Recent trends in respirable crystalline silica and elemental carbon exposure in the Ontario, Canada mining industry.

Introduction: Mining is a high-hazard industry with significant occupational disease risks. Despite this there is limited data describing current exposure conditions. The aim of this short communication is to share recent exposure data from underground mines in Ontario, Canada.

Determinants of respirable crystalline silica exposure in construction in western Canada.

Task-based respirable crystalline silica (RCS) exposure monitoring data was collected from construction work sites across 3 Canadian provinces: Alberta, British Columbia (BC), and Manitoba. In total 373 RCS samples were obtained from 70 worksites across 44 companies. Sampling was conducted between May 2015 and August 2020.

Assessing Exposures from the Deepwater Horizon Oil Spill Response and Clean-up.

The GuLF Study is investigating adverse health effects from work on the response and clean-up after the Deepwater Horizon explosion and oil release. An essential and necessary component of that study was the exposure assessment. Bayesian statistical methods and over 135 000 measurements of total hydrocarbons (THC), benzene, ethylbenzene, toluene, xylene, and n-hexane (BTEX-H) were used to estimate inhalation exposures to these chemicals for >3400 exposure groups (EGs) formed from three exposure determinants: job/activity/task, location, and time period.

Estimation of Dermal Exposure to Oil Spill Response and Clean-up Workers after the Deepwater Horizon Disaster.

The GuLF STUDY is investigating health outcomes associated with oil spill-related chemical exposures among workers involved in the spill response and clean-up following the Deepwater Horizon disaster. Due to the lack of dermal exposure measurements, we estimated dermal exposures using a deterministic model, which we customized from a previously published model. Workers provided information on the frequency of contact with oil, tar, chemical dispersants applied to the oil spill and sea water, as well as the use of protective equipment, by job/activity/task.

Diesel Engine Exhaust Exposure in the Ontario Civil Infrastructure Construction Industry.

Objectives: Diesel engine exhaust (DEE) is a known lung carcinogen and a common occupational exposure in Canada. The use of diesel-powered equipment in the construction industry is particularly widespread, but little is known about DEE exposures in this work setting. The objective of this study was to determine exposure levels and identify and characterize key determinants of DEE exposure at construction sites in Ontario.

Development of a Web-Based Tool for Risk Assessment and Exposure Control Planning of Silica-Producing Tasks in the Construction Sector.

We describe the development and implementation of a novel, on-line risk assessment tool for respirable crystalline silica (RCS) exposure for use in the construction sector. It was motivated by the introduction of new OHS regulation in British Columbia that allowed for the substitution of exposure measurement data with "objective air monitoring data" collected at "equivalent work operations." This allowance encouraged the introduction of quantitative risk assessment in a notoriously challenging work environment but it was concluded that without assistance, the typical construction employer would struggle to identify, extract, and interpret validate objective data.

GuLF DREAM: A Model to Estimate Dermal Exposure Among Oil Spill Response and Clean-up Workers.

Tens of thousands of individuals performed oil spill response and clean-up (OSRC) activities following the 'Deepwater Horizon' oil drilling rig explosion in 2010. Many were exposed to oil residues and dispersants. The US National Institute of Environmental Health Sciences assembled a cohort of nearly 33 000 workers to investigate potential adverse health effects of oil spill 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.

A Web-based Tool to Aid the Identification of Chemicals Potentially Posing a Health Risk through Percutaneous Exposure.

Occupational hygiene practitioners typically assess the risk posed by occupational exposure by comparing exposure measurements to regulatory occupational exposure limits (OELs). In most jurisdictions, OELs are only available for exposure by the inhalation pathway. Skin notations are used to indicate substances for which dermal exposure may lead to health effects.

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

Contact between contaminated hands and the mouth or the area around the mouth (the perioral area) can result in inadvertent ingestion exposure. Exposure by this route is known to occur among children, but adults may also be exposed. Observations of 48 workers were carried out in 8 UK worksites to study hand- and object-to-mouth behavior.

Simulated transfer of liquids and powders from hands and clothing to the mouth.

A series of laboratory experiments was carried out to assess transfer of liquids (vinegar) and powders (calcium acetate and magnesium carbonate) from hands, arms, gloves, respirators, clothing, and pens to the oral cavity or the perioral area (the area surrounding the mouth). Experiments were carried out with four volunteers. The donor area (the hands, arms, gloves, and so on) was loaded with a known mass of the test substance and was then brought into contact the receiver area (the oral cavity or the perioral area).

A preliminary comparison of three dermal exposure sampling methods: rinses, wipes and cotton gloves.

Several methods exist to estimate dermal exposure and it is unclear how comparable they are. These methods fall into three main categories: (i) removal techniques (such as wiping or rinsing); (ii) interception techniques (such as gloves, patches, or coveralls); and (iii) fluorescent tracer techniques. Controlled experiments were conducted to compare two removal methods for exposure to particulate, and a removal method with an interception method for exposure to liquids.

Properties of liquids and dusts: how do they influence dermal loading during immersion, deposition, and surface contact exposure pathways?

Background: Although dustiness and viscosity are potential determinants of dermal exposure, their effect on exposure is poorly understood. The goal of this study was to investigate the effect of dustiness and viscosity on dermal exposure by each of three dermal exposure pathways (deposition, surface contact, and immersion).

Methods: The hands of four volunteers were exposed to non-toxic substances: particulate with varying dustiness (calcium acetate, zinc oxide, and Epsom salt) and liquids of varying viscosity (three glycerol/water solutions containing 20, 50, or 85% glycerol) by each pathway.

Fertilizer use and self-reported respiratory and dermal symptoms among tree planters.

In British Columbia, some tree planting operations require workers to fertilize planted seedlings with polymer-coated nitrogen, phosphorus, and potassium (NPK) fertilizers. This study examined respiratory and dermal health associated with fertilizer exposure among tree planters. We interviewed 223 tree planters using an adapted version of the American Thoracic Society questionnaire supplemented with questions on dermal health.

The relationship between inadvertent ingestion and dermal exposure pathways: a new integrated conceptual model and a database of dermal and oral transfer efficiencies.

Occupational inadvertent ingestion exposure is ingestion exposure due to contact between the mouth and contaminated hands or objects. Although individuals are typically oblivious to their exposure by this route, it is a potentially significant source of occupational exposure for some substances. Due to the continual flux of saliva through the oral cavity and the non-specificity of biological monitoring to routes of exposure, direct measurement of exposure by the inadvertent ingestion route is challenging; predictive models may be required to assess exposure.

Exposure to pesticides and metal contaminants of fertilizer among tree planters.

In British Columbia, Canada, harvested forests are manually replanted by seasonal workers. The work is known to be physically demanding and ergonomically difficult, and recently, there have been concerns over chemical exposures due to pesticide residues on seedlings, fertilizers (often applied alongside seedlings), and potential metal contamination of these fertilizers. This study aimed to characterize metal and pesticide exposure among a sample of British Columbia tree planters.