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At least 37 records · Page 2Linked to original sources

PubMed2003

Contaminant risks from biosolids land application: contemporary organic contaminant levels in digested sewage sludge from five treatment plants in Greater Vancouver, British Columbia.

This study examines the potential for environmental risks due to organic contaminants at sewage sludge application sites, and documents metals and various potential organic contaminants (volatile organics, chlorinated pesticides, PCBs, dioxins/furans, extractable petroleum hydrocarbons, PAHs, phenols, and others) in current production biosolids from five wastewater treatment plants (WWTPs) within the Greater Vancouver Regional District (GVRD). There has been greater focus in Europe, North America and elsewhere on metals accumulation in biosolids-amended soil than on organic substances, with the exception of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans. Another objective, therefore, was to evaluate the extent to which management of biosolids re-use based on metal/metalloid levels coincidentally minimizes environmental risks from organic contaminants. Historical-use contaminants such as chlorophenols, PCBs, and chlorinated pesticides were not detected at environmentally relevant concentrations in any of the 36 fresh biosolids samples, and appear to have virtually eliminated from sanitary collection system inputs. The few organic contaminants found in freshly produced biosolids samples that exhibited high concentrations relative to British Columbia and Canadian soil quality benchmarks included p-cresol, phenol, phenanthrene, pyrene, naphthalene, and heavy extractable petroleum hydrocarbons (HEPHs--nCl9-C34 effective carbon chain length). It was concluded that, with the exception of these petroleum hydrocarbon constituents or their microbial metabolites, the mixing of biosolids with uncontaminated soils during land application and based on the known metal concentrations in biosolids from the Greater Vancouver WWTPs investigated provides adequate protection against the environmental risks associated with organic substances such as dioxins and furans, phthalate esters, or volatile organics. Unlike many other organic contaminants, the concentrations of petroleum hydrocarbon derived substances in biosolids has not decreased within the last decade or more in the WWTPs studied, and--unlike persistent chlorinated compounds--the associated PAHs and other hydrocarbon constituents merit careful consideration, especially in the context of repeated land-application of biosolid.

Canada↗

PubMed2005

Percutaneous absorption of 4-cyanophenol from freshly contaminated soil in vitro: effects of soil loading and contamination concentration.

Despite the skin's excellent barrier function, dermal exposure to soil contaminated with toxic chemicals can represent a significant health hazard (e.g., via multiple work related contacts in the farming and waste disposal industries). The development of environmental standards or limits for chemical levels in soil has been impeded because quantification of percutaneous uptake from this medium has not been well-defined. The objective of the research described here, therefore, was to better characterize the rate and extent of dermal penetration as a function of soil loading and degree of soil contamination. The absorption of a model compound (4-cyanophenol, CP) across hairless mouse skin in vitro has been determined at four different soil loadings (5, 11, 38 and 148 mg cm-2) and at six levels of soil contamination (concentrations ranging from 0.19 to 38 mg/g soil). Following 8 h of exposure, the amount of CP absorbed was independent of soil loading when CP concentration was constant, implying that the quantity of soil presentwas always sufficientto provide atleast a single layer of tightly packed particles. At the lowest loadings, however, with increasing times of exposure, the CP transport rate fell off due to depletion of chemical from the soil. At constant soil loading (38 mg cm(-2)), CP flux (Jss) across the skin was linearly proportional to the level of contamination (C(o)soil) over the range 0.19 to 23.5 mg of CP per gram of soil: Jss (micorg cm(-2) h(-1)) = (1.1 x 10(-5) g cm(-2) h(-1)) x Csoil (microg/g soil). At the highest CP contamination concentration, however, the transport rate was about an order of magnitude higher than expected, possibly due to the presence of pure CP crystals. In conclusion, these results provide new quantifications of the characteristics of dermal uptake from chemically contaminated soils and important information with which to develop and verify predictive models of dermal absorption.

Administration, Cutaneous↗

PubMed2005

Extraction behavior of metallic contaminants and soil constituents from contaminated soils.

With an aim of developing an effective remediation technology for soils contaminated by heavy metals and metalloids, the extraction behavior of metallic contaminants as well as those of soil constituents was studied on a laboratory scale. Three contaminated soils collected from a former metal recycling plant were examined. These three soils were found to be contaminated by As, Cu, Pb, Sb, Se and Zn as compared to the non-contaminated soil. The pH-dependent extraction behavior of various elements from the soils was measured in a wide pH range and categorized into three groups. Hydrochloric acid (HCl), H2SO4, H3PO4, HNO3, sodium citrate, sodium tartrate, disodium dihydrogen ethylenediaminetetraacetate and diethylenetriaminepentaacetic acid were evaluated as extractants for removing contaminants from the soils. Extraction behavior of the soil constituents was also studied. The efficiency of the extraction was evaluated by the Japanese content and leaching tests. The stabilization of Pb remaining in the soil after the extraction process was conducted by the addition of iron(III) and calcium chloride.

Hydrogen-Ion Concentration↗

PubMed2001

Influence of preharvest tumor cell contamination in bone marrow or blood does not predict resultant tumor cell contamination of granulocyte colony-stimulating factor mobilized stem cells.

Tumor cell contamination of stem cell collections harvested from breast cancer patients is a common phenomenon described by several investigators but with findings that vary among reports. Although so-called co-mobilization of these cells has been hypothesized, the origin of tumor cell contamination in stem cells is still unknown. A total of 47 G-CSF mobilized stem cell grafts from patients with nodal-positive (n = 30), chemosensitive metastatic (n = 11), and 5 women with inflammatory breast cancer were evaluated for cancer cells by immunocytochemistry. Additionally, 40 bone marrow aspirations and 23 peripheral blood samples collected prior to apheresis and after one to two cycles of conventional chemotherapy were available for examination. Tumor cell contamination of leukapheresis correlated best with preharvest blood state. This was valid when the nominal (positive/negative) presence of tumor cells in blood was compared to the nominal presence of tumor cells in apheresis samples and when the it was correlated to the tumor cell load of apheresis samples (TCL = tumor cells per 10(6) nucleated cells investigated). The correlation between blood and stem cells was better (nominal and quantitative) than that between marrow and stem cells, despite the larger sample size of marrow aspirations. The presence or absence of cancer cells in apheresis samples could not be safely predicted by the presence or absence of tumor cells in marrow or blood alone. Diagnostic specificity seems to improve from a combination of results from marrow and blood analysis. No correlation was found in quantitative analysis of tumor cell contamination between marrow and blood. In conclusion, the results suggest that blood and bone marrow represent different compartments for epithelial cancer cells and that contaminating tumor cells in stem cell harvests may be derived from the blood and/or marrow compartment. The tumor cell contamination of a stem cell harvest cannot be safely predicted by a preceding blood or marrow analysis.

Bone Marrow↗

PubMed1994

Contamination of central venous catheters: use of infusion-lines does not increase catheter-contamination.

In a prospective controlled trial we compared the rates of intraluminal contamination between the two lumens of a double-lumen central venous catheter. One lumen was used for repeat infusions and injections, and the other was permanently connected to a slow infusion of 0.9% NaCl. The study was designed so that the patient was his own control. Twenty-eight catheters were examined and comparison with catheter-tip cultures was performed in 24. Intraluminal culture was performed 67-77 h after insertion of the catheter and catheter-tip culture was performed on removal of the catheter. The contamination rate from catheter-tips was 20.8%, which is acceptable compared with other studies. There was only one positive intraluminal culture in each group (3.6%), and thus no correlation was found between contamination rate and the number of times the infusion-line had been interrupted for use. As for catheter-tip contamination, we found no correlation between infusion of blood-products or parenteral nutrition and contamination rates.

Blood Transfusion↗

PubMed2004

Foliar contamination of Phaseolus vulgaris with aerosols of 137Cs, 85Sr, 133Ba and 123mTe: influence of plant development stage upon contamination and rain.

As part of a requirement to improve the assessment of the impact of radioactive fallout on consumed agricultural products, bean plants at four development stages (seedlings, preflowering, late flowering and mature plants) were contaminated by dry deposition of (137)Cs, (85)Sr, (133)Ba and (123m)Te aerosols. The influence of two rain scenarios and of the development stage upon contamination on interception, retention, and translocation to pods was studied. Interception of the four radionuclides was almost identical and varied from 30 to 60% with increasing development stage. The most important rain parameter was the time which elapsed between contamination and the first rain. Whatever the development stage, rain washed off more cesium from the leaves when it occurred 2 days after the deposit (37% at the seedling stage, for example) rather than later on (6 days, 27%), due to rapid migration of Cs in the plant. The first rain washed off nearly 40% of Ba whatever the scenario. For later stages, Sr and Ba were more washed off by heavy weekly rains than by weak twice-a-week rains, perhaps because of the Sr/Ba-contaminated material loss associated with wash off (desquamation of cuticles). Te showed little wash off (less than 5%). Wash off decreased with an older development stage for a weak rain intensity, due to the superimposition of leaves. Heavy rains removed this shelter effect. At harvest, rain effect was no longer detectable as foliar activity was similar for both rain scenarios. Translocation factors (TF) for strontium and barium increased from 6 x 10(-3) to 1 x 10(-1) with the plant development stage upon contamination, whereas those for cesium remained almost unchanged between 2 x 10(-1) and 4 x 10(-1). Flowering is the most critical stage towards residual contamination in pods at harvest, with the exception of direct deposit on pods at the mature stage (TF values are one order of magnitude higher). TF value for Te was 6.5 x 10(-2) and was due to direct deposit. Modelling reflected the trends, through the differential values of the wash off and absorption coefficients, of what was reported for experimental results.

Aerosols↗

PubMed2003

Modified syringe design prevents plunger-related contamination--results of contamination and flow-rate tests.

The usual mechanism for syringe contamination is spread of micro-organisms along the inside of the barrel. Two or more full strokes of the plunger will inevitably transport a contaminant from the inside wall into the sterile compartment. We modified syringes by replacing the plunger with a modified version that has an additional central O-ring seal. Conventional and modified syringes were tested for their susceptibility to contamination using standard microbiological and radioisotope methods, and the flow-rate stability of the modified syringe design was assessed in a model with commercially available infusion pumps. Although conventional syringes consistently became contaminated with the second full excursion of the plunger, no contamination was observed in modified syringes, even after 100 aspiration/injection cycles. With respect to flow-rate stability, the new syringe design complies with DIN (German Institute for Standardization) standards.

Cross Infection↗

PubMed1989

Microbial contamination of arterial infusions used for hemodynamic monitoring: a randomized trial of contamination with sampling through conventional stopcocks versus a novel closed system.

Arterial catheters are now commonly used to monitor blood pressure and obtain blood samples for arterial blood gas and other laboratory determinations. Stopcocks inserted into the pressure monitoring circuit have been the primary means of obtaining blood from arterial catheters. However, these stopcock systems have been associated with nosocomial contamination and bacteremias. Because of the problems of bacterial contamination and blood wasting with the stopcock sampling systems, we compared the frequency and extent of contamination of external sampling ports and the monitoring tubing fluid in stopcocks with that of a novel closed needle-sampling system (Lab-Site, Migada Ltd, Rehovot, Israel), incorporated into pressure monitoring tubing (Abbott Laboratories Inc., North Chicago, Illinois). We found that use of the novel sampling system resulted in significantly fewer episodes of internal bacterial contamination of the arterial monitoring line (7%) than did the use of a stopcock system (61%). External contamination of the sampling port was also lower in the novel system (8%) than in the stopcock system (37%). This suggests that the closed system may reduce the risk of nosocomial infections in patients requiring arterial pressure monitoring.

Adult↗

PubMed2005

Surface contamination of cyclophosphamide packaging and surface contamination with antineoplastic drugs in a hospital pharmacy in Sweden.

Workplaces, e.g. hospital pharmacies and hospital departments, where antineoplastic drugs are handled might be contaminated with these drugs, and pharmacy personnel and health care workers may be exposed. In this study potential sources for exposure of antineoplastic drugs were investigated. Unbroken drug vials and tablet blister packages, both containing cyclophosphamide (CP) and their outer packaging were wipe sampled. Analysis was performed by liquid chromatography combined with tandem mass spectrometry (LC-MS/MS). The result showed that almost every part of the primary packaging was contaminated with CP and ifosfamide (IF). However, the amounts of CP and IF were low, and most likely not harmful for the personnel handling these packaging in association with drug preparation. The contamination must originate from the pharmaceutical manufacturer. Different surfaces in the preparation unit of a Swedish hospital pharmacy were also investigated at two different occasions by wipe sampling. In the preparation unit CP and IF were found as contaminants on the majority of the investigated surfaces. After the first measurement the hospital pharmacy improved its routines. Lower amounts of CP and IF were detected at the second measurement. A low degree of contamination with CP and IF was also detected on the floor outside the preparation unit and this indicated a small distribution of antineoplastic drugs to the surroundings.

Antineoplastic Agents↗

PubMed2004

Resrad-recycle: a computer model for analyzing radiation exposures resulting from recycling radioactively contaminated scrap metals or reusing radioactively surface-contaminated materials and equipment.

RESRAD-RECYCLE is a computer code designed by Argonne National Laboratory (ANL) to be used in making decisions about the disposition of radioactively contaminated materials and scrap metals. It implements a pathway analysis methodology to evaluate potential radiation exposures resulting from the recycling of contaminated scrap metals and the reuse of surface-contaminated materials and equipment. For modeling purposes, it divides the entire metal recycling process into six steps: (1) scrap delivery, (2) scrap melting, (3) ingot delivery, (4) product fabrication, (5) product distribution, and (6) use of finished product. RESRAD-RECYCLE considers the reuse of surface-contaminated materials in their original forms. It contains representative exposure scenarios for each recycling step and the reuse process; users can also specify scenarios if desired. The model calculates individual and collective population doses for workers involved in the recycling process and for the public using the finished products. The results are then used to derive clearance levels for the contaminated materials on the basis of input dose restrictions. The model accounts for radiological decay and ingrowth, dilution and partitioning during melting, and distribution of refined metal in the various finished products, as well as the varying densities and geometries of the radiation sources during the recycling process. A complete material balance in terms of mass and radioactivity during the recycling process can also be implemented. In an international validation study, the radiation doses calculated by RESRAD-RECYCLE were shown to agree fairly well with actual measurement data.

Body Burden↗

PubMed2005

DNA extraction from low-biomass carbonate rock: an improved method with reduced contamination and the low-biomass contaminant database.

Caves represent a unique environment in which to study subsurface geomicrobial interactions and processes. One of the primary techniques used to study such geologic samples is molecular phylogenetic analysis, but this technique is hampered by low microbial biomass and calcium in the host rock, often leading to poor and irreproducible DNA extraction. We describe an improved protocol to recover extremely low amounts of DNA from calcium-rich geologic samples. This protocol relies on the use of the synthetic DNA molecule poly-dIdC, to act both as blocking agent and carrier molecule to increase the yield of DNA, and dialysis to remove calcium inhibitors of PCR amplification. Further, we demonstrate that many traditionally used laboratory substrates contain microbial DNA that can be amplified through the polymerase chain reaction (PCR) and contaminate molecular phylogenetic profiles. While the number of potential contaminants can be minimized, it cannot be eliminated from extraction techniques. We have therefore established the low-biomass contaminant (LBC) database, which contains the 16S rRNA gene sequences of species that have been identified as common laboratory contaminants. These identified contaminants provide a reference database to allow investigators to critically evaluate certain species identified within their phylogenetic profile when examining such low-biomass environments.

Base Sequence↗

PubMed2005

A preliminary study on mercury contamination to the environment from artisanal zinc smelting using indigenous methods in Hezhang County, Guizhou, China: Part 2. Mercury contaminations to soil and crop.

Artisanal zinc smelting using indigenous method in Hezhang County, Guizhou, China has posed seriously environmental pollution to the local environment. Within less than 150 km2 area in Hezhang, a few metric tons of mercury were released into the atmosphere each year since 1989 due to artisanal zinc smelting, and the surface waters were seriously contaminated with mercury. For the first time, we investigated the mercury contamination to the local soil and crop compartments due to mercury emissions from artisanal zinc smelting activities in this area. Mercury distribution patterns in 5 soil profiles collected in artisanal zinc smelting area showed that the top soils were seriously contaminated with mercury. The soils from agriculture land close to the zinc smelting areas were also contaminated with mercury due to the deposition of mercury species that emitted from artisanal zinc smelting processes. Total mercury concentrations in top soils decrease exponentially with distance from the zinc smelting area. Corn plants that were cultivated in agriculture land close to the zinc smelting area were also contaminated with mercury. Mercury concentration in corn plant tissue increased in the order of grains<stalks<roots<leaves. The average total mercury concentration in grain tissue was 0.011 mg kg-1, and the highest concentration reached 0.026 mg kg-1, exceeding the national guidance limit for foodstuff other than fish. Uptake of gaseous mercury was the predominant pathway by which Hg accumulated in the foliage, and mercury in root tissue is mainly derived from soil.

China↗

PubMed2006

External contamination of hair with cocaine: evaluation of external cocaine contamination and development of performance-testing materials.

The National Laboratory Certification Program undertook an evaluation of the dynamics of external contamination of hair with cocaine (COC) while developing performance testing materials for Federal Drug-Free Workplace Programs. This characterization was necessary to develop performance materials that could evaluate the efficacy of hair testing industry's decontamination procedures. Hair locks (blonde to dark brown/black) from five different individuals were contaminated with cocaine HCl. Hair locks were then treated with a synthetic sweat solution and hygienic treatments to model real-life conditions. Hair locks were shampooed daily (Monday through Friday) for 10 weeks, and samples of the hair locks were analyzed for COC, benzoylecgonine (BE), cocaethylene (CE), and norcocaine (NCOC). Three commercial analytical laboratories analyzed samples under three protocols: no decontamination procedure, individual laboratory decontamination, or decontamination by an extended buffer procedure at RTI International. Results indicated substantial and persistent association of all four compounds with all hair types. Hair that was not decontaminated had significantly greater quantities of COC and BE than did hair that was decontaminated. The only hair samples below detection limits for all four compounds were those decontaminated 1 h after contamination. Additionally, BE/COC ratios increased significantly over the 10-week study (regardless of decontamination treatment). From 21 days postcontamination until the end of the study, the mean BE/COC ratio for all hair types exceeded 0.05, the proposed Federal Mandatory Guidelines requirement. The largest variability in results was observed for samples decontaminated by participant laboratories. This suggests that current laboratory decontamination strategies will increase variability of performance testing sample results. None of the decontamination strategies used in the study were effective at removing all contamination, and some of the contaminated hair in this study would have been reported as positive for cocaine use based on the proposed Federal Mandatory Guidelines.

Cocaine↗

PubMed2006

IDEAS internal contamination database: a compilation of published internal contamination cases. A tool for the internal dosimetry community.

In the scope of the IDEAS project to develop General Guidelines for the Assessment of Internal Dose from Monitoring data, two databases were compiled. The IDEAS Bibliography database contains references dealing with problems related to cases of internal contamination. The IDEAS Internal Contamination Database now contains more than 200 cases of internal contamination. In the near future, the IDEAS Internal Contamination database will be made available to the internal dosimetry community. The database has several potential applications, including: training, testing biokinetic models, testing software for calculating intakes and doses from bioassay data, comparison of data from a new accidental intake with that from previous exposures to similar materials. The database is by no means complete, and this presentation is also an appeal for internal contamination cases to extend and update it.

Biological Assay↗

PubMed2001

Coccidial contamination of raspberries: mock contamination with Eimeria acervulina as a model for decontamination treatment studies.

Numerous outbreaks have been reported since 1995 in the United States and Canada that were linked to the consumption of imported fresh raspberries contaminated with Cyclospora. Because Cyclospora has no laboratory animal hosts, Eimeria acervulina, a common chicken coccidium similar in characteristics to Cyclospora, was used as a surrogate to test decontamination treatments. Raspberries were mock contaminated with E. acervulina-sporulated oocysts in a water suspension, then exposed to washing, freezing, heat, or irradiation before they were fed to chicks. The presence of oocysts in the contaminated raspberries was confirmed either by duodenal lesions or oocysts in cecal contents 5 days postinoculation (PI) or in fecal contents 6 days PI, after 24 h of fecal collection. Washing of raspberries was generally not adequate in removing coccidial contamination, but freezing and heat treatment appeared effective. Gamma irradiation of E. acervulina-sporulated oocysts at a dose of 0.5 kGy was partially effective, but it was completely effective at 1.0 kGy and higher. We suggest that E. acervulina, for mock contamination of raspberries and subsequent decontamination treatments, is easy to handle, safe, and economical to study.

Animals↗

PubMed2004

[Biological treatments for contaminated soils: hydrocarbon contamination. Fungal applications in bioremediation treatment].

Bioremediation is a spontaneous or controlled process in which biological, mainly microbiological, methods are used to degrade or transform contaminants to non or less toxic products, reducing the environmental pollution. The most important parameters to define a contaminated site are: biodegradability, contaminant distribution, lixiviation grade, chemical reactivity of the contaminants, soil type and properties, oxygen availability and occurrence of inhibitory substances. Biological treatments of organic contaminations are based on the degradative abilities of the microorganisms. Therefore the knowledge on the physiology and ecology of the biological species or consortia involved as well as the characteristics of the polluted sites are decisive factors to select an adequate biorremediation protocol. Basidiomycetes which cause white rot decay of wood are able to degrade lignin and a variety of environmentally persistent pollutants. Thus, white rot fungi and their enzymes are thought to be useful not only in some industrial process like biopulping and biobleaching but also in bioremediation. This paper provides a review of different aspects of bioremediation technologies and recent advances on ligninolytic metabolism research.

Basidiomycota↗

PubMed2005

Several physical properties of aflatoxin-contaminated pistachio nuts: application of BGY fluorescence for separation of aflatoxin-contaminated nuts.

The primary objective was to evaluate and find a proper method for visual identification of aflatoxin-contaminated pistachio nuts. The feasibility of using bright greenish yellow fluorescence (BGYF) in pistachio nut as a discriminating factor for identification of Aspergillus flavus-infested nuts, at harvest and in post-harvest, is investigated. Results show a strong relationship between BGYF and aflatoxin content at harvest. The factors affecting the application of this method in post-harvest stages are also discussed. The relationship between inside-brown kernels and aflatoxin presence is confirmed. At harvest, the brown kernels are a subdivision of fluorescent fraction. The share of different pistachios based on hull types (with sound hull, growth split and early-split) in contamination is studied. The early-split nuts are the most contaminated nuts, growth split nuts are less contaminated, and pistachios with sound hulls are almost clean. The effect of inappropriate handling on the percentage of fluorescent nuts is studied. The percentage of visible mould in samples is observed which shows a good relationship with the presence of BGY fluorescence.

Aflatoxins↗

PubMed2002

Contamination of toothbrush at different time intervals and effectiveness of various disinfecting solutions in reducing the contamination of toothbrush.

The common devices used for oral hygiene measures are toothbrush, dentifrice and oral rinses. Present study was carried out to know the level of contamination of toothbrush after brushing and at the same time, to know the efficacy of various disinfecting solution in reducing their contamination. Thirty two children in the age group of 12-14, residing in Government Hostel were selected. They were divided into four groups of 8 each, and were supplied with toothbrushes. Toothbrushes were cultured to assess the contamination at different time intervals. Control group had shown the highest percentage of contamination. It was concluded that cleaning of the oral cavity is not the only procedure in maintaining the oral hygiene, the oral hygiene devices should also be kept clean.

Adolescent↗