ABSTRACT
Many of the most widely used pesticides are halogenated aromatic compounds. The majority of these compounds are chlorinated, but brominated and fluorinated aromatic pesticides are also in use [1-3]. These can be classified into various chemical groups, such as phenols, phenoxy alkanoic acids, benzoic acid derivatives, acetanilides, and amides. Some notable halogenated aromatic pesticides currently in widespread use include 2,4-dichlorophenoxyacetic acid (2,4-D), alachlor (2-chloro-A^-(2,6-diethylphenyl)-N-(methoxymethyl) acetamide), mecoprop [(RS)- 2-(4-chloro-2 - methylohenoxy)propanoic acid], bromoxynil (3,5-dibromo-hydroxybenzonitrile), chloramben (3-amino-2,5-dichlorobenzoic acid), MCPA [(4-chloro-2-methyl)phenoxyacetic acid], propanil (7V-(3,4-dichlorophenyl)propanamide), chlorothalonil (2,4,5,6-tetrachloro-1,3-benzene-dicarbonitrile), and the chlorinated N-heterocyclic triazines, such as atra-zine (2-chloro-4-ethylamino-6-isopropylamino-l,3,5-triazine) and simazine (2-chloro-4,6-bis(ethylamino)-s-triazine) (see structures in Fig. 1).A variety of halogenated aromatic compounds are also produced naturally by some fungi and marine worms, sometimes in considerable quantities [4-6]. * Current affiliation: Darling Marine Center, University of Maine, Walpole, Maine.
