Establishing health-based biological exposure limits for pesticides : A proof of principle study using mancozeb

Pesticides represent an economical, labor-saving, and efficient tool for pest management, but their intrinsic toxic properties may endanger workers and the general population. Risk assessment is necessary, and biological monitoring represents a potentially valuable tool. Several international agencies propose biological exposure indices (BEI), especially for substances which are commonly absorbed through the skin. Biological monitoring for pesticide exposure and risk assessment seems a natural choice, but biological exposure limits (BEL) for pesticides are lacking. This study aims at establishing equivalent biological exposure limits (EBEL) for pesticides using real-life field data and the Acceptable Operator Exposure Level (AOEL) of mancozeb as the reference. This study included a group of 16 vineyard pesticide applicators from Northern Italy, a subgroup of a more extensive study of 28 applicators. Their exposure was estimated using \u201cpatch\u201d and \u201chand-wash\u201d methodologies, together with biological monitoring of free ethylene-bis-thiourea (ETU) excretion in 24-h pre- and post-exposure urine samples. Modeling was done using univariate linear regression with ETU excretion as the dependent variable and the estimated absorbed dose as the independent variable. The median skin deposition of mancozeb in our study population was 125 \u3bcg, leading to a median absorbed dose of 0.9 \u3bcg/kg. The median post-exposure ETU excretion was 3.7 \u3bcg. The modeled EBEL for mancozeb was 148 \u3bcg of free ETU or 697 \u3bcg of total ETU, accounting for around 75% of the maximum theoretical excretion based on a mass balance model. Although preliminary and based on a small population of low-exposed workers, our results demonstrate a procedure to develop strongly needed biological exposure limits for pesticides

Developing approaches to control SARS-CoV-2 in a public hospital

The Territorial Public Health Care Company (in Italian, ASST) of the Saints Paolo e Carlo of Milano includes two large public hospitals, and several outpatients and territorial healthcare services. It employs 5642 workers. The outbreak of novel coronavirus disease 2019 (COVID-19) reached our ASST in the last week of February when a doctor in the Intensive Care Unit of the San Paolo Hospital was diagnosed with COVID-19. Our Occupational Health Unit immediately introduced measures to control the epidemic. Our approach was based on contact tracing and isolation of asymptomatic infected workers. A \u2018close contact\u2019 was defined as a person who had face-to-face contact or spent at least 15 min in an indoor environment with a positive subject (patient, colleague or relative) without any protective equipment (surgical mask). From 27 February to 23 April we tested 2907 workers (51% of the total workforce) with nasopharyngeal swabs (NPS) using rtPCR for SARS-CoV-2 detection [1,2], with positive results in 152 hospital and 33 territorial workers (3% of the total workforce). All the infected workers were asked to fill in a daily electronic data collection form for the duration of the infection. About 50% remained substantially asymptomatic for the quarantine period, which ended when the workers underwent two NPS on two consecutive days with a negative result. The time to recovery took from 12\u201347 days, with a median duration of about 30 days, which is longer than normally expected. Symptomatic workers showed only very mild symptoms; mainly loss/change of smell and taste. Four were hospitalized but none had severe or life-threatening infection. The data suggest that the \u2018active search approach\u2019 is more effective in closed communities such as groups of healthcare workers than generalized testing. We have started a retrospective survey of 100 positive workers studying symptoms, source of exposure and co-morbidities using a modified version of the \u2018WHO novel coronavirus acute respiratory infection clinical characterization data tool\u2019, administered by telephone interview. Finally, in order to prepare for future outbreaks, we are testing a novel telemedicine approach enabling us to follow quarantined workers with a digital platform with a mobile phone app that provides remote video examinations and online symptoms and health parameter checking (body temperature, oxygen saturation, etc.). The platform facilitates rapid intervention. Using this approach, we can follow a large cohort of workers with continuous monitoring. The tool may also be able to reduce the rate of patients\u2019 hospitalization. We are also comparing those with positive and negative swabs using a rapid immunochromatographic assay for the detection of IgG and IgM antibodies to SARS-CoV-2 virus in whole blood to assess potential immunity. Preliminary results are promising for IgG, even though the protective capacity of this immunoglobulin is still unknown

Assessment of penconazole exposure in winegrowers using urinary biomarkers

Penconazole (PEN) is a fungicide used in agriculture. The aim of this work was to evaluate the exposure to PEN in vineyard workers focusing on urinary biomarkers. Twenty-two agricultural workers were involved in the study; they were investigated during PEN applications and re-entry work, performed for 1-4 consecutive working days, for a total of 42 mixing and applications and 12 re-entries. Potential and actual dermal exposure, including hand exposure, were measured using pads and hand washes. Urine samples were collected starting before the first application, continuing during the work shift, and ending 48\u202fh after the last shift. The determination of PEN in dermal samples and PEN metabolites in urine was performed by liquid chromatography tandem mass spectrometry. Dermal potential body exposure and actual total exposure showed median levels ranging from 18 to 3356\ub5g and from 21 to 111\u202f\ub5g, respectively. Urinary monohydroxyl-derivative PEN-OH was the most abundant metabolite; its excretion rate peaked within 24\u202fh after the work shift. In this period, median concentrations of PEN-OH and the carboxyl-derivative PEN-COOH ranged from 15.6 to 27.6\u202f\ub5g/L and from 2.5 to 10.2\u202f\ub5g/L, respectively. The concentration of PEN-OH during the work shift, in the 24\u202fh after and in the 25-48\u202fh after the work shift were correlated with actual body and total dermal exposure (Pearson's r from 0.279 to 0.562). Our results suggest that PEN-OH in the 24\u202fh post-exposure urine is a promising candidate for biomonitoring PEN exposure in agricultural workers

Environmental and biological monitoring for the identification of main exposure determinants in vineyard mancozeb applicators

Grapevine is a vulnerable crop to several fungal diseases often requiring the use of ethylenebisdithiocarbamate (EBDC) fungicides, such as mancozeb. This fungicide has been reported to have goitrogenic, endocrine disrupting, and possibly immunotoxic effects. The aim of this study was to assess workers' exposure in two scenarios of mancozeb application and analyse the main determinants of exposure in order to better understand their mechanism of influence. Environmental monitoring was performed using a modified Organisation for Economic Co-operation and Development (OECD) "patch" methodology and by hand-wash collection, while mancozeb's metabolite, ethylenethiourea (ETU), was measured in 24-h preexposure and postexposure urine samples. Liquid chromatography-mass spectrometry was used for determination of mancozeb and ETU in different kinds of samples. Closed tractor use resulted in 40 times lower potential exposure compared with open tractor. Coveralls reduced skin exposure 4 and 10 times in case of open and closed tractors, respectively. Gloves used during application resulted in 10 times lower hand exposure in open but increased exposure in closed tractors. This study has demonstrated that exposure to mancozeb is low if safe occupational hygiene procedures are adopted. ETU is confirmed as suitable biological marker of occupational exposure to mancozeb, but the absence of biological exposure limits significantly reduces the possibility to interpret biological monitoring results in occupationally exposed workers

Sorveglianza sanitaria in agricoltura : l\u2019esperienza del Centro Internazionale per la Salute Rurale dell\u2019Azienda Ospedaliera San Paolo di Milano

OCCUPATIONAL HEALTH SURVEILLANCE IN AGRICULTURE: THE EXPERIENCE OF THE INTERNATIONAL CENTRE FOR RURAL HEALTH. The results of the activities of occupational health surveillance in agriculture carried out by the International Centre for Rural Health since 2008 are described.The activities involve 800 workers employed in 260 farms in the Region of Lombardy (Italy). The types of farms reflect the vocation toward agricultural sector of the Po Valley and the most representative tasks are related to animal care and use of agricultural machinery. Based on the specific risks, workers are provided with preventive and periodic examinations, and complementary laboratory and instrumental evaluations (hearing and respiratory functions, electrocardiography), related to the different risk factors present in the enterprises. The occupational health priorities identified are, for the time being, noise-induced hearing loss and insufficient immunization against tetanus

EXPLORING NOVEL APPROACHES TO PESTICIDE EXPOSURE AND RISK ASSESSMENT

Introduction. Agrochemicals, short from agricultural chemicals, is a term used for various chemical products which are commonly used in agriculture. The most famous representative example of agrochemicals are pesticides, but it may also include fertilizers, hormones or similar chemical growth agents, as well as raw animal manure. Even as an active substance is authorized in European Union, and products containing this active substance are authorized and marketed, there is still a need for risk assessment to communicate and to manage risk with regard to the different risk groups, workers and the general population as a whole. Overall Goal. The goal of this effort is the creation of Exposure and Risk Profiles, as a reliable, scientifically based way to forecast pesticide exposure and workers\u2019 risk in typical scenarios from a minimum set of available information, aimed at performing a preliminary risk assessment even without the need of \u201cin field\u201d measurements. Methodology. To reach our goal we have conducted a wide published literature search to define the process of pesticide application and the most common exposure determinants. Then we conducted two real-life field studies on exposure to pesticide in different use scenarios in the vineyards of the Region of Lombardy (one study in the framework of the ACROPOLIS project of the European Union, and another financed by INAIL). We collected field information in the form of a structured questionnaire, with a goal to record the variables previously identified as important modifiers of pesticide exposure. Also we collected exposure measurements, using two methodologies: skin pads and whole-body method, following in principle the OECD guidelines. Finally, we used the results from the field to develop a method that allows for a re-use of field data in risk assessment, by creating a Risk Assessment Scheme which can be used to assess risk in the field, without doing any measurements. Results. We report the main phases of pesticide work and variables, together with their influence, as a result of our wide literature search. Also we report the results of two field studies, first on 7 workers applying Tebuconazole on 12 work-days, and second on 28 workers applying Mancozeb on 38 work-days. Finally, we show a proposed approach to using field measurements from our study in the Region of Lombardy to perform future risk-assessment in one defined scenario of closed and filtered tractors. Discussion and Conclusions. Our work has tackled the problem of risk assessment for pesticide exposure in agriculture, which has been unfairly neglected in the past years. Through the use of literature data, field studies and computational modelling, we have managed to analyze and summarize the characteristics of pesticide application in agriculture, explore the real-life field conditions during pesticide application in vineyards in Italy, collect the field measurements necessary to do exposure and risk assessment, and to develop a method to use the data collected to produce a Risk Assessment Scheme. The study results and the above mentioned tool represent a step forward towards rapid, simple and scientifically based risk assessment in real-life conditions of pesticide application in agriculture

Duration of Skin Exposure: a Neglected Variable in Absorbed Dose Assessment

The use of pesticides has become unavoidable in agriculture as it ensures the massive production of food crops and their global trade, as well as solves public health problems by eradicating vectors of human diseases such as malaria. Besides risk assessment done in the pre-marketing phase, field studies allow for the re-evaluation of exposure and risk in real-life working conditions, opening new possibilities for risk assessment and modeling. In agriculture, special attention must be given to the skin as the main route of exposure, but the fixed fractional approach to dermal absorption might not represent the perfect solution to absorbed dose assessment. Here we present a practical method for integrating the information on the duration of exposure into the absorbed dose assessment, using a group of mancozeb applicators as a case study. Assumption of an 8-hour exposure resulted in a gross overestimation of absorbed dose from hands\u2019 exposure. Absorbed dose from body exposure was overestimated in those workers working less than 8 hours, but somewhat underestimated in those working more than 8 hours, which is common in agriculture. In total, an 80% reduction of the absorbed dose estimate resulted from the introduction of the duration of exposure as a factor. This reduction did not influence risk assessment significantly for substances with low toxicity such as mancozeb, but implications for modeling might be much more important

Pesticides

Pesticides are substances or mixtures used to control living organisms that damage crops or goods, transmit or cause diseases and other unwanted events, such as the uncontrolled expansion of endogenous living species, or infestation by non\u2010native ones. Unwanted living organisms include animals, such as insects and rodents, invading plants, such as weeds and ornamental flowers, shrubs and trees, microorganisms and viruses that cause transmittable diseases to plants, animals, and humans

Improving the Quality of Toxicological Research Findings Using Modern Principles of Reproducible Research

Reproducibility represents the foundation of scientific work and publications, and the materials and methods section in each published article should allow any researcher to repeat the experiment in question and get the same or similar results. Nevertheless, in most scientific papers the data analysis procedure is rarely described well, and it often contains just the basic information on statistical procedures performed. We present all of the basic steps in doing reproducible data analysis, with all the advantages and disadvantages over the non-reproducible methods, on a case study of pesticide exposure and risk assessment. Data is imported from multiple sources (text, excel, access database), and basic description of acquired data, visual and numerical comparison between groups, and modelling of data acquired in real-life studies of pesticide exposure in agriculture are presented. The final products of the data analysis process, tables and figures which are ready for the revision process, are compiled using the R Language and Environment for Statistical Computing and additional packages. Considering the more strict requirements for funding and the increased competition, as well as the slow (but certain) move towards open access, open review and data exchange, doing data analysis the reproducible way will become inevitable in toxicology, as well as other scientific fields. Popularization and training on using free statistical and reproducible research tools should be a priority for young researchers entering this field, as this will result in the improvement of the quality of toxicological research, leading to easier publishing

Biological Monitoring for Pesticide Risk Assessment in Farmers and Rural Population with a Tiered Protocol

OBJECTIVES: The assessment of exposure and of exposure-related risk for pesticides is a burdensome and expensive task. Since farmers are often exposed to many active substances, several times per year, at different working and environmental conditions, and their families, including children pregnant and breastfeeding women, the elderly, share the same environment, biological monitoring is the most promising technique for this purpose. However, there is still a difficulty to use the actual results of biological monitoring to assess individual risk, mainly due to the lack of suitable exposure limits. METHODS: To overcome this knowledge gap, the ICRH is currently establishing provisional Equivalent Biological Exposure Limits (EBELs) for priority pesticides. This multi-tiered approach exploits the extensive, although scattered information available in the scientific literature, in the authorization documents available from regulatory bodies, and the analysis of results from field studies. RESULTS: The established theoretical and computational basis and examples of the employed approach will be presented. In particular, it is possible to discriminate occupational exposure from agricultural tasks, including re-entry into treated fields, repair of agricultural equipment, from that of everyday life, from drinking water and from food. As proof-of-principle, the proposal of provisional EBELs for some priority pesticides, and an application to different agricultural tasks performed by Italian wine growers will be demonstrated. CONCLUSIONS: The establishment of a robust protocol for the determination of EBELs will allow individual risk assessment for farmers, for their families and for the general population of rural areas with moderate effort and cost. REFERENCES: Rubino FM, Mandic-Rajcevic S, Colosio C. et al. Toxicol Lett. 2012 Apr 25;210(2):189-97. Colosio C, Rubino FM, Alegakis A, Mandic-Rajcevic S, et al. Toxicol Lett. 2012 Aug 13;213(1):49-56