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PubMed2001

Elucidation of Listeria monocytogenes contamination routes in cold-smoked salmon processing plants detected by DNA-based typing methods.

The contamination routes of Listeria monocytogenes in cold-smoked salmon processing plants were investigated by analyzing 3,585 samples from products (produced in 1995, 1996, 1998, and 1999) and processing environments (samples obtained in 1998 and 1999) of two Danish smokehouses. The level of product contamination in plant I varied from 31 to 85%, and no L. monocytogenes was found on raw fish (30 fish were sampled). In plant II, the levels of both raw fish and product contamination varied from 0 to 25% (16 of 185 raw fish samples and 59 of 1,000 product samples were positive for L. monocytogenes). A total of 429 strains of L. monocytogenes were subsequently compared by random amplified polymorphic DNA (RAPD) profiling, and 55 different RAPD types were found. The RAPD types detected on the products were identical to types found on the processing equipment and in the processing environment, suggesting that contamination of the final product (cold-smoked salmon) in both plants (but primarily in plant I) was due to contamination during processing rather than to contamination from raw fish. However, the possibility that raw fish was an important source of contamination of the processing equipment and environment could not be excluded. Contamination of the product occurred in specific areas (the brining and slicing areas). In plant I, the same RAPD type (RAPD type 12) was found over a 4-year period, indicating that an established in-house flora persisted and was not eliminated by routine hygienic procedures. In plant II, where the prevalence of L. monocytogenes was much lower, no RAPD type persisted over long periods of time, and several different L. monocytogenes RAPD types were isolated. This indicates that persistent strains may be avoided by rigorous cleaning and sanitation; however, due to the ubiquitous nature of the organism, sporadic contamination occurred. A subset of strains was also typed by using pulsed-field gel electrophoresis and amplified fragment length polymorphism profiling, and these methods confirmed the type division obtained by RAPD profiling.

Animals↗

PubMed2005

Bleeding sap and old wood are the two main sources of contamination of merging organs of vine plants by Xylophilus ampelinus, the causal agent of bacterial necrosis.

The spatial distribution of vine plants contaminated by Xylophilus ampelinus, the agent responsible for bacterial necrosis, was studied over a 5-year period within two vineyards in the Cognac area. Both vineyards were planted with Vitis vinifera cv. Ugni blanc but were different in age and agronomic location. The emission of X. ampelinus in contaminated bleeding sap was observed during vine sprouting. Contaminated bleeding sap is an important source of inoculum for external contamination due to the high susceptibility of young merging shoots to the pathogen. X. ampelinus emission by bleeding sap was not affected by the age of the plants or the location of the vineyards. However, its emission was irregular with time, and it varied between two fruit canes from individual plants and between plants as well as between years. Moreover, the two vineyards appeared to be entirely contaminated. Consequently, the behavior of the pathogen is not predictable. The distribution of the pathogen inside vine plant organs was analyzed through the four growing seasons. The old wood was contaminated throughout the year and constituted a stock inoculum for endophytic contamination of crude sap during the winter and the spring. Despite the fact that most of the young green shoots were contaminated in May, X.ampelinus was not found in green shoots in June and September, refuting the hypothesis of an epiphytic life of the pathogen under natural conditions. Although all plants were entirely contaminated in both vineyards, symptoms were rare and were observed on different plants each year.

Burkholderiaceae↗

PubMedDate not supplied

Multicentre randomised double bind crossover trial on contamination of conventional ties and bow ties in routine obstetric and gynaecological practice.

OBJECTIVE: To assess level of contamination of neckwear worn by gynaecologists and obstetricians during routine working week. DESIGN: Multicentre randomised double blind crossover trial. Participants wore the same conventional ties for three days in one week and bow ties for the same period in second week. SETTING: Two teaching and three district general hospitals in the midlands, Wales, and north England. SUBJECTS: 15 registrars and senior registrars. INTERVENTIONS: A swab soaked in sterile saline was taken from specific area on ties at end of first and third working days and sent in transport medium for culture on chocolatised blood and MacConkey agar for 48 hours. MAIN OUTCOME MEASURES: Level of bacteriological growth assessed semiquantitatively (0 for no contamination; for heavy contamination) after swabs had been cultured. At end of study the participants completed a questionnaire to assess their attitude toward wearing different types of necktie. RESULTS: 12 doctors (80%) completed the study. Although bow ties were significantly less contaminated at end of first working day (z = -2.354, p = 0.019), this difference was not maintained; there was no difference in level of contamination on third day. Level of contamination did not increase between first and third day of wearing the same garment. One of the 10 doctors who returned the questionnaire found the bow tie very uncomfortable. All participants would consider wearing a bow tie if it proved to be less contaminated than a conventional tie. CONCLUSIONS: Although a significant difference in contamination was established between conventional and bow ties on first day of study, this difference was not confirmed on third day and there is unlikely to be any real association between tie type and bacterial contamination. Because of its negative image and difficulty to tie, the bow tie will probably remain a minority fashion.

Attitude of Health Personnel↗

PubMedDate not supplied

Trace element contamination of total parenteral nutrition. 1. Contribution of component solutions.

BACKGROUND: Trace elements have been shown to contaminate total parenteral nutrition (TPN) solutions. METHODS: This study used the multi-elemental technology of inductively coupled plasma-mass spectrometry to demonstrate the extent to which trace elements were present in amounts above (ie, as contaminants) or below expected levels in eight TPN component solutions. RESULTS: Of the 66 trace elements scanned, there were 12 trace element contaminants in amounts >1 microg/L (zinc, copper, manganese, chromium, selenium, boron, aluminum, titanium, barium, vanadium, arsenic, and strontium) in the eight component solutions studied. Trace element contaminants were present in all solutions, and different trace elements contaminated the solutions at various concentrations. Component solutions of amino acid, potassium chloride, calcium gluconate, and sodium chloride contained the greatest numbers of trace element contaminants, whereas the lowest numbers were present in sterile water and magnesium sulfate. Interlot and intermanufacturer variations were apparent. Measured concentrations of trace elements in the multi-trace element additive solution also were higher than the labeled values. A comparison of the amounts of contaminated trace elements delivered by a typical TPN mixture relative to the amounts typically absorbed by the gastrointestinal tract indicates that the inadvertent delivery of trace elements from contaminated TPN solutions may be substantial. CONCLUSIONS: All eight components tested were contaminated with trace elements not intended to be present in the product, and similarly, the multi-trace element component contained trace elements either above or below that which the label claimed.

Drug Contamination↗

PubMed2005

The potential impact of climate on human exposure to contaminants in the Arctic.

Many northern indigenous populations are exposed to elevated concentrations of contaminants through traditional food and many of these contaminants come from regions exterior to the Arctic. Global contaminant pathways include the atmosphere, ocean currents, and river outflow, all of which are affected by climate. In addition to these pathways, precipitation, animal availability, UV radiation, cryosphere degradation and human industrial activities in the North are also affected by climate change. The processes governing contaminant behaviour in both the physical and biological environment are complex and therefore, in order to understand how climate change will affect the exposure of northern people to contaminants, we must have a better understanding of the processes that influence how contaminants behave in the Arctic environment. Furthermore, to predict changes in contaminant levels, we need to first have a good understanding of current contaminant levels in the Arctic environment, biota and human populations. For this reason, it is critical that both spatial and temporal trends in contaminant levels are monitored in the environment, biota and human populations from all the Arctic regions.

Animals↗

PubMed1991

Operator-induced contamination in cell culture systems.

Operator-induced biological contamination in cell cultures is a multifaceted problem involving the unexpected introduction of other animal cells, microbial and viral contaminants. Detailed studies on animal cell cross contaminations have been performed and published. The frequency of detection of problem cultures has been as high as 36% for one service performed in the USA, with interspecific cross contamination accounting for 25% and human intraspecific contamination representing 11%. Awareness of the potential of this problem plus the application of several characterizations are key factors for its control. For example, fluorescent antibody staining, isoenzyme analyses, cytogenetic evaluations and DNA fingerprinting using molecular probes are needed for quality assurance on master seed stocks. Detection of microbial contamination is relatively straightforward, but the prevalence of mycoplasmal infections in cell cultures used in general research is still a significant problem. Detection services report frequencies of infection varying from 10% upwards, depending upon the country and laboratory of origin. The utilization of prescreened reagents and antibiotic-free cultivation, plus the application of improved procedures, such as fluorescent dyes and molecular probes for detection, provide effective means of avoiding mycoplasma infection and facilitating control. For many viruses, the presence of mycoplasma reduces immunoreactivity, suppresses transcriptase and other enzyme activities, reverses viral neutralization etc. The introduction of viral contaminants into cell cultures is perhaps the most problematic, especially where no cytopathic effect is produced. Few cases are documented where technicians infected with specific viruses have introduced these unwittingly into cultures in their care. The potential exists, however, as reports have appeared documenting the considerable stability of rhinoviruses, respiratory syncytial virus, rotaviruses and others, in aerosols on workers' hands and safety hood surfaces. The infection of cell cultures via other contaminated cells or reagents such as sera is a related problem. In this regard, the infection of transplantable tumor cell lines with lymphocytic choriomeningitis virus from host animals led to an outbreak of the disease in medical center personnel. Similar infection of rat cell lines exposed to animals harboring hantaviruses has been reported. Technical staff in US government laboratories have been infected with human immunodeficiency virus produced in cultured cells. Such serious public health hazards warrant repeated emphasis. The use of multiple cell lines in a given laboratory, including cultures known to be virally infected, compounds the problems and necessitates application of preventive methods both to avoid cross-infections and to document freedom from contamination.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Identification, location and analysis of contamination problems associated with cell/tissue preparation, stimulation and measurement techniques.

Any time a cell suspension or tissue sample is handled, chemically treated and prepared or measured with electrical or electrochemical probes, some level of contamination will occur. Often, the level and type of contamination can lead to serious misinterpretation of experimental results. A number of specific contamination problems have been consistently observed with certain preparation, stimulation and measurement techniques utilized in cell biology, histology, microbiology and pharmacology. Four of the more serious problems that can occur are as follows: 1) contamination from media constituents; 2) contamination of cell suspensions and tissue from constituents and impurities in glassware; 3) fungal contamination of cell and tissue samples from glutaraldehyde fixatives and 4) contamination of cell suspensions and tissues from metal ions that have dissociated from electrodes and probes. A scanning electron microscope/energy dispersive x-ray (SEM/EDX) system can provide the resolution, sensitivity and analytical capability to detect these contaminants in a variety of locations, identify them and determine their origin. Thus, erroneous conclusions from data that have been affected by various contaminants can be minimized or prevented if the problems are identified and located.

Biological Assay↗

PubMed1979

Adventitious contamination of intravenous admixtures during sterility testing.

The extent to which contamination of intravenous fluids measured by inhospital sterility-testing may be due to adventitious contamination (i.e., contamination introduced during the sterility-testing procedure) was studied. All one-liter admixtures prepared during a three-day period in a busy centralized i.v. admixture service were studied. Samples of i.v. admixtures were cultured before and after administration by direct ioculation or by culturing the membrane through which the admixture was filtered. Samples of similarly cultured large-volume parenterals served as controls. Contamination rates for control and admixture samples were not significantly different (p = 0.23). Of 10 control and test (admixture) solutions showing contamination before administration, only one test solution again showed contamination after administration but this was with a different microbe. The results suggest that adventitious contamination during sampling/culturing procedures is a component of, and possibly a dominant factor in, the contamination rates detected by inhospital sterility tests. Combined with infection surveillance, sterility tests may be of value when infections are possibly related to admixture contamination.

Bacteria↗

PubMed1993

Contamination of transplantable tumors, cell lines, and monoclonal antibodies with rodent viruses.

Different biological materials were tested for murine viral contamination by using the mouse/rat antibody production test. Of 297 tumors examined, 75 (25.3%) were contaminated. Considerable differences in the contamination rate became evident when transplantable tumors from in vitro and from in vivo passages were compared. Of 186 tumors that had been propagated in animals, 36.6% were positive, whereas only 7 of 111 (6.3%) tumors propagated in vitro were contaminated. The highest rate of contamination was detected in mouse tumors. Testing of 135 specimens of mouse origin revealed 46.7% were contaminated, and 57 (70.4%) of 81 samples propagated in mice were positive for murine viruses. Moreover, 6.7% of 90 human tumors that had been passaged in athymic nude mice and 3.5% of 57 rat tumors were positive. Lymphocytic choriomeningitis virus was detected in 4 of 14 hamster tumors. The most frequent contaminant was lactic dehydrogenase elevating virus followed by reovirus 3, lymphocytic choriomeningitis virus, minute virus of mice, mouse hepatitis virus, rat coronaviruses, Kilham rat virus, and Mycoplasma pulmonis. Contamination with reovirus 3 and minute virus of mice was found in 4 (3.7%) of 109 cell lines tested, and 2 of 60 monoclonal antibody preparations or hybridoma cells contained lactic dehydrogenase virus. Contamination with two pathogens was detected in four mouse tumors and in one cell line.

Animals↗

PubMed1997

Monitoring and assessment of dietary exposure to chemical contaminants.

The results of the Global Environment Monitoring System/Food Contamination Monitoring and Assessment Programme (GEMS/Food) and other monitoring programmes for priority contaminants in the diet, including lead, cadmium, mercury, polychlorinated biphenyls, organochlorine and organophosphorus pesticide residues and aflatoxin, are presented. These results are assessed with respect to established acceptable or tolerable intakes for these contaminants. While the assessments generally confirm the effectiveness of government efforts to prevent or reduce food contamination in industrialized countries, better exposure estimates for infants and children and other vulnerable groups should be calculated. In developing countries, little reliable information is available on the occurrence of food contamination. Without such information, the health of hundreds of millions of people may be threatened. For these countries, and especially those that employ older agricultural and industrial technologies, basic food contamination monitoring and assessment programmes should be established for at least those contaminants of priority concern. These programmes form an essential basis for developing effective intervention strategies and for efficient management of health and environment resources. In all countries, accidental and sporadic contamination is an ever present danger and continual vigilance is necessary to protect public health. All countries should identify institutions with the analytical capability to support epidemiological investigations of outbreaks of disease that may be associated with consumption of chemically contaminated food. All countries should participate in GEMS/Food to promote health-oriented, population-based monitoring at the national level.

Diet Surveys↗

PubMed1992

The impact of the ISIS experiment order on spatial contamination.

When performing volume-localized spectroscopy measurements, the amount of spatial contamination is an important quality criterion. With the ISIS localization technique contamination cannot only arise from the transition regions around the volume of interest, but also from remote regions of the sample. The latter contamination component is a consequence of inhomogeneous excitation pulses, if short repetition times TR are used. Its severity depends both on the order of the eight phase cycling experiments needed for an ISIS measurement, and on the ratio TR/T1. Here it is theoretically discussed from which regions of the sample contamination can arise for a specific phase cycling order. For the worst orders the contaminating regions are almost three times as large as for the optimal orders. The ratio for the effectively measured contamination, however, can be moderated in real experiments, because cancellation effects occur due to the phase distribution of the contaminating signals. 31P phantom experiments clearly demonstrate that contamination is present even if adiabatic excitation pulses are applied and that spatial contamination can be reduced to about a third by an optimal choice of the phase cycling order.

Brain↗

PubMed2006

Use of models to assess the reduction in contamination of water bodies by agricultural pesticides through the implementation of policy instruments: A case study of the Voluntary Initiative in the UK.

Through normal agricultural use, pesticides may reach environmental water bodies via several routes of entry. Various policies and initiatives exist to reduce the effects of pesticides in the environment. One such initiative in place in the UK is the Voluntary Initiative (VI). The VI is a voluntary scheme put forward by the Crop Protection Association with other crop protection and farming organisations to reduce the environmental impacts of pesticides. Mathematical models of pesticide fate can usefully be applied to examine the impact of factors influencing the contamination of water bodies by pesticides. The work reported here used water quality models to examine how changes in farmer behaviour could potentially impact pesticide contamination of environmental water bodies. As far as possible, uncalibrated, standard regulatory models were used. Where suitable models were not available, simple models were defined for the purposes of the study and calibrated using literature data. Scenarios were developed to represent different standards of practice with respect to pesticide user behaviour. The development of these scenarios was guided by the Crop Protection Management Plan (CPMP) aspect of the VI. A framework for the use of modelling in the evaluation of the VI is proposed. The results of the modelling study suggest that, in several areas, widespread adoption of the measures proposed in the VI could lead to reductions in pesticide contamination of environmental water bodies. These areas include pesticide contamination from farmyards, spray drift and field runoff. In other areas (including pesticide leaching to groundwater and contamination of surface water from field drains) the benefits that may potentially be gained from the VI are less clear. A framework to evaluate the VI should take into consideration the following aspects: (1) groundwater is more at risk when there is a combination of leachable compounds, vulnerable soils, shallow groundwater and high product usage; (2) surface water contamination from drains is most likely when heavy rain falls soon after application, the soils are vulnerable and product usage is high; (3) surface water contamination from drift is most likely when the distance between the spray boom and water body is small and product usage is high; (4) surface water contamination from farmyards is dependent on the nature of the farmyard surface, the competence of the spray operator and the level of product usage. Any policy or initiative to reduce pesticide contamination should be measured against farmer behaviour in these areas.

Agriculture↗

PubMed2006

Ecological risk assessment of contaminated soil.

This review has described three cases of ecological risk assessment. The cases include two heavy metals (Cu and Zn) and an anthropogenic organic chemical (DDT). It concludes that there are at least two major constraints hampering the use of laboratory tests to predict effects under natural field conditions. One key issue is bioavailability, and another is suboptimal conditions or multiple stresses in the field such as climatic stress (drought, frost), predators, competition, or food shortage. On the basis of the presented case studies, it was possible to answer three essential questions often raised in connection to ecological risk assessment of contaminated sites. 1. To what extend does soil screening level (SSL) estimate the risk? The SSL are generally derived at levels corresponding to the lowest observed effect levels in laboratory studies, which often is close to the background levels found in many soils. In the cases of zinc and especially DDT, the SSL seemed quite conservative, whereas for copper they resemble the level at which changes in the community structure of soil microarthropods and the plant community have been observed at contaminated sites. The SSL correspond as a whole relatively well with concentrations where no effects or only minor effects were observed in controlled field studies. However, large variation in field surveys can often make it difficult to conclude to what extent the SSL corresponded to no-effect levels in the field. 2. Do bioassays represent a more realistic risk estimate? Here, there is no firm conclusion. The zinc study in UK showed a better relationship between the outcome of ex situ bioassays and field observations than the SSL. The latter overestimated the risk compared to field observations. However, this would be species dependent, as the sensitivity to metals may vary considerably between recognized test species, even within the same group of organisms, such as Folsomia candida and Folsomia fimetaria or Eisenia fetida and Lumbricus sp. Furthermore, it was demonstrated that bioassays were not useful for predicting general species diversity in the field as they are strongly influenced by natural variation and other factors not related to contamination. In the case of copper, bioassays with springtails and black bindweed seemed to underestimate the risk compared to the Cu concentrations at which significant changes in the community structure of soil microarthropods and plants have been observed at the contaminated site, and this was also the case for the DDT-contaminated soils. Here, bioassays with DDT-contaminated soils showed generally very low toxicity, with EC10 values considerably higher than the levels where clear effects on single species as well as community structure have been detected in the present field study. 3. Is it possible to make sound field surveys or do we lack suitable reference situations? Large natural variation caused by other factors than contaminants were observed in most cases, and this may have particularly hampered the conclusions made in the field surveys. These factors included pH, private and military traffic, age of vegetation, shading effects, and variations in light insensitivity as well as quantity and quality of organic matter. It was therefore concluded that field studies should always be interpreted in concert with similar data from a reference situation. Conclusions should therefore be made with caution in situations where important soil conditions vary between control plots and the contaminated sites. The cases also showed that indices focusing on species richness were unreliable. Estimates of evenness or dominance were recommended instead, and most authors concluded that multivariate analysis of community structure was a sensitive and useful method superior to single-species field data. This review concludes that there is a need for a tiered approach in ecological risk assessment of contaminated soils. Generic soil screening levels are needed as a first tier. Higher tiers of ecological risk assessment should, however, contain some kind of site-specific assessment. It is furthermore important to organize the various studies in a framework or decision support system that is transparent and useful for all stakeholders. A weight of evidence approach may be an obvious choice to deal with these uncertainties. The TRIAD approach, which incorporates and categorizes information in a triangle - chemistry, toxicology, and ecology - is an appropriate tool for handling conceptual uncertainties.

Animals↗

PubMed2002

Ecological benefits of contaminated sediment remediation.

Contaminated sediment has been identified as a source of ecological impacts in marine and freshwater systems throughout the world, and the importance of the contaminated sediment management issue continues to increase in all industrialized countries. In many areas, dredging or removal of sediments contaminated with nutrients, metals, oxygen-demanding substances, and persistent toxic organic chemicals has been employed as a form of environmental remediation. In most situations, however, the documentation of the sediment problem has not been quantitatively coupled to ecological impairments. In addition, the lack of long-term, postactivity research and monitoring for most projects has impeded a better understanding of the ecological significance of sediment contamination. Establishing quantitatively the ecological significance of sediment-associated contamination in any area is a difficult time- and resource-consuming exercise. It is, however, absolutely essential that it be done. Such documentation will likely be used as the justification for remedial and rehabilitative action(s) and also as the rationale for proposing when intervention is necessary in one place but not another. Bounding the degree of ecological impact (at least semiquantitatively) provides for realistic expectations for improvement if sediment remediation is to be pursued. It should also provide essential information on linkages that could be used in rehabilitating other ecosystem components such as fish or wildlife habitat. The lack of information coupling contaminated sediment to specific ecological impairments has, in many instances, precluded a clear estimate of how much sediment requires action to be taken, why, and what improvements can be expected to existing impairment(s) over time. Also, it has likely resulted in either a delay in remedial action or abandonment of the option altogether. A clear understanding of ecological links not only provides adequate justification for a cleanup program but also represents a principal consideration in the adoption of nonintervention, alternative strategies. In developing this understanding, it is important to know not only the existing degree of ecological impairment associated with sediment contaminants but also the circumstances under which those relationships and impacts might change (i.e., contaminants become more available and more detrimental). Because contaminated sediment remediation often costs millions of dollars per area, adequate assessment, prediction, and monitoring of recovery would seem obvious. However, experience has shown that this is not always the case, particularly for prediction and monitoring of ecological recovery. This scenario would never happen in the business world and should not occur in the environmental management field.

Animals↗

PubMed2001

Use of semipermeable membrane devices (SPMDs). Determination of bioavailable, organic, waterborne contaminants in the industrial region of Bitterfeld, Saxony-Anhalt, Germany.

Triolein-containing semipermeable membrane devices (SPMDs) were employed as passive samplers to provide data on the bioavailable fraction of organic, waterborne, organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polynuclear aromatic hydrocarbons (PAHs) in streams flowing through a highly polluted industrial area of Bitterfeld in Saxony-Anhalt, Germany. The contamination of the region with organic pollutants originates in wastewater effluents from the chemical industry, from over one-hundred years of lignite exploitation, and from chemical waste dumps. The main objective was to characterise time-integrated levels of dissolved contaminants, to use them for identification of spatial trends of contamination, and their relationship to potential pollution sources. SPMDs were deployed for 43 days in the summer of 1998 at four sampling sites. The total concentration of pollutants at sampling sites was found to range from a low of 0.8 microgram/SPMD to 25 micrograms/SPMD for PAHs, and from 0.4 microgram/SPMD to 22 micrograms/SPMD for OCPs, respectively. None of the selected PCB congeners was present at quantifiable levels at any sampling site. A point source of water pollution with OCPs and PAHs was identified in the river system considering the total contaminant concentrations and the distribution of individual compounds accumulated by SPMDs at different sampling sites. SPMD-data was also used to estimate average ambient water concentrations of the contaminants at each field site and compared with concentrations measured in bulk water extracts. The truly dissolved or bioavailable portion of contaminants at different sampling sites ranged from 4% to 86% for the PAHs, and from 8% to 18% for the OCPs included in the estimation. The fraction of individual compounds found in the freely dissolved form can be attributed to the range of their hydrophobicity. In comparison with liquid/liquid extraction of water samples, the SPMD method is more suitable for an assessment of the background concentrations of hydrophobic organic contaminants because of substantially lower method quantification limits. Moreover, contaminant residues sequestered by the SPMDs represent an estimation of the dissolved or readily bioavailable concentration of hydrophobic contaminants in water, which is not provided by most analytical approaches.

Environmental Monitoring↗

PubMed2003

Toxicity of lead-contaminated sediment to mute swans.

Most ecotoxicological risk assessments of wildlife emphasize contaminant exposure through ingestion of food and water. However, the role of incidental ingestion of sediment-bound contaminants has not been adequately appreciated in these assessments. This study evaluates the toxicological consequences of contamination of sediments with metals from hard-rock mining and smelting activities. Lead-contaminated sediments collected from the Coeur d'Alene River Basin in Idaho were combined with either a commercial avian maintenance diet or ground rice and fed to captive mute swans (Cygnus olor) for 6 weeks. Experimental treatments consisted of maintenance or rice diets containing 0, 12 (no rice group), or 24% highly contaminated (3,950 microg/g lead) sediment or 24% reference (9.7 microg/g lead) sediment. Although none of the swans died, the group fed a rice diet containing 24% lead-contaminated sediment were the most severely affected, experiencing a 24% decrease in mean body weight, including three birds that became emaciated. All birds in this treatment group had nephrosis; abnormally dark, viscous bile; and significant (p <or= 0.05) reductions in hematocrit and hemoglobin concentrations compared to their pretreatment levels. This group also had the greatest mean concentrations of lead in blood (3.2 microg/g), brain (2.2 microg/g), and liver (8.5 microg/g). These birds had significant (alpha = 0.05) increases in mean plasma alanine aminotransferase activity, cholesterol, and uric acid concentrations and decreased plasma triglyceride concentrations compared to all other treatment groups. After 14 days of exposure, mean protoporphyrin concentrations increased substantially, and mean delta-aminolevulinic acid dehydratase activity decreased by more than 95% in all groups fed diets containing highly contaminated sediments. All swans fed diets that contained 24% lead-contaminated sediment had renal acid-fast intranuclear inclusion bodies, which are diagnostic of lead poisoning in waterfowl. Body weight and hematocrit and hemoglobin concentrations in swans on control (no sediment) and reference (uncontaminated) sediment diets remained unchanged. These data provide evidence that mute swans consuming environmentally relevant concentrations of Coeur d'Alene River Basin sediment developed severe sublethal lead poisoning. Furthermore, toxic effects were more pronounced when the birds were fed lead-contaminated sediment combined with rice, which closely resembles the diet of swans in the wild.

Animal Feed↗

PubMed2006

Rapid intrinsic biodegradation of benzene, toluene, and xylenes at the boundary of a gasoline-contaminated plume under natural attenuation.

A groundwater plume contaminated with gasoline constituents [mainly benzene, toluene, and xylenes (BTX)] had been treated by pumping and aeration for approximately 10 years, and the treatment strategy was recently changed to monitored natural attenuation (MNA). To gain information on the feasibility of using MNA to control the spread of BTX, chemical and microbiological parameters in groundwater samples obtained inside and outside the contaminated plume were measured over the course of 73 weeks. The depletion of electron acceptors (i.e., dissolved oxygen, nitrate, and sulfate) and increase of soluble iron were observed in the contaminated zone. Laboratory incubation tests revealed that groundwater obtained immediately outside the contaminated zone (the boundary zone) exhibited much higher potential for BTX degradation than those in the contaminated zone and in uncontaminated background zones. The boundary zone was a former contaminated area where BTX were no longer detected. Denaturing gradient gel electrophoresis (DGGE) analysis of polymerase chain reaction (PCR)-amplified bacterial 16S rRNA gene fragments revealed that DGGE profiles for groundwater samples obtained from the contaminated zone were clustered together and distinct from those from uncontaminated zones. In addition, unique bacterial rRNA types were observed in the boundary zone. These results indicate that the boundary zone in the contaminant plumes served as a natural barrier for preventing the BTX contamination from spreading out.

Bacteria↗

PubMed1994

Global contamination by persistent organochlorines and their ecotoxicological impact on marine mammals.

The present paper overviews the global contamination by persistent organochlorines and their ecotoxicological implications on marine mammals. The recent pattern of contamination by organochlorine residues in the coastal environment is prominent in tropical regions due to continuous usage in the low-latitude developing countries. The major emission source of organochlorines is probably the tropical belt and large quantities of volatilized contaminants are dispersed through the atmosphere on global terms. Reflecting this, a considerable contamination was observed in open ocean tropical waters as well as in the Arctic and nearby waters. The study of the mass transfer of organochlorines at the air-water interface suggests that the oceanic water bodies, particularly Arctic waters, act as a sink for persistent contaminants. In this regard, the marine mammals, particularly cetaceans, are one of the animal groups receiving high concentrations of persistent organochlorines arising out of a worldwide contamination. They can amplify much greater amounts of toxic contaminants through feeding and also pass them in large quantities from one generation to the next through lactation. Unfortunately, these animals have a smaller capacity for degradation of these contaminants due to the specific mode of cytochrome P-450 enzyme systems. These drug-metabolizing enzyme systems may be related to the possible effects of persistent organochlorines, particularly coplanar PCBs. Furthermore, the residue levels of these contaminants in marine mammals are unlikely to decline in the near future. Considering all these facts, it may be concluded that marine mammals are one of the most vulnerable and possible target organisms with regard to long-term toxicity of hazardous man-made chemicals in the future.

Animals↗