Improving the Risk Assessment of Pesticides through the Integration of Human Biomonitoring and Food Monitoring Data: A Case Study for Chlorpyrifos

Abstract

The risk assessment of pesticide residues in food is a key priority in the area of food safety. Most jurisdictions have implemented pre-marketing authorization processes, which are supported by prospective risk assessments. These prospective assessments estimate the expected residue levels in food combining results from residue trials, resembling the pesticide use patterns, with food consumption patterns, according to internationally agreed procedures. In addition, jurisdictions such as the European Union (EU) have implemented large monitoring programs, measuring actual pesticide residue levels in food, and are supporting large-scale human biomonitoring programs for confirming the actual exposure levels and potential risk for consumers. The organophosphate insecticide chlorpyrifos offers an interesting case study, as in the last decade, its acceptable daily intake (ADI) has been reduced several times following risk assessments by the European Food Safety Authority (EFSA). This process has been linked to significant reductions in the use authorized in the EU, reducing consumers’ exposure progressively, until the final ban in 2020, accompanied by setting all EU maximum residue levels (MRL) in food at the default value of 0.01 mg/kg. We present a comparison of estimates of the consumer’s internal exposure to chlorpyrifos based on the urinary marker 3,5,6-trichloro-2-pyridinol (TCPy), using two sources of monitoring data: monitoring of the food chain from the EU program and biomonitoring of European citizens from the HB4EU project, supported by a literature search. Both methods confirmed a drastic reduction in exposure levels from 2016 onwards. The margin of exposure approach is then used for conducting retrospective risk assessments at different time points, considering the evolution of our understanding of chlorpyrifos toxicity, as well as of exposure levels in EU consumers following the regulatory decisions. Concerns are presented using a color code, and have been identified for almost all studies, particularly for the highest exposed group, but at different levels, reaching the maximum level, red code, for children in Cyprus and Israel. The assessment uncertainties are highlighted and integrated in the identification of levels of concern.

Applicability of Food Monitoring Data for Assessing Relative Exposure Contributions of Pyrethroids in Retrospective Human Biomonitoring Risk Estimations

“…While the common metabolites associated with the 3-phenoxybenzyl alcohol moiety facilitate screening assessments [ 19 ], the lack of unique urinary metabolites adds complexity for refining the risk, triggering our previous proposal for a tiered approach [ 9 ]. As dietary exposure is the most significant for the general population, the EU-wide information on pesticide residues in food annually reported by EFSA has been proposed by several authors as an information source for risk refinement [ 16 , 20 ]. The comprehensive European food consumption database [ 21 ] has not been implemented for pesticide risk assessment yet; the EFSA Model PRIMo [ 15 ] is based on national diets provided by EU member states; the overall representativeness of each diet for the European citizens has been questioned [ 20 ] and the worst-case was selected for proposing regulatory options.…”

“…The EFSA annual reports on food monitoring data have been previously used for comparing dietary estimations with real human biomonitoring data for pesticides such as chlorpyrifos with simple metabolic profiles [ 16 ]. Our results confirm their potential use for informing more complex situations.…”

“…The expected levels of urinary pyrethroid metabolites for each diet were estimated as described previously [ 16 ] using the molar urinary fractions for pyrethroids proposed by Tarazona et al [ 9 ]. Briefly, the urinary levels expected for each metabolite at any daily dietary exposure of the parent pesticide can be estimated according to the following equation: where Fue is the molar urinary fraction of the metabolite, and MWratio is the ratio between the molecular weights of the metabolite and the parent pesticide.…”

Biosensing Chlorpyrifos in Environmental Water Samples by a Newly Developed Carbon Nanoparticle-Based Indirect Lateral Flow Assay

“…A study, based on food monitoring and human biomonitoring, showed strong reductions of CHLP usage from 2016 onwards, which can be ascribed to regulations and awareness of the potentially harmful effects of CHLP [ 23 ]. In addition, the production of CHLP by Dow Chemical/Coverta was halted [ 9 ].…”

Editorial for the Special Issue on “Human Biomonitoring in Health Risk Assessment: Current Practices and Recommendations for the Future”

“…When no HBM data are available, for example, in the case of prospective assessments, the internal dose of a pesticide in human can be estimated by the expected residue levels in food. Tarrazona et al (2022) [ 13 ] compared consumers’ internal exposure to chlorpyrifos based on the urinary marker 3,5,6-trichloro-2-pyridinol (TCPy), using two sources of monitoring data: monitoring of the food chain from the EU program and biomonitoring of European citizens from the HBM4EU initiative, supported by a literature search. Both methods confirmed a drastic reduction in the exposure levels from 2016 onwards.…”