Abstract  We report the findings of a comparative analysis examining patterns of accumulation and partitioning of the heavy metals copper (Cu), lead (Pb) and zinc (Zn) in mangroves from available field-based studies to date, employing both species level analyses and a phylogenetic approach. Despite mangroves being a taxonomically diverse group, metal accumulation and partitioning for all metals examined were broadly similar across genera and families. Patterns of metal accumulation were also similar regardless of whether species were classified as salt secreting or non-secreting. Metals were accumulated in roots to concentrations similar to those of adjacent sediments with root bio-concentration factors (BCF; ratio of root metal to sediment metal concentration) of <= 1. Root BCFs were constant across the exposure range for all metals. Metal concentrations in leaves were half that of roots or lower. Essential metals (Cu and Zn; translocation factors (TF; ratio of leaf metal to root metal concentration) of 0.52 and 0.53, and leaf BCFs of 0.47 and 0.51, respectively) showed greater mobility than non-essential metals (Pb; TF of 0.31 and leaf BCF of 0.11). Leaf BCFs for the essential metals Cu and Zn decreased as environmental concentrations increased. The non-essential metal Pb was excluded from leaf tissue regardless of environmental concentrations. Thus mangroves as a group tend to operate as excluder species for non-essential metals and regulators of essential metals. For phytoremediation initiatives, mangrove ecosystems are perhaps best employed as phytostabilisers, potentially aiding in the retention of toxic metals and thereby reducing transport to adjacent estuarine and marine systems. (C) 2007 Elsevier Ltd. All rights reserved.

Abstract  Surface water samples were collected from 42 sampling sites throughout the upper Han River during the time period of 2005-2006. The concentrations of trace metals were determined using inductively coupled plasma-atomic emission spectrometry (ICP-AES) for the seasonal variability and preliminary risk assessment. The results demonstrated that concentrations of 11 heavy metals showed significant seasonality and most variables exhibited higher levels in the rainy season. Principal component analysis (PCA) and factor analysis (FA) revealed that variables governing water quality in one season may not be important in another season. Risk of metals on human health was then evaluated using Hazard Quotient (HQ) and carcinogenic risk, and indicated that As with HQ >1 and carcinogenic risk >10(-4), was the most important pollutant leading to non-carcinogenic and carcinogenic concerns, in particular for children. The first five largest elements to chronic risks were As, Pb, V, Se and Sb, in the dry season, while they were As, V, Co, Pb and Sb in the rainy season. This assessment would help establish pollutant loading reduction goal and the total maximum daily loads, and consequently contribute to preserve public health in the Han River basin and develop water conservation strategy for the interbasin water transfer project.

Abstract  This study was performed to clarify the toxicological profiles of trichloroethylene (TRCE) and tetrachloroethylene (TECE) when they are administered intraperitoneally in mice. The ED50 for loss of righting reflex were 2596 mg/kg in TRCE and 4209 mg/kg in TECE. TRCE and TECE impaired bridge test performance at 500 and 2000 mg/kg, respectively. An operant behavior performance was also inhibited by TRCE at 1000 mg/kg and by TECE at 2000 mg/kg. Both TRCE and TECE exhibited anticonflict effects in a Vogel-type task at 500 mg/kg. This effect was confirmed by the finding that TRCE exhibited anticonflict action in a Geller-type paradigm at 250 mg/kg and more, as did TRCE did at 1000 mg/kg. These results show that TRCE and TECE affect various behaviors in mice and suggest that conflict behaviors are one of the most sensitive behavioral indicators of the effects of these substances. The toxicological profiles of TRCE and TECE with respect to behavioral effects were very similar, and they can be classified in a single category.

Abstract  Dichloroacetate (DCA) and trichloroacetate (TCA) are metabolites of the environmental contaminant trichloroethylene (TCE) that are thought to be responsible for its hepatocarcinogenicity in B6C3F1 mice. TCA and DCA induce peroxisomal proliferation and are mitogenic in rodent liver. The susceptibility of humans to TCA- and DCA-induced hepatocarcinogenesis is unknown. The current studies were aimed at using both primary and long-term human hepatocyte cultures to study the effects of TCA, DCA, and a potent peroxisome, proliferator, WY-14,643, on peroxisomal activity and DNA synthesis in human hepatocytes. Peroxisome proliferation, as assessed by palmitoyl-CoA oxidation activity, was below the limit of detection in all human cell lines tested. However, the human cell lines did display small but significant increases in CYP450 4A1 1 levels following treatment with WY-14,643 (0.1 mmol/L), indicating that the CYP 4A11 gene may be regulated by peroxisome proliferator-activated receptor alpha in humans. Similarly to their effect in rodent hepatocyte cultures, TCA and DCA were not complete mitogens in human hepatocyte cultures. In fact, DNA synthesis tended to be significantly decreased following treatment of the cells with WY-14,643, TCA, or DCA. In contrast to rodent hepatocyte responses, TCA and DCA did not increase palmitoyl-CoA oxidation and caused a decrease in DNA synthesis in human hepatocyte cultures, suggesting that humans may not be susceptible to TCA- and DCA-induced hepatocarcinogenesis

Abstract  Peroxisome proliferators, which function as peroxisome proliferator-activated receptor alpha (PPARalpha) agonists, induce peroxisomal, microsomal, and mitochondrial fatty acid oxidation enzymes, in conjunction with peroxisome proliferation, in liver cells. Sustained activation of PPARalpha leads to the development of liver tumors in rats and mice. The assertion that synthetic PPARalpha ligands pose negligible carcinogenic risk to humans is attributable, in part, to the failure to observe peroxisome proliferation in human hepatocytes. To explore the mechanism(s) of species-specific differences in response to PPARalpha ligands, we determined the functional competency of human PPARalpha in vivo and compared its potency with that of mouse PPARalpha. Recombinant adenovirus that expresses human or mouse PPARalpha was produced and administered intravenously to PPARalpha-deficient mice. Human as well as mouse PPARalpha fully restored the development of peroxisome proliferator-induced immediate pleiotropic responses, including peroxisome proliferation and enhanced expression of genes involved in lipid metabolism as well as nonperoxisomal genes, such as CD36, Ly-6D, Rbp7, monoglyceride lipase, pyruvate dehydrogenase kinase-4, and C3f, that have been identified recently to be up-regulated in livers with peroxisome proliferation. These studies establish that human PPARalpha is functionally competent and is equally as dose-sensitive as mouse PPARalpha in inducing peroxisome proliferation within the context of mouse liver environment and that it can heterodimerize with mouse retinoid X receptor, and this human PPARalpha-mouse retinoid X receptor chimeric heterodimer transcriptionally activates mouse PPARalpha target genes in a manner qualitatively similar to that of mouse PPARalpha

Abstract  This paper presents formaldehyde and volatile organic compounds (VOC) concentrations, potential sources and impact factors in 100 homes. The 24-h average formaldehyde concentration in 37 homes exceeded the good class of the Hong Kong Indoor Air Quality Objectives (HKIAQO), whereas the total VOCs concentration in all homes was lower than the HKIAQO. Compared to other East Asian cities, indoor formaldehyde and styrene in Hong Kong was the highest, reflecting that the homes in Hong Kong were more affected by household products and materials. The formaldehyde concentration in newly built apartments was significantly higher than that in old buildings, whereas no relationship between the concentration and the building age was found for VOCs. There was no difference for formaldehyde and toluene between smoking and non-smoking homes, suggesting that cigarette smoking was not the major source of these two species. Homes of a couple with a child had higher formaldehyde and acetic acid concentrations, while homes with more than three people had higher concentrations of 1-butanol, heptane and d-limonene. When shoes were inside the homes, heptane, acetic acid, nonane and styrene concentrations were statistically higher than that when shoes were out of the homes. Furthermore, higher levels of 1,2,4-trimethylbenzene, styrene, nonane and heptane were found in gas-use families rather than in electricity-use homes. PRACTICAL IMPLICATIONS: Long-term exposure to formaldehyde and volatile organic compounds (VOC) in indoor environments may cause a number of adverse health effects such as asthma, dizziness, respiratory and lung diseases, and even cancers. Therefore, it is critical to minimize indoor air pollution caused by formaldehyde and VOCs. The findings obtained in this study would significantly enhance our understanding on the levels, emission sources and factors which affect indoor concentrations of formaldehyde and VOCs. The results can help housing designers, builders, home residents, and housing department of the government to improve indoor air quality (IAQ) by means of appropriate building materials, clean household products and proper life styles. It can also help policy makers reconcile the IAQ objectives and guidelines.

Abstract  The developmental toxicity of two trimethylbenzene isomers, mesitylene (1,3,5-trimethylbenzene) and pseudocumene (1,2,4-trimethylbenzene) was studied in Sprague-Dawley rats following inhalation exposure. Pregnant rats were exposed whole body to vapours of mesitylene (0, 100, 300, 600, and 1200 ppm) or pseudocumene (0, 100, 300, 600, and 900 ppm), 6h/day, on gestational days (GD) 6 through 20. Significant decrease in maternal body weight gain and food consumption was observed at concentrations of 300 ppm mesitylene, 600 ppm pseudocumene, or greater. Fetal toxicity, expressed as significant reduction in fetal body weight, occurred at 600 and 1200 ppm mesitylene, and at 600 and 900 ppm pseudocumene. There was no evidence of embryolethal or teratogenic effects following inhalation exposure to either of these chemicals. In summary, the no-observed-adverse-effect-level (NOAEL) for maternal toxicity was 100 ppm for mesitylene and 300 ppm for pseudocumene, and the NOAEL for developmental toxicity was 300 ppm for mesitylene and pseudocumene.

Abstract  1. Single doses of 1,2,4-trimethylbenzene (124TMB) or 14C-124TMB were administered orally to rats for metabolism and distribution studies. 2. 14C-124TMB was rapidly and widely distributed throughout the body with the highest levels in adipose tissue. No other preferential uptake of 14C-124TMB by any of the organs or tissues examined was evident. 3. Tissue levels declined rapidly within 24 h after dosage, with more than 99% of the administered radioactivity recovered in the urine during this period. 4. A complex mixture of isomeric trimethylphenols, dimethylbenzyl alcohols, dimethylbenzoic acids and dimethylhippuric acids excreted in the urine accounted for more than 81% of the administered dose. The major metabolites were 3,4-dimethylhippuric acid (30.2% dose), 2,4-dimethylbenzyl alcohol (12.7% dose, primarily as sulphate and glucuronide conjugates) and 2,5-dimethylbenzyl alcohol (11.7% dose, primarily as sulphate and glucuronide conjugates).

Abstract  The objective of this study was to evaluate the toxicokinetics and metabolism of pseudocumene after inhalation exposure. Male Wistar rats were exposed to pseudocumene vapors at nominal concentrations of 25,100 or 250 ppm in the dynamic inhalation chambers for 6 h. Blood samples were collected during (between 1st and 6th h) and after exposure (betwen 6th min and 6th h). Blood concentrations of pseudocumene were estimated by gas chromatography using the headspace technique. During a six-hour exposure, the concentration of pseudocumene in blood increased rapidly within the first 2 h reaching then a plateau. The elimination of pseudocumene from blood followed an open two-compartment model. Urine samples were collected from the exposed animals, and metabolites were analyzed by gas chromatography with a flame ionization detector. Three metabolites were measured in the rat urine after hydrolysis: 3,4-dimethylbenzoic acid (3,4-DMBA), 2,4-dimethylbenzoic acid (2,4-DMBA) and 2,5-dimethylbenzoic acid (2,5-DMBA). A significant linear correlation was found between the level of exposure and the concentration of dimethylbenzoic acids. The enzyme kinetics of pseudocumene biotransformation was calculated by Lineweaver-Burk equation. Metabolic constants, Km (mg/l) and Vmax (mg/h/kg), the parameters for pseudocumene biotransformation by rats were estimated (3,4-DMBA - Km = 28, Vmax = 96; 2,4-DMBA - Km = 7, Vmax = 25; 2,5-DMBA - Km = 7, Vmax = 23).

Abstract  A physiologically based toxicokinetic model was developed for inhalation exposure of 1,2,4-trimethylbenzene (TMB) in man. The model consists of six compartments for TMB and one compartment for the metabolite 3,4-dimethylhippuric acid (DMHA). Based on previous experimental findings from human exposures to TMB, liver metabolism was divided in two pathways, one of the first order and one of the Michaelis-Menten type. Muscle tissue was split in two compartments to account for working and resting muscle tissues during bicycle exercise. The model was used to investigate how various factors influence potential biomarkers of exposure, i.e., TMB in blood and exhaled air and DMHA in urine. Increasing the work load from rest to moderate exercise (100 W) more than doubled all biomarker levels end of shift. The effect on next morning levels was even more pronounced, illustrated by a fivefold increase in the DMHA excretion rate. Simulations of five daily 8-h exposures suggest that biomarker levels end of shift remain fairly constant whereas the levels prior to shift increase gradually during the week. This suggests that end of shift levels reflect the exposure of the same day whereas levels Friday morning reflect exposure during the entire working week. Simulations with randomly generated exposures show that the variability due to fluctuating exposure is lower next morning than end of shift. End of shift exhalation rate of TMB is more sensitive to fluctuation than TMB in venous blood and DMHA in urine. Biomarker levels for 25 ppm exposure at different sampling times are given.

Abstract  The objective of this study was to determine the uptake and disposition of inhaled trimethylbenzenes (TMBs) in man. The toxicokinetics were studied in 10 male, healthy volunteers exposed to TMB vapor in an exposure chamber for 2 hr during a work load of 50 W. The subjects were exposed on four occasions to 25 ppm of 1,2,4-TMB, 1,2,3-TMB, and 1,3,5-TMB, and to 2 ppm of 1,2,4-TMB. The TMB isomers were analyzed in blood, urine, and exhaled air by gas chromatography. The relative respiratory uptake was in the range 56-64%. The elimination of TMBs was moderate compared to other aromatic solvents, with a total blood clearance of 0.6-1.0 liter hr(-1) kg(-1). Large volumes of distribution (30-39 liters/kg) and long terminal half-lives of the TMBs in blood (78-120 hr) imply extensive accumulation in adipose tissue. Exhalation during and postexposure accounted for 20-37% of the absorbed amount, whereas the urinary excretion of unchanged TMBs was low (< or = 0.002%). The kinetics of 1,2,4-TMB seemed linear up to 25 ppm. In addition, the occurrence of symptoms of acute effects was studied by means of a questionnaire. The subjects rated the degree of irritation and central nervous system symptoms on a 100-mm visual analog scale. No discomfort was reported at these exposure conditions.

Abstract  The objective of this study was to compare the toxicokinetics of inhaled 1,2,4-trimethylbenzene (1,2,4-TMB) in man after exposure to white spirit with that observed after exposure to 1,2,4-TMB alone. TMBs occur mainly in petroleum products and the TMBs or their metabolites have been suggested as suitable biomarkers of exposure to white spirit and other distillation products. The toxicokinetics were studied in 9 male, healthy volunteers exposed to solvent vapours in an exposure chamber for 2 h during a work load of 50 W. The subjects were exposed to 11 mg/m3 of 1,2,4-TMB on two occasions; during exposure to 1,2,4-TMB vapour alone and during exposure to 300 mg/m3 of white spirit. The 1,2,4-TMB isomer was analyzed in blood and exhaled air by gas chromatography. In addition, a major urinary metabolite of 1,2,4-TMB, 3,4-dimethylhippuric acid (3,4-DMHA), was analyzed by high performance liquid chromatography. Further the occurrence of acute effects was studied by means of a questionnaire. Irritation and central nervous system symptoms were recorded by ratings on a 100-mm visual analogue scale. Blood levels of 1,2,4-TMB and excretion rates of 3,4-DMHA in urine were markedly elevated both during and after exposure to white spirit as compared to exposure to TMB alone. Thus, it appears that components in white spirit inhibit the metabolic elimination of 1,2,4-TMB. This should be considered in biological exposure monitoring as well as in risk assessment. No irritation or central nervous system effects were reported at these conditions.

Abstract  The vascular aquatic plant Lemna gibba (duckweed) was exposed during seven days to lead (Pb) at concentrations ranging from 50 to 300 mg/L in a greenhouse with controlled photoperiod and temperature. The effects of Pb on growth of Lemna gibba were examined during 13 days in the same experimental design. The maximum accumulation of lead by Lemna gibba occurs during the third day in the 50 mg/L test, and at the sixth day, lead in all test concentrations produces approximately a 100% inhibitory effect on duckweed growth. In all tests, the maximum relative growth rates were achieved on the third day and then, the toxicity effects were: 59.3% total soluble starch reduction; 94.7% total soluble proteins reduction; 246% increase in total soluble amino acids; 50% increase in total soluble sugars and an 18.2% increase in total phenols. This experiment showed that the transfers of Pb from nutritive solution to plants were fast. Nevertheless, Pb produced toxic effects on Lemna gibba; however duckweed was able to remove Pb at the experimental concentrations used.

Abstract  The tumorigenicity of chloral hydrate (CH), trichloroacetic acid (TCA), trichloroethanol (TCE), malondialdehyde (MDA), crotonaldehyde, acrolein, and 4-hydroxy-2-nonenal (HNE) was tested in the B6C3F(1) neonatal mouse. Mice were administered i.p. injections of CH (1000, 2000, 2500, and 5000 nmol per animal), TCA (1000 and 2000 nmol), TCE (1000 and 2000 nmol), MDA (1500 and 3000 nmol), crotonaldehyde (1500 and 3000 nmol), acrolein (75 and 150 nmol), and HNE (750 and 1500 nmol) at 8 and 15 days of age. At 12 months, only male mice treated with the positive control chemicals, 4-aminobiphenyl (500 and 1000 nmol) and benzo[a]pyrene (150 and 300 nmol), had incidences of tumors in the liver significantly higher than the solvent control. Additional male mice were dosed as described above and their livers were excised at 24, 48 h, and 7 days after the final dose. Liver DNA was isolated and analyzed by 32P-postlabeling/high-performance liquid chromatography (HPLC) and HPLC/electrochemical detection for MDA-derived adduct (M(1)G) and 8-oxo-2'-deoxyguanosine (8-OHdG) formation, respectively. At 24 and 48 h after the final dose, CH- and TCA-treated mice exhibited significantly higher M(1)G levels than the controls. 8-OHdG formation was also induced by CH, TCA, and MDA. These results suggest that under these experimental conditions the B6C3F(1) neonatal mouse is not sensitive to carcinogens that induce an increase in endogenous DNA adduct formation through lipid peroxidation or oxidative stress.

Abstract  Some farmland in Shenyang had been irrigated with industrial wastewater since 1962. Although wastewater irrigation was ceased in 1992, soil had been heavily polluted by heavy metals, especially by Cd. For better understanding processes of soil-heavy metal interactions, in particular, the mobility and retention mechanism of heavy metal in soil, a study on the transport and fate of heavy metals in soil zones from Shenyang suburb was carried out by column leaching tests in laboratory. Breakthrough curves of Pb, Cd, Cr(VI) and As(V) fitted by Thomas model and Yoon-Nelson model. The results of fitted breakthrough curves showed that transport rates of the four heavy metals in the soil zones followed the order: Cr(VI)>As(V)>Cd>Pb, which indicated that Cr(VI) was much more mobile, and Pb was comparatively unmovable. Cr in effluents and As were almost entirely Cr(VI) and As(V), respectively, and no Cr(III) and As(III) was ever detected during the leaching tests. The contents of Pb, Cd, Cr and As in leached soils decreased in the order of Pb>Cd>Cr>As, which suggested that adsorption ability of soil to Pb was greatest and to As was least. The methods of selective sequential extraction and solvent extraction were used to determine the fractions of Pb, Cd, Cr, As and the valent states of Cr, As [Cr(VI) or Cr(III), As(V) or As(III)] in original soils and in leached soils. After leaching tests, the relative and absolute concentrations of exchangeable, carbonate, Fe-Mn oxide and organic fraction of each element were all increased, which enhanced the potential mobility and risk of Pb, Cd, Cr and As to soil /groundwater system. The relative concentrations of Cr(III) and As(III) in different depth of the soil zones after leaching tests were increased by about 6.0% and 5.6%, respectively. Cr(III) and As(III) tended to be adsorbed by soils, which reduced the mobility of them into groundwater.

Abstract  Environmental concentrations of toxic substances are not necessarily constant but fluctuate over time. Periods of intense exposure might be followed by episodes with a relatively low or no exposure, in principle allowing exposed organisms to recover from toxic injury. The growth reproduction assay with the limnic vascular plant Lemna minor allows for convenient studies on the time dependence of the aquatic toxicity of chemicals. Here we report on a study with four priority metals (Zn, Cu, Ni, Cd). Aims of the study were to determine the impact of the exposure duration on the observed toxicities and to determine the potential for recovery. The bioconcentrations of the test metals were recorded during the exposure in order to analyse, whether changes in the internal concentrations are a governing factor for the dynamics of toxicity. After an exposure of 7 days, Cd and Cu showed the highest toxicity to Lemna (EC50's of 1.9 and 9.7 mu M respectively), while Ni and Zn had a slightly lower toxicity (EC50's of 56.3 and 46.1 mu M respectively). Additionally, Zn showed a severely delayed toxicity and the exposed plants did not recover even 7 days after the exposure had ended. This is in sharp contrast to the other test metals, for which a considerable recovery was observed. These results indicate the necessity to more thoroughly consider the dynamics of toxicity, instead of recording toxic effects only after a constant exposure over a fixed time.

Abstract  The present study examines the influence of Ca2+ as (CaSO4), dissolved organic carbon (DOC) and pH on chronic water-borne lead (Pb) toxicity to the larval fathead minnow (Pimephales promelas) under flow-through conditions. The 30 day LC50 for low hardness basic test water (19 mg CaCO3 L− 1) was 39 (range: 27–51) μg dissolved Pb L− 1 and was greatly increased by increasing concentrations of CaSO4 and DOC to as much as 1903 (range: 1812–1992) μg dissolved Pb L− 1. Both reduced and increased pH (6.7 and 8.1, respectively) compared to control pH of 7.4 appeared to increase Pb toxicity substantially. Whole body Pb accumulation did not reflect water chemistry and thus exhibited no correlation with Pb induced mortality. One possible explanation for this lack of correlation is that mortality occurred predominantly during the first 4–6 days of exposure, whereas Pb accumulation was determined in surviving fish at the end of 30 days of exposure. Chronic Pb exposure resulted in a general iono-regulatory disturbance affecting K+, Na+ and Ca2+ homeostasis. However, recovery of Na+ and K+ levels and reversal of effects on Ca2+ homeostasis during continued exposure strongly suggest fathead minnow can acclimate to Pb. The gills accumulate the highest Pb concentrations during chronic exposure but the skeleton contains the largest mass of Pb by contributing up to not, vert, similar 80% of whole body Pb. In conclusion, water chemistry characteristics like Ca2+ and DOC should be considered for chronic water quality criteria.

Abstract  Biosorptions the effective method for the removalf heavy metalons from wastewaters. Results are presented showing the sorptionf Pb(II) from solutions by biomassf commonly available, filamentous green algae Spirogyra sp. Batch experiments were conducted toetermine the biosorption propertiesf the biomass andt wasbserved that the maximum adsorption capacityf Pb(II)on was around 140mgmetal/gf biomass at pH 5.0n 100min with 200mg/Lfnitial concentration. Temperature changen the range 20-40egrees C affected the adsorption capacity and the naturef the reaction was found to be endothermicn nature. Uptake kinetics follows the pseudo-second-order model and equilibriums wellescribed by Langmuirsotherm. Isotherms have been used toetermine thermodynamic parametersf the process, viz., free energy change, enthalpy change and entropy change. Various propertiesf the algae, as adsorbent, exploredn the characterization part were chemical compositionf the adsorbent, thermal analysis by TGA, surface area calculation by BET method, surface morphology with scanning electron microscopemages and surface functionality by FTIR. FTIR analysisf algal biomass revealed the presencef amino, carboxyl, hydroxyl and carbonyl groups, which are responsible for biosorptionf metalons. The resultsndicated that the biomassf Spirogyra sp.s an efficient biosorbent for the removalf Pb(II) from aqueous solutions.

Abstract  The aimf the present studys to evaluate the seasonal fluctuationf heavy metalsn thesopod Porcellio laevis at four uncontaminated subtropical locations. This study was carriedut at fourifferent field sitesn Assiut, Egypt. The concentrationsf cadmium, lead, copper, and zincn animal, soil, and litter (mug/gry weight) were monthly recordeduring the period from June 2002 till May 2003. There was littleifferencen metal accumulation trends between the sites. In general, thesopod showed significantncreased Pb and Zn concentrationuring summer and spring months, whereas this was not the case for Cd and Cu. The bioaccumulation (BAF) and bioconcentration factors (BCF)f the metals revealed marked seasonal changes throughout the year. Generally, BAFf metals were higheruring summer and spring, and BCF were higheruring summer and autumn. Comparing the metal accumulation with climatic fluctuations (measured)t was speculated that temperature was the main factor causing seasonal fluctuationsf thenternal metal concentrationn thesopod.

Abstract  Theiversityf nematode-trapping fungi (NTF)n two lead (Pb) minesn Yunnan Province, China wasnvestigatedn 2004. In total, 20 species belonging to five genera weredentified from 500 samples collected at the Lanping and the Huize mines. Pb concentrations ranged from 216 approximately 7,150 mg/kg for the former and 132 approximately 13,380 mg/kg for the latter, respectively. The fungi wereividednto five groups basednifferent trapping mechanisms. The trapping-net producer group contained the largest numberf species, with nine. Two predators, Dactylellina ellipsosporum and Arthrobotrysligospora, were found at frequenciesf 32.85% and 15.41%, respectively. Theiversityndexesf NTF were positively correlated with Pb pollution levelsn both the Lanping Mine (r=0.66) and the Huize Mine (r=0.72), suggesting that theistributionf NTF was not negatively affected by Pb contamination. For most strainsf a given species, there was no significantifference (P>0.01)n the Pb tolerance between the strainssolated from habitats with lowr high Pb concentrations. However, Pb toxicity exerted adverse effectsn trap formation and predacious capabilityf fungi. Weiscuss the possible metal tolerance mechanisms and their relationships to the survival strategyf NTFn Pb-polluted environments.

Abstract  The effectf two earthworm species, Lumbricus rubellus and Eisenia fetida,n the fractionation/bioavailabilityf Pb and Zn before and after soil leaching with EDTA was studied. Four leaching steps with total 12.5 mmol kg(-1) EDTA removed 39.8% and 6.1%f Pb and Zn, respectively. EDTA removed Pb from all soil fractions fairly uniformly (assessed using sequential extractions). Zn was mostly presentn the chemicallynert residual soil fraction, which explainsts poor removal. Analysisf earthworm casts and the remainderf the soilndicated that L. rubellus and E. fetida actively regulated soil pH, butid not significantly change Pb and Zn fractionationn non-remediated and remediated soil. However, the bioavailabilityf Pb (assessed using Ruby's physiologically based extraction test)n E. fetida casts was significantly higher thann the bulkf the soil. In remediated soil the Pb bioavailabilityn the simulated stomach phasencreased by 5.1 times.

Abstract  S-(1,2-Dichlorovinyl)glutathione and S-(1,2-dichlorovinyl)-DL-cysteine are potent nephrotoxins. Agents that inhibit gamma-glutamyl transpeptidase, cysteine conjugate beta-lyase, and renal organic anion transport systems, namely L-(alpha S,5S)-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid (AT-125), aminooxyacetic acid, and probenecid, respectively, protected against S-conjugate-induced nephrotoxicity. Furthermore, S-(1,2-dichlorovinyl)-DL-alpha-methylcysteine, which cannot be cleaved by cysteine conjugate beta-lyase, was not nephrotoxic. These results strongly support a role for renal gamma-glutamyl transpeptidase, cysteine conjugate beta-lyase, and organic anion transport systems in S-(1,2-dichlorovinyl)glutathione- and S-(1,2-dichlorovinyl)cysteine-induced nephrotoxicity.

Abstract  Trichloroethylene, a solvent used in a variety of industrial settings for more than 60 years, has caused adverse health effects on the central and peripheral nervous system, the skin, liver, kidney, and heart. Three men have shown relatively unusual manifestations secondary to exposure to trichloroethylene in degreasing operations in the jewelry industry. Toxic encephalopathy, hepatitis, and carpal spasm occurred among young, healthy workers. Clinical and laboratory data, including measurement of urinary trichloroacetic acid concentrations, are presented.

Abstract  The efficiency of poplar (Populus nigra L.xPopulus maximowiczii Henry.) was assessed during a two-year chemically enhanced phytoextraction of metals from contaminated soils. The tested metal mobilizing agents were EDTA (ethylenediaminetetraacetic acid) and NH4Cl. EDTA was more efficient than chlorides in solubilizing metals (especially Pb) from the soil matrix. The application of chlorides only increased the solubility of Cd and Zn. However, the increased uptake of metals after the application of higher concentrations of mobilizing agents was associated with low biomass yields of the poplar plants and the extraction efficiencies after the two vegetation periods were thus comparable to the untreated plants. Additionally, the application of mobilizing agents led to phytotoxicity effects and increased mobility of metals. Higher phytoextraction efficiencies were observed for Cd and Zn compared to Pb and Cu. Poplars are therefore not suitable for chemically enhanced phytoextraction of metals from severely contaminated agricultural soils.

Abstract  #A method was developed to simulate the human gastrointestinal environment and to estimate bioavailability of arsenic in contaminated soil and solid media. In this in vitro gastrointestinal (IVG) method, arsenic is sequentially extracted from contaminated soil with simulated gastric and intestinal solutions. A modified IVG-AB method, where iron hydroxide gel is used to simulate the absorption of arsenic, was also evaluated. Fifteen contaminated soils collected from mining/smelter sites ranging from 401 to 17 460 mg As kg-1 were analyzed. In vitro results were compared with in vivo relative bioavailable arsenic (RBA) determined from dosing trials using immature swine which ranged from 2.7 to 42.8% RBA. Arsenic extracted by the IVG and IVG-AB methods was not statistically different than RBA arsenic measured by the in vivo method. Arsenic extracted by the IVG stomach and intestinal phases was linearly correlated (r = 0.83 and 0.82, respectively) with in vivo arsenic (P < 0.01). Similarly, the IVG-AB method was linearly correlated (r = 0.79) with in vivo bioavailable arsenic (P < 0.05). All IVG methods extracted similar amounts of arsenic and provided estimates of bioavailable As in contaminated media. The IVG method may aid in the design and cost-effectiveness of remedial strategies of arsenic-contaminated sites.