Inadvertent ingestion exposure: hand- and object-to-mouth behavior among workers

The relevance of oral exposure in the workplace: a systematic review and meta-analysis

Introduction

The inclusion of all relevant exposure routes in the exposure assessment is essential for the protection of workers. However, under European chemical regulations but also for workplace risk assessments according to occupational safety and health (OSH) requirements, the quantitative assessment of oral exposure is usually neglected assuming good occupational hygiene. In contrast, several studies point to the importance of unintentional ingestion in the workplace. To our knowledge, there is no systematic analysis of the extent of this exposure route.

Methods

Therefore, the aim of this study was to assess systematically the current knowledge on the relevance of occupational oral exposure using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) method. Five electronic databases and nine institutional websites were searched for all publications on the relevance. The data were extracted into a concept matrix. In the subsequent meta-analysis, the identified conclusions on the relevance were analyzed. In addition, the measurement methods or modeling approaches that were described for occupational oral exposure were determined as well as the potentially relevant workplaces and substances.

Results

In total, 147 studies were included in this analysis that contain a general or several, differentiated assessments of the relevance of occupational oral exposure. Nine of these studies assessed this exposure route as irrelevant. However, 123 studies considered oral exposure as potentially contributing and 80 studies explicitly identified it as relevant. 78 and 94 of the publications described modeling and measurement approaches, respectively. The workplaces frequently identified as potentially or explicitly relevant were other indoor, other industrial or recycling workplaces. Analogously, metals, dust and powders or pesticides were the most frequently investigated substance groups.

Discussion

As several studies assessed occupational oral exposure as relevant in the context of different workplaces and substances, further investigation of this exposure route is needed. This systematic review and meta-analysis serve as a basis for further development of feasible assessment methods for this route of exposure.

Risk factors for diarrheagenic Escherichia coli infection in children aged 6-24 months in peri-urban community, Nairobi, Kenya

Escherichia coli commonly inhabits the gut of humans and animals as part of their microbiota. Though mostly innocuous, some strains have virulence markers that make them pathogenic. This paper presents results of a cross-sectional epidemiological study examining prevalence of diarrheagenic E. coli (DEC) pathotypes in stool samples of asymptomatic healthy children (n = 540) in Dagoretti South subcounty, Nairobi, Kenya. E. coli was cultured and pathotyped using PCR to target specific virulence markers associated with Shiga-toxin, enteropathogenic, enterotoxigenic, enteroaggregative, entero-invasive and diffusely adherent E. coli. Overall prevalence of DEC pathotypes was 20.9% (113/540) with enteropathogenic E. coli being the most prevalent (34.1%), followed by enteroaggregative E. coli (23.5%) and Shiga-toxin producing E. coli (22.0%) among positive samples. We found evidence of co-infection with multiple pathotypes in 15% of the positive samples. Our models indicated that at the household level, carriage of DEC pathotypes in children was associated with age group [12-18 months] (OR 1.78; 95%CI 1.03-3.07; p = 0.04), eating matoke (mashed bananas) (OR 2.32; 95%CI 1.44-3.73; p = 0.001) and pulses/legumes (OR 1.74; 95%CI 1.01-2.99; p = 0.046) while livestock ownership or contact showed no significant association with DEC carriage (p>0.05). Our findings revealed significant prevalence of pathogenic DEC circulating among presumptive healthy children in the community. Since there has been no previous evidence of an association between any food type and DEC carriage, unhygienic handling, and preparation of matoke and pulses/legumes could be the reason for significant association with DEC carriage. Children 12-18 months old are more prone to DEC infections due to exploration and hand-to-mouth behavior. A detailed understanding is required on what proportion of positive cases developed severe symptomatology as well as fatal outcomes. The co-infection of pathotypes in the rapidly urbanizing environment needs to be investigated for hybrid or hetero-pathotype circulation that have been implicated in previous infection outbreaks.

A systematic characterization of soil/dust ingestion for typical subpopulations in China

An accurate assessment of human exposure to pollutants through the ingestion of dust and/or soil particles depends on a thorough understanding their rate of human ingestion. To this end, we investigated the load and size distribution patterns of dust/soil particles on the hands of three typical subpopulations, including preschoolers, college students, and security guards (outdoor workers). The geometric mean diameter of dust/soil particles on hands was observed to be 38.7 ± 11.2, 40.0 ± 12.1, and 36.8 ± 10.4 μm for preschoolers, college students, and security guards, respectively. The particle size distribution differed between subpopulations: Preschoolers were more exposed to fine particles, whereas security guards were exposed to more coarse particles. The geometric means of dust/soil particle loading on the hands were 0.126, 0.0163, and 0.0377 mg/cm2 for preschoolers, college students, and security guards, respectively. Males had statistically higher dust/soil particle loadings on hands than females, notably for preschoolers and college students; preschoolers with frequent hand contact with the bare ground had higher dust/soil particle loadings compared to those of peers in contact with commercial and residential grounds. The mean total dust/soil particle ingestion rate was estimated to be 245, 19.7, and 33.1 mg/day for preschoolers, college students, and security guards, respectively. Our estimates for college students and security guards are close to the consensus central-tendency values recommended by the U.S. EPA's Exposure Factor Handbook for American adults, whereas the estimates for children are much higher than the upper percentile values recommended for American children.

Occupational health and safety, metal exposures and multi-exposures health risk in Canadian electronic waste recycling facilities

Electronic waste recycling (e-recycling) involves manual operations that expose workers to toxic metals. We aim to describe occupational health and safety practices and workers' exposures to metals in the Canadian formal e-recycling industry, and to estimate the health risk associated with multiple exposures. This cross-sectional study documented practices through observations and questionnaires, and assessed metal exposures using personal air samples and biomarkers. Health risks were estimated relative to recognised occupational exposure guidelines, and using an additive approach for consideration of multiple exposures. Six e-recycling and one commercial recycling facilities were investigated, and the metal exposures of 99 workers (23 women) were measured. In most facilities, dust control was inadequate and personal protective equipment was improperly worn. In e-recycling, lead was detected in all air samples and in most blood samples, up to 48 µg/m³ and 136 µg/l, respectively. Other quantified metals included beryllium, mercury, arsenic, barium, cadmium, chrome, cobalt, copper, indium, manganese, nickel and yttrium. When handling cathode ray tube screens, workers were 4.9 times and 8.5 times more likely to be exposed to lead and yttrium, respectively, than workers who were not assigned to a specific type of electronics. Overall, exposures were largely associated with facility size and airborne dust concentration. The additive hazard indices for airborne exposures raised concerns for kidney disorders, for peripheral and central nervous systems, and for the male reproductive system. Minimizing airborne dust through collective control methods and adequately using personal protection should reduce metal exposures and associated health risks in this growing industry.

Microbial Contamination in the Coffee Industry: An Occupational Menace besides a Food Safety Concern?

Respiratory abnormalities among workers at coffee roasting and packaging facilities have already been reported; however, little is known about microbiological contamination inside coffee production facilities. This study intends to assess the microbial contamination (fungi and bacteria) in two coffee industries from Brazil with a multi-approach protocol for sampling and for subsequent analyses using four main sources of samples: filtering respiratory protection devices (FRPD) used by workers, settled dust, electrostatic dust cloths (EDC) and coffee beans. The fungal contamination in the assessed industries was also characterized through the molecular detection of toxigenic species and antifungal resistance. Total bacteria contamination presented the highest values in FRPD collected from both industries (7.45 × 104 CFU·m-2; 1.09 × 104 CFU·m-2). Aspergillus genera was widespread in all the environmental samples collected and sections with clinical relevance (Fumigati) and with toxigenic potential (Nigri and Circumdati) were recovered from FRPD. Circumdati section was observed in 4 mg/mL itraconazole. Sections Circumdati (EDC, coffee beans and settled dust) and Nidulantes (EDC, coffee beans and FRPD) were detected by qPCR. Some of the targeted Aspergillus sections that have been identified microscopically were not detected by qPCR and vice-versa. Overall, this study revealed that microbial contamination is a potential occupational risk in the milling stage and should be tackled when assessing exposure and performing risk assessment. In addition, a multi-sampling campaign should be the approach to follow when assessing microbial contamination and FRPD should be included in this campaign. Occupational exposure to mycotoxins should be considered due to high fungal diversity and contamination. A One Health approach should address these issues in order to prevent consumption of coffee crops and beans infected by fungi and, more specifically, to avoid widespread azole resistance.

PFAS use in electronic products and exposure risks during handling and processing of e-waste: A review

Poly- and perfluorinated alkyl substances (PFAS) have been and are used in electronic products due to their unique properties that improve product quality and performance. Ubiquities and persistence of some PFAS detected in environmental samples (water, soil, air) have attracted much attention and regulatory actions in recent years. This review provides an overview of PFAS use in electronic components; trends in quantities of e-waste generation; PFAS exposure pathways during e-waste handling and processing; reported PFAS in environmental samples and samples of serum, blood, and hair collected from people living near and working at e-waste processing sites. Processes used for manufacturing electronic components (e.g., embedded processes, additive manufacturing) make recycling or materials recovery from discarded electronic units and components very difficult and unfeasible. Exposure during numerous processing steps for materials recovery and scavenging at disposal sites can result in PFAS intake through inhalation, ingestion, and dermal routes. Chemical risk assessment approaches have been continuously evolving to consider chemical-specific dosimetric and mechanistic information. While the metabolic fate of PFAS is not well understood, some PFAS bioaccumulate and bind to proteins (but not to lipids) in biota and humans due to their surface-active characteristics and very low solubility in water and fat. It is difficult to associate the adverse health effects due to exposure to e-waste directly to PFAS as there are other factors that could contribute to the observed adverse effects. However, PFAS have been detected in the samples collected from different environmental compartments (e.g., water, soil, leachate, blood sera, rainwater) at and near e-waste processing sites, landfills, and near electronics and optoelectronics industries indicating that e-waste collection, processing, and disposal sites are potential PFAS exposure locations. Better monitoring of e-waste handling sites and detailed epidemiological studies for at risk populations are needed for assessing potential health risks due to PFAS exposure at these sites.

Key considerations for assessing soil ingestion exposures among agricultural workers

BACKGROUND

Soil ingestion is a critical, yet poorly characterized route of exposure to contaminants, particularly for agricultural workers who have frequent, direct contact with soil.

OBJECTIVE

This qualitative investigation aims to identify and characterize key considerations for translating agricultural workers' soil ingestion experiences into recommendations to improve traditional exposure science tools for estimating soil ingestion.

METHODS

We conducted qualitative in-depth interviews with 16 fruit and vegetable growers in Maryland to characterize their behaviors and concerns regarding soil contact in order to characterize the nature of soil ingestion in the agricultural context.

RESULTS

We identified and discussed four emergent themes: (1) variability in growers' descriptions of soil and dust, (2) variability in growers' soil contact, (3) growers' concerns regarding soil contact, (4) growers' practices to modify soil contact. We also identified environmental and behavioral factors and six specific agricultural tasks that may impact soil ingestion rates.

SIGNIFICANCE

Our investigation fills an important gap in occupational exposure science methodology by providing four key considerations that should be integrated into indirect measurement tools for estimating soil ingestion rates in the agricultural context. Specifically, a task-based framework may provide a structure for future investigations of soil contact that may be useful in other populations.

Quantitative skin exposure assessment of metals: A case study

This article provides guidance into the quantitative risk assessment of skin exposures to metals. The use of wipe sampling methodologies has been shown to be standardised and effective for skin exposure assessment to metals. However, there is a lack of guidance documents and frameworks available to evaluate the level of health risk to workers from skin exposures to metals. Adverse health effects from exposures to metals have been described in the literature (Fernández-Nieto et al. 2006; Herman et al. 2006; Kreiss et al. 1996). Monitoring of workplace exposures typically focuses on the assessment of respiratory exposures. To provide a safe workplace there is a need to ensure all routes of exposure are risk assessed and controlled. The goal of this article was to develop skin (surface) exposure limits to metals, using the construction industry as a test environment, to quantitatively assess worker health risk of skin exposures to metals. This research concluded it was not feasible to establish single quantitative skin exposure limits to metals due to the many assumptions surrounding dermal exposures. A range of acceptable exposure limits are presented.

An observational study of hand-to-face contact via videotaping of Korean older people in daily life settings

OBJECTIVES

This study aimed to quantify hand-to-face contact (HFC) and identify the related factors that influence HFC in the daily life of Korean older people.

METHODS

From November 20-December 4, 2018, 30 older people were enrolled and were each videotaped for their daily activities for two hours in total. The videotaped HFC data were classified by frequency, duration, site of contact, and as self-contact with membranes (eye, nose and mouth) or non-membranes (head, forehead, chin, cheek and ear).

RESULTS

Of the 4826 self-contacts, 1311 HFC (560 membrane contacts [42.7%], 751 non-membrane contacts [57.3%]) were observed in 60 person-hours. The mean contact frequency (mean/person) of membrane and non-membrane contact was 18.7 times (nose, 9.3; mouth, 5.7; and eye, 3.6) and 24.6 (highest with the chin, 8.5), respectively. The mean contact duration (seconds/contact) for membrane and non-membrane contacts was 3.4 s (nose, 3.1; mouth, 3.7; and eye, 3.0) and 6.3 s (highest with the chin, 8.2), respectively. Contact exposure (frequency-duration/second/person) of the membrane and non-membrane was 3510.7 (nose, 1002.3; mouth, 639.3; and eye, 92.3) and 11,727.1 (highest with the chin, 2,965.6), respectively. The frequency and duration of HFC differed by age, economic activity and household income.

CONCLUSIONS

HFC was highest at the nose in Korean older people, followed by the mouth. Consequently, education about avoiding HFC of the nose and hygienic care of the nose should be a nursing priority. Awareness of the risks of HFC and the prophylactic effects of vigorous hand hygiene should be strengthened among the elderly to prevent the spread of infectious diseases via hand contact.

Prevalence of human cystic echinococcosis in the towns of Ñorquinco and Ramos Mexia in Rio Negro Province, Argentina, and direct risk factors for infection

Background

Cystic echinococcosis (CE) is a parasitic zoonosis caused by infection with the larval stage of Echinococcus granulosus (s.l.). This study investigated the prevalence and potential risk factors associated with human CE in the towns and rural areas of Ñorquinco and Ramos Mexia, Rio Negro province, Argentina.

Methods

To detect abdominal CE cysts, we screened 892 volunteers by ultrasound and investigated potential risk factors for CE using a standardized questionnaire. Prevalence ratio (PR) with 95% confidence intervals (CI) was used to measure the association between CE and the factors investigated, applying bivariate and multivariate analyses.

Results

Abdominal CE was detected in 42/892 screened volunteers (4.7%, 95% CI 3.2–6.1), only two of whom were under 15 years of age. Thirteen (30.9%) CE cases had 25 cysts in active stages (CE1, CE2, CE3a, according to the WHO Informal Working Group on Echinococcosis [WHO-IWGE] classification). The most relevant risk factors identified in the bivariate analysis included: living in rural areas (P = 0.003), age > 40 years (P = 0.000), always drinking water from natural sources (P = 0.007), residing in rural areas during the first 5 years of life (P = 0.000) and having lived more than 20 years at the current address (P = 0.013). In the multivariate final model, the statistically significant risk factors were: frequently touching dogs (P = 0.012), residing in rural areas during the first 5 years of life (P = 0.004), smoking (P = 0.000), age > 60 years (P = 0.002) and living in rural areas (P = 0.017).

Conclusions

Our results point toward infection with CE being acquired since childhood and with constant exposure throughout life, especially in rural areas with a general environmental contamination.

Graphic Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04753-y.

Hand-to-face contact behaviors during indoor activities in daily life among Korean adults: an observational pilot study using videotaping

OBJECTIVES

Hand-to-face contact (HFC) is the major route for the self-inoculation of pathogens. This study aimed to describe the characteristics of HFC behaviors among Korean adults during indoor activities.

METHODS

Thirty participants were enrolled in the study, and 2 hours of videotaped data were collected from each participant. Contact data were recorded by examining the frequency and duration of HFC on the videos. Three training sessions were conducted for 2 readers to ensure the accuracy and reliability of videotape reading. Re-reading and verification of selected video data were performed to confirm intrapersonal and interpersonal validity. Contact exposure (CE) was determined by multiplying the contact frequency (CF) by the contact duration (CD) to quantify the intensity of contact during the observation time (2 hours).

RESULTS

A total of 3,007 HFCs (1,305 mucous membrane contacts and 1,702 non-mucous membrane contacts) were observed for 60 person-hours. The median CF (person/2 hr) of the mucous membranes (eye; 4.0, nose; 15.5, mouth; 16.5) was 39.5/person and the median total CD was 177.0 sec/person. The median CE (frequency-duration/sec/person) was 5,795.0 (mouth: 1,356.0, nose: 600.0, eye: 57.5).

CONCLUSIONS

This study showed that the mouth and nose were the most frequent exposure sites for HFC. Avoiding habitual HFC, awareness of self-inoculation by HFC, and vigorous hand hygiene should be strengthened to prevent the spread of infections.

A Case Study of Brass Foundry Workers' Estimated Lead (Pb) Body Burden from Different Exposure Routes

Objectives

The most pronounced occupational exposure routes for lead (Pb) are inhalation and gastrointestinal uptake mainly through hand-to-mouth behaviour. Skin absorption has been demonstrated for organic Pb compounds, but less is known about inorganic Pb species. Several legislative bodies in Europe are currently proposing lowering biological exposure limit values and air exposure limits due to new evidence on cardiovascular effects at very low blood Pb levels. In light of this, all exposure routes in occupational settings should be revisited to evaluate how to lower the overall exposure to Pb.

Methods

The aim of the study was to investigate the possible exposure routes in workers operating computer numerical control-machines in a brass foundry and specifically to understand if metal cutting fluids (MCFs) used by the workers could lead to skin absorption of Pb. The different bronze alloys at the facility may contain up to 20% Pb. After obtaining written informed consent from the workers (n = 7), blood, skin wipes, and personal air samples were collected. In addition, MCFs used on the day of exposure measurements were collected for in vitro skin absorption studies using stillborn piglet skin mounted in static Franz diffusion cells (n = 48). All samples were analysed for Pb content using inductively coupled plasma mass spectrometry.

Results

Pb air concentration (<0.1–3.4 µg m⁻³) was well below the Swedish occupational exposure limit value. Blood Pb was in the range of <0.72–33 µg dl⁻¹, and Pb on skin surfaces, after performing normal work tasks during 2 h, was in the range of 0.2–48 µg cm⁻². Using the MCFs in diffusion cells showed that skin absorption had occurred at very low doses, and that up to 10% of the Pb content was present in the skin after 24 h exposure. Using these results in the US EPA adult lead model, we could estimate a contribution to blood Pb from the three exposure routes; where hand-to-mouth behaviour yielded the highest contribution (16 µg Pb dl⁻¹ blood), followed by skin absorption (3.3–6.3 µg Pb dl⁻¹ blood) and inhalation (2.0 µg Pb dl⁻¹ blood).

Conclusions

This case study shows that MCF may lead to skin absorption of inorganic Pb and contribute to a systemic dose (quasi-steady state). Furthermore, even though good hand hygienic measures were in place, the workers’ skin exposure to Pb is in all likelihood an important contributor in elevating blood Pb levels. Skin exposure should thus be monitored routinely in workers at facilities handling Pb, to help reducing unnecessary occupational exposure.

Hand-to-mouth and other hand-to-face touching behavior in a quasi-naturalistic study under controlled conditions

Data gaps exist in our understanding of hand-to-mouth touching behavior among adults, despite its relevance for accurately characterizing inadvertent ingestion exposures to chemical and pathogenic microbial agents and consequent associated health risks. The present study describes detailed observations of the frequency and nature of hand-to-mouth and other hand-to-face touching behavior among 14 male and female volunteers in a controlled, quasi-naturalistic setting. Participants performed four 15-min tasks: 1) installation of a brass object as part of a short home improvement project, 2) completion of a pen-and-paper survey, 3) engagement in a telephone conversation, and 4) use of headphones to listen to music. Video recordings of the participants performing each task were reviewed and coded for touches to the face with emphasis on specific regions of the face and palmar versus dorsal contacts. During the installation task, only one of the 14 participants was observed touching his face; this was to the nose, on two separate occasions. Summed across the three non-installation tasks, including palmar and dorsal contacts, participants touched their lips, their mouth, and anywhere on their face on average (range) 5.1 (0-19), 0.4 (0-3), and 27.7 (6-49) times, respectively. Facial contacts during these three non-installation tasks were predominantly with the palmar surface of the hand. The implications of these data are contextually specific, as the potential health impacts of face touching behavior among adults might differ based upon toxicity or virulence of hand contaminants of interest.

Assessment of Occupational Exposure to Organic Flame Retardants: A Systematic Review

BACKGROUND

Flame retardants (FRs) are widespread in common goods, and workers in some industries can be exposed to high concentrations. Numerous studies describe occupational exposure to FRs, but the diversity of methods and of reported results renders their interpretation difficult for researchers, occupational hygienists, and decision makers.

OBJECTIVES

The objectives of this paper are to compile and summarize the scientific knowledge on occupational exposure to FRs as well as to identify research gaps and to formulate recommendations.

METHODS

Five databases were consulted for this systematic literature review (Embase, Medline [Pubmed], Global health, Web of Science, and Google Scholar), with terms related to occupational exposure and to FRs. Selected studies report quantitative measurements of exposure to organic FRs in a workplace, either in air, dust, or in workers' biological fluids. The Preferred Reporting Items for Systematic reviews and Meta-Analyses statement guidelines were followed.

RESULTS

The search yielded 1540 published articles, of which 58 were retained. The most frequently sampled FRs were polybrominated diphenyl ethers and novel brominated FRs. Offices and electronic waste recycling facilities were the most studied occupational settings, and the highest reported exposures were found in the latter, as well as in manufacturing of printed circuit boards, in aircrafts, and in firefighters. There were recurrent methodological issues, such as unstandardized and ill-described air and dust sampling, as well as deficient statistical analyses.

CONCLUSIONS

This review offers several recommendations. Workplaces such as electronic waste recycling or manufacturing of electronics as well as firefighters and aircraft personnel should be granted more attention from researchers and industrial hygienists. Methodical and standardized occupational exposure assessment approaches should be employed, and data analysis and reporting should be more systematic. Finally, more research is needed on newer chemical classes of FRs, on occupational exposure pathways, and on airborne FR particle distribution.

Reinventing the Wheel of Echinococcus granulosus sensu lato Transmission to Humans

Control of cystic echinococcosis (CE) relies on interrupting Echinococcus granulosus sensu lato transmission through interventions in dogs and livestock. However, primary prevention measures aimed at avoiding ingestion of Echinococcus eggs may help reduce the burden of human CE. CE is generally considered, to variable extents, to be foodborne, but there is little evidence on the actual contamination of matrices and sociocultural factors involved in parasite transmission. An overall appraisal of published literature suggests that environmental contamination, possibly through hand-to-mouth transmission, may be of primary importance. While in most endemic areas sufficient epidemiological information is available to start CE control programs, identifying the main sources of infection to humans would allow optimization of site-specific interventions while avoiding irrelevant health education messages.

Controlling the risks of nano-enabled products through the life cycle: The case of nano copper oxide paint for wood protection and nano-pigments used in the automotive industry

The widespread use of engineered nanomaterials (ENMs) in consumer products and the overwhelming uncertainties in their ecological and human health risks have raised concerns regarding their safety among industries and regulators. There has been an ongoing debate over the past few decades on ways to overcome the challenges in assessing and mitigating nano-related risks, which has reached a phase of general consensus that nanotechnology innovation should be accompanied by the application of the precautionary principle and best practice risk management, even if the risk assessment uncertainties are large. We propose a quantitative methodology for selecting the optimal risk control strategy based on information about human health and ecological risks, efficacy of risk mitigation measures, cost and other contextual factors. The risk control (RC) methodology was developed in the European FP7 research project SUN and successfully demonstrated in two case studies involving real industrial nano-enabled products (NEPs): nano-scale copper oxide (CuO) and basic copper carbonate (Cu₂(OH)₂CO₃) used as antimicrobial and antifungal coatings and impregnations for the preservation of treated wood, and two nanoscale pigments used for colouring plastic automotive parts (i.e. red organic pigment and carbon black). The application of RC for human health risks showed that although nano-related risks could easily be controlled in automotive plastics case study with modifications in production technology or specific type of engineering controls, nano-related risks due to sanding and sawing copper oxide painted wood were non-acceptable in the use lifecycle stage and would need the identification of a more effective risk control strategy.

Evaluating Glyphosate Exposure Routes and Their Contribution to Total Body Burden: A Study Among Amenity Horticulturalists

OBJECTIVE

To evaluate determinants of dermal and inadvertent ingestion exposure and assess their contribution to total body burden among amenity horticultural users using glyphosate-based pesticide products.

METHODS

A dermal and inadvertent ingestion exposure assessment was completed alongside a biomonitoring study among amenity horticultural workers. Linear mixed effect regression models were elaborated to evaluate determinants of exposure and their contribution to total body burden.

RESULTS

A total of 343 wipe and glove samples were collected from 20 workers across 29 work tasks. Geometric mean (GM) glyphosate concentrations of 0.01, 0.04 and 0.05 µg cm-2 were obtained on wipes from the workers' perioral region and left and right hands, respectively. For disposable and reusable gloves, respectively, GM glyphosate concentrations of 0.43 and 7.99 µg cm-2 were detected. The combined hand and perioral region glyphosate concentrations explained 40% of the variance in the urinary (µg l-1) biomonitoring data.

CONCLUSION

To the author's knowledge, this is the first study to have investigated both dermal and inadvertent exposure to glyphosate and their contribution to total body burden. Data show the dermal exposure is the prominent route of exposure in comparison to inadvertent ingestion but inadvertent ingestion may contribute to overall body burden. The study also identified potential exposure to non-pesticide users in the workplace and para-occupational exposures.

Field Measurements of Inadvertent Ingestion Exposure to Metals

The determinants of inadvertent occupational ingestion exposure are poorly understood, largely due to a lack of available exposure measurement data. In this study, perioral exposure wipes were used as a surrogate for inadvertent ingestion exposure to measure exposure to eight metals (chromium, nickel, aluminium, cobalt, lead, arsenic, manganese, and tin) among 38 workers at 5 work sites in the UK. This work was done alongside a previously reported observational study of hand/object-to-mouth contact frequency. Systematic wipes of the perioral area, and of both hands were taken with proprietary cellulose wipes pre-moistened with deionized water. Measurements were taken at the beginning, middle and end of the shift. Mixed-effect models of exposure measurements were built with area of skin sampled, time during shift, and job group entered as fixed effects and worker identification as a random effect. Linear regression modelling was used to study the effect of hand/object-to-mouth contact frequency on perioral exposure, adjusting for the measured exposure on the hand and observed respirator use. Hand and perioral exposure measurements were correlated with one another (r = 0.79) but mass per unit area exposure was significantly higher on the perioral area than on the hands for seven of the metals (at P < 0.05). There were no significant differences between measurements taken at the middle or the end of the shift for five of the metals suggesting that dermal loading may remain relatively constant for much of the workday. This applies to both hand and perioral measurements. In linear regression modelling there was no relationship between hand/object-to-mouth contact frequency and perioral exposure, but hand exposure was significantly positively related to perioral exposure and workers who used respirators had significantly higher perioral exposure than those who did not. The results suggest the levels of exposure on the hand and respirator use are important determinants of potential inadvertent ingestion exposure. The results did not demonstrate a relationship between perioral exposure and hand-to-mouth contact frequency. Perioral wipe sampling may be a useful surrogate measure for exposure by the inadvertent ingestion route, but further research is required to confirm the link between perioral levels and actual exposure, measured using biological monitoring.

Annual Burden of Occupationally-Acquired Influenza Infections in Hospitals and Emergency Departments in the United States

Infections among health-care personnel (HCP) occur as a result of providing care to patients with infectious diseases, but surveillance is limited to a few diseases. The objective of this study is to determine the annual number of influenza infections acquired by HCP as a result of occupational exposures to influenza patients in hospitals and emergency departments (EDs) in the United States. A risk analysis approach was taken. A compartmental model was used to estimate the influenza dose received in a single exposure, and a dose-response function applied to calculate the probability of infection. A three-step algorithm tabulated the total number of influenza infections based on: the total number of occupational exposures (tabulated in previous work), the total number of HCP with occupational exposures, and the probability of infection in an occupational exposure. Estimated influenza infections were highly dependent upon the dose-response function. Given current compliance with infection control precautions, we estimated 151,300 and 34,150 influenza infections annually with two dose-response functions (annual incidence proportions of 9.3% and 2.1%, respectively). Greater reductions in infectious were achieved by full compliance with vaccination and IC precautions than with patient isolation. The burden of occupationally-acquired influenza among HCP in hospitals and EDs in the United States is not trivial, and can be reduced through improved compliance with vaccination and preventive measures, including engineering and administrative controls.

Occupational dermal exposure to nanoparticles and nano-enabled products: Part 2, exploration of exposure processes and methods of assessment

Over the past decade, the primary focus of nanotoxicology and nanoenvironmental health and safety efforts has been largely on inhalation exposure to engineered nanomaterials, at the production stage, and much less on considering risks along the life cycle of nano-enabled products. Dermal exposure to nanomaterials and its health impact has been studied to a much lesser extent, and mostly in the context of intentional exposure to nano-enabled products such as in nanomedicine, cosmetics and personal care products. How concerning is dermal exposure to such nanoparticles in the context of occupational exposures? When and how should we measure it? In the first of a series of two papers (Larese Filon et al., 2016), we focused our attention on identifying conditions or situations, i.e. a combination of nanoparticle physico-chemical properties, skin barrier integrity, and occupations with high prevalence of skin disease, which deserve further investigation. This second paper focuses on the broad question of dermal exposure assessment to nanoparticles and attempts to give an overview of the mechanisms of occupational dermal exposure to nanoparticles and nano-enabled products and explores feasibility and adequacy of various methods of quantifying dermal exposure to NOAA. We provide here a conceptual framework for screening, prioritization, and assessment of dermal exposure to NOAA in occupational settings, and integrate it into a proposed framework for risk assessment.