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PubMedDate not supplied

Worldwide survey of fumonisin contamination of corn and corn-based products.

As part of a comprehensive risk assessment study for fumonisins, reliable data on exposure of populations to these dietary toxins must be obtained. To assess the extent of worldwide exposure, the published literature on the contamination of food and feed supplies has been reviewed and supplemented with unpublished material from various international sources. Fumonisin contamination of corn and corn-based products occurs in many countries. Animal mycotoxicoses such as equine leukoencephalomalacia and porcine pulmonary edema are caused by heavily contaminated animal feeds. For example, as much as 330 micrograms/g fumonisin B1 (FB1) has been found in swine feed. Although commercially available refined corn products for human consumption are generally contaminated at levels below 1 microgram/g FB1, individual products in certain countries can reach far higher levels. Health risks associated with consumption of these products depend on the extent to which they are consumed in a varied diet. Home-grown corn in certain rural areas, where it also constitutes the staple diet, can be contaminated at > 100 micrograms/g. Consumption of corn contaminated at these high levels has been associated with a high incidence of esophageal cancer in these areas.

Animal Feed↗

PubMed1995

Bacterial contamination of hospital disinfectants.

A study to determine contamination of diluted disinfectants at different points in preparation and use in 6 Malaysian hospitals was done using the in-use test. A growth of > or = 250 organisms/ml was taken as an indication of contamination. A total of 342 (7.9%) of the 4316 freshly diluted samples collected from disinfectant bottles in the pharmacy were found to be contaminated. The bacterial isolates obtained were Pseudomonas spp. (42.4%), Moraxella spp. (22.0%), Flavobacterium spp. (11.6%) and Enterobacter spp. (4.2%). Three hundred and sixty seven out of 2278 ward stock were contaminated. The isolates were Pseudomonas spp. (48.6%), Moraxella spp. (17.8%), Acinetobacter spp. (8.9%) and Flavobacterium spp. (7.0%). Of the 9265 disinfectants in-use, 1519 (16.4%) were contaminated. Among the organisms isolated were Pseudomonas spp. (44.3%), Bacillus spp. (13.0%), Enterobacter spp. (9.5%) and Acinetobacter spp. (7.3%). The results indicated a high level of contamination of diluted disinfectants prepared in the pharmacy, stored and used in the wards. This gave a high index of suspicion that recommendations for cleaning of disinfectant containers before refilling, handling of diluted stock solutions and using of disinfectants were not closely adhered to. Standard disinfection procedures outlined in the disinfection and sterilization policy by the Ministry of Health should therefore be followed.

Bacteria↗

PubMed1996

Model of multiple exposure to contaminants in monitoring the environmental impact on population health.

The model study is focused on possibilities of comprehensive evaluation of the multiple exposure of humans to selected inorganic contaminants (arsenic, cadmium, lead, zinc) monitored within the subsystems of the monitoring the environmental impact on population health (inhalation and ingestion exposure from air, drinking water and foodstuffs and biological monitoring). The mean daily intake of contaminants of average adults is assessed using the monitoring and literature data. The exposure balance showed that the total intake of individual contaminants studied did not exceed the limit values given by the exposure standards (acceptable daily intake). The highest value of exposure reaching 28% of the limit was reported for cadmium. The prevailing pathway of exposure is ingestion of foodstuffs: more than 95% in all contaminants under study. Information on the intake of contaminants is used as input in a linear multicompartmental model describing their kinetics and retention in the human organism. The results of the model computation are compared with the laboratory data obtained in the biological monitoring of adult urine. The model and monitoring sets of results were found to conform well for cadmium and zinc. For arsenic and lead the model values are roughly one order of magnitude lower than the monitored ones which should be considered as acceptable for the model studies of this type. The model study of contaminant monitoring data processing and evaluation suggests further applications of health risk assessment representing one of the basic outputs of monitoring the environmental impact on population health.

Adult↗

PubMed1997

[Human biomonitoring--studies of arsenic, lead and PCDD/F in inhabitants of a contaminated residential area].

The levels of arsenic in urine, lead in blood, and PCDD/F in blood fat were determined in 12 subjects living in a residential area where the soil was contaminated by arsenic, lead, PCDD/F and other pollutants. Six residents (group I, mean age 56 years) were living on the contaminated site for at least 35 years, and had consumed home-grown vegetables and fruits as well as self-produced animal products (eggs, meat). Six residents (group II, mean age 47 years) had been living on the contaminated site for an average period of 9 years, and had consumed only minor amounts of home-grown vegetables and fruits, but no self-produced animal products. Some of them had skin contact with contaminated soil during excavation and garden work. For comparison, blood and urine samples of subjects living in the same region but not exposed to soil contaminants were investigated for the above mentioned parameters. The reference subjects were selected by age and gender in order to form matched pairs with the exposed subjects. The levels of arsenic in urine and lead in blood did not differ significantly between the residents of the contaminated area and the reference subjects. With regard to PCDD/F in blood fat a significantly increased PCDD/F-body burden was found for the subjects of group I (median: 41.5 pg I-TE/g fat, range: 18.0-54.6 pg I-TE/g fat; reference group, median: 20.3 pg I-TE/g fat, range: 12.2-30.5 pg I-TE/g fat), whereas the subjects of group II had only a moderately, but not significantly increased PCDD/F-body burden (median: 23.4 pg I-TE/g fat, range 13.1-45.8 pg I-TE/g fat) when compared with the reference group (median: 13.9 pg I-TE/g fat, range: 12.1-30.5 pg I-TE/g fat). Increased PCDD/F levels in blood fat seemed to be related mainly to the consumption of self-produced animal products. From the present-day toxicological point of view, none of the subjects examined in this study had a critical body burden of PCDD/F.

Adult↗

PubMed1997

Contamination of diagnostic ophthalmic solutions in primary eye care settings.

Pharmaceutical agents and irrigating solutions are widely used in both optometric and ophthalmologic practices. Contamination of these containers or solutions could possibly pose some risk of infection to a patient. We set out to investigate the possible contamination of a representative sample of these containers in small office practices. Representative bottles of two diagnostic pharmaceutical agents and an irrigating solution were obtained from primary care optometric and ophthalmologic practices in the San Francisco-Oakland Bay area. These bottles were tested to investigate the rate of contamination and to identify the types of microorganisms in the contaminated solutions. Sixty total samples (proparacaine, tropicamide, and an irrigating solution) were randomly cultured, and 11.7% of the samples showed contamination. Pseudomonas cepacia, Staphylococcus epidermidis, Pseudomonas putida, and Streptococcus species were the predominant organisms isolated from the contaminated bottles. In addition, 17 of the original 60 containers were further cultured for investigation of the dried residue particles around the threads of the containers. Of these 17 containers, 13 (76.5%) tested positive for Staphylococcus and Micrococcus species.

Ambulatory Care Facilities↗

PubMed1998

Risk of contamination from air vents during intravenous fluid administration.

The microbial effect of creating air-inlet during intravenous fluid administration in different wards of the University of Calabar Teaching Hospital was studied between May and July, 1997. A total of 123 in-use (test) and 80 unused (control) infusion fluids were studied. Subjects that developed septicaemia following infusion were screened for microbial aetiology. Settle plate cultures were made in all the wards used in the study. Thirty two of in-use infusion fluids (26%) were contaminated, while contamination was not detected among the unused ones. There is a statistically significant relationship in the contamination rate of in-use bags and controls (p < 0.001). Bags with air-vents were more contaminated 27(49.1%) than those with none, five (7.4%). The difference in prevalence of contamination rate by air-vent status was statistically significant (p < 0.001). Gram positive organisms constituted the majority of agents 26(74.3%). Out of seven subjects that received contaminated fluid, four (57.1%) developed septicaemia. It is concluded that creating air-vent for introduction of additives during intravenous fluid administration provides routes of entry for micro-organisms.

Adolescent↗

PubMed1999

Bacterial contamination of the hands of hospital staff during routine patient care.

BACKGROUND: Cross-transmission of microorganisms by the hands of health care workers is considered the main route of spread of nosocomial infections. OBJECTIVE: To study the process of bacterial contamination of health care workers' hands during routine patient care in a large teaching hospital. METHODS: Structured observations of 417 episodes of care were conducted by trained external observers (S.T. and V.S.). Each observation period started after a hand-cleansing procedure and ended when the health care worker proceeded to clean his or her hands or at the end of a coherent episode of care. At the end of each period of observation, an imprint of the 5 fingertips of the dominant hand was taken and bacterial colony counts were quantified. Regression methods were used to model the intensity of bacterial contamination as a function of method of hand cleansing, use of gloves during patient care, duration and type of care, and hospital ward. RESULTS: Bacterial contamination increased linearly with time on ungloved hands during patient care (average, 16 colony-forming units [CFUs] per minute; 95% confidence interval, 11-21 CFUs per minute). Patient care activities independently (P<.05 for all) associated with higher contamination levels were direct patient contact, respiratory care, handling of body fluid secretions, and rupture in the sequence of patient care. Contamination levels varied with hospital location; the medical rehabilitation ward had higher levels (49 CFUs; P=.03) than did other wards. Finally, simple hand washing before patient care, without hand antisepsis, was also associated with higher colony counts (52 CFUs; P=.03). CONCLUSIONS: The duration and type of patient care affect hand contamination. Furthermore, because hand antisepsis was superior to hand washing, intervention trials should explore the role of systematic hand antisepsis as a cornerstone of infection control to reduce cross-transmission in hospitals.

Bacteria↗

PubMed1983

Fungal contamination in organ culture.

Fungal contamination of organ-cultured corneas was studied retrospectively. Over a 3 1/2-year period, 5.2% of 696 corneas became contaminated by fungi in organ culture. The average length of time for fungal contamination to occur in organ culture was 11 days. The most frequent contaminating fungi were those of the Candida species. In addition to previously identified risk factors for donor cornea contamination, those corneas from donors given mechanical respiratory assistance at the time of death, those corneas with long postmortem times, and those corneas with positive postwash cultures were identified as being at higher risk for fungal contamination in organ culture.

Cornea↗

PubMed1976

Influence of operating room surface contamination on surgical wounds: a prospective study.

The influence of operating room contamination on wound infection rates in clean, clean-contaminated, contaminated, and septid procedures was studied by a prospective randomized study of 2,020 surgical wounds. Operating room surface contamination was assessed by the RODAC bacterial plate method. Control rooms uniformly received Wet-Vac cleaning between operations. Experimental rooms were not cleaned between consecutive clean operations, but were cleaned after contaminated operations. The difference in surface contamination between groups of experimental and control rooms was found to be significant at the P less than .05 level. Patients operated on in experimental and control rooms were followed up postoperatively to assess whether they experienced wound infection. No statistically significant differences in wound infection rates were found between experimental and control room operations as total groups, clean procedures, or operations of long duration.

Bacteria↗

PubMed2006

Toward complete laser ablation of melanoma contaminant cells in a co-culture outgrowth model via image cytometry.

BACKGROUND: Contaminant cancer cells in autologous transplant tissue can cause relapse and the rates are unknown. A method capable of removing all contaminant cells with a high probability detected by cytomic analyses would be useful. Neither 100% cell purging nor techniques for measuring the probability of success have been developed. Here, we report a method for removing 100% of the cells under ideal staining conditions and quantify the probability of success. METHODS: Laser ablation was combined with previously reported automated microscopy to purge contaminant cells and evaluate 100% ablation in a co-culture model of prestained mouse melanoma cells mixed with mouse NIH-3T3 cells. Melanoma passage efficiency was measured by: (1) micropipetting single cells into microtiter wells and (2) ablating all but one melanoma cell in co-cultures. RESULTS: (74 +/- 5)% of single melanoma cells pipetted into microtiter plate wells divided at least once. With ablation of all but one contaminant cell in co-cultures, melanoma dominated in (62 +/- 8)% cultures in 21 days. With 100% ablation in six additional experiments, no melanoma outgrowth was observed, giving a >99.1% probability that all contaminant melanoma cells were purged. CONCLUSIONS: We successfully demonstrated a model for complete ablation within a defined probability using automated high-content image cytometry with ideal staining conditions. The results show that the instrumentation is capable of delivering 100% ablation at a defined probability and establishes the basis for further studies with clinical models wherein pretherapeutic cytomic analyses of unique cellular expression and/or morphological characteristics will be key for contaminant cancer cell identification.

Animals↗

PubMed2005

Ecotoxicological evaluation of diesel-contaminated soil before and after a bioremediation process.

Evaluation of contaminated sites is usually performed by chemical analysis of pollutants in soil. This is not enough either to evaluate the environmental risk of contaminated soil nor to evaluate the efficiency of soil cleanup techniques. Information on the bioavailability of complex mixtures of xenobiotics and degradation products cannot be totally provided by chemical analytical data, but results from bioassays can integrate the effects of pollutants in complex mixtures. In the preservation of human health and environment quality, it is important to assess the ecotoxicological effects of contaminated soils to obtain a better evaluation of the healthiness of this system. The monitoring of a diesel-contaminated soil and the evaluation of a bioremediation technique conducted on a microcosm scale were performed by a battery of ecotoxicological tests including phytotoxicity, Daphnia magna, and nematode assays. In this study we biostimulated the native microflora of soil contaminated with diesel by adding nutrients and crop residue (corn straw) as a bulking agent and as a source of microorganisms and nutrients; in addition, moisture was adjusted to enhance diesel removal. The bioremediation process efficiency was evaluated directly by an innovative, simple phytotoxicity test system and the diesel extracts by Daphnia magna and nematode assays. Contaminated soil samples were revealed to have toxic effects on seed germination, seedling growth, and Daphnia survival. After biostimulation, the diesel concentration was reduced by 50.6%, and the soil samples showed a significant reduction in phytotoxicity (9%-15%) and Daphnia assays (3-fold), confirming the effectiveness of the bioremediation process. Results from our microcosm study suggest that in addition to the evaluation of the bioremediation processes efficiency, toxicity testing is different with organisms representative of diverse phylogenic levels. The integration of analytical, toxicological and bioremediation data is necessary to properly assess the ecological risk of bioremediation processes.

Animals↗

PubMed1997

Application of multiple bioindicators to differentiate spatial and temporal variability from the effects of contaminant exposure on fish.

Bioindicators of fish health were measured from 1989 through 1994 in populations of redbreast sunfish (Lepomis auritus) at three sites within a stream receiving inputs of mixed contaminants from an industrial facility, and at two reference sites. Bioindicator responses differed for fish from contaminated and reference sites throughout the study period, but temporal trends at contaminated sites reflected improved water quality associated with pollution-control efforts. Temporal variability unrelated to contaminant exposure strongly influenced the response of bioindicators at both reference and contaminated sites, but spatial variability rarely influenced these responses. Temporal variability was less influential on slower responding indicators at higher levels of biological organization. The diverse response characteristics of indicators increased the ability to differentiate natural from anthropogenic sources of variability. Integrated bioindicator responses were compared among site-year groups by multivariate canonical analysis. The primary canonical variable, associated with differences in growth, exhibited trends consistent with the timing of pollution-control efforts. Two indicators of contaminant exposure (7-ethoxyresorufin O-deethylase activity and polychlorinated biphenyls in fish muscle) also exhibited trends consistent with the timing of pollution-control efforts, but the likelihood of possible mechanistic linkages cannot be assessed with available data.

Animals↗

PubMed2002

Responses of microbial activity and decomposer organisms to contamination in microcosms containing coniferous forest soil.

Soil respiration from microcosms contaminated with pentachlorophenol, 2-ethanolhexanoate, creosote, CuSO4, and benomyl was measured in order to evaluate usefulness of soil microcosms and microbial respiration rate monitoring as a toxicity test in soils with high organic matter content. Coniferous forest soil and its organisms were used as test objects. In addition, how a short-term low temperature period including frost affects respiration dynamics in stressed soils was studied, i.e., whether contaminants reduce resistance of the community to other (also natural) stresses. In addition, at the end of the experiment, effects of contaminants on faunal and microbial community structures were analyzed. Soil respiration measurements from the microcosms appeared to be a sensitive parameter for testing community-level effects of chemicals in the soil with high organic matter content. An 84-day exposure had acute effects, long-term effects, delaying effects, and total recovery of community respiration. Direct negative and indirect positive effects of chemical contamination on the community of soil organisms were found. Responses to contamination of soil respiration rate and structure of the soil community were parallel. Addition of pentachlorophenol, 2-ethanolhexane, and Cu into the soil reduced frost resistance of the decomposer community. It was concluded that soil respiration monitoring of artificially contaminated soil microcosms seems to be a useful tool for testing community-level toxic effects of chemicals.

Antidotes↗

PubMed1999

Environmental contaminants and the prevalence of hemic neoplasia (leukemia) in the common mussel (Mytilus edulis complex) from Puget Sound, Washington, U.S.A.

The relationship between hemic neoplasia, a blood cell disorder in bivalve molluscs, and chemical contaminants was evaluated in the common mussel (Mytilus edulis complex). Hemic neoplasia (HN) is endemic to mussel populations in Puget Sound. The prevalence of hemic neoplasia ranged from 0 to 30% in mussels from nine sites in Puget Sound, Washington. Organic chemical contamination in sediment from these sites range from 0.1 to 64.0 ppm of polycyclic aromatic hydrocarbons (PAHs) and 0.07 to 0.50 ppm chlorinated hydrocarbons. No relationship between the body burden of environmental contaminants and the prevalence of HN in mussels was identified. To evaluate the short-term ability of chemical contaminants to induce HN in mussels, mussels, from a site where mussels were previously determined to be HN free, were fed microencapsulated PAHs (composed of a mixture of phenanthrene, flouranthene, and benzo[a]pyrene) or PCBs (Aroclor 1254) and the prevalence of HN was assessed after 30 days of exposure. Although an apparent increase in HN prevalence (20 to 30%) was observed in all treatments groups except the untreated controls, no significant difference in the prevalence of HN was observed between the control group of mussels fed corn oil (vehicle) and mussels fed either PAHs or PCBs in corn oil. A long-term (180-day) exposure study was conducted to evaluate the influence of PAHs or PCBs in modulating the prevalence of HN in a mussel population already exhibiting a moderate HN prevalence. Mussels, from a site where mussels were previously determined to exhibit a background prevalence of HN, fed microencapsulated PAHs, PCBs, and corn oil (vehicle) over a long time period (180 days), revealed an apparent increased prevalence of HN (30 to 40%) above the low levels (20%) initially present. However, no significant difference in the prevalence of HN was observed between the control group of mussels fed corn oil (vehicle) and mussels fed either PAHs or PCBs in corn oil. Although chemical contaminants have been proposed as a modulating factor in the development and promotion of HN in bivalve molluscs from environmentally stressed and degraded habitats, we find no evidence that chemical contaminants induce or promote the development of HN in the mussel M. edulis complex.

Animals↗

PubMed1997

Health risk assessment of drinking water contaminants in Canada: the applicability of mixture risk assessment methods.

The objectives of this article are: (i) to review the current approaches of Health Canada to the risk assessment of drinking water contaminants, and (ii) to examine the applicability of mixture risk assessment methods to drinking water contaminants. Health Canada's current approaches to drinking water risk assessment, like those of many regulatory agencies, focus almost solely on the effects of individual chemicals. As such, no formal method is currently used for developing mixtures guidelines or for modifying guidelines of individual chemicals to account for the possibility of the occurrence of interactions (supraadditive or infraadditive). Recent interest in the risk assessment of mixtures, at least in part, stems from concerns over the potential health risks of mixtures of very commonly occurring compounds in Canadian drinking water supplies, namely the disinfection by-products. Before any mixtures methods can be considered for incorporation into Health Canada's current approaches to the risk assessment of drinking water contaminants, it is essential to consider the limitations and data requirements of the various mixture risk assessment methods (i.e., whole mixture approach, similar mixture approach, components-based approaches, interactions-based assessment). Among the existing mixture risk assessment methods, the components-based and interactions-based approaches could be applicable to drinking water contaminants. Specifically, among the components-based approaches, dose-addition, response-addition, and the toxic equivalency factor approaches are the most applicable ones for drinking water contaminants. Until an interactions-based, mechanistic risk assessment approach (e.g., physiological model-based approach) becomes available for routine use, the components-based approaches remain the default methods for consideration. Progress in the development and validation of an interactions-based risk assessment methodology should facilitate a more realistic assessment of risk due to drinking water contaminants without increasing the levels of uncertainty in risk estimates above those associated with existing single-chemical methods.

Canada↗

PubMed2002

Health cancer risk assessment for arsenic exposure in potentially contaminated areas by fertilizer plants: a possible regulatory approach applied to a case study in Moscow region-Russia.

At present, fertilizer industry plants are considered as a potential source of soil contamination in Russia. Therefore health risk assessment should be pursued in Russian fertilizer plant areas, but unfortunately risk assessment methodology for contaminated sites does not have yet a regulatory value in Russia. In this paper a possible and intentionally simple regulatory approach for health cancer risk assessment at phosphogypsum waste-storing potentially contaminated sites is presented. The proposed approach is applied to a potential contaminated area located in the Moscow river (Moscow Region) protective zone. At this case-study area, arsenic has been chosen as a contaminant indicator, according to the proposed selection procedure. For estimating the human exposure to arsenic through various pathways the original McKone & Daniels '91 model has been adapted. As a specific result of the risk assessment for the case-study area, it has been shown that arsenic exposure pathways (in risk-ranking order) "ingestion of agricultural products," "groundwater uptake," "dermal contact," and "soil ingestion" pose a significant health risk. From a general point of view, the proposed and applied health risk assessment approach could give some contribution (for comparison and discussion) for policies on contaminated soils to other countries. In this perspective, the paper expressly considers the current Italian regulative situation concerning restricted use of risk analysis and concerning soil quality for agricultural land use.

Arsenic↗

PubMed1995

Measurements of environmental lead contamination and human exposure.

The importance of accurate measurements of environmental lead exposure and toxicity is substantiated by analyses documenting the global contamination of the biosphere with industrial lead and the pervasiveness of measurable lead toxicity in human populations. Those data demonstrating environmental lead contamination and toxicity have, in part, led to regulations that limit the amount of lead in some products (e.g., paint, solder, and gasolines) in many industrialized countries. These regulations have resulted in a substantial reduction in some lead discharges to the environment. In spite of these reductions, current environmental lead levels are still often more than 10-fold, and sometimes more than 10,000-fold, higher than natural levels. Further, environmental lead concentrations are expected to remain elevated for a protracted period due to continued emissions of relatively large amounts of industrial lead to the environment and the persistence of contaminant lead in the environment. Discharges of contaminant lead have resulted in increases in organism and human lead levels comparable to increases documented in environmental matrices, as indicated by a recent estimate of the natural level of lead in blood of preindustrial humans (0.016 microgram/dL or 0.8 nM). This estimate is 175-fold lower than average blood lead levels in the United States (2.8 micrograms/dL or 140 nM) and 600-fold lower than the recently (1991) revised Centers for Disease Control (CDC) action level of concern for early toxic effects in children (10 micrograms/dL or 480 nM). The significance of these comparisons to public health is corroborated by numerous studies suggesting that there may be no lower threshold for sublethal toxicity in contemporary (i.e., lead-contaminated) humans. Those data also indicate that environmental lead concentrations that were previously considered innocuous may be deleterious to human health. It is apparent that the extent of sublethal lead toxicity in humans may be best addressed by studies that consider control populations possessing natural (i.e., preindustrial) lead burdens, as well as state-of-the-art, trace-metal-clean techniques and advanced instrumentation. Trace-metal-clean techniques are required to prevent the inadvertent lead contamination of samples, which has plagued many previous analyses of environmental and human lead levels. Advanced instrumentation is required to provide the sensitivity, accuracy, and precision that are needed to quantify the sublethal effects of lead concentrations at environmental levels of exposure. Fortunately, methodologies utilizing these advancements are now capable of addressing many of the important issues (e.g., lead biomolecular speciation, low exposure effects) in environmental and human lead toxicology.

Environmental Pollutants↗

PubMed1994

Characteristics of a white-footed mouse (Peromyscus leucopus) population inhabiting a polychlorinated biphenyls contaminated site.

Demographic characteristics of a white-footed mouse (Peromyscus leucopus) population inhabiting a woodland containing a low level of PCBs contamination were compared to an uncontaminated reference site. Although population density was higher on the PCBs-contaminated grid, the population exhibited greater temporal variability among years and had a higher number of transient animals. These population trends are consistent with those observed in structurally suboptimal habitats, indicating that the PCBs-contaminated grid is functioning as a suboptimal habitat. However, the data are not compelling enough to firmly conclude that the differences are due to contamination rather than to undetected environmental variation between sites. If demographic differences due to contamination are slight, they will be difficult to detect against a background of demographic variation resulting from subtle environmental differences. We conclude that animals at this site experienced a level of contamination that was below threshold for unequivocal detection of demographic effects.

Animals↗