Biomonitoring Development Focus Area

In the February 2017 review of neonicotinoids by Cimino et al., published in the Journal, Environmental Health Perspectives (1), the researchers noted that the limited number of human studies published all suffered from the lack of a validated biomarker for neonicotinoid exposure and that a validated biomarker “would enable more accurate exposure assessment, greater understanding of metabolite production, greater understanding of absorption and elimination variability, and improved sensitivity testing to rule out false-positive results” as well as greatly assist future neonicotinoid human health investigations (1).

The lack of validated biomarkers of exposure represents a major obstacle for studies investigating exposures and adverse health effects of neonicotinoids in humans (1). Detection frequencies of the parent insecticides, such as imidacloprid, in urine appear to be high based on two studies of Chinese and Japanese subjects (2, 3).  These observations suggest that the parent compounds may be possible biomarkers of exposure. In addition, human neonicotinoid metabolites, for example 6-chloronicotinic acid and 2-chloro-1,3-thiazole-5-carboxylic acid (2CTCA), may be biomarkers of exposure. However, these metabolites are not specific for a particular insecticide (3).

The Iowa Neonicotinoid Collaborative is working to establish the analytical methodology to measure the parent neonicotinoids and the respective metabolites in human urine samples and to assess their suitability as biomarkers of exposure.  Plans are underway to collect urine samples from individuals at approximately 60 farms in Iowa who use well water as their primary source of drinking water and use neonicotinoids as a seed treatment on corn and/or soybeans.

Well Water Survey

Neonicotinoid insecticides have high water solubility and long half-lives in soil and water (4-8) and can potentially contaminate well water sources through different routes including surface runoff leaching into groundwater (9-14). Despite the widespread and intense use of neonicotinoids in Iowa over the past 10 to 20 years, Kolpin and Klarich (Collaborative members) and colleagues published the results of the first surveys on neonicotinoid concentrations in surface waters in Iowa in 2014 (15).  The researchers detected clothianidin, thiamethoxam, and imidacloprid in a substantial proportion of the samples collected. Research findings performed by Klarich, Kolpin and others in 2017 also documented that neonicotinoids can persist through water treatment processes and can be present in finished tap water (16). While Kolpin and Klarich performed some limited exploratory testing of neonicotinoids in municipal groundwater supplies in Iowa, published reports of neonicotinoid measurements in either municipal or private wells in Iowa or elsewhere in the U.S. are lacking.

The Collaborative aims to gain a better understanding of potential neonicotinoid exposure from ground water sources by sampling the well water of Iowa farmers, and their families, who drink well water and live in an “at risk” area, based on geology, for ground water contamination.  The Collaborative anticipates that alluvial wells and wells located in karst areas are particularly vulnerable to neonicotinoid contamination. As of January 2018, the Collaborative has sampled close to 400 wells from across Iowa.  The findings from these analyses will be reported in the near future.

References

1. Cimino AM, Boyles AL, Thayer KA, Perry MJ. Effects of Neonicotinoid Pesticide Exposure on Human Health: A Systematic Review. Environ Health Perspect. 2017;125(2):155-62.
2. Wang L, Liu T, Liu F, Zhang J, Wu Y, Sun H. Occurrence and Profile Characteristics of the Pesticide Imidacloprid, Preservative Parabens, and Their Metabolites in Human Urine from Rural and Urban China. Environ Sci Technol. 2015;49(24):14633-40.
3. Ueyama J, Nomura H, Kondo T, Saito I, Ito Y, Osaka A, et al. Biological Monitoring Method for Urinary Neonicotinoid Insecticides Using LC-MS/MS and Its Application to Japanese Adults. J Occup Health. 2014;56(6):461-8.
4. Kegley SE HB, Orme S, Choi AH. PAN Pesticide Database North America (Oakland, CA): Pesticide Action Network; 2016, Available from pesticideinfo.org.
5. Canadian Council of Ministers of the Environment (CCME), Canadian Water Quality Guidelines: Imidacloprid. Scientific Supporting Document. PN 1388, Winnipeg, Manitoba, 2007.
6. Authority EFS. Conclusion on the peer review of the pesticide risk assessment for bees for the active substance imidacloprid. EFSA Journal. 2013;11(1):3068 [55 pp].
7. Evans JD, Saegerman C, Mullin C, Haubruge E, Nguyen BK, Frazier M, et al. Colony collapse disorder: a descriptive study. PloS one. 2009;4(8):e6481.
8. Morrissey Ca MP, Devries JH, Sanchez-Bayo F, Liess M, Cavallaro MC, Liber K. Neonicotinoid contamination of global surface waters and associated risk to aquatic invertebrates: a review. Environment International. 2015.
9. Main AR HJ, Peru KM, Michel NL, Cessna AJ, Morrissey CA. Widespread use and frequent detection of neonicotinoid insecticides in wetlands of Canada’s Prairie Pothole Region. PLoS One. 2014;9(6): e101400
10. Lamers M AM, La N, Nguyen VV, Streck T. Pesticide pollution in surface- and groundwater by paddy rice cultivation: a case study from northern Vietnam. CLEAN – Soil, Air, Water. 2011;39(4):356-61.
11. Pest Management Regulatory Agency (PMRA), Imidacloprid: Regulatory Note – REG 2011-11. Health Canada, editor, 2001.  Available at: http://publications.gc.ca/collections/Collection/H113-7-2001-11E.pdf.
12. Krupke CH HG, Eitzer BD, Andino G, Given K. Multiple routes of pesticide exposure for honey bees living near agricultural fields. PLoS One. 2012;7(1):e29268.
13. Nuyttens D DW, Verboven P, Foque D. Pesticide-laden dust emission and drift from treated seeds during seed drilling: a review. Pest Management Science. 2013;69(5):564-75.
14. Kreutzweiser DP GK, Chartrand DT, Scarr TA, Thompson DG. Are leaves that fall from imidaclopridtreated maple trees to control Asian longhorned beetles toxic to non-target decomposer organisms? 2008;37(2):639-46.
15. Hladik ML, Kolpin DW, Kuivila KM. Widespread occurrence of neonicotinoid insecticides in streams in a high corn and soybean producing region, USA. Environmental Pollution. 2014;193:189-96.
16. Klarich KL, Pflug NC, DeWald EM, Hladik ML, Kolpin DW, Cwiertny DM, Gregory H. LeFevre. Occurrence of neonicotinoid insecticides in finished drinking water and fate during drinking water treatment. ES&T Letters. 2017;4 (5):168–173.
17. Center for Health Effects of Environmental Contamination, Iowa . Iowa Statewide Rural Well Water Survey Phase 2 (SWRL2), Results and Analysis. 2009.  Available at: https://cheec.uiowa.edu/research/iowa-statewide-rural-well-water-survey-phase-2-swrl2