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PubMed2006

Selecting a battery of bioassays for ecotoxicological characterization of wastes.

This study was conducted in France within the context of waste classification (Hazardous Waste Council Directive 91/689/EEC), and focused on "ecotoxic" property (H14). In 1998, an experimental test strategy was developed to assess ecotoxicological properties of wastes using a battery of six standardized bioassays. This combined direct and indirect approaches integrating two solid-phase tests: emergence and growth inhibition of Lactuca sativa (14 days), mortality of Eisenia fetida (14 days) and four standardized tests performed on water extracts from wastes: growth inhibition of Pseudokirchneriella subcapitata (3 days), inhibition of mobility of Daphnia magna (48 h), inhibition of reproduction of Ceriodaphnia dubia (7 days), inhibition of light emission of Vibrio fischeri (30 min). This study aimed to set up preliminary conclusions on relevancy of this experimental test strategy, based on data obtained since 1998. Results were analyzed from the combined use of Hierarchical Cluster Analysis, Principal Component Analysis and Nonlinear Mapping. These multivariate analyses clearly showed that it was possible to reduce this number of tests without changing the typology of the wastes. A battery of bioassays including one solid phase test and two tests performed on water extracts (L. sativa, V. fischeri and C. dubia) was found as an optimal solution for characterizing the toxicity of the studied wastes. This optimal battery represents a good basis for determining the H14 property.

Aliivibrio fischeri↗
PubMed2005

Simultaneous and synergistic conversion of dyes and heavy metal ions in aqueous TiO2 suspensions under visible-light illumination.

This study reports synergistic effects in the simultaneous conversion of dyes and heavy metal ions in aqueous TiO2/dye/metal ion systems (ternary components) under visible light (lambda > 420 nm). TiO2/Cr(VI)/Acid Orange 7 (AO7), TiO2/Cr(VI)/Rhodamine B (RhB), TiO2/Ag+/AO7, and TiO2/Ag+/RhB were chosen as test systems. Although dyes can be degraded in TiO2 suspensions under visible light, their removal rates were markedly enhanced in the presence of metal ions. Similarly, the reduction rates of metal ions in visible-light-illuminated TiO2 suspensions were negligible, but they were highly accelerated with dyes present. In particular, the synergistic effect in the ternary system of TiO2/Cr(VI)/AO7 was outstanding. The presence of dissolved oxygen increased the photoreduction rate of Cr(VI) despite the fact that Cr(VI) and O2 are competing electron acceptors. This is ascribed to in-situ photogenerated H2O2 from O2, which acts as a reductant of Cr(VI). RhB and Ag+ ions could be also converted simultaneously under visible light both in the presence and absence of TiO2. The visible-light-induced reduction of Ag+ did not occur at all in TiO2/Ag+ system, but it was enabled in both TiO2/Ag+/ RhB and TiO2/Ag+/AO7 to generate Ag particles. On the other hand, the binary systems of Cr(VI)/AO7, Ag+/AO7, and Ag+/RhB show significant visible-light activities for the conversion of both dye and metal ion. In this case, metal ions and dyes seem to form complexes that induce intracomplex electron transfers upon visible-light absorption. The Cr(VI)/RhB system, however, exhibited insignificant visible-light reactivity.

Azo Compounds↗
PubMed2003

Assessment of health risks to skin and lung of elevated radon levels in abandoned mines.

Radon, together with its progeny, is present in high levels in some underground sites. Radon is known to increase the risk of lung cancer, while increased levels of radon decay products on the skin surface have been implicated in skin cancer induction and at sufficient levels might cause deterministic effects such as erythema. Although radon levels in working mines are controlled, radon in abandoned mines can reach very high levels, which would result in an occupant exceeding recommended annual exposure limits in less than 2 h in some mines. The relative importance of dose limits for the lung, skin cancer, and deterministic effects is discussed in the light of practical experience.

Air Pollutants, Radioactive↗
PubMed2007

Life history variation in the heavy metal tolerant plant Thlaspi caerulescens growing in a network of contaminated and noncontaminated sites in southern France: role of gene flow, selection and phenotypic plasticity.

* Here we explore life history differences in a set of neighbouring metallicolous and nonmetallicolous populations of the heavy metal tolerant plant Thlaspi caerulescens. * We contrasted data from field observations and from a common garden experiment, in which soil zinc (Zn) concentration and light availability were manipulated, and data on microsatellite molecular variation. * The two ecotypes showed few differences in life history in the field, but large differences in their response to Zn concentration in the common garden. Soil toxicity affected most characters in nonmetallicolous plants, while it had no effect on metallicolous plants. The two ecotypes responded similarly to light. Genetic differentiation for quantitative characters between ecotypes contrasted with the absence of differentiation for microsatellites. Conversely, populations of the same ecotype showed similar responses to Zn, despite their high differentiation for molecular markers. * We conclude that divergent selection related to soil toxicity has had a predominant role in shaping life history differences between ecotypes, gene flow weakly opposing local adaptation despite geographical proximity.

Adaptation, Physiological↗
PubMed2024

Advancing responsible genomic analyses of ancient mollusc shells.

The analysis of the DNA entrapped in ancient shells of molluscs has the potential to shed light on the evolution and ecology of this very diverse phylum. Ancient genomics could help reconstruct the responses of molluscs to past climate change, pollution, and human subsistence practices at unprecedented temporal resolutions. Applications are however still in their infancy, partly due to our limited knowledge of DNA preservation in calcium carbonate shells and the need for optimized methods for responsible genomic data generation. To improve ancient shell genomic analyses, we applied high-throughput DNA sequencing to 27 Mytilus mussel shells dated to ~111-6500 years Before Present, and investigated the impact, on DNA recovery, of shell imaging, DNA extraction protocols and shell sub-sampling strategies. First, we detected no quantitative or qualitative deleterious effect of micro-computed tomography for recording shell 3D morphological information prior to sub-sampling. Then, we showed that double-digestion and bleach treatment of shell powder prior to silica-based DNA extraction improves shell DNA recovery, also suggesting that DNA is protected in preservation niches within ancient shells. Finally, all layers that compose Mytilus shells, i.e., the nacreous (aragonite) and prismatic (calcite) carbonate layers, with or without the outer organic layer (periostracum) proved to be valuable DNA reservoirs, with aragonite appearing as the best substrate for genomic analyses. Our work contributes to the understanding of long-term molecular preservation in biominerals and we anticipate that resulting recommendations will be helpful for future efficient and responsible genomic analyses of ancient mollusc shells.

Animals↗
PubMed1984

Correlation of benzene metabolism and histological lesions in rainbow trout (Salmo gairdneri).

Rainbow trout metabolized benzene to phenol and catechol, and excreted them primarily as glucuronide conjugates. Treatment with benzene or toluene resulted in spleenomegaly that may be a more generalized solvent effect on the circulating RBCs. Anemia was observed only in the benzene-treated animals. This may be a result of decreased erythropoiesis in the head kidney or a direct effect of the principal metabolite (phenol) or its reactive intermediate. Both the spleen and liver metabolized benzene in vitro, while no metabolism was observed in the head kidney or trunk kidney. This fact, along with the observed "covalently" bound material in the liver, spleen, and kidney in vivo, can be interpreted as indicating that a reactive metabolite is formed outside the head kidney and is transported to the head kidney where it results in the observed hematopoietic damage. A similar hypothesis has been suggested for the observed protection by partial hepatectomy against bone marrow effects in mammalian species. The effects observed in trout are similar to those reported for higher mammalian species, but the metabolic profile is simpler, and studies in these animals may shed light on the mechanism of benzene toxicity. The techniques developed for monitoring benzene toxicity in trout can also be used for examining other environmental pollutants that may affect the hematopoietic system of fish.

Animals↗
PubMed1984

Recent advances in occupational cancer.

The contribution of occupational and environmental exposures to the etiology of cancer is a topic of considerable scientific and public interest. If an occupational environmental exposure is associated with cancer in man, then both the exposure and the disease are preventable by appropriate protection. In order to enhance the awareness and timeliness of new information concerning occupational cancer, the University of California, San Francisco, School of Medicine in conjunction with the Northern California Occupational Health Center and the National Institutes of Occupational Safety and Health, the American Cancer Society sponsored a two day meeting in San Francisco at the end of 1983. Five of the presentations are highlighted in this review. In addition, twenty special questions of clinical relevance concerning occupational and environmental cancers are reviewed with the consensus answers given.

Acquired Immunodeficiency Syndrome↗
PubMed2002

An in situ bioassay for estuarine environments using the microalga Phaeodactylum tricornutum.

This study aimed at evaluating the potential of an in situ algal bioassay for routine toxicity estimates of potentially contaminated estuarine environments using the microalga Phaeodactylum tricornutum immobilized in alginate beads. The influence of the initial cell density in the beads and of salinity on algal growth was first investigated. The potential of the proposed bioassay was evaluated by comparing laboratory with in situ results. A good growth performance of P. tricornutum was observed at all starting densities of beads. Although the growth rate of P. tricornutum was significantly affected by salinity, acceptability criteria currently adopted in algal assays were met, indicating the suitability of P. tricornutum as a test species for bioassays in estuaries. The large differences observed between the laboratory and in situ responses of P. tricornutum were most probably due to the temperature and light conditions less favorable for algal growth in the field and to the lack of representativeness of water samples compared to the field fluctuating conditions. These results showed the need for in situ assessments, especially in estuarine environments influenced by tides. To a lesser extent, the bioassay itself may also have been responsible for the laboratory and field differences. Further improvements in the bioassay chambers and procedures were also discussed.

Biological Assay↗
PubMed2004

[Photocatalytic degradation of ethylene over titania-based photocatalysts].

The photocatalytic degradation of ethylene over titania-based photocatalysts was studied under a non-circulating system using visible or near-UV light. The roles of the reaction temperature and the inlet concentration of ethylene and the influence of different light source were investigated. Then the efficiency of noble metals-doped photocatalyst was compared with that of the bare one. The experiment results indicated that when the inlet concentration was in range of 38-188 mg/m3 the photo-degradation efficiency of the bare photocatalyst dropped linearly and very slowly with the increase of inlet concentration of ethylene; the degradation efficiency increased as raising the reaction temperature; noble metals not only decreased the recombination of electron-hole pairs, but also increased the absorption for visible light, leading to the photocatalytic efficiency in several-tens times higher in visible light.

Air Pollutants↗
PubMed2005

Effects of temperature and soil components on emissions from pyrolysis of pyrene-contaminated soil.

Effects of temperature and soil on yields and identities of light gases (H2, CH4, C2H2, C2H4, C2H6, CO, and CO2) and polycyclic aromatic hydrocarbons (PAH) from thermal treatment of a pyrene-contaminated (5 wt%) soil in the absence of oxygen were determined for a U.S. EPA synthetic soil matrix prepared to proxy U.S. Superfund soils. Shallow piles (140-170 mg) of contaminated soil particles and as controls, neat (non-contaminated) soil (140-160 mg), neat pyrene (10-15 mg), neat sand (230 mg), and pyrene-contaminated sand (160 mg), were heated in a ceramic boat inside a 1.65 cm i.d. pyrex tube at temperatures from 500 to 1100 degrees C under an axial flow of helium. Volatile products spent 0.2-0.4s at temperature before cooling. Light gases, PAH and a dichloromethane extract of the residue in the ceramic boat, were analyzed by gas chromatography or high pressure liquid chromatography (HPLC). Over 99% pyrene removal was observed when heating for a few tens of seconds in all investigated cases, i.e., at 500, 650, 750, 1000, and 1100 degrees C for soil, and 750 and 1000 degrees C for sand. However, each of these experiments gave significant yields (0.2-16 wt% of the initial pyrene) of other PAH, e.g., cyclopenta[cd]pyrene (CPP), which mutates bacterial cells and human cells in vitro. Heating pyrene-polluted soil gave pyrene conversions and yields of acetylene, CPP, and other PAH exceeding those predicted from similar, but separate heating of neat soil and neat pyrene. Up to 750 degrees C, recovered pyrene, other PAH, and light gases accounted for all or most of the initial pyrene whereas at 1000 and 1100 degrees C conversion to soot was significant. A kinetic analysis disentangled effects of soil-pyrene interactions and vapor phase pyrolysis of pyrene. Increase of residence time was found to be the main reason for the enhanced conversion of pyrene in the case of the presence of a solid soil or sand matrix. Light gas species released due to the thermal treatment, such as acetylene and methane, lead the formation of other, pyrene-derived PAH, e.g., methylpyrenes, cyclopenta[cd]pyrene, and benzo[a]pyrene. Implications of these findings for the chemistry of soil thermal decontamination and for diagnosing potential defects in soil thermal cleaning, e.g., incomplete elimination of targeted pollutants and formation of adverse by-products, are discussed.

Environmental Monitoring↗
PubMed2001

Pleural mesothelioma associated with indoor pollution of asbestos.

This case report concerns a 46-year-old woman, dying from histologically confirmed diffuse malignant mesothelioma after asbestos exposure, which was only caused by indoor pollution from crocidolite-containing spray asbestos in building materials. There was no other known occupational or environmental asbestos exposure during her life. The lung tissue fibre analysis by light microscopy showed significantly increased concentrations of ferruginous bodies (3162 FB per gram of wet lung tissue). By use of scanning transmission electron microscopy, clearly increased concentrations of amphibole fibres (8.6 x 10(6) fibres longer than 1 microm and 0.6 x 10(6) fibres longer than > or =5 microm per gram dry tissue), mainly classified as crocidolite, were observed. The disease was attributed to indoor exposure to sprayed asbestos, which occurred during her work as a decorator in the studio of a warehouse.

Air Pollution, Indoor↗
PubMed2003

A review of classic Fenton's peroxidation as an advanced oxidation technique.

Hydrogen peroxide (H(2)O(2)) is a strong oxidant and its application in the treatment of various inorganic and organic pollutants is well established. Still H(2)O(2) alone is not effective for high concentrations of certain refractory contaminants because of low rates of reaction at reasonable H(2)O(2) concentrations. Improvements can be achieved by using transition metal salts (e.g. iron salts) or ozone and UV-light can activate H(2)O(2) to form hydroxyl radicals, which are strong oxidants. Oxidation processes utilising activation of H(2)O(2) by iron salts, classically referred to as Fenton's reagent is known to be very effective in the destruction of many hazardous organic pollutants in water. The first part of our paper presents a literature review of the various Fenton reagent reactions which constitute the overall kinetic scheme with all possible side reactions. It also summarises previous publications on the relationships between the dominant parameters (e.g. [H(2)O(2)], [Fe(2+)], . . .). The second part of our review discusses the possibility of improving sludge dewaterability using Fenton's reagent.

Hydrogen Peroxide↗
PubMed1990

The head dome: a simplified method for human exposures to inhaled air pollutants.

Acute controlled exposures of human subjects to air pollutants are customarily carried out with whole-body chambers, masks, or mouthpieces. The use of these methods may be limited by cost or technical considerations. To permit a study involving a highly unstable pollutant, artificial acid fog, administered to subjects during natural breathing, a head-only exposure chamber, called a head dome, was developed. It consists of a transparent cylinder with a neck seal which fits over the subject's head and rests lightly on his shoulders. The head dome does not constrain the upper airways or impede exercise on a bicycle ergometer. Ventilation can be monitored accurately and unobtrusively with a pneumotachograph at the exhaust port of the dome. A thermocouple may be used to monitor the onset and persistence of oronasal breathing. For short-term exposures to unstable or reactive pollutants lasting up to several hours, the head dome is an effective alternative to a whole-body chamber and probably superior to a face mask or mouthpiece.

Air Pollutants↗
PubMed1993

[Do soluble organic nitrogen compounds cause unusual algal blooms in seawater?].

Up to now the nature and importance of the macromolecular forms of organic nitrogen in the marine environment is poorly understood. There is no doubt on the capacity of phytoplankton to utilize low molecule weight dissolved organic nitrogen compounds competitively with bacteria. In marine ecosystems the members of the plankton community show a complex close coupling with biological substances. In spite of trace concentrations the high dynamics in uptake and release processes cause strong fluxes of these compounds. In the case of inorganic nutrient deprivation or reduced photosynthesis under light deficiency algal utilization of organic nitrogen becomes noteworthy. Even under high nitrate supply an algal development occurred which was mainly triggered by amino acid uptake as was demonstrated during field experiments in the German Bight. The consumption of amino acids is controlled by several uptake systems, which are specified for transportation of different groups of amino acids through the cell wall. Since the uptake systems can also differ among species, the amino acid composition of the environment could preferentially enhance the growth of some selected species in comparison with other components of natural phytoplankton assembles. In the scope of increasing water pollution and the resulting shift in nutrient distribution one may expect the development of phytoplankton species, which had not been supported so far. In estuaries and costal zones photosynthesis is effected by light absorbance from particulate material. This phenomenon additionally will sustain algae, which are able to compensate a photosynthesis deficit by heterotrophic uptake. Though interrelationships are not clear up to now, it becomes evident that increasing impact of dissolved organic substances cause strong changes in species composition of marine ecosystems.

Amines↗
PubMed2004

Particulate matter from tobacco versus diesel car exhaust: an educational perspective.

BACKGROUND: Air pollution is a common alibi used by adolescents taking up smoking and by smokers uncertain about quitting. However, environmental tobacco smoke (ETS) causes fine particulate matter (PM) indoor pollution exceeding outdoor limits, while new engines and fuels have reduced particulate emissions by cars. Data comparing PM emission from ETS and a recently released diesel car are presented. METHODS: A 60 m3 garage was chosen to assess PM emission from three smouldering cigarettes (lit sequentially for 30 minutes) and from a TDCi 2000cc, idling for 30 minutes. RESULTS: Particulate was measured with a portable analyser with readings every two minutes. Background PM10, PM2.5, and PM1 levels (mean (SD)) were 15 (1), 13 (0.7), and 7 (0.6) microg/m3 in the car experiment and 36 (2), 28 (1), and 14 (0.8) microg/m3 in the ETS experiment, respectively. Mean (SD) PM recorded in the first hour after starting the engine were 44 (9), 31 (5), and 13 (1) microg/m3, while mean PM in the first hour after lighting cigarettes were 343 (192), 319 (178), and 168 (92) microg/m3 for PM(10), PM2.5, and PM1, respectively (p < 0.001, background corrected). CONCLUSIONS: ETS is a major source of PM pollution, contributing to indoor PM concentrations up to 10-fold those emitted from an idling ecodiesel engine. Besides its educational usefulness, this knowledge should also be considered from an ecological perspective.

Air Pollutants↗