Barn Dust Research Articles

Recurrent airway obstruction in horses - an allergic inflammation: a review

Recurrent airway obstruction (RAO), also known as heaves, is a debilitating and incurable disease of the equine airway. Affected horses develop bronchoconstriction and neutrophilic airway inflammation as a result of exposure to specific airborne irritants and allergens such as hay mould and barn dust. Clinical signs of RAO include exercise intolerance, coughing, nostril flare and abdominal push related to respiratory effort. Evidence suggests that both the innate and acquired immune response contribute to the activation of inflammatory cells resulting in type I hypersensitivity and type III hypersensitivity reactions with an increased expression of Th1- and Th2-cytokines, chemokines, adhesion molecules, receptors and release of reactive oxygen species (ROS). The regulation of inflammatory gene expression in RAO-affected horses is dependent on the binding of transcription factors such as Nuclear factor-(kappa)B (NF-kB), activator protein-1 (AP-1) and the cyclic AMP response element binding protein (CREB) to the promoter region of target genes. In chronic disease an increased number of mucous-producing cells and increased amounts of stored mucins are observed in conjunction with other characteristics of airway tissue remodelling. In this review the findings related to the inflammatory and immunologic response in RAO-affected horses will be presented, and this information will be integrated into existing concepts of immunopathologic mechanisms.

Chloroform extract of hog barn dust modulates skeletal muscle ryanodine receptor calcium-release channel (RyR1)

Skeletal muscle weakness is a reported ailment in individuals working in commercial hog confinement facilities. To date, specific mechanisms responsible for this symptom remain undefined. The purpose of this study was to assess whether hog barn dust (HBD) contains components that are capable of binding to and modulating the activity of type 1 ryanodine receptor Ca2+-release channel (RyR1), a key regulator of skeletal muscle function. HBD collected from confinement facilities in Nebraska were extracted with chloroform, filtered, and rotary evaporated to dryness. Residues were resuspended in hexane-chloroform (20:1) and precipitates, referred to as HBDorg, were air-dried and studied further. In competition assays, HBDorg dose-dependently displaced [3H]ryanodine from binding sites on RyR1 with an IC50 of 1.5±0.1 microg/ml (Ki=0.4±0.0 microg/ml). In single-channel assays using RyR1 reconstituted into a lipid bilayer, HBDorg exhibited three distinct dose-dependent effects: first it increased the open probability of RyR1 by increasing its gating frequency and dwell time in the open state, then it induced a state of reduced conductance (55% of maximum) that was more likely to occur and persist at positive holding potentials, and finally it irreversibly closed RyR1. In differentiated C2C12 myotubes, addition of HBD triggered a rise in intracellular Ca2+ that was blocked by pretreatment with ryanodine. Since persistent activation and/or closure of RyR1 results in skeletal muscle weakness, these new data suggest that HBD is responsible, at least in part, for the muscle ailment reported by hog confinement workers.

Respiratory Issues in Beef and Pork Production: Recommendations From an Expert Panel

This paper summarizes “Respiratory Issues in Confined Feeding Operations,” a panel discussion at the Agricultural Safety and Health Council of America/National Institute for Occupational Safety and Health conference, “Be Safe, Be Profitable: Protecting Workers in Agriculture,” Dallas/Fort Worth, Texas, January 27–28, 2010. Occupational exposure to confined animal feeding operations is associated with cough, wheezing, and shortness of breath. Published data shows that 20% to 40% of hog confinement workers experience such symptoms, although most are able to continue working in this industry. Endotoxin is one component of hog barn dust that is associated with respiratory disease in workers. Endotoxin levels on cattle feedlots can also be in the range linked with occupational lung disease. The cattle industry has not yet prepared guidance documents for producers, in part because much less is known about the prevalence of lung disease in its workers. However, the pork industry provides information for pork producers on reducing their respiratory health risks through a multifaceted approach, including the use of respirators. Some jobs cannot be done safely without respiratory protection, such as entering manure pits. It is less clear for other jobs when respirators should be worn. Use of respiratory protection should be considered but not mandated for all persons working in close proximity to livestock in dusty conditions. A respiratory protection program may also serve as a cost effective biosecurity measure to protect animals from human pathogens such as influenza virus. Proper design and management of barn ventilation systems is critical for maintaining temperature and humidity levels for optimal animal growth; as well as decreasing the level of gases and respirable dusts. The pork and the cattle industries support occupational health and safety; however, the governmental guidance and recommendations for such programs are limited for the agricultural industries as a whole. The industries should lead the way in the effort to improve respiratory protection for workers. Overall, a team approach that includes input from managers, workers, and veterinarians is important for the reduction of respiratory hazards on livestock farms.

Fractionation of Swine Barn Dust and Assessment of Its Impact on the Respiratory Tract Following Repeated Airway Exposure

The effects of repeated exposure to a range of doses of swine barn dust (SBD) on airway hyperresponsiveness (AHR) and inflammation were evaluated using a mouse model system. A number of components, including endotoxin and a number of feed proteins, were identified in SBD, and mice were exposed 20 min/d for 14 d to a log dilution series of nebulized SBD suspensions. AHR to methacholine was measured using head-out whole-body plethysmography, and the methacholine concentration inducing a 20% decrease in pulmonary airflow (PC20 MCh) was calculated. At the end of the 14-d exposure period, bronchoalveolar lavage (BAL) fluids were recovered, cytokines (interleukin [IL]-1β, IL-6, keratinocyte-derived chemokine [KC], and tumor necrosis factor [TNF]) in BAL were measured by enzyme-linked immunosorbent assay (ELISA), and leukocytes in BAL were counted. The PC20 MCh was significantly lower in the group of mice that were exposed to the highest concentration of SBD than in controls or the group exposed to the lowest level of dust. Likewise, the group that was exposed to the highest level of SBD had significantly higher levels of IL-1β, KC, and TNF than controls and some other groups. There were substantially more lymphocytes and monocytes in the BAL from mice that were exposed to the higher levels of SBD for the 14-d period, but neutrophils were not a part of this response. The SBD exposures used in these experiments induced chronic inflammatory phenotype responses, as indicated by the predominance of lymphocytes and monocytes, but not neutrophils, in BAL and by inflammatory cytokines detected. The association between the PC20MCh and dose of SBD suggests that a threshold of susceptibility occurs after a relatively low, chronic exposure to SBD.

Comparison of Endotoxin and Particle Bounce in Marple Cascade Samplers With and Without Impaction Grease

ABSTRACT The health of persons engaged in agricultural activities are often related or associated with environmental exposures in their workplace. Accurately measuring, analyzing, and reporting these exposures is paramount to outcomes interpretation. This paper describes issues related to sampling air in poultry barns with a cascade impactor. Specifically, the authors describe how particle bounce can affect measurement outcomes and how the use of impaction grease can impact particle bounce and laboratory analyses such as endotoxin measurements. This project was designed to (1) study the effect of particle bounce in Marple cascade impactors that use polyvinyl chloride (PVC) filters; (2) to determine the effect of impaction grease on endotoxin assays when sampling poultry barn dust. A pilot study was undertaken utilizing six-stage Marple cascade impactors with PVC filters. Distortion of particulate size distributions and the effects of impaction grease on endotoxin analysis in samples of poultry dust distributed into a wind tunnel were studied. Although there was no significant difference in the overall dust concentration between utilizing impaction grease and not, there was a greater than 50% decrease in the mass median aerodynamic diameter (MMAD) values when impaction grease was not utilized. There was no difference in airborne endotoxin concentration or endotoxin MMAD between filters treated with impaction grease and those not treated. The results indicate that particle bounce should be a consideration when sampling poultry barn dust with Marple samplers containing PVC filters with no impaction grease. Careful consideration should be given to the utilization of impaction grease on PVC filters, which will undergo endotoxin analysis, as there is potential for interference, particularly if high or low levels of endotoxin are anticipated.

Contrasting Immunological Effects of Two Disparate Dusts – Preliminary Observations

Background: Modern lifestyle and urbanization have been associated with a raised risk for atopic diseases whereas early and long-term exposure to a farm environment confers protection against atopic sensitization. Immunomodulatory potential and microbiological characteristics of settled airborne dust from an urban house and a barn were examined. Methods: Pulmonary inflammation was induced in mice by repeated intranasal administration of dusts. Monocyte-derived human dendritic cells (moDCs) were exposed to dusts followed by coculture with purified naïve T cells. Cytokine/chemokine mRNA and protein levels were analyzed by real-time polymerase chain reaction, enzyme-linked immunosorbent assay and flow cytometry. The dusts were analyzed by cloning and sequencing of 16S rRNA genes (290 sequences) for DNA, lipids, endotoxin and β-glucan, by live-dead staining, viable counting, isolation and identification of pure cultures (n = 76). Results: Repeated exposure to house dust elicited pulmonary eosinophilia in mice whereas exposure to barn dust elicited neutrophilic and lymphocytic airway inflammation. Stimulation of moDCs with urban house dust elicited expression of Th2-promoting OX40L and Jagged-1 costimulatory molecules. Dendritic cells (DCs) exposed to house dust directed naïve T cells towards Th2 responses. Exposure of DCs to barn dust elicited the development of Th1-dominated immune responses. Urban house dust contained bacterial debris almost exclusively of human commensal species (corynebacteria, streptococci) whereas barn dust comprised mainly intact, viable bacteria of high diversity and no commensal species. Conclusion: Contact to debris originating from human commensal bacteria in urban house dust elicited a Th2-type response whereas barn dust with high bacterial diversity directed the cells towards a Th1 response.

In Vitro Production of Tumor Necrosis Factor-Alpha by Human Monocytes Stimulated with Lipopolysaccharide is Positively Correlated with Increased Blood Monocytes After Exposure to a Swine Barn

Recently there has been interest in the air quality in and around intensive livestock production facilities, such as modern swine production barns, where agricultural workers and surrounding residents may be exposed to elevated levels of organic dusts. The health effects of these exposures are not completely understood. The study that is reported here is a component of a larger investigation of the relationships among the acute effects of high-concentration endotoxin exposure (swine barn dust), polymorphisms in the TLR4 gene, and respiratory outcomes following exposure to swine confinement buildings. The relationships among a mediator of acute lung inflammation, tumor necrosis factor alpha (TNF-α), and clinical responses to acute swine barn exposure were characterized. Analysis of the results showed that in vitro stimulation of human monocytes with as little as 1 ng/ml of lipopolysaccharide (LPS) produced a significant increase in the monocytes that produced TNF-α. Although the proportion of TNF-α-positive monocytes after in vitro stimulation with 1 ng/ml of LPS was not associated with gender or TLR4 genotype, it was positively associated with the concentration of monocytes in blood after barn exposure. Thus, these two responses to different forms of LPS exposure are significantly correlated, and more responsive monocytes in vitro indicate a forthcoming relative monocytosis, post barn exposure, which may initiate a cascade of chronic inflammation.

Exposure to hog barn dust alters airway epithelial ciliary beating

Swine confinement workers are at increased risk of airway diseases, including mucus membrane irritation syndrome, chronic rhinosinusitis and chronic bronchitis. Dust extracts from swine confinement facilities stimulate the production of pro-inflammatory cytokines in bronchial epithelial cells, including interleukin (IL)-8. As IL-8 is capable of blocking beta-agonist-stimulated increases in cilia beating, which impacts on mucociliary clearance, it was hypothesised that hog barn-dust exposure might alter cilia responses to stimulation. To test this hypothesis, ciliated bovine bronchial epithelial cell cultures were exposed to hog barn-dust extract (HDE) and ciliary beat frequency (CBF) was assayed. An elevation in baseline CBF was observed. This effect appeared to be independent of endotoxin but dependent upon nitric oxide. HDE also stimulated nitric oxide production in bronchial epithelial cells; however, stimulation of cilia beating by a beta-agonist did not occur in cells pre-exposed to HDE. These data demonstrate that hog barn dust can alter normal stimulation of cilia, suggesting a mechanism for the abrogation of stimulated increases in mucociliary clearance in response to inhaled dust exposure.

Hog barn dust slows airway epithelial cell migration in vitro through a PKCα-dependent mechanism

Agricultural work and other occupational exposures are responsible for approximately 15% of chronic obstructive pulmonary disease (COPD). COPD involves airway remodeling in response to chronic lung inflammatory events and altered airway repair mechanisms. However, the effect of agricultural dust exposure on signaling pathways that regulate airway injury and repair has not been well characterized. A key step in this process is migration of airway cells to restore epithelial integrity. We have previously shown that agents that activate the critical regulatory enzyme protein kinase C (PKC) slow cell migration during wound repair. Based on this observation and direct kinase measurements that demonstrate that dust extract from hog confinement barns (HDE) specifically activates the PKC isoforms PKCalpha and PKCepsilon, we hypothesized that HDE would slow wound closure time in airway epithelial cells. We utilized the human bronchial epithelial cell line BEAS-2B and transfected BEAS-2B cell lines that express dominant negative (DN) forms of PKC isoforms to demonstrate that HDE slows wound closure in BEAS-2B and PKCepsilon DN cell lines. However, in PKCalpha DN cells, wound closure following HDE treatment is not significantly different than media-treated cells. These results suggest that the PKCalpha isoform is an important regulator of cell migration in response to agricultural dust exposure.

Settled Barn and Home Dust Induces Distinct Airway Inflammation in Mice not Explained by Endotoxin

Settled Barn and Home Dust Induces Distinct Airway Inflammation in Mice not Explained by Endotoxin

Hog barn dust extract increases macromolecular efflux from the hamster cheek pouch

The purpose of this study was to determine whether short-term exposure to an aqueous extract of hog barn dust increases macromolecular efflux from the intact hamster cheek pouch and, if so, to begin to determine the mechanism(s) underlying this response. By using intravital microscopy, we found that suffusion of hog barn dust extract onto the intact hamster cheek pouch for 60 min elicited a significant, concentration-dependent leaky site formation and increase in clearance of FITC-labeled dextran (molecular mass, 70 kDa). This response was significantly attenuated by suffusion of catalase (60 U/ml), but not by heat-inactivated catalase, and by pretreatment with dexamethasone (10 mg/kg iv) (P < 0.05). Catalase had no significant effects on adenosine-induced increase in macromolecular efflux from the cheek pouch. Suffusion of hog barn dust extract had no significant effects on arteriolar diameter in the cheek pouch. Taken together, these data indicate that hog barn dust extract increases macromolecular efflux from the in situ hamster cheek pouch, in part, through local elaboration of reactive oxygen species that are inactivated by catalase. This response is specific and attenuated by corticosteroids. We suggest that plasma exudation plays an important role in the genesis of upper airway dysfunction evoked by short-term exposure to hog barn dust.

Biomonitoring for assessment of organic dust-induced lung inflammation

Inhalation exposure to particulate matter containing endotoxin (or lipopolysaccharide (LPS)) occurs in a variety of occupations. Nasal lavage and induced sputum have been used to evaluate lung inflammation resulting from such exposures. Whole blood assay (WBA) measures cytokine production of leukocytes after ex vivo stimulation with LPS. The present study examined the effectiveness of WBA for evaluating inflammatory responses and susceptibility. C3HeB/FEJ mice were tolerised by LPS injection or sham tolerised with saline. Animals then inhaled either swine barn dust extract containing endotoxin or saline. Bronchoalveolar lavage (BAL) fluid was assayed for leukocyte counts and pro-inflammatory cytokines (interleukin-6, tumour necrosis factor-alpha). Whole blood was stimulated with 10 or 100 ng.mL(-1) of LPS, incubated for 5 or 18 h and assayed for cytokines. Barn dust-exposed groups revealed significantly higher total cells, neutrophils and cytokines in BAL compared with saline-exposed groups. Animals tolerised to LPS and exposed to barn dust demonstrated lower cellular and cytokine BAL responses. Similarly, WBA yielded significantly elevated cytokines with barn dust exposure and reduced responses with tolerisation. This study demonstrates the efficacy of whole blood assay as a biomarker of inhalation exposure to inflammatory agents and its use for assessing susceptibility to organic dust-induced lung inflammation.

Salmonella Enteritidis phage type 21 outbreak in Austria, 2005.

We report an outbreak of gastroenteritis due to Salmonella Enteritidis PT 21 associated with attending an annual traditional fair in a small Austrian village on 4 May 2005. The outbreak lasted from 4 to 8 May. Descriptive and analytical epidemiological investigations were conducted in order to determine the extent of the outbreak and to identify outbreak risk factors. Of the 115 persons who visited the fair, 85 persons fulfilled the criteria of an outbreak case (attack rate=73.9%). Stool specimens from 52 patients, including two kitchen staff, were tested for salmonella, and 20 specimens were positive for Salmonella Enteritidis PT 21. The cohort study revealed mixed salad (which included potatoes) as the likely cause of the outbreak (RR: 10.4, 95%CI 2.8 - 39.1; P=&lt;0.001). The causative agent of the outbreak was cultured from the stock of eggs used at the fair and from all three drag swabs and one barn dust sample collected from the responsible egg laying flock. Molecular subtyping by pulsed-field gel electrophoresis of genomic DNA after XbaI digestion showed that isolates from eggs, from the flock and from humans were indistinguishable. We hypothesise that cross contamination from eggs to boiled potatoes occurred in the kitchen area, where raw eggs were handled by village residents preparing a traditional Viennese egg dressing. Unrefrigerated storage of peeled potatoes may have favoured bacterial growth. Eggs from small rural flocks of laying hens kept in a traditional 'natural' way should not be assumed to be salmonella-free.

Hog barn dust extract augments lymphocyte adhesion to human airway epithelial cells.

The dust of hog confinement facilities induces airway inflammation. Mechanisms by which this dust modulates inflammation are not completely defined, although it is clear that exposure to dust can modulate both epithelial cell and inflammatory cell function. In this work, we demonstrate that airway epithelial cell (BEAS-2B) treatment with hog barn dust extract (HDE) results in augmentation of peripheral blood lymphocyte adhesion to epithelial cell cultures in vitro. The augmentation of lymphocyte adhesion to epithelial cells is dependent on the concentration of HDE and time of HDE exposure, with twofold increases observed by 3 h and maintained at 24 h. Similar results are seen with primary human bronchial epithelial cells in culture. Lymphocyte adhesion to epithelial cells is inhibited in a concentration-dependent fashion by the treatment of epithelial cells with antibody to intercellular adhesion molecule-1 (ICAM-1). In addition, HDE exposure of epithelial cells results in an approximate twofold increase in ICAM-1 expression as determined by flow cytometry analysis. Pretreatment of epithelial cells with a protein kinase C-alpha (PKC-alpha) inhibitor, Gö-6976, also inhibited subsequent lymphocyte adhesion to HDE-exposed epithelial cells. These data suggest that airway epithelial cell HDE exposure enhances subsequent lymphocyte adhesion to epithelial cells that is mediated in part by HDE modulation of ICAM-1 expression and PKC-alpha.

Bacterial DNA in House and Farm Barn Dust

Bacterial DNA in House and Farm Barn Dust

Bacterial DNA in house and farm barn dust

Background Early in life, natural exposure to microbial components (eg, endotoxin) may mitigate allergy and asthma development in childhood. Bacterial DNA is a potent stimulus for the innate immune system; its immune stimulatory potential in dust is unknown. Objectives We sought to quantify bacterial DNA and endotoxin content in dust from urban homes, rural homes, farm homes, and farm barns and to determine if dust DNA is immune-stimulatory. Methods Total DNA, bacterial DNA, and endotoxin were measured in 32 dust samples. To measure bacterial DNA content, a quantitative polymerase chain reaction assay specific for bacterial ribosomal DNA was developed. Peripheral blood mononuclear cells from 5 adults were stimulated with endotoxin-free dust DNA with/without lipopolysaccharide (LPS) from selected dust samples. IL-12p40, IL-10, and tumor necrosis factor-α were measured in cell supernatants by enzyme-linked immunosorbent assay. Results Bacterial DNA in dust correlated with endotoxin ( r = 0.56, P < .001) and total DNA content ( r = 0.51, P = .003). The highest bacterial DNA levels were measured in farm barns (mean, 22.1 μg/g dust; range, 1.3 to 56.2), followed by rural homes (6.3 μg/g; 0.2 to 20), farm homes (2.2 μg/g; 0.1 to 9.1), and urban homes (0.6 μg/g; 0.1 to 1.2). Farm barn DNA significantly potentiated ( P ≤ .05) LPS-induced IL-10 and IL-12 p40 but not tumor necrosis factor-α release (13-fold, 3-fold, and 1.5-fold increases, respectively). DNA from 6 urban homes did not demonstrate this LPS-potentiating effect. Conclusions Endotoxin is a marker for bacterial DNA, which is also higher in locales of lower asthma and allergy prevalence. DNA from farm barn dust augments the immune modulatory effects of endotoxin and may combine with exposure to other such naturally occurring microbial components to mitigate allergy and asthma development.

Immune stimulatory DNA in farm barn dust

S. R. Roy 12, A. M. Schlitz t, Y. Shen l, A. H. Liul.2; IPediatric Allergy & Clinical Immunology, National Jewish Medical & Research Center, Denver, CO, 2University of Colorado Health Sciences Center, Denver, CO. RATIONALE: Naturally occurring microbial exposures, such as endotoxin, may mitigate allergy and asthma development in childhood. Bacterial DNA is similarly a potent stimulus for the immune system, but the immune stimulatory potential of DNA in dust has not been reported. We investigated the immune stimulatory potential of DNA extracted from farm barn dust. METHODS: DNA was extracted from dust from two farm barns and one urban home using commercial DNA extraction kits and endotoxin removal columns. PBMC from 3 adult subjects were stimulated x 24 hours with endotoxin-free dust DNA_+LPS. lL-12p40, IL-10 and TNF-c~ were measured in PBMC supernatants. RESULTS: More DNA was extracted from farm barn dust (80 lag/g and 106 lttg/g dust) compared to the urban home (27 lag/g). 3 lag/ml of farm barn or urban home dust DNA alone did not stimulate cytokine release. LPS alone (300 pg/ml) stimulated PBMCs to release IL-10 (15 pg/ml), ILl2 (94 pg/ml) and TNF-ot (197 pg/ml). When combined, 3 lag/ml of farm barn DNA and LPS showed potentiation of IL-10 (363 pg/ml; 24-fold increase) and IL-12p40 (272 pg/ml; 3-fold increase) release (p<0.05), but not of TNF-ot (312 pg/ml; 1.5-fold increase). IL-10 and IL-12 release stimulated by 10 lag/ml of farm barn DNA plus 300 pg/ml of LPS approached maximal cytokine release induced by 10 ng/ml of LPS alone. CONCLUSIONS: DNA from farm barn dust augments the immune modulatory effects of endotoxin, and may combine with other naturally occurring microbial exposures to mitigate allergy and asthma development. Funding: Supported by AAAAI (ERT), National Jewish institutional fund 64 A 3-mm Wheal Doesn't Discriminate Between Cat Allergic and Non-Allergic Patients

Hog barn dust extract stimulates IL-8 and IL-6 release in human bronchial epithelial cells via PKC activation.

Hog barn workers have an increased incidence of respiratory tract symptoms and demonstrate an increase in lung inflammatory mediators, including interleukin (IL)-8 and IL-6. Utilizing direct kinase assays for protein kinase C (PKC) activation, we demonstrated that dust from hog confinement facilities, or hog dust extract (HDE), augments PKC activity of human airway epithelial cells in vitro. A 5% dilution of HDE typically stimulates an approximately twofold increase in human bronchial epithelial cell (HBEC) PKC activity compared with control medium-treated cells. This increase in PKC is observed with 15 min of HDE treatment, and kinase activity reaches peak activity by 1-2 h of HDE treatment before returning to baseline PKC levels between 6 and 24 h. The classic PKC inhibitor, calphostin C, blocks HDE-stimulated PKC activity and associated IL-8 and IL-6 release. Desensitization to HDE stimulation of PKC activation does not appear to occur because subsequent exposures to HDE after an initial exposure result in further augmentation of PKC. Detoxification of HDE with polymyxin B to remove endotoxin did not change PKC activation or IL-8 release, suggesting that endotoxin is not solely responsible for HDE augmentation of PKC. These data support the hypothesis that HDE exposure augments HBEC IL-8 and IL-6 release via a PKC-dependent pathway.

Variations in environmental contamination by polychlorinated biphenyls (PCB) and chlorinated pesticides (Lindane, DDT) on ping farms in Hodonín district in 1994 to 1999

Environmental samples (n = 216) were collected at regular intervals from 1994 to 1999 on three pig farms (D., M., T.) in the area of the district town of Hodon&amp;iacute;n, Czech Republic. The samples of feed mixtures (n = 85), drinking water (n = 44), barn dust sediments (n = 45), and muscular tissue of feeder pigs (n = 42) were analysed for the concentrations of PCB (sum of 7 indicator congeners), DDT (sum of 6 isomers), and lindane (g-hexachlorocyclohexane). The concentrations of lindane showed increasing tendencies in feed mixtures (1995&amp;ndash;1999), drinking water (1997&amp;ndash;1999), barn dust sediments (1996&amp;ndash;1998), and pork (1997&amp;ndash;1999). The limit of permissi-ble concentrations (hereinafter limit) was exceeded in two samples of feed mixtures collected in 1994. The limit for DDT was exceeded in two samples of feed mixtures collected in 1994. Generally, the concentrations showed a decreasing tendency in feed mixtures and barn dust sediments (1997&amp;ndash;1999) and regular fluctuations in pork. The limit for PCB was exceeded in two samples of feed mixtures collected in 1994 and in one sample of drink-ing water collected in 1995. The concentrations showed increasing tendencies in feed mixtures (1995&amp;ndash;1998) and pork (1996&amp;ndash;1998). Decreasing tendencies were observed in drinking water (1995&amp;ndash;1999) and barn dust sediments (1994&amp;ndash;1997). Compared with mean values for the Czech Republic, the concentrations of lindane were higher in feed samples collected in 1994, 1997, and 1998, in drinking water samples collected in 1994 and 1995, and in pork samples collected in 1994&amp;ndash;1998, the concentrations of DDT were higher in feed samples collected in 1994, 1997, and 1998, drinking water samples collected in 1995, and pork samples collected in 1994 and 1996&amp;ndash;1998, and the concentrations of PCB were higher in feed samples collected in 1997 and 1998, in drinking water samples collected in 1994 and 1995, and in pork samples collected in 1996&amp;ndash;1998. The health risk of DDT, lindane, and PCB has been assessed as moderate, medium, and moderately increased, respectively.&amp;nbsp;&amp;nbsp;

Exposure of pig fatteners and dairy cows to polycyclic aromatic hydrocarbons

Exposure of pig fatteners and dairy cows to polycyclic aromatic hydrocarbons (PAHs) was investigated by analyses of selected indoor and outdoor samples. PAH concentrations (16 U.S. EPA priority PAHs) and data on common exposure routes were used for exposure calculations.&amp;nbsp; The samples under study included water (n = 24), feed (n = 48), indoor air (n = 15), barn dust (n = 17), outdoor air (n = 6) road dust (n = 17), and soil (n = 15) collected in the summer 1999 and in the spring 2000 on 3 pig and 2 dairy cattle farms. The following mean concentrations of&amp;nbsp; 16 PAHs were found: 100 ng/l in water for pigs, 38 ng/l in water for cows, 82 &amp;micro;g/kg in feed mixtures for pigs, 128 &amp;micro;g/kg in feed concentrates for cows, 278 &amp;micro;g/kg in forages for dairy cows, 25 ng/m&lt;sup&gt;3&lt;/sup&gt; in indoor air of pig houses, 59 ng/m&lt;sup&gt;3&lt;/sup&gt; in indoor air of&amp;nbsp; cow houses, 676 &amp;micro;g/kg in dust collected in pig houses, 4 475 &amp;micro;g/kg in dust collected in cow houses, 16 ng/m&lt;sup&gt;3&lt;/sup&gt; in outdoor air of pig houses, 29 ng/m&lt;sup&gt;3&lt;/sup&gt; in outdoor air of&amp;nbsp; cow houses, 4 711 &amp;micro;g/kg in road dust collected on pig farms, 15 175 &amp;micro;g/kg in road dust collected on cattle farms, 826 &amp;micro;g/kg in soil collected around pig houses, and 1 356 &amp;micro;g/kg in soil collected around cow houses. The total intake of&amp;nbsp; 16 PAHs in the diet of cows and pigs was 14 156 &amp;micro;g and 164 &amp;micro;g PAHs per day, respectively. The exposure of cows to PAHs was 86 times higher than that of pigs. Feed was the major source of PAHs for both species (approximately 99%). Urinary 1-hydroxypyrene concentration was used as a biomarker of exposure to PAHs. The mean total amount of 1-hydroxypyrene excreted per day in porcine (2 l) and bovine (13 l) urine was 14.5 &amp;micro;g&amp;nbsp; and 1 595 &amp;micro;g, respectively, which was 3.2% and 11.9% of pyrene intake.