NORA Manufacturing Sector Strategic Goals
9278427 - Phthalate Exposure Screening and Cohort Identification
Principal Investigator (PI)
Primary Goal Addressed
Secondary Goal Addressed
Attributed to Manufacturing
Phthalates are used as plasticizers and solvents in consumer and industrial products. Certain phthalates are reproductive toxicants in animals. Phthalate occupational exposure data is limited. This project aims to assess phthalate exposures among workers in various industries in order to identify groups with likely occupational exposure. Three phthalates, di(2-ethylhexyl)phthalate, dibutyl phthalate, and diethyl phthalate were selected for exposure monitoring based on toxicity and other information. Over three years, the exposure of 156 workers was monitored by measuring metabolites in urine samples collected on days the target phthalates were used. Demographic and work process information were also collected. Phthalate exposures in each industry sector were compared to general population levels. Exposure information obtained in this project will be useful for risk assessment and for planning epidemiological studies.
The purpose of this project is to identify worker groups with phthalate exposures that significantly exceed NHANES background levels by using biological monitoring for phthalate metabolites to screen workers in a variety of workplaces, and to identify, where feasible, potential predictors of occupational phthalate exposure. The research objectives of this project are a) to conduct preliminary exposure monitoring of workers in industries where diethyl phthalate, dibutyl phthalate, and di(2-ethylhexyl) phthalate are produced or used by collecting urine samples for phthalate metabolite determination from workers on phthalate-related processes, b) to compare urinary metabolite levels for each industry group to NHANES general population levels to assess whether an occupational contribution is likely, and c) to identify possible predictors of phthalate occupational exposure. We will also evaluate the change (i.e. an increase) in metabolite levels within a shift as an indicator of occupational exposure. Exposure will be assessed on days when workers are handling the target phthalates.
In FY02, a study protocol was prepared and IRB approval was obtained. Data collection materials and sampling procedures were developed in FY03. The project required an extensive effort to identify and contact potential candidate companies for the study. A total of 156 workers were sampled in eight industry/professional sectors over a three year period (FY03-FY05). Two urine samples were collected per participant during a single work shift. Demographic and work process information needed to interpret the metabolite data was also obtained. Urine samples were analyzed for phthalate metabolites by the National Center for Environmental Health from FY03 into FY06. Creatinine and specific gravity were also determined for the urine samples. A database of demographic, work process, and urinary metabolite results was compiled in FY06. Data analysis and manuscript preparation began in FY07, with the first manuscript submitted to a journal in FY08. Additional manuscripts are planned in FY09.
The use of study findings by the such groups as the National Toxicology Program, Center for the Evaluation of Risks to Human Reproduction, the Environmental Protection Agency, the Phthalate Esters Panel of the American Chemistry Council, and various research groups for risk assessment, product stewardship, exposure assessment, and study planning can be evaluated by citations of papers published from this project in publications and documents produced by these groups.
Activity/Output 2.1.2 (09PPEXAAOG2.1.2): Completion of a software package that can manage exposure data collected from a variety of studies.
Phthalates are used as plasticizers and solvents in a variety of industrial, medical, and consumer products. Certain phthalates are reproductive and developmental toxicants in animals, and are also suspected endocrine disruptors. After reviewing the reproductive toxicity of 43 chemicals in animals, NIOSH identified phthalates as a priority chemical for reproductive study in humans. Similarly, reviews of seven phthalates by the National Toxicology Program (NTP) also indicated the need to study phthalates as priority suspected human reproductive toxicants. Interest in phthalate exposure and possible health effects in humans has been high in the scientific and popular media.
While information on general population exposure to phthalates is known through NHANES surveys, little is known about potentially higher phthalate exposure among workers in industries where phthalates are produced or used, nor how worker and general population exposures compare. Until recently, phthalate exposures have been difficult to determine accurately since phthalates are environmentally ubiquitous and environmental samples can be contaminated by the parent compound either at the point of collection or in the laboratory. The National Center for Environmental Health (NCEH), however, has developed highly sensitive and specific methods to measure phthalate metabolites in urine, thereby minimizing problems arising from environmental contamination.
The objectives of this project are: 1) to use biological monitoring to screen workers in a variety of workplaces in order to identify worker groups with phthalate exposures that significantly exceed NHANES background levels; and 2) to identify, where feasible, potential predictors of occupational phthalate exposure levels.
Intermediate goals are to: a) to conduct preliminary exposure monitoring of workers in industries where diethyl phthalate, dibutyl phthalate, and di(2-ethylhexyl) phthalate are produced or used, by collecting urine samples for phthalate metabolite determination from workers on phthalate-related processes, b) to compare urinary metabolite levels for each industry group to NHANES general population levels to assess whether an occupational contribution is likely, and c) to identify possible predictors of phthalate occupational exposure.