Voglio sapere a riguardo di…

khammond on DSKJM1Z7X2PROD with RULES2

Federal Register / Vol. 86, No. 148 / Thursday, August 5, 2021 / Rules and Regulations also affect the type of equipment needed for spill response and the effectiveness of spill cleanup. Based on the experiences of cleanup efforts following the Exxon Valdez oil spill, where logistical support was readily available, spill response may be largely unsuccessful in open-water conditions.
Indeed, spill response drills have been unsuccessful in the cleanup of oil in broken-ice conditions.
Small spills of oil or waste products throughout the year have the potential to impact some bears. The effects of fouling fur or ingesting oil or wastes, depending on the amount of oil or wastes involved, could be short term or result in death. For example, in April 1988, a dead polar bear was found on Leavitt Island, northeast of Oliktok Point. The cause of death was determined to be a mixture that included ethylene glycol and Rhodamine B dye Amstrup et al. 1989.
Again, in 2012, two dead polar bears that had been exposed to Rhodamine B
were found on Narwhal Island, northwest of Endicott. While those bears deaths were clearly humancaused, investigations were unable to identify a source for the chemicals.
Rhodamine B is commonly used on the North Slope of Alaska by many people for many uses, including Industry.
Without identified sources of contamination, those bear deaths cannot be attributed to Industry activity.
During the ice-covered season, mobile, non-denning bears would have a higher probability of encountering oil or other production wastes than nonmobile, denning females. Current management practices by Industry, such as requiring the proper use, storage, and disposal of hazardous materials, minimize the potential occurrence of such incidents. In the event of an oil spill, it is also likely that polar bears would be intentionally hazed to keep them away from the area, further reducing the likelihood of impacting the population.
In 1980, Oritsland et al. 1981
performed experiments in Canada that studied the effects of oil exposure on polar bears. Effects on experimentally oiled bears where bears were forced to remain in oil for prolonged periods of time included acute inflammation of the nasal passages, marked epidermal responses, anemia, anorexia, and biochemical changes indicative of stress, renal impairment, and death.
Many effects did not become evident until several weeks after the experiment.
Oiling of the pelt causes significant thermoregulatory problems by reducing insulation value. Irritation or damage to the skin by oil may further contribute to
VerDate Sep<11>2014

17:26 Aug 04, 2021

Jkt 253001

impaired thermoregulation.
Experiments on live polar bears and pelts showed that the thermal value of the fur decreased significantly after oiling, and oiled bears showed increased metabolic rates and elevated skin temperature. Oiled bears are also likely to ingest oil as they groom to restore the insulation value of the oiled fur.
Oil ingestion by polar bears through consumption of contaminated prey, and by grooming or nursing, could have pathological effects depending on the amount of oil ingested and the individuals physiological state. Death could occur if a large amount of oil was ingested or if volatile components of oil were aspirated into the lungs. In the Canadian experiment Ortisland et al.
1981, two of three bears died. A
suspected contributing factor to their deaths was ingestion of oil.
Experimentally oiled bears ingested large amounts of oil through grooming.
Much of the oil was eliminated by vomiting and defecating; some was absorbed and later found in body fluids and tissues.
Ingestion of sublethal amounts of oil can have various physiological effects on polar bears, depending on whether the animal is able to excrete or detoxify the hydrocarbons. Petroleum hydrocarbons irritate or destroy epithelial cells lining the stomach and intestine, thereby affecting motility, digestion, and absorption.
Polar bears swimming in or walking adjacent to an oil spill could inhale toxic, volatile organic compounds from petroleum vapors. Vapor inhalation by polar bears could result in damage to the respiratory and central nervous systems depending on the amount of exposure.
Oil may also affect food sources of polar bears. Seals that die as a result of an oil spill could be scavenged by polar bears. This food source would increase exposure of the bears to hydrocarbons and could result in lethal impacts or reduced survival to individual bears. A
local reduction in ringed seal numbers as a result of direct or indirect effects of oil could temporarily affect the local distribution of polar bears. A reduction in density of seals as a direct result of mortality from contact with spilled oil could result in polar bears not using a particular area for hunting. Further, possible impacts from the loss of a food source could reduce recruitment and/or survival.
Spilled oil can concentrate and accumulate in leads and openings that occur during spring break-up and autumn freeze-up periods. Such a concentration of spilled oil would
PO 00000

Frm 00055

Fmt 4701

Sfmt 4700

43035

increase the likelihood that polar bears and their principal prey would be oiled.
To access ringed and bearded seals, polar bears in the SBS concentrate in shallow waters less than 300 m 984 ft deep over the continental shelf and in areas with greater than 50 percent ice cover Durner et al. 2004.
Due to their seasonal use of nearshore habitat, the times of greatest impact from an oil spill to polar bears are likely the open-water and broken-ice periods summer and fall, extending into the ice-covered season Wilson et al. 2018.
This scenario is important because distributions of polar bears are not uniform through time. Nearshore and offshore polar bear densities are greatest in fall, and polar bear use of coastal areas during the fall open-water period has increased in recent years in the Beaufort Sea. An analysis of data collected from the period 20012005
during the fall open-water period concluded: 1 On average approximately 4 percent of the estimated polar bears in the Southern Beaufort Sea stock were observed onshore in the fall; 2 80 percent of bears onshore occurred within 15 km 9
mi of subsistence-harvested bowhead whale carcasses, where large congregations of polar bears have been observed feeding; and 3 sea-ice conditions affected the number of bears on land and the duration of time they spent there Schliebe et al. 2006.
Hence, bears concentrated in areas where beach-cast marine mammal carcasses occur during the fall would likely be more susceptible to oiling.
Wilson et al. 2018 analyzed the potential effects of a worst case discharge WCD on polar bears in the Chukchi Sea. Their WCD scenario was based on an Industry oil spill response plan for offshore development in the region and represented underwater blowouts releasing 25,000 bbls of crude oil per day for 30 days beginning in October. The results of this analysis suggested that between 5 and 40 percent of a stock of 2,000 polar bears in the Chukchi Sea could be exposed to oil if a WCD occurred. A similar analysis has not been conducted for the Beaufort Sea;
however, given the extremely low probability i.e., 0.0001 that an unmitigated WCD event would occur BOEM 2016, Wilson et al. 2017, the likelihood of such effects on polar bears in the Beaufort Sea is extremely low.
The persistence of toxic subsurface oil and chronic exposures, even at sublethal levels, can have long-term effects on wildlife Peterson et al. 2003.
Exposure to PAHs can have chronic effects because some effects are sublethal e.g., enzyme induction or
E:FRFM05AUR2.SGM

05AUR2