residues of different pesticides, ingestion of different food items containing residues
of one specific pesticide, or ingestion of several food items containing residues of
different pesticides. Other approaches can estimate cumulative risk, such as margin
of exposure (MoE), the ratio of no-observed-adverse-effect level (NOAEL) obtained
from animal toxicology studies to the predicted and estimated exposure dose, and
cumulative risk index (CRI), the reciprocal of the HI because both are based on
reference values [5, 32, 36].
Evans et al. [36] calculated cumulative risk HIs and individual risk HQs of
67 pesticides in 5-year cumulative data provided by the Joint FAO/WHO Meeting
on Pesticide Residues (JMPR) for 13 different regions (Global Environment Monitoring System – Food Contamination and Assessment Programme) [37]. Presence
of isomers was considered. Individual risk assessment showed an HQ larger than
1 twice only for chlorpyrifos-methyl. Cumulative risk assessment showed HIs larger
than 1 for all regions. Region B, comprising Africa, Europe, and Middle East,
showed a surprising HI larger than 10. Calculated HIs suggest a great contamination
risk and call for broader collection and more refined treatment of data. When HI
values exceed 1, HQ distributions can help in identifying the compounds with more
significance to the cumulative risk and how the risk assessment model can be
adjusted to incorporate those effects [36].
The European Food Safety Authority (EFSA) devised a methodology to classify
pesticides into cumulative assessment groups, or CAGs. The methodology rests on
the assumption that pesticides causing the same specific effects can produce cumulative toxicity – even if they do not have similar modes of action. CAGs are defined
according to pesticides’ chemical structure, toxicity mechanisms in mammals, and
common toxic effects [38]. Cumulative risk assessment is then defined from CAG
data based on hazard identification (effects specific to vulnerable populations and
effects from stressor interactions) for further determination of the dose-response
assessment (dose-response for sensitive populations, toxicological interactions, and
combined doses of multiple stressors) and exposure assessment (multiple exposure
routes and pathways, social, cultural, and economic factors that influence exposure)
concluding with risk characterization (uncertainties associated with combining risks
and qualitative factors affecting risk outcomes) [38]. The US Environmental Protection Agency (EPA) defined the CRA for five different classes of pesticides: organophosphates, N-methylcarbamates, s-triazines, chloroacetanilides, and pyrethrins/
pyrethroids. The most recent CRA regarding pyrethroids was published in 2011 and
includes a class of pyrethroids which trigger neurotoxicological effects via voltagegated sodium ion channel through the cell membrane. All pyrethroids were classified
under only one CAG, with deltamethrin as index compound (IC). The IC is selected
to model the associated risk and extrapolate the estimated exposure levels in the
population, thus decreasing errors and uncertainties in the risk assessment estimates.
Pyrethroids with toxic potential significantly lower than IC and those with no
detectable residues in monitoring were disregarded.
According to the EFSA, pesticides may cause toxic effects at multiple sites by a
single mode of action. Therefore, substances can be grouped in more than one CAG.
The effects considered for the establishment of reference values (ADI and ARfD) are
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T. M. Pizzolato and A. Dallegrave
of one specific pesticide, or ingestion of several food items containing residues of
different pesticides. Other approaches can estimate cumulative risk, such as margin
of exposure (MoE), the ratio of no-observed-adverse-effect level (NOAEL) obtained
from animal toxicology studies to the predicted and estimated exposure dose, and
cumulative risk index (CRI), the reciprocal of the HI because both are based on
reference values [5, 32, 36].
Evans et al. [36] calculated cumulative risk HIs and individual risk HQs of
67 pesticides in 5-year cumulative data provided by the Joint FAO/WHO Meeting
on Pesticide Residues (JMPR) for 13 different regions (Global Environment Monitoring System – Food Contamination and Assessment Programme) [37]. Presence
of isomers was considered. Individual risk assessment showed an HQ larger than
1 twice only for chlorpyrifos-methyl. Cumulative risk assessment showed HIs larger
than 1 for all regions. Region B, comprising Africa, Europe, and Middle East,
showed a surprising HI larger than 10. Calculated HIs suggest a great contamination
risk and call for broader collection and more refined treatment of data. When HI
values exceed 1, HQ distributions can help in identifying the compounds with more
significance to the cumulative risk and how the risk assessment model can be
adjusted to incorporate those effects [36].
The European Food Safety Authority (EFSA) devised a methodology to classify
pesticides into cumulative assessment groups, or CAGs. The methodology rests on
the assumption that pesticides causing the same specific effects can produce cumulative toxicity – even if they do not have similar modes of action. CAGs are defined
according to pesticides’ chemical structure, toxicity mechanisms in mammals, and
common toxic effects [38]. Cumulative risk assessment is then defined from CAG
data based on hazard identification (effects specific to vulnerable populations and
effects from stressor interactions) for further determination of the dose-response
assessment (dose-response for sensitive populations, toxicological interactions, and
combined doses of multiple stressors) and exposure assessment (multiple exposure
routes and pathways, social, cultural, and economic factors that influence exposure)
concluding with risk characterization (uncertainties associated with combining risks
and qualitative factors affecting risk outcomes) [38]. The US Environmental Protection Agency (EPA) defined the CRA for five different classes of pesticides: organophosphates, N-methylcarbamates, s-triazines, chloroacetanilides, and pyrethrins/
pyrethroids. The most recent CRA regarding pyrethroids was published in 2011 and
includes a class of pyrethroids which trigger neurotoxicological effects via voltagegated sodium ion channel through the cell membrane. All pyrethroids were classified
under only one CAG, with deltamethrin as index compound (IC). The IC is selected
to model the associated risk and extrapolate the estimated exposure levels in the
population, thus decreasing errors and uncertainties in the risk assessment estimates.
Pyrethroids with toxic potential significantly lower than IC and those with no
detectable residues in monitoring were disregarded.
According to the EFSA, pesticides may cause toxic effects at multiple sites by a
single mode of action. Therefore, substances can be grouped in more than one CAG.
The effects considered for the establishment of reference values (ADI and ARfD) are
254
T. M. Pizzolato and A. Dallegrave