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PubMed1990

[Substantiation of the mean working day maximum allowable concentrations of dusts with differing degrees of fibrogenesis].

On the basis of developed by the author mathematical models of pneumoconiosis morbidity and of methodological techniques of dusts dividing according to the degree of fibrogenesis under exposure to various concentrations of dusts differing in fibrogenesis. In the author's opinion, working conditions can be considered safe if the probability of pneumoconiosis does not exceed 0.1% for the 40 years length of working. On this basis mean working day concentrations, at which the probability of the development of the mentioned disease does not exceed 0.1%, are proposed as mean working day MACs. Average working day MACs for the whole range of dusts fibrogenesis have been calculated. The obtained in this way average working day MACs for the least fibrogenic dusts equal 6 mg/m3, and for the most fibrogenic dusts - 0.2 mg/m3.

Air Pollutants, Occupational↗
PubMed1991

[Data for the establishment of maximum allowable concentration of chlorophenoxypinacoline in the working zone air].

Chlorophenoxypinacoline with its acute intragastric toxicity LD50 can be attributed to the 3rd class compounds of hazardousness (moderate hazardous substances). Local irritation and skin resorption effects were not revealed. Irritation of the mucous in the eyes in rabbits was moderate and functional cumulation was insignificant. Average lethal concentration (LC50) was not attained. The threshold of acute inhalation and irritation action (Limac, Limir) was at 1093 mg/m3, the threshold of chronic inhalation action (Limch) was at 165.2 mg/m3. No signs of specific mutagenic and embryotropic action were found. The accepted MAC for chlorophenoxypinacoline in the working zone air is 10 mg/m3. The aggregate condition aerosol, 3rd degree of hazardousness.

Air Pollutants, Occupational↗
PubMed1997

[Problems associated with setting maximum allowable concentrations (MAC) of harmful substances present in the work environment].

The major aim of setting MAC values is to reduce the risk of occupational exposure to harmful substances to the acceptable level. In the process of setting MAC values, a critical analysis of the toxicological and medical literature, used by teams of experts who try to estimate the probability of health effects with different concentrations and different duration of exposures, is most essential. This process is usually very difficult since the epidemiological data and the results of animal experiments are often incomplete, and extrapolation of experimental results from animals to humans entails a lot of doubts. Moreover, one never knows which level of the risk can be considered as acceptable. That is why MAC values set by groups of experts cannot be treated as absolutely safe to the human health. They should be verified if new data on biological effect of substances harmful to health and new criteria for occupational risk assessment become available.

Animals↗
PubMedDate not supplied

Case study of groundwater pollution in a critical area of the Southern-Friuli exposed to agricultural and landfill pressures.

Groundwater of the Southern-Friuli displays high levels of agricultural pollutants, such as nitrates and triazinic herbicides not only in the surficial layers, but also in the deeper ones, below 150 m. Some wells of the district of Gonars was monitored. The examined waters, used for irrigation but also for drinkable use, are exposed to environmental risk due to both agricultural practices and presence of many waste disposal sites. Heavy metals, nitrates and triazinic herbicides were measured in samples taken at four wells in three periods having different rain conditions. We found that groundwater quality is affected mainly by agricultural practices: nitrates and triazines are present at levels very near as well as superior to the maximum concentration allowable by Italian law. These agricultural contaminants have similar levels at all sampled sites: no difference was detected between dry periods and rain ones. Heavy metal contents are negligible in all cases; this fact suggests that ion-exchange, sorbing and complexing properties of the soils hinder the way of the metal leachates towards underlying groundwater. Zinc constitutes an exception; it is found at levels near or superior to the maximum allowable concentration (CMA), and the highest contents are observed in rain periods; different sites display different zinc levels, suggesting that this metal could have various point sources. Nitrates fertilisers were found in all sites at similar levels, very near to CMA (50 mg/L). Triazines are specific herbicides for corn growing, highly diffused here: their use in recent years is forbidden by Italian law, but the presence in groundwater of parent triazines and metabolites is a persistent problem of this area. The Italian law indicates a CMA of 0.10 microgram/L for the sum of atrazine and desethylatrazine, but we found that desethylatrazine by itself exceeds largely CMA in all sites.

Agriculture↗
PubMed2002

A general classification of water quality in Indian context.

Water quality criteria are developed on the basis of scientific information about the effects of pollutants upon a specific use of water. The criteria, therefore, are defined as the acceptable levels of concentrations of pollutants for a particular use and describe the water quality requirements for protecting aquatic biota and maintaining an individual water use e.g. drinking, bathing, irrigation, industrial etc. Various international and national agencies have defined water quality criteria for different uses of water in tropical/non-tropical regions e.g. European Community (EC) standards have been developed specifying the Guide Level and Maximum Admissible Level of pollutant concentration for three different uses of water vis-a-vis drinking, bathing and fish water. WHO standards are defined in terms of a Action Level, whereas, WQIHS, Teharan have defined standards as Acceptable Concentrations and Maximum Allowable Concentrations. In India, CPCB has defined five classes A to E specifying different levels of treatment required to these class of water for different uses such as drinking outdoor bathing, propogation of wildlife and fisheries, and irrigation and industrial cooling. Mostly the water quality parameters considered in defining these standards are pH, Temperature, Turbidity chlorides, SO4 NO3, BOD, DO, TDS, coliform and some of the important heavy metals. However, many other parameters are also considered by the individual agencies. Thus, it is seen that different agencies use different terminology for classification such as Guide Level, Action Level, Maximum Allowable Concentration and Acceptable Level etc. for defining the water quality criteria. Hence, it was felt that a common classification such as Excellent, Acceptable, Slightly Polluted, Polluted and Heavily Polluted water, is essential to know the water quality status. In this context, an attempt is made to define a common platform of water quality classification as given above considering the important indicator parameters and the standards suitable for Indian scenario. The CPCB criteria for different parameters has been given due consideration while defining the concentration levels in the newly defined classes. The parameters/classes for which criteria were not defined in CPCB standards, reference was made to the standards defined by other agencies. To each one of these classes integer values was assigned in geometric progression which indicate the level of pollution in numeric terms. These values were termed as class indices and form the basis for comparison of water quality from Excellent to heavily polluted. The mathematical expressions were fitted to concentration ranges/levels in each of these classes against the class index. Thus, given a set of observations on water quality in terms of the parameters considered in this work, the mathematical expressions for that parameter gives a numerical value indicating the status of water quality Excellent, Acceptable, Slightly Polluted, Polluted or Heavily Polluted water.

Humans↗
PubMed1999

A comparison of minimum detectable and proposed maximum allowable soil concentration cleanup levels for selected radionuclides.

Regulations on the release of a radioactively contaminated site for unrestricted use are currently being established by the Environmental Protection Agency. The effective dose equivalent rate limit for the reasonably maximally exposed individual was proposed at 0.15 mSv y(-1). The purpose of this study is to investigate whether or not maximum allowable soil concentrations of common radionuclides corresponding to 0.15 mSv y(-1) are readily detectable. These maximum allowable soil concentrations were estimated using RESRAD. The RESRAD estimates account for an effective dose equivalent rate from external radiation plus the committed effective dose equivalent rate from internal radiation delivering 0.15 mSv y(-1) to the reasonably maximally exposed individual. For Michigan and Arizona soil, the minimum detectable activities were calculated for a few radionuclides and compared to the RESRAD estimated maximum allowable concentrations. Considering only gamma-ray spectroscopy, this study found no evidence that concentrations of gamma-ray emitting radionuclides in soil contributing to 0.15 mSv y(-1) were undetectable.

Arizona↗
PubMed2001

Predicting groundwater nitrate concentrations in a region of mixed agricultural land use: a comparison of three approaches.

We investigated whether nitrate-N (NO3(-)-N) concentrations of shallow groundwater (< 30 m from the land surface) in a region of intensive agriculture could be predicted on the basis of land use information, topsoil properties that affect the ability of topsoil to generate nitrate at a site, or the 'leaching risk' at different sites. Groundwater NO3(-)-N concentrations were collected biannually for 3 years at 88 sites within the Waikato Region of New Zealand. The land use was classed as either the predominant land use of the farm where the well or bore was located, or the dominant land use within a 500 m radius of the well or bore. Topsoil properties that affect the ability of soil to generate nitrate were also measured at all the sites, and a leaching risk assessment model 'DRASTIC' was used to assess the risk of NO3(-)-N leaching to groundwater at each site. The concentration of NO3(-)-N in shallow groundwater in the Waikato Region varied considerably, both temporally and spatially. Nine percent of sites surveyed had groundwater NO3(-)-N concentrations exceeding maximum allowable concentrations of 11.3 ppm recommended by the World Health Organisation for potable drinking water which is accepted as a public health standard in New Zealand. Over half (56%) of the sites had concentrations that exceeded 3 ppm, indicating effects of human activities (commonly referred to as a human activity value). Very few trends in NO3(-)-N concentration that could be attributed to land use were identified, although market garden sites had higher concentrations of NO3(-)-N in underlying groundwater than drystock/sheep sites when the land use within 500 m radius of a sampling site was used to define the land use. There was also some evidence that within a district, NO3(-)-N concentrations in groundwater increased as the proportion of area used for dairy farming increased. Compared to pastoral land, market gardens had lower total C and N, potentially mineralisable N and denitrifying enzyme assay. However, none of these soil properties were directly related to groundwater NO3(-)-N concentrations. Instead, the DRASTIC index (which ranks sites according to their risk of solute leaching) gave the best correlation with groundwater NO3(-)-N concentrations. The permeability of the vadose zone was the most important parameter. The three approaches used were all considered unsuitable for assessing nitrate concentrations of groundwater, although a best-fit combination of parameters measured was able to account for nearly half the variance in groundwater NO3(-)-N concentrations. We suggest that non-point source groundwater NO3(-)-N contamination in the region reflects the intensive agricultural practices, and that localised, site-specific, factors may affect NO3(-)-N concentrations in shallow groundwaters as much as the general land use in the surrounding area.

Agriculture↗
PubMed2003

[Concentrations of selected bioelements and toxic metals and their influence on health status of children and youth residing in Szczecin].

This study was performed in 174 children (59 boys and 115 girls) residing in Szczecin. The objective was to measure the concentrations of heavy metals--lead and cadmium--and some bioelements--magnesium, zinc, copper, calcium, and iron--and to establish relationships between concentrations of elements in serum, erythrocytes, and hair. Mean concentrations of lead in serum and erythrocytes were 0.003 micromol/L (0.07 microg/dL) and 0.96 micromol/L (2.0 microg/dL), respectively (Table 1). Mean concentrations of cadmium in serum and erythrocytes were 0.006 micromol/L (0.07 microg/dL) and 0.02 micromol/L (0.21 microg/dL), respectively (Table 4). In both cases, the maximum allowable concentrations were not exceeded. In hair, the concentrations exceeded the maximum allowable concentration, reaching 0.006 micromol/g dry mass (1.2 microg/g d.m.) for lead and 0.0008 micromol/g d.m. (0.1 microg/g d.m.) for cadmium (Table 3). A positive correlation was found between the concentration of lead in erythrocytes and hair (r = 0.37, p < 0.000001). Concentrations of magnesium in serum and erythrocytes were below the normal range, but were within norm in hair. Mean concentrations of total magnesium in serum, erythrocytes, and hair were 0.69 mmol/L (1.7 mg/dL), 1.6 mmol/L (3.9 mg/dL), and 0.9 micromol/g d.m. (21.5 microg/g d.m.(, respectively (Table 4). 35 children with hypomagnesemia and elevated concentrations of lead and cadmium were placed on magnesium supplementation with Laktomag B6 preparation. This led to significant reduction in the concentrations of lead and cadmium in erythrocytes and hair. Mean concentration of lead diminished from 0.28 micromol/L (5.8 microg/dL) to 0.17 micromol/L (3.6 microg/dL) (p < 0.03) in erythrocytes and from 0.014 micromol/g d.m. (2.9 microg/g d.m.) to 0.007 micromol/g d.m. (1.5 microg/g d.m.) (p < 0.001) (table 5). Mean concentration of cadmium diminished from 0.02 micromol/L (0.23 microg/dL) to 0.015 micromol/L (0.17 microg/dL) in erythrocytes (p < 0.002) and from 0.009 micromol/g d.m. (0.1 microg/g d.m.) to 0.0009 micromol/g d.m. (0.01 microg/g d.m.) in hair (p < 0.02) (Table 6). Magnesium supplementation caused a significant increase in ionized magnesium in serum and and insignificant increase in erythrocytes and hair. No correlations were found in the examined children between hypomagnesemia, elevated levels of lead and cadmium in blood and hair, and health status.

Adolescent↗
PubMed1997

Concentration of cadmium in rice and urinary indicators of renal dysfunction.

OBJECTIVES: (1) To examine the relation between concentrations of cadmium (Cd) in rice and urinary concentrations of indicators of renal dysfunction and the prevalence of abnormalities in urine in areas polluted by Cd. (2) To establish the maximum allowable concentration of Cd in rice from these findings. METHODS: The target population consisted of 1703 inhabitants (832 men and 871 women) aged over 50 years who consumed home grown rice and had lived in the same hamlet in areas polluted by Cd in the Kakehashi River basin in Ishikawa Prefecture, Japan for at least 30 years. The correlation coefficients between concentrations of Cd in rice and several urinary substances, the prevalence of abnormalities in urine and sex in hamlets polluted by Cd were calculated. Finally, regression analysis was performed for significant indicators to calculate the maximum allowable concentration of Cd in rice based on values in a control group. CONCLUSIONS: Significant correlations between concentration of Cd in rice and concentrations of urinary beta 2-microglobulin, metallothionein, glucose, and aminonitrogen were established. Similarly, there were significant correlations between concentration of Cd in rice and the prevalence of beta 2-microglobulinuria, metallothioneinuria, glucosuria, proteinuria, proteinuria with glucosuria, and aminonitrogenuria. The highest maximum allowable concentration of Cd in rice calculated for these indicators was 0.34 ppm/l and 0.29 ppm/g creatinine. Both values are lower than 0.4 ppm, the tentative limit prescribed by the Japanese government.

Aged↗
PubMed2001

[Occupational exposure to gases emitted in mild and stainless steel welding].

The objective of this work was to select optimal methods for determination of toxic gases (NOx, NO2, CO, CO2, O3) and to evaluate occupational exposure of welders to those gases. The survey covered workers employed in shipyards, and other metal product fabrication plants engaged in welding mild and stainless steel by different techniques (manual metal are, metal active gas, tungsten inert gas welding; gas, plasma, laser cutting and resistance welding). Personal and stationary air samples were collected to determine time weighted average (TWA) and short-term concentrations of gases. For determination of nitrogen oxides the following analytical techniques were employed: spectrophotometry with collection on liquid and solid sorbents and ion chromatography with collection on solid sorbents. All the gases were determined also by automatic or direct reading methods: flow or diffusion detector tubes and photometric and electrochemical analyzers. The determined TWA concentrations were below respective Maximum Allowable Concentrations (MAC) but exposure limits for short term exposure were exceeded in some cases. The average NO2 i NOx ratio was 1:4. According to Polish regulations regarding the MAC value for nitrogen oxides the analytical method should enable determination of total NOx by either direct or indirect simultaneous determination of both NO and NO2. The applicability of the spectrophotometric method of analysis of atmospheric NOx to determination of low NOx concentrations at welders working posts has been confirmed.

Air Pollutants, Occupational↗
PubMed1998

Occupational effects on the health of workers and laboratory technicians in petrochemical plants.

A study was conducted over a 3-year period on the morbidity in petrochemical plants producing xylene, benzene, phenol and acetone, and in the related service laboratory. The incidence rate of system and target organ disorders due to the adverse effects of benzene, toluene, xylene, phenol, acetone, etc., was calculated. The exposure to chemical hazards (except benzene) of plant workers was not high--the concentrations were below the maximum allowable concentrations (MACs) and the duration of contact was not longer than 270 min per 8-h shift. The duration of exposure for laboratory technicians (all female) comprised an entire 8-h working shift, but concentrations of the chemical substances did not exceed MACs. The incidence rate of system and target organ disorders as a total of all production plants was 6% on average over the 3-year period, and for laboratory workers it was 10.3%. The average total incidence rate (comprising all diseases) was 42% in the production plants and comparatively greater in the laboratory--56% as an average for the period. Since laboratory technician posts are well mainly by women in Bulgaria, recommendations are to minimize contact with chemical hazards for women of child-bearing age, as was the case for benzene.

Chemical Industry↗
PubMedDate not supplied

[Estimating the hazard of toxic exposure of the population living in the area of the Orenburg gas-chemical complex to specific pollutants].

Health anomalies in children are induced by environmental contamination with pollutants specific for this region due to the long-term running of the Orenburg gas-chemical complex. On assessing the health hazard of exposure to non-carcinogenic chemicals, the authors used such variable as the hazard coefficient. Estimations indicated that the hazard coefficient of non-carcinogenic effects was greater than the allowable level with reference to hydrogen sulfide in all areas under study, as shown by the data of stationary posts. According to the data of route studies, the hazard coefficient exceeded 1 with reference to hydrogen sulfide and nitrogen dioxide. Thus, upon exposure to specific air pollutants, such hydrogen sulfide and nitrogen dioxide, even at the concentrations below the maximum allowable concentration there is an increased hazard of their toxic effect on the population.

Adult↗