Accuracy of a semiquantitative method for Dermal Exposure Assessment (DREAM).

BACKGROUND: The authors recently developed a Dermal Exposure Assessment Method (DREAM), an observational semiquantitative method to assess dermal exposures by systematically evaluating exposure determinants using pre-assigned default values. AIM: To explore the accuracy of the DREAM method by comparing its estimates with quantitative dermal exposure measurements in several occupational settings. METHODS: Occupational hygienists observed workers performing a certain task, whose exposure to chemical agents on skin or clothing was measured quantitatively simultaneously, and filled in the DREAM questionnaire. DREAM estimates were compared with measurement data by estimating Spearman correlation coefficients for each task and for individual observations. In addition, mixed linear regression models were used to study the effect of DREAM estimates on the variability in measured exposures between tasks, between workers, and from day to day. RESULTS: For skin exposures, spearman correlation coefficients for individual observations ranged from 0.19 to 0.82. DREAM estimates for exposure levels on hands and forearms showed a fixed effect between and within surveys, explaining mainly between-task variance. In general, exposure levels on clothing layer were only predicted in a meaningful way by detailed DREAM estimates, which comprised detailed information on the concentration of the agent in the formulation to which exposure occurred. CONCLUSIONS: The authors expect that the DREAM method can be successfully applied for semiquantitative dermal exposure assessment in epidemiological and occupational hygiene surveys of groups of workers with considerable contrast in dermal exposure levels (variability between groups >1.0). For surveys with less contrasting exposure levels, quantitative dermal exposure measurements are preferable.

An assessment of dermal exposure to semi-synthetic metal working fluids by different methods to group workers for an epidemiological study on dermatitis.

BACKGROUND: Assessment of exposure assessment to metal working fluids (MWF) has almost exclusively focused on inhalation exposure. AIMS: To assess levels of, and factors affecting, dermal and inhalation exposure to semi-synthetic MWF, and to identify suitable dermal exposure grouping schemes among metal workers for an epidemiological survey on dermatitis of hands, forearms, and head. METHODS: A cross-sectional survey was conducted in four metal working machining departments of a truck manufacturing plant, estimating dermal and inhalation exposure levels to semi-synthetic metal working fluids (SMWF) in machine operators. Dermal exposure levels to SMWF were estimated by three different methods for dermal exposure assessment (VITAE, surrogate skin pad method, and a semi-quantitative dermal exposure assessment method (DREAM)). RESULTS: The identified factors affecting dermal exposure were similar for the three methods, although differences were found for estimated variability in dermal exposure levels between groups, within groups (among workers), and from day to day. With the VITAE method differences in exposure levels were detected between workers that were not detected with the surrogate skin pad method, and only partly with the DREAM method. CONCLUSIONS: Considering the additional effort and costs that use of the VITAE method entailed, the observational semi-quantitative DREAM method appeared to be more efficient for grouping of dermal exposure levels for the epidemiological study on dermatitis.

Pesticide-related illness and injuries among banana workers in Costa Rica: a comparison between 1993 and 1996.

An intervention program considerably decreased systemic poisonings on banana plantations in Costa Rica in the early 1990s. Nevertheless, pesticide safety continues to be controversial. To examine the determinants of acute pesticide-related illness on banana plantations, the authors surveyed occupational injuries and illness among banana workers in the Atlantic Region of Costa Rica that were reported during 1993 and 1996 to the National Insurance Institute. Incidence rates were calculated for categories of pesticides and types of medical problems, for all and subgroups of banana workers. Between 1993 and 1996, an overall 35% decrease in injuries was observed, attributable to a marked decline in topical injuries (3.3 vs 1.9 per 100 workers), whereas systemic poisonings remained the same (0.7 per 100 in both years). The decrease concerned selectively milder skin conditions, indicating underreporting of less severe health effects. In both years, paraquat was the pesticide most frequently associated with injuries, mostly skin and eye lesions. Workers at highest risk per unit time of exposure were nematocide applicators, herbicide applicators, and cleaners of packing plants. Despite control measures, further reduction of systemic illness had not been achieved. The decrease of topical injuries may be partly explained by improved work conditions, but possible underreporting hinders interpretation. Pesticide-related illness on banana plantations is a persistent problem.

Chronic nervous-system effects of long-term occupational exposure to DDT.

Dichlorodiphenyltrichloroethane (DDT) is a compound with moderate toxicity that is judged to be safe for occupational use, although little is known about its long-term effects on the human nervous system. We investigated chronic nervous-system effects of long-term occupational exposure to DDT by comparing the neurobehavioural performance of retired malaria-control workers with a reference group of retired guards and drivers. DDT-exposed workers did worse on tests assessing various neurobehavioural functions than controls; performance significantly deteriorated with increasing years of DDT application. Our results could not be explained by exposure to cholinesterase-inhibiting pesticides or other potential confounding factors.

Paraquat in developing countries.

The herbicide paraquat is considered safe by industry and the bulk of regulators worldwide. However, determinants of exposure from 30 years ago persist in developing countries. Little is known about systemic absorption from occupational exposures. The relationships between exposure determinants, levels of external exposure, biomarkers of exposure, and outcomes are not clear. High rates of severe acute poisonings have been documented. In addition, topical injuries occur in as many as 50% of exposed workers. Non-worker populations are also at risk, particularly children. Long-term and delayed health effects include Parkinson's disease, lung effects, and skin cancer. Regulatory agencies have not fully recognized either the inherent toxicity of paraquat or the particular risks derived from exposures in developing countries. Independent risk assessment in the developing-country context and application of the precautionary principle are necessary to prevent adverse effects of dangerous pesticides in susceptible populations.

Hazardous pesticides in Central America.

Pesticides are an extensively documented occupational and environmental hazard in Central America. Yet, severe problems persist. Toxic pesticide use in the Region increased during 1985-1999. High exposure levels and ineffectiveness of personal protective equipment evidence the difficulties for risk reduction. Acute poisonings remain a severe problem. Delayed and/or long-lasting health effects include dermatoses, cancer, and genotoxic, neurotoxic, and respiratory effects. The use of hazardous pesticides persists through deficiencies in government-driven assessment and risk management; excessive focus on regional harmonization; short-term economic interests; strong links between industry and governments; aggressive marketing; weak trade unions; and failure of universities to reach decision makers. Regulation based on local data is lacking. An agreement of the Ministries of Health for restricting the most toxic pesticides in Central America has potential for progress. The most effective way to reduce risk is to greatly reduce pesticide use. Actions needed include development of multidisciplinary strategies for local studies on health and environmental impact of pesticides; development of sustainable nonchemical agricultural technologies; evaluation of interventions; extending and sharing of expertise within the Region; strengthening of unions and communities; and redefining the role of industry toward development of safer products, with responsible marketing and reliable information.

Physical load in ship maintenance: hazard evaluation by means of a workplace survey.

In a population of male workers in two ship maintenance companies (n = 32), a workplace survey was conducted in order to quantify their physical load. Postural load was measured by using the Ovako Working posture Analyzing System. During 7480 observations, working postures, exertion of force and working activities were recorded. Awkward postures of the back occurred in 38% of the worktime, stress on the neck/shoulder region due to one or both arms above shoulder level was present in 25% of the worktime. Forceful exertions during lifting, pushing and pulling activities sometimes exceeded published guidelines for manual material handling. Determinants of physical load could be identified and a hazard evaluation procedure was designed by applying rating schemes to weight various patterns of physical load. Ship maintenance work compared well with other strenuous occupations. Considering the high prevalence of back pain (80%) and neck/shoulder pain (60%), as well as the results of the observation method ergonomic improvements are warranted. Physical load can be reduced by several technical adaptations and applications, and by enlarging task rotation.