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PubMed2003

Association of low-level ozone and fine particles with respiratory symptoms in children with asthma.

CONTEXT: Exposure to ozone and particulate matter of 2.5 microm or less (PM2.5) in air at levels above current US Environmental Protection Agency (EPA) standards is a risk factor for respiratory symptoms in children with asthma. OBJECTIVE: To examine simultaneous effects of ozone and PM2.5 at levels below EPA standards on daily respiratory symptoms and rescue medication use among children with asthma. DESIGN, SETTING, AND PARTICIPANTS: Daily respiratory symptoms and medication use were examined prospectively for 271 children younger than 12 years with physician-diagnosed, active asthma residing in southern New England. Exposure to ambient concentrations of ozone and PM2.5 from April 1 through September 30, 2001, was assessed using ozone (peak 1-hour and 8-hour) and 24-hour PM2.5. Logistic regression analyses using generalized estimating equations were performed separately for maintenance medication users (n = 130) and nonusers (n = 141). Associations between pollutants (adjusted for temperature, controlling for same- and previous-day levels) and respiratory symptoms and use of rescue medication were evaluated. MAIN OUTCOME MEASURES: Respiratory symptoms and rescue medication use recorded on calendars by subjects' mothers. RESULTS: Mean (SD) levels were 59 (19) ppb (1-hour average) and 51 (16) ppb (8-hour average) for ozone and 13 (8) microg/m3 for PM2.5. In copollutant models, ozone level but not PM2.5 was significantly associated with respiratory symptoms and rescue medication use among children using maintenance medication; a 50-ppb increase in 1-hour ozone was associated with increased likelihood of wheeze (by 35%) and chest tightness (by 47%). The highest levels of ozone (1-hour or 8-hour averages) were associated with increased shortness of breath and rescue medication use. No significant, exposure-dependent associations were observed for any outcome by any pollutant among children who did not use maintenance medication. CONCLUSION: Asthmatic children using maintenance medication are particularly vulnerable to ozone, controlling for exposure to fine particles, at levels below EPA standards.

Air Pollutants↗
PubMed2004

Heavy metal content of ayurvedic herbal medicine products.

CONTEXT: Lead, mercury, and arsenic intoxication have been associated with the use of Ayurvedic herbal medicine product (HMPs). OBJECTIVES: To determine the prevalence and concentration of heavy metals in Ayurvedic HMPs manufactured in South Asia and sold in Boston-area stores and to compare estimated daily metal ingestion with regulatory standards. DESIGN AND SETTING: Systematic search strategy to identify all stores 20 miles or less from Boston City Hall that sold Ayurvedic HMPs from South Asia by searching online Yellow Pages using the categories markets, supermarkets, and convenience stores, and business names containing the word India, Indian cities, and Indian words. An online national directory of Indian grocery stores, a South Asian community business directory, and a newspaper were also searched. We visited each store and purchased all unique Ayurvedic HMPs between April 25 and October 24, 2003. MAIN OUTCOME MEASURES: Concentrations (microg/g) of lead, mercury, and arsenic in each HMP as measured by x-ray fluorescence spectroscopy. Estimates of daily metal ingestion for adults and children estimated using manufacturers' dosage recommendations with comparisons to US Pharmacopeia and US Environmental Protection Agency regulatory standards. RESULTS: A total of 14 (20%) of 70 HMPs (95% confidence interval, 11%-31%) contained heavy metals: lead (n = 13; median concentration, 40 microg/g; range, 5-37,000), mercury (n = 6; median concentration, 20,225 microg/g; range, 28-104,000), and/or arsenic (n = 6; median concentration, 430 microg/g; range, 37-8130). If taken as recommended by the manufacturers, each of these 14 could result in heavy metal intakes above published regulatory standards. CONCLUSIONS: One of 5 Ayurvedic HMPs produced in South Asia and available in Boston South Asian grocery stores contains potentially harmful levels of lead, mercury, and/or arsenic. Users of Ayurvedic medicine may be at risk for heavy metal toxicity, and testing of Ayurvedic HMPs for toxic heavy metals should be mandatory.

Arsenic↗
PubMed1998

Chemicals in the workplace: incorporating human neurobehavioral testing into the regulatory process.

In February 1996, the United Kingdom Health and Safety Executive sponsored a workshop on the role of human neurobehavioral tests in the regulation of chemical exposures in the workplace. This paper presents the review of neurobehavioral testing that was initially prepared for the workshop but has been expanded and updated for publication. Information sources for the review were drawn from "preamble to the regulation," in the 1989 air contaminants project, an attempt by the Occupational Safety and Health Administration to update the 1968 regulatory limits of workplace exposures. The scientific citations listed in the preamble provide a chemical database to review for evidence of neurobehavioral testing to support limit setting. Several conclusions emerged: 1) A wide range of nervous system effects were reported in the scientific citations for the 172 chemicals identified with effects on the nervous system; 2) Citations of studies with human neurobehavioral test results are used to support limit setting, but many are old studies primarily of acute effects; 3) There is frequently a delay of several years after publication before studies with neurobehavioral testing are cited in regulatory forums; 4) With the 1989 proposed regulatory limits never legally adopted, there has not been an update for most of the substances affecting the nervous system since 1971; 5) Investigators should be more aware of the regulatory process and submit studies reporting neurobehavioral test results to organizations that regulate and recommend workplace exposure limits; 6) Issuances in the Federal Register by the U.S. Environmental Protection Agency provide a framework for assessing neurotoxic risks that can be used by investigators to help identify and report nervous system effects using neurobehavioral testing in a more uniform fashion.

Behavior↗
PubMedDate not supplied

Results of the L5178Y mouse lymphoma assay and the Balb/3t3 cell in vitro transformation assay for eight phthalate esters.

Eight phthalate esters, with alcohol chain lengths of 1-11 carbon atoms and with various degrees of branching, were tested in vitro in the L5178Y mouse lymphoma mammalian cell mutation assay and in the Balb/3T3 cell transformation assay. The tests were performed as part of a voluntary testing agreement between the Chemical Manufacturers Association's Phthalate Esters Panel and the United States Environmental Protection Agency (US EPA). The esters tested were: dimethyl phthalate (DMP), di-n-butyl phthalate (DBP), butyl benzyl phthalate (BBP), di-¿n-hexyl, n-octyl, n-decyl¿ phthalate (610P), di-isononyl phthalate (DINP), di-¿heptyl, nonyl, undecyl¿ phthalate (711P), di-isodecyl phthalate (DIDP) and di-undecyl phthalate (DUP). Both DMP and DBP were found to produce significant increases in the mutant frequency in the mouse lymphoma assay in the presence but not in the absence of an Aroclor-induced rat liver activation system (S-9). Ester 610P gave equivocal results in the mouse lymphoma assay in the presence and absence of rat liver S-9. There was no indication of mutagenic potential for any of the other test materials in the mouse lymphoma assay, and none of the test materials increased transformation frequency in the Balb/3T3 cell transformation assay. Aldehyde metabolites of the de-esterified alcohols are postulated to play a role in the positive results for DMP and DBP.

3T3 Cells↗
PubMedDate not supplied

Cyclodextrin-aided capillary electrophoretic separation and laser-induced fluorescence detection of polynuclear aromatic hydrocarbons (PAHs).

Two neutral cyclodextrins (CDs), hydroxypropyl-beta-CD (HP beta OD) and methyl-beta-CD (M beta CD), and two negatively charged forms, carboxymethyl-beta-CD (CM beta CD) and sulfobutylether-beta-CD (SB beta CD), were used to demonstrate the principle of separation of hydrophobic and non-charged polynuclear aromatic hydrocarbons (PAHs) by capillary electrophoresis (CE) based on differential partitioning of analytes between the CDs. The estimation of the partition coefficient (Ki) confirmed that the PAH components which partitioned most to the negative cyclodextrin (i.e. with the highest Ki) exhibited the longest migration time. The Ki values obtained for the CM beta CD-HP beta CD system are all below 1, indicating that the PAHs prefer to remain in the neutral HP beta CD. The Ki values for the SB beta CD-M beta CD buffer are all greater than 1, and cover a wider range, indicating preference of the PAHs for the anionic derivative. Methods were applied for separation of a PAH mixture containing various important PAHs on the US Environmental Protection Agency priority list. This novel procedure provided much better separation of PAH isomers, including benzo[a]pyrene and benzo[e]pyrene, than has been reported previously using CE. The system was applied to the sensitive determination of nanomolar levels of PAHs in contaminated soil.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed2000

In-line coupling capillary electrochromatography with amperometric detection for analysis of explosive compounds.

Amperometric detection at a bare gold electrode has been in-line coupled with capillary electrochromatography (CEC) for analysis of nitroaromatic and nitroamine explosives in contaminated soils and ground water. The CEC column packed with 3 microm C18 particles performed best using a mobile phase containing 70-80% methanol, 30 or 20% water, 5 mM sodium dodecyl sulfate (SDS) and 10mM 2-(N-morpholino)ethanesulfonic acid (MES). In contrast, the separation column packed with 1.5 km C18 particles exhibited the best separation when only 30% methanol was added to a mobile phase containing 70% water, 7 mM SDS, and 10 mM MES. The detection, based on electrochemical reduction of the explosives (-0.7 or -1 V vs. Ag/AgCl, depending upon the level of methanol in the mobile phase), was compatible with such mobile phases. The detection limits for 13 explosives ranged from 100 to 200 ppb, i.e., about twofold better than those obtained with electrokinetic chromatography (EKC)/amperometric detection. From an operational viewpoint, exhaustive column conditioning was a prerequisite and care should be taken to prevent bubble formation and current breakdown during the course of separation. The CEC column equipped with amperometric detection successfully measured explosives in ground water and extracts prepared from contaminated soils and the results obtained agreed well with those of the U.S. Environmental protection Agency (EPA) method.

Azocines↗
PubMed1999

Assessing the human health risk of atmospheric particles.

The health implications of atmospheric particulate matter have become a topic of much interest on both sides of the Atlantic, but especially in the USA, where they were at the centre of the debate over the Environmental Protection Agency's (EPA) revision of the National Ambient Air Quality Standard in 1997. Much of this debate revolves around claims that particulate matter (usually represented by PM10) in the atmosphere directly influences mortality, hospital admissions with respiratory diseases, and so on. In this paper, we take a critical look at one of these issues, the influence of PM10 on deaths in the elderly population. Two data sets are considered, one from Birmingham (Alabama) and the other from Chicago. In both cases we find a significant PM10-mortality relationship in some of the models fitted, but not in others. Other issues considered include the existence of a threshold below which PM10 has no discernible influence, the interaction with other pollutants and the mortality displacement or harvesting effect (the theory that the direct effect of PM10 is limited to a very small subset of the population who are already critically ill and whose death is only advanced by a few hours or days as a result of air pollution). Overall, our conclusion is that there are too many uncertain issues to allow us to make definitive statements about a causal relationship between PM10 and mortality.

Air Pollution↗
PubMed1995

Update of the mortality experience of employees with occupational exposure to 1,2-dibromo-3-chloropropane (DBCP).

DBCP (1,2-dibromo-3-chloropropane), a nematocide, was used in the United States from the mid-1950s until 1977. The U.S. Environmental Protection Agency (EPA) restricted and eventually banned its use after the 1977 discovery of DBCP-induced sterility in production workers. The present study is an update of the mortality (1957-1989) experience of a cohort of 548 male employees who had potential for exposure in the production and formulation of DBCP. While adjusting for age, calendar-year, and pay status of all other Midland-area Dow Chemical male employees, there were 68 total observed deaths in the cohort compared to 72.1 expected (Mantel Haenszel Relative Risk 0.9, 95% Confidence Interval 0.7-1.2) and 19 deaths from all malignancies compared to 19.0 expected (RR 1.0, 95% CI 0.6-1.6). Of the a priori anatomic cancer sites of interest, there were no deaths from stomach, liver, kidney, testes, or nasal cavity cancers. Altogether, there were 7 deaths from lung cancer compared to 6.6 expected (RR 1.1, 95% CI 0.5-2.3). Among the 81 employees with exposure categorized as direct for 1 or more years, there were 3 observed lung cancer deaths compared to 0.9 expected (RR 3.3, 95% CI 1.1-9.6). Smoking was a confounding factor in the interpretation of this observation. Although the present analysis nearly doubled the number of person-years from the original study, the conclusions remain limited by the cohort's size and duration of follow-up.

Antinematodal Agents↗
PubMed1998

Mixed-mode separation of polycyclic aromatic hydrocarbons (PAHs) in electrokinetic chromatography.

A mixed-mode separation technique has been developed and optimized for the separation of the 16 Environmental Protection Agency (EPA) priority polycyclic aromatic hydrocarbons (PAHs). The procedure utilized two different buffer additives as pseudo-stationary phases with different selectivities towards the analytes. Sodium dioctyl sulfosuccinate (DOSS) displayed selectivities for PAHs which were somewhat similar to the C18 phase in reversed-phase high performance liquid chromatography (HPLC). High acetonitrile content required for an effective separation prevented the formation of micelles as confirmed by fluorescence spectroscopy. Consequently, the separation could be attributed to the solvophobic association of the PAH molecules with hydrophobic chains of the DOSS surfactant. In another mode of separation, sulfobutylether-beta-cyclodextrin (SB-beta-CD) separated the 16 PAHs on the formation of inclusion complexes with the PAHs, and exhibited different selectivities for the PAHs compared to DOSS. SB-beta-CD and DOSS were then combined in the running buffer to form a mixed pseudo-stationary phase for the separation of the 16 PAHs. Due to the different selectivities of SB-beta-CD and DOSS for the PAHs, the separation of the 16 PAHs was appreciably improved compared to that using DOSS or SB-beta-CD alone. All the 16 PAHs were baseline-resolved using an optimized running buffer containing 22.5 mM DOSS, 15 mM SB-beta-CD, 15% acetonitrile and 5 mM hydroxypropyl-beta-cyclodextrin in 6 mM borate at pH 9.

Chromatography↗
PubMed1998

The combined effect of acetonitrile and urea on the separation of polycyclic aromatic hydrocarbons using sodium dioctyl sulfosuccinate in electrokinetic chromatography.

Sodium dioctyl sulfosuccinate (DOSS) or sodium di-2-ethylhexyl sulfosuccinate, a relatively nontoxic and negatively charged surfactant, was selected and optimized for the capillary electrophoretic separation of the 16 Environmental Protection Agency (EPA) priority polycyclic aromatic hydrocarbons (PAHs). This pseudostationary phase displayed selectivities for PAHs which were somewhat similar to the C18 phase in reversed-phase high performance liquid chromatography (HPLC). At high DOSS concentrations (> 30 mM), the hydrophobic interaction between DOSS and PAHs was pronounced and led to stronger retention of the latter. Consequently, acetonitrile was added to the running buffer to facilitate the elution of hydrophobic PAHs. In the absence of micelles, the separation mechanism was attributed to the solvophobic association of the PAH molecules with hydrophobic chains of the DOSS surfactant and there was a linear correlation between log k (retention factor) and the double bond number of the PAH. However, separations performed in an optimized buffer containing both DOSS and acetonitrile were not able to provide satisfactory performance. The separation of the 16 PAHs was then appreciably improved by adding urea to the running buffer to widen the separation window. At a high sample loading with UV detection, except for benzo[a]pyrene, benzo[b]fluoranthene and benzo[k]fluoranthene, all other PAHs were practically baseline-resolved using an optimized running buffer containing 50 mM DOSS, 35% acetonitrile and 5 M urea in 8-10 mM borate, pH 9. Laser-induced fluorescence permitted a very low sample loading and under such a running condition, a baseline resolution was obtained for these three most difficult PAHs. The addition of urea at this level, however, exhibited a noticeable quenching effect on the PAH fluorescent signal.

Acetonitriles↗
PubMed2005

Combination of cationic surfactant-assisted solid-phase extraction with field-amplified sample stacking for highly sensitive analysis of chlorinated acid herbicides by capillary zone electrophoresis.

This report describes a novel online field-amplified sample stacking (FASS) procedure to analyze 16 chlorinated acid herbicides. By using a poly(vinyl alcohol) (PVA)-coated capillary to reduce electroosmotic flow and introducing a methanol-water plug before sample loading, the sample injection time could be very long without loss of sample and separation efficiency. Under the optimized condition, the FASS procedure could provide great sensitivity enhancement (5000-10 000-fold) and satisfactory reproducibility (relative standard deviations of migration times less than 2.4%, relative standard deviations of peak areas less than 8.0%). Combined with cationic surfactant-assisted solid-phase extraction (CSA-SPE), the limit of detection of the herbicides ranged from 0.269 to 20.3 ppt, which are two orders lower than those of the US Environmental Protection Agency standard method 515.1. The CSA-SPE-FASS-CE method was successfully applied to the analysis of local pond water.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1985

Aneuploidy and health risk assessment: current status and future directions.

The U.S. Environmental Protection Agency (EPA) recently sponsored a workshop to discuss the contribution of aneuploidy to human disease and disability, the development of tests for detecting chemicals that induce aneuploidy and the relevance of these tests to human risk, and the current understanding of mechanisms by which aneuploidy arises. This summary is based on the presentations given at the workshop. It is hoped that this summary will stimulate thinking in this vitally important area of risk assessment and contribute to the establishment of priorities for basic research, development of new test methods, and validation of existing test approaches. Such research is needed to enhance the scientific basis of risk assessment for aneuploidy-producing chemicals.

Aneuploidy↗
PubMedDate not supplied

Carcinoma of the tonsil.

Although the experts acknowledge that there is no conclusive evidence linking secondhand smoke to head and neck cancer, a recent report by the Environmental Protection Agency classifies secondhand smoke as a group A carcinogen. There is strong evidence linking it to carcinoma of the lung. Whereas you may not be able to tell your patient that the same cause and effect is present for head and neck cancer, it is the editor's belief that this will one day be proven. Three experts agreed to treat this patient with surgery followed by full-course radiotherapy, although the surgical approaches differed. They included a marginal mandibulectomy, radical neck dissection, and plating of the remaining mandible (Dr. Strome) and a composite resection (Drs. Ward and Johnson). For reconstruction, options included a modified FAMM flap or a split-thickness skin graft (Dr. Strome), tongue flap or pectoralis major myocutaneous flap (Dr. Ward), or a split-thickness skin graft (Dr. Johnson). One consultant suggested resecting the neck mass and treating the primary tumor and neck with radiotherapy. A dental consultation is in order prior to radiotherapy (Dr. Goepfert). With regard to this woman's mental status, all the experts called for counseling. The husband should be included in the discussions (Dr. Strome and Ward) and consideration should be given to the Women's Right Advocacy Group (Dr. Johnson).

Aged↗
PubMed1986

Acute toxicity of brass particles to Daphnia magna.

The aquatic toxicity of brass particles was examined. Acute, 48 hour bioassays were performed using the water flea, Daphnia magna. Tests were conducted with uniform suspensions of uncoated brass particles, brass particles coated with a Teflon solution, silica particles, and titanium dioxide particles. The Teflon coating solution and the supernatant of the brass suspension (after settling of the brass) also were tested. All tests were conducted according to guidelines set forth by the US Environmental Protection Agency and the Organization for Economic Cooperation and Development. Mean EC50 determinations of 20.0 micrograms l-1 and 23.6 micrograms l-1 were calculated for uncoated brass particles and coated brass particles, respectively. The silica, titanium dioxide, and Teflon each had an EC50 greater than 1 g l-1. Chemical fate studies demonstrated that the brass dissociated to its ionic components of copper and zinc quickly at pH 2.0. At pH 5.0 and 6.5, the dissociation occurred too slowly to account for the observed toxicity. The data suggested that the toxicity is due to filtration by the daphnids and subsequent ingestion. EC50 determinations for the brass particles are nearly identical with published EC50 values for copper salts.

Alloys↗
PubMed1988

Methodological aspects of the determination of the acute inhalation toxicity of spray-can ingredients.

Spray-can ingredients, if liberated in confined spaces, are potential health hazards for man. Thus, appropriate inhalation toxicity studies have to be performed in accordance with internationally recognized guidelines, e.g. the US Environmental Protection Agency: Federal Insecticide, Fungicide and Rodenticide Act (FIFRA no. 81-3) or OECD no. 403. One of the essential requirements of such guidelines is that test animals (preferably rats) be exposed to a steady-state concentration in a dynamic inhalation chamber for at least 4 hours. This is not easy to achieve with vapours released from a pressurized spray-can. The method described here makes it possible to expose experimental animals in an inhalation chamber to a steady-state concentration of intermittently released spray jets of constant doses per jet. Animal experiments and theoretical considerations (computer simulations) have shown that the method presented allows an up-to-date determination of the acute inhalation toxicity of spray-can ingredients.

Administration, Inhalation↗
PubMedDate not supplied

Effects of organophosphates on the visual system of rats.

The possibility that exposure to organophosphate insecticides can lead to ocular damage is suggested by Japanese studies from the 1960s and 1970s indicating that exposed humans developed chronic ocular degeneration, in addition to showing more commonly accepted effects of cholinesterase-inhibiting compounds. Other papers reported ocular lesions in laboratory animals treated with organophosphates. More recently, retinal degeneration following chronic organophosphate treatment has been reported to the Environmental Protection Agency by pesticide manufacturers in studies conducted in compliance with good laboratory practice regulations. Several factors, however, have prompted scepticism regarding organophosphate-induced ocular toxicity, including the widespread use of organophosphate compounds for both agricultural and ophthalmological practices without numerous additional reports of comparable ocular toxicity. We are developing a research program to address these issues involving electrophysiological, biochemical and histological investigations of rats treated with organophosphate insecticides. The research program is young, but early results are available. Notably, retinas from rats treated with a single subcutaneous injection of 100 mg kg-1 fenthion showed decreases in carbachol-stimulated release of inositol phosphate, an indicator of cholinergically-mediated intracellular second messenger systems. These effects persisted at least 56 days after fenthion administration. This could indicate several different toxicological actions, which are currently under investigation. It is concluded that the possible association between exposure to organophosphates and ocular toxicity cannot be dismissed, and that several important research issues need to be resolved.

Animals↗
PubMedDate not supplied

Assessment of ocular toxicity in dogs during 6 months' exposure to a potent organophosphate.

Exposure to anticholinesterase pesticides has been associated with the development of ocular toxicity in humans and animals, ranging from blurred vision to degeneration of the optic nerve. Based on the concern for human safety, the US Environmental Protection Agency has recently required additional studies for this class of compounds, focusing on biochemical, functional and histopathological evaluation of the ocular system. This study was designed to determine the effects on the eye of ethyl parathion, a highly toxic organophosphate, when administered orally to 30 beagle dogs (five of each sex per group) at doses of 2.4, 7.9 or 794 micrograms kg-1day-1 for 6 months. Control animals received corn oil. Routine ophthalmoscopic and slit lamp examinations, refraction and intraocular pressure determinations and electroretinograms were performed as functional assessments at various intervals over the study. Plasma and erythrocyte cholinesterase were determined at weeks 1, 6, 14, 20 and 26, while brain, retinal and ocular muscle cholinesterase were measured at week 26 only. Histopathological examination of the retina, optic nerve, ocular muscle and ciliary body was conducted at termination. Plasma and erythrocyte cholinesterase was markedly depressed at 7.9 and 794 micrograms kg-1day-1 as early as week 1. Retinal cholinesterase was decreased (37-55%) from control values in the 794 micrograms kg-1day-1 group only. Ocular muscle cholinesterase was comparable in treated and control groups at termination. No functional impairment of the eye was noted over the 6-month study.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMedDate not supplied

Analytical mass spectrometry of herbicides.

Herbicides are chemical substances that are applied to agricultural soils, gardens, lawns, or plants to destroy or to prevent the growth of undesirable vegetation. The herbicides included in this review are generally synthetic organic compounds that are ingredients in commercial herbicide products that were designated active during late 2002 in the U.S. Environmental Protection Agency's database of registered and canceled pesticide products. The compounds are organized into 21 categories according to their general chemical structures or a common structural group. The herbicides in each category are discussed in terms of their structures, their database electron ionization mass spectra, and their amenability to separation and measurement with gas chromatography, reversed-phase liquid chromatography, and capillary electrophoresis combined with mass spectrometry. Ionization techniques that are considered here are mainly electron ionization, electrospray, and atmospheric pressure chemical ionization. Sixty-six references are provided to herbicide reviews, and to the recent herbicide analytical chemistry and mass spectrometry research literature.

Databases, Factual↗