Effects of crude oil and diesel exposures on biochemical activities of polymorphonuclear leukocytes in cattle.

Cattle exposed to low doses of an Alberta crude oil, Pembina Cardium crude oil (PCCO), or a winter diesel oil no. 2 (WDO-2) were assessed for their biochemical activities in polymorphonuclear leukocyte (PMNL) cells (mainly neutrophils). The study used a randomized block design containing five treatment groups (8 animals/group). The animals were dosed per gavage with the test substance on study days 0, 14, 28, and 42. The dosages given (on per kg body weight) were: Group 1 (control), 10 mL/kg of potable water; Group 2, 5 mL/kg WDO-2; Group 3, 2.5 mL/kg PCCO; Group 4, 5 mL/kg PCCO; and Group 5, 10 mL/kg PCCO. Blood was collected at the specified intervals during the pre- and post-exposure periods, and the biochemical activities of isolated PMNL were analyzed. Cattle groups exposed to WDO-2 and PCCO showed moderate and statistically significant reductions (p < 0.01) in the activities of (1) phorbol myristate acetate (PMA) stimulated cellular respiration (respiratory burst), (2) NADPH-oxidase (PMA-stimulated production of superoxide anion), (3) myeloperoxidase, and (4) n-acetylglucosidase as compared to the control group. These biochemical parameters also showed statistically significant (p < 0.01) dose-related periodic (study day) trends. In general, these biochemical activities were decreased after each dosing; however, they subsequently recovered to near the pre-dosing levels. Such a biochemical response in PMNL provides a valuable biological tool to follow exposure effects in cattle accidentally exposed to low doses of petroleum hydrocarbons.

Lack of associations between air emissions from sour-gas processing plants and beef cow-calf herd health and productivity in Alberta, Canada.

This paper describes a large-scale investigation into the effects of licensed air emissions from sour-gas processing plants on the health and productivity of beef cow-calf herds in the province of Alberta, Canada. In conjunction with a geographical information system, two atmospheric-dispersion models were used to assess historical exposures at 5726 beef cow-calf farm-sites from 1987 to 1990. We did secondary analyses of health, productivity, and management data, from a government-extension survey previously administered to beef cow-calf producers across the province. Statistical models (adjusted for potential confounding and clustering within herd and over time) were used to determine associations with estimates of sour-gas emission exposure. All analyses were conducted at the herd-level. There were no significant (P>0.05) detrimental associations of exposure and the annual herd risk for culling, calf-crop delivered, calf-crop season profile, stillbirth and twinning, calfhood mortality, or calf-crop weaned.

Air emissions from sour-gas processing plants and dairy-cattle reproduction in Alberta, Canada.

The dispersion of air pollutants from all 231 licensed sour-gas processing plants in Alberta, Canada, was modeled on a monthly basis over a 10-year period (1985-1994). Exposure estimates for sulfur dioxide (SO(2)-used as a surrogate for exposure to combusted emissions) then were assigned to 1382 provincial dairy farms using a geographical-information system. Individual average and peak exposure for periods prior to each of 15 months of age and conception (four exposure-averaging periods for each of two dispersion models) were estimated for 163,988 primiparous female dairy-cattle between 1986 and 1994. Monthly or annual average farm-site exposure estimates likewise were assigned to associated herd-level data sets for the biologically relevant period of interest for each of three additional reproductive outcomes: monthly herd-average calving interval, stillbirth risk, and twinning risk. In one of the main-effects models, the maximum (i.e., peak) monthly sour-gas exposure experienced by individual-animals from birth to conception was associated with an increased time to first-calving in the very-highest exposure category (hazard ratio=0.86, 95% CI=0.80, 0.92). This equates to a decreased hazard (lambda) of calving (in each month subsequent to 22 months of age) for the highest-exposure animals (lambda=0.170) versus the zero-exposure animals (lambda=0.198) in a model with referent values for agro-ecological region and season of birth. The dose-response was not consistent across the full range of exposure categories. There was significant (P=0.003) interaction of emissions with agro-ecological region. After accounting for the interaction, a more-consistent dose-response was evident for some (but not all) agro-ecological regions. This suggests that any effect of emissions on dairy-heifer reproduction is subject to modification by features of soil type, vegetative cover, and/or climate. The increase in monthly herd-average calving interval on farms exposed to the very-highest levels of emissions appeared quite small and of limited practical importance within the range of expected exposures. There was no association between exposure and the risk for twinning. Herds exposed to higher emissions exhibited a slight decrease in risk for stillbirth.

Biochemical changes as early stage systemic biomarkers of petroleum hydrocarbon exposure in rats.

Crude and refined petroleum contain a complex mixture of aliphatic, aromatic, polyaromatic and heterocyclic hydrocarbon compounds. The objective of our research was to investigate early-stage biochemical changes in rats exposed to low dosages of petroleum hydrocarbons. The animals were repeatedly exposed, per oral by gavage, to low dosages (0.5-2.5 ml/kg) of an Alberta crude oil (ACO) and their general health and systemic biochemical parameters were assessed. Rats exposed to these doses of ACO did not show any apparent symptoms of intoxication. Similarly, no significant changes were observed in clinical parameters of systemic impairment. Systemic biochemical assessment has shown that ACO exposure caused marked changes in the activities of several cytochrome P-450 (CYP)-linked polysubstrate monooxygenase enzymes in liver, kidney and lung tissues. Exposure to ACO caused dose-dependent increases in the hepatic activities of ethoxyresorufin-O-deethylase, a CYP 1A1/A2-linked enzyme; pentoxyresorufin-O-dealkylase, a CYP 2B-linked enzyme, and ethoxycoumarin-O-deethylase, a CYP 2B/1A-linked enzyme. Temporal assessment showed that these systemic biochemical changes were reversible in nature. Analysis of biomarker chemicals provided evidence that in exposed animals petroleum hydrocarbons were mainly distributed in the adipose tissues.

Effects of multiple exposures of small doses of Pembina Cardium crude oil and diesel in rats.

In lands used for agricultural purposes, petroleum- or diesel-contaminated wastes and accidental spills of crude oil at some drilling sites pose exposure risks for occupational public, livestock, and wildlife. This study has assessed the effects of an Alberta crude oil, Pembina Cardium crude oil (PCCO), and a commercial diesel fuel #2 (CDF-2) in Sprague-Dawley rats after repeated exposures at small dose levels. Rats were given by gavage on day 1, 3, 5, and 8 specified dosages of either the control vehicle, methylcellulose (MC) (1.25 ml/kg), or PCCO (0.25-1.25 ml/kg), or CDF-2 (1.25 ml/kg). Exposure of rats to these dose levels of the test substances caused no overt symptoms of intoxication. A small but statistically significant increase in liver somatic index was observed in rats exposed to 1.25 ml/kg doses of PCCO and CDF-2; however, kidney somatic index was not significantly affected by these treatments. Blood analyses for hematological and clinical indicators of systemic impairments did not show any significant changes (p > 0.05) between the control and PCCO- or CDF-2-exposed rats. Biochemical assessment of liver and kidney tissues showed that compared to the control group, the PCCO- and CDF-2-exposed groups had a marked and significant increase (p < 0.05) in the hepatic activity of ethoxyresorufin-O-deethylase (EROD, a cytochrome P-450 [CYP] 1A1/A2-linked enzyme). In PCCO-exposed rats, the induction of EROD was dose-dependent. Exposure of rats with PCCO and CDF-2 also caused dose-related increases from the unexposed (control) or MC dosed rats in (1) hepatic activities of aryl hydrocarbon hydroxylase (AHH, a CYP 1A1-linked enzyme), ethoxycoumarin-O-deethylase (ECOD, a CYP 2B/1A-linked enzyme), glutathione transferase (GT), and NADPH-catalyzed microsomal lipid peroxidation; and (ii) ECOD activity in kidneys. The induction of hepatic CYP-linked enzymatic activities by PCCO and CDF-2 could be due to de novo synthesis of selected isoforms, as evidenced by the relative differences in the inhibition of EROD activity with 7,8-benzoflavone or metyrapone.

A review of the toxicology of air pollutants: toxicology of chemical mixtures.

On a temporal basis, air has immense capacity for moving a large mass of pollutants. Mammals and birds are exposed to pollutants in air by the inhalation (nose and mouth), cutaneous or ocular routes. Most laboratory studies on air pollutants have been limited to single air pollutants and very little research has been done on the complex mixture of compounds that exist in ambient air. Complex mixtures are further complicated by dynamic chemical reactions that occur after the emissions leave point sources. Exposure parameters are also important in the toxicity of air pollutants. Intermittent exposure of monkeys to ozone increased the adverse pulmonary effects. Superimposing spikes of 0.8 ppm nitrogen dioxide on a baseline of 0.2 ppm, as occurs on a calm winter day, increased the susceptibility of mice to bacteria-induced pneumonia. Sulfur dioxide at concentrations of 5 ppm increased pulmonary resistance by 39%. Sulfuric acid is the predominate acid particle in the atmosphere. Exposure for 1 h to > 200 micrograms sulfuric acid/m3 depressed bronchomucociliary clearance. Concentrations of 100 micrograms/m3 of photochemical products caused headaches and 510 micrograms/m3 produced cough and chest pain. For chemical interactions in dose response, nitrogen dioxide is synergistic with ozone and ammonium sulfate. When all 3 chemicals are used in mixture, the response was 340%. Atmospheric conditions, such as fog, can alter the toxicity of air pollutants. The dose response to a single chemical can be altered by chemical mixtures and pre-existing disease conditions. Understanding these relationships is important for establishing no observable adverse effect levels. Mechanisms for multiple chemical interactions are multifaceted. One chemical may interfere with the metabolism or detoxification of another. Others may interact at cell receptors. To understand the effects of multiple chemical interactions of air pollutants, there is a need for a blend of epidemiological, laboratory and field studies. Studies are expensive. In the rural agricultural settings, the economic and environmental health risks are high. Should field observations and chemical problems be used as "red flags" for action?

Hepatic and renal pathology of intraperitoneally administered microcystin-LR in rainbow trout (Oncorhynchus mykiss).

In 26 hr laboratory trials a dose of 1000 micrograms/kg microcystin-LR (MC-LR) caused 100% mortality in rainbow trout, while no mortality was observed at doses of 400 micrograms/kg or less. The liver to body mass ratio increased in fish exposed to the toxin which was likely due to water retention in the liver. In contrast to mammalian studies, hemorrhage of the liver was rare in fish. Exposure to MC-LR caused widespread hepatocellular swelling and lysis of hepatocyte plasma membranes, resulting in liquifactive necrosis (organelles floating in a milieux of cellular debris). Kidney lesions in the fish consisted of coagulative tubular necrosis with a dilation of Bowman's space. Lesions observed in the liver and kidney of fish exposed to MC-LR were considerably different than those previously reported for mammals.

Biochemical effects of Pembina Cardium crude oil exposure in cattle.

Crude oil pollution at drilling sites located within or in close proximity to agricultural pasture lands poses serious health risks to cattle raised on these lands. To investigate the clinical and systemic biochemical effects, cattle (8/group) were administered single oral doses of Pembina Cardium crude oil (PCCO) at 16.7, 33.4, and 67.4 g/kg, or water (control group) at 80 g/kg. Cattle exposed to PCCO showed dose-dependent clinical effects. At the lowest dosage, PCCO caused transient and minimal clinical effects; however, high dosages caused varied clinical signs which included tremors, nystagmus, vomiting, and pulmonary distress. On posttreatment day 7 or 30, four cattle from each treatment group were sacrificed and biochemical parameters were assayed in liver, lungs, and kidney cortex. In cattle monitored on posttreatment day 7, the PCCO-treated groups showed marked alterations from the control group in hepatic cytochrome P-450 (P-450), and in aryl hydrocarbon hydroxylase (AHH) and 7-ethoxycoumarin-O-deethylase (ECOD) activities of these tissues. Administration of PCCO caused significant increases (> 100%) in hepatic P-450, but produced variable effects on AHH and ECOD activities in each tissue. The activity of AHH was increased in all tissues; however, the effect was highest in kidney cortex (> 5000%), followed by liver (> 500%) and lungs (> 250%). The activity of ECOD was altered in a differential manner. It was either increased markedly (>1300%) in kidney cortex or increased slightly (20-30%) in liver, but decreased (> 80%) in lungs. The activities of respiratory chain enzymes (succinate-cytochrome c reductase, NADH-cytochrome c reductase and cytochrome oxidase), or NADPH-cytochrome c reductase and glutathione transferase were not changed significantly in any tissues. The alterations in P-450, AHH, and ECOD observed on day 7 were markedly reversed in cattle examined on day 30 posttreatment, indicating a recovery from induced changes. Studies in vitro with hepatic microsomal preparations from day 7 posttreatment groups showed that increases in AHH and ECOD activity in PCCO-treated cattle were due to induction of new isoforms of P-450, as evidenced by (1) the appearance of a 448-nm spectral peak, and (2) differential inhibitory effects of metyrapone and 7,8-benzoflavone on AHH and ECOD activities.

Toxicopathology of oilfield poisoning in cattle: a review.

The toxicologic pathology of petroleum and oilfield-related chemicals is reviewed, and a field guide for toxicopathologic evaluation of cattle is given. Cattle will voluntarily ingest petroleum and chemicals used in the exploration, production and transportation of crude petroleum. Variability in chemical composition of petroleum from different fields will alter the type and severity of lesions observed. When airborne pollutants are present, cattle are continually exposed and make excellent sentinel animals. The lung, kidney, liver, gastrointestinal tract, heart and brain are target organs for petroleum hydrocarbons. Exposure to elemental sulfur can produce pulmonary pathology. Sulfur-containing gases are irritating to the mucosa of the eye and respiratory tract. Arsenic and lead cause lesions in the gastrointestinal tract, brain, liver and kidney. Glycols are hepato-, nephro- and neurotoxic, and oral exposure to diethylene glycol produces corneal lesions. Invert drilling fluids are fetotoxic. Nonpesticide organophosphate esters target the peripheral and central nervous systems. Toxicopathy is a strategic tool in the diagnosis of intoxications occurring in cattle after exposure to oilfield chemicals. Cattle are sensitive to oilfield pollutants and are a useful biomonitoring species.

Toxicology of oil field pollutants in cattle: a review.

Cattle are poisoned by petroleum and substances used in drilling and operating oil and gas wells. The most common reported route of exposure for non-gaseous material is oral. Exposures occur when the petroleum or chemicals used in oil and gas field activities are available to cattle and when water and feed-stuffs are contaminated. Cattle, as a leisure activity, explore and ingest crude oil. Based on morbidity patterns in cattle herds, the amount of toxic substance ingested is variable. When water and feedstuffs are contaminated, a larger number in a herd generally are affected. Cattle have been poisoned by a wide variety of chemical mixtures. For substances high in volatile hydrocarbons, the lung is a target organ. Hydrocarbons also target the kidney, liver and brain. Exposure-linked abortions have been reported in cattle. Diethylene glycol targets the brain, liver and kidney. The reported threshold dose of unweathered oil for cattle ranges from 2.5 to 5.0 ml/kg bw, and the reported threshold dose for weathered oil is 8.0 ml/kg.

A review of nonpesticide phosphate ester-induced neurotoxicity in cattle.

Nonpesticide phosphate esters induce delayed neurotoxicity in cattle. The most common exposures are to complex mixtures of triaryl phosphate used in lubricating oils. Oral ingestion is most common, but dermal exposures have also occurred. Clinical signs of cholinesterase (ChE) inhibition may or may not be seen. Depending on the biochemical targets, the percent reduction in blood ChE is variable and can be < 30% of normal activity. Organophosphate ester-induced delayed neurotoxicity cannot be predicted by inhibition of blood ChEs. Signs of delayed neurotoxicity occur 2 to 25 d after exposure; these signs are neurologic deficiencies of the antigravity muscles and the muscles of the urinary bladder and larynx. Affected cattle may dribble urine and some may be mute. Signs of ChE inhibition generally are not observed in animals with neurological deficiencies. Pathologic findigs are axonopathy and myelin degeneration of nerves with long axons located in both the peripheral and central nervous systems. In the spinal cord, location of the affected nerve tracts is variable. Degenerative changes occur in motor neurons. Calves are less susceptible to organophosphate ester-induced delayed neurotoxicity than cows. A dose of 500 mg triaryl phosphate/kg body weight will produce complete paralysis in a mature cow in 26 d.

Evaluation of edetate and thiamine for treatment of experimentally induced environmental lead poisoning in cattle.

Twenty mature Holstein cows were randomized into 5 treatment groups. Cows of groups 2 to 5 were given 2 mg of elemental Pb/kg of body weight for 28 days. Clinical signs of plumbism were scored, and blood for Pb, progesterone, and hematologic analyses was collected weekly. Cows also were examined weekly for anomalous ovarian cycles. Starting on study day 28, cows in group 3 were treated once daily with 2 mg of thiamine HCl/kg (IM) for 13 days, cows in group 4 were treated twice daily with 62 mg of Na2,Ca-EDTA/kg (IV) for 4 days, and cows in group 5 were given thiamine (dosage regimen the same as for group 3) plus Na2,Ca-EDTA (dosage regimen the same as for group 4). On study days 96 through 139, cows were slaughtered in a commercial abattoir and samples of blood, skeletal muscles, bones, liver, and kidneys were collected and assayed for Pb concentration. Thiamine was not effective in reducing blood Pb concentration, and treatment with Na2,Ca-EDTA and thiamine plus Na2,Ca-EDTA was effective in reducing the concentration of Pb in blood. However, treatment with thiamine was more effective than treatment with Na2,Ca-EDTA or thiamine plus Na2,Ca-EDTA in inducing remission of clinical signs of plumbism. The concentration of Pb in blood was significantly (P less than 0.05) correlated to the concentration of Pb in liver, kidneys, skeletal muscles, and bones. Significant (P less than 0.05) relationship existed between number of days from Pb exposure to slaughter and concentration of Pb in blood, liver, and skeletal muscles. Exposure to Pb did not significantly alter CBC values.(ABSTRACT TRUNCATED AT 250 WORDS)

Apparent zearalenone intoxication in a dairy herd from feeding spoiled acid-treated corn.

High-moisture corn was treated with a propionic acid preservative and stored in a 40,000 bushel steel bin. This corn heated and spoiled in storage and subsequently was retreated with the preservative. The out-of-condition corn was used as an ingredient in the ration for a dairy herd of cows and replacement heifers. The finished feed was cultured for fungi and assayed for mycotoxins. Results were 750,000 Fusarium spp colonies/g of feed, and 1.5 mg zearaleonone and 1.0 mg deoxynivalenol/kg of feed. Frequent episodes of behavioral estrus of 2 to 5 d duration, that were not synchronized with the ovarian cycle, were observed. Cows in the second and third trimester of pregnancy also has episodes of behavioral estrus. Idiopathic vaginitis was diagnosed. Mammary development occurred in the prepubertal heifers. Cows bred in true estrus were found in true estrus 35 to 55 d later. All of the heifers with precocious mammary development were subsequently culled from the herd because of sterility.

Observations on PCBs and mercury in common loons (Gavia immer) collected from southwestern Lake Michigan.

The death of common loons (Gavia immer) was associated with a small spill of bunker-C oil off the Chicago shoreline of Lake Michigan. Petroleum oil was not found on the feathers or in the lungs of the birds. Botulinus toxins C and E were found in heart blood. Because the carcasses were autolysed, botulism toxins could have been produced postmortem. An average of 97 micrograms PCBs (Aroclor 1254 standard) and 2.2 micrograms dieldrin/g of body fat also were found. Concentrations of heavy metals in one bird were 0.25 microgram of total mercury and 0.5 microgram of lead/g of liver, respectively. The loons had abundant body fat suggesting they were not debilitated at the time of death.

Effects of hydrogen sulfide exposure on lung mitochondrial respiratory chain enzymes in rats.

Fischer-344 rats were exposed for 4 hr to various concentrations of hydrogen sulfide (H2S) gas and killed either immediately or at 1, 24, or 48 hr after exposure. Mitochondrial fractions from lung tissues were assayed for the activities of respiratory chain enzymes. Exposure of rats to a low concentration (10 ppm) of H2S caused no significant changes in the activities of lung mitochondrial enzymes. However, exposure to sublethal concentrations of H2S (50-400 ppm) produced marked and highly significant depressions in the activities of cytochrome c oxidase and succinate oxidase complexes of the respiratory chain. The inhibition of cytochrome c oxidase activity in lungs was most severe (greater than 90%) in rats that died from acute exposure to greater than 500 ppm H2S. In rats exposed to 200 and 400 ppm H2S, a marked recovery in cytochrome c oxidase activity of lungs was observed at 24 and 48 hr postexposure. Studies in vitro with rat lung mitochondria showed that low concentrations of sulfide also caused a similar and selective inhibition of cytochrome c oxidase activity. This effect was reversed upon removal of sulfide either by washing or by oxidation with methemoglobin. The nature of sulfide inhibition of cytochrome c oxidase was noncompetitive with respect to ferrocytochrome c. Because the activities of NADH-cytochrome c reductase and succinate-cytochrome c reductase were not significantly altered by H2S exposure and in vitro treatments with low concentrations of sulfide, it is concluded that under physiological conditions H2S would block the respiratory chain primarily by inhibiting cytochrome c oxidase. Such a biochemical impairment would lead to functional (histotoxic) hypoxia in the lung tissues.

Effects of dichlorvos on blood cholinesterase activities of cattle.

Inhibitory effects of dichlorvos (2,2-dichlorovinyl dimethyl phosphate, DDVP) [corrected] on erythrocyte acetylcholinesterase (AChE) and plasma cholinesterase (ChE) activities of steers were characterized after treatments in vitro and in vivo (cutaneous application). The rates of in vitro inhibition were markedly influenced by DDVP concentration and incubation time. The activities of inhibited enzymes failed to reactivate spontaneously and had little response to treatment with 2-pyridine aldoxime methiodide (2-PAM). After gel-filtration chromatography, however, the inhibited enzymes had remarkable spontaneous reactivation and reactivation by 2-PAM treatment, indicating interference of excess unreacted DDVP in the reactivation process. Repeated cutaneous applications of a DDVP-containing livestock spray caused marked and characteristic decreases of AChE and ChE activities in blood of treated steers; however, the effects were transient because activities of both enzymes regenerated gradually. The nature of these in vivo trends suggests that spontaneous and de novo synthetic mechanisms could be responsible for complete recovery of both enzyme activities.

Acute aflatoxicosis in feeder pigs, resulting from improper storage of corn.

Aflatoxicosis was diagnosed in 600 feeder pigs, of which 400 died, 150 were destroyed, and 50 were marketed. The pigs were exposed to 2,500 to 3,500 micrograms of aflatoxins/kg of feed. Drought-stressed damaged corn infected with Aspergillus flavus was stored under ambient conditions in a glass-lined silo, and this storage environment provided conditions that favored rapid fungal growth and mycotoxin production.

Hematologic changes induced by intravenous administration of diacetoxyscirpenol in pigs, dogs, and calves.

Diacetoxyscirpenol (DAS) was given IV to pigs (0, 0.5, and 1.0 mg/kg of body weight), cattle (0 and 0.5 mg/kg), and dogs (0 and 0.5 mg/kg). Blood was collected and hemograms were done at 0.5-hour intervals for 8 hours. The animals were euthanatized at 8 hours after treatment, and bone marrow samples were taken and examined by light microscopy. Moderate to severe necrosis of bone marrow hematopoietic elements was found in animals given DAS. The sequential increase in the type and number of abnormal cells in the blood suggested a successive destruction of the hematopoietic elements. A marked left shift in the neutrophil population was found in animals given DAS. Metarubricytes and large platelets were found in the blood of animals given DAS. Lymphocytes were replaced with immature cells. Pathologic changes were most severe in the pigs given a dosage of 1.0 mg of DAS/kg. The order of species sensitivity to DAS was pigs greater than dogs much greater than cattle.

Cutaneous ergotism in a herd of dairy calves.

Weather conditions in northern Illinois favored infection of pasture grasses with Claviceps purpurea. A herd of 52 Holstein heifers selectively grazed the seedheads of an orchard grassbromegrass pasture infected with C purpurea and were poisoned. Peptide alkaloids were found in the sclerotia. Clinical signs of intoxication included lameness, edema of the hind limbs, epilation, areas of skin necrosis, and diarrhea. Pathologic findings included myopachynsis of arterioles in the deep dermal areas, lungs, kidney, spleen, submucosa of small intestines and cerebral cortex, focal cracks on the hoofs, and multifocal areas of detachment of the hoof wall. Of the 52 heifers, 3 died on the farm, 1 was euthanatized, and 3 were sold. The remaining heifers conceived without difficulty, and subsequent calvings were uncomplicated.