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.

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.

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.

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)

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.

Induction of hepatic cytochrome P-450 and xenobiotic metabolizing enzymes in rats gavaged with an Alberta crude oil.

Changes in body weight gain and in biochemical parameters of blood and liver were assessed in Sprague-Dawley rats after multiple oral administration of three test doses of an Alberta crude oil (ACO). Rats treated with ACO (1.25-5 ml/kg) did not show statistically significant (p greater than .05) differences from control, corn-oil treated (5 ml/kg) rats, in body weight gains, liver weight, and blood biochemical indicators of liver (alanine aminotransferase, gamma glutamyltransferase), kidney (blood urea nitrogen, creatinine), and erythrocyte (adenosine 5'-triphosphate, 2,3-diphosphoglyceric acid, reduced glutathione) cytotoxicity. Treatment with ACO, however, caused statistically significant (p less than .05) and dose-related increases from control in (1) microsomal protein and cytochrome P-450 content, and NADPH-cytochrome c reductase, aryl hydrocarbon hydroxylase (AHH), and 7-ethoxycoumarin-O-deethylase (7-ECOD) activities, and (2) cytosolic glutathione transferase activity of liver. The induction of hepatic cytochrome P-450 and xenobiotic-metabolizing enzymes in microsomes of ACO-treated rats was probably associated with dose-related changes in isozymic forms of cytochrome P-450, as evidenced by (1) appearance of a 448-nm spectral peak in microsomes of ACO-treated rats and (2) differences in the inhibition pattern of AHH and 7-ECOD activities in microsomes of control and ACO-treated rats upon treatment with metyrapone and 7,8-benzoflavone.

Toxicoses related to the petroleum industry.

During 1977, 4,976 oil and gas wells were drilled in Oklahoma to an average depth of 4,892 feet. There were 2,253 successful oil wells and 1092 successful gas wells (26). The Oklahoma Animal Disease Diagnostic Laboratory investigated several cases where livestock in close proximity to drilling sites became ill or die. The case histories emphasize the need for a careful and complete diagnostic work-up. The identification and quantification of petroleum hydrocarbons, toxic chemicals and heavy metals in intestinal contents and tissues are diagnostically significant. The most difficult cases involve chronically ill and poor-doing animals following exposure to oil field wastes. The potential for litigation exists whenever cattle in close proximity to drilling and production sites become ill or die. Many of these cases could be prevented if livestock were prevented access to such sites by fencing or other means. The circumstantial evidence in many cases suggests the need for additional research on the toxicity of petroleum hydrocarbons, drilling muds and other oil dield wastes. Improves diagnostic methods should benefit both the livestock and oil industries.