Pollution is the introduction of contaminants into the environment that causes adverse change. For the purpose of this review, pollution is synonymous with acute and chronic events that release notable/reportable quantities of chemicals or substances into the environment. Exposure to industrial chemicals as well as to natural substances released into the marine environment is a potential health threat for CI belugas and their prey. For an in-depth review of available information on this topic, see Appendix IX.G – CI Beluga Pollution and Contaminants Supplement.

Sources and Types of Pollution in Cook Inlet

A number of sources of chemical and biological pollution have been identified in and around Cook Inlet, but a comprehensive water quality survey of Cook Inlet is not available. Potential sources of pollution which could affect CI belugas include: offshore oil and gas development; municipal waste and bilge discharge; marine oil spills; runoff from roads, airport, military sites, mines, construction sites, and farms; terrestrial and marine spills of contaminants other than oil; resuspension of contaminants through dredging; ship ballast discharge; watercraft exhaust and effluent; coal transportation and burning; auto exhaust; antifouling paint; and trash. Possible contaminants CI belugas could be exposed to include: persistent organic pollutants; aromatic hydrocarbons; chlorinated hydrocarbons; heavy metals; endocrine disruptors; pharmaceuticals; antibiotics; sanitizers; disinfectants; detergents; insecticides; fungicides; and de-icers. While NMFS has some data about levels of traditionally studied contaminants in CI belugas (e.g., Dichlorodiphenyltrichloroethane [DDT], polychlorinated biphenyls [PCBs], polycyclic aromatic hydrocarbons [PAHs], etc.), virtually nothing is known about other emerging pollutants of concern and their effects on CI belugas. The emerging pollutants of concern include endocrine disruptors (substances that interfere with the functions of hormones), pharmaceuticals, personal care products (chemicals such as soaps, fragrances, insect repellants, etc.), prions (infectious proteins that cause neurodegenerative disease), and other bacterial and viral agents that are found in wastewater and biosolids.

URS (2010) evaluated the level of potential concern (probable, possible, unlikely) to CI belugas from various classes of chemicals. Chemicals identified by URS (2010) to be of probable and possible concern and for which at least some data are available for either CI belugas or other beluga populations are described in Table 8. URS (2010) categorized the following chemicals as unlikely to be of potential concern for CI belugas: hydrocarbons (other than PAH compounds), glycols, diagnostic agents, dietary supplements, personal care products, engineered particles (<100 nanometers), or prions. Acute effects associated with oil spills and natural gas blowouts are considered in the threat type Catastrophic Events.

Table 8. Compounds of probable and possible concern for CI belugas, for which data are available either for CI belugas or for other beluga populations.
Chemical Class
Example Individual Constituents
Level of concern for CI Beluga
CI beluga data
Other beluga data
Chlorinated pesticides Many banned in the U.S. in the 1970s, but are still used in other parts of the world: DDTs, aldrin, dieldrin, chlordane, endosulfan, mirex, toxaphene mixtures Probable Yes Yes
Chlorinated dielectric fluids, transformer oils Banned in the U.S. since the 1970s, but previously used as coolants and lubricants in transformers and other electrical equipment. 209 PCB congeners, aroclor mixtures Probable Yes Yes
Chlorinated dibenzo-p-dioxins and furans Not intentionally used; byproduct emitted from waste incinerators, chlorinated bleaching, wood preservation, chemical synthesis. 75 Dioxin congeners (PCDDs), 135 furan congeners (PCDFs) Probable No Yes
Metals Methyl mercury, selenium, butyltins, cadmium, arsenica, leada, manganesea, mercurya, organic tina Probable Yes Yes
Aryl and Polycyclic aromatic hydrocarbons (PAHs) This is naturally occurring and also released from industrial products (asphalt, coal tar) and combustion of coal, oil, gas, wood, or organic waste. Of major concern are: Benzo(a)pyrene, anthracene, pyrene, toluenea, benzenea, xylenea Probable No Yes
Polybrominated flame retardants Commonly used as flame retardants in computers, textiles, construction, and electrical equipment. Polybrominated diphenylethers (PBDEs) (PBBs, polybrominated biphenyls are no longer produced in the U.S.) Possible Yes Yes
Perfluorinated Compounds Commonly used as a water and oil repellant, protective coatings in food packaging, textiles, and carpeting: Teflon coating, Perfluorooctane sulfonates, Perfluorooctanoic acid Possible Yes No

a Denotes compounds with known ototoxic (i.e., damaging to hearing) effects.

Source: Modified and reproduced with permission from URS 2010, Table 5, and the factsheets.

Relative Concern

Pollution occurs rangewide with localized hotspots throughout the CI belugas’ habitat, at variable frequencies depending on the source of the pollution. Point source pollution enters the water from a specific source (e.g., a sewage outfall pipe; in-water construction site; etc.); these sources of pollution may result in localized effects. Non-point sources of pollution in Cook Inlet occur over broader geographic areas that can ultimately have rangewide effects (e.g., runoff from roads, airports, agricultural sites, military training areas, etc.). Individually and collectively, point and non-point source pollutants may have either local or widespread effects, depending upon the location, size and abundance of the outfall sites, time of release, tidal conditions at the point(s) of release, and characteristics of the pollutant(s).

The amount of pollution entering Cook Inlet is likely increasing as the regional human population grows, a trend that is likely to continue. However, upgrading the Asplund Wastewater Treatment Facility, currently Alaska’s largest wastewater treatment facility, from a primary to a secondary treatment facility could make a notable difference in total pollutants released into Cook Inlet, particularly into Cook Inlet beluga whale critical habitat. The decision of whether to upgrade this facility is currently under review by the Environmental Protection Agency (EPA).

Exposure to contaminants found in pollution may be the result of CI belugas’ direct contact with contaminants found in the water; inhalation of contaminants in the air; or ingestion of contaminants found in prey, mud, or silt. It is also possible that adult males may have higher levels of contaminants stored in the body than do adult females because females may have the ability to transfer some of their contaminant load to their calves during pregnancy and lactation. There is little information on the potentially deleterious effects of contaminants on CI belugas; but it is likely that chronic exposure to contaminants may compromise an individual whale’s health, with the potential for population-level impacts.

For the contaminants that have been studied, CI belugas generally had lower contaminant loads than did belugas from other populations (Becker et al. 2000, Lebeuf et al. 2004, NMFS 2008a, Becker 2009, DFO 2012, Reiner et al. 2011, Wetzel et al. 2010, Hoguet et al. 2013). Based on these results, it is possible that the levels of pollution in Cook Inlet, the exposure to pollution by CI belugas, or the rate of uptake/retention of contaminants by CI belugas, is lower than that for other beluga populations. The more temperate habitat of CI belugas compared to belugas residing at higher latitudes may help explain why persistent organic pollutants are not as prevalent in whales living in Cook Inlet. 22 Additionally, chemical analyses of water and dredging sediments from Cook Inlet found that contaminants analyzed were below management levels, and some were below detection limits (Frenzel 2002; U.S. Army Corps of Engineers [Corps] 2003).

The available information suggests that the magnitude of the pollution threat to CI belugas appears low, although not all pollutants to which these whales are exposed have been studied in this environment. Even though the existing studies are not comprehensive of all possible contaminants to which belugas may be exposed, the comparatively low levels of contaminants documented in CI belugas themselves as well as in the Cook Inlet water and sediment samples analyzed suggest that the relative concern of these known and tested contaminants to CI belugas is most likely low.