Frequency Distributions Of Concentrations Research Articles

LEVELS OF CADMIUM IN KIDNEY AND LIVER TISSUES AMONG A CANADIAN POPULATION (PROVINCE OF QUEBEC)

In an exploratory study, levels of cadmium in whole-kidney and liver tissues of 314 subjects from the general population of the province of Quebec (Canada) were measured postmortem. Frequency distributions of cadmium concentrations were lognormal. As reported in similar studies, age and especially smoking habits were the main variables affecting cadmium concentrations. The geometric mean of whole kidney concentrations (wet weight) was 17.62 mug/g, with a minimum concentration of 2.25 mug/g and a maximum of 100.61 mug/g. Mean concentrations of cadmium in kidneys increased with age, reaching a plateau in the group 50 to 59 yr (29.49 mug/g), and falling slowly thereafter.

Prediction of illness risk near ocean outfalls using frequency distributions of bacterial concentrations

Water quality managers traditionally assess the illness risk associated with indicator bacteria in bathing waters by comparing an average concentration to a concentration standard, where the average may be determined from a frequency distribution of concentrations. The United States EPA concentration standards are determined as the concentration which gives an acceptable illness rate according to a mathematical relation between the concentration and illness rate (concentration–response relation). However, further use can be made of the frequency distribution and concentration–response relation. This paper presents a method for combining the temporal concentration frequency distribution with a concentration–response relation to obtain the averaged illness rate (that is, the expected illness rate). First the method is developed for the concentration frequency distribution at a single location. The method is also extended for the case where the temporal concentration frequency distribution is known at a number of points throughout the area in the vicinity of the outfall, in which case spatial contours of averaged illness rate can be determined. The methods are demonstrated for a site at the North Shore, New Zealand.

Sex steroids, growth and condition of Arctic charr broodstock during an annual cycle

Changes in plasma concentrations of sex steroids, growth rate and condition of repeat spawning (3+) male and female Arctic charr were studied throughout an annual reproductive cycle. Individually marked fish (mean weight approx. 500 g) were held under conditions of liberal food supply, constant temperature (4° C) and simulated natural photoperiod (Tromsø, 70° N). Once each month fish were weighed, measured and blood samples taken for steroid analysis. Plasma concentrations of testosterone (T), 11‐ketotestosterone (11‐KT) and oestradiol‐17β (E2) were determined using radioimmunoassay (RIA). Both male and female fish displayed distinct seasonal changes in plasma concentrations of sex steroids, growth rate and condition. From February (minimal concentrations) to March all sex steroids increased slightly and these elevated concentrations were maintained until May. Thereafter, there was a second, and far more pronounced, increase in plasma steroid concentrations which culminated in peak steroid concentrations in September–October. There was then a rapid decline during the spawning period. In winter, growth rate and condition were generally low, then increased during the spring, reached a peak during the summer, and then declined with the onset of autumn. During spring (March–May), the frequency distributions of plasma testosterone concentrations in both male and female fish were bimodal. The fish of the upper modal group of the distribution had significantly higher growth rates and condition than those in the lower modal group. In summer and early autumn (June–September) the association between T and growth rate changed. Significant negative correlations between T and growth rates were observed in females. There was an increase in endocrine activity, indicated by elevated plasma sex steroid concentrations in March, 7–8 months prior to maturation. It is suggested that this may be one factor influencing the onset of spring growth and energy deposition among maturing charr.

Sex steroids, growth and condition of Arctic charr broodstock during an annual cycle

Changes in plasma concentrations of sex steroids, growth rate and condition of repeat spawning (3+) male and female Arctic charr were studied throughout an annual reproductive cycle. Individually marked fish (mean weight approx. 500 g) were held under conditions of liberal food supply, constant temperature (4° C) and simulated natural photoperiod (Tromsø, 70° N). Once each month fish were weighed, measured and blood samples taken for steroid analysis. Plasma concentrations of testosterone (T), 11-ketotestosterone (11-KT) and oestradiol-17β (E2) were determined using radioimmunoassay (RIA). Both male and female fish displayed distinct seasonal changes in plasma concentrations of sex steroids, growth rate and condition. From February (minimal concentrations) to March all sex steroids increased slightly and these elevated concentrations were maintained until May. Thereafter, there was a second, and far more pronounced, increase in plasma steroid concentrations which culminated in peak steroid concentrations in September–October. There was then a rapid decline during the spawning period. In winter, growth rate and condition were generally low, then increased during the spring, reached a peak during the summer, and then declined with the onset of autumn. During spring (March–May), the frequency distributions of plasma testosterone concentrations in both male and female fish were bimodal. The fish of the upper modal group of the distribution had significantly higher growth rates and condition than those in the lower modal group. In summer and early autumn (June–September) the association between T and growth rate changed. Significant negative correlations between T and growth rates were observed in females. There was an increase in endocrine activity, indicated by elevated plasma sex steroid concentrations in March, 7–8 months prior to maturation. It is suggested that this may be one factor influencing the onset of spring growth and energy deposition among maturing charr.

Fingerprinting urban kerbside carbon monoxide concentrations: interaction between street grid configuration, vehicle flows and local wind effects

Up to now, little has been understood about the way that airborne pollution is distributed spatially at head height and kerbside in the urban Street grid. This paper reports on research in which a new monitor has been developed, validated and used to sample a small urban neighbourhood at finer temporal and spatial resolutions than has been achieved previously. The data show that pollution concentrations at head height vary radically within metres of each other. A method is developed for using the shape of the frequency distribution of pollutant concentrations to "fingerprint" monitoring sites in terms of their pollution exposure at both average levels and at the extremes, and to compare the effects of climatic, seasonal and diurnal changes on pollution concentrations, as well as to help isolate effects of traffic management and other interventions on local ambient pollution concentrations. "Space syntax" methods of analysis of street grid configuration, which have been shown to predict vehicular flows on the basis of representations of the geometry and topology of the Street grid alone, were found to predict both average and extreme CO concentrations (r = 0.88, p = 0.0001) at Street segment resolution in the urban grid.

Applicability of gold as an atmospheric aerosol tracer

The present paper describes a method to determine the gold content of samples of atmospheric particulate matter. Both integral filter samples as well as size-segregated impactor samples are accessible to the method. Results of the analysis of 29 filter samples and three size-segregated impactor samples, taken at Ispra in Northern Italy, are reported. The frequency distribution of the gold concentrations can be described by a long-normal distribution with a geometric mean concentration of 23.2 pg m −3 and a geometric standard deviation of 2.1. The method is validated by the analysis of a certified reference material, for which a mean recovery of gold of 78% was obtained. Based on the variability of the gold concentration in atmospheric aerosol, the maximum distance to which gold as a tracer can be quantified, assuming specific meteorological conditions, is estimated by means of the Gaussian Dispersion Model. Using Pasquill Stability Classes to characterize atmospheric stability, this distance is 33 and 104 km for stability classes C and D, respectively, for a release of 65 g of gold. References to other tracer experiments are given.

Liprotein(a) Phenotypes in Japanese Children: A Cohort Study

Elevated serum lipoprotein(a) [Lp(a)] concentrations have been demonstrated to be associated with cardiovascular diseases due to premature atherosclerosis. However, the association of Lp(a) phenotypes with the development of these diseases remains largely unexplored. We analyzed the population-based frequencies of serum Lp(a) phenotypes in 269 Japanese children aged 8-13 years in one community. According to the different apolipoprotein(a) [apo(a)] electrophoretic mobilities, Lp(a) was classified into seven single-band and respective double-band phenotypes. Each individual expressed a single (homozygotic) or a double band (heterozygotic). The serum Lp(a) concentration frequency distribution was skewed toward lower levels with a mean +/- SD of 15.5 +/- 18.0 mg/dl and a median of 11.0 mg/dl. The Lp(a) phenotype frequencies revealed that the frequency of double-band phenotype expression (55%) was higher than that of single bands (44%) and that the frequency of phenotypes representative of low molecular weight apo(a) was very low (2%). The mean serum Lp(a) concentration of the double-band-expressing subjects was higher than that of subjects with the single-band phenotype (20.1 +/- 19.9 vs. 10.5 +/- 15.9 mg/dl, p < 0.01). These findings of Lp(a) phenotypes in children seemed to differ from those in Japanese adults in another study; contrary to expectation, the predominant Lp(a) phenotypes found in children were those frequently associated with cardiovascular diseases in adults. Thus, it is speculated that children whose Lp(a) phenotypes remain unchanged during the transition to adulthood may show an increased susceptibility to cardiovascular disease, although the nutritional effects on the Lp(a) phenotypes cannot be neglected.

Lognormal distribution of natural radionuclides in freshwater sediments and coal-ash repositories

The distribution of natural radionuclides,40K,226Ra, and232Th, in freshwater sediments and in coal-fired power-plant ash repositories has been tested for lognormality. Thereafter, lognormality for natural radionuclide concentration frequency distribution was accepted with a high probability. The lognormal natural radionuclide distribution in sediments and coal-ash indicated single population groups. The anthropogenic modifications of the natural radionuclide concentrations in the environment are indicated. The adsorbed dose rates, in mGy y−1, in air from gamma field of the natural radionuclides were calculated.

Multiparametric classification of trophic conditions. The OECD methodology extended: combined probabilities and uncertainties — application to the North Adriatic Sea

A new approach to trophic classification of water bodies, based on combining the exact probabilities from the OECD (Organization for Economic Cooperation and Development) lognormal frequency distributions of chlorophyll, nitrogen, and phosphorus concentrations and Secchi depths, is presented, using a sample data set from monitoring activities carried out in the North Adriatic Sea in the summer of 1992. This probabilistic approach is shown to be effective in solving uncertain or even contradictory classifications which may often arise from membership probabilities, based on single sample variables, as in the present OECD system. Such an extension to multiparametric sample space is open to possible modifications of trophic variables, and allows comparisons among samples with inhomogeneous or even unmatching types of measurements. Classification uncertainties, caused by the uncoupling of trophic variables, are shown to be related to environmental disturbances given by discharges, inflows and turbulent diffusion. Their role in trophic classification procedures, and environmental importance and meaning is stressed in relation to the applicability of the extended OECD methodology to non-steady state systems.

95/05360 Mutagenicity of exhaust gas from incineration plants of municipal waste

Specimens of mussels (Mytilus edulis), winkles (Littorina littorea), dogwhelks (Nucella lapillus) and limpets (Patella vulgata) were collected from the north-east coast of England in 1980–1981 in order to analyse the dried whole soft tissue for zinc, copper and iron. In each case, only a narrow size range of organisms was collected from a small environmentally homogeneous site and sex was taken into account. Most of the frequency distributions of metal concentrations obtained were found to show significant positive skewness. This skewness could not be explained either by the degree of mobility or type of feeding mechanism of the organisms or by any other known parameter, e.g. size, sex, habitat variation. Some individual mussels were found to be extremely good regulators of their zinc concentrations. On the other hand, other individual mussels had the ability to accumulate unusually high levels of zinc.

Andrology: Polycystic ovary syndrome: the spectrum of the disorder in 1741 patients

The criteria for the diagnosis of the polycystic ovary syndrome (PCOS) have still not been agreed universally. A population of 1741 women with PCOS were studied, all of whom had polycystic ovaries seen by ultrasound scan. The frequency distributions of the serum concentrations of follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone and prolactin and the body mass index, ovarian volume, uterine cross-sectional area and endometrial thickness were determined and compared with the symptoms and signs of PCOS. Obesity was associated with hirsutism and an elevated serum testosterone concentration and was also correlated with increased rates of infertility and cycle disturbance. The rates of infertility and cycle disturbance also increased with serum LH concentrations > 10 IU/l. A rising serum concentration of testosterone [mean and 95th percentiles 2.6 (1.1-4.8) nmol/l] was associated with an increased risk of hirsutism, infertility and cycle disturbance. The ovarian volume was correlated with serum concentrations of testosterone, LH and the body mass index, which was also correlated with the uterine area. This descriptive data from the largest reported series of women with PCOS enables the development of a management-orientated approach to the syndrome. Women who are overweight can expect an improvement in their symptoms if they lose weight. An elevated concentration of LH (> 10 IU/l) is associated with infertility and treatment should be chosen accordingly. If the serum testosterone concentration is > 4.8 nmol/l, other causes of hyperandrogenism should be excluded.

Application of the EU bathing water directive to the design of marine sewage disposal systems

A mathematical model for the design of marine sewage disposal systems in accordance with the criteria of the EU Bathing Water Directive is developed and applied to the design of the outfall of the sewage from Athens, Greece. The model calculates the reduction of fecal coliforms due to initial and subsequent dilutions and die-off due to the effect of solar radiation and predicts the concentrations of fecal coliforms at the bathing area for specific hours and current velocities. A combination of these results with the probability distribution of the velocity of the sea currents results in a frequency distribution of fecal coliform concentrations at the bathing area, thus enabling evaluations with respect to conformity to the statistical criteria of the EU Directive. The application of the model to the disposal system for the sewage of Athens shows that conformity, without the use of effluent disinfection, can be achieved for the nearest bathing area, located at a distance of 3.4 km from the outfall, irrespective of the definition of the bathing hours (8 am-8 pm or 24 hrs) and for a sufficiently conservative mortality rate. These results indicate that under Mediterranean or similar conditions, with typical wind induced currents, a sewage field travel distance of a few kilometres is sufficient to ensure bathing areas against infection, without the need for sewage disinfection. It should, however, be stressed that these conclusions are valid on the assumption that the sampling procedures outlined in the EU Directive refer to uniformly distributed sampling throughout the bathing period of the day or season.

An open‐air system for exposure of young forest trees to sulphur dioxide and ozone

ABSTRACTThe development, construction and operation of an open‐air fumigation system for exposing young forest trees to controlled concentrations of sulphur dioxide and ozone is described. A computer simulation of gas dispersion was used to design an array of pipework sources which minimized spatial variability in exposure concentrations. Five fumigation plots were constructed using the design and were used to fumigate trees during a 7 year study known as the Liphook Forest Fumigation Project. Rates of gas release were controlled by a small computer to follow predetermined patterns of sulphur dioxide concentration and to maintain an elevation above ambient ozone concentration. Effective control of exposure was demonstrated, and examples of experimentally produced concentration frequency distributions are provided. The advantages and shortcomings of the system are discussed with recommendations for future improvements.

Ion transport in primary cultures from human sweat gland coils studied with X-ray microanalysis

Chloride secretion in primary cultures of cells originating from the secretory coil of human sweat glands was investigated by electron probe X-ray microanalysis. The total intracellular Cl concentration was lowered by muscarinic agonists (carbachol and acetylcholine), as well as by the calcium ionophore A23187. The muscarinic agonists also lowered the cellular K concentration. Cl - secretion induced by these agonists could be inhibited by the chloride channel blocker NPPB. After cAMP stimulation, the frequency distribution of the Cl concentration changed from Gaussian to bimodal, indicating that cAMP induces Cl - secretion only from a subpopulation of the cells. Also ATP stimulated Cl - secretion, indicating the presence of purinergic receptors. The results suggest that some of the cells in addition to Ca 2+ -regulated Cl - channels also possess cAMP-activated Cl - channels. Hence, the primary cultures still possess the Cl - transport mechanisms known to be present in intact glands. It can, however, not be excluded that some coil cells have acquired ductal characteristics during culture.

Application of the eu bathing water directive to the design of marine sewage disposal systems

A mathematical model for the design of marine sewage disposal systems in accordance with the criteria of the EU Bathing Water Directive is developed and applied to the design of the outfall of the sewage from Athens, Greece. The model calculates the reduction of fecal coliforms due to initial and subsequent dilutions and die-off due to the effect of solar radiation and predicts the concentrations of fecal coliforms at the bathing area for specific hours and current velocities. A combination of these results with the probability distribution of the velocity of the sea currents results in a frequency distribution of fecal coliform concentrations at the bathing area, thus enabling evaluations with respect to conformity to the statistical criteria of the EU Directive.The application of the model to the disposal system for the sewage of Athens shows that conformity, without the use of effluent disinfection, can be achieved for the nearest bathing area, located at a distance of 3.4 km from the outfall, irrespective of the definition of the bathing hours (8 am–8 pm or 24 hrs) and for a sufficiently conservative mortality rate. These results indicate that under Mediterranean or similar conditions, with typical wind induced currents, a sewage field travel distance of a few kilometres is sufficient to ensure bathing areas against infection, without the need for sewage disinfection. It should, however, be stressed that these conclusions are valid on the assumption that the sampling procedures outlined in the EU Directive refer to uniformly distributed sampling throughout the bathing period of the day or season.

National and Regional Distributions of Airborne Radon Concentrations in U.S. Homes

The National Residential Radon Survey was conducted during 1989 and 1990 to provide data on the frequency distribution of annual average radon concentrations in U.S. residences nationwide, in U.S. Environmental Protection Agency defined Regions, and in subgroups of the housing stock. The National Residential Radon Survey also provided housing and demographic data and a preliminary assessment of the relationship of housing and geographical characteristics to residential radon concentrations. This paper focuses solely on the national and regional estimates of annual average radon concentrations. A stratified, three-stage sampling procedure was used to select housing units for the survey. Data were collected through personal interviews with residents and placement of alpha track detectors in each level of the residences for 12 mo. The survey found an arithmetic annual average radon concentration in U.S. homes of 46.3 +/- 4.4 Bq m-3 (1.25 +/- 0.12 pCi L-1). About 6.0 +/- 1.4% of homes (5.8 million) had radon levels greater than the U.S. Environmental Protection Agency's action level for mitigation of 148 Bq m-3 (4 pCi L-1). Concentrations varied significantly across Environmental Protection Agency Regions. A lognormal distribution was found to closely approximate the major distributions of radon concentrations.

Long-term air quality statistics derived from wind-tunnel investigations

Wind-tunnel investigations are commonly used to determine pollutant concentrations in the vicinity of buildings. Results of these investigations should be comparable and compatible with the format used to express air quality standards. An analysis method for wind-tunnel data is proposed which enables the calculation of the frequency distribution of pollutant concentrations which is compatible with the Dutch “National Model”. The outcome is long-term averaged concentrations as well as percentile values based on 1-h averaged concentrations. The method takes into account the lack of horizontal meandering in the wind tunnel compared to the real atmosphere and the effect of wind speed.

Evolution of southern hemisphere spring air masses observed by HALOE

The evolution of Southern Hemisphere air masses observed by the Halogen Occultation Experiment (HALOE) during September 21 through October 15, 1992, is investigated using isentropic trajectories computed from United Kingdom Meteorological Office (UKMO) assimilated winds and temperatures. Maps of constituent concentrations are obtained by accumulation of air masses from previous HALOE occultations. Lagged correlations between initial and subsequent HALOE observations of the same air mass are used to validate the air mass trajectories. High correlations are found for lag times as large as 10 days. Frequency distributions of the air mass constituent concentrations are used to examine constituent distributions in and around the Southern Hemisphere polar vortex.

Ambient ozone and crop loss: Establishing a cause-effect relationship

This paper provides the results of a retrospective mathematical analysis of the US NCLAN (National Crop Loss Assessment Network) open-top chamber data. Some 77% of the 73 crop harvests examined, showed no statistically significant yield differences between NF (non-filtered open-top chamber) and AA (chamberless, ambient air) treatments (no easily discernable chamber effects on yield). However, among these cases only seven acceptable examples showed statistically significant yield reductions in NF compared to the CF (charcoal filtered open-top chamber) treatment. An examination of the combined or cumulative hourly ambient O 3 frequency distribution for cases with yield loss in NF compared to a similar match of cases without yield loss showed that the mean, median and the various percentiles were all higher (≥ 3 ×) in the former in contrast to the latter scenario. The combined frequency distribution of hourly O 3 concentrations for the cases with yield loss in NF were clearly separated from the corresponding distribution with no yield loss, at O 3 concentrations > 49 ppb. Univariate linear regressions between various O 3 exposure parameters and per cent yield losses in NF showed that the cumulative frequency of occurrence of O 3 concentrations between 50 and 87 ppb was the best predictor (adjusted R 2 = 0.712 and p = 0.011). This analysis also showed that the frequency distribution of hourly concentrations up to 87 ppb O 3 represented a critical point, since the addition of the frequency distributions of >87 ppb O 3 did not improve the R 2 values. In fact as the frequency of hourly O 3 concentrations included in the regression approached 50–100 ppb, the R 2 value decreased substantially and the p value increased inversely. Further, univariate linear regressions between the frequencies of occurrence of various O 3 concentrations between 50 and 90 ppb and: (a) cases with no yield difference in NF and (b) cases with yield increase in NF compared to the CF treatment (positive effect) provided no meaningful statistical relationship (adjusted R 2 = 0.000) in either category. These results support the basis that additional evaluation of the frequency of occurrence of hourly O 3 concentrations between 50 and 87 ppb for cases with the yield reductions could provide a meaningful ambient O 3 standard, objective or guideline for vegetation.

Concentrations of acetone in venous blood samples from drunk drivers, type-I diabetic outpatients, and healthy blood donors.

Headspace gas chromatography (HSGC) was used to measure the concentrations of acetone in samples of venous whole blood from drunk drivers (n = 500), hospital outpatients with type-I diabetes mellitus (n = 250), and healthy blood donors (n = 288). The standard deviation (SD) of blood-acetone determination by HSGC was 0.048 mg/L at a mean concentration of 2.34 mg/L (2.1%). The concentration of acetone in blood did not change significantly when the samples were stored at 4 degrees C for eight days. The ratio of the concentrations of acetone in plasma and whole blood was 1.23:1 (SD 0.229, n = 22). The frequency distributions of blood-acetone concentrations were markedly skewed to the right. The median concentration of acetone in blood from drunk drivers was 2.03 mg/L and the 2.5 and 97.5 percentiles were 0.80 and 12.8 mg/L, respectively. In patients with type-I diabetes mellitus, the median blood-acetone concentration was 1.90 mg/L and the 2.5 and 97.5 percentiles were 0.40 and 11.1 mg/L, respectively. In healthy blood donors, the median blood-acetone level was 1.26 mg/L and the 2.5 and 97.5 percentiles were 0.37 and 4.69 mg/L, respectively. The concentrations of acetone in blood did not differ appreciably among these three groups of subjects.