to 14 chemical compounds, of which only 65–80% was the active ingredient, p,p’-DDT. The other components included 15–21% of the nearly inactive o,p’-DDT, up to 4% of p,p’-DDD, and up to 1.5% of 1-(p-chlorophenyl)-2,2,2-trichloroethanol (Metcalf 1995).

The chemical formulas, structures, and identification numbers for p,p’-DDT, p,p’-DDE, p,p’-DDD, o,p’-DDT, o,p’-DDE, and o,p’-DDD are listed in Table 4-1. The latter five compounds are either impurities or metabolites of technical DDT.

Table 4-1

Chemical Identity of p,p’- and o,p’-DDT, DDE, and DDD.

4.2. PHYSICAL AND CHEMICAL PROPERTIES

Technical DDT is a white amorphous powder that melts over the range of 80–94°C (Metcalf 1995). Physical and chemical properties of p,p’-DDT, p,p’-DDE, p,p’-DDD, o,p’-DDT, o,p’-DDE, and o,p’-DDD are listed in Table 4-2.

Table 4-2

Physical and Chemical Properties of p,p’- and o,p’-DDT, DDE, and DDD.