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Semen Quality Affected By Exposure to Pesticides
(Beyond Pesticides, September 17, 2003) In a study published in the April 2003 issue of Environmental Health Perspectives, researcher Shanna H. Swan associated rural living with reduced sperm quality. Now the University of Missouri-Columbia School of Medicine professor and her team of researchers have shown for the first time a correlation between non-persistent pesticide exposure and the same reduced sperm quality parameters. The researchers believe that the latest study, "Semen Quality in Relation to Biomarkers of Pesticide Exposure," published in the September 2003 issue of Environmental Health Perspectives, explains the decreased sperm quality in the rural men.

Dr. Swan selected men in whom all semen parameters (concentration, percentage sperm with normal morphology, and percentage motile sperm) were low for test subjects and men in whom all semen parameters were within normal limits for controls within Missouri and Minnesota and measured metabolites of eight current-use pesticides in urine samples provided at the time of semen collection.

Pesticide metabolite levels were elevated in Missouri cases, compared with controls, for the herbicides alachlor and atrazine and for the insecticide diazinon. Men from Missouri with high levels of alachlor were significantly more likely to have decreased sperm quality than were men with low levels of alachlor, as were men with atrazine levels higher than the limit of detection. The herbicides 2,4-D and metolachlor were also associated with poor semen quality in some analyses, whereas acetochlor levels were lower in men with reduced sperm quality than in controls.

No significant associations were seen for any pesticides within Minnesota, where levels of agricultural pesticides were low, or for the insect repellant DEET or the malathion metabolite malathion dicarboxylic acid.