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PubMed1990

Pregnancy outcomes in women potentially exposed to solvent-contaminated drinking water in San Jose, California.

During 1980-1981, solvents leaked from an underground storage tank of a semiconductor firm in southern Santa Clara County, California, contaminating local drinking water. The contaminated well was closed in December 1981. An epidemiologic study conducted in 1983 confirmed statistically significant excesses of adverse pregnancy outcomes in an exposed community compared with an unexposed community, but could not establish a causal connection between the leak and the adverse outcomes. This study expanded the first study; adverse pregnancy outcomes occurring in 1980-1985 were studied in two communities exposed to the contaminated drinking water and in two demographically comparable but unexposed communities. The period 1980-1981 was the time period in which the well was considered to have been contaminated and 1982-1985 was considered the postcontamination time period. Both exposed and unexposed communities were considered unexposed during the latter period (1982-1985). Out of 10,055 households surveyed, interviews were conducted with 1,105 women who reported one or more eligible pregnancies. Miscarriages and birth defects were validated by medical record review or physician reports. Although the authors again observed statistically significant excesses of spontaneous abortions and birth defects in the originally studied exposed area in 1980-1981, they observed deficits of these outcomes in the second exposed study area. Adjustment for potential confounders did not alter these findings. Analyses of pregnancy outcomes during 1981 in relation to exposure estimates based on hydrogeologic modeling of water and contaminant distribution within the exposed areas also indicated that the leak was not likely to have caused the observed excesses of adverse pregnancy outcomes in the originally studied area.

Abnormalities, Drug-Induced↗

PubMed2003

The effect of Pretoria Pasteurization on bacterial contamination of hand-expressed human breastmilk.

One of the challenges facing the development of programs to reduce mother to child transmission of HIV in developing countries remains the problem of infant feeding. One of the alternative feeding methods under investigation for infants of HIV-infected mothers is heat treatment of expressed breastmilk by Pretoria Pasteurization. The objective of this study was to determine the effect of Pretoria Pasteurization on commensal and pathogenic bacteria in hand-expressed human breastmilk, and to determine the duration of time for which milk can be kept safely without refrigeration after Pretoria Pasteurization. Samples of milk were hand expressed by lactating women in the postnatal ward. The samples were split into control and pasteurized specimens. The pasteurized specimens underwent Pretoria Pasteurization. All samples were stored at room temperature and were sampled for bacterial culture every 4 h, up to 12 h. Clinically significant levels of bacterial contamination occurred in 59 per cent of control and 7.8 per cent of pasteurized samples. Four pasteurized samples showed significant contamination. There is strong evidence that the contaminating organisms in these samples were introduced by handling after pasteurization. The 53 (91 per cent) pasteurized samples that had no contamination at 4 h remained sterile for the remainder of the standing period of 12 h. Forty-one per cent of control samples already had significant growth after standing at room temperature for 4 h. In conclusion, Pretoria Pasteurization kills pathogenic and commensal bacteria in hand-expressed breastmilk. Expressed breastmilk that has undergone Pretoria Pasteurization can be kept without refrigeration for up to 12 h with minimal probability of bacterial contamination provided that it is kept in the pasteurization container and is not handled.

Colony Count, Microbial↗

PubMed2005

Altered neonatal development and endocrine function in Alligator mississippiensis associated with a contaminated environment.

Reduced reproductive success, altered reproductive tract development, and differences in circulating hormones have been documented in American alligators (Alligator mississippiensis) from Lake Apopka, FL, compared to less contaminated sites, such as the Lake Woodruff National Wildlife Refuge, FL. Comparative studies among alligators of varying size and age suggest that in ovo contaminant-induced alterations of endocrine function are further modified during postembryonic development and/or through environmental exposure. In the present study, we examined developmental and endocrine-related indices in neonatal (age, <1 mo) alligators from Lake Apopka in comparison to those of a reference population (Lake Woodruff), thereby limiting contaminant exposure to that derived via maternal contribution. We compared several reproductive and developmental parameters, including hatching success, primary sex determination, and somatic indices. Furthermore, we examined circulating testosterone concentrations and aromatase activity in an effort to establish relative gonadal endocrine function shortly after hatching. Finally, we compared phallus size among males and oviduct epithelial cell height (ECH) among females (androgen- and estrogen-dependent tissues, respectively). Significant differences between populations were noted for body size and spleen somatic index. Neonatal alligators from Lake Apopka exhibited higher plasma testosterone, but no differences were detected in gonadal aromatase activity compared to Lake Woodruff. Phallus tip length and cuff diameter were smaller in males from Lake Apopka, whereas no differences were noted in oviduct ECH. Our data establish basic indices of development and endocrine function in neonatal alligators before environmental exposure to contaminants. These results should begin to help separate developmental abnormalities resulting from in ovo exposure, presumably of maternal origin, from physiological alterations induced through environmental exposure to contaminants.

Alligators and Crocodiles↗

PubMed1977

Contamination of medical gas and water pipelines in a new hospital building.

Medical gases and water were sampled and tested for purity prior to the opening of a 176-bed addition to a 450-bed general hospital. Contamination was found. In delivered oxygen, compressed air, and nitrous oxide, this consisted of a volatile hydrocarbon at an initial concentration of 10 parts per million and a dust of fine gray particulate matter. In water from new taps bacterial contamination with as many 400,000 organisms per 100 ml was present. All these contaminants were considered potential hazards to patient safety. Studies were done to help delineate the nature and origin of these contaminants. Each contaminant was eventually largely eliminated by purging the respective pipeline systems with continuous flows. Planners, builders, and responsible medical personnel must be aware of the potential for such hazards in a new hospital building.

Central Supply, Hospital↗

PubMed1994

Bacterial exposure required to induce rabbit calvarial bone graft infection by superficial contamination.

Little is known about the minimum bacterial dose required to induce infections by superficial contamination alone (i.e., not direct inoculation). This study quantified superficial rabbit calvarial bone graft contamination by exposing parietal bone grafts to Staphylococcus aureus. Two 5 x 5-mm full-thickness calvarial bone grafts were harvested from 40 rabbits and contaminated with different concentrations (range = 10(7)-10(11) colony-forming units [CFUs]/mL) of S. aureus by immersion. One graft from each rabbit was cultured immediately, and the other was inset into a calvarial donor site, fixed in place with wire, and observed for evidence of infection. At harvest (28 days postoperatively), a bacterial exposure of greater than 10(8) CFUs/mL of S. aureus was required to induce infections in the rabbit calvarial grafts (p < 0.001, Student's t-test), transmitting an infectious dose of approximately more than 10(4) CFUs per graft. These results validate the previously known dogma regarding the number of organisms needed to manifest infection [1,2] and highlight a multifold increment in bacterial count needed to transmit this infectious dose by superficial contamination alone. Such a model may be useful in investigating the efficacy of various treatment modalities of contaminated bone.

Air Microbiology↗

PubMed1990

A cohort study of 89 HIV-1-infected adult patients contaminated by blood products: Bordeaux 1981-1989. Groupe d'Epidémiologie Clinique du SIDA en Aquitaine (GECSA)

A hospital-based surveillance of HIV infection was implemented in the Bordeaux Regional University Hospital (France). This reporting system, initiated by the Groupe d'Epidemiologie Clinique du SIDA en Aquitaine, identified and followed-up 89 adult patients with transfusion-associated HIV-1 infection (7.2% of all reported cases). Contamination occurred between August 1981 and June 1985 and diagnosis was made between 1985 and 1989. By 30 June 1990, 43 patients (48.3%) had full-blown AIDS, and 28 of them had died. The mean follow-up period was 66 months (s.d. 16 months). The mean incubation period, i.e. The time interval between the contaminating transfusion and the development of full-blown AIDS, was 62 months [median 73 months; 95% confidence interval (CI) 66-82 months]. Five years after contamination, the cumulative probability of reaching the AIDS stage was 34.2% (95% CI 20.3-49.3%), and the probability of survival was 81.7% (95% CI 72.5-90.0%). From this surveillance system we estimate that in south-western France at the end of 1989 the cumulative incidence of transfusion-associated HIV-1 infection was at least 126 cases (45.6 per million inhabitants). Although we anticipate an increase in transfusion-associated AIDS cases over the next 5 years, there have been no reports of contamination after 1 August 1985, when systematic screening of HIV antibodies was implemented in French blood banks. This confirms the efficacy of screening in countries like France where the risk of contamination through blood products is now minimal.

Acquired Immunodeficiency Syndrome↗

PubMed1990

Ground distribution patterns of selected radioactive, chemical, and physical contaminants from dispersion of U mill tailings.

Ground concentrations of 226Ra and total alpha activity as a function of soil depth and distance from an acidic U mill tailings pile were measured, as well as soil pH, sulfate, chloride, and conductivity. Contamination decreased with increasing soil depth and distance from the source. Most of the measured parameters were indistinguishable from background after a distance of 3.3 km from the tailings impoundment. The highest concentrations of all contaminants were contained in the particles less than 0.045 mm in diameter at the soil surface (0-0.6 cm). This fraction represents only 4% to 10% of the total soil mass. Surface soil particles greater than 2.0 mm contained higher concentrations of all contaminants than the intermediate-size (0.045-2.0 mm) fraction. Aggregate formation of the greater than 2.0-mm fraction from small particles or preferential erosion and transport of the tailings sand fractions were proposed as possible explanations. The significant correlations between various measurements were soil 226Ra vs. total alpha activity, sulfate concentration, and conductivity. The latter two parameters are indicative of sulfuric acid leached tailings. The sulfate concentration appeared to be a sensitive and easily measured indicator of tailings contamination and migration into the soil profile. Furthermore, sulfate may be used to delineate acidic U tailings from other sources of contamination (U ore dust, yellowcake, naturally elevated U and Ra) in the environment. Actual site measurements for surface 226Ra concentration were approximately twice the MILDOS computer code prediction.

Chlorides↗

PubMed1997

Characterization and solubility measurements of uranium-contaminated soils to support risk assessment.

Remediation of uranium-contaminated soils is considered a high priority by the U.S. Department of Energy because these soils, if left untreated, represent a hazard to the environment and human health. Because the risk to human health is a function of the solubility of uranium in the soils, the objectives of this work are to measure the uranium solubility of two contaminated soils, before and after remedial treatment, and determine the health risk associated with these soils. Two carbonate-rich, uranium-contaminated soils from the U.S. Department of Energy Fernald Environmental Management Project facility near Cincinnati, Ohio, as well as two nearby background soils were characterized and their uranium solubility measured in a 75-d solubility experiment using acid rain, groundwater, lung serum, and stomach acid simulants. Results show that the soluble uranium levels of each soil by each simulant are greatly influenced by their contamination source term. Risk calculations and biokinetic modeling based on the solubility data show that the risks from the soil ingestion and groundwater ingestion pathways are the predominant contributors to the total carcinogenic risk, whereas the risk from the soil inhalation pathway is the smallest contributor to this risk. However, kidney toxicity was the greater health concern of the Fernald Environmental Management Project soils, primarily from undiluted ingestion of the groundwater solution following contact with the contaminated soils. Sensitivity analyses indicate that uranium solubility is a key parameter in defining kidney toxicity; therefore, without proper consideration of the solubility of radionuclides/metals in untreated and treated soils, important factors may be overlooked which may result in soil cleanup goals or limits which are not protective of human health and the environment. We recommend that characterization and measurement of target radionuclides/metals solubilities should also be required by the regulatory community to support the establishment of scientifically-sound, site-specific, soil cleanup goals or limits.

Acid Rain↗

PubMed1997

60Co contamination in recycled steel resulting in elevated civilian radiation doses: causes and challenges.

Since late 1992, more than 100 building complexes containing public and private schools and nearly 1,000 apartments have been identified in Taiwan with elevated levels of gamma-radiation from construction steel contaminated with 60Co. Due to improper handling of 60Co contaminated scrap steel in late 1982 and 1983, contaminated construction materials have been widely distributed throughout the country. These contaminated construction materials have generated elevated radiation exposures to members of the public in Taiwan. As of early 1996, more than 4,000 people, including young students, have been identified as receiving more than 1 mSv y(-1) above the local background for up to 12 y. This report provides a detailed discussion of the sources of the 60Co contamination in construction steel, its discovery in the building complexes, and preliminary evaluation and remediation activities.

California↗

PubMed1998

An improved mouth-piece to prevent environmental contamination during radioaerosol inhalation procedures.

The literature suggests that environmental contamination is common during labeled aerosol inhalation procedures in nuclear medicine. We have tested an adherent mask to prevent environmental contamination in 70 procedures. Two groups of patients were evaluated. Group 1 (60 inhalation cases in which the mask was used) presented no environmental contamination in 95% of the procedures (means of 553 dpm and 596 dpm before and after inhalation, p > 0.05, mean of the differences before/after inhalation 6.95, SD = 21.2 dpm) and the only 3 cases in which contamination did occur concerned bearded men; Group 2 (10 inhalation cases in which the mask was not used) showed large increases of environmental radioactive levels in 70% of the procedures (means of 601 dpm and 2,756 dpm before and after inhalation, p < 0.05, mean of the differences 3,066, SD = 2,98 dpm). We conclude that such a mask is very helpful in avoiding environmental contamination during radioaerosol inhalation procedures.

Administration, Inhalation↗

PubMed2001

A dose reconstruction of 60Co-contaminated window frames in a Taiwanese school.

Since 1992, hundreds of buildings in Taiwan were discovered to have 60Co contamination in the structural rebar. The contamination resulted from improper handling of 60Co-contaminated scrap metal in 1982 and 1983, which subsequently was recycled and used throughout Taiwan. Hsin-hsin Kindergarten school enrolled about 600 students over the 10-y period before the contamination was discovered. Hsin-hsin Kindergarten had three 60Co-contaminated steel window frames with measured dose rates on contact up to 150 microSv h(-1). In this study, a range of potential doses received by the Hsin-hsin Kindergarten students were estimated using ISOSHLD dose modeling software. ISOSHLD is a rapid, inexpensive screening tool to reconstruct dose ranges. To assess the potential risks to habitants of the school for the first year after construction, calculated dose rate ranges of 0.08 microSv h(-1) to 75.38 microSv h(-1) were then applied to the International Commission [corrected] on Radiation Protection 60 nominal detriment coefficients for stochastic effects. Risk estimates ranged from 1.46 x 10(-4) to 7.42 x 10(-4) excess fatal cancers per lifetime.

Adolescent↗

PubMed2002

The probability of finding a localized area with elevated contamination by using a mobile detector.

This paper examines the probability that a localized area with elevated contamination can be found by using a mobile detector. In the case studied, the area of elevated contamination has an elliptical shape and the detector has a circular field of view. The probability of finding the contaminated area is a function of factors related to both the contaminated area and the detector. The paper examines the dependence of the probability on a number of these factors. The results presented are applicable to any characteristic that can be detected with a scanning system that provides complete coverage of an area. They can be used as the basis for designs or evaluations that involve determining whether localized areas of contamination are present in an area of interest.

Environmental Monitoring↗

PubMedDate not supplied

Realignment of emission contaminated attenuation maps with uncontaminated attenuation maps for attenuation correction in PET.

PURPOSE: We investigated aligning a transmission (T) scan with a subsequent emission contaminated transmission (T+E) scan. This would permit correction for patient motion and thereby use of a single T scan to correct E scans taken hours or days apart. METHOD: Scans from 15 patients were used to produce 200 T scans contaminated with two levels of either [18F]fluorodeoxyglucose or [13N]ammonia E data. Known misalignments were introduced between each T+E scan and the corresponding T scan, and each pair was subsequently realigned. Realignment errors were compared with those obtained for uncontaminated T scans. RESULTS: The realignment errors increase with the contamination level and depend slightly on the contaminant. However, even at the highest level of contamination studied, the mean absolute translation errors remained less than the voxel size and the mean absolute rotation errors were < 2.5 degrees. CONCLUSION: AT+E scan can be accurately realigned with a T scan. This suggests that attenuation correction could be performed by using a high quality T scan taken days or hours earlier and aligning this T scan with a short T scan taken immediately after E imaging.

Heart↗

PubMed1996

Contamination risks from a high-speed bone burr.

STUDY DESIGN: The authors recorded the contamination rate at a mock surgical site below a high-speed burr creating debris from a fresh-frozen allograft specimen. OBJECTIVES: To document possible contamination rates associated with high-speed burr use. SUMMARY OF BACKGROUND DATA: The literature contained no studies addressing a known rate of contamination from high-speed burr use. METHODS: Samples of debris were collected in a mock-up of an operation involving bone burring. Set distances were maintained between objects within the field. High-speed bone burring was performed on fresh-frozen allograft bone specimens, and falling debris was collected on sterile culture plates. Control specimens were obtained randomly. Two hundred test and 20 control samples were collected by means of standard sterile techniques. RESULTS: Thirty-five percent of the cultured specimens from the test group grew skin flora, compared with 10% from the control group (P = 0.02). CONCLUSIONS: The authors propose that the higher contamination rate in the experimental samples resulted from airborne bone chips striking nonsterile surfaces before landing on the culture plates. Such contamination may increase the risk of wound infection.

Bacteria↗

PubMed1997

Influence of acinar tissue contamination on encapsulated pancreatic islets: morphological and functional studies.

BACKGROUND: The present study concerns the influence of acinar contamination on pancreatic islets encapsulated in an artificial membrane (AN 69). METHODS: Pure, handpicked pancreatic islets were contaminated by the addition of acinar tissue (ratio, 1:1). The morphological aspect and insulin release of both pure (n=12) and contaminated (n=12) encapsulated islets were assessed after 10 days of culture or implantation in the peritoneal cavity of rats. RESULTS: After implantation, the encapsulated islets, irrespective of their purity, were totally altered, whereas the morphological aspect of the cultivated islets remained intact only in the absence of acinar tissue contamination. This contamination induced a significant decrease in the stimulation index of insulin release. The stimulation index decreased by 42% for fresh islets and by 52% and 34% for cultivated and implanted islets, respectively, without modification in their basal release of insulin. CONCLUSIONS: The acinar tissue proved detrimental to the encapsulated implanted and cultivated islets.

Animals↗

PubMed2000

Ammonium perchlorate contamination of Colorado River drinking water is associated with abnormal thyroid function in newborns in Arizona.

The Colorado River below Lake Mead, which supplies drinking water for approximately 20,000,000 people, is contaminated by ammonium perchlorate. We identified populations who were exposed and unexposed to perchlorate-contaminated drinking water and compared median newborn thyroid-stimulating hormone (TSH) levels after adjusting for age in days at measurement and for race/ethnicity. Median newborn TSH levels in a city whose drinking water supply was 100% perchlorate-contaminated water from the Colorado River below Lake Mead were significantly higher than those in a city totally supplied with non-perchlorate-contaminated drinking water, even after adjusting for factors known or suspected to elevate newborn TSH levels. This ecological study demonstrates a statistically significant association between perchlorate exposure and newborn TSH levels. It suggests that even low-level perchlorate contamination of drinking water may be associated with adverse health effects in neonates and highlights the need for both further study and control of human low-level perchlorate exposure.

Analysis of Variance↗

PubMed2005

Contaminant seeding in bone by different irrigation methods: an experimental study.

OBJECTIVE: This study was designed to investigate the effectiveness of using various devices and manual procedures for cleansing bacterially contaminated bone tissue and to assess the risk of iatrogenic bacterial seeding in deep bone layers. METHODS: In an in vitro model, human femoral heads were contaminated with Escherichia coli and then cleansed with pulsatile high-pressure lavage, pulsatile low-pressure lavage, manual rinsing with bulb syringe lavage, or manual rinsing with combined brush cleaning. The numbers of bacteria that remained or those that were introduced by the rinsing procedures were quantitatively determined at depths of 0 to 1 cm, 1 to 2 cm, and 2 to 3 cm. RESULTS: Both pulsatile high-pressure lavage and brush cleaning were more effective than pulsatile low-pressure lavage and bulb syringe lavage for the purpose of surface cleansing. The differences were highly significant (P < 0.001). There was no significant difference in the decontaminating effect between pulsatile high-pressure lavage and brush cleaning (P = 0.24). The bacterial contamination attributable to the cleansing procedure, as measured at tissue depths of 1 to 2 cm and 2 to 3 cm, was significantly higher after pulsatile high-pressure lavage and after pulsatile low-pressure lavage than it was after bulb syringe lavage or brush cleaning (P < 0.001). CONCLUSION: In this in vitro investigation of cancellous bone, the brush cleansing was just as effective for getting rid of bacterial contamination as pulsatile high-pressure lavage, and carries a significantly lesser risk of iatrogenic bacterial seeding into deeper tissue layers. In the light of these promising results obtained by the cleansing of cancellous bone contaminated with bacteria, it would be desirable to perform supplementary in vitro and in vivo investigations into brush cleansing.

Aged↗

PubMed2002

The development of a sub-surface monitoring system for organic contamination in soils and groundwater.

A major problem when dealing with environmental contamination is the early detection and subsequent surveillance of the contamination. This paper describes the potential of sub-surface sensor technology for the early detection of organic contaminants in contaminated soils, sediments, and landfill sites. Rugged, low-power hydrocarbon sensors have been developed, along with a data-logging system, for the early detection of phase hydrocarbons in soil. Through laboratory-based evaluation, the ability of this system to monitor organic contamination in water-based systems is being evaluated. When used in conjunction with specific immunoassays, this can provide a sensitive and low-cost solution for long-term monitoring and analysis, applicable to a wide range of field applications.

Environmental Monitoring↗