“…The lipophilic para,para ‐DDT and ortho,para ‐DDT are extracted by a suitable solvent such as diethyl ether, and the aqueous phase containing the sulfonated haloaromatics was usually dumped into special landfills or, probably, directly into wastewater streams. The dominating residual compound, 4‐chlorobenzene sulfonic acid (4CBSA), consequently, is being found in sewage treatment plants, groundwater, marine estuaries (Kendall, 1989; Alonso et al ., 1999; 2002; Suter et al ., 1999; Loos et al ., 2000), and in the leachates of chemical waste deposits; in one case accounting for up to 69% of the total organic carbon of the effluent (Brown et al ., 1989; Kim et al ., 1990). 4CBSA itself has some commercial use; it is being found in applications of stains and its structure can be found in the acaricide chlorfenson (4‐chlorophenyl 4‐chlorobenzenesulfonate, Ovex ® ) from which it is being released through hydrolysis of the sulfate ester bond, and in anthelmintic and anti‐HIV drug preparations (thenium closylate).…”