Christine Northage

Exposure scenarios for workers.

The new European chemicals legislation REACH (Registration, Evaluation, Authorisation and restriction of Chemicals) requires the development of Exposure Scenarios describing the conditions and risk management measures needed for the safe use of chemicals. Such Exposure Scenarios should integrate considerations of both human health and the environment. Specific aspects are relevant for worker exposure. Gathering information on the uses of the chemical is an important step in developing an Exposure Scenario. In-house information at manufacturers is an important source. Downstream users can contribute information through direct contact or through their associations. Relatively simple approaches (Tier 1 tools, such as the ECETOC Targeted Risk Assessment and the model EASE) can be used to develop broad Exposure Scenarios that cover many use situations. These approaches rely on the categorisation of just a few determinants, including only a small number of risk management measures. Such approaches have a limited discriminatory power and are rather conservative. When the hazard of the substance or the complexity of the exposure situation require a more in-depth approach, further development of the Exposure Scenarios with Tier 2 approaches is needed. Measured data sets of worker exposure are very valuable in a Tier 2 approach. Some downstream user associations have attempted to build Exposure Scenarios based on measured data sets. Generic Tier 2 tools for developing Exposure Scenarios do not exist yet. To enable efficient development of the worker exposure part of Exposure Scenarios a further development of Tier 1 and Tier 2 tools is needed. Special attention should be given to user friendliness and to the validity (boundaries) of the approaches. The development of standard worker exposure descriptions or full Exposure Scenarios by downstream user branches in cooperation with manufacturers and importers is recommended.

Measurement of short-term exposure to airborne soluble platinum in the platinum industry

A number of cases of respiratory sensitization to soluble platinum have arisen in the U.K. over the last few years, despite measured 8 h TWA exposure levels below the current long-term exposure limit in most cases. One possible cause of sensitization may be as a result of high exposures over short periods. Short-term sampling has been hampered by inadequate sampling and analysis techniques. This investigation has used two types of personal inhalable sampler, with ICPMS analysis, to take 15 min TWA soluble platinum exposure measurements at three sites. The lower detection limit for soluble platinum salts was approximately 0.01 microgram m-3 for 15 min samples, allowing exposures two orders of magnitude below the exposure limit to be measured. It was found that the majority of short-term exposure levels were significantly below 0.006 mg m-3. No evidence was found for altered work practices during sampling, indicating that either sensitization is occurring at airborne exposure levels below the exposure limit, or there is an alternate route of exposure.

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. The work described in this manuscript has been carried out as part of a project to develop a predictive model for estimating inadvertent ingestion exposure in the workplace. As inadvertent ingestion exposure mainly arises from hand-to-mouth contact, it is closely linked to dermal exposure. We present a new integrated conceptual model for dermal and inadvertent ingestion exposure that should help to increase our understanding of ingestion exposure and our ability to simultaneously estimate exposure by the dermal and ingestion routes. The conceptual model consists of eight compartments (source, air, surface contaminant layer, outer clothing contaminant layer, inner clothing contaminant layer, hands and arms layer, perioral layer, and oral cavity) and nine mass transport processes (emission, deposition, resuspension or evaporation, transfer, removal, redistribution, decontamination, penetration and/or permeation, and swallowing) that describe event-based movement of substances between compartments (e.g. emission, deposition, etc.). This conceptual model is intended to guide the development of predictive exposure models that estimate exposure from both the dermal and the inadvertent ingestion pathways. For exposure by these pathways the efficiency of transfer of materials between compartments (for example from surfaces to hands, or from hands to the mouth) are important determinants of exposure. A database of transfer efficiency data relevant for dermal and inadvertent ingestion exposure was developed, containing 534 empirically measured transfer efficiencies measured between 1980 and 2010 and reported in the peer-reviewed and grey literature. The majority of the reported transfer efficiencies (84%) relate to transfer between surfaces and hands, but the database also includes efficiencies for other transfer scenarios, including surface-to-glove, hand-to-mouth, and skin-to-skin. While the conceptual model can provide a framework for a predictive exposure assessment model, the database provides detailed information on transfer efficiencies between the various compartments. Together, the conceptual model and the database provide a basis for the development of a quantitative tool to estimate inadvertent ingestion exposure in the workplace.

Workplace Exposure to Rosin-based Solder Flux Fume During Hand Soldering

The patterns and extent of exposure to rosin based solder flux fume have been investigated in two surveys and a number of individual site visits carried out by the UK Health and Safety Executive (HSE). Determination of solder fume was by measurement of airborne resin acid particulate. Both static and personal sampling was carried out over time periods ranging from 15 minutes to several hours. Resin acid concentrations were found to vary from less than 1 microgram m-3 to 2289 micrograms m-3. The effects of various types of local exhaust ventilation on resin acid concentrations have been observed. On-tool tip extraction systems were generally found to be the best control measure available; however good design, positioning and system maintenance is essential for efficient capture of the fume. The resin acid concentrations detected at these twenty-six sites suggest that the proposed British long and short term occupational exposure limits are realistically attainable targets, particularly where good working practices and/or effective fume control measures are in place.

An Investigation of Short-Term Gravimetric Sampling in Pig Farms and Bakeries

Abstract Exposure to some workplace dusts can lead to occupational asthma through respiratory sensitization. It is thought that sensitization may be related to high exposures of short duration, thus requiring short-term exposure monitoring. In the United Kingdom there are presently no guidelines for taking short-term (15-minute) gravimetric samples. This investigation has evaluated the use of IOM and CIP 10 personal inhalable samplers for taking short-term samples in a series of field trials carried out in bakeries and pig farms. A direct-reading dust monitor (MIE Miniram) has also been used to provide time-resolved dust concentration levels. Uncertainties in measurements were dominated by the weight stability of the sample collection media used. The lower detection limits for the short-term samples were typically estimated at 3 mg m-3 for the IOM sampler using a metal cassette, and 1.8 mg m-3 with the CIP 10 sampler. IOM short-term samples were generally higher than concurrent CIP 10 short-term samples a...

An investigation into the composition of products evolved during heating of hot melt adhesives.

The major chemical components generated by a selection of fourteen hot melt adhesives during heating have been identified. This information is required so that the possible health consequences of occupational exposure can be assessed and advice on controls developed. Details are also given of the test apparatus and standard testing procedure devised for this investigation. Analysis of the evolved material indicates the presence of a wide range of chemical compounds, including resin acids, volatile terpenes, aliphatic aldehydes, aliphatic and aromatic hydrocarbons and isocyanates. Some components, including resin acids and formaldehyde, are common to several types of adhesive, whereas others, such as acrolein and isocyanates, are specific to just one. There is no component which is characteristic of fume from all fourteen adhesives. Concentrations of individual chemical components show significant variation, both between different types of adhesive, and between samples of the same adhesive heated to different temperatures or for different periods of time. For individual adhesives, concentrations of evolved material tend to increase as the temperature of the glue is raised, with the highest levels being observed in samples taken directly after commencement of heating.