bluuebunny/crossref_metadata_2025 huggingface dataset:
Detoxification and reclamation of Suncor's oil sand tailings ponds
Authors: Nix P. G. , Martin R. W.
Published: October 2006

Suncor, Inc., operates an oil sands mining and extraction plant in northern Alberta, and uses tailings ponds for disposal of waste tailings sludge and for conditioning recycle water. In their active state, tailings ponds consist of a layer of toxic top water overlying a viscous layer of sludge containing toxic interstitial water as well as particles of unprocessed bitumen and clay fines. To address the need for reclamation of the mine site, Suncor is exploring a concept of sludge disposal whereby mature sludge would be pumped out of existing tailings ponds into a mined pit area with an overlying layer of top water. This reclamation strategy would retain both top water and sludge on site in contrast to conventional schemes whereby sludge would be dewatered and reclaimed using dry land reclamation techniques (i.e., revegetation). The success of this wet pond reclamation scheme would rely on natural processes of microbial biodegradation and detoxification over time to achieve improvements in the quality of the top water layer. Although anaerobic interstitial water in the sludge may remain toxic for long periods, the sludge would be permanently isolated beneath a surface layer of top water.

Bench‐scale and field‐scale tests (e.g., test tanks and large pits) were utilized in a series of experiments to assess the feasibility of wet pond reclamation. Toxicological testing of the top water layer characterized the rate of detoxification, and elucidated the nature and extent of subsequent colonization by aquatic plants and animals. The results suggest that after mine abandonment, a reclaimed tailings pond could be designed such that it is transformed over time from a toxic waste pond into a viable and productive ecosystem with biologically complex aquatic communities in its surface water.
Glyphosate effects on microbial biomass in a coniferous forest soil
Authors: Stratton Glenn W. , Stewart K. Elaine
Published: October 2006

The herbicide glyphosate (Roundup) was applied aerially to a conifer forest that had previously been clear‐cut and reforested. Glyphosate was tested for effects on microbial biomass, numbers of selected microorganisms, and soil respiration over a period of 8 months by comparing treated and untreated zones of the clay loam forest soil (FS) and the overlying litter (FL), both pH 3.8. With microbial biomass, glyphosate generally had a stimulatory effect in FL, but usually no significant effect in FS. Glyphosate had no significant effect on numbers of bacteria, fungi, and actinomycetes in either FL or FS. The herbicide generally stimulated respiration in both FL and FS. In laboratory bioassays using FL, FS, and three agricultural soils, glyphosate had no significant effect on respiration when used at concentrations up to 100 times higher than recommended field application rates. Respiration rates in FL, as measured with Warburg respirometry, were unaffected by glyphosate. Respiration rates in FS were stimulated by glyphosate concentrations 10 and 100 times higher than recommended field rates. Glyphosate should have no deleterious effects on microbial biomass and respiration in forest soils when used under recommended conditions. © 1992 John Wiley & sons, Inc.
Cadmium biosorption and toxicity to six cadmium‐resistant gram‐positive bacteria isolated from contaminated soil
Authors: Boularbah Ali , Morel J. L. , Bitton G. , Guckert A.
Published: October 2006

Six Cd‐resistant bacterial strains were isolated from a soil receiving dredged sediments and containing Cd at concentration of 50 mg kg−1. The isolates, identified as gram‐positive, were studied with regard to their ability to tolerate and accumulate Cd at concentrations varying from 0 to 100 mg L−1. Results showed an increase in accumulated Cd in bacteria with increasing Cd concentrations in solution. Isolates were shown to tolerate higher Cd concentrations than a Bacillus subtilis strain used as a control. One of the isolates, identified as Bacillus brevis, was found to be the most resistant to Cd, with an ability to accumulate the toxic metal up to 70 mg−1 of cells (dry weight). Mn was found to reduce Cd toxicity and accumulation in B. brevis. This strain may have some potential interest in reclamation of metal‐contaminated soils. © 1992 John Wiley & sons, Inc.
Multiple assays of uranium toxicity in soil
Authors: Sheppard S. C. , Evenden W. G. , Anderson A. J.
Published: October 2006

The literature offers conflicting information on the phytotoxicity of uranium (U) in soil. Levels as low as 5 mg U/kg soil, well within the normal background range, have been cited as toxic, whereas many studies report no toxicity at levels 100‐ to 1000‐fold higher. Uranium in soil does not often present a radiological hazard to humans, but toxicity to plants could lead to prescribed cleanup and assessment criteria for industrial activities. This study was designed to identify the toxic threshold of soil U. Nine levels of U were added to background‐level soils. Beans were grown to maturity in an outdoor lysimeter study with 2 soils. Germination tests in the growth chamber were done with 11 soils and with 5 plant species. A rapid cyclingBrassica rapacultivar, proposed as a new toxicity test subject, was grown to maturity on 2 soils in the growth chamber, and germination of the second‐generation seeds was investigated. Earthworm survival and soil phosphatase activity were measured. Measures of soil‐extractable and tissue U concentrations were obtained. None of the measurements indicated detrimental effects of U below 300 mg/kg. In one of the soils,B. rapaproduced seed at concentrations as high as 10,000 mg U/kg. The phytotoxicity of U occurred at concentrations 8‐ and 3‐fold higher than the concentrations of As and Zn, respectively, which gave the same effect. © 1992 John Wiley & sons, Inc.
Sulfate elimination to improve water quality of mine process effluents. I. Sequencing batch bioreactor growth kinetics of desulfovibrio desulfuricans
Authors: Herrera Leandro , Duarte Sergio , Hernandez Jose
Published: October 2006

The sulfate reducing bacterium, Desulfovibrio desulfuricans NCIMB 8372, was cultured in a 1‐L biochemical reactor. The reactor was operated in a sequential batch mode and the results of four sequential runs are presented (the first run was a recently inoculated reactor).

Results fall within the range of published results, reaching sulfate reduction rates up to 2764.8 mg/L/day. The bacteria attached to the reactor walls and a method was proposed to evaluate the magnitude of the adhered cells fraction, which resulted in a value of 1.2–3.0 · 106 cells/cm2, a value that correlated well with cells counted in scanning microscope photographs taken from a tube in the reactor. © 1993 John Wiley and Sons.
Ecotoxicity testing of heavy metals using methods of sediment microbiology
Authors: Reichardt W. , Heise S. , Piker L.
Published: October 2006

Current measures of microbe‐mediated biogeochemical processes in sediments were examined for their potential use as indicators of heavy metal ecotoxicity in both river sediments and bacterial cultures. Assays were carried out with HgCl2, CuSO4, and 3CdSO4 · 8H2O added to sediment samples and bacterial cell suspensions at concentrations ranging from 0.1 to 10 mM and 0.1 μM to 1 mM, respectively.

Chemoautotrophic CO2 fixation by Elbe River sediment microbiota was most sensitive to Hg2+ and Cd2+, but not to Cu2+.

Among the estimates of heterotrophic productivity, incorporation of leucine into cellular protein showed clearer dose responses than incorporation of thymidine into bacterial DNA. Thymidine incorporation was highly resistant to and even stimulated by metal ions, particularly in starved and anaerobic cultures of a test strain of Vibrio anguillarum. Similar metal ion induced “overshoot” responses beyond the levels of untreated controls were noted for mineralization of 14C‐glucose by V. anguillarum and, in the case of Cd2+, also in sediment.

As a less complex measure of microbial respiratory activity, succinate dehydrogenase (SDH) showed normal dose responses without stimulatory effects, as long as bacterial cell homogenates were assayed. Despite this result, it is concluded that levels of SDH in natural sediment microbiota are inevitably affected by metal‐induced processes of selection and enzyme synthesis, and would thus fail to provide an appropriate measure of metal ecotoxicity. The final conclusion is that current parameters of microbial production and activity often reveal dose responses that do not fulfill basic requirements of ecotoxicity testing in metal‐polluted sediments. © 1993 John Wiley & Sons, Inc.
Monitoring sãto paulo state rivers in brazil for mutagenic activity using the ames test
Authors: Valent Gisela U. , Sato Maria Ines Z. , Cristina Maria , Coelho L. S. , Coimbrão Carlos Alberto , Sanchez Petra S. , Martins Maria Therezinha , Bonatelli Renato
Published: October 2006

Organic extracts of raw water from 11 water courses of São Paulo State, Brazil, were collected during one year bimonthly and tested for mutagenicity using the Ames test, with strains TA98 and TA100 of Salmonella typhimurium with and without metabolic activation. The samples were extracted with XAD2 resin and eluted with methanol and methylene chloride. From the 75 samples analyzed, 14 showed positive responses and 8 were considered marginal, making up 29% of mutagenic samples. The percentage of mutagenic samples in October (spring) was 9%, increasing to 64% in February (summer), and decreased to 9% again in August (winter). Paraiba do Sul river showed the higher percentage of mutagenic samples (67%) and Capivari river the highest mutagenic sample (1787 and 3265 revertants per liter for TA98 without and with S9, respectively).

The amplitude of the mutagenic response was 39–3265 revertants per liter for TA98 and 83–467 for TA100. The mutagenic samples showed direct and indirect mutagens, and TA98 detected the majority of responses, indicating prevalence of frameshift mutagens in these samples. © 1993 John Wiley & Sons, Inc.
Potential application of biophysical interrelationships for faster evaluation of sequencing batch reactor effluent quality
Authors: Sim T. S. , Ng W. J. , Ong S. L. , Ng K. Y. , Ramasamy M. , Tan K. N.
Published: October 2006

Conventional parameters for assessing effluent quality like the 5‐day biological oxygen demand, (BOD5), total suspended solids (TSS), and coliforms take from one to five days before the tests are completed. Simple, rapid, economical, and reliable methods to determine wastewater quality parameters are essential for the effective control of effluent discharges and the monitoring of process performance. If disinfection is necessary, these rapid methods may be used to quickly estimate the disinfection requirements and to ensure that the final effluent quality is microbiologically adequate. This is especially applicable to the sequencing batch reactor system, which treats wastewater in a batchwise manner. The 6‐h coliphage, 3‐h chemical oxygen demand (COD) and 1/2‐h total organic carbon (TOC) tests have been identified as rapid tests. Being microbiologically related, the coliphage test was shown to have a good degree of correlation with coliform levels in the effluent. Predictions of coliform numbers may be made by enumeration of the phages. The COD was also correlated and shown to produce a quick estimate of the total BOD5, TSS, and coliform values. Although the TOC test is based on the dissolved portion of the effluent, it may also be used as a rapid estimation of the total BOD5, TSS, and coliform values. © 1994 by John Wiley & Sons, Inc..
Microbial toxicity mechanism of copper‐8‐quinolinolate
Authors: Liu D. , Maguire R. J. , Pacepavlcius G. J. , Carey J.
Published: October 2006

Sapstain, an abnormal discoloration in wood caused by microbial growth, can significantly lower the price of a lumber and thus fresh sawn softwood lumber of a susceptible species is often treated with a biocide such as pentachlorophenol (PCP) to prevent the development of sapstain during shipping and prolonged storage. Very recently, chlorophenol‐based antisapstain agents have been banned in Canada, because of environmental toxicity. The purpose of this study was to elucidate the microbial toxicity mechanism of the copper salts of 8‐quinolinolate (Cu‐8‐HQ), one of the replacement chemicals for PCP in sapstain control. The results revealed that the biocidal activity of Cu‐8‐HQ originates from a stable metal (copper) chelate and that the molecular integrity of the chelate is most critical in the expression of its toxicity potential. The chelating power of 8‐hydroxyquinoline for trace metals was not found to be directly responsible for the biocidal activity of Cu‐8‐HQ as suggested in the literature. The anion groups were found to have no significant impact on the biocidal activity of Cu‐8‐HQ, which has been observed with other organometallic compounds. © 1994 by John Wiley & Sons, Inc..
Distribution of dichlorodiphenyltrichloroethane (DDT) and its metabolites in an Indian waterway
Authors: Sujatha C. H. , Nair S. M. , Kumar N. C. , Chacko J.
Published: October 2006

This paper reports on the results of systematic analyses carried out to assess the distribution of dichlorodiphenyltrichloroethane (DDT) and its metabolites, o,p′‐DDT, p,p′‐DDE, and p,p′‐DDD in a tropical waterway, the Cochin Estuarine System. Six sampling stations along the system were studied. Analyses were carried out during premonsoon, monsoon, and postmonsoon seasons. ΣDDT concentrations as high as 55.422 μg L−1 were detected. The predominant DDT metabolite was found to be p,p′‐DDE. During the monsoon season, o,p′‐DDT was not detected at any of the sampling Stations. Station 1 (riverine) and station 6 (coastal zone barmouth) emerged as DDT‐free zones and the analytical results have enabled the identification of DDT “hot spots” in the estuary. © 1994 by John Wiley & Sons, Inc..
Removal of influenza A virus, phage T1, and PP7 from fluids with a nylon 0.04‐μM membrane filter
Authors: Oshima Kevin H. , Highsmith Anita K. , Ades Edwin W.
Published: October 2006

We tested the ability of a 0.04‐μm nylon membrane filter to remove viral agents (influenza A virus, 80–120 nm; phage T1, 50–150 nm; and phage PP7, 25 nm) from the following media: ultrapure water (UPW), Dulbecco's modified Eagle minimum essential medium (DMEM), gelatin phosphate (GP), DMEM with 10% (DMEM‐10) fetal bovine serum (FBS), and 100% FBS. When challenged with at least 3.0 × 107 plaque‐forming units/mL, no influenza A virus was detected downstream of the filter with any of the fluids tested. The titer reduction (Tr) was determined using the equation:

equation image
.

Higher concentrations of phage T1 were removed from UPW (Tr = 1.6 × 106) and DMEM (Tr = 1.1 × 106) than from GP (Tr = 9.3 × 103), DMEM‐10 (Tr = 1.5 × 102), and 100% FBS (Tr = 2.4 × 102). Phage PP7 was removed in significant numbers only in ultrapure water (Tr = 8.5 × 104). The results indicate that adsorption enhanced the titer reduction in fluids containing low levels of protein. The titer reduction in DMEM‐10 and 100% FBS may reflect the sieving properties of the 0.04‐μm filter. As expected, a much smaller Tr was observed in the filtrate of the 0.2‐μm filters, compared to the 0.04 μm filters. In contrast to the 0.04‐μm filter, no increase in Tr was detected when the 0.2‐μm filters were challenged with virus diluted in UPW compared with virus diluted in GP. These results suggest that the 0.04‐μm filter has greater adsorptive properties than the 0.2‐μm filter. © 1994 by John Wiley & Sons, Inc..
The effects of chromium on the growth and activity of a pentachlorophenol‐degrading bacterium
Authors: Wall A. James , Stratton Glenn W.
Published: October 2006

The effects of chromium (or chromate, as supplied by CrO3) on a pentachlorophenol‐degrading Flavobacterium sp. (ATCC 53874) were examined in a liquid bacterial growth medium. Cr6+ concentrations ⩾ 5.0 μg mL−1 caused the complete inhibition of bacterial growth. The EC25, EC50, and EC75 calculated after 96 h of incubation were 0.44, 1.44, and 3.82 μg mL−1, respectively. Cr6+ caused an irreversible reduction in total cell yield during the 21‐day incubation. Cr6+ also elicited an increase in the lag time recorded before there was measurable pentachlorophenol (PCP) degradation by this bacterium. There was also an increase in the overall time required for complete degradation of PCP to nondetectable levels. A similar response was noted with all PCP concentrations examined from 10 to 100 μg mL−1. However, a more pronounced response occurred at the lower PCP concentrations. The significance of these data relative to the in situ use of PCP‐degrading bacteria for site bioremediation is outlined. © 1994 by John Wiley & Sons, Inc..
Toxicity and genotoxicity enhancement during polycyclic aromatic hydrocarbons' biodegradation
Authors: Belkin Shimshon , Stieber Michael , Tiehm Andreas , Frimmel F. H. , Abeliovich Aharon , Werner Peter , Ulitzur Shimon
Published: October 2006

Several laboratory column percolators were operated in order to study the bioremediation potential of polycyclic aromatic hydrocarbons (PAH)‐contaminated soils. The columns contained either soil artificially amended with specific PAH mixtures or contaminated soil from a site in Karlsruhe, Germany. In all cases, biodegradative processes led to the elimination of the original contaminants. This, however, was accompanied by a marked increase in genotoxic activity of the column effluents as determined by the MutatoxTM assay. Genotoxicity was practically abolished, however, when a surfactant was added to the percolating fluids. While in some cases the changes in genotoxicity were paralleled by toxicity (MicrotoxTM) data, in others the trend was opposite.

It is concluded that when degradation is incomplete, the potential exists for toxicity and genotoxicity enhancement, with the latter hazard not always predictable by short‐term toxicity assays. Routine genotoxicity monitoring is thus advocated for bioremediation projects; the MutatoxTM assay appears to be a convenient tool for this purpose. © 1994 by John Wiley & Sons, Inc..
Utilization of a bioluminescence toxicity assay for optimal design of biological and physicochemical wastewater treatment processes
Authors: Brenner Asher , Belkin Shimshon , Ulitzur Shimon , Abeliovich Aharon
Published: October 2006

A comprehensive laboratory investigation was conducted to test the feasibility of employing biological and physicochemical treatment processes for complex wastewaters discharged by several chemical industries. Results obtained during this study indicated that the wastes contain a fraction of toxic and nonbiodegradable organic matter, which limits the implementation of a conventional biological treatment process for the combined wastewater stream.

Toxicity, as measured by a bioluminescence assay (Microtox), served as a valuable tool to assess biological treatability of various waste sources, with the aim to select an economically feasible and environmentally acceptable treatment/management program for an industrial park. Toxicity values served as quantitative indices for the establishment of baseline data of removability potential, defined either by biodegradation or carbon adsorption. This removability data enabled identification of problematic waste sources, which are only partially biodegradable and/or possess considerable toxicity.

Further investigation of the problematic waste streams focused on the evaluation of activated carbon adsorption characteristics, using toxicity balances instead of traditional chemical determinations. This method could be successfully employed to yield simultaneously both adsorption characteristics and an assessment of the impact of the treated effluent on biota in receiving waters. © 1994 by John Wiley & Sons, Inc..
Bioassessment of water quality
Authors: Wong P. T. S. , Dixon D. G.
Published: October 2006

Over the past 20 years there has been a concerted effort to define and limit the impacts of anthropogenic contaminants in aquatic environments. There are essentially two philosophies that can be employed to regulate and to assess the effects of toxic chemicals in these systems. The first is the water quality objectives research. Under this protocol, laboratory research is used to set an objective, the concentration of a substance or condition that is considered to have no effect on the organisms in an aquatic environment based on a review of the pertinent research. The second approach, environmental health assessment, uses the in situ responses of free‐living organisms in contaminated environments to determine the overall impacts of the environment on those organisms. In this review paper we will attempt to compare and contrast the advantages and disadvantages of the two approaches, and to outline a system whereby they can be used together to enhance our degree of confidence in legislation directed at reducing contaminant impacts. ©by John Wiley & Sons, Inc.
A review of the aquatic ecotoxicology of polychlorinated dibenzo‐p‐dioxins and dibenzofurans
Authors: Grimwood Mark J. , Dobbs Tony J.
Published: October 2006

This paper reviews published studies on polychlorinated dibenzo‐p‐dioxins and polychlorinated dibenzofurans that are relevant to an assessment of their aquatic ecotoxicology. The available data suggest that laterally substituted congeners containing altogether 4,5, or 6 chlorine atoms are highly toxic, particularly to the early life stages of fish, with reported effect concentrations in the ng L1 range. These congeners are also the most readily bioaccumulated.

An aquatic toxicity threshold concentration of 0.011–0.038 ng L−1, applicable to natural ecosystems, was determined for 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (or for mixtures of congeners expressed as 2,3,7,8‐TCDD equivalents). This threshold corresponds to the no observed effect concentration/lowest‐observed effect concentration determined for mortality, growth, and behavioral effects seen in rainbow trout early life stages, exposed to 2,3,7,8‐TCDD in a flow‐through system over a 28‐day period, followed by 28 days of depuration.

An investigation was also made into the potential for using mammalian‐derived toxic equivalency factors (TEFs) in aquatic ecosystems. This revealed that such an approach may underestimate the aquatic toxicity of some congeners, and that the use of organism‐specific TEFs may be more appropriate. © by John Wiley & Sons, Inc.
Bioassay assessment of impacts of tar sands extraction operations
Authors: Dutka B. J. , Bourbonniere R. , McInnis R. , Kwan K. K. , Jurkovic A.
Published: October 2006

This report describes the application of ten bioassays (battery of tests approach) to waters and sediments collected from the tar sands area of northern Alberta, Canada. In this study there were three main goals: (1) to establish the presence and sources of toxicants in these northern waters and sediments, (2) to determine if their presence is related to sediment composition, and (3) to establish which of the various sediment extracting procedures used was most efficient in producing responses in the bioassays used.

Results of these investigations indicated that there were two obvious sources of toxicants/genotoxicants, the tar sands extracting area and streams passing through tar sands or oil shales and at least two unknown sources. Based on the techniques used in this study, there does not appear to be a strong sediment structure–toxicant response relationship. Extraction procedure results were variable and are discussed in detail in the report. © by John Wiley & Sons, Inc.
Biodegradation of the herbicides 2,4‐dichlorophenoxyacetic acid, 2,4,5‐trichlorophenoxyacetic acid, and 2‐methyl‐4‐chlorophenoxyacetic acid in a sulfate‐reducing aquifer
Authors: Kuhlmann Birgit , Kaczmarzcyk Barbara
Published: October 2006

Biodegradation of trace organic compounds is one of the main mechanisms to purify infiltrating surface water during bankfiltration and underground passage. In anaerobic zones of the underground, rate and extent of degrading processes may be totally different from those in aerobic ones. To investigate this, a model ecosystem was built that reproduces an anaerobic part of the aquifer and the behavior of the three phenoxyacetic acid herbicides 2,4‐dichlorophenoxyacetic acid, (2,4‐D), 2,4,5‐trichlorophenoxyacetic acid (2,4,5‐T), and 2‐Methyl‐4‐chlorophenoxyacetic acid (MCPA) tested. In anaerobic experiments with varying conditions they proved to be almost persistent. Only under aerobic conditions could biodegradation be observed after a lag period. © by John Wiley & Sons, Inc.
Ecotoxicological evaluation of contaminated soil using the legume root nodule symbiosis as effect parameter
Authors: Wetzel Astrid , Werner Dietrich
Published: October 2006

The legume root nodules are the site of biological nitrogen fixation in the legume—rhizobium symbiosis. They are a structure unique to this symbiosis and morphologically as well as physiologically distinct from other plant organs. We will present evidence that the formation of nodules (nodulation) may serve for ecotoxicological evaluation of contaminated soil. Substances affecting the macro‐ and/or microsymbionts vitality, such as certain heavy metals or polycyclic aromatic hydrocarbons (PAHs), reduce nodulation before visible damage of the plant occurs. Tests were performed in petri dishes that were planted with alfalfa seedlings and inoculated with Rhizobium meliloti. Mineral agar served as substrate. Test substances were added to the mineral agar before pouring it into petri dishes (application of heavy metals), or were sprayed as etheral solutions onto the surface of solidified medium (application of PAHs). For investigation of contaminated soil, the soil material was first mixed with mineral agar and then poured into petri dishes. Appropriate controls were made by extracting an aliquot of soil with methylene chloride to remove hazardous substances. Data from stressed plants were taken after 15 days of cultivation on contaminated substrate. A dose‐responsive decrease in nodulation was found after application of CdCl2, NaAsO2, fluoranthene, and other PAHs. PAH‐contaminated soil (75 mg/kg) caused only a slight reduction in nodulation of alfalfa. But when PAHs were extracted and restored into the extracted soil material, toxicity and uptake of PAHs into roots and shoots dramatically increased. Toxicity and uptake of PAHs were also enhanced by reducing the amount of humic matter added to the test system. © by John Wiley & Sons, Inc.
Precautions for routine use of INT‐reductase activity for measuring biological activities in soil and sediments
Authors: Merlin G. , Lissolo T. , Morel V. , Rossel D. , Tarradellas J.
Published: October 2006

To evaluate toxicity of xenobiotics on microflora of soils and sediments, reduction of tetrazolium dye [2‐p‐iodophenyl‐3‐p‐nitrophenyl‐5‐phenyltetrazolium chloride (INT) or 2,3,5 triphenyltetrazolium chloride (TTC)] by dehydrogenase activities is commonly used, but many questions are posed about the biological relevance of this test.

In this work, INT was chosen to evaluate the influence of some experimental factors on reductase activity. INT adsorption to soil, concentration of INT, and sterilization methods were tested on different soils and sediments to determine bioavailability of INT, saturation concentration, and intensity of chemical reduction.

INT adsorption shown dramatic variations vs type of soil, from 0 to 100%, and was particularly linked with cation exchange capacity.

Formaldehyde seems to be the best method with irradiation to determine abiotic reduction, particularly with sediments.

However, it must be stressed that the tetrazolium reduction in microbial systems can be carried out by other enzymatic systems than malate dehydrogenase. INT is an excellent substrate of membrane hydrogenases found in numerous anaerobic bacteria. This was observed with experiments conducted with Rhodobacter capsulatus in our laboratory. © by John Wiley & Sons, Inc.
Direct sediment toxicity testing procedure using sediment‐chromotest kit
Authors: Kwan K. K.
Published: October 2006

A semiquantitative direct sediment toxicity testing procedure using the Sediment‐Chromotest was developed. This procedure has advantages over many other toxicity bioassays. It is simple, quick, and reliable, and does not require special instrumentation.

The direct sediment toxicity testing procedure involves the use of serial dilutions of solid phase suspensions mixed with stressed bacteria (Escherichia coli) and a cocktail containing the specific inducer for the chromogenic enzyme and other essential factors. The assay is based on the ability of toxicants to inhibit the de novo synthesis of an inducible enzyme, beta‐galactosidase. The amount of de novo synthesized enzyme is determined by a colorimetric reaction.

This new procedure measures the presence of bioavailable toxicants in sediments, suspended sediments, soils, and other solid wastes directly without extraction and concentration. © by John Wiley & Sons, Inc.
Testing of chlorinated solvents on microfungi
Authors: Steiman R. , Seigle‐Murandi F. , Guiraud P. , Benoit‐Guyod J.‐L.
Published: October 2006

In order to avoid the use of a sophisticated method for the determination of 3 volatile solvents (dichloromethane, tetrachloroethylene, and perchloroethylene) in the atmosphere, an alternative method was tentatively developed for the evaluation of their toxicity toward micromycetes isolated from the biological communities present in the sediments of aquatic microcosms. Survival of the microorganisms was determined by establishing the minimum lethal time50 at saturation in a vessel saturated with vapors. The method allows one to look for the development of an induction or a sensitization and can be used for any other volatile xenobiotic. © by John Wiley & Sons, Inc.
Genotoxicity of some wastewaters in India
Authors: Malik Abdul , Ahmad Masood
Published: October 2006

Heavy metal concentrations in wastewaters from the industrial estate of Aligarh city (U.P.) India were determined. The analysis of test samples revealed significantly higher levels of Fe, Zn, Cu, Cr, and Ni compared with the pure domestic samples. Raw wastewaters were screened for mutagenic potential using the Ames Salmonella/microsomal test. Mutagenic activity was observed with industrial as well as domestic waste samples. Salmonella typhimurium strains TA102 and TA104 were the most sensitive both in the absence and presence of S9 fraction. A significant decrease in the survival of DNA repair defective Escherichia coli mutants recA, lex A, and polA was observed as compared to their wild‐type counterparts in the presence of wastewater. © by John Wiley & Sons, Inc.
A test battery of bacterial toxicity assays and comparison with LD50 values
Authors: Lenz P. , Süssmuth R. , Seibel E.
Published: October 2006

The toxicity of some mycotoxins, lactones and dicarboxylic anhydrides, insecticides, herbicides, and fungicides can be detected by means of bacterial assays. In addition, the order of magnitude of the toxicity can also be evaluated.

Fifty‐eight chemicals as well as extracts of peanuts, apple juices, and grains have been investigated in a test battery of three different kinds of assays. In cup plate diffusion assays a minimal amount of approximately 0. 1 mg/mL of mycotoxin may be detected by means of growth inhibition assays with Bacillus thuringiensis on one hand, and pigment synthesis inhibition assays with mutants of Serratia marcescens on the other hand. Swarming inhibition assays with the motile strains Azospirillum brasilense and Proteus mirabilis show the same sensitivity. Comparisons of our test battery with other bioassays, as well as with mammalian toxicity tests (LD50 values), reveal correlations between these kinds of assays in regard to the test substances.
Biodegradation of pentachlorophenol and its commercial formulation
Authors: Liu D.
Published: October 2006

Biodegradation processes for pentachlorophenol (PCP) and a commercial PCP formulation were evaluated to delineate factors limiting the rate of PCP degradation in the aquatic environment. Analyses of the data on PCP disappearance and chloride ion release, as well as gas chromatography and UV‐VIS (ultra‐violet and visible spectroscopy) spectra of the fermentor broth strongly indicate that the bacterial culture acted on PCP by completely stripping off all the chloride ions from a molecule of PCP, rather than following the normal pattern of removing only one chloride ion at a time. The haloaromatic ring structure of PCP was completely broken down, and not channeled into the unproductive meta‐cleavage pathway. Despite repeated transfers of the bacterial culture, an initial lag phase in PCP biodegradation was apparent in all experiments and was followed by a steady state, nearly linear rate of PCP degradation. Thus in the aquatic environment the biodegradation rate of a persistent contaminant is more likely to be regulated by whether or not this compartment has been previously subjected to a long or continuous exposure to a particular chemical. First‐order kinetics alone cannot be used to predict accurately the fate of a persistent chemical in the environment, because of the inability of such a simple equation to accommodate the effects of rate‐limiting factors such as the length of adaptation period on the overall biodegradation rate of a contaminant. For this reason, factors that may influence a chemical's biodegradability in the natural environment must be considered in the design of laboratory biodegradation experiments.
Effects on human health of some toxic cyanobacteria (blue‐green algae) in reservoirs, lakes, and rivers
Authors: Falconer Ian R.
Published: October 2006

The public water supply has been implicated in gastrointestinal disorders in the United States, East Africa, and Australia, associated with the lysis of heavy blooms of cyanobacteria. The causative organisms include Microcystis, Anabaena, Aphanizomenon, and Oscillatoria. Using epidemiological techniques, we have shown significant increase in liver enzymes in blood, particularly γ‐glutamyl transpeptidase, during a toxic bloom in the reservoir of a city. Therefore, public health awareness of the risks, and consequent action to control water blooms and remove harmful compounds from drinking water supplies, is required.
Use of protozoan communities to assess the ecotoxicological hazard of contaminated sediments
Authors: Henebry Michael S. , Ross Philippe E.
Published: October 2006

Protozoan communities developed on artificial substrates were used in a series of in situ and laboratory tests to evaluate the toxic potential of harbor sediments contaminated with polychlorinated biphenyl (PCB). Colonization dynamics in polluted and clean harbors were compared. Laboratory tests were community bioassays using standard techniques to produce sediment elutriate. Results of the in situ colonization and the community tests measuring structural changes (e.g., “decolonization”) were similar. In general, sediments from the contaminated harbor caused significant (p ⩽ 0.05) reductions in the number of taxa, in total protozoan abundance, and in phototroph abundance; however, the abundance of heterotrophic species increased in some in situ tests. Process‐level parameters (e.g., respiration; island‐epicenter colonization rates) were more sensitive than measurements of community structure. Phototrophs were more sensitive to sediment elutriate than were other trophic types. The information provided by this series of protozoan community tests is more complex than that provided by single‐species bioassays. Although community tests may provide more information on the effects of sediment contamination on actual ecosystems than tests based on single species, they require careful interpretation to avoid misleading conclusions.
Microbiology of potable water in Canada: An overview of the health and welfare Canada program
Authors: Tobin Richard S.
Published: October 2006

Responsibility for drinking water quality in Canada is primarily a provincial obligation, but the Department of National Health and Welfare (NHW) plays an important role in the establishment of national guidelines, conducting research on problems of national concern, and providing advice on point‐of‐use devices. The microbiological quality of drinking water is regarded as one of the most important parameters in view of the low but continuing reports of waterborne disease. During the period from 1974 to 1982, there were 42 reported outbreaks involving 1789 persons. The known causative agents were bacteria, Giardia, and viruses.

The microbiology program of NHW includes development of the microbiological parameters in the Guidelines for Canadian Drinking Water Quality, collecting and disseminating the data on waterborne disease in Canada, sponsoring and collaborating in research studies on the microbiological hazards in drinking water, participating in the investigation of local and regional water problems, testing and evaluation of point‐of‐use water treatment devices, and providing educational material for the public and the media. Each of these aspects is described in this paper. Particular emphasis is placed on the waterborne illness in the last decade and some of the results of the studies on Giardia removal or inactivation in potable water.
Bacteriological aspects of a mountain watershed
Authors: Adams J. C. , Skinner Q. D.
Published: October 2006

Numbers of fecal coliforms and fecal streptococci increased during the winter in a stream near a ski area. These numbers returned to background levels within a month after the ski area closed for the year. As the pollution events continued with time, the day of the week on which maximal numbers were obtained changed. Maximum numbers of these bacteria were seen in the afternoons when pollution was occurring. Minimum numbers were found in the morning.

Fecal coliforms and fecal streptococci were enumerated in a stream above and below the ski area for three summers. Statistically significant differences in the numbers of these organisms occurred between the months studied, depending upon whether the statistics were run upon numbers per 100 mL or upon numbers passing a point per second.
Utilization and water quality management of lake kinneret, Israel
Authors: Gophen M.
Published: October 2006

Kinneret, the only natural freshwater lake in Israel, is used as the major source for drinking water and is also utilized for commercial fishing, recreation, and tourism. Recreational pressure was averaged as 190 IKD [Individuals/km (53 km shoreline)/day] during May–September. Total population in the drainage basin (2730 km2) is approximated as 255 × 103. Before 1980, most of the domestic sewage (18000 m3/day) and fish‐pond wastes drained into the lake. The major sources of intestinal and pathogenic bacteria found in lake water were untreated domestic sewage, cows in pasture lands through water runoff, and directly from the recreational population. Partial implementation of a master plan for sewage removal has led to the diversion of about 60% of the sewage into reservoirs constructed in the drainage basin for irrigation reuse. Consequently, the presence of intestinal bacteria in Jordan inlet (the major drainage river) declined. Sewage removal systems were also constructed along all the shoreline. Reduction of intestinal bacteria densities in public beach waters was also recorded. On the other hand, nutrients (mostly P) and phytoplankton (density and composition) in the lake slightly deteriorated water quality. The management design is dependent on water quality standards. In the case of a higher quality standard, lake utilization for drinking requires a thorough treatment and water consumption for irrigation is more efficient.
Factors affecting the magnitude of toxicant interactions in microbial bioassays
Authors: Stratton Glenn W.
Published: October 2006

A toxicant interaction method was used to study the effects of various bioassay parameters on interaction responses obtained in microbial bioassays. The fungus Pythium ultimum was employed as the test organism, and was exposed to various combinations of the fungicide captan and several organic solvents, using a poisoned agar technique. In all cases the fungicide and solvents interacted synergistically toward culture growth. For most experiments acetone was used as the test solvent. Where pH and temperature were altered, the magnitude of the interaction response between captan and acetone increased dramatically as the pH or temperature was raised from 4.5 to 7.5, or 15 to 30°C, respectively. This corresponded to similar increases in the culture growth rate and decreases in the toxicity of captan. When the medium composition was changed, interaction magnitudes were again greatest in media eliciting the fastest growth rate. These media also yielded the lowest captan toxicity. The largest interaction magnitudes occurred with V8 juice agar, followed by corn meal agar, potato dextrose agar, and malt extract agar. When the solvent used in the interaction experiments was changed, a similar response was obtained, in that the greatest interaction magnitudes occurred in systems eliciting the lowest captan toxicity. The largest magnitudes were measured with acetone, followed by hexane, ethanol, dimethylformamide, methanol, and dimethyl sulfoxide. The significance of these data in toxicant interaction bioassays is discussed.
Assessment of the interaction between microorganism and chemical mixture using resazurin reduction
Authors: Liu D.
Published: October 2006

The interaction between microorganism and chemical mixture was studied using resazurin reduction to delineate the microbial response to toxic substances. Two chemical mixtures, one consisting of two similar chemicals (2,3‐dichlorophenol and pentachlorophenol) and another of two dissimilar compounds (mercuric chloride and 2,3‐dichlorophenol), were tested on three pure bacterial isolates. Various toxicity patterns encompassing synergistic, neutral, and antagonistic effects on test bacteria were observed, demonstrating that the observed toxicity response from a chemical mixture does not always match the summed toxicity responses of the chemicals tested individually. No overall pattern regarding the interaction between microorganism and chemical mixture's toxicity could be drawn, implying that the traditional philosophy of setting water quality standards based on the toxicity assessment of individual chemicals should be readdressed to reflect the complexity of managing toxic substances in the aquatic environment.
Heptapeptide toxins contained in natural samples of Microcystis species
Authors: Watanabe Mariyo F. , Harada Kenichi , Matsuura Kenji , Oishi Shinshi , Watanabe Yasunori , Suzuki Makoto
Published: October 2006

Toxins contained in Microcystis species were examined for natural samples of water bloom collected from several lakes in Japan. The toxins were identified as microcystins (cyanoginosins)‐LR,‐YR, and ‐RR. The amounts of the three toxins were estimated after adsorption to a C18 cartridge, eluted with methanol, and subjected to high performance liquid chromatography using an octa decylsilanized column. Microcystins‐RR and ‐LR were the main components of the toxins contained in natural samples of Microcystis bloom, while YR was not detected in more than half of the samples analyzed. Six samples were also examined in relation to LD50 values and species composition of Microcystis. The highest total amount of the three toxins was obtained for the sample with the lowest LD50 value and composed mostly of cells of M. aeruginosa. The relation between LD50 values and total contents of the three toxins was well fitted to the formula Y = 1100 × X−1.079, where Y is the LD50 value and X is the total amount of the three toxins.
Effects of heavy metals on the biology of a N2‐fixing cyanobacterium Anabaena doliolum
Authors: Mallick Nirupama , Rai L. C.
Published: October 2006

The effects of copper, nickel, and iron on survival, growth, nutrient uptake (NH, NO, and PO), carbon fixation, nitrate reductase, nitrogenase (CH2 reduction assay), glutamine synthetase (transferase), and alkaline phophatase activities of Anabaena doliolum were studied. About 50% survival of the test alga was scored at 8.0 × 10−3, 8.6 × 10−3, and 0.36 mM of Cu, Ni, and Fe, respectively. However 45, 59, and 57% reductions in final yield were scored, respectively, at LD50 concentrations of Cu, Ni, and Fe. On the basis of the LD50 of the test metals, Ni was the most inhibitory for nutrient uptake. However, the LD50 concentrations of Cu, Ni, and Fe showed different levels of inhibition for different processes. Although metal concentrations higher than LD50 were found to be more inhibitory, 0.54 mM iron generated maximum inhibitory effect as compared to Cu and Ni. The present study demonstrates that the test cyanobacterium exhibits metal and dose‐specific responses toward different physiological and biochemical processes.
Toxicity assessment of pollutants in the marine environment of Kuwait using Microbial bioassay
Authors: Salama M. S. , Salem A. A.
Published: October 2006

The Arabian Gulf offers a suitable location for investigating the potential impact of toxic chemicals on marine life, because it is a semienclosed, relatively shallow, small body of water. This study was carried out to evaluate the relative sensitivity, precision, and accuracy of three published microbial bioassay procedures to ascertain their ability to detect toxicity in the marine environment of Kuwait.

The bioassay procedures used were dissolved oxygen depletion (DOD), viable plate count (VPC), and optical density (OD). Mixed marine bacteria isolated from the local seawater of Kuwait was used, and test samples (pollutants) investigated include mercuric chloride (HgCl2), lindane, and a wastewater samples.

The DOD technique was evaluated as best for sensitivity of testing toxicity. In both brief and extended exposures, activity quotient values given by this technique were much lower than the LC50 and IC50 values given by the VPC and OD techniques. However, both VPC and OD techniques showed better reproducibility than the DOD technique, as indicated by lower coefficient of variation (CV) values. When evaluating complexity, the OD assay would be considered the least complex, then the DOD, and last would be the VPC.

Although both VPC and OD assays showed better reproducibility than the DOD technique, as indicated by lower CV values, the DOD demonstrated a higher sensitivity in detecting toxicity, and showed several other advantages such as rapidity and lower expenditure of routine assay requirements. However, the initiation of short‐term bioassay in Kuwait for predicting effect of pollutants in the marine environment is of necessity and importance.