Yant Memorial Award Lecture, 1992. A more informative list of occupational exposure limits with a supplement.

Dr. Reinier Zielhuis was presented with the Yant Memorial Award by the American Industrial Hygiene Association in 1992. The award recognizes outstanding contributions in industrial hygiene or allied fields made by an individual residing outside the United States. Dr. Zielhuis was chair of occupational and environmental health, medical faculty, at Coronel Laboratory of the University of Amsterdam from 1964-1987. Since 1987 he has been advisor to the Department of Toxic Substances of the Dutch Directorate-General of Labour. In 1990-1991 he was also advisor to the European Community on occupational standard setting. For personal reasons Dr. Zielhuis was unable to present the Memorial Award Lecture at the 1992 American Industrial Hygiene Conference & Exposition, but prepared the following article for publication in the Journal.

Medical wastage in shipyard welders: a forty-year historical cohort study.

A 40-year historical cohort study of medical wastage among about 550 shipyard welders and 1100 controls (shipwrights and engine fitters), all employed at the same shipyard, was carried out. The welders left their job 20% more often than the controls; the excess considerably increased with duration of employment. Wastage was particularly due to respiratory, cardiovascular, locomotor and mental disorders. Both welders and controls contributed considerably (about 20%) to permanent work disability. Medical wastage among welders because of respiratory diseases was more than four times higher than among controls, which could not be explained by differential smoking habits alone. The study raises concern about locomotor health hazards for shipyard workers. Moreover, it underscores the need to reduce the large excess risk of respiratory diseases among shipyard welders. The same may be true for welders in other large metal construction plants, e.g. in boiler production.

Harmonization of criteria documents for standard setting in occupational health: a report of a workshop.

The paper presents the most important points of the discussion, recommendations, and conclusions of a workshop on harmonization of criteria documents (CDs) for standard setting in occupational health, with emphasis on standard setting in the European Community (EC). The objectives were to achieve harmonized CDs and to develop a mechanism for international cooperation. The discussion focused on three broad topics: contents of CDs; collection, assessment, and evaluation of data; and procedures for the preparation and exchange of CDs on specific chemicals. Annex A on the various procedures for standard setting by EC Member States, countries outside the EC, and international organizations and Annex B on the proposed contents of the CDs are also included.

Biological exposure and/or effect limits, facts, fallacies and uncertainties: general principles.

When looking for facts, fallacies and uncertainties of the use of biological exposure limits one has at first to discuss the general principles of biological monitoring (BM) and biological effect monitoring (BEM) because they determine the validity of the data that underpin the biological exposure limits. A difference between countries in preferred BM-methods can be observed. The terminology is still confusing: in addition to BM and BEM, biomonitoring and biological markers also are used. There are a number of problems in respect of the inter- and intra-individual variability in internal exposure and effect at similar exposure levels due to differences in for example, physical workload, body composition and genetics. Toxicokinetic models based on data from individual workers should be developed in order to get information on the variability and the cause of this. Both kinetics and dynamics may be sex-dependent. To date, BM methods have been tentatively suggested for only about 10 per cent of the regulated industrial chemicals. BM and BEM programmes yield important extra information on exposure and health risk, not to be gained by environmental monitoring alone.

Biological exposure and/or effect limits, facts, fallacies, and uncertainties: practical aspects.

In the preceding article general principles in setting biological occupational exposure limits (BOEL) and effect limits (BOEEL) were discussed. Here monitoring in every day occupational health practice is discussed. The specific objectives of biological monitoring (BM) and biological effect monitoring (BEM) determine to a large extent the choice of the parameters to be measured. According to the objective, the assessment may be either simple or sophisticated. The choice of an appropriate reference is essential for a valid evaluation of internal exposure, health risk and state of health. The measurement strategy depends on the working mechanism and the kinetics of the chemical. Protocols for BM and BEM-programmes should be regularly updated. Different compounds of the same metal may carry widely different health risks. In general it is necessary to correct the excretion of chemicals for dilution of the urine.

Work hygienic behaviour as modifier of the lead air-lead blood relation.

Knowledge of hygienic behaviour at the workplace appears to explain the low correlation between external and internal exposure. Differences in hygienic behaviour explain at least the same magnitude of variation in levels of lead in blood as the level of lead in air. Adding hygienic behaviour to the lead air-lead blood model increases the accuracy of prediction of PbB. In this study, the frequency of putting on/off gloves and the frequency of hand-mouth nose/shunt are the strongest modifiers of the PbA-PbB relation. In general, the actual behaviour of workers exposed to chemical agents may explain the often observed poor or moderate relationships between environmental and biological monitoring parameters of chemical exposure in occupational health studies.

Standard setting in occupational health: "philosophical" issues.

This paper discusses various "philosophical" issues in standard setting in occupational and environmental health, i.e., general principles, actual procedures for standard setting, inter- and intra-agency discrepancies in procedures and criteria, and choices and decisions in the preparation of criteria documents and in the evaluation of the toxicology databases. Unpublished, possibly confidential information should be made available to expert committees, workers, and the general public. There is an urgent need to improve the validity of the toxicology databases that have to underpin occupational and environmental exposure limits. Standard setting requires various ethically loaded choices and decisions by experts, employees, managers, government officials, and politicians.

Urinary mercury levels and early changes in kidney function in dentists and dental assistants.

Mercury exposure and renal function parameters were examined in 68 dentists and 64 dental assistants. The levels of mercury in urine were low: only three individuals exceeded 20 micrograms/l. Increased excretion of urinary proteins and increased activity of urinary enzymes were observed. This enhanced prevalence of renal function changes appeared not to be related to the mercury urine level, age, sex, or smoking and drinking habits. Only for men was a positive relation between the level of mercury in urine and the activity of beta-galactosidase found. The proteinuria may be due to one or more potential nephrotoxic agents used in dental practice.

Short-term occupational exposure limits: a simplified approach.

This paper presents a simplified proposal for setting health standards based on short-term exposure limits (STEL). It presents an alternative to the approach by the German MAC Commission: with only three instead of five categories, no fixed excursion factors, but ranges; more restrictive duration of sampling; no fixed frequencies of the number of accepted excursions per workshift.

Renal function of chrome-plating workers and welders.

The influence of occupational exposure to water-soluble chromium (VI) on renal function was examined. In male chrome-plating workers (n = 29), stainless steel welders (n = 45), boilermakers (n = 18) and a control group of workers (n = 71), the level of chromium in the urine (Cr-U), the chromium clearance, and sensitive renal function parameters were determined. The glomerular-function parameters of the chrome-plating workers (Cr-U 1 to 34 micrograms/g creat) and welders (Cr-U 1 to 62 micrograms/g creatine) appeared to differ from those of the boilermakers (Cr-U 0.3 to 1.5 micrograms/g creatine) and controls (Cr-U 0.1 to 2 micrograms/g creatine). The renal function parameters were not related to chromium concentration in the urine or to chromium clearance.

Non-auditory effects of noise in industry. VII. Evaluation, conclusions and recommendations.

The results of epidemiological studies on non-auditory effects of noise in industry are commented upon. The present state of the art does not permit any definite conclusion to be drawn about the risk of hypertension. Annoyance by noise is widespread; it has many different aspects and it has been studied in detail in this project. Combinations of working conditions should be studied that produce interaction effects overloading psychological or physiological systems. Some examples are given. Standards and guidelines for industrial exposure to noise should also prevent wellknown, non-auditory effects, such as communication problems, which result in social isolation.

Levels of metals in hair of young children as an indicator of environmental pollution.

In 1982 the levels of lead (Pb), cadmium (Cd), vanadium (V), copper (Cu), and selenium (Se) were determined in hair of 231 four- to five-year-old children. The objective was to explore the feasibility of using metal-in-hair levels in groups of children as an indicator of environmental pollution. The study was carried out in four areas, which were assumed to differ in ambient pollution by metals. A questionnaire on personal data, socioeconomic status, intake of beverages, and life-style was completed by the parents. The metal-in-hair levels covered a large range. The variables pertaining to location together with sex, presence of a garden, and drinking of coffee and/or tea explained 32% of the variance of Pb, 24% of the variance of Cd, and 21% of the variance of V. The total variance explained by all measured questionnaire items was at best 38%. The location was the most important factor. Cu and Se levels did not differ between the locations.

Definitions of monitoring activities and their relevance for the practice of occupational health.

The authors discuss the definitions of environmental monitoring (EM), biological monitoring (BM) and health surveillance (HS) as agreed upon by a CEC/NIOSH/OSHA-seminar in 1980. They emphasize the essential differences in underlying principles. They add a fourth definition of biological effect monitoring (BEM). Each method has its own assets and liabilities. Moreover, EM and BM require another decision-making process (situation-centered) then BEM and HS (client-entered) of measures to be taken. When the differences between the four approaches are not taken into account, valid preventive measures may be hampered.

Trace metals and coronary heart disease risk indicators in 152 elderly men (the Zutphen Study).

Information about trace metals and coronary heart disease risk indicators was collected in 1977 among 152 men aged 57-76 years in the town of Zutphen, the Netherlands. Serum zinc, serum copper, blood cadmium, and blood lead were determined by atomic absorption spectrometry and serum lithium by flame emission spectrometry. After uni- and multivariate regression analysis, the following statistically significant relations were found: serum zinc was inversely related to resting heart rate; serum copper was positively related to cigarette smoking and inversely to high density lipoprotein cholesterol; blood cadmium was strongly positively related to cigarette smoking and inversely to Quetelet index; the positive relation between blood lead and cigarette smoking was of borderline significance; and blood lead was related to blood pressure, with the relation being stronger for systolic than for diastolic blood pressure.