Larry K. Lowry

1-Pyrenol: A biomarker for occupational exposure to polycyclic aromatic hydrocarbons

Abstract A biological monitoring method using the major urinary metabolite of pyrene, 1-pyrenol, has been successfully used to assess the exposure of aluminum reduction plant workers to coal tar pitch-derived polycyclic aromatic hydrocarbons (PAHs). The method used high-performance liquid chromatography with a fluorescence detector. The net mean change between workers pre- and postshift urinary 1-pyrenol concentrations was seventeenfold greater than the net mean change found in controls. The data strongly indicated that the net change in urinary 1-pyrenol concentration in workers was greater than found in controls. Evidence for an effect due to smoking in this context was negligible. The data show a strong positive correlation between environmental pyrene and all 17 environmental PAHs that were analyzed and urinary 1-pyrenol, verifying that pyrene was an appropriate choice to use as a marker for coal tar pitch-derived PAHs.

Biological exposure index as a complement to the TLV

The American Conference of Governmental Industrial Hygienists (ACGIH) has recognized the value of biological monitoring for assessing worker exposure to chemicals. The ACGIH has established a Biological Exposure Indices Committee to review literature, prepare documentation analogous to the widely used TLVs, and recommend biological exposure indices (BEIs) for selected workplace chemicals. The BEIs represent an in-depth review of the literature and address such important issues as routes of exposure, absorption, metabolism, uptake, pharmacokinetics, sampling, methods of analysis, interferences (both chemical and metabolic), and interpretation of results. The recommended BEIs represent levels of some biological parameter that would be found in a worker following an 8-hour exposure (at moderate work) to the current TLV. To date, ten documentations and an introduction have been published by the ACGIH. They include toluene, xylene, ethylbenzene, carbon monoxide, styrene, benzene, n-hexane, lead, phenol, and trichloroethylene. Others are in preparation.

Determination of urinary 2-ethoxyacetic acid as an indicator of occupational exposure to 2-ethoxyethanol

Abstract A biological monitoring method which can detect human exposure to glycol ethers is described. A procedure for measurement of 2-ethoxyacetic acid (EAA), a urinary metabolite of 2-ethoxyethanol (EE), has been validated. EAA is removed from the urine specimen by a methylene chloride extraction of an EAA-tetrabutyl ammonium hydrogen sulfate ion pair. The ion pair subsequently reacts with pentafluorobenzyl bromide to produce the pentafluorobenzyl derivative of EAA. The EAA derivative is separated from other co-extracted urinary constituents by packed column gas chromatography and quantitated with flame ionization detection. 2-Butoxyacetic acid and 2-methoxyacetic acid can also be separated by this procedure. The analytical range for EAA is 5 to 100 μg/ml of urine; the limit of detection is 4 μg/ml, while the limit of quantitation is 7 μg/ml. The day-to-day relative standard deviation (Sr) was better than 4.7 percent; the corresponding within-day Sr was less than 2.0 percent. The procedure has been app...

The biological exposure index: Its use in assessing chemical exposures in the workplace

Human exposure to chemicals in the workplace has traditionally been assessed by determining the concentration of an airborne chemical in the workroom air. More recently, biological monitoring has been used to assess worker uptake of chemicals by all routes of exposure. Both approaches for the assessment of exposure and uptake are complementary. This relationship is examined, along with the advantages and limitations of using biological monitoring. The concept of the biological exposure index (BEI), developed by the American Conference of Governmental Industrial Hygienists (ACGIH), and information on the intended use and interpretation of BEIs are described. Examples are presented on the use of biological monitoring in NIOSH Health Hazard Evaluations (e.g., carboxyhemoglobin in blood to assess exposure to carbon monoxide, urinary metabolites of trichloroethylene to assess exposure to trichloroethanol, and 2-ethoxyacetic acid in urine to assess exposure to 2-ethoxyethanol). The progress of current research studies on the biological monitoring of volunteers exposed to paint spray solvents is presented, along with speculation on the future directions of biological monitoring research.

Occupational exposure to synthetic estrogens — the need to establish safety standards

An environmental survey of a plant formulating oral contraceptives demonstrated considerable variation in possible synthetic estrogen exposure to the plant personnel. Clinical epidemioiogical studies showed evidence of increased absorption of estrogens in some employees at the plant. In view of the companys considerable efforts to suppress dust from work areas, new approaches to containment may be necessary with biologically active dusts — including the establishment of a dust standard.An environmental survey of a plant formulating oral contraceptives demonstrated considerable variation in possible synthetic estrogen exposure to the plant personnel. Clinical epidemiological studies showed evidence of increased absorption of estrogens in some employees at the plant. In view of the companys considerable efforts to suppress dust from work areas, new approaches to containment may be necessary with biologically active dusts--including the establishment of a dust standard.

Urinary 4,4′-Methylenebis (2-Chloroaniline) (MBOCA): A Case for Biological Monitoring

Abstract 4,4-Methylenebis (2-chloroaniline), also known as MBOCA (or MOCA®), is an aromatic amine that is absorbed primarily through the skin. MBOCA is used as a curing agent in the castable polyurethane industry. It has also been identified as a suspect human carcinogen. Because of concerns that airborne monitoring would not truly assess the degree of worker absorption of MBOCA, the Polyurethane Manufacturers Association, an association of MBOCA users, implemented a voluntary biological monitoring program 15 years ago to assess and reduce worker exposure to MBOCA. Review of biological monitoring data, generated during the past 6 years using high performance liquid chromatography methods, has shown trends in reduced urinary MBOCA concentrations and thus reduced worker exposure. In addition, the results of the biological monitoring program, indicating worker exposure, have prompted the industry to initiate programs to reduce MBOCA exposure by engineering controls. The design of closed transfer systems in 1...