Another study headed by Swan found that men with low sperm counts living in a rural farming area of Missouri had elevated levels of herbicides (such as alachlor and atrazine) in their urine.

• 史万还有另一项研究，她在美国密苏里州的农村地区发现，精虫数目较少的男性，其尿液含有较多的除草剂，例如拉草和草脱净。