| established population of blacklegged ticks with high infection prevalence for the lyme disease bacterium, borrelia burgdorferi sensu lato, on corkscrew island, kenora district, ontario. | we document an established population of blacklegged ticks, ixodes scapularis, on corkscrew island, kenora district, ontario, canada. primers of the outer surface protein a (ospa) gene, the flagellin (fla) gene, and the flagellin b (flab) gene were used in the pcr assays to detect borrelia burgdorferi sensu lato (s.l.), the lyme disease bacterium. in all, 60 (73%) of 82 adult i. scapularis, were infected with b. burgdorferi s.l. as well, 6 (43%) of 14 unfed i. scapularis nymphs were positive for ... | 2016 | 27877080 |
| prevalence of the lyme disease spirochete, borrelia burgdorferi, in blacklegged ticks, ixodes scapularis at hamilton-wentworth, ontario. | lyme disease has emerged as a major health concern in canada, where the etiological agent, borrelia burgdorferi sensu lato (s.l.), a spirochetal bacterium, is typically spread by the bite of certain ticks. this study explores the presence of b. burgdorferi s.l. in blacklegged ticks, ixodes scapularis, collected at dundas, ontario (a locality within the region of hamilton-wentworth). using passive surveillance, veterinarians and pet groomers were asked to collect blacklegged ticks from dogs and c ... | 2016 | 27226771 |
| detection of leptospira spp. in wildlife reservoir hosts in ontario through comparison of immunohistochemical and polymerase chain reaction genotyping methods. | a total of 460 kidney samples from wildlife (beavers, coyotes, deer, foxes, opossums, otters, raccoons, skunks) were obtained from road-kill and hunter/trapper donations in ontario between january 2010 and november 2012. the objectives of the study were to detect leptospira spp. by immunohistochemistry and polymerase chain reaction (pcr), to map presence of leptospires in wildlife relative to livestock and human populations, and to characterize positive samples by sequencing and comparison to le ... | 2014 | 24587507 |
| evaluating the pathogenic potential of environmental escherichia coli by using the caenorhabditis elegans infection model. | the detection and abundance of escherichia coli in water is used to monitor and mandate the quality of drinking and recreational water. distinguishing commensal waterborne e. coli isolates from those that cause diarrhea or extraintestinal disease in humans is important for quantifying human health risk. a dna microarray was used to evaluate the distribution of virulence genes in 148 e. coli environmental isolates from a watershed in eastern ontario, canada, and in eight clinical isolates. their ... | 2013 | 23377948 |
| impact of season, demographic and environmental factors on salmonella occurrence in raccoons (procyon lotor) from swine farms and conservation areas in southern ontario. | salmonella has been detected in the feces of many wildlife species, including raccoons (procyon lotor), but little is known about the epidemiology of salmonella in wildlife living in different habitat types. our objective was to investigate demographic, temporal, and climatic factors associated with the carriage of salmonella in raccoons and their environment on swine farms and conservation areas. using a repeated cross-sectional study design, we collected fecal samples from raccoons and environ ... | 2016 | 27611198 |
| spatiotemporal analysis of cryptosporidium species/genotypes and relationships with other zoonotic pathogens in surface water from mixed-use watersheds. | nearly 690 raw surface water samples were collected during a 6-year period from multiple watersheds in the south nation river basin, ontario, canada. cryptosporidium oocysts in water samples were enumerated, sequenced, and genotyped by detailed phylogenetic analysis. the resulting species and genotypes were assigned to broad, known host and human infection risk classes. wildlife/unknown, livestock, avian, and human host classes occurred in 21, 13, 3, and <1% of sampled surface waters, respective ... | 2012 | 23124241 |
| red fox as sentinel for blastomyces dermatitidis, ontario, canada. | blastomyces dermatitidis, a fungus that can cause fatal infection in humans and other mammals, is not readily recoverable from soil, its environmental reservoir. because of the red fox's widespread distribution, susceptibility to b. dermatitidis, close association with soil, and well-defined home ranges, this animal has potential utility as a sentinel for this fungus. | 2016 | 27314650 |
| detection of lyme disease bacterium, borrelia burgdorferi sensu lato, in blacklegged ticks collected in the grand river valley, ontario, canada. | we document the presence of blacklegged ticks, ixodes scapularis, in the grand river valley, centre wellington, ontario. overall, 15 (36%) of 42 i. scapularis adults collected from 41 mammalian hosts (dogs, cats, humans) were positive for the lyme disease bacterium, borrelia burgdorferi sensu lato (s.l.). using real-time pcr testing and dna sequencing of the flagellin (fla) gene, we determined that borrelia amplicons extracted from i. scapularis adults belonged to b. burgdorferi sensu stricto (s ... | 2017 | 28260991 |
| cluster analysis of campylobacter jejuni genotypes isolated from small and medium-sized mammalian wildlife and bovine livestock from ontario farms. | using data collected from a cross-sectional study of 25 farms (eight beef, eight swine and nine dairy) in 2010, we assessed clustering of molecular subtypes of c. jejuni based on a campylobacter-specific 40 gene comparative genomic fingerprinting assay (cgf40) subtypes, using unweighted pair-group method with arithmetic mean (upgma) analysis, and multiple correspondence analysis. exact logistic regression was used to determine which genes differentiate wildlife and livestock subtypes in our stud ... | 2017 | 27492809 |
| a cross-sectional study examining campylobacter and other zoonotic enteric pathogens in dogs that frequent dog parks in three cities in south-western ontario and risk factors for shedding of campylobacter spp. | an estimated 6 million pet dogs live in canadian households with the potential to transmit zoonotic pathogens to humans. dogs have been identified as carriers of salmonella, giardia and campylobacter spp., particularly campylobacter upsaliensis, but little is known about the prevalence and risk factors for these pathogens in pet dogs that visit dog parks. this study examined the prevalence of these organisms in the faeces of dogs visiting dog parks in three cities in south-western ontario, as we ... | 2014 | 23802765 |
| clinical and tree hollow populations of human pathogenic yeast in hamilton, ontario, canada are different. | yeast are among the most frequent pathogens in humans. the dominant yeast causing human infections belong to the genus candida and candida albicans is the most frequently isolated species. however, several non-c. albicans species are becoming increasingly common in patients worldwide. the relationships between yeast in humans and the natural environments remain poorly understood. furthermore, it is often difficult to identify or exclude the origins of disease-causing yeast from specific environm ... | 2014 | 24283796 |
| longitudinal study of clostridium difficile shedding in raccoons on swine farms and conservation areas in ontario, canada. | clostridium difficile is an important enteropathogen affecting humans, domestic animals, and wildlife. the objectives of this study were to 1) compare the prevalence and characteristics of c. difficile isolated from the feces of raccoons trapped on swine farms and conservation sites, and 2) investigate the role of raccoons as potential reservoirs for host-adapted strains of c. difficile using a longitudinal study. fecal swabs were collected from raccoons at 5 conservation sites and 5 swine farms ... | 2015 | 26446591 |
| detection of clostridium difficile in small and medium-sized wild mammals in southern ontario, canada. | we sampled 325 small and medium-sized wild mammals in ontario, canada in 2007 and 2010 to determine the prevalence and characteristics of clostridium difficile in wild mammals living in proximity to captive wildlife and livestock. clostridium difficile was isolated from five of 109 animals (4.6%) on four of 25 farms (16%), but was not isolated from any of the 216 samples from raccoons (procyon lotor) living on the grounds of the toronto zoo. the positive animals included two raccoons from one be ... | 2013 | 23568920 |
| prevalence and risk factors for coxiella burnetii seropositivity in small ruminant veterinarians and veterinary students in ontario, canada. | coxiella burnetii is a zoonotic pathogen that causes q fever in humans. serological and questionnaire data on c. burnetii were obtained from 32 small ruminant veterinarians and veterinary students in ontario, canada, in february 2012. overall, 59% of participants were seropositive; advanced stage of career and increased age were associated with seropositivity. | 2017 | 28373734 |
| coxiella burnetii (q fever) seropositivity and associated risk factors in sheep and goat farm workers in ontario, canada. | coxiella burnetii is a zoonotic bacterium that causes q fever, a potentially severe disease of humans. the objectives of this study were to determine the seroprevalence and risk factors for c. burnetii exposure in sheep and goat farm workers in ontario, canada. between august 2010 and march 2012, 172 farm workers from 78 sheep and goat farms were surveyed regarding demographics, lifestyle, farm practices, and medical history. sera from these people were collected and analyzed for q fever titers ... | 2016 | 27585364 |
| molecular and phylogenetic approaches for assessing sources of cryptosporidium contamination in water. | the high sequence diversity and heterogeneity observed within species or genotypes of cryptosporidium requires phylogenetic approaches for the identification of novel sequences obtained from the environment. a long-term study on cryptosporidium in the agriculturally-intensive south nation river watershed in ontario, canada was undertaken, in which 60 sequence types were detected. of these sequence types 33 were considered novel with no identical matches in genbank. detailed phylogenetic analysis ... | 2012 | 22841595 |
| detection of cyclospora, cryptosporidium, and giardia in ready-to-eat packaged leafy greens in ontario, canada. | numerous foodborne outbreaks of diarrheal illness associated with the consumption of produce contaminated with protozoan parasites have been reported in north america in recent years. the present study reports on the presence of cyclospora, cryptosporidium, and giardia in precut salads and leafy greens purchased at retail in ontario, canada. a total of 544 retail samples were collected between april 2009 and march 2010 and included a variety of salad blends and individual leafy greens. most of t ... | 2013 | 23433379 |
| an evaluation of southeastern ontario recreational water quality. | fecal contamination in recreational waters causes adverse health outcomes in humans; yet, surprisingly, a paucity of literature addresses recreational water quality in north america. the authors addressed this gap by evaluating e. coli contamination of southeastern ontario, canada, recreational beach waters between the years 2008-2011. they tested water samples for microbial contamination by the membrane filtration method. they used friedman's and repeated measures analyses of variance and descr ... | 2015 | 26058219 |
| a cross-sectional study examining the prevalence and risk factors for anti-microbial-resistant generic escherichia coli in domestic dogs that frequent dog parks in three cities in south-western ontario, canada. | anti-microbial resistance can threaten health by limiting treatment options and increasing the risk of hospitalization and severity of infection. companion animals can shed anti-microbial-resistant bacteria that may result in the exposure of other dogs and humans to anti-microbial-resistant genes. the prevalence of anti-microbial-resistant generic escherichia coli in the faeces of dogs that visited dog parks in south-western ontario was examined and risk factors for shedding anti-microbial-resis ... | 2014 | 23802858 |
| virological surveillance of influenza a subtypes isolated in 2014 from clinical outbreaks in canadian swine. | influenza a viruses (iavs) are respiratory pathogens associated with an acute respiratory disease that occurs year-round in swine production. it is currently one of the most important pathogens in swine populations, with the potential to infect other host species including humans. ongoing research indicates that the three major subtypes of iav-h1n1, h1n2, and h3n2-continue to expand in their genetic and antigenic diversity. in this study, we conducted a comprehensive genomic analysis of 16 iavs ... | 2017 | 28335552 |
| one-health simulation modelling: assessment of control strategies against the spread of influenza between swine and human populations using naadsm. | simulation models implemented using a range of parameters offer a useful approach to identifying effective disease intervention strategies. the objective of this study was to investigate the effects of key control strategies to mitigate the simultaneous spread of influenza among and between swine and human populations. we used the pandemic h1n1 2009 virus as a case study. the study population included swine herds (488 herds) and households-of-people (29,707 households) within a county in ontario ... | 2016 | 25219283 |
| one-health simulation modelling: a case study of influenza spread between human and swine populations using naadsm. | the circulation of zoonotic influenza a viruses including ph1n1 2009 and h5n1 continue to present a constant threat to animal and human populations. recently, an h3n2 variant spread from pigs to humans and between humans in limited numbers. accordingly, this research investigated a range of scenarios of the transmission dynamics of ph1n1 2009 virus at the swine-human interface while accounting for different percentages of swine workers initially immune. furthermore, the feasibility of using naad ... | 2016 | 24661802 |
| subtyping of a large collection of historical listeria monocytogenes strains from ontario, canada, by an improved multilocus variable-number tandem-repeat analysis (mlva). | listeria monocytogenes is responsible for severe and often fatal food-borne infections in humans. a collection of 2,421 l. monocytogenes isolates originating from ontario's food chain between 1993 and 2010, along with ontario clinical isolates collected from 2004 to 2010, was characterized using an improved multilocus variable-number tandem-repeat analysis (mlva). the mlva method was established based on eight primer pairs targeting seven variable-number tandem-repeat (vntr) loci in two 4-plex f ... | 2013 | 23956391 |
| macrolide-resistant mycoplasma pneumoniae in humans, ontario, canada, 2010-2011. | antimicrobial drug resistance rates for mycoplasma pneumoniae was determined in clinical specimens and isolates obtained during 2011-2012 in ontario, canada. of 91 m. pneumoniae drug-resistant specimens, 11 (12.1%) carried nucleotide mutations associated with macrolide resistance in the 23s rrna gene. none of the m. pneumoniae specimens were resistant to fluoroquinolones or tetracyclines. | 2013 | 23968896 |
| identifying an outbreak of a novel swine disease using test requests for porcine reproductive and respiratory syndrome as a syndromic surveillance tool. | animal disease monitoring and surveillance are crucial for ensuring the health of animals, humans and the environment. many studies have investigated the utility of monitoring syndromes associated with data from veterinary laboratory submissions, but no research has focused on how negative test results from a veterinary diagnostic laboratory data can be used to improve our knowledge of disease outbreaks. for example, if a diagnostic laboratory was seeing a disproportionate number of negative tes ... | 2012 | 23072647 |
| evaluating area-level spatial clustering of salmonella enteritidis infections and their socioeconomic determinants in the greater toronto area, ontario, canada (2007 - 2009): a retrospective population-based ecological study. | there have been only a few region-level ecological studies conducted in canada investigating enteric infections in humans. our study objectives were to 1) assess the spatial clustering of salmonella enterica serotype enteritidis (s. enteritidis) human infections in the greater toronto area, and 2) identify underlying area-level associations between s. enteritidis infection rates and socioeconomic status (ses) indicators that might explain the clustering of infections. | 2013 | 24237666 |
| trichinella nativa outbreak with rare thrombotic complications associated with meat from a black bear hunted in northern ontario. | although trichinellosis is known to cause thrombotic disease, serious thrombotic events are rare and have not been previously associated with trichinella nativa infection. | 2017 | 28329274 |
| a geographic study of west nile virus in humans, dead corvids and mosquitoes in ontario using spatial scan statistics with a survival time application. | surveillance of west nile virus (wnv) in ontario has included passive reporting of human cases and testing of trapped mosquitoes and dead birds found by the public. the dead bird surveillance programme was limited to testing within a public health unit (phu) until a small number of birds test positive. these dead corvid and mosquito surveillance programmes have not been compared for their ability to provide early warning in geographic areas where human cases occur each year. spatial scan statist ... | 2017 | 28220657 |
| fire, humans, and climate: modeling distribution dynamics of boreal forest waterbirds. | understanding the effects of landscape change and environmental variability on ecological processes is important for evaluating resource management policies, such as the emulation of natural forest disturbances. we analyzed time series of detection/nondetection data using hierarchical models in a bayesian multi-model inference framework to decompose the dynamics of species distributions into responses to environmental variability, spatial variation in habitat conditions, and population dynamics ... | 2014 | 24640539 |
| mapping rural community and dairy cow heat stress in southern ontario: a common geographic pattern from 2010 to 2012. | climate change has increased the occurrence of heat waves, causing heat stress among humans and livestock, with potentially fatal consequences. heat stress maps provide information about related health risks and insight for control strategies. weather data were collected throughout southern ontario, and the heat stress index (hsi) was estimated for 2010-2012. geostatistical kriging was applied to map heat stress, heat waves, and control periods. average hsi for each period ranged from 55 to 78 d ... | 2016 | 26067385 |
| prevalence of antibodies to leptospira in wild mammals trapped on livestock farms in ontario, canada. | to determine the prevalence and diversity of leptospira serogroups circulating in wildlife on farms in ontario, we tested samples from 51 raccoons (procyon lotor), seven skunks (mephitis mephitis), four rats (rattus norvegicus), and three opossums (didelphis virginiana) that were trapped on 27 livestock (swine [sus scrofa], cattle [bos taurus]) farms in 2010. seventeen of 51 raccoons (33%; 95% confidence interval [ci], 21-48%) sampled were positive for at least one leptospira serogroup using the ... | 2014 | 24807356 |
| west nile virus in ontario, canada: a twelve-year analysis of human case prevalence, mosquito surveillance, and climate data. | west nile virus (wnv) first arrived in ontario, canada in 2001 and has since spread throughout most of the province, causing disease in humans. the provincial government established a province-wide surveillance program to monitor wnv transmission throughout the 36 regional health units. here we have acquired records of wnv human and mosquito surveillance from 2002 to 2013 to describe seasonal and geographic trends in wnv activity in southern ontario. additionally, we obtained climate data from s ... | 2017 | 28829827 |
| epidemiology of salmonella on the paws and in the faeces of free-ranging raccoons (procyon lotor) in southern ontario, canada. | raccoons are common in urban and rural environments and can carry a wide range of bacteria, including salmonella, that can negatively affect human and livestock health. although previous studies have reported that raccoons shed a variety of salmonella serovars in their faeces, it is unknown whether salmonella is carried on raccoon paws. our objective was to compare the prevalence of salmonella on the paws and in the faeces of raccoons in south-western ontario. raccoons were sampled in a repeat c ... | 2016 | 26404182 |
| limited evidence of fungicide-driven triazole-resistant aspergillus fumigatus in hamilton, canada. | aspergillus fumigatus is a ubiquitous opportunistic fungal pathogen that can cause aspergillosis in humans. over the last decade there have been increasing global reports of treatment failure due to triazole resistance. an emerging hypothesis states that agricultural triazole fungicide use causes clinical triazole resistance. here we test this hypothesis in hamilton, ontario, canada, by examining a total of 195 agricultural, urban, and clinical isolates using 9 highly polymorphic microsatellite ... | 2018 | 29156151 |
| barriers, beliefs and practice patterns for breast cancer reconstruction: a provincial survey. | the purpose of this study was to characterize beliefs and practice patterns for breast cancer reconstruction among physicians who treat patients with breast cancer, in order to delineate current clinical practice. this survey was administered prior to cancer care ontario guideline publication. | 2017 | 28038321 |
| integrative analysis of the lake simcoe watershed (ontario, canada) as a socio-ecological system. | striving for long-term sustainability in catchments dominated by human activities requires development of interdisciplinary research methods to account for the interplay between environmental concerns and socio-economic pressures. in this study, we present an integrative analysis of the lake simcoe watershed, ontario, canada, as viewed from the perspective of a socio-ecological system. key features of our analysis are (i) the equally weighted consideration of environmental attributes with socioe ... | 2017 | 28002784 |
| menstrual cycle perturbation by organohalogens and elements in the cree of james bay, canada. | persistent organohalogens (pohs) and metals have been linked to alterations in menstrual cycle function and fertility in humans. the cree first nations people living near james bay in ontario and quebec, canada, have elevated levels of pohs, mercury and lead compared to other canadians. the present study examines the interrelationships between selected pohs and elements on menstrual cycle function in these cree women. menstrual cycle characteristics were derived from structured daily diaries and ... | 2016 | 26855224 |
| projecting fish mercury levels in the province of ontario, canada and the implications for fish and human health. | fish mercury levels appear to be increasing in ontario, canada, which covers a wide geographical area and contains about 250 000 lakes including a share of the north american great lakes. here we project 2050 mercury levels in ontario fish, using the recently measured levels and rates of changes observed during the last 15 years, and present potential implications for fish and human health. percentage of northern ontario waterbodies where sublethal effects of mercury on fish can occur may increa ... | 2015 | 26592742 |
| a spatial analysis of heat stress related emergency room visits in rural southern ontario during heat waves. | in southern ontario, climate change may have given rise to an increasing occurrence of heat waves since the year 2000, which can cause heat stress to the general public, and potentially have detrimental health consequences. heat waves are defined as three consecutive days with temperatures of 32 °c and above. heat stress is the level of discomfort. a variety of heat stress indices have been proposed to measure heat stress (e.g., the heat stress index (hsi)), and has been shown to predict increas ... | 2015 | 26245846 |
| using participatory epidemiology to assess factors contributing to common enteric pathogens in ontario: results from a workshop held at the ontario veterinary college, university of guelph, ontario. | common enteric pathogens that cause gastrointestinal illness are transmitted to humans through food, water or direct contact. this poses a significant concern to public health as enteric pathogens can cause disease in a large number of people, and cost a substantial amount to treat and prevent. in order to gain a better understanding of the occurrence of enteric disease in ontario, this study explored public health professionals' perceptions of major contributing factors for common enteric patho ... | 2014 | 24767430 |
| bioaccumulation of triclosan and triclocarban in plants grown in soils amended with municipal dewatered biosolids. | biosolids generally contain the microbiocidal agents triclosan (tcs) and triclocarban (tcc) that are persistent during wastewater treatment and sorp to organic material. the present study investigated the concentration of tcs in tissues of radish, carrot, and soybean grown in potted soil amended with biosolids. highest mean concentrations of tcs in radish, carrot, and soybean root tissue midway through the life cycle were 24.8 ng/g, 49.8 ng/g, and 48.1 ng/g dry weight, respectively; by the concl ... | 2014 | 24375516 |
| dietary n-nitroso compounds and risk of colorectal cancer: a case-control study in newfoundland and labrador and ontario, canada. | several n-nitroso compounds (noc) have been shown to be carcinogenic in a variety of laboratory animals, but evidence of their carcinogenicity in humans is lacking. we aimed to examine the association between noc intake and colorectal cancer (crc) risk and possible effect modification by vitamins c and e and protein in a large case-control study carried out in newfoundland and labrador and ontario, canada. a total of 1760 case patients with pathologically confirmed adenocarcinoma and 2481 popula ... | 2014 | 24160559 |
| long-term changes in fish mercury levels in the historically impacted english-wabigoon river system (canada). | the english-wabigoon river system in northwestern ontario, canada, was one of the most heavily mercury-contaminated waterways in the world due to historical discharges in the 1960s from a chlor-alkali plant. this study examines long-term (1970-2010) monitoring data to assess temporal trends in mercury contamination in walleye, northern pike and lake whitefish, three species important for sport and subsistence fishing in this region, using dynamic linear modeling and piecewise regression. for all ... | 2012 | 22785387 |
| dysregulation of cytokine response in canadian first nations communities: is there an association with persistent organic pollutant levels? | in vitro and animal studies report that some persistent organic pollutants (pops) trigger the secretion of proinflammatory cytokines. whether pop exposure is associated with a dysregulation of cytokine response remains to be investigated in humans. we studied the strength of association between plasma pop levels and circulating cytokines as immune activation markers. plasma levels of fourteen pops and thirteen cytokines were measured in 39 caucasians from a comparator sample in québec city (cana ... | 2012 | 22768323 |
| enantiospecific perfluorooctane sulfonate (pfos) analysis reveals evidence for the source contribution of pfos-precursors to the lake ontario foodweb. | exposure to perfluorooctane sulfonate (pfos) may arise directly, from emission and exposure to pfos itself, or indirectly via the environmental release and degradation of pfos-precursors. human serum enantiomer fractions (efs) of 1m-pfos have been shown to be nonracemic, suggesting that pfos-precursors are a significant source of pfos in humans, but little is known about the importance of pfos-precursors in ecosystems. in the current work, concentrations of pfos, perfluorooctane sulfonamide (pfo ... | 2012 | 22676298 |
| in vivo quantification of bone-fluorine by delayed neutron activation analysis: a pilot study of hand-bone-fluorine levels in a canadian population. | humans can be exposed to fluorine (f) through their diet, occupation, environment and oral dental care products. fluorine, at proper dosages, is believed to have positive effects by reducing the incidence of dental caries, but fluorine toxicity can occur when people are exposed to excessive quantities of fluorine. in this paper we present the results of a small pilot in vivo study on 33 participants living in southwestern ontario, canada. the mean age of participants was 45 ± 18 years with a ran ... | 2012 | 22369953 |
| "kids not rights, is their craving": sex education, gay rights, and the threat of gay teachers. | in july 1977, the ontario humans rights commission recommended adding sexual orientation to the code. this move was generally supported but toronto newspapers and evangelists sought assurances that school boards could still dismiss homosexual teachers. they demanded children be shielded from gay teachers, who they accused of sexual predation. i historically link this to a reenergized fear of homosexuals which emerged during toronto sex education debates in the 1970s. later, influenced by anita b ... | 2011 | 22214044 |
| spatiotemporal trends of mercury in walleye and largemouth bass from the laurentian great lakes region. | the risk of mercury (hg) exposure to humans and wildlife from fish consumption has driven extensive mercury analysis throughout the great lakes region since the 1970s. this study compiled fish-hg data from multiple sources in the region and assessed spatiotemporal trends of hg concentrations in two representative top predator fish species. walleye (sander vitreus) and largemouth bass (micropterus salmoides) were chosen for the trend analysis because they had more hg records (63,872) than other f ... | 2011 | 21706250 |
| estimating sediment quality thresholds to prevent restrictions on fish consumption: application to polychlorinated biphenyls and dioxins-furans in the canadian great lakes. | sediment quality thresholds (sqts) are used by a variety of agencies to assess the potential for adverse impact of sediment-associated contaminants on aquatic biota, typically benthic invertebrates. however, sedimentary contaminants can also result in elevated fish contaminant levels, triggering consumption advisories that are protective of humans. as such, sqts that would result in fish concentrations below consumption advisory levels should also be considered. to illustrate how this can be add ... | 2010 | 20872645 |
| hydroxylated polybrominated diphenyl ethers (oh-pbdes) in the abiotic environment: surface water and precipitation from ontario, canada. | hydroxylated polybrominated diphenyl ethers (oh-pbdes) have been identified as metabolites of pbdes, and also as compounds of natural origin in the marine environment; however, there has only been very limited study of their presence in the abiotic environment. in the present study, oh-pbdes were determined in samples of surface water and precipitation (rain and snow) collected from sites in ontario, canada. oh-pbdes were detected in all the samples analyzed, although half of the observed peaks ... | 2008 | 18441817 |
| pcb exposure and in vivo cyp1a2 activity among native americans. | cytochrome p-450 1a2 (cyp1a2) is an enzyme involved in the metabolic activation of some carcinogens and is believed to be induced by xenobiotics. very few studies, however, have investigated the association between environmental exposures and in vivo cyp1a2 activity in humans. to address this issue, a study was conducted of cyp1a2 activity among native americans exposed to polychlorinated biphenyls (pcbs) from the consumption of fish from the st. lawrence river. at the mohawk nation at akwesasne ... | 2005 | 15743714 |
| gastrointestinal absorption of uranium in humans. | the gastrointestinal absorption factor (f1) for uranium in humans has been determined from a study of 50 volunteers, ingesting uranium at natural levels in drinking water and food. the purpose of the study was to find an appropriate f1 value for humans to use in deriving exposure guidelines for uranium. the participants ranged in age from 13 to 87 years. they were selected from two communities: new ross, nova scotia with elevated uranium in drinking water, and ottawa, ontario with very low level ... | 2002 | 12075682 |
| nickel in the terrestrial environment. | this paper provides an overview of nickel concentrations in the terrestrial environment especially as it relates to exposure of the metal to humans and animals through food. the information includes a review of reports published in the scientific literature substantially supplemented with data obtained across the province of ontario, canada. the topics covered include background levels and levels of nickel measured in a number of different types of biota exposed to environmental contamination. t ... | 1994 | 8029689 |
| epidemiologic basis for photochemical oxidant standard. | the problem of photochemical oxidant pollution, 98% of which is ozone, is addressed. ozone itself is not the cause of all adverse effects (e.g., peroxyacetyl nitrites cause eye irritation). the typical sequence in the development of oxidant pollution is an initial increase in nitrous oxide, followed by nitrogen dioxide, followed by ozone. these pollutants can be carried long distances and may have long range effects. ozone is considered by far the most irritant gas to humans, with effects seen e ... | 1983 | 6653514 |
| quantitative interlake comparison of thyroid pathology in great lakes coho (oncorhynchus kisutch) and chinook (oncorhynchus tschawytscha) salmon. | coho salmon (oncorhynchus kisutch) and chinook salmon (oncorhynchus tshawytscha) from lakes ontario, michigan, erie, or huron were found to suffer epizootics of thyroid hyperplasia and goiters which appeared to have an environmental etiology. there were 13-fold differences in goiter prevalence within the great lakes, and the differences in goiter frequency were correlated with the degree of thyroid hyperplasia. a means of assessing the degree of thyroid hyperplasia (thyroid index) is described, ... | 1981 | 7237420 |
| ionizing radiation as an industrial health problem. | ionizing radiation, first as x-rays, later in natural form, was discovered in europe in the late 1890's. immediate practical uses were found for these discoveries, particularly in medicine. unfortunately, because of the crude early equipment and ignorance of the harmful effects of radiation, many people were injured, some fatally. because of these experiences, committees and regulatory bodies were set up to study the problem. these have built up an impressive fund of knowledge useful in radiatio ... | 1964 | 14105012 |