This article provides an overview of the environmental patterns and dynamics of copper from the perspective of issues that affect our ability to examine current human exposures. It presents selected summary information on the levels of copper found in various media and exposure pathways from a variety of information sources, and discusses the breadth and the limitations of this information. The analysis presented focuses on the ability to provide quantitative values for both external metrics of exposures (microenvironmental levels) and internal biological markers of exposure. The status of the current information on environmental copper is placed within a conceptual framework that can be used to identify data gaps, assess the utility of current biological markers of exposure, and examine the need for systematic and consistent data-gathering studies to improve our ability to complete exposure assessments. A primary concern is the exposure to copper through potable water supplies; this is considered within a framework that examines copper levels and distribution in food, soil, air and sediments, as well as the levels found in biological media such as urine, blood, and hair. An existing water consumption model for copper and associated exposure factors is briefly discussed. This type of model will eventually be valuable within a total exposure analysis modeling framework that can consider and prioritize exposures from multiple routes and differentiate levels of concern for both excesses and deficiencies in exposure, an important issue, since copper is an essential nutrient. Finally, this review attempts to examine the needs for better information using as a basis the concerns briefly mentioned in the recent NRC report "Copper in Drinking Water" (National Research Council, 2000).

The 1990 Clean Air Act mandated oxygenation of gasoline in regions where carbon monoxide standards were not met. To achieve this standard, methyl tertiary butyl ether (MTBE) was increased to 15% by volume during winter months in many locations. Subsequent to the increase of MTBE in gasoline, commuters reported increases in symptoms such as headache, nausea, and eye, nose, and throat irritation. The present study compared 12 individuals selected based on self-report of symptoms (self-reported sensitives; SRSs) associated with MTBE to 19 controls without self-reported sensitivities. In a double-blind, repeated measures, controlled exposure, subjects were exposed for 15 min to clean air, gasoline, gasoline with 11% MTBE, and gasoline with 15% MTBE. Symptoms, odor ratings, neurobehavioral performance on a task of driving simulation, and psychophysiologic responses (heart and respiration rate, end-tidal CO(2), finger pulse volume, electromyograph, finger temperature) were measured before, during, and immediately after exposure. Relative to controls, SRSs reported significantly more total symptoms when exposed to gasoline with 15% MTBE than when exposed to gasoline with 11% MTBE or to clean air. However, these differences in symptoms were not accompanied by significant differences in neurobehavioral performance or psychophysiologic responses. No significant differences in symptoms or neurobehavioral or psychophysiologic responses were observed when exposure to gasoline with 11% MTBE was compared to clean air or to gasoline. Thus, the present study, although showing increased total symptoms among SRSs when exposed to gasoline with 15% MTBE, did not support a dose-response relationship for MTBE exposure nor the symptom specificity associated with MTBE in epidemiologic studies.ImagesFigure 1Figure 2

BackgroundIndividuals involved in rescue, recovery, demolition, and cleanup at the World Trade Center (WTC) site were exposed to a complex mixture of airborne smoke, dust, combustion gases, acid mists, and metal fumes. Such exposures have the potential to impair nasal chemosensory (olfactory and trigeminal) function.ObjectiveThe goal of this study was to evaluate the prevalence of chemosensory dysfunction and nasal inflammation among these individuals.MethodsWe studied 102 individuals who worked or volunteered at the WTC site in the days and weeks during and after 11 September 2001 (9/11) and a comparison group with no WTC exposure matched to each participant on age, sex, and job title. Participants were comprehensively evaluated for chemosensory function and nasal inflammation in a single session. Individual exposure history was obtained from self-reported questionnaires.ResultsThe prevalence of olfactory and trigeminal nerve sensitivity loss was significantly greater in the WTC-exposed group relative to the comparison group [prevalence ratios (95% confidence intervals) = 1.96 (1.2–3.3) and 3.28 (2.7–3.9) for odor and irritation thresholds, respectively]. Among the WTC responders, however, individuals caught in the dust cloud from the collapse on 9/11 exhibited the most profound trigeminal loss. Analysis of the nasal lavage samples supported the clinical findings of chronic nasal inflammation among the WTC-exposed cohort.ConclusionsThe prevalence of significant chemosensory impairment in the WTC-exposed group more than 2 years after their exposure raises concerns for these individuals when the ability to detect airborne odors or irritants is a critical safety factor.Relevance to clinical practiceThis outcome highlights the need for chemosensory evaluations among individuals with exposure to acute high or chronic levels of airborne pollutants.

The 1990 Clean Air Act mandated oxygenation of gasoline in regions where carbon monoxide standards were not met. To achieve this standard, methyl tertiary butyl ether (MTBE) was increased to 15% by volume during winter months in many locations. Subsequent to the increase of MTBE in gasoline, commuters reported increases in symptoms such as headache, nausea, and eye, nose, and throat irritation. The present study compared 12 individuals selected based on selfreport of symptoms (self-reported sensitives; SRSs) associated with MTBE to 19 controls without self-reported sensitivities. In a double-blind, repeated measures, controlled exposure, subjects were exposed for 15 min to dean air, gasoline, gasoline with 11% MTBE, and gasoline with 15% MTBE. Symptoms, odor ratings, neurobehavioral performance on a task of driving simulation, and psychophysiologic responses (heart and respiration rate, end-tidal CO2, finger pulse volume, electromyograph, finger temperature) were measured before, during, and immediately after exposure. Relative to controls, SRSs reported significantly more total symptoms when exposed to gasoline with 15% MTBE than when exposed to gasoline with 11% MTBE or to dean air.However, these differences in symptoms were not accompanied by significant differences in neurobehavioral performance or psychophysiologic responses. No Using a double-blind cross-over design, Prah et al. (8) exposed healthy subjects to 1.4 ppm MTBE versus clean air for 1 hr.Cain et al. (9) exposed healthy subjects for 1 hr to each of three conditions: 1.7 ppm MTBE, 7.1 ppm mixture of 17 volatile organic compounds, and clean air. Neither study found an increase in symptoms, a reduction in neurobehavioral performance, or changes on measures of eye irritation (tear film breakup). The number of polymorphonuclear neutrophil leukocytes in nasal lavage fluid samples was increased only 18-24 hr after exposure to volatile organic compounds (9). In these studies, blood levels of MTBE were higher than the upper quartile levels assessed in the cross-sectional studies of workers. More recently, Nihlen et al. (7) exposed 10 healthy males to 5, 25, and 50 ppm MTBE and found that subjects reported significantly higher ratings of solvent smell with higher exposure to MTBE. Ratings of odor declined over time, suggesting habituation to the odor. No increase in symptoms or changes in objective measures of eye irritation was observed (e.g., tear film breakup time, redness). Nasal airway resistance increased significantly after exposure, but the effect was not correlated with exposure. Thus, in healthy subjects, MTBE exposures under controlled conditions did not replicate the symptoms reported either anecdotally or in cross-sectional community studies. These controlled exposures to MTBE, however, were not those of typical exposures such as refueling or driving, where MTBE is encountered only as an additive to gasoline. Moreover, controlled exposure studies to date have not included self-reported sensitive individuals.As is observed with other noxio...

Despite claims that exposure to fragranced products may trigger ocular and respiratory symptoms among asthmatics, we found no evidence that 30 min of exposure to one of two fragranced aerosols elicited objective adverse effects in the ocular or nasal mucosa of mild and moderate asthmatics. While physiological mechanisms of fragrance impact may yet be responsible for some of the adverse reports among asthmatics following fragrance exposure, such reports may also reflect a non-physiological locus of symptom perception triggered by other sensory cues.