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PubMed2001

The accumulation and effects of environmental contaminants on snakes: a review.

In any ecological risk assessment, a full complement of the relevant members of the ecosystems being studied should be considered. Reptiles in general, and snakes in particular, are important although often neglected components of terrestrial and aquatic ecosystems and should be included in any study on environmental contamination. By neglecting reptiles, the risks posed by a particular contaminant cannot be fully assessed. Since all snakes are secondary, tertiary, and top predators, they are susceptible to the bioaccumulation of environmental contaminants. Their unique life histories make their roles in food webs diverse and important, and they are crucial to the proper functioning of many ecological processes. We review and summarize organic and inorganic contaminant and radionuclide/radiation residue and lethal and sublethal effects data for snakes to stress the importance of snakes and encourage their inclusion in ecological risk assessments, to demonstrate the paucity of available contaminant data on snakes and reveal the main information gaps, to encourage further ecotoxicological studies on snakes, and to facilitate the use of existing snake contaminant data in ecological risk assessments. This review is the most comprehensive review currently available on the effects on and accumulation of environmental contaminants in snakes.

Animals↗

PubMedDate not supplied

Gonadal feminization and halogenated environmental contaminants in common terns (Sterna hirundo): evidence that ovotestes in male embryos do not persist to the prefledgling stage.

Common terns (Sterna hirundo) and roseate terns (Sterna dougallii) breed on Bird Island, Massachusetts, USA, near a Superfund site highly contaminated with polychlorinated biphenyls (PCBs). Observations of skewed sex ratios and female-female pairings among endangered roseate terns (Nisbet and Hatch (1999) Ibis 141, 307) suggested the possibility of contaminant-related endocrine disruption in these birds and prompted investigation of common terns as a surrogate species. In 1993 and 1994, 60-90% of pipping male common tern embryos sampled exhibited ovarian cortical tissue in their testes (ovotestes) (Nisbet et al. (1996) Bull. Environ. Contam. Toxicol. 57, 895; Hart et al. (1998) Mar. Environ. Res. 46, 174). To examine the possible impact of ovotestes on the reproductive capabilities of common terns, we examined gonadal histology in common tern prefledglings (approximately 21 days old) collected from Bird Island in 1995. As a measure of embryonic contaminant exposure, contaminants were measured in a subset of eggs collected from the same nests as the prefledglings. Concentrations of total PCBs in these eggs ranged from 14.4 to 546 microg/g lipid. No evidence of ovotesticular development was observed in any of the 19 male prefledglings examined. Some gonadal irregularities were observed, including small nodules of testicular tissue within the epithelial capsule of the testes, but these were judged not likely to affect testicular function. There was no relationship between any observed irregularities and levels of contaminants present in the matched eggs. The results suggest that the ovotestes that occur in 60-90% of pipping common tern embryos from this site become fully regressed by approximately 21 days posthatch. Our data from this and previous studies are consistent with the idea that ovotestes occur naturally in some individual common terns at hatching, although the frequency of occurrence may be enhanced by exposure to chlorinated organic contaminants such as PCBs. In either case, we suggest that the presence of ovotestes in common tern embryos from PCB-contaminated sites such as Bird Island does not lead to permanent alterations in gonadal histology that would be expected to impair reproductive function.

Animals↗

PubMed2001

Ambient air quality monitoring network design for assessing human health impacts from exposures to airborne contaminants.

Existing methods of establishing ambient air quality monitoring networks typically evaluate only parameters related to ambient concentrations of the contaminant(s) of interest such as emission source characteristics, atmospheric transport and dispersion, secondary reactions, deposition characteristics, and local topography. However, adverse health risks from exposures to airborne contaminants are a function of the contaminant and the anatomic and physiologic characteristics of the exposed population. Thus, ambient air quality monitoring networks designed for the protection of public health or for epidemiological studies evaluating adverse health impacts from exposures to ambient air contaminants should account for both contaminant characteristics and human health parameters. A methodology has been established which optimizes ambient air quality monitoring networks for assessments of adverse human health impacts from exposures to airborne contaminants by incorporating human health risk assessment techniques. The use of risk assessment techniques as the basis for designing ambient air quality monitoring networks will help to target limited financial and human resources to evaluate human health risks from exposures to airborne contaminants.

Air Pollutants↗

PubMed2006

What is the clinical significance of infusing hematopoietic cell grafts contaminated with bacteria?

Although hematopoietic stem cell (HSC) products are routinely cultured for sterility, bacterial contamination of these products is rarely observed and little is known about the clinical consequences of infusing contaminated grafts. We retrieved the sterility cultures of bone marrow and peripheral HSC grafts from 938 patients transplanted at our center from January 1990 to July 2005. Fever, septicemia and other adverse events were assessed for up to 14 days following infusion of the graft. Out of the 1502 grafts collected during this 15-year period, 15 (1.0%) had a positive sterility culture (11 Gram-positive cocci, 2 Gram-positive bacilli and 2 Gram-negative bacilli). No correlation was observed between the graft contamination rate and the extent of graft manipulation or the patient's underlying condition. Thirteen recipients were transplanted with contaminated grafts. Five patients were treated with specific pre-emptive antibiotics. Only one episode of Staphylococcus epidermidis bacteremia possibly related to a contaminated graft was observed on day +5. As the infusion of contaminated grafts with Gram-positive skin contaminants rarely results in unfavorable clinical outcomes, close patient monitoring without the use of specific pre-emptive antibiotics could be appropriate and could avoid antibiotic-associated adverse events.

Adult↗

PubMed1999

False human hematopoietic cell lines: cross-contaminations and misinterpretations.

The risk of adventitious contamination and subsequent overgrowth of cell lines by unrelated cells is a potential and often recurring problem where cells are grown and studied. This problem of intraspecies and interspecies cross-contamination among human cell lines has been recognized for over 25 years; incidences of cell cross-contamination between 17 and 35% have been reported. The most useful methods to detect human cell cross-contamination are DNA fingerprinting and cytogenetic analysis, each complementing the other. Using this combination, we found that in total 14.8% of the human hematopoietic cell lines received either from the original investigator (n = 117 cell lines) or from secondary sources (n = 72 cell lines) were cross-contaminated with another hematopoietic cell line and were thus false cell cultures. Another problem relates to the fact that not every cell line established from a patient with a hematopoietic malignancy is a malignant cell line; unintended immortalization of non-malignant B cells by 'passenger' Epstein-Barr virus (EBV) leads to the establishment of B-lymphoblastoid cell lines (termed EBV+ B-LCLs), an event which is much more frequent than the establishment of a 'true' leukemia-lymphoma-myeloma cell line. These EBV+B-LCLs are most often (albeit not always) unrelated to the malignant clone. The misinterpretation of such EBV+ B-LCLs as true malignant hematopoietic cell lines (particularly in research areas investigating B cell-derived neoplasms such as myeloma) and the indiscriminate use of these cell lines may render some of the results of such studies irrelevant to the pathobiology of the disease concerned. However, a combination of markers commonly allows for an accurate determination of the nature of EBV+ B-LCLs: immunoprofile, cellular morphology, EBV status, and karyotype. In summary, the continuous need for vigilant quality and identity control procedures is emphasized by the high incidences of cross-contaminated cell lines. Most laboratories using cells cultured in vitro maintain multiple cell lines. Such cell lines should be monitored regularly for their identity and specific characteristics in order to prevent invalidation of research work due to incidents of cell line cross-contamination or misinterpretation.

Cell Culture Techniques↗

PubMed2005

Fractionation and elemental association of Zn, Cd and Pb in soils contaminated by Zn minings using a continuous-flow sequential extraction.

Fractionation and elemental association of Zn, Cd, and Pb in soils near Zn mining areas were studied using a continuous-flow sequential extraction approach. The recently developed sequential extraction procedure not only gave fractional distribution data for evaluation of the mobility or potential environmental impact of the metals, but also the extraction profiles (extractograms) which were used for study of elemental association. In addition, the elemental atomic ratio plot extractogram can be used to demonstrate the degree of anthropogenic contamination. Seventy-nine soil samples were collected in the vicinity of a Zn mine and were fractionated into 4 phases i.e. exchangeable (F1), acid soluble (F2), reducible (F3) and oxidizable (F4) phases. Most samples were contaminated with Zn, Cd and Pb. The reducible phase is the most abundant fraction for Zn and Pb (>50%) while Cd is concentrated in the first 3 extraction steps. The distribution patterns of Cd were obviously affected by soil pH. 55% of Cd appears predominantly in the F1 fraction for acidic soils while in neutral and alkaline soils, it was mostly (70%) found in the F2 + F3 fractions. The extractograms obtained from the continuous-flow extraction system revealed close association between Zn, Cd, Pb and Fe in the acid soluble phase, Cd-Pb and Zn-Fe in the reducible phase for contaminated soils. A correlation study of the 3 metals using a correlation coefficient was also performed to compare the results with the elemental association revealed by the extractograms. Atomic ratio plot extractograms of Zn/Fe, Cd/Fe and Pb/Fe in the reducible phase, where contaminated metals are predominant, can be used to evaluate the degree of anthropogenic contamination. From the elemental atomic ratio plot, it is obvious that the contaminants Cd and Pb are mostly adsorbed on the surface of Fe oxides. Zn, which is present in an approximately 1 ratio 1 ratio with Fe in contaminated soils, does not show a similar trend to that found for Cd and Pb.

Chemical Fractionation↗

PubMed2003

Investigation of Salmonella contamination and disinfection in farm egg-packing plants.

AIMS: As part of a field-based study of the distribution and persistence of Salmonella infection on commercial egg-laying farms, sampling was carried out on one or more occasions in egg-packing areas of 12 farms infected with Salm. Enteritidis. METHODS AND RESULTS: Salmonellas were isolated by cultural methods. Contamination was common, with Salmonella being found in 23.1% of floor swab samples, 30.8% of grading tables, 23.1% of conveyor belts or rollers and 23.8% of candlers. Four farms were sampled after cleaning and disinfection of packing plants had been carried out on the previous day, and residual contamination was found on 6.9% of samples from grading tables, 16.0% holding/sorting tables, 12.6% of conveyors or rollers, 16.7% of vacuum egg lifters, 21.4% of floor surfaces and 5.0% of egg store floor surfaces. Sterilized eggs passed through five farm packing plants showed a contamination rate of at least 16/5,948 (0.3%) egg passages. CONCLUSIONS: It is apparent that contamination in egg-packing plants may be a significant contributory factor to external contamination of shell eggs, and improved methods of cleaning and disinfecting egg-handling equipment are required. SIGNIFICANCE AND IMPACT OF THE STUDY: The presence of Salmonella contamination in egg-packing plants presents a contamination hazard for eggs from Salmonella-free flocks. Samples from equipment in the packing plant could also be used for screening for detection of Salmonella in the throughout of the plant.

Agriculture↗

PubMed2003

Salmonella on pig carcasses: positive pigs and cross contamination in the slaughterhouse.

AIMS: The purpose of this study was to investigate the prevalence of Salmonella in pigs at the moment of slaughter and in the slaughterhouse environment. METHODS AND RESULTS: In total, five different commercial slaughterhouses were sampled during eight slaughterhouse visits. Carcass swabs, colon content and mesenteric lymph nodes were taken to reflect the animal status and from the slaughterhouse environmental samples were taken. Salmonella was isolated from 37% of the carcass samples as a mean value. High variations were noticed between different slaughterhouses (between 0 and 70%) and sampling days in the same abattoir (between 3 and 52%). A correlation was found between the carcass contamination and the status of the delivered animals (P=0.01675). Cross contamination was estimated to account for 29% of the positive carcasses. The slaughterhouse environment was highly contaminated; before starting the slaughtering activities 25% of the samples were positive on average. The most prevalent serotypes isolated at the slaughterhouse environment and from the colon content were S. Typhimurium, S. Livingstone and S. Derby. On carcasses S. Typhimurium was predominately isolated (71%). The biggest variability of serotypes was found in the mesenteric lymph nodes. Serologically 56.3% of the pigs were found positive for Salmonella using a cut-off level of the optical density percentage higher than 10 (O.D.% > or = 10). While on individual pig level the correlation between the bacteriological and serological data was poor, because of recent Salmonella infections, a better correlation was found at the herd level on the moment of slaughtering. CONCLUSION: A high degree of carcass contamination is noticed after slaughtering. This contamination resulted from the delivery of Salmonella-positive pigs and cross-contamination from the slaughterhouse environment. SIGNIFICANCE AND IMPACT OF THE STUDY: In pigs, Salmonella carriage is high, but it is obvious that slaughterhouse hygiene is a determinative factor for managing carcass contamination.

Abattoirs↗

PubMed2003

Genetic variation among interconnected populations of Catostomus occidentalis: implications for distinguishing impacts of contaminants from biogeographical structuring.

Exposure to contaminants can affect survivorship, recruitment, reproductive success, mutation rates and migration, and may play a significant role in the partitioning of genetic variation among exposed and nonexposed populations. However, the application of molecular population genetic data to evaluate such influences has been uncommon and often flawed. We tested whether patterns of genetic variation among native fish populations (Sacramento sucker, Catostomus occidentalis) in the Central Valley of California were consistent with long-term pesticide exposure history, or primarily with expectations based on biogeography. Field sampling was designed to rigorously test for both geographical and contamination influences. Fine-scale structure of these interconnected populations was detected with both amplified fragment length polymorphisms (AFLP) and microsatellite markers, and patterns of variation elucidated by the two marker systems were highly concordant. Analyses indicated that biogeographical hypotheses described the data set better than hypotheses relating to common historical pesticide exposure. Downstream populations had higher genetic diversity than upstream populations, regardless of exposure history, and genetic distances showed that populations from the same river system tended to cluster together. Relatedness among populations reflected primarily directions of gene flow, rather than convergence among contaminant-exposed populations. Watershed geography accounted for significant partitioning of genetic variation among populations, whereas contaminant exposure history did not. Genetic patterns indicating contaminant-induced selection, increased mutation rates or recent bottlenecks were weak or absent. We stress the importance of testing contaminant-induced genetic change hypotheses within a biogeographical context. Strategic application of molecular markers for analysis of fine-scale structure, and for evaluating contaminant impacts on gene pools, is discussed.

Analysis of Variance↗

PubMed1996

Bacterial contamination of peripheral blood progenitor cells for transplantation.

Peripheral blood progenitor cells (PBPC) were obtained from 128 apheresis harvests on 64 patients and were tested in duplicate for microbiological contamination (1) after collection and (2) after thawing, following processing and cryopreservation. In this study we have attempted to improve the monitoring of contamination in peripheral blood progenitor cell collections by identifying exogenous contamination that probably originated from the testing laboratory and is therefore not clinically significant. We found no contamination in 82% of harvests, 1.6% of harvests to be significantly contaminated and organisms were isolated from 16.4% that were assessed as clinically nonsignificant. Our experience indicates that the choice of microbiological methods will influence the results and their clinical relevance. No samples were positive by direct culture. We recommend that sampling should be performed at more than one stage during the procedure and that initially only the post-thaw samples be analysed. Testing should be performed by enrichment culture in duplicate only and if positive to aid interpretation the post-collection sample should then be cultured. No patient given nonsignificantly contaminated graft without antibiotic cover suffered infection from the identified organism. The incidence of significant contamination was low and we recommend that in these cases PBPC grafts can be infused safely provided prophylactic antibiotic cover is given.

Bacteriological Techniques↗

PubMed1996

Bacterial contamination rates following processing of bone marrow and peripheral blood progenitor cell preparations.

BACKGROUND: The performance of cultures to assess possible bacterial contamination of bone marrow and peripheral blood progenitor cell preparations is required by the standards of the American Association of Blood Banks. STUDY DESIGN AND METHODS: Consecutive (n = 893) bone marrow and peripheral blood progenitor cell preparations were cultured for assessment of possible contamination by microorganisms. RESULTS: Consecutive bone marrow and peripheral blood progenitor cell preparations (n = 893) were cultured; the overall positive rate detected was 2.5 percent (22/893). The isolates predominantly were skin contaminants (gram-positive cocci) and so-called water-borne organisms (gram-negative rods). The 6.0-percent rate of positivity in 317 bone marrow preparations was higher than the 0.5-percent rate in 576 peripheral blood progenitor cell preparations (p < 10(-6)). Culture-positive preparations were transfused to 16 patients at this institution; however, none of these transfusions led to documented sepsis with the contaminating organism. CONCLUSION: The culture method described here complies with the standards of the American Association of Blood Banks. Contamination can be detected in both bone marrow and peripheral blood progenitor cell preparations. When contaminated preparations are transfused, there are few complications that can be attributed to the contamination.

Blood↗

PubMedDate not supplied

Contamination of pigs by nose-to-nose contact or airborne transmission of Salmonella Typhimurium.

The aim of this study is to assess the risk of contamination by Salmonella Typhimurium of pigs by nose-to-nose contact or the airborne route. Thirty twelve-week-old SPF pigs were divided into 4 groups housed in 4 different rooms: the first room contained Salmonella-free control pigs (n = 4), the second room had 10(3) CFU S. Typhimurium inoculated pigs (n = 5) and non-inoculated "contact" pigs (n = 4), the third room had pigs (n = 8) receiving potentially contaminated air from the following room through a hole (4 pigs housed in the pen situated near the hole and 4 pigs in the pen at the opposite side of the room), and the fourth room had pigs (n = 5) inoculated with 10(6) CFU Salmonella Typhimurium and also non inoculated "contact" pigs (n = 4). The "contact" and the inoculated pigs were housed in adjacent pens allowing nose-to-nose contact. The 5 pigs orally inoculated with 10(6) CFU S. Typhimurium were bacteriologically and serologically positive 1 week later and their environment was contaminated as early as 1 day pi. The faecal samples of 4 nose-to-nose contact pigs were bacteriologically positive and one of them was seropositive 5 weeks pi before the pigs were commingled. The 8 pigs housed in the third room received S. Typhimurium by an active airflow coming from the contaminated room (1000 m3/hour). Their faecal samples remained negative until 8 weeks pi but the environmental swabs taken in the room close to the airinlet were contaminated 2 days pi and positive swabs were found elsewhere in the room 5 weeks pi. Two seropositive pigs were encountered 8 weeks pi in the pen situated near the hole. Only one among the 5 pigs inoculated with 10(3) CFU had bacteriologically positive faeces 1-week pi and the 4 pigs kept in nose-to-nose contact with them remained negative. A dose of 10(3) CFU was too small to induce persistent excretion and to stimulate a humoral immune response. However, the dose of 10(6) CFU induced contamination of nose-to-nose contact pigs and contamination of the environment by airflow.

Air Microbiology↗

PubMed2000

The index of microbial air contamination.

The standard index of microbial air contamination (IMA) for the measurement of microbial air contamination in environments at risk is described. The method quantifies the microbial flow directly related to the contamination of surfaces coming from microbes that reach critical points by falling on to them. The index of microbial air contamination is based on the count of the microbial fallout on to Petri dishes left open to the air according to the 1/1/1 scheme (for 1h, 1m from the floor, at least 1m away from walls or any obstacle). Classes of contamination and maximum acceptable levels have been established. The index of microbial air contamination has been tested in many different places: in hospitals, in food industries, in art galleries, aboard the MIR space station and also in the open air. It has proved to be a reliable and useful tool for monitoring the microbial surface contamination settling from the air in any environment.

Air Microbiology↗

PubMed2001

The grazing response of cattle to pasture contaminated with rabbit faeces and the implications for the transmission of paratuberculosis.

Transmission of Mycobacterium avium subspecies paratuberculosis, the organism responsible for paratuberculosis (or Johne's disease) in ruminants, occurs through the faecal-oral route. As M. a. paratuberculosis has been isolated from rabbit faeces, cattle grazing rabbit faecal contaminated pasture may thus be at risk.A herd of 57 beef cattle was monitored on a farm in Perthshire, throughout the 1999 'grazing year', to investigate whether the cattle avoided rabbit faecal contaminated pasture and thus the potential for disease transmission. Grazing was measured every two days over eight rotations by sward heights on 40 marked treatment plots (0.5 m x 0.5 m) to which 0, 10, 50 and 250 rabbit faecal pellets were added. Cattle were also monitored by an active transponder system which enabled individual animals contacting two plots per field rotation (one control and one contaminated) to be recorded. During the monitored grazing year, grazing pressure was low with a net mean sward offtake of 18% of sward height per rotation. There were no significant differences between rabbit faecal treatments (0, 10, 50 and 250 pellets) with respect to the height or proportion of sward removed, or between the numbers of contacts made by cattle on contaminated and uncontaminated plots. Over 90% of all the cattle contacted contaminated plots, indicating that the potential for disease transmission was widespread among the herd. To our knowledge, this is the first reported instance of a lack of avoidance by grazing cattle towards swards contaminated with faeces, and implies that the potential for transmission of paratuberculosis from rabbit contaminated pasture is high.

Animal Husbandry↗

PubMedDate not supplied

[Risk assessment of soil contamination in a residential area: the importance and role of human biological monitoring--a case report].

BACKGROUND AND PURPOSE: High levels of arsenic, cadmium, mercury and polychlorinated dibenzodioxins and dibenzofuranes (PCDD/PCDF) were detected in the soil of a residential area located at the river Elbe near Hamburg (Germany). Soil contamination resulted from sediments from the Hamburg harbour and from the Elbe that were deposited in this area up to the late 1950ies. The objective of this study was to evaluate whether the soil contamination in this area is associated with increased levels of arsenic, heavy metals and PCCD/PCDF in the blood and urine of selected residents living on highly contaminated grounds. RESULTS: The blood levels of lead and PCDD/PCDF and the urine levels of arsenic, cadmium and mercury that were measured in 29 residents living on highly contaminated grounds were not elevated in relation to a control group. All individual values were in the range of the background exposure levels of the general population. There were no signs of an increased additional exposure related to soil contamination. CONCLUSIONS: Based on the results of this study it was agreed to refrain from an expensive redevelopment of this area. As a preventive measure some recommendations were given to the residents to minimize possible exposure to soil contaminants. Human biological monitoring studies should be an essential part of exposure and risk assessment of soil contaminations in residential areas in future studies and as a basis for adequate risk management.

Arsenic↗

PubMed1999

Contaminant bioavailability in soils, sediments, and aquatic environments.

The aqueous concentrations of heavy metals in soils, sediments, and aquatic environments frequently are controlled by the dissolution and precipitation of discrete mineral phases. Contaminant uptake by organisms as well as contaminant transport in natural systems typically occurs through the solution phase. Thus, the thermodynamic solubility of contaminant-containing minerals in these environments can directly influence the chemical reactivity, transport, and ecotoxicity of their constituent ions. In many cases, Pb-contaminated soils and sediments contain the minerals anglesite (PbSO4), cerussite (PbCO3), and various lead oxides (e.g., litharge, PbO) as well as Pb2+ adsorbed to Fe and Mn (hydr)oxides. Whereas adsorbed Pb can be comparatively inert, the lead oxides, sulfates, and carbonates are all highly soluble in acidic to circumneutral environments, and soil Pb in these forms can pose a significant environmental risk. In contrast, the lead phosphates [e.g., pyromorphite, Pb5(PO4)3Cl] are much less soluble and geochemically stable over a wide pH range. Application of soluble or solid-phase phosphates (i.e., apatites) to contaminated soils and sediments induces the dissolution of the "native" Pb minerals, the desorption of Pb adsorbed by hydrous metal oxides, and the subsequent formation of pyromorphites in situ. This process results in decreases in the chemical lability and bioavailability of the Pb without its removal from the contaminated media. This and analogous approaches may be useful strategies for remediating contaminated soils and sediments.

Journal Article↗

PubMed2004

Evidence for increased internal exposure to lower chlorinated polychlorinated biphenyls (PCB) in pupils attending a contaminated school.

External and internal exposure to six WHO-indicator congeners of polychlorinated biphenyls (PCB 28, 52, 101, 138, 153, 180) as well as subjective health complaints of a group of 377 pupils attending a PCB-contaminated school were compared with a control group of 218 pupils attending a non-contaminated school. Indoor air of the contaminated school revealed total PCB concentrations (sum of six indicator congeners times 5) ranging between 690 and 20,800 ng/m3 (median 2044 ng/m3). The lower chlorinated congeners PCB 28, 52, 101 were the prevailing contaminants (median 33, 293, and 66 ng/m3). Using improved analytical procedures at least one of the lower chlorinated congeners could be detected in 95% of the blood samples of pupils attending the contaminated school. Median concentrations for PCB 28, 52, 101, and for the sum of lower chlorinated congeners were 6, 9, 5, and 22 ng/l blood plasma, respectively, whereas the corresponding values in the control group were all < 1 ng/l. In contrast, no significant differences were found for the higher chlorinated congeners (PCB 138, 153, 180) which were detected in 1-2 orders of magnitude higher concentrations in both groups. Due to the dietary intake of these congeners similar total PCB levels were found (95th percentile 1070 and 1010 ng/l plasma in participants of the contaminated and control school). Using the Giessen Subjective Complaint List for Children and Adolescents no statistically significant differences in health complaints were observed between both groups of children. It is concluded that exposure of pupils to PCB in indoor air of the contaminated school caused increased blood concentrations of lower chlorinated congeners. Compared to background levels the detected excess body burden was very low indicating no additional health risk. Exposure was not associated to any specific subjective complaints.

Adolescent↗

PubMedDate not supplied

Contamination of individuals by radon daughters: a preliminary study.

Body radon daughter contamination reflects relative individual respiratory exposures to radon daughters; counts can be related both to household radon levels and to lung cancer risk factors such as sex and tobacco smoking. Radon daughters were counted by gamma spectroscopy from 180 adult residents of eastern Pennsylvania. A seven-position, 35-min scan was conducted in a mobile body counter, generally during afternoon or evening hours. Track-etch detectors for household radon were distributed, and were recovered from 80% of the subjects. Over 75% of the population had environmentally enhanced radon daughter contamination. House radon levels were strongly related, as anticipated, to radon daughter contamination in the 112 subjects for whom both sets of measurements were available (p less than .001); basement measurements were as strongly related to personal contamination as were living area measurements; bedroom measurements were slightly more strongly correlated. Both sex (p less than .02) and cigarette smoking (p less than .01) significantly modified the relationships, after nonlinear adjustment for travel times. Using a logarithmic model, a given house living-area radon level was associated in females with body contamination by radon daughters 2-3 times that in males. Nonsmokers had 2-4 times higher levels of contamination than smokers. Results are for the total of internal and external contamination, these being highly correlated in preliminary experiments. Time usage and activity patterns of the subjects are believed to be important in explaining these findings, and may become important variables in radon risk assessment.

Adult↗