2,4-Dichlorophenoxyacetic acid residues in semen of Ontario farmers

Although paternal exposures to environmental toxicants probably play a role in adverse pregnancy outcomes, few data are available on the extent of this exposure. One semen and two 24-h urine samples were collected from 97 Ontario farmers who had recently used the phenoxy herbicides 2,4-D (2,4-dichlorophenoxyacetic acid) and/or MCPA ([4-chloro-2-methylphenoxy] acetic acid). Both samples were analyzed for 2,4-D using an immunoassay-based technique. Approximately 50% of the semen samples had detectable levels of 2,4-D (greater than or equal to 5.0 ppb (ng/mL)). Semen levels of 2,4-D were correlated more closely with the second of the two urine samples. Although several studies have measured 2,4-D in the urine of applicators, this study is the first to attempt to measure 2,4-D levels in semen. As these pesticides can be excreted in the semen, they could be toxic to sperm cells and be transported to the woman and developing embryo/fetus. Further research is needed to understand how pesticide handling practices can affect semen pesticide residues and the relationship between the levels observed and reproductive health. (C) 1999 Elsevier Science Inc. All rights reserved.