The effects of an intratracheal inoculation of graded doses of coal fly ash were investigated in the lungs of rats. Animals exposed to increasing concentrations of the dust did not significantly increase the wet and dry weight of lungs. Collagen contents of lungs, estimated as hydroxyproline, increased significantly with lapse in time and was dependent on the dust concentration used. The dust produced a marked macrophage response in the alveoli and a thickening of the interalveolar septa, due to cellular infiltration and proliferation of argyrophilic fibres. Irrespective of the amount of dust injected, foci of dust laden macrophages were present in the mediastinal lymph nodes at all time periods. In the bronchoalveolar lavage the number of cells increased very significantly with an increase in the amount of fly ash injected. Increase in the cellular constituents of the bronchoalveolar lavage was associated with a statistically significant increase in the lactate dehydrogenase enzyme activity and protein, contents. The data obtained suggest a dose‐related toxicity of fly ash on lungs.
This paper reviews the information available on lead pollution in Saudi Arabia. Comparison with some information from some countries is made. It was found that the atmospheric lead concentration in some cities in Saudi Arabia exceeds the European and American standards. The lead level in the blood of Saudi School children is reported. This is found to be within the international range. The Saudi plan for lead phasedown is stated. Alternatives for octane enhancement and the impact of lead phasedown on the Saudi environment are discussed. It is concluded that lead phasedown will significantly improve the environment's quality.
Molasses stillage 1s a pyproduct of the sugar cane Industry in Egypt. Candida utilis and Paecilomyces variotii were used separately and in a mixed culture for treatment of this still age and biomass production. A two‐steps aerobic batch process has been adopted. The distillery waste water was treated with C. utilis 1n the first step and with P.. variotii 1n the second step, which was carried out on the supernatant from the first step. The total reduction of the chemical oxygen was found to be 90%, using the mixed culture. On the other hand, the produced biomass was 22 gL‐1, using the mixed culture with a productivity of about 0.5 gL‐1h‐1. On using C. utilis, the biomass produced was 18 gL‐1 and the reduction of the COD of 45% was obtained. Meanwhile, the biomass produced was 5 gL‐1 and the reduction 1n COD of 70% was achieved, using J variotii. The chemical composition and amino content as well as the biological value of the produced biomass have been given. The amino acid profiles are very similar and comparable to FAO reference protein, but with a low content of methionin and cystin and a high content of leusin, lysin and thereonin.
The literature was reviewed for nitrate leaching under irrigation. The mass of nitrate leached is directly related to the percolation volume. Both water management and nitrogen management are important in controlling nitrate leaching. Applying only enough nitrogen fertilizer to meet yield goals, timing of nitrogen application and the use of slow release fertilizers are nitrogen management practices that will reduce nitrate leaching. There have been a number of nitrogen simulation models that have been developed, but there is a lack of field data to validate the models.
Studies indicated that duckweed absorbed mercury in water (e.g. lakes) strongly and that after three days it contained up to 2000 ppm of mercury by weight of duckweed. The uptake of mercury was little affected by acidity at pH 4.0 and pH 5.0. The presence of copper ion suppressed the mercury uptake significantly. The presence of 1.0 mM EDTA in solution also suppressed the mercury uptake significantly. Further 10 mg of humic acid in 400 mL solution suppressed the mercury uptake to some degree, probably by complexing the mercury.
Much attention has been given to groundwater contamination due to the release of hazardous constituents from treatment and disposal facilities. Since some of the constituents entered groundwater aquifers in much shorter times than had been calculated, regulatory agencies have become concerned that hazardous constituents may be escaping from units not currently regulated under hazardous waste management programs. One of the major concerns of regulators is that unlined earthen surface impoundments in industrial wastewater treatment trains may be leaking heavy metals such as chromium and other hazardous constituents into the groundwater. The Environmental Protection Agency is moving toward bringing such impoundments under the Resource Conservation and Recovery Act (RCRA) regulations. In addition, EPA is now proposing to list hexavalent chromium as a hazardous air pollutant due to its possible release from the mist of cooling towers, citing hexavalent chromium's potent carcinogenicity as the primary concern. While such a listing would primarily affect worker exposure, leakage of chromium from surface impoundments could enter groundwater sources and carry exposures far beyond industrial facilities. Industry has resisted the EPA's initiatives on the grounds that wastewater treatment units are not only efficient at removing metals but the accumulation of those metals in such systems do not pose a threat to the environment. Since the 1984 RCRA amendments require all surface impoundments containing hazardous wastes to be double‐lined, industry faces capital outlays estimated to be in the billions should all treatment systems be brought under RCRA regulations. This investigation deals with the sludges produced in a refinery wastewater treatment system utilizing unllned surface impoundments, and how those sludges are classified under current EPA testing protocols.
Algal assays were used to establish toxicity guidelines for natural waters. ‘Cu equivalent’ rather than the conventional EC 50 value was used as the toxicity unit. By correlating Cu dosages with % of control growth, Cu reference curves were constructed for our test species, Chlorella and Scenedesmus. These Cu curves, which compensated for species sensitivity differences, were then used to translate algal growth response to toxicity of the test waters. Expressed in Cu equivalent, our test waters displayed a toxicity range from 25 to 300 ug Cu.l‐1 . After further tests with Cu on organisms such as algae, Daphnia and rainbow trout, ‘sensitive’ water where delicate plankton species could not survive, was found at Cu eq. concentrations between 90 and 120 ug.l‐1.
The parent aromatic hydrocarbon, benzene, has been and still is used in industry on a large scale, although the use of it is generally avoided because of its adverse health effects. Hence, it is still possible to come across a number of benzene intoxication cases, due to its technically inappropriate way of use. It has been reported that the amount of absorption of benzene can be estimated by providing certain parameters, such as benzene in the inspired air and exhaled breath. The gaschromatographic methods used in the determination of these parameters seems to be accurate and highly specific, but needed time‐consuming pre‐arrengements and expesive apparatus not generally available in working places. Therefore, a practicable semi‐quantitative method was needed for screening tests to estimate the degree of exposure to benzene vapour. For this purpose, a laboratory method of making a colour indicator tube was developed for determination of benzene concentration in the exhaled breath. This tube is sensitive enough to determine benzene in breath down to 2 ppm. Benzene concentrations can be determined without being affected by up to 30 ppm of toluene. Xylene and cumene have no influence at all on the determination. The tube ca also be modified to determine atmospheric levels of benzene in the working environment.
Controlled field studies were conducted at material exposure sites at Research Triangle Park; NC, and Steubenville, OH, between April 25, 1987, and December 28, 1987. Automatic covering/spray systems located at each site were used to expose panels of galvanized steel and paints under the following conditions: (1) dry deposition only; (2) dry plus ambient wet deposition; and (3) dry deposition plus deionized water (Dl). Ambient and Dl‐runoff samples were collected on an event basis and underwent detailed chemical analyses. The results from the analyses of the Dl‐runoff samples from galvanized steel and oil‐based paint panels from each site are presented in this paper. The runoff results show that the dry deposition of acid gases at the sites increased the dissolution rate of galvanized steel corrosion products. At the Ohio site, gases and particulates leading to the formation of SO4= in the Dl‐runoff were the major contributing species to the dissolution rate. At the North Carolina site, this preliminary analysis suggests that in addition to SO4 =, precursors to runoff NO3 ‐ and HCOO‐ may contribute to the Zn dissolution rate. Although the average SO2 level in Steubenville was 10 times the North Carolina value, the Ohio to North Carolina Zn dissolution rate was only 1.9. This result, in conjunction with the presence of large amounts of dry‐deposited Ca in the Ohio runoff samples, suggests that the neutralization of acid gases by dry‐deposited basic particulates may have been important at the Ohio site. At the North Carolina site, low levels of anions were found in the paint runoff with H+ as the most abundant cation, a result consistent with the anticipated lack of reactivity toward acid gases due to the absence of alkaline‐paint components. The presence of large runoff concentrations of Ca and SO4 = at the Ohio site can be explained by increased reactivity of the surface due to dry‐deposited basic particles and/or dry deposition of CaSO4. Key words: atmospheric weatheringcorrosiondry depositiongalvanized steeloil‐based paintacid depositionneutralization.
This paper reports the behaviour of an anaerobic digester fed with pure, easily biodegradable substances (glucose and sucrose); for this a kinetic model was used based on the kinetic equation of growth in microorganisms defined by Contois. The model predicts with great exactitude the yields of the digester. Similarly a heavy dependency is observed on the maximum growth rate of the microorganisms of the type of substrate and the concentration of the influent.
12 species of Saprolegniaceae were isolated from three stations in Tigris river near Al‐Rashidiya, north east of Baghdad, Iraq, from November 1987 to February 1988. These are Achlya prolifera, A.aff.caroliniana, A.polyandra , A.americana, A.racemosa , A.treleaseana, A.debaryana, Saprolegnia ferax, S.uliginosa, S.terreatris, Dichtyuchua magnusii, and Calyptralegnia ripariensis. Out of 152 isolates 63 reached sexual maturity. Their occurrence have been studied, A.polyandra was the predominant species. It was the first record of S.uliginosa in Iraq.
The use of dual media filtration for treating Tigris River raw water is considered a new technique in Iraq. More than forty test runs employing different dual media filter configurations were conducted. A pilot plant designed to operate similarly to the full scale water treatment plant was used for this purpose. The results were statistically analyzed and a mathematical equation describing the relationship between involved variables was developed. The relative strength of each independent variable upon the effluent quality was also revealed.
The concentration of copper, iron, chromium and nickel in fish and shellfish of Geras gulf, Lesvos island, Greece are determined. Method used is that of Atomic Absorption Spectrometry. Correlation of metal concentration to species and season of the year is tried. Data are compared to the dally allowable values for human beings.
A systematic methodology for mathematically simulating photosynthetically driven DO variations in the mid‐Passaic River system is presented and discussed. A steady‐state model for BOD‐DO dynamics, calibrated and verified to data from two stream surveys conducted during the Summer and Fall of 1983, is first presented. Diurnal DO fluctuations due to algal photosynthetic activity are then simulated by Fourier series. The resultant models display good correlation to the data.
Surface and ground‐water quality were monitored in the Appoquinimink Watershed as part of the Appoquinimink Rural Clean Water Project (RCW)). Surface water was monitored for seven years and ground water was monitored for three years. As part of the RCWP plan, conservation tillage, fertilizer management and pesticide management were the most widely used best management practices. Best management practices decreased total phosphorus and total suspended solids concentrations in surface water. The unfiltered ortho phosphorus as a percentage of total phosphorus increased. Nitrogen concentrations did not change over the seven year monitoring period. The BOD concentrations increased because of increased residues left on the surface from conservation tillage. Atrazine was detected in the shallow ground water at concentrations ranging from 1 to 45 μg/L. Aldicarb was only detected in one monitoring well. Nitrate concentrations were above 10 mg/L in some areas of the watershed.
Blood samples from 19 healthy, mid‐income Floridians (5 females, 14 males) were collected and analyzed for copper, zinc, and selenium using atomic absorption spectroscopy. The mean (± 1 S.D.) values were copper 1.00 ± 0.29 ppm; zinc, 0.86 ± 0.19 ppm; and selenium, 132 ± 29 ppb. The mean selenium level for the females (n = 5) was 125 ± 37 ppb and 132 ± 31 ppb for males (n = 14). No significant difference was observed for the two groups. No correlation was observed between copper and zinc. The correlations between zinc and selenium appeared to fall into two groupings, and the correlation between copper and selenium appeared to be slightly negative. These are among the relatively few data that have been collected for selenium levels in Floridians, and implications are discussed.
Blood samples from 200 Saudi Arabian school boys, aged 6–8 years, were analyzed for their Pb concentrations by graphite furnace atomic absorption spectrometry, Mean Blood‐Pb concentration was found to be 6.9 (±3.4) ug/dl. The blood samples were also examined for some hematological parameters : total counts of erythrocytes and leucocytes, hematocrit, mean corpuscular volume, hemoglobin, mean corpuscular hemoglobin concentration, and basophilic stippling, using a Coulter Counter. All values obtained were within the ‘normal ranges’. However, the hematological effects of sub‐toxic levels of Pb in blood were assessed by considering the seven cases whose Blood‐Pb values were between 15 ‐ 25 ug/dl. The data indicate that sub‐toxic levels of Pb in blood may be related to early stages of microcytic anemia.
Low Temperature Carbonization Wastes contain high concentrations of various phenols, organic bases, ammonia, cyanide, thiocyanate and several other constituents of environmental concern. Fresh waste water is colourless to straw‐yellow in colour but changes to red or brownish red due to oxidative coupling of phenols resulting in quinone structures with C‐O‐C linkages.
Abstract A mathematical model of compressive thickening is developed which is based on Kos’ model yet can be calibrated from measurements of concentration, concentration gradient, and bulk underflow velocity in continuous thickening experiments. The need for sensitivity and difficult measurements such as interparticle pressure or volumetric solids concentration is eliminated. Numerical programs to simulate the model are described. The model was calibrated and tested using steady state continuous thickening experiments. Unsteady state continuous thickening was studied by use of computer simulation of the model. Programs are described for nonlinear regression of the models to continuous thickening column data, and for steady state and unsteady state simulation.
