Summer

Gamma-glutamylcysteine synthetase (GCS) is the rate limiting enzyme in the synthesis of reduced glutathione (GSH), a major anti-oxidant in cells. Prolonged exposure to mercury as methyl mercury hydroxide (MMH) leads to increased GCS mRNA with accompanying incease in FSH levels. This increase in GSH may represent an adaptive response to mercury.

The objective of this cross-sectional study was to characterize the degree to which employees in Washington state are exposed to hard metal particulates (cobalt, chromium), and to identify engineering or environmental determinants of exposure. Ninety-nine subjects were recruited from 11 different shops.

As a result of its history of use and toxicity, arsenic and its health effects have been extensively studied. Arsenic is an element present naturally in the environment, is used in idustry and agriculture, and is extremely stable. Exposures to arsenical compounds may be common and represent a health concern.

Exposure to soil-borne contaminants can occur through ingestion, dermal absorption and/or inhalation pathways. The uncertainty associated with estimates of exposures vie these pathways is large, particularly for the dermal route. Site cleanup costs may be very sensitive to cleanup targets.

Radiation in the environment originates from cosmic, terrestrial and anthropogenic sources, including nuclear power plants and nuclear detonations. Radiation from muclear facility emissions is a major public concern, and extensive monitoring is carried out in the environs of nuclear facilities.

Dermal contact with contaminated soils is a potential pathway for chemical exposure.

Statistics compiled by the National Safety Council (NSC) and the US Bureaur of Labor Statistics indicate that the construction industry is one of the most hazardous to work in. The annual accident data state that of the approximately 5.9 million workers in the construction industry there were 1,300 deaths and 300,000 disabling injuries in 1992.

Since 1983, the Occupational Safety and Health Act (OSHA) has required employers to communicate to workers about the hazards of chemicals in their work areas, and about the means of reducing such hazards through use of personal protective equipment (PPE), safe work practices and engineering controls.

Breath analysis provides a non-invasive method for exposure assessment of volatile organic chemicals (VOC's). Low concentrations of VOC's in exhaled breath require concentration prior to analysis, typically by use of a sorbent or cryogen. Tenax, the most common sorbent, requires thermal desorption for analysis.

Assessing exposures to chemicals that can be absorbed through the skin presents the industrial hygienist with a perplexing and sometimes frustrating dilemma. The fact that three of the articles appearing in the February 1993 AIHA Journal addressed surface wipe sampling is a testament to an increasing concern over the impact of dermally absorbed chemicals.

Military aviators are an expensive national resource. This is a function of the multimillion dollar cost of aviator training. To optimize the investment in these individuals, only those candidates who are both currently healthy and deemed likely to be free of future chronic disease are accepted into training.

Ventilation systems in industry often undergo modifications due to process changes or to perceived need for different airflow for workers or workstations. It is difficult to determine the required modifications if one cannot predict the effects of making such changes to a system.

Workers in the US and around the world face significant risks for dermal exposure to chemicals. In the US in 2003 43,400 skin disease cases were reported to the Bureau of Labor and Statistics for a total incidence rate of 4.9 per 10,000 workers (OSHA 2005) Dermatitis is the second most commonly reported occupational disease in Washington State.

Pen and paper assessment methods or checklists are used to evaluate jobs, assess exposure, and identify risks that have the potential to cause injuries to the neuro-musculoskeletal systems in the body.

Emissions into the environment, or workplace, of toxic air contaminants that have adverse human health effects are of concern for safety and regulatory reasons. The American Conference of Governmental Industrial Hygienists (ACGIH) annually publishes a Threshold Limit Value (TLV) booklet that lists a TLV for approximately 600 hazardous chemicals.

Pesticides are widely used in the United States both in residential and agricultural settings. When used properly, pesticides can be effective in the control of a variety of pests including insects, weeds, rodents, and fungi. Commercial and consumer application of pesticides has become a common practice for control of pests in non-agricultural environments.

It has been shown that people with asthma are a sensitive subpopulation to inhaled sulfur dioxide (SO2); decrements in pulmonary function occur in subjects after exposure to low concentrations even for a short duration of time. There is a great amount of inter-individual variation in response to SO2.

Recent research has indicated that changes in daily mortality have been correlated with daily PM10 and PM2.5 levels below the current 24 hour National Ambient Air Quality Standards (NAAQSs) for PM10 in the United States. As a result, new NAAQSs for PM2.5 were recommended.

Asthma is a clinical syndrome characterized by airway hyperactivity leading to episodes of reversible airway constriction. Symptoms manifest clinically as shortness of breath, cough, chest tightness, and wheezing and can be treated with a variety of medications.

Arsenic distributes throughout the body, able to pass the placental barrier and reach the developing fetal brain. High-dose inorganic arsenic exposure to animals during development has been associated with neural tube defects, exencephaly and other disorders, although the molecular mechanisms underlying potential effects from low-dose exposure are uncertain.

Environmental exposure to methylmercury (MeHg) has been recognized as a public health concern. MeHg has been shown to exert selective damage to the central nervous system after both adult and fetal exposures. The fetal brain seems to exhibit a higher sensitivity to MeHg. However, the mechanism of toxicity is still poorly understood.

When performing human health risk assessments, dermal-soil risks frequently need to be calculated. Current regulatory guidance utilizes multiple, non-event specific point estimates of input parameters to produce a single, deterministic estimate of exposure. The Soil Contact Rate (SCR) is proposed as a metric of dermal exposure to soil.

Characteristics specific to children make them a sensitive subpopulation in teRMS of environmental exposure to pesticides. Compared to the general adult population, children have higher rates of metabolism, less mature immune systems, and have different diets (NRC, 1993.) Children also are believed to ingest more soil and house dust than do adults.

Nuclear factor (NF)-kB is a transcriptional factor known to mediate the inducible expression of a wide variety of genes that are involved in inflammatory and other cytotoxic reactions in various cell types.

The goal of this project is to validate a passive sampler that is stable for seven-day monitoring of personal exposures to aldehydes for large population studies. The target aldehydes are formaldehyde, acetaldehyde, acrolein, crotonaldehyde, glyoxal, and methylglyoxal and were selected according to their toxicity and prevalence.

Methyl mercury, a potent neurotoxicant, accumulates in the brain as well as kidney during chronic exposure. We evaluated the efficacy of DMPS, a tissue-permeable metal chelator, to reduce brain and kidney Hg levels and to promote Hg elimination in urine following exposure of F-344 rats to methyl mercury hydroxide MMH, (10 ppm) in drinking water for up to 9 weeks.

Physiologic sampling pumps (PSPs) seek to change pump rate in proportion to the minute ventilation of the worker. The aim to account for (1) differences in minute ventilation between individuals and (2) correlation between air concentration of contaminants and minute ventilation. This dissertation presents PSP theory and evaluated a new PSP for use in the real world.

Phospholipid hydroperoxide glutathione peroxidase (GPx4) is a member of the gamily of selenium dependent enzymes that catalyze the reduction of cell membrane-bound phospholipid hydroperoxides in situ and thus, protects against membrane damage.

This thesis contains analyses of new statistical, computational, and optical tools that can be used to estimate the time course of dermal absorption after a pesticide residue is deposited on the skin. Chapter 1 contains a statistical model that was designed to determine how dermal residence time on the skin influences the absorbed dose.