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At least 631 records · Page 35Linked to original sources
PubMed1992

[Factors which may mask a possible safe threshold for asbestos fibre].

Five factors are identified which could mask a possible threshold for asbestos fibre as a cause of asbestosis: (i) the definition of asbestosis; (ii) the influence of dust other than asbestos fibre; (iii) the underestimation of the true exposure to fibres; (iv) the non-allowance for random error in the determination of disease; and (v) the overestimation of early (high) exposures coupled with the underestimation of later (low) exposures. The manner in which each of these factors may tend to mask the existence of a threshold is dealt with. It is concluded that one or more of the factors could have been responsible for some of the unsuccessful past attempts to demonstrate a safe concentration for asbestos fibre. It is recommended that in future, exposure-response studies should take these factors into account.

Asbestos↗
PubMedDate not supplied

Determination of sulfadimethoxine withdrawal time from milk. Part II: Statistical assessment.

A statistical method is proposed to establish milk discard time for the data set described in Part I (preceding paper). Results are compared with those from the Food and Drug Administration (FDA)-recommended method. The milk discard time is established on the basis of a calculated tolerance limit. This limit provides 95% confidence that 99% of the population residue would assay below the permitted concentration (10 ppb for SDM). Unlike the FDA method, the proposed method allows easy calculation and requires no assumptions in drug depletion rate over time. For a permitted concentration of 10 ppb, both methods confirm the present 60-h discard time for SDM when it is assumed that no more than 1/3 of the milk came from treated cows.

Animals↗
PubMed1996

Copper in drinking water--an investigation into possible health effects.

A study was carried out to examine the possible relationship between levels of copper in drinking water and the incidence of specified childhood liver complaints presenting at a major UK paediatric liver unit. Public drinking water supplies were generally found to have levels of copper which were well below the EC standard of 3,000 micrograms/l. In private supplies, a slightly greater number of samples were found to exceed the prescribed concentration; in one instance a value of 26,000 micrograms/l was recorded. Data describing infant patients reporting to Kings College Hospital, London with specified liver complaints were examined. Where the address of patients could be determined (220 out of 240 cases), all patients were found to live in areas served by public drinking water supplies and were, thus, unlikely to have experienced elevated drinking water copper concentrations.

Child↗
PubMed2001

Time trends in exposure measurements from OSHA compliance inspections of the pulp and paper industry.

Time trends in employee exposures to the air contaminants measured by the Occupational Safety and Health Administration (OSHA) during compliance inspections of pulp and paper manufacturing facilities conducted between 1979 and 1997 were evaluated based on the measurement results stored in the OSHA Integrated Management Information System (IMIS) database. The IMIS database is among the largest sources of occupational exposure measurements available for occupational health research in the United States. The IMIS database contains the results of 3,568 personal time-weighted average (TWA) measurements for 171 air contaminants made at 524 establishments in Standard Industrial Classification (SIC) 26. An analysis of these measurements revealed an overall decrease in the total number of measurements made per year since 1991, and a decrease in the percentage of measurements by year that exceeded the OSHA permissible exposure limits (PELs). Linear regression analyses detected decreasing trends in the geometric mean concentrations by year for 33 of the 36 agents analyzed.

Air Pollutants, Occupational↗
PubMed2002

Pesticide residues in thermal mineral water in Greece.

Eight different hot springs (SPA) in Greece were monitored over a one-year survey for priority pesticide residues. A specific and effective procedure including solid phase extraction in combination with HPLC and GC analytical methods were applied. Samples that were sensitive to nitrogen-phosphorus (NPD) and/or electron capture (ECD) detectors were analysed by capillary gas chromatography. From the twenty-six water samples, pesticide residues were detected in fourteen of them (54%) but no one exceeding the European Union Maximum Acceptable Concentration (MAC). Lindane (gamma-BHC) was the most frequently detected pesticide. It was found in nine samples (35%) in concentrations from < 0.005 to 0.01 microg/L. Other pesticides detected were phorate (in five samples), propachlor (in two samples) and chlorpyriphos ethyl (in three samples) but in concentrations far below the permissible levels.

Chromatography, Gas↗
PubMed1994

Establishing generic remediation goals for the polycyclic aromatic hydrocarbons: critical issues.

Polycyclic aromatic hydrocarbons (PAHs) were one of the first classes of compounds identified as carcinogens and are often chemicals of concern at hazardous waste sites. Remediation goals established by regulatory agencies for carcinogenic PAHs in soil are generally either risk based or based on the method detection limits. PAHs are products of incomplete combustion, are components of petroleum, and as such, are prevalent in the environment from both natural and anthropogenic sources. Background concentrations are often above risk- or detection limit-based criteria, and therefore these remediation goals are of limited practical use as target criteria. In addition, the approaches used to establish target criteria do not account for several factors that may produce over- or underestimates of risk associated with the PAHs. Because of the frequency with which these compounds are detected, it is imperative that reasonably achievable and practical remediation goals be established. This paper examines the various factors that contribute to over- and underestimates of risks associated with PAHs and presents an approach for establishing cleanup criteria that takes into account health risks, background concentrations, and achievability.

Carcinogens, Environmental↗
PubMed1975

Estimating "safe" levels, a hazardous undertaking.

Various problems beset the question of identifying chemical carcinogens in the environment or setting permissible levels for potential carcinogens. Issues arising are cost-benefit questions, existence of thresholds, appropriate experimental designs, how to extrapolate to man, results from tests on laboratory animals, etc. Certain approaches implicitly involve use of a double standard, with much more stringent measures taken when clearer evidence of carcinogenicity is found. Such double standards may discourage careful testing of carcinogens as this could more probably lead to imposition of the stricter measure. Even-handed application of devices like that recommended by Mantel and Bryan for setting "safe" levels could avoid this difficulty and would encourage more adequate testing. Why laboratory testing should be at high or moderately high levels is explained and the futility of "mega-mouse" experiments at very low dose levels is indicated. A surface-area rule for extrapolating dose levels from laboratory animal to man is suggested, but this is indicated to lead approximately to direct equivalence when dose levels are expressed as dietary concentrations.

Animals↗