Determinants of urinary concentrations of dialkyl phosphates among pregnant women in Canada — Results from the MIREC Study.

Sokoloff K, Fraser WD, Arbuckle TE, Fisher M, Gaudreau E, LeBlanc A, Morisset AS, Bouchard MF. Environment International. 2016 Sep;94:133-140. doi: 10.1016/j.envint.2016.05.015

Organophosphate (OP) pesticides are typically used in agriculture to protect crops from insects, and may be also used in residential and commercial households to fight pests. Several of these pesticides have been voluntarily discontinued or have had their residential uses severely restricted. Humans may be exposed to low levels of OPs either via diet (fruits and vegetables), or if they are living in or around areas where these pesticides have been applied. Usually OPs do not stay in the body for long. They are quickly broken down to OP residues and then excreted in the urine. In some studies, higher levels of OP residues measured in urine during pregnancy were associated with adverse mental development and attention problems in children.

The objective of this study was to examine the relationship between levels of OP pesticide residues in maternal urine and various factors that are potential sources of exposure or determinants of levels. Data and urine samples were collected from 1,884 MIREC participants. The OP residues were measured in 1st trimester urine samples and information on maternal age and education, household income, and diet was collected by questionnaire.

The results revealed that 93% of women had at least one OP residue detected in their urine. Women with a university degree, higher income, non-smokers or those with a normal pre-pregnancy body mass index (BMI = below 25 kg/m2) usually had higher levels of OP residues in their urine. Higher urinary levels were also associated with women reporting more intake of citrus fruits, apple juice, sweet peppers, tomatoes, beans and dry peas, soy and rice beverages, whole grain bread, white wine, and green and herbal teas. The results of this study may be useful to agencies responsible for regulating pesticides in their re-evaluation of OP and their uses.

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