One possible confounding factor, however, is that the children were not tested for lead exposure when they were toddlers.
然而一个可能的混淆的因素是孩子没有被测试是否在刚学走路时就处在污染环境中。
2
Another extra risk factor in organic production is the avoidance of fungicides, which can lead to the growth of moulds and increased risk of mycotoxins such as aflatoxin and ergot in crops.