Abstract  As(V)- and Cr(VI)-resistant bacteria were isolated from the industrial city Kasur, Pakistan. The 16S rRNA gene sequencing revealed that the highly resistant bacteria KS2-1, KS2-2, MWM81, and KSKE41 were related to Bacillus sp., Rhodococcus sp., Cellulosimicrobium sp., and Exiguobacterium sp., respectively. KS2-1 reduced As(V) up to 94% and MWM81 reduced Cr(VI) up to 45%. Co-cultures of KS2-1 and KS2-2 reduced As(V) up to 98%, whereas co-cultures of MWM81 and KSKE41 reduced Cr(VI) up to 55%. Bacteria living in same niches could work together to degrade contaminants which were common toxicants for them.

Abstract  Previous studies investigating the exposure to metal(loid)s of populations living in the Panasqueira mine area of central Portugal found a higher internal dose of elements such as arsenic, chromium, lead, manganese, molybdenum and zinc in exposed individuals. The aims of the present study were to evaluate the extent of genotoxic damage caused by environmental and occupational exposure in individuals previously tested for metal(loid) levels in different biological matrices, and the possible modulating role of genetic polymorphisms involved in metabolism and DNA repair. T-cell receptor mutation assay, comet assay, micronucleus (MN) test and chromosomal aberrations (CA) were performed in a group of 122 subjects working in the Panasqueira mine or living in the same region. The modifying effect of polymorphisms in GSTA2, GSTM1, GSTP1, GSTT1, XRCC1, APEX1, MPG, MUTYH, OGG1, PARP1, PARP4, ERCC1, ERCC4, and ERCC5 genes was investigated. Significant increases in the frequency of all biomarkers investigated were found in exposed groups, however those environmentally exposed were generally higher. Significant influences of polymorphisms were observed for GSTM1 deletion and OGG1 rs1052133 on CA frequencies, APEX1 rs1130409 on DNA damage, ERCC1 rs3212986 on DNA damage and CA frequency, and ERCC4 rs1800067 on MN and CA frequencies. Our results show that the metal(loid) contamination in the Panasqueira mine area induced genotoxic damage both in individuals working in the mine or living in the area. The observed effects are closely associated to the internal exposure dose, and are more evident in susceptible genotypes. The urgent intervention of authorities is required to protect exposed populations.

Abstract  HEEP COPYRIGHT: BIOL ABS. The impact of heavy metal pollutants on earthworms was studied by observing mortality and reproduction in O. pattoni exposed to Cr (VI) and Hg (II) at levels varying from 0-25 ppm. While both metals induced significant mortality at all levels of exposure, they also caused an enhancement in reproduction, as revealed by the higher production of juveniles and bits in metal-exposed animals compared to controls. The significance of the results in environmental management was discussed.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. Recent investigations of the soil chemistry of chromium suggest that chromium may exist in two forms: (1) the chromate anion and (2) the chronic cation. The present study used chromate absorption isotherms on selected horizons from six soils differing in texture. pH, and organic carbon. Generally, higher levels of organic carbon were associated with enhanced chromate adsorptivity, while o-phosphate, as a co-solute, inhibited chromate adsorptivity. Organic carbon was inferred to easily reduce chromate, giving appearances of a high selectivity. Chromate adsorption in organic carbon impoverished horizons is proposed to be a combination of anionic reduction by Fe(II)-Mn(II) and an anionic competitive exchange reaction.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. An aluminum window manufacturing plant in Malden, Missouri (USA) contaminated a sandy soil with blue-green Cr-Al coprecipitates from effluent suspensions. A bimodal Cr distribution with peak concentrations at the surface and at approximately 1 m demonstrates Cr mobility in this soil. Elevated Cr at 1 m is associated with increased clay content and Mn(II). Chromium's mobility is attributed to a rapid leaching of chromate at the time of deposition and the possible very slow dissolution of Cr(OH)4-. Significant amounts of chromate were likely reduced to Cr(III) oxyhydroxides because of organic matter oxidation and hydrolysis.

Abstract  Biosis copyright: biol abs. rrm wastewater treatment ph pollution control

Abstract  BIOSIS COPYRIGHT: BIOL ABS. Chromium(VI) is one of seven elements which is classified in the fertilizer industry as being harmful to plants and biological systems. Phosphate rocks represent the raw material for complex fertilizer production in the world. This paper investigates for the first time the determination of total chromium in phosphate rocks by ion chromatography. The developed analytical method involves the digestion of phosphate rocks with nitric acid followed by sample treatment of the resulting solution. The d erent phosphate rocks with atomic absorption spectrometry and inductively coupled plasma atomic emission spectrometry techniques, and cross-analysis data against an internationally certified phosphate rock standard were between 0.58 and 1.45%. Calibration curve between 0.2 and 0.9 mug/ml was excellent, and the method has a detection limit for Cr(VI) of 0.05 ng. The developed method offers a fast, a reliable and an alternative procedure for the determination of total chromium in p

Abstract  BIOSIS COPYRIGHT: BIOL ABS. A method for the simultaneous determination of Cr(III) and Cr(VI) in water samples is described. The different reaction products of Cr(III) and Cr(VI) species with ammonium pyrrolidinedithiocarbamate (APDC) are extracted with ethyl acetate and determined by reversed phase HPLC using UV-detection. The procedure is optimized and its detection limit accordingly improved as compared to literature data. The detection limits achieved are 2.4 mug/l for Cr(III) and 2.1 mug/l for Cr(VI) and the calibration curves are linear between 5 mug/l and 5000 mug/l. For the speciation of Cr, APDC was demonstrated to be more suitable as chelating agent than sodium diethyldithiocarbamate (NaDDC). The procedure was applied to the determination or both Cr species in galvanic waste waters and its accuracy was approved by comparing the results (at the 100 mug/l level) with those of a photometric determination of Cr(VI) species.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. Speciation of Cr(III) and Cr(VI) based on the formation of different complexes with ammonium-pyrrolidinedithioate (APDC) in a continuous flow technique and their preconcentration using solid phase extraction (SPE) have been elaborated and applied to the analysis of waste waters from the galvanic industry. The Cr complexes were separated and determined using reversed phase-high performance liquid chromatography (RP-HPLC) coupled to different detection methods, namely UV-detection, graphite furnace-atomic absorption spectrometry (GF-AAS) and inductively coupled plasma mass spectrometry with hydraulic high pressure nebulization (HHPN-MS). After optimization the detection limits for Cr(III) and Cr(VI) of all methods are at the mug l-1 level and the precision in terms of RSD is 5% (cCr = 10 mug l-1, N = 10). The procedure was applied to the determination of Cr(III) and Cr(VI) at the mug l-1 level in galvanic waste waters, and its accuracy was approved by comparing the result

Abstract  Biosis copyright: biol abs. rrm environmental samples urine nutrition toxicity

Abstract  Biosis copyright: biol abs. rrm soil pollution soil reclamation extraction

Abstract  In response to a request from the director of Mainstreet Enterprises (SIC-3273), a nonprofit rehabilitation sheltered workshop in Lebanon, Indiana, an evaluation was made of the occurrence of benign breast tumors among female workers exposed to concrete dust during packaging of dry powdered concrete mortar mix (Fix-Crete). Bulk samples of the finished Fix-Crete were collected to be analyzed for asbestos (1332214), crystalline silica (7631869), hexavalent chromium (18540299), and total chromium (7440473) content. Hexavalent chromium was found at concentrations of 32 micrograms per gram (microg/g) of bulk material. Total chromium, asbestos and silica were not detectable. Respirable particulate concentrations ranged from 0.8 to 2.3 milligrams per cubic meter (mg/m3). Total particulates ranged from 2.9 to 34.3mg/m3. After minor modifications of the ventilation system were made, retesting indicated personal breathing zone and air samples for respirable particulates averaged 0.5 and 1.1mg/m3, respectively. Total particulates ranged from 1.7 to 13.8mg/m3. No significant differences in the prevalence of benign breast tumors was noted in supervisors working on the concrete powder process when compared to those who did not work in this area. The authors conclude that there was an exposure to dust for one task. No evidence was found to link the occurrence of benign breast tumors to chemical exposures at the facility. The authors recommend that a further reduction of the mixer operator's exposure be brought about through effective engineering controls. Respirators should be used where appropriate. Vacuum cleaning equipment should be used to collect debris from the clothing of personnel and rehabilitees instead of compressed air. Protective gloves and cleaning and washing facilities should be made available.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. A technique is described for selectively measuring the forms of chromium in freshwater samples, with detection limits of 21 ng L-1 for Cr(III), 4 ng L-1 for Cr(VI), and 8 ng L-1 for colloidal/organic Cr. Recovery of the Cr(VI) and Cr(III) spikes were consistently > 90%, but only about 70% for the added organic Cr. When the method was applied to samples from Lake Ontario, it was found that Cr(VI) made up 75-85% of the dissolved Cr and that Cr(III) was consistently below the analytical detection limit. About 10% of the dissolved Cr was in the colloidal/organic form. Average concentrations of total dissolved Cr in the epilimnetic waters were found to be 69 ng L-1 in Lake Superior, 136 ng L-1 in Lake Erie, and 351 ng L-1 in Lake Ontario. The increasing concentration of Cr down the Great Lakes watershed reflects the conservative geochemical behavior of Cr(VI) and the increasing input of Cr from industrial and municipal sources.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. Based on a scientific study of the deposition of radioactive 51CrO42- species on ignited microcrystalline sulfates of lead, barium, and strontium along with their subsequent elution, a new experimental procedure for the concentration of aqueous extracts for microgram quantities of chromate species is developed. The feasibility of the procedure has been studied radiometrically on the basis of a systematic examination of the working conditions, e.g., carrying efficiency as a function of pH of the aqueous medium lattice/nonlattice ionic concentration, amount of carrier, carrying capacity of the carrier, and extraction of activity adsorbed under suitable experimental conditions. In principle, the procedure consists of two stages: first, the radioactive tracer species in a dilute aqueous solution is carried out under specified experimental conditions on a small quantity of ignited selected carriers; second, the carried activity can be largely leached out in a minimal amount

Abstract  Biosis copyright: biol abs. rrm salmonella microsome liquid culture assay respiratory cancer frameshift mutation cell-particle interaction

Abstract  BIOSIS COPYRIGHT: BIOL ABS. MetPAD, a bioassay for the specific determination of heavy metal toxicity, was evaluated for toxicity assessment of industrial effluents. It was shown that MetPAD does not respond to organic toxicants, but is sensitive to heavy metals. Six of nine industrial effluents were shown to be toxic using MetPAD. Chemical analyses of the industrial effluents confirmed the presence of heavy metals. If run concurrently with another test for general toxicity test (for example, Microtox), MetPAD can be a suitable complimentary assay for the specific determination of heavy metal toxicity.

Abstract  Biosis copyright: biol abs. rrm abstract human fecal mutagens 4 nitroquinoline 1-oxide ethyl methanesulfonate methyl methanesulfonate n methyl-n'-nitro-n-nitrosoguanidine chromium-vi carcinogens

Abstract  Nephrotoxic effects of dimethyl-sulfoxide (67685) (DMSO) were studied in humans and laboratory animals. Twenty one patients (17 males) and chronic stable neurologic deficits related to traumatic spinal cord injury were infused intravenously (iv) with 1 gram per kilogram (g/kg) DMSO for 10 minutes to 24 hours. Some patients were infused for 3 days. Parameters of kidney function such as blood urea nitrogen (BUN), serum creatinine, creatinine clearance, hemoglobin, myoglobin, urinary protein, glucose, and specific gravity were determined. No changes from baseline in BUN, serum, creatinine, and creatinine clearance were seen. Some hemoglobinuria was observed; no myoglobin was present. No increase in qualitative urine protein or glucose, nor decrease in first morning specific gravity was observed. Male Fischer-rats were given 40 percent DMSO iv for 15 minutes for 3 days. The animals were killed 72 hours later. Serum creatinine was determined and the kidneys were examined for histopathological changes. Acute renal failure was induced in rats by injecting 5 to 20 milligrams per kilogram potassium-dichromate. The animals were given 0 or 1g/kg DMSO intraperitoneally. They were killed 1 to 5 days later and serum creatinine was determined. In rats given DMSO iv over 3 days, no renal histopathological changes were seen. No significant changes in serum creatinine concentration occurred. No evidence of added nephrotoxicity, as indicated by changes in serum creatinine, was noted in rats with dichromate induced kidney failure given DMSO, compared with those given potassium-dichromate alone. The authors conclude that DMSO causes no short term nephrotoxic effect. DMSO given iv is safe to use in patients who are prospective renal transplant donors.

Abstract  A group of twenty eight commercial compounds used in a leather and tannery factory (SIC-3111) near Florence, Italy, were tested for mutagenic response following the procedures described by Ames. The S9 fraction of livers from mice pretreated with phenobarbital and beta-naphthoflavone was used as an activating system. The chemical composition was available for about five products, others were listed by commercial names. Eight products gave positive responses in one or more strains of Salmonella-typhimurium, and five responded positively in Saccharomyces-cervisiae (D7). Tanning agents Chromitan-B (CB) and Chromitan-MS (CMS) contained chromium(III) (16065831), but no chromium(VI) (18540299) was detected. CB was toxic to Salmonella (TA-98) and (TA-1537), and CMS was toxic to (TA-1537). Bruno-Avival (BA) and Rosso-Avival (RA) dyes were mutagenic to (TA-98) and (TA-1537), and Rosso-HR (RHR) induced histidine revertants in (TA-100) and (TA-98). CB, CMS, BA, RA, and RHR induced gene conversion and point mutation in (D7) of Saccharomyces. Silican and Blancotan-PRV showed weak genetic effects, but neither contained chromium(III). Erhavit-A, a product used in the liming process, gave positive results using (TA-1535), with or without metabolic activation. None of the two disinfectants and nine oil resins induced mutagenic response in Salmonella strains or (D7). The authors conclude that these results suggest that environmental health risks should be studied with complex mixtures as they occur in the environment.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. Different digestion methods for the determination of heavy metals in urban sludges and its ashes are investigated utilizing two reference materials. The reference sludge and a real urban sludge are then utilized for incineration experiments to evaluate environmental impact both of residual ashes and of fumes produced during incineration. Material balances are performed to evaluate the distribution of heavy metals during the incineration experiments.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. A Cr(VI)-reducing culture was enriched from an anaerobic chemostat fed with synthetic media containing acetate and Cr(VI). The enriched culture was used for a series of batch tests to investigate several environmental factors affecting microbial Cr(VI) reduction. Under carbon-limiting conditions, the extent of Cr(VI) reduction proportionally depended on the carbon concentration and no reduction of Cr(VI) was observed in the absence of acetate. Cr(VI) reduction was also dependent upon the initial biomass level and the type of organic compounds. The developed model predicted Cr(VI) reduction well at different Cr(VI) concentrations. Sulfate at 120 mg SO42- or nitrate at 150 mg N/L slightly inhibited Cr(VI) reduction. Reduction of nitrate but not sulfate was observed along with Cr(VI) reduction. Cr(VI) was not reduced by the aerobically growing culture, and it was found that oxygen inhibitory effects on Cr(VI) reduction were reversible. The optimum pH and temperature for C

Abstract  Biosis copyright: biol abs. rrm literature review hexavalent chromium microbial reduction pollutant bioprocess engineering waste management waste treatment chromate

Abstract  BIOSIS COPYRIGHT: BIOL ABS. The potential for fixed-film bioreactors to reduce Cr(VI) was demonstrated using a Cr(VI)-reducing species, Bacillus sp. A bench-scale, packed-bed bioreactor was operated to steady-state conditions under a range of influent Cr(VI) concentrations (10-200 mg) and hydraulic detention times (6-24 h, clean bed) with near complete removal of Cr(VI). The steady-state Cr(VI) reduction efficiency was not affected by the influent Cr(VI) concentration or hydraulic detention time. Chromium mass balance analysis revealed that nearly all the Cr(VI) fed to the bioreactor was accounted for in the effluent as Cr(VI) and Cr(III). Total cell mass in the bioreactor decreased with increasing Cr(VI) loading rate, but it stabilized after a loading limit was reached (1016 mg of Cr(VI)/L day) when operated under 24 h hydraulic detention time. The bioreactor showed strong resilience by recovering from Cr(VI) overloading through reduction in influent Cr(VI) concentration.

Abstract  Chromium-containing industrial effluents are primarily responsible for environmental contamination by toxic and highly mobile, hexavalent chromium. The dilution plate-count method, using media amended with Cr(VI) at concentrations ranging from 0 to 1000 mg L-1, was used to compare the sizes of Cr(VI)-resistant bacterial populations from a soil contaminated with 25 100 mg kg-1 total Cr [12 400 mg kg-1 Cr(VI)] to those isolated from a slightly contaminated soil (99.6 mg kg-1 total Cr) and two other soils without any history of Cr contamination. Bacterial populations resistant to 500 mg L-1 Cr(VI) were isolated from all soils except the heavily contaminated soil. To determine whether Cr-resistant bacterial populations were indigenous to both the contaminated and the uncontaminated soils, enrichment cultures containing Cr(VI) at concentrations ranging from 0 to 1000 mg L-1 were employed. Bacterial populations, as high as 105 (colony forming units) CFU g-1 soil, tolerant of 500 mg L-1 Cr(VI) were isolated from all soils within 48 h of enrichment suggesting that the presence of aerobic Cr(VI)-resistant bacterial populations is unrelated to contamination levels or contamination history. However, identification of these resistant bacteria using fatty acid profiles was unsuccessful suggesting that these populations may have unique characteristics. Fungal colonies resistant to 1000 mg L-1 Cr(VI) were routinely isolated from both uncontaminated and contaminated soils. The results suggest that Cr-resistant microorganisms may be present in soils, even those with no history of Cr contamination.