Abstract  Abstract The aim of this work was to assess the relationships between lead (Pb) and uranium (U) exposure, lipid peroxidation and some enzyme activities in a mollusc (Cohicula sp.), an earthworm (Eisenia fetida) and a fish (Brachydanio redo). A comparative shrdy was perfotmed both in vibo and in vivo on whole organism postmitochondrial fractions and four potential biomarken were analyted: a marker of neurotoxicity (acetylcholinesterase activity, AChE, EC 3.1.1.7), a marker of oxidative sbss (malondialdehyde (MDA) level), and two markers of hydroperoxide detoxication: catalase (EC 1.11.1.6) and glutathione pemxidase (GPx, EC 1.11.1.9) activities. Our results have shown that the MDA contents were not signilicantty changed by exposures to lead either in vitro or in vivo. During uranium exposure, the MDA content was increased in vitro (particularly in fish samples) whereas this metal failed to sthnulate Spid peroxidation in vivo. With some exceptions, in vitro and in vivo exposures to lead and uranium showed that the AChE, catalase and GPx acbirites were decreased in the three species. These exceptions indicated that different mechanisms occurred in the different species. In conclusion, it was shown that S9 fractions of whole organisms could be useful for environmental contamination biomonitoring. Moreover, it was shown that AChE activities wen modulated by metals in viva and cannot be considered as specific bomarken of organophosphorus or carbaw pedcide exposure. Acetylcholinesterase and catalase activieies cwld be used to survey lead and uranium contamination.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. Potamogeton foliosus (an aquatic plant) and filamentous algae from a settling basin with contaminated sediment became enriched with polychlorinated biphenyls (PCBs), Co, Cd, Cu, Hg, Ni, Mn, U, and Zn. During the growing season, large amounts of the contaminated Potamogeton foliosus and algae were exported downstream from this basin to East Fork Poplar Creek (EFPC). We used drift nets to estimate the loading rates of the plants to EFPC, analyzed samples of the plants for metals, and conducted a series of experiments with snails (Elimia clavaeformis), amphipods (Gammarus sp.), and a microcrustacean (Ceriodaphnia dubia) to evaluate the possible effects of inputs of the vegetation to EFPC biota. Little of the vegetation that entered the stream was transported intact as far as 1.4 km. During the growing season, inputs of organic carbon to this 1.4-km segment of stream due to the deposition of the plants were at least 2.4 times greater than autochthonous production. Thus the v

Abstract  BIOSIS COPYRIGHT: BIOL ABS. The rate and magnitude of contaminant release from mill tailings to groundwater are known to depend on the form and mineralogy of the host grains. Using samples from three uranium mill sites in the western United States, we identified four types of alpha-emitting host grains-those containing barium-strontium sulfates, authigenic siliceous material, uranium minerals, and iron-titanium-vanadium oxides. These four grain types constitute a classification scheme for the tailings. Each milling process (acid or alkaline) produces distinct types of grains. In acid-milled tailings, such as those at Slick Rock, Colorado, the dominant source of alpha emissions is from barium-strontium sulfate. The barium-to-strontium ratio covers the entire solid-solution range between barite and celestite. In alkaline-milled tailings, alpha emissions come predominantly from siliceous composite grains, wwhich are interpreted as grains from the mill feed that have been altered during milling. In the

Abstract  Studies of tubular injury and necrosis caused by heavy metals have indicated involvement by various parts of the proximal tubule. This paper describes the patterns of injury seen after administration of mercuric chloride, uranyl nitrate, and cisplatin to animal models. Studies describing a possible role of the mesangium of the renal corpuscle in proximal tubular injury are included.

Abstract  It is well established that certain metals are toxic to embryonic and fetal tissues and can induce teratogenicity in mammals. The main objective of this paper has been to summarize the toxic effects that excesses of certain metals may cause on mammalian development. The reviewed elements have been divided into four groups: (a) metals of greatest toxicological significance (arsenic, cadmium, lead, mercury, and uranium) that are wide-spread in the human environment, (b) essential trace metals (chromium, cobalt, manganese, selenium, and zinc), (c) other metals with evident biological interest (nickel and vanadium), and (d) metals of pharmacological interest (aluminum, gallium, and lithium). A summary of the therapeutic use of chelating agents in the prevention of metal-induced developmental toxicity has also been included. meso-2,3-Dimercaptosuccinic acid (DMSA) and sodium 2,3-dimercaptopropane-1-sulfonate (DMPS) have been reported to be effective in alleviating arsenic- and mercury-induced teratogenesis, whereas sodium 4,5-dihydroxybenzene-1,3-disulfonate (Tiron) would protect against vanadium- and uranium-induced developmental toxicity.

Abstract  Ten individuals developed an asthma-like illness after a single exposure to high levels of an irritating vapor, fume, or smoke. In most instances, the high level exposure was the result of an accident occurring in the workplace or a situation where there was poor ventilation and limited air exchange in the area. In all cases, symptoms developed within a few hours and often minutes after exposure. We have designated the illness as reactive airway dysfunction syndrome (RADS) because a consistent physiologic accompaniment was airways hyperreactivity. When tested, all subjects showed positive methacholine challenge tests. No documented preexisting respiratory illness was identified nor did subjects relate past respiratory complaints. In two subjects, atopy was documented, but in all others, no evidence of allergy was identified. In the majority of the cases, there was persistence of respiratory symptoms and continuation of airways hyperreactivity for more than one year and often several years after the incident. The incriminated etiologic agent varied, but all shared a common characteristic of being irritant in nature. In two cases, bronchial biopsy specimens were available, and an airways inflammatory response was noted. This investigation suggests acute high level, uncontrolled irritant exposures may cause an asthma-like syndrome in some individuals which is different from typical occupational asthma. It can lead to long-term sequelae and chronic airways disease. Nonimmunologic mechanisms seem operative in the pathogenesis of this syndrome.

Abstract  The complexation of uranium(VI) to variant functional groups of the highly phosphorylated protein phosvitin in aqueous solution was investigated by attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy. For the verification of the affinity of the actinyl ions to carboxyl and phosphate groups of the amino acid side chains, samples with different phosphate to uranium(VI) (P/U) ratios were investigated under denaturing conditions as well as in aqueous medium. From a comparative study with other heavy metal ions, i.e. Ba(2+) and Pb(2+), a strong coordination of U(VI) to carboxyl and phosphoryl groups can be derived. Furthermore, with increasing P/U ratios, a preferential binding of U(VI) to phosphoryl groups is indicated by the spectra of the batch samples. These findings are confirmed by spectra of aqueous U(VI)-phosvitin complexes reflecting an explicit coordination of the uranyl ions to phosphate groups at a high P/U ratio. Our study provides a deeper insight into the molecular interactions between actinyl ions and protein, and can be conferred to other basic biomolecules such as polysaccharides and nucleic acids.

Abstract  The sale of botanical dietary supplements in the United States is on the rise. However, limited studies have been conducted on the safety of these supplements. There are reports on the presence of undesired metals in some of the botanical dietary supplements. In this study, echinacea, garlic, ginkgo, ginseng, grape seed extract, kava kava, saw palmetto, and St. John's wort supplements manufactured by Nature's Way, Meijer, GNC, Nutrilite, Solaray, Sundown and Natrol, have been analyzed for lead, mercury, cadmium, arsenic, uranium, chromium, vanadium, copper, zinc, molybdenum, palladium, tin, antimony, thallium, and tungsten using inductively coupled plasma mass spectrometry. All samples were devoid of mercury contamination. Results indicated that the botanical supplements analyzed did not contain unacceptable concentrations of these metals. These supplements were also evaluated for microbial contamination, and most samples analyzed showed the presence of bacteria or fungi or both. Microbes were not counted nor were microbial counts determined in these samples.

Abstract  This text presents natural and synthetic environmental hazards and the health risks that they pose. It is intended for use by students of environmental sciences and toxicology. The author provides an introduction to pharmacology, toxicology, and risk assessment. Issues covered are water pollution, air-borne hazards, halogenated hydrocarbons, toxicity of metals, organic solvents, food toxicants, pesticides, toxins from unicellular organisms, animal and plant poisons, and radiation hazards. Each chapter contains examples, case studies, review questions with answers, and suggestions for further reading.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. The ultimate aim of ecotoxicological studies is to predict how natural populations respond to contaminant exposure. Thus, it is crucial to understand how genetic and environmental factors in the field modify responses measured in the laboratory. In the present study the authors determine the genetic and environmental components of variability in acute responses among four Daphnia magna clones exposed to both essential (Zn and Cu) and non-essential (Cd and U) metals in waters with varying water hardness. The authors postulate that genotype acute responses to physiologically non-essential metals may be more variable than responses to essential metals and that this may be explained by hypothesizing that acute responses to non-essential substances are subject to intermittent selection (since the substances may not always be present in biologically significant amounts), whereas responses to essential substances are subject to continuous directional selection (since essential

Abstract  BIOSIS COPYRIGHT: BIOL ABS. The concentrations of 44 chemical elements in different compartments of Dipterocarpaceae, a major canopy component tree, are investigated. The fingerprints revealed a uniform tendency of all 18 species investigated to exhibit low concentrations of elements compared to the 'reference plant' proposed by Markert (Instrumental Element and Multi-Element Analysis of Plant Samples. Methods and Applications. Chicester: John Wiley, 1996:296 p.). Practically no accumulations of elements were found. The different compartments showed considerably different element concentrations with most elements showing the highest mean concentration in the leaves or twigs and the lowest mean concentration in the trunks. A comparison of mature trees and saplings of Dryobalanops lanceolata revealed higher concentrations for most elements in the saplings. From our knowledge this study can be considered as a first approach to access a tropical ecosystem on the basis of such a large scale of chemical

Abstract  The effect of arsenic (7440382) on the toxicity of selenium (7782492) was investigated in rats. Rats were fed diets containing 11 parts per million (ppm) selenium in wheat. Animals were divided into groups given drinking water containing 5ppm tungsten (7440337), fluorine (7782414), molybdenum (7439987), arsenic, chromium (7440473), vanadium (7440622), cadmium (7440439), zinc (7440666), cobalt (7440484), uranium (7440611), or nickel (7440020). Additional groups received selenium diet with no elements in drinking water or distilled water and a selenium free diet. Differences in weight and food consumption were noted. Survivors were killed on day 130 and examined for liver damage. By day 60, there was an increase in mortality rate in rats given fluorine, molybdenum, chromium, cadmium, vanadium, zinc, cobalt, and uranium. All rats in the tungsten and arsenic groups were living and normal in appearance on day 60. Examination of livers of rats fed selenium alone, selenium with nickel, and of controls were normal. Liver concentrations of selenium in the group given arsenic were much lower than in other groups, except for the one surviving rat given vanadium. None of the rats given tungsten had any appreciable liver damage. Rats were given selenium and 2.5ppm arsenic or tungsten in water for 75 days and autopsied. Arsenic partially prevented liver damage in rats fed selenium; they consumed more food and grew more rapidly than rats not given arsenic. Tungsten had no effect in preventing the symptoms of selenium poisoning, but rats given tungsten with selenium lived longer than those given selenium alone.

Abstract  The carcinogenicity of inorganic arsenic in humans, particularly in the lung and skin, has been reasonably well established through epidemiological investigations. However, there is no substantial experimental evidence for carcinogenicity in animals to suort the human studies. Studies of metabolism and disposition of inorganic arsenic in various animal species are particularly relevant to determining the factors that might account for the lack of an animal model. Numerous studies of this type have been reported, but there do not appear to be clear qualitative or quantitative differences in the overall fate and disposition of inorganic arsenic in most animals versus humans, although little is known at the cellular and subcellular level. Sulphur chemistry, especially thiol status, is emerging as an important regulating factor in the overall fate and distribution of inorganic arsenic in the body, playing a role in the initial reduction of arsenate to arsenite and subsequent methylation, and possibly in determining tissue affinity and distribution properties. The metabolism of inorganic arsenic can be viewed as a redox cycle in which thiol compounds such as glutathione (GSH) possibly function as reducing agents and methyl donors as oxidising agents. One explanation for the possible sensitivity of certain malnourished human populations to the carcinogenic effects of inorganic arsenic may be related to the reduced availability of nonprotein sulphhydryl compounds such as GSH needed to drive the redox cycle and facilitate arsenic detoxification. Future carcinogenicity studies of inorganic arsenic in animals could be designed to address directly this aspect of the problem.

Abstract  HEEP COPYRIGHT: BIOL ABS. The excess of lung cancer observed in the yr 1948-1975 in a large group of U miners was related to different conditions of long-term exposure to Rn daughter products. The dose-effect relationship differed with different time distribution of exposure; at higher cumulated exposure the lung cancer incidence per unit of exposure decreased with the increase of exposure rate. This decrease concerned mainly the incidence of small cell undifferentiated type of cancer.

Abstract  The influence of radon and radon daughters on development of respiratory cancer is reviewed. Epidemiological studies thus far indicate that excess lung cancer mortality is connected with miners having cumulative radon (10043922) daughter exposures somewhat below 100 working level month (WLM). A WLM is defined as a 170 hour working month exposure to alpha radiation from radon daughters equal to 1.3 x 10(5) megaelectron volts emitted in 1 liter of air. Special groups which seem to be at particular risk from radon daughters include smokers or individuals with pulmonary disease. Their increased risk results from stimulation of cell division in the bronchial tree. An additive rather than a multiplicative model has been gaining support to illustrate the connection between smoking and radon daughter induced lung cancer. It is recommended that a national radon survey be conducted seeking information on the radon concentration in air and water in homes in the United States. Such a survey will locate areas of high geologic radon exposure that would not be detected by special purpose surveys. International pooling of data is suggested to improve epidemiologic information already gathered. Epidemiologic studies of miners which are currently in progress should be continued and additional populations should be placed under study if the exposure pattern justifies such study. The conducting of experimental animal studies is also recommended so that modifications can be made in human exposures and thereby lessen the likelihood of lung cancer developing in exposed populations. The development of a personal dosimeter for occupational radon exposure is encouraged.

Abstract  HEEP COPYRIGHT: BIOL ABS. The 2,2'-diaminodiethylamine (DEN) functional group can be expected to have ideal properties for the chelation of transition metals and their collection from aqueous solutions, independent of the alkali and alkaline earth ions concentration. Introducing DEN into cellulose filters allowed preconcentration of trace cations by a simple filtration step, and the DEN-filter constituted a suitable target for X-ray fluorescence (XRF) analysis. The linearity between the XRF-response on the loaded DEN-filter and the trace cation concentration in the solution was excellent, up to a total filter capacity ofses. Accuracy and precision weree proposed procedure was illustrated on a comparative basis by XRF-analysis of drinking water and surface water after preconcentration by DEN-filtration and by alternative procedures.

Abstract  HEEP COPYRIGHT: BIOL ABS. The problem of health effects of Rn emissions from U mill tailings was reviewed. The history of estimates of these effects and how they were refined by further research was traced and a current best estimate given. The theory and practice of mitigating the effects by covering tailings with soil were described; and the present situation as regulated by the new 10 CFR 40, Appendix A was evaluated.

Abstract  The performance of a passive electret dosimeter in measuring radon (10043922) progeny in the laboratory and in a uranium (7440611) mine was evaluated. The dosimeter head was modified to suit the requirements for aerosol collection by electrostatic diffusion. The 6 millimeter gap between the collimators and the collecting surface in the dosimeter was preserved by replacing the filter in the dosimeter by the electret. The dosimeter was exposed inside a wind tunnel in a radon chamber at about 4 working stages for 2 hours. The electret dosimeter design was then adopted for a 1 week test in a uranium mine. The uranium mine used for testing was diesel operated and contained aerosols at concentrations in the range of 200,000 to 300,000 per cubic meter. Miners wore the passive dosimeter in addition to the reference dosimeter in the mines while working for 3 or 4 day periods. Passive dosimeter data was somewhat lower than that obtained from the reference dosimeters. The passive dosimeters were rugged enough for use in the mine atmosphere and no part of the electret dosimeters suffered any physical damage in the mine tests. The authors conclude that the high aerosol concentrations may have contributed to the efficiency of the dosimeter by a factor of 3 to 4 below what would have been expected based on preliminary laboratory work at lower aerosol concentrations.

Abstract  Uranium tailings piles are generally rehabilitated by covering them with a number of layers of earthen materials. This paper derives exact equations for the Rn concentration profile and flux attenuation through any number of covering layers. The equations take account of the distribution of Rn between interstitial air and water. Numerical examples are given to show that approximate methods give rise to significant errors in some circumstances. The flux attenuation factor depends not only on the diffusion coefficient, porosity, moisture content and thickness of each layer but also upon the order of placement. To achieve maximum flux attenuation, the least permeable material should be uppermost.

Abstract  In the case of U mines containing Th, the total alpha energy will contain contributions from both 222Rn progeny and 220Rn progeny. A simple routine grab sampling monitoring scheme is therefore needed for separate measurement of the working levels of 222Rn and 220Rn progeny. The scheme presented here is based on a short delay period after sampling (2 min) for 222Rn progeny and a long delay period (340 min) before counting 220Rn progeny. An advantage of this scheme is that no corrections need to be made to the 222Rn progeny working level for the presence of 220Rn progeny. Such corrections must be made in the commonly used Kusnetz scheme.

Abstract  A method involving the use of paper ionophoresis is described for the study of equilibria in mixed - ligand complex systems in solution. The technique is based on the movement of a spot of metal ion under an electric field with the complexants added to the background electrolyte at pH 8.5. The stability constants of the complexes Pb(II) - nitrilotriacetate - cysteine and UO2(II) - nitrilotriacetate - cysteine are found to be 5.35 +/- 0.02 and 6.27 +/- 0.07 (logarithm of stability constant values) at ionic strength 0.1 M and a temperature of 35 degrees C.

Abstract  Stability constants of binary [Pb(II) - methionine], [UO2II) - methionine] and mixed [Pb(II) - methionine - penicillamine], [UO2(II) - methionine - penicillamine] complexes have been determined by Paper Electrophoretic Technique at ionic strength 0.1 M. The stability constants of [Pb(II) - methionine - penicillamine] and [UO2(II) - methionine - penicillamine] mixed complexes were found to be 6.60 +/- 0.09 and 9.05 +/- 0.13 (logarithm of stability constant values), respectively at a temperature of 35 degrees C.

Abstract  A method has been developed for determination of thorium isotopes in water and soil samples by alpha-spectrometry. After fusion with Na(2)CO(3) and Na(2)O(2) at 600 degrees C, soil samples were leached with HNO(3) and HCl. Thorium in water sample or in soil leaching solution was coprecipitated together with iron (III) as hydroxides and/or carbonates at pH 9 with ammonia solution, separated from uranium and other alpha-emitters by a Microthene-TOPO (tri-octyl-phosphine oxide) chromatographic column, electrodeposited on a stainless steel disk, and measured by alpha-spectrometry. The method was checked with two certified reference materials supplied by the IAEA, and reliable results were obtained. The detection limits of the method for water (soil) samples are 0.44 microBq l(-1) (0.070 Bq kg(-1)) for (232)Th, 0.80 microBq l(-1) (0.13 Bq kg(-1)) for (230)Th and 1.0 microBq l(-1) (0.16 Bq kg(-1)) for (228)Th, respectively, if 100 l of water (0.50 g) for each sample are analysed. A variety of water or soil samples were analysed using this procedure and giving average thorium yields of 75.5+/-14.2% for water and 93.4+/-4.5% for soil. The obtained concentrations of thorium isotopes in water samples are in the range of 0.0007-0.0326 mBq l(-1) for (232)Th, <or= 0.0008-0.0258 mBq l(-1) for (230)Th and 0.0014-1.32 mBq l(-1) for (228)Th. The (230)Th/(232)Th and (228)Th/(232)Th ratios are in the range of <or= 0.57-3.9 and 1.06-717, respectively. The disequilibrium between (232)Th and (228)Th activity in water is observed and the fate of thorium isotopes in water was studied. The exposure impact due to intake of thorium in the analysed drinking water was evaluated, showing a negligible amount of dose contribution. The concentrations of (232)Th, (230)Th and (228)Th in the analysed soil samples are in the range of 30.2-48.6, 32.5-60.5 and 31.0-53.0 Bq kg(-1), respectively. The obtained mean ratio is 1.04+/-0.05 for (228)Th/(232)Th and 1.20+/-0.41 for (230)Th/(232)Th.