Summary
Domestic and wild animals are exposed to crude petroleum, refined petroleum, and chemicals used by the petroleum industry by the oral, inhalation, and dermal routes of exposure. Crude and refined petroleum are complex chemical mixtures and present unique toxicology. The interface between the petroleum industry and other land uses can bring animal production, human habitation, and wildlife in close proximity to each other. Petroleum waste produced in the oil fields can be exempt from hazardous waste regulations. Substances of various types, often considered trade secrets for which limited toxicologic data are available, can be used in drilling, fracking, producing, and reworking oil and gas wells. Contamination of surface and groundwater by the petroleum industry can occur. Sour petroleum contains sulfur compounds. The production of sour liquid and sour gaseous petroleum presents risk of exposure to various sulfur compounds. Produced water can have unique ion profiles, can be high in total dissolved solids, and can present a hazard to domestic and wild animals. Animals will ingest petroleum, and fenced-in animals cannot escape gaseous emissions.
Introduction
This chapter primarily discusses the toxicology of crude petroleum and pollution generated during the production of petroleum. Emphasis is placed on domestic animals. Domestic and wild animals can also be exposed to environmental petroleum. Crude petroleum can be released into the environment during well blowouts, leaks at wellheads, pipeline leaks, land and sea shipping disasters, and other events and activities. Emissions can be from venting storage tanks, blowouts of gas wells, burning petroleum that has been spilled, or burning unwanted gaseous material. Production of crude petroleum presents two major toxicological issues: exposure of animals to the primary raw product and exposure to pollution generated by the production of crude petroleum. Crude petroleum is designated as sweet or sour based on sulfur content, primarily hydrogen sulfide (H2S). Sour petroleum, especially sour gas, is an economic source of sulfur sold as a commodity. Some governments exempt waste generated in oil fields from hazardous waste regulations. In many geographic regions, such as western Canada, the provincial governments own the majority of mineral resources and can require landowners to provide land leases for oil and gas exploitation. Uneconomical products such as gas including H2S coming from crude oil and bitumen can be piped to a flare pipe and burned or vented into the atmosphere. Domestic and wild animals are exposed to pollution from oil and gas activity. Issues exist in using agricultural lands for waste disposal and food production. Oil pits also present a risk for wildlife (Trail, 2006). Oil pits contain waste fluids that may be stored in pits, open tanks, and other sites accessible to wildlife and domestic animals.
Intoxication of animals with crude and refined petroleum does occur. The two major conditions for exposure are spills and leaks of petroleum into aquatic and terrestrial systems. There is an agricultural and petroleum industrial interface from multiple use of lands for agricultural and petroleum production. Land located in remote regions of the world is also used for oil and gas production. Land uses by the petroleum industry include oil and gas well sites, tank battery sites, gathering sites, sweet and sour gas plants, compressor stations, and pipelines. Crude petroleum and chemicals used in the oil fields can be spilled. The dermal, inhalation, and oral routes of exposure can subsequently poison domestic and wild animals. Birds and mammals can have oil soiling their feathers and fur, respectively. Oral ingestion also occurs from dermal exposure and during preening. Loss of insulation protection of feathers and fur can lead to hypothermia. Oil and gas field operations have intentional and unintentional air emissions. The production of sour gas and the removal of sulfur (sour gas processing plants) present toxicology issues. Animals are poisoned when petroleum products are used as medicaments, containers containing petroleum products are used for animal feedstuffs and applications of parasiticides, petroleum containers are left open and unattended, and domestic spills occur during transportation and use. Water can accompany gas and oil to the surface. This is commonly referred to as production water, and it can be high in brine and salt poisoning can occur. Abandoned oil and gas wells can seep petroleum and brine water to the surface.
Oil and gas well drilling and completing
Drilling
Oil and gas wells are drilled into oil- and gas-producing formations that exist at varying depths below the surface. During drilling operations, drilling fluids are used to cool and lubricate the drill bit, support the walls of the borehole, and move the cuttings to the surface. The weight of the drilling fluid (mud) controls subsurface pressure and aids in preventing blowouts. Different types of drilling fluids and additives are used for drilling the different geologic zones and penetrating the formation. There are different preferences for the composition of drilling fluids, cost considerations, and requirements of the drilling techniques employed. Wide variations in the chemical composition of drilling fluids are found when companies are drilling within the same oil field (Edwards and Gregory, 1991). Drilling and petroleum companies can be reluctant to disclose substances added to drilling fluids.
Two basic types of drilling fluids used are the water-based drilling fluid and the non-aqueous drilling fluids. Water-based drilling fluids generally consist of salts, bentonite clay, and barium sulfate for density, and other chemicals are added to give desired properties such as lubrication and reduction of foaming (Table 61.1). Brine or freshwater can be used in water-based drilling fluids. Lignite or lignosulfonate, caustic chrome salts, and other compounds (for example, starches and cellulosic polymer) may also be used. In the non-aqueous drilling fluids (invert drilling fluids), freshwater or brine water is emulsified in a hydrocarbon phase. Emulsifiers are used to disperse the water in the hydrocarbons. The water emulsion is generally less than 1 µm in diameter. Diesel fuel is often used as the hydrocarbon in land-based drilling operations. Hydrotreated mineral oil can be used, which has a low content of polyaromatic hydrocarbons. Synthetic hydrocarbons and polymers can also be used. Drilling mud can also contain heavy metals, especially aluminum, cadmium, chromium including chromates, copper, iron, lead, mercury, and zinc. Drilling wastes are representative of the formations encountered during the drilling operations. If radioactive materials are encountered in the formations, radioactive materials and gas can be in drilling fluids and drill cuttings.
Summary
Domestic and wild animals are exposed to crude petroleum, refined petroleum, and chemicals used by the petroleum industry by the oral, inhalation, and dermal routes of exposure. Crude and refined petroleum are complex chemical mixtures and present unique toxicology. The interface between the petroleum industry and other land uses can bring animal production, human habitation, and wildlife in close proximity to each other. Petroleum waste produced in the oil fields can be exempt from hazardous waste regulations. Substances of various types, often considered trade secrets for which limited toxicologic data are available, can be used in drilling, fracking, producing, and reworking oil and gas wells. Contamination of surface and groundwater by the petroleum industry can occur. Sour petroleum contains sulfur compounds. The production of sour liquid and sour gaseous petroleum presents risk of exposure to various sulfur compounds. Produced water can have unique ion profiles, can be high in total dissolved solids, and can present a hazard to domestic and wild animals. Animals will ingest petroleum, and fenced-in animals cannot escape gaseous emissions.
Introduction
This chapter primarily discusses the toxicology of crude petroleum and pollution generated during the production of petroleum. Emphasis is placed on domestic animals. Domestic and wild animals can also be exposed to environmental petroleum. Crude petroleum can be released into the environment during well blowouts, leaks at wellheads, pipeline leaks, land and sea shipping disasters, and other events and activities. Emissions can be from venting storage tanks, blowouts of gas wells, burning petroleum that has been spilled, or burning unwanted gaseous material. Production of crude petroleum presents two major toxicological issues: exposure of animals to the primary raw product and exposure to pollution generated by the production of crude petroleum. Crude petroleum is designated as sweet or sour based on sulfur content, primarily hydrogen sulfide (H2S). Sour petroleum, especially sour gas, is an economic source of sulfur sold as a commodity. Some governments exempt waste generated in oil fields from hazardous waste regulations. In many geographic regions, such as western Canada, the provincial governments own the majority of mineral resources and can require landowners to provide land leases for oil and gas exploitation. Uneconomical products such as gas including H2S coming from crude oil and bitumen can be piped to a flare pipe and burned or vented into the atmosphere. Domestic and wild animals are exposed to pollution from oil and gas activity. Issues exist in using agricultural lands for waste disposal and food production. Oil pits also present a risk for wildlife (Trail, 2006). Oil pits contain waste fluids that may be stored in pits, open tanks, and other sites accessible to wildlife and domestic animals.
Intoxication of animals with crude and refined petroleum does occur. The two major conditions for exposure are spills and leaks of petroleum into aquatic and terrestrial systems. There is an agricultural and petroleum industrial interface from multiple use of lands for agricultural and petroleum production. Land located in remote regions of the world is also used for oil and gas production. Land uses by the petroleum industry include oil and gas well sites, tank battery sites, gathering sites, sweet and sour gas plants, compressor stations, and pipelines. Crude petroleum and chemicals used in the oil fields can be spilled. The dermal, inhalation, and oral routes of exposure can subsequently poison domestic and wild animals. Birds and mammals can have oil soiling their feathers and fur, respectively. Oral ingestion also occurs from dermal exposure and during preening. Loss of insulation protection of feathers and fur can lead to hypothermia. Oil and gas field operations have intentional and unintentional air emissions. The production of sour gas and the removal of sulfur (sour gas processing plants) present toxicology issues. Animals are poisoned when petroleum products are used as medicaments, containers containing petroleum products are used for animal feedstuffs and applications of parasiticides, petroleum containers are left open and unattended, and domestic spills occur during transportation and use. Water can accompany gas and oil to the surface. This is commonly referred to as production water, and it can be high in brine and salt poisoning can occur. Abandoned oil and gas wells can seep petroleum and brine water to the surface.
Oil and gas well drilling and completing
Drilling
Oil and gas wells are drilled into oil- and gas-producing formations that exist at varying depths below the surface. During drilling operations, drilling fluids are used to cool and lubricate the drill bit, support the walls of the borehole, and move the cuttings to the surface. The weight of the drilling fluid (mud) controls subsurface pressure and aids in preventing blowouts. Different types of drilling fluids and additives are used for drilling the different geologic zones and penetrating the formation. There are different preferences for the composition of drilling fluids, cost considerations, and requirements of the drilling techniques employed. Wide variations in the chemical composition of drilling fluids are found when companies are drilling within the same oil field (Edwards and Gregory, 1991). Drilling and petroleum companies can be reluctant to disclose substances added to drilling fluids.
Two basic types of drilling fluids used are the water-based drilling fluid and the non-aqueous drilling fluids. Water-based drilling fluids generally consist of salts, bentonite clay, and barium sulfate for density, and other chemicals are added to give desired properties such as lubrication and reduction of foaming (Table 61.1). Brine or freshwater can be used in water-based drilling fluids. Lignite or lignosulfonate, caustic chrome salts, and other compounds (for example, starches and cellulosic polymer) may also be used. In the non-aqueous drilling fluids (invert drilling fluids), freshwater or brine water is emulsified in a hydrocarbon phase. Emulsifiers are used to disperse the water in the hydrocarbons. The water emulsion is generally less than 1 µm in diameter. Diesel fuel is often used as the hydrocarbon in land-based drilling operations. Hydrotreated mineral oil can be used, which has a low content of polyaromatic hydrocarbons. Synthetic hydrocarbons and polymers can also be used. Drilling mud can also contain heavy metals, especially aluminum, cadmium, chromium including chromates, copper, iron, lead, mercury, and zinc. Drilling wastes are representative of the formations encountered during the drilling operations. If radioactive materials are encountered in the formations, radioactive materials and gas can be in drilling fluids and drill cuttings.
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