Biomedical subjects

B E Saltzman

Publications and source records attributed to B E Saltzman.

At least 19 recordsLinked to original sources

PubMed1997

Health risk assessment of fluctuating concentrations using lognormal models.

A mathematical model is proposed for assessing health risk rates of fluctuating concentrations. Each time-averaged concentration may be regarded as a dose that, when applied to the dose-response curve, produces a risk of an adverse effect. A theoretical derivation shows that the dose-response pattern is a cumulative lognormal curve because of the diversity of the individuals in the exposed population. Similarly, the concentration pattern is a log-normal distribution because of the diversity of emission sources and dispersive processes. The health risk is produced by the overlapping of the right tail of the concentration distribution and the left tail of the dose-response curve. The evaluation of the joint probability in this region has been performed by numerical integration by computer in terms of two generalized parameters. One represents the geometric standard deviation of the concentration distribution relative to that of the dose-response curve, and the other represents the distance between the geometric mean concentration and the concentration producing an adverse response in 50% of the exposed population. These results are presented graphically and in tabular form. If the two parameters of the dose-response curve are known, the health risk of the concentration pattern may be calculated conveniently for any geometric mean and geometric standard deviation values.

Dose-Response Relationship, Drug↗

PubMed1996

Assessment of health effects of fluctuating concentrations using simplified pharmacokinetic algorithms.

The purpose of this study was to develop a simple, practical method to improve the accuracy of assessing health effects by determining the concentration patterns inside the body resulting from fluctuating external pollutant concentrations. Linear pharmacokinetic processes were assumed, and the attenuations of the high- and low-frequency components of the external pattern when entering through the "biological window" were determined. Similar attenuations also were determined for the "time-averaged sampling window." It was shown that when the averaging time was less than 1/4 of the biological half-life, no information of biological significance was lost. Thus, a simple arithmetic step equation was proposed to convert external time-averaged concentrations to "biologically effective concentrations" proportional to internal concentrations. Calculations could readily be made in real time by a monitoring instrument, or even with a pocket calculator. Another simple algorithm was proposed for determining a "biological damage parameter" representative of cumulative damage if the body repair process is slow. Finally, simple algorithms were proposed for calculating body burdens from total absorbed mass rates, a procedure that should be useful for pollutants such as lead that may enter the body through multiple pathways. Results were compared with experimental and hypothetical data to show their utility.

Air Pollutants↗

PubMed1990

Total body burdens and tissue concentrations of lead, cadmium, copper, zinc, and ash in 55 human cadavers.

Trace metal contents of human tissues and total body burdens are useful for studies of nutrition and certain diseases. Data are summarized and analyzed for individuals exposed to the normal Cincinnati environment, for 29 tissues from 55 cadavers for lead and ash concentrations, and from 26 cadavers for cadmium, copper, and zinc concentrations. Total body burdens also were calculated and correlated against each other and age. The distributions for ash, copper, and zinc were close to normal, but those for lead and cadmium were closer to lognormal. Bone lead increased with age, whereas soft tissue lead did not. The calculated mean percentage of total body lead in the bones ranged from 78% at age 20 to 96% at age 80. Correlations of blood concentrations with total body burdens were negligible for cadmium and zinc. For copper the correlation coefficient was a poor 0.54. For lead in blood vs soft tissue burden it was a very poor 0.37, and vs total body lead it was negligible. Thus the use of blood samples as a convenient clinical measure of body burdens for these metals may be of limited value. These and other findings provide a useful bank of information for health studies.

Adult↗

PubMed1988

Linear pharmacokinetic models for evaluating unusual work schedules, exposure limits and body burdens of pollutants.

The adverse effects of workplace exposures to pollutants relate more accurately to the concentrations of pollutants in the body than in the environment. In many cases pharmacokinetic models may represent the external to internal concentration relationships with useful accuracy. Simplified equations are presented for stepwise calculations on a series of time-averaged, external concentrations to give a corresponding series of internal concentrations. Accurate results were obtained for averaging times not exceeding one-fourth of the biological half-life of the pollutant. A convenient measure of internal concentration is the external concentration that would be at in vivo equilibrium with it (termed biologically effective concentration). Three measures of damage burden are proposed, each appropriate for different toxic mechanisms. The calculations readily may be carried out on a programmable calculator or microcomputer. Illustrative examples show how unusual work schedules may be compared with an 8 hr/day, 5 days/week schedule and how appropriate short- and long-term exposure limits may be determined. Other examples, illustrated for lead, relate absorbed mass rates to body concentrations and body burdens in a two-compartment kinetic model. These calculations should provide a more accurate evaluation of fluctuating concentrations, which can be handled easily.

Absorption↗

PubMed1987

Lognormal model for health risk assessment of fluctuating concentrations.

Health risk assessments of exposures to harmful materials increasingly are required because of legal and economic pressures. An important part of the procedure is the mathematical model for the dose-effects relationship. If a linear no-threshold relationship is assumed, then the mean of fluctuating concentrations may be used for the calculation of health risk. But the widely used PEL and TLV values assume a threshold relationship. For this and for nonlinear relationships the calculation with the use of the mean concentration is inaccurate, because higher concentrations produce disproportionately higher effects. An appropriate mathematical model based upon lognormal concentrations and probit effects is proposed. Rather than monitoring concentrations for unlikely high values, the method requires estimation of their geometric mean and geometric standard deviation. A health risk assessment than may be calculated simply and conveniently from the charts and tables provided. The method clarifies some issues and the specifics of utilizing and improving the required data. The model should be useful for assessing health risks from fluctuating concentrations of most toxic compounds.

Dose-Response Relationship, Drug↗

PubMed1986

Lead exposures during the segments of the ladling cycle at a non-ferrous foundry.

Explore the source record for details and available documents.

Air Pollutants, Occupational↗

PubMed1985

Variability and bias in the analyses of industrial hygiene samples.

Information on variability and bias of analyses of industrial hygiene samples is needed for quality control, for design of sampling programs, and for interpretation of results. Data was assembled from interlaboratory programs conducted by PAT-NIOSH, CDC, West Allis Memorial Hospital, and the Toxicology Center of Quebec for 12 types of samples. At the geometric mean concentrations of the reference samples the relative standard deviations of reported results were as follows: Pb, Cd, Zn on membrane filters--4.7%; solvents on charcoal tubes--6.5%; Pb in blood--(CDC) 19%, (West Allis) 13%, (Quebec) 10%; Cd in blood--52%; Cd in urine--40%; As in urine--30%; Hg in urine--25%; F in urine--13%. For free silica on membrane filters, at the geometric mean value the geometric standard deviation was 1.29. For asbestos on membrane filters the statistical analysis was made on the square roots of the values, and the range of one standard deviation was from 68% to 138% of the average value. Four methods for Pb in blood were in close agreement, but three for As in urine differed substantially. Most methods did not achieve the reproducibility required by the NIOSH criteria. The probability of false positive and negative interpretation of results from each group of participating laboratories may be calculated from these data.

Air Pollutants, Occupational↗

PubMed1983

Reproducibility and quality control in the analysis of biological samples for lead and mercury.

A simple statistical calculation was applied to 8 years of data on routine control sample and duplicate analyses from a laboratory quality control program. This provided standard deviations truly representative of this laboratory at no additional analytical expense, and accurate information on how they varied with concentrations. From these, the detection limit of the method, upper warning limits, and upper control limits for differences between duplicate analyses were calculated. These values were conveniently used for quality control in determinations of lead in blood and of mercury in urine.

Computers↗

PubMed1982

Adequacy of current industrial hygiene and occupational safety professional manpower.

Heated current political discussions of proper staffing and conduct of industrial hygiene and safety programs raise the questions of the numbers and adequacy of available professional manpower. Data from several studies of such professional manpower in the U.S. during the past decade were critically reviewed and compared. Their projected growth rates for industrial hygiene were far short of the actual recent 15%/year growth rate of AIHA membership and of ABIH diplomates, and 27% year for ABIH trainees. From these studies and census data, it was calculated that in 1977 the ratio of employees to IH professionals was 17 100, and to safety professionals 2200. Also the ratio of professional costs to the value of lost workdays plus workmen's compensation was 1.4% for industrial hygiene and 10.6% for safety. It appears likely that more IH professionals would be cost effective. Data on outputs of university training programs indicate that the majority of individuals on current staffs were not specifically trained as IH or safety professionals. Although employment demands may be affected by the outcome of ongoing political discussions, there are obvious unsatisfied needs for services. These require professional training of greater numbers than current capacities of university programs permit.

Humans↗

PubMed1981

Measurements of airborne aflatoxins during the handling of contaminated corn.

Sample of airborne dust generated the handling of aflatoxin-contaminated corn were collected and analyzed to assess potential exposures of farmers and other agricultural workers to these mycotoxins. Using high volume total dust samplers and a high volume Andersen sampler, downwind dust samples were collected on glass filter when contaminated corn was transferred by augers from a storage bin into a wagon and back into the storage bin. The aflatoxin B1 content of the 15 dust samples ranged from 12.5 to 204.3 ppb, with an average of 138 ppb; the aflatoxin B2 content ranged from 1.1 to 41.6 ppb, with an average of 24.6 ppb. The B1 and B2 levels of contamination in the bulk corn were 223.9 and 17.5 ppb, respectively. The gravimetric dust concentration in the air ranged from 7 mg/m3 to 417 mg/m3. The samples taken with an Andersen sampler indicate the dust is relatively coarse with only approximately 17% less than 7 micrometer. An analysis of the dust from each stage showed higher levels of aflatoxins in the larger first-stage particles than in the finer particles on the succeeding stages. The results of this study indicate that the dust generated when handling contaminated commodities also may be contaminated and represent a potential inhalation hazard. This fact, coupled with the extreme toxicity and carcinogenicity previously demonstrated in animal studies, suggests that appropriate measures be taken to prevent worker exposure during handling of contaminated materials.

Aflatoxins↗

PubMed1980

A comparison of heat stress indices in a hot-humid environment.

The results of a study of nine physically fit young men performing moderate exercise under various levels of hot-humid conditions are reported. Environmental stress and physiological strain data from the total of 72 test sessions were collected and computed in terms of heat stress and heat strain indices. Single and multiple factor correlation coefficients were calculated on the basis of 11 stress indices versus 4 strain indices. Most of the empirical heat stress indices correlated best with the mean skin temperature, whereas the rational indices correlated best with heart rate and sweat loss. Because of its ease of use, the WGT or the CET index may be the best choice for preliminary industrial surveys in hot-humid environments. A simple and convenient nomogram was developed on the basis of the test data relating increase in heart rate to temperature, humidity, and air velocity.

Adult↗

PubMed1980

The development of an air sampling and analytic method for o-phenylenediamine in an industrial environment.

A new method for monitoring o-phenylenediamine (OPD) in the industrial environment was developed. Some aromatic amines such as OPD are difficult to collect and analyze directly because they are sensitive to oxidation. The method developed overcomes this difficulty by derivatizing the OPD directly upon collection. The OPD vapor is drawn through a bubbler containing acetic anhydride to form the relatively stable 1,2-diacetamidobenzene. The acetic anhydride solution is analyzed by means of high performance liquid chromatography (HPLC), and the diacetamido derivative quantified. The analysis is linear for standard solutions in the range of 0.5 microgram/mL to over 0.5 mg/mL. Air concentrations of OPD were prepared by passing a metered stream of nitrogen through a class tube packed with OPD crystals and diluting the stream with a metered air stream to achieve the desired level. The collection efficiency and conversion of OPD to the derivative was found to approach 100% at vapor concentrations of 0.09 mg/m3 but was reduced to about 60% at 0.02 mg/m3. The poor recovery at low concentrations appeared to be at least in part due to wall adsorption. Moisture had little effect on sample collection and analysis. O-Toluenediamine, chemically similar to OPD, was found to interfere in the analysis.

Absorption↗

PubMed1979