Pesticide illness among flight attendants due to aircraft disinsection

Aircraft disinsection: what is the usefulness as a public health measure?

RATIONALE FOR REVIEW

Insecticide treatments in aircraft (termed 'aircraft disinsection') aim to support the containment of potentially disease-carrying vector insects. The introduction of non-endemic mosquito species is of concern as some mosquitoes can act as vectors of many serious human diseases. Expansion of vectors to previously non-endemic regions, extended flight networks and mosquito resistance to insecticides pose challenges to contemporary vector-control approaches. Despite established efficacy of aircraft disinsection in trials, there is increasing concern over its effectiveness and feasibility in flight operations, and its usefulness as a public health measure.

KEY FINDINGS

We explored the literature on disinsection through a narrative approach to obtain a pragmatic assessment of existing and future implementation challenges. We describe the shortcomings that hinder evaluation of the success of aircraft disinsection. These shortcomings include operational constraints that may impact effective treatment outcomes, lack of longitudinal data on pesticide exposure scenarios, lack of compliance mechanisms, pesticide resistance in mosquitoes, and limited evidence of the extent and type of mosquito species potentially transported via aircraft.

CONCLUSIONS AND RECOMMENDATIONS

Concerns about the introduction of non-endemic mosquito vectors reinforce the need for effective preventive measures. Import of disease vectors is likely to occur in the future under changing environmental and operational conditions. Optimal impact from disinsection requires appropriate deployment, commitment and use. The current system of evaluation is inadequate for producing the evidence needed for informed policy decisions. While utilizing the results of research into environmentally sustainable vector-control methods for use in aircraft, future approaches to aircraft disinsection require improved evidence of anticipated benefits and harms, reliable monitoring data on insecticide resistance, and must be supported by strong vector control at airports.

Nontransient third-degree heart block and persistent respiratory findings as sequelae of acute occupational exposure to pyrethroids insecticide

We present the case of a worker with occupational exposure to a pyrethroid insecticide who acutely developed nontransient third-degree heart block. In 2000, a 57-year-old male truck driver on his delivery route was accidentally exposed to pyrethroid insecticide being sprayed for West Nile virus containment. Both the driver and his vehicle were coated with the spray. The exposure was prolonged because he did not change his clothes until after his shift ended and he used the same contaminated truck for a week. Within days, he presented with a third-degree heart block, for which he was emergently treated, and a pacemaker was placed. He had no past history of arrhythmias. In the weeks thereafter, he also developed reactive airway dysfunction syndrome (RADS). In the second decade following the exposure, the patient replaced his pacemaker, confirming the permanent nature of his heart block. In addition to the persistence of his exposure-related RADS, he developed restrictive lung disease and was diagnosed with pulmonary interstitial fibrosis in the absence of established risk factors. The patient died in October 2019 from respiratory illness. Most previous reports of pyrethroid-related disorders are limited to acute exposures, in which transient symptoms predominate. To our knowledge, this is the first report of an exposed worker experiencing permanent third-degree heart block, as well as persistent respiratory findings, as possible short- and long-term sequelae of pyrethroid exposure.

The safety and applicability of synthetic pyrethroid insecticides for aircraft disinsection: A systematic review

BACKGROUND

Air travel contributes to the global spread of vectors and vector-borne infections. Although WHO provides guidance on methods for disinsection of aircraft, there is currently no harmonized or standardized decision-making process to decide when disinsection of an aircraft should be conducted. It is however compulsory for flights arriving in certain countries. Concerns have been expressed about the usefulness of disinsection for preventing the international spread of vectors and vector-borne diseases via air travel and possible toxicity for passengers and flight crew.

METHODS

We performed a systematic literature review using the databases PubMed, Embase, Medline, Scopus and CINAHL to evaluate all research findings about the applicability and safety of chemical-based, aircraft disinsection. Official reports from the WHO were also screened. This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and meta-analysis (PRISMA) statement. The literature search strategy included "disinsection, airplane/plane/aviation/aircraft" and several other search items including d-phenothrin, permethrin, insecticide. Papers in English, French and German were reviewed. Reports of adverse events attributed to the disinsection of aircraft were also searched. AMP and PS screened all papers of relevance and agreed on a final selection.

RESULTS

Our search resulted in 440 papers of possible relevance. After screening, we included a total of 25 papers in this systematic review. Ten papers reported possible human toxicity and 17 papers addressed the applicability of disinsection and 2 papers addressed both topics. Chemical disinsection at recommended insecticide concentrations was found to be highly effective against a broad range of arthropods. Three papers reported passenger or crew illness possibly associated with insecticide spraying in passenger cabins - one describing a single passenger, the other two papers describing occupational illness of 12 and 33 aircrew members respectively, possibly due to aircraft disinsection. Another paper evaluating exposure of flight attendants to permethrin found higher levels of urinary metabolites in those working in planes that had recently been sprayed but this could not be linked to adverse health outcomes.

CONCLUSION

Our analysis confirmed that disease vectors are carried on international flights and can pose a threat particularly to island populations and certain airport hub areas. Disinsection with permethrin or d-phenothrin was shown to be highly effective against vectors. Despite several hundred million passenger and crew exposures to chemical disinsection, very few proven cases of toxicity have been reported. There is limited evidence linking exposure to insecticide spraying with negative health impact.

Digital Delivery of Meditative Movement Training Improved Health of Cigarette-Smoke-Exposed Subjects

Many FA who flew prior to the ban on smoking in commercial aircraft exhibit an unusual pattern of long-term pulmonary dysfunction. This randomized controlled study tested the hypothesis that digitally delivered meditative movement (MM) training improves chronic obstructive pulmonary disease (COPD)-related symptoms in flight attendants (FA) who were exposed to second-hand cigarette smoke (SHCS) while flying. Phase I of this two-phase clinical trial was a single-arm non-randomized pilot study that developed and tested methods for MM intervention; we now report on Phase II, a randomized controlled trial comparing MM to a control group of similar FA receiving health education (HE) videos. Primary outcomes were the 6-min walk test and blood levels of high sensitivity C-reactive protein (hs-CRP). Pulmonary, cardiovascular, autonomic and affective measures were also taken. There were significant improvements in the 6-min walk test, the Multidimensional Assessment of Interoceptive Awareness (MAIA) score, and the COPD Assessment Test. Non-significant trends were observed for increased dehydroepiandrosterone sulfate (DHEAS) levels, decreased anxiety scores and reduced blood hs-CRP levels, and increased peak expiratory flow (PEF). In a Survey Monkey questionnaire, 81% of participants who completed pre and post-testing expressed mild to strong positive opinions of the study contents, delivery, or impact, while 16% expressed mild negative opinions. Over the course of the year including the study, participant adoption of the MM practices showed a significant and moderately large correlation with overall health improvement; Pearson's R = 0.62, p < 0.005. These results support the hypothesized benefits of video-based MM training for this population. No adverse effects were reported.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT02612389

Pesticide Application and Khat Chewing as Predictors of the Neurological Health Outcomes among Pesticide Applicators in a Vector Control Unit, Saudi Arabia

Background:

Pesticide applicators are at risk of developing neurological symptoms and neurobehavioral deficits. This risk may increase if the applicator chews stimulant plants like khat.

Objective:

To examine the sociodemographic and exposure determinants of neurological symptoms presentation, neurobehavioral performance, and cholinesterase activity among pesticide applicators in a vector control unit, Saudi Arabia.

Methods:

In a cross-sectional study, 30 pesticide applicators and 32 non-applicators from a vector control unit in Jazan region, Saudi Arabia, were studied. The study participants completed an exposure and medical questionnaire, and a neurobehavioral test battery. Their blood samples were also tested for the measurement of butyryl cholinesterase (BChE).

Results:

The mean blood BChE level was no significantly different between the applicators and non-applicators. Working in pesticide application and chewing khat were significant predictors of the neurological symptoms presentation and neurobehavioral deficits among the study participants. Each factor was associated with about 40% of the symptoms included in the questionnaire. Exposure to pyrethroids was significantly associated with a decrement in symbol digit test latency, tapping (TAP) non-preferred hand, and TAP alternating hands measures, representing the executive and motor speed/coordination functions. Khat chewing was associated with TAP preferred and non-preferred hands and serial digit learning measures, representing the memory and motor speed/coordination functions.

Conclusion:

It seems that being exposed to pyrethroids and chewing khat are associated with neurological and neurobehavioral drawbacks among pesticide applicators.

Effectiveness of a Novel Qigong Meditative Movement Practice for Impaired Health in Flight Attendants Exposed to Second-Hand Cigarette Smoke

This single-arm non-randomized pilot study explores an intervention to improve the health of flight attendants (FA) exposed to second-hand cigarette smoke prior to the smoking ban on commercial airlines. This group exhibits an unusual pattern of long-term pulmonary dysfunction. We report on Phase I of a two-phase clinical trial; the second Phase will be a randomized controlled trial testing digital delivery of the intervention. Subjects were recruited in the Northeastern US; testing and intervention were administered in 4 major cities. The intervention involved 12 h of training in Meditative Movement practices. Based on recent research on the effects of nicotine on fear learning, and the influence of the autonomic nervous system on immune function, our hypothesis was that this training would improve autonomic function and thus benefit a range of health measures. Primary outcomes were the 6-min walk test and blood levels of C-reactive protein. Pulmonary, cardiovascular, autonomic, and affective measures were also taken. Fourteen participants completed the training and post-testing. There was a 53% decrease in high sensitivity C-Reactive Protein (p ≤ 0.05), a 7% reduction in systolic blood pressure (p ≤ 0.05), a 13% increase in the 6-min walk test (p ≤ 0.005), and significant positive changes in several other outcomes. These results tend to confirm the hypothesized benefits of MM training for this population, and indicate that autonomic function may be important in the etiology and treatment of their symptoms. No adverse effects were reported. This trial is registered at ClinicalTrials.gov (https://clinicaltrials.gov/ct2/show/NCT02612389/), and is supported by a grant from the Flight Attendant Medical Research Institute (FAMRI).

Neurological Deficits After Long-term Pyrethroid Exposure

Pyrethroid pesticides have been suggested to be a cause of Parkinson disease and other neurodegenerative diseases. To investigate this, a cross-sectional study was conducted among 120 Bolivian public health vector program spray men, primarily exposed to pyrethroids. Pesticide exposure and central nervous system (CNS) symptoms were determined by a structured interview, whereas neuromotor and neurocognitive performance was assessed using the computerized Behavioral Assessment and Research System and CATSYS system. Individuals exposed to higher levels reported significantly more CNS symptoms (adjusted odds ratio per quintile of cumulative exposure = 2.01 [1.22-3.31]). There was no association seen between pyrethroid exposure and neuromotor performance. Higher spraying intensity was associated with significantly worse neurocognitive performance in structural equation models (adjusted β per quintile = -0.405 [-0.660 to -0.150]), and workers only exposed to pyrethroids performed worse than workers also exposed to other pesticides (adjusted β = -1.344 [-2.224 to -0.464]). Chronic pyrethroid exposure may cause deterioration in neurocognitive performance, and exposure control is recommended.

Mortality from neurodegenerative diseases in a cohort of US flight attendants

BACKGROUND

Concern exists about the potential chronic neurological effects among aircrew of exposure to chemical contaminants from engine oil in aircraft cabin air. We evaluated mortality from neurodegenerative diseases among 11,311 former US flight attendants.

METHODS

Vital status was ascertained through 2007, and life table analyses were conducted to obtain standardized mortality ratios (SMRs).

RESULTS

Amyotrophic lateral sclerosis (ALS) mortality was over twice as high in the cohort as in the US general population, based on nine observed ALS deaths. There was no clear pattern in risk when SMRs for ALS were stratified by exposure duration. Mortality from other neurodegenerative diseases was not elevated.

CONCLUSIONS

Our findings are limited due to small numbers of observed deaths and reliance on mortality data, but suggest that flight attendants may have an increased risk of ALS. Additional research is needed. Am. J. Ind. Med. 59:532-537, 2016. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Trabalho e saúde dos comissários de bordo: uma revisão

Resumo Introdução: com o aumento do número de voos e passageiros, as tarefas atribuídas aos comissários de bordo tornam-se mais complexas, podendo gerar sobrecarga e prejuízo à saúde e ao desempenho desses trabalhadores. Objetivos: identificar e sistematizar os artigos publicados em periódicos científicos, sobre o impacto de fatores físicos, ambientais e organizacionais do trabalho dos comissários de bordo na saúde desses trabalhadores. Método: revisão sistemática da literatura, em português e inglês, utilizando as palavras-chave "aeronave", "cabine", "transporte aéreo", "comissário de bordo" e "trabalho", nas bases de dados ScienceDirect, PubMed, Scopus, ProQuest e SciELO, considerando o período de 1983 a 2013. Resultados: 65 artigos atenderam aos critérios de inclusão. Verificou-se um predomínio de trabalhos com foco em fatores físicos e/ou relacionados à saúde/doença e em fatores relacionados à satisfação no trabalho e poucos estudos abordando a organização do trabalho. Conclusão: os estudos encontrados analisaram os fatores presentes nas situações de trabalho de comissários de bordo de forma isolada. Não foram encontrados estudos que adotassem uma metodologia de análise das situações de trabalho que possibilitasse estabelecer inter-relações entre os fatores determinantes da carga de trabalho desses trabalhadores e os impactos para sua saúde.

The neurotoxicity of organochlorine and pyrethroid pesticides

Organochlorine and pyrethroid compounds represent an old and a new class, respectively, of insecticides. Organochlorines such as DDT, dieldrin, or chlordecone, have been banned, primarily because of environmental issues. DDT is still used in certain countries to fight malaria-bearing mosquitoes, while lindane still finds some limited used against head lice. In contrast, pyrethroids find widespread use because of their efficacy, low environmental persistence, and relatively low mammalian toxicity. Like all insecticides, organochlorines and pyrethroids target the nervous system of insects and of nontarget species. All pyrethroids and DDT interact with the sodium channel; by keeping it open longer, they increase the likelihood of action potentials developing, thus creating a condition of hyperexcitability, whose main clinical sign is tremors. Most other organochlorines (except chlordecone), as well as certain (type II) pyrethroids, block the chloride channels of the GABA-A receptor, and cause seizures. Evidence of an association between exposure to organochlorine and pyrethroid insecticides and neurodegenerative diseases (e.g., Parkinson's disease) is weak, at best.

Usefulness and applicability of infectious disease control measures in air travel: a review

BACKGROUND

Air travel has opened up opportunities for world transportation, but has also increased infectious disease transmission and public health risks. To control disease spread, airlines and governments are able to implement control measures in air travel. This study inventories experiences and applicability of infectious disease control measures.

METHODS

A literature search was performed in PubMed, including studies between 1990 and 2013. Search terms included air travel terms and intervention terms. Interventions were scored according outcome, required resources, preparation, passenger inconvenience and passenger compliance.

RESULTS

Provision of information to travelers, isolation, health monitoring, hygiene measures and vector control reportedly prevent disease spread and are well applicable. Contact tracing can be supportive in controlling disease spread but depend on disease characteristics. Exit and entry screening, quarantine and travel restrictions are unlikely to be very effective in preventing disease spread, while implementation requires extensive resources or travel implications.

CONCLUSIONS

Control measures should focus on providing information towards travelers, isolation, health monitoring and hygiene measures. Appropriateness of measures depends on disease characteristics, and the required resources. As most studies analyze one type of measure in a particular situation, further research comparing the effectiveness of measures is recommended.

Modeling flight attendants' exposures to pesticide in disinsected aircraft cabins

Aircraft cabin disinsection is required by some countries to kill insects that may pose risks to public health and native ecological systems. A probabilistic model has been developed by considering the microenvironmental dynamics of the pesticide in conjunction with the activity patterns of flight attendants, to assess their exposures and risks to pesticide in disinsected aircraft cabins under three scenarios of pesticide application. Main processes considered in the model are microenvironmental transport and deposition, volatilization, and transfer of pesticide when passengers and flight attendants come in contact with the cabin surfaces. The simulated pesticide airborne mass concentration and surface mass loadings captured measured ranges reported in the literature. The medians (means ± standard devitions) of daily total exposure intakes were 0.24 (3.8 ± 10.0), 1.4 (4.2 ± 5.7), and 0.15 (2.1 ± 3.2) μg day(-1) kg(-1) of body weight for scenarios of residual application, preflight, and top-of-descent spraying, respectively. Exposure estimates were sensitive to parameters corresponding to pesticide deposition, body surface area and weight, surface-to-body transfer efficiencies, and efficiency of adherence to skin. Preflight spray posed 2.0 and 3.1 times higher pesticide exposure risk levels for flight attendants in disinsected aircraft cabins than top-of-descent spray and residual application, respectively.

A global airport-based risk model for the spread of dengue infection via the air transport network

The number of travel-acquired dengue infections has seen a consistent global rise over the past decade. An increased volume of international passenger air traffic originating from regions with endemic dengue has contributed to a rise in the number of dengue cases in both areas of endemicity and elsewhere. This paper reports results from a network-based risk assessment model which uses international passenger travel volumes, travel routes, travel distances, regional populations, and predictive species distribution models (for the two vector species, Aedes aegypti and Aedes albopictus) to quantify the relative risk posed by each airport in importing passengers with travel-acquired dengue infections. Two risk attributes are evaluated: (i) the risk posed by through traffic at each stopover airport and (ii) the risk posed by incoming travelers to each destination airport. The model results prioritize optimal locations (i.e., airports) for targeted dengue surveillance. The model is easily extendible to other vector-borne diseases.

Computational fluid dynamics modeling of transport and deposition of pesticides in an aircraft cabin

Spraying of pesticides in aircraft cabins is required by some countries as part of a disinsection process to kill insects that pose a public health threat. However, public health concerns remain regarding exposures of cabin crew and passengers to pesticides in aircraft cabins. While large scale field measurements of pesticide residues and air concentrations in aircraft cabins scenarios are expensive and time consuming, Computational Fluid Dynamics (CFD) models provide an effective alternative for characterizing concentration distributions and exposures. This study involved CFD modeling of a twin-aisle 11 row cabin mockup with heated manikins, mimicking a part of a fully occupied Boeing 767 cabin. The model was applied to study the flow and deposition of pesticides under representative scenarios with different spraying patterns (sideways and overhead) and cabin air exchange rates (low and high). Corresponding spraying experiments were conducted in the cabin mockup, and pesticide deposition samples were collected at the manikin's lap and seat top for a limited set of five seats. The CFD model performed well for scenarios corresponding to high air exchange rates, captured the concentration profiles for middle seats under low air exchange rates, and underestimated the concentrations at window seats under low air exchange rates. Additionally, both the CFD and experimental measurements showed no major variation in deposition characteristics between sideways and overhead spraying. The CFD model can estimate concentration fields and deposition profiles at very high resolutions, which can be used for characterizing the overall variability in air concentrations and surface loadings. Additionally, these model results can also provide a realistic range of surface and air concentrations of pesticides in the cabin that can be used to estimate potential exposures of cabin crew and passengers to these pesticides.

Exposure of flight attendants to pyrethroid insecticides on commercial flights: urinary metabolite levels and implications

Pyrethroid insecticides have been used for disinsection of commercial aircrafts. However, little is known about the pyrethroids exposure of flight attendants. The objective of the study was to assess pyrethroids exposure of flight attendants working on commercial aircrafts through monitoring the urinary pyrethroids metabolite levels. Eighty four urine samples were collected from 28 flight attendants, 18-65 years of age, with seventeen working on planes that were non-disinsected, and eleven working on planes that had been disinsected. Five urinary metabolites of pyrethroids were measured using gas chromatographic-mass spectrometric method: 3-phenoxybenzoic acid (3-PBA), cis-/trans-3-(2,2-Dichlorovinyl)-2,2-dimethylcyclo-propane carboxylic acid (cis-/trans-Cl2CA), cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclo-propane-1-carboxylic acid (cis-Br2CA) and 4-fluoro-3-phenoxybenzoic acid (4F-3-PBA). Flight attendants working on disinsected planes had significantly higher urinary levels of 3-PBA, cis- and trans-Cl2CA in pre, post- and 24-h-post flight samples than those on planes which did not report having been disinsected. Urinary levels of cis-Br2CA and 4F-3-PBA did not show significant differences between the two groups. Flight attendants working on international flights connected to Australia had higher urinary levels of 3-PBA, cis- and trans-Cl2CA than those on either domestic and other international flights flying among Asia, Europe and North America. Post-disinsection duration (number of days from disinsection date to flight date) was the most significant factor affecting the urinary pyrethroid metabolites levels of 3-PBA, cis- and trans-Cl2CA of the group flying on disinsected aircraft. It was concluded that working on commercial aircraft disinsected by pyrethroids resulted in elevated body burdens of 3-PBA, cis- and trans-Cl2CA.

Sampling scheme for pyrethroids on multiple surfaces on commercial aircrafts

A wipe sampler for the collection of permethrin from soft and hard surfaces has been developed for use in aircraft. "Disinsection" or application of pesticides, predominantly pyrethrods, inside commercial aircraft is routinely required by some countries and is done on an as-needed basis by airlines resulting in potential pesticide dermal and inhalation exposures to the crew and passengers. A wipe method using filter paper and water was evaluated for both soft and hard aircraft surfaces. Permethrin was analyzed by GC/MS after its ultrasonication extraction from the sampling medium into hexane and volume reduction. Recoveries, based on spraying known levels of permethrin, were 80-100% from table trays, seat handles and rugs; and 40-50% from seat cushions. The wipe sampler is easy to use, requires minimum training, is compatible with the regulations on what can be brought through security for use on commercial aircraft, and readily adaptable for use in residential and other settings.

Investigating ozone-induced decomposition of surface-bound permethrin for conditions in aircraft cabins

The reaction of ozone with permethrin can potentially form phosgene. Published evidence on ozone levels and permethrin surface concentrations in aircraft cabins indicated that significant phosgene formation might occur in this setting. A derivatization technique was developed to detect phosgene with a lower limit of detection of 2 ppb. Chamber experiments were conducted with permethrin-coated materials (glass, carpet, seat fabric, and plastic) exposed to ozone under cabin-relevant conditions (150 ppb O(3), 4.5/h air exchange rate, <1% relative humidity, 1700 ng/cm(2) of permethrin). Phosgene was not detected in these experiments. Reaction of ozone with permethrin appears to be hindered by the electron-withdrawing chlorine atoms adjacent to the double bond in permethrin. Experimental results indicate that the upper limit on the reaction probability of ozone with surface-bound permethrin is approximately 10(-7). Extrapolation by means of material-balance modeling indicates that the upper limit on the phosgene level in aircraft cabins resulting from this chemistry is approximately 1 microg/m(3) or approximately 0.3 ppb. It was thus determined that phosgene formation, if it occurs in aircraft cabins, is not likely to exceed relevant, health-based phosgene exposure guidelines.

PRACTICAL IMPLICATIONS

Phosgene formation from ozone-initiated oxidation of permethrin in the aircraft cabin environment, if it occurs, is estimated to generate levels below the California Office of Environmental Health Hazard Assessment acute reference exposure level of 4 microg/m(3) or approximately 1 ppb.

Pyrethrin and pyrethroid illnesses in the Pacific northwest: a five-year review

OBJECTIVE

Pyrethrin and pyrethroid insecticides are commonly applied in homes and businesses and on some agricultural crops. This research used a two-state regional approach to analyze reports of acute pesticide poisonings due to pyrethrin and pyrethroid insecticides.

METHODS

The Washington State Department of Health and the Oregon Public Health Division collected pesticide poisoning surveillance data from 2001 through 2005. Cases were included if they involved exposure to at least one pyrethrin or pyrethroid insecticide. Descriptive statistics were calculated; differences between categories were assessed using Chi-square analysis.

RESULTS

A total of 407 cases fit our definition. Overall, the rate of poisoning in Oregon was significantly higher than in Washington (incidence rate ratio 1.70, 95% confidence interval 1.40, 2.07), and rates for both states generally increased during the time period. For both states, most exposures resulted in low severity illnesses (92%), and most were classified as possible cases (73%). Only about one-fourth of cases were related to a person's work. The most common category of clinical signs and symptoms of illness was respiratory (52% of cases), followed by neurological (40% of cases). Exposure route was predominantly inhalation; there was no association between route and case severity. There was a significant association between illness severity and losing time from work or regular activities (p<0.0001).

CONCLUSIONS

Although the majority of pyrethrin and pyrethroid poisoning cases were low in severity, adverse reactions have occurred, as transpired in Oregon in 2005. Regional analysis has the potential to improve the surveillance system and provide unique opportunities for targeting preventive interventions.

Calculating human exposure to endocrine disrupting pesticides via agricultural and non-agricultural exposure routes

Endocrine Disrupting Chemicals (EDCs) are of increasing concern because of their potential impacts on the environment, wildlife and human health. Pesticides and some pesticide metabolites are an important group of EDC, and exposure to them is a poorly quantified source of human and environmental exposure to such chemicals generally. Models for estimating human exposure to Endocrine Disrupting (ED) pesticides are an important risk management tool. Probabilistic models are now being used in addition to deterministic ones in all areas of risk assessment. These can provide more realistic exposure estimates, because they are better able to deal with variation and uncertainty more effectively and better inform risk management decisions. Deterministic models are still used and are of great value where exposure data are scarce. Models or groups of models that provide holistic human ED pesticide exposure estimates are required if the risk posed to humans by ED pesticides is to be better assessed. Much more research is needed to quantify different exposure routes such as exposure from agricultural spray drift and the medical use of pesticides to develop such models. Most available probabilistic models of human exposure were developed in the USA and require modification for use elsewhere. In particular, datasets equivalent to those used to create and apply the American models are required. This paper examines the known routes of human pesticide exposure with particular reference to ED pesticides and their quantification as unlike pesticides generally, many ED pesticides are harmful at very low doses, especially if exposure occurs during sensitive stages of development, producing effects that may not manifest for many years or that affect descendants via epigenetic changes. It also summarises available deterministic and probabilistic models commonly used to calculate human exposure. The main requirement if such models are to be used in the UK is more quantitative data on the sources and pathways of human ED pesticide exposure.