A Critical Review of Discrete Soil Sample Data Reliability: Part 1—Field Study Results

Part 1 of this study summarizes data for a field investigation of contaminant concentration variability within individual, discrete soil samples (intra-sample variability) and between closely spaced, “co-located” samples (inter-sample variability). Hundreds of discrete samples were collected from three sites known respectively to be contaminated with arsenic, lead, and polychlorinated biphenyls. Intra-sample variability was assessed by testing soil from ten points within a minimally disturbed sample collected at each of 24 grid points. Inter-sample variability was assessed by testing five co-located samples collected within a 0.5-m diameter of each grid point. Multi Increment soil samples (triplicates) were collected at each study site for comparison. The study data demonstrate that the concentration of a contaminant reported for a given discrete soil sample is largely random within a relatively narrow (max:min <2X) to a very wide (max:min >100X) range of possibilities at any given sample collection point. The magnitude of variability depends in part on the contaminant type and the nature of the release. The study highlights the unavoidable randomness of contaminant concentrations reported in discrete soil samples and the unavoidable error and inefficiency associated with the use of discrete soil sample data for decision making in environmental investigations.     

Ecological Effects of Metals in Streams on a Defense Materials Processing Site in South Carolina,USA

The Savannah River Site (SRS) is a 780 km² U.S. Department of Energy facility near Aiken, South Carolina, established in 1950 to produce nuclear materials. SRS streams are “integrators” that potentially receive water transportable contaminants from all sources within their drainage basins, necessitating a watershed approach to organize contaminant distribution data and characterize the effects of multiple contaminants on aquatic organisms. This study used several lines-of-evidence to assess the ecological effects of metals in SRS streams, including contaminant exposure models for apex predators and bioassessments of fish and macroinvertebrate assemblages. Concentrations of metals in sediments, fish, and water were elevated in streams affected by SRS operations, but contaminant exposure models for the river otter Lontra Canadensis and belted kingfisher Ceryle alcyon indicated that toxicological reference values were exceeded only by Hg and Al. Macroinvertebrate assemblage structure was unrelated to sediment metal concentrations. Fish assemblage data were inconclusive. This study indicated that (1) modeling studies and field bioassessments provide a complementary basis for addressing the individual and cumulative effects of contaminants, (2) habitat effects must be controlled when assessing contaminant impacts, (3) sensitivity analyses of contaminant exposure models can help to apportion sampling effort, and (4) most individual metals in SRS streams are unlikely to have significant ecological effects.     

A covert contaminant of cultured plant cells: elimination of a Hyphomicrobium sp. from cultures of Datura innoxia (Mill.)

We have discovered a bacterial contaminant in some cell cultures of Datura innoxia (Mill.). The bacterium was tentatively identified as a species of Hyphomicrobium on the basis of its morphology and life cycle, and was isolated and grown in pure culture on a defined medium. The contaminant was not macroscopically observable in plant cell cultures. It caused neither a reduction of plant cell growth nor a noticeable increase in culture turbidity. Furthermore, it was not readily detectable by many standard assays for culture contamination: it would not grow alone in plant culture medium or yeast extract potato dextrose medium, and grew only very slowly on nutrient agar or beef-peptone medium. Repeated treatments with a combination of streptomycin (100 g/ml) and carbenicillin (100 g/ml) eliminated the contaminant from D. innoxia cell cultures without harming the plant cells.     

Passage ofCorynebacterium aquaticum through membrane filters

Summary Cellulose ester and polycarbonate membrane filters were tested for sterilizing capability with a contaminant,Corynebacterium aquaticum, isolated from cell culture medium. This contaminant, often found in water supplies, routinely passes filters of the polycarbonate type, but not of the cellulose ester type.C. aquaticum grows slowly requiring 7 to 10 days incubation in BME at 37°C before turbidity develops. Cryptic contamination is potentially a serious problem with this organism. This work was supported in part by USPHS Grant 5 F32 CA05635-02 from the National Cancer Institute.     

A method for the detection of Issatchenkia orientalis in a baker's yeast factory

Summary A method for the detection of Issatchenkia orientalis (Candida krusei), a contaminant of bakers' yeast, is described. Nine different liquid medium types were compared and maximum specific growth rates for the yeast contaminant were determined in each medium. Issatchenkia orientalis grew fastest in malt extract broth (0,37 h^-1) and potato dextrose broth (0,36 h^-1). Five antibiotics were tested for selective inhibition of seven different bakers' yeast strains in malt extract broth. Nystatin was the only antibiotic tested that inhibited the growth of all the bakers' yeast strains used, but did not affect the growth of I. orientalis.     

In vitro susceptibility to fungicides by invertebrate-pathogenic and saprobic fungi

The effect of five fungicides, benomyl (1 mg/l), dodine (50 mg/l), manzate (100 mg/l), cupric sulphate (200 mg/l) and thiabendazole (4 mg/l) was tested under in␣vitro conditions on development of 15 isolates of fungi pathogenic for insects and␣other invertebrates (Beauveria brongniartii, Culicinomyces clavisporus, Duddingtonia flagrans, Hirsutella thompsonii, two Metarhizium anisopliae, Nomuraea rileyi, two Isaria/Paecilomyces spp., and Sporothrix insectorum) and 13 isolates of contaminant fungi (five Aspergillus spp., Cladosporium cladosporioides, Cunninghamella echinulata, Fusarium roseum, Gliocladium sp., Mortierella isabellina, Mucor plumbeus, Rhizopus arrhizus and Trichothecium roseum) originating mostly from tree-hole breeding sites of mosquitoes. Most pathogenic and contaminant fungi had clear patterns of susceptibility or resistance to tested concentration of the fungicide. Development of both pathogenic and contaminant fungi on fungicide-supplemented medium varied among fungi and fungicides tested. Minimal inhibition of pathogenic fungi was found for cupric sulphate, benomyl, dodine, thiabendazole < manzate. The highest inhibition of contaminants was obtained with thiabendazole > benomyl and dodine > manzate and cupric sulphate. Thiabendazole was the most appropriate fungicide to isolate fungi pathogenic to invertebrates from substrates with high water contents and rich in organic material. The results underline the importance of adapting both a fungicide and its concentration for a selective medium for isolating specific target fungi and while selecting against possible contaminants.     

Differentiation between Gallionella and Metallogenium

Summary The DNA base composition and the sensitivity to iron of an ironoxidizing Metallogenium was determined. A comparison of the organism with Gallionella ferruginea suggests that the iron-oxidizing Metallogenium may be a common contaminant of G. ferruginea cultures.     

Sources of plant sterol contaminants encountered in low level steroid analysis

During development of an analytical method to characterize ligands to new members of the steroid hormone receptor superfamily, a persistant contaminant profile was observed during gas chromatographic analysis of reagent blanks. Mass spectrometric analysis identified three of the contaminant peaks as cholesterol and the plant sterols stigmasterol and sitosterol. Laboratory articles made of natural rubber, i.e. pipette fillers and latex gloves, were found to be the source of these and other compounds in the reagent blank profile.     

Root cause investigation of a viral contamination incident occurred during master cell bank (MCB) testing and characterization – A case study

An adventitious agent contamination occurred during a routine 9 CFR bovine viral screening test at BioReliance for an Eli Lilly Chinese Hamster Ovary (CHO) cell-derived Master Cell Bank (MCB) intended for biological production. Scientists from the sponsor (Eli Lilly and Company) and the testing service company (BioReliance) jointly conducted a systematic investigation in an attempt to determine the root cause of the contamination. Our investigation resulted in the identification of the viral nature of the contaminant. Subsequent experiments indicated that the viral contaminant was a non-enveloped and non-hemadsorbing virus. Transmission electron microscopy (TEM) revealed that the viral contaminant was 25–30 nm in size and morphologically resembled viruses of the family Picornaviridae. The contaminant virus was readily inactivated when exposed to acidic pH, suggesting that the viral contaminant was a member of rhinoviruses. Although incapable of infecting CHO cells, the viral contaminant replicated efficiently in Vero cell with a life cycle of 16 h. Our investigation provided compelling data demonstrating that the viral contaminant did not originate from the MCB. Instead, it was introduced into the process during cell passaging and a possible entry point was proposed. We identified the viral contaminant as an equine rhinitis A virus using molecular cloning and DNA sequencing. Finally, our investigation led us to conclude that the source of the viral contaminant was the equine serum added to the cell growth medium in the 9 CFR bovine virus test.     

New anamorphic yeast species: Candida infanticola sp. nov., Candida polysorbophila sp. nov., Candida transvaalensis sp. nov. and Trigonopsis californica sp. nov

Three new species of Candida and a new species of Trigonopsis are described based on their recognition from phylogenetic analysis of gene sequences from large subunit ribosomal RNA, ITS1/ITS2 rRNA, mitochondrial small subunit rRNA and cytochrome oxidase II. Candida infanticola sp. nov. (type strain NRRL Y-17858, CBS 7922) was isolated from the ear of an infant in Germany and is closely related to Candida sorbophila. Candida polysorbophila sp. nov. (type strain NRRL Y-27161, CBS 7317) is a member of the Zygoascus clade and was isolated in South Africa as a contaminant from an emulsion of white oil and polysorbate. Candida transvaalensis sp. nov. (type strain NRRL Y-27140, CBS 6663) was obtained from forest litter, the Transvaal, South Africa, and forms an isolated clade with Candida santjacobensis. Trigonopsis californica sp. nov. (type strain NRRL Y-27307, CBS 10351) represents a contaminant from wine in California, and forms a well-supported clade with Trigonopsis cantarellii, Trigonopsis variabilis and Trigonopsis vinaria.     

Inheritance Profile of Weathered Chlordane and P,P′-DDTs Accumulation by cucurbita pepo hybrids

Cucurbita pepo ssp pepo (zucchini) accumulates significant levels of persistent organic pollutants in its roots, followed by unexpectedly high contaminant translocation to the stems. Most other plant species, including the closely related C. pepo ssp ovifera (squash), do not have this ability. To investigate the mechanism of contaminant accumulation, two cultivars each of parental zucchini and squash, as well as previously created first filial (F1) hybrids and F1 backcrosses (BC) of those parental cultivars, were grown under field conditions in a soil contaminated with weathered chlordane (2.29 μg/g) and DDX residues (0.30 μg/g; sum of DDT, DDE, DDD). The parental zucchini had stem-to-soil bioconcentration factors (BCF, contaminant ratio of stem to soil) for chlordane and DDX of 6.23 and 3.10; these values were 2.2 and 3.7 times greater than the squash, respectively. Chlordane and DDX translocation factors, the ratio of contaminant content in the stems to that in the root, were 2.1 and 3.2 times greater for zucchini than for squash. The parental zucchini and squash also differed significantly in chlordane component ratios (relative amounts of trans-nonachlor [TN], cis-chlordane [CC], trans-chlordane [TC]) and enantiomer fractions for the chiral CC and TC. Hybridization of the parental squash and zucchini resulted in significant differences in contaminant uptake. For both the three separate component ratios (CR) and two sets of enantiomer fraction (EF) values, subspecies specific differences in the parental generation became statistically equivalent in the F1 hybrid zucchini and squash. When backcrossed (BC) with the original parental plants, the zucchini and squash F1 BC cultivars reverted to the statistically distinct CR and EF patterns. This pattern of trait segregation upon hybridization suggests either single gene or single locus control for persistent organic pollutant (POP) uptake ability by C. pepo ssp pepo.     

Emulsification and utilization of high-speed diesel by a <Emphasis Type="Italic">Brevibacterium </Emphasis>species isolated from hydraulic oil

Summary A contaminant of hydraulic oil has been isolated and identified using conventional microbiological and biochemical techniques. The PCR amplification and sequencing of 16S-rDNA indicated it to be a Brevibacterium sp. closely related to B. casei strain DSM 20657, based on sequence homology (98%). In view of being an oil contaminant, its ability of high speed diesel (HSD) emulsification and utilization have been studied and compared with two strains of Pseudomonas putida (MTCC2445 and Biotype-A MTCC 1274) and Pseudomonas fluorescens (MTCC670). After enrichment in minimal medium containing HSD as sole source of carbon Brevibacterium sp. (Met-1) was grown in Bushnell Haas broth containing 0.4% HSD (w/v). Bacterial growth at 28 °C, oil utilization, emulsification and surface active properties were determined after 5 days of incubation and compared with type cultures. All bacteria were found to grow well in the presence of HSD at the tested concentration. However, better utilization of HSD was observed in the Brevibacterium Met-1 isolate and Pseudomonas putida (MTCC 2445).     

Intrinsic bioremediation in a solvent-contaminated alluvial groundwater

An industrial site contaminated with a mixture of volatile organic compounds in its subsurface differed from previously reported locations in that the contamination consisted of a mixture of chlorinated, brominated, and non-halogenated aromatic and aliphatic solvents in an alluvial aquifer. The source area was adjacent to a river. Of the contaminants present in the aquifer, benzene, toluene, and chlorobenzene (BTC) were of primary concern. Studies of the physical, chemical, and microbiological characteristics of site groundwater were conducted. The studies concentrated on BTC, but also addressed the fate of the other aquifer VOCs. Gas chromatographic analyses performed on laboratory microcosms demonstrated that subsurface microorganisms were capable of BTC degradation. Mineralization of BTC was demonstrated by the release of ¹⁴CO₂ from radiolabelled BTC. In the field, distribution patterns of nutrients and electron acceptors were consistent with expression of in situ microbial metabolic activity: methane, conductivity, salinity and o-phosphate concentrations were all positively correlated with contaminant concentration; while oxidation-reduction potential, nitrate, dissolved oxygen and sulfate concentrations were negatively correlated. Total aerobes, aerotolerant anaerobes, BTC-specific degraders, and acridine orange direct microscopic microorganism counts were strongly and positively correlated with field contaminant concentrations. The relative concentrations of benzene and toluene were lower away from the core of the plume compared to the less readily metabolized compound, chlorobenzene. Hydrodynamic modeling of electron-acceptor depletion conservatively estimated that 450 kg of contaminant have been removed from the subsurface yearly. Models lacking a biodegradation term predicted that 360 kg of contaminant would reach the river annually, which would result in measurable contaminant concentrations. River surveillance, however, has only rarely detected these compounds in the sediment and then only at trace concentrations. Thus, the combination of field modeling, laboratory studies, and site surveillance data confirm that significant in situ biodegradation of the contaminants has occurred. These studies establish the presence of intrinsic bioremediation of groundwater contaminants in this unusual industrial site subsurface habitat. Received 01 December 1995/ Accepted in revised form 27 July 1996     

Phytoremediation of Soils Contaminated with Wood Preservatives: Greenhouse and Field Evaluations

Phytoremediation was evaluated as a potential treatment for the creosote-contaminated surface soil at the McCormick and Baxter (M&B) Superfund Site in Portland, Oregon. Soil at the M&B site is contaminated with pentachlorophenol (PCP) and polyaromatic hydrocarbons (PAHs). Eight individual PAH compounds (containing four to six aromatic rings) were included in the investigation. Greenhouse and field studies were carried out using perennial ryegrass (Lolium perenne). The following three treatments were compared in both studies: T1 = planted-amended soil; T2 = unplanted-amended soil; and T3 = unplanted-unamended soil. The amendments were mineral nutrients and dolomite, which was used to raise the acidic pH of the soil. Contaminant concentrations in the soil were measured initially and at regular intervals for several months. In the greenhouse study, the concentrations of certain contaminants decreased as a function of time. Thus, PCP, fluoranthene, pyrene, chrysene, and benzo(k)fluoranthene appeared to undergo biodegradation in all of the treatments. On the other hand, certain larger molecular weight PAHs were relatively recalcitrant. These “recalcitrant PAHs” included benzo(b)fluoranthene, benzo(a)pyrene, benzo(g,h,i)perylene and indeno(1,2,3-cd)pyrene. Statistical methods were used to compare the concentrations of the more easily biodegraded contaminants in treatments T1, T2, and T3. The statistical analysis was facilitated by normalizing the contaminant concentrations relative to the sum of the recalcitrant PAHs in the same sample. Thus, ratios were created that could be compared directly to benchmark values indicative of the contaminant at the beginning of the study. In the greenhouse study, statistically significant differences between T1 and T2, across all treatment times, were obtained for fluoranthene, pyrene, and chrysene (p ≤0.05), suggesting enhanced rhizosphere biodegradation for these compounds. Significant differences between T2 and T3 were obtained for pyrene (p ≤0.03), indicating that nutrients stimulated the biodegradation of this contaminant. Although the greenhouse study was carried out with a well-mixed soil sample from the M&B site, an extremely uneven distribution of contaminants was encountered in the field study. The resulting scatter in the field data made comparisons difficult, and treatment-specific effects observed in the greenhouse study were not statistically significant in the field study. However, analysis of the normalized data from the field revealed the same time-dependent decreases in contaminant concentration as observed in the greenhouse study.     

Intermediate accumulation of metabolites results in a bottleneck for mineralisation of the herbicide metabolite 2,6-dichlorobenzamide (BAM) by Aminobacter spp

Degradation and mineralisation of the groundwater contaminant 2,6-dichloro-benzamide (BAM) was investigated in two Aminobacter strains focussing on the induction of BAM degradation and mineralisation and occurrence of intermediate metabolites. The BAM degradation rate was independent of whether the cells were pre-grown in the absence or presence of BAM, thus indicating that the first step in the degradation pathway was constitutively expressed. In contrast, ¹⁴CO₂ production was stimulated when cells were pre-grown in the presence of BAM, suggesting that one or more of the subsequent steps in the degradation pathway were inducible. Accumulation of 2,6-dichlorobenzoate (DCBA) during degradation of BAM demonstrated that the first step involved amidase activity. Mass balance calculations and thin-layer chromatography coupled with autoradiographic detection indicated that degradation of DCBA and at least one unknown metabolite may comprise a bottleneck for BAM mineralisation by Aminobacter spp. The study thus provides novel information about the BAM degradation pathway and points to the involvement of unknown intermediate metabolites in degradation of this important groundwater contaminant.     

Efficacy of carboxin and heat treatment for controlling the growth of Sclerotium rolfsii during culture of the mushroom Pleurotus flabellatus

Soaking paddy straw for 18 h in a carboxin suspension in water (5 mg a.i./l) effectively controlled the growth of Sclerotium rolfsii occurring as a natural contaminant in paddy straw, during culture of the mushroom Pleurotus flabellatus. Carboxin at this concentration delayed sporophore formation by 2–3 days, but did not affect total yield. No detectable carboxin residues were found in the mushrooms grown on the treated paddy straw. Treatment of the paddy straw with hot water at 60°C for 10 min completely controlled the contaminant without affecting mushroom growth and yield; but 20 mm treatments with hot air at 60°C or heating with the steam to 75–80°C did not control S. rolfsii.     

A Hydroponic System for Growing Gnotobiotic Vs. Sterile Plants to Study Phytoremediation Processes

In some phytoremediation studies it is desirable to separate and define the specific contribution of plants and root-colonizing bacteria towards contaminant removal. Separating the influence of plants and associated bacteria is a difficult task for soil root environments. Growing plants hydroponically provides more control over the biological factors in contaminant removal. In this study, a hydroponic system was designed to evaluate the role of sterile plant roots, rhizodeposition, and root-associated bacteria in the removal of a model contaminant, phenol. A strain of Pseudomonas pseudoalcaligenes that grows on phenol was inoculated onto plant roots. The introduced biofilm persisted in the root zone and promoted phenol removal over non-augmented controls. These findings indicate that this hydroponic system can be a valuable tool for phytoremediation studies that investigate the effects of biotic and abiotic factors on pollution remediation.     

Contamination and persistent infection ofDrosophila cell lines by reovirus type particles

Summary A new type of contaminant particles persistently infectedDrosophila cell lines. On an ultrastructural, morphogenetic and histochemical basis, they are similar to viruses of the Reoviridae group. They have been namedDrosophila K virus (DKV).     

Environmental conditions and the performance of free water surface flow constructed wetland: a multivariate statistical approach

During the past three decades, constructed wetlands have become an integral part of the suite of technologies for removing domestic and industrial wastewater contaminants. The use of constructed wetlands has disproportionately focused on domestic and agricultural wastewaters and storm water runoff and less on oil and gas-related produced water. In this context, the cumulative effect of environmental factors on the treatment/removal efficiency of contaminants in produced water is underserved by research. Therefore, this study assessed the effect of environmental factors (temperature, dissolved oxygen, oxidation–reduction potential, and pH) on contaminant removal efficiency in free water surface flow constructed wetland (FWSFCW) using ordinary least squares regression and experimental data from a waste treatment facility in Ghana. The results showed that environmental factors did not systematically vary across the experimental group and control set-up. Generally, the environmental factors explained relatively far less of the variance in contaminant removal efficiency compared with the plant species (Typha latifolia, Ruellia simplex and Alternanthera philoxeroides). Environmental factors cumulatively explained only 1.3%, 16.4%, 22.6%, and 5.6% of the variance in removal efficiency of BOD, COD, oil and grease, and total coliform bacteria, respectively. Temperature was the most important environmental predictor of the removal of BOD and phosphorus whereas DO was most important for removing nitrates and total coliform bacteria. ORP and pH were the most important predictors of COD, and oil and grease, respectively. These findings underscore the complex relationships among environmental factors and contaminant removal efficiency and the need for contaminant management practices and remedial techniques that address these complexities.

     

Bacterial virus contamination of fetal bovine sera

Summary Thirty-seven lots of fetal bovine sera were examined for the presence ofEscherichia coli-specific bacterial viruses, and 23 were positive. No correlation was found between the presence of bacterial virus and poor growth-promoting qualities of the sera. One bacterial virus contaminant of fetal bovine serum was isolated and examined by electron microscopy.