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PAHs

Sediment

PAHs (µg/kg dry weight)

Mussels

PAHs (µg/kg wet weight)
North
296.992 µg/kg
296.992 µg/kg
Metlakatla
44.081 µg/kg
44.081 µg/kg
161775 µg/kg
161775 µg/kg
Prince Rupert
546.007 µg/kg
546.007 µg/kg
732.062 µg/kg
732.062 µg/kg
Wiah Point
3.598 µg/kg
3.598 µg/kg
348.018 µg/kg
348.018 µg/kg
Armentieres Channel
7.685 µg/kg
7.685 µg/kg
312.117 µg/kg
312.117 µg/kg
Bischof Islands
9.227 µg/kg
9.227 µg/kg
240.304 µg/kg
240.304 µg/kg
Haswell Bay
7.076 µg/kg
7.076 µg/kg
607.388 µg/kg
607.388 µg/kg
Louscoone Inlet
22.918 µg/kg
22.918 µg/kg
81.5079 µg/kg
81.5079 µg/kg
Bella Bella
9.364 µg/kg
9.364 µg/kg
177.915 µg/kg
177.915 µg/kg
Port Neville
7.927 µg/kg
7.927 µg/kg
36.162 µg/kg
36.162 µg/kg
Sechelt
Not sampled
912.048 µg/kg
912.048 µg/kg
Strait of Georgia 1
Not sampled
1193.05 µg/kg
1193.05 µg/kg
Strait of Georgia 2
Not sampled
97.138 µg/kg
97.138 µg/kg
Howe Sound 1
Not sampled
103.12 µg/kg
103.12 µg/kg
Howe Sound 2
27.496 µg/kg
27.496 µg/kg
2627.42 µg/kg
2627.42 µg/kg
Howe Sound 3
692.808 µg/kg
692.808 µg/kg
730.656 µg/kg
730.656 µg/kg
Indian Arm 1
71.786 µg/kg
71.786 µg/kg
345.679 µg/kg
345.679 µg/kg
Indian Arm 2
132.707 µg/kg
132.707 µg/kg
7721.45 µg/kg
7721.45 µg/kg
Burrard Inlet 1
137.035 µg/kg
137.035 µg/kg
6116.92 µg/kg
6116.92 µg/kg
Burrard Inlet 2
Not sampled
412.527 µg/kg
412.527 µg/kg
Burrard Inlet 3
139.482 µg/kg
139.482 µg/kg
679.12 µg/kg
679.12 µg/kg
Burrard Inlet 4
Not analyzed
15570.6 µg/kg
15570.6 µg/kg
Burrard Inlet 5
Not sampled
15137.3 µg/kg
15137.3 µg/kg
Burrard Inlet 6
172.616 µg/kg
172.616 µg/kg
6540.04 µg/kg
6540.04 µg/kg
Burrard Inlet 7
Not sampled
4352.01 µg/kg
4352.01 µg/kg
Burrard Inlet 8
41.635 µg/kg
41.635 µg/kg
Not sampled
Burrard Inlet 9
40.487 µg/kg
40.487 µg/kg
2234.04 µg/kg
2234.04 µg/kg
Burrard Inlet 10
108.653 µg/kg
108.653 µg/kg
1663.5 µg/kg
1663.5 µg/kg
Burrard Inlet 11
Not sampled
10502.4 µg/kg
10502.4 µg/kg
Burrard Inlet 12
Not sampled
4144.17 µg/kg
4144.17 µg/kg
Burrard Inlet 13
Not sampled
11945.1 µg/kg
11945.1 µg/kg
Burrard Inlet 14
Not sampled
Not sampled
Burrard Inlet 15
56.306 µg/kg
56.306 µg/kg
257.981 µg/kg
257.981 µg/kg
Fraser River 1
29.462 µg/kg
29.462 µg/kg
196.132 µg/kg
196.132 µg/kg
Fraser River 2
Not sampled
423.123 µg/kg
423.123 µg/kg
Fraser River 3
Not sampled
751.269 µg/kg
751.269 µg/kg
Fraser River 4
Not sampled
1049.73 µg/kg
1049.73 µg/kg
Fraser River 5
Not sampled
Not sampled
Fraser River 6
46.024 µg/kg
46.024 µg/kg
Not sampled
Fraser River 7
35.825 µg/kg
35.825 µg/kg
14675.4 µg/kg
14675.4 µg/kg
Tsawwassen
Not sampled
130.222 µg/kg
130.222 µg/kg
Lemmens inlet
Not sampled
982.147 µg/kg
982.147 µg/kg
Grice Bay
Not sampled
573.303 µg/kg
573.303 µg/kg
Dixon Island
13.689 µg/kg
13.689 µg/kg
547.718 µg/kg
547.718 µg/kg
Saturna Island
60.968 µg/kg
60.968 µg/kg
480.478 µg/kg
480.478 µg/kg
Fulford Harbour 1
13.234 µg/kg
13.234 µg/kg
540.576 µg/kg
540.576 µg/kg
Fulford Harbour 2
463.048 µg/kg
463.048 µg/kg
205.222 µg/kg
205.222 µg/kg
Patricia Bay
554.302 µg/kg
554.302 µg/kg
917.525 µg/kg
917.525 µg/kg
Finnerty Cove 1
Not analyzed
311.444 µg/kg
311.444 µg/kg
Finnerty Cove 2
Not sampled
26268.4 µg/kg
26268.4 µg/kg
Victoria Harbour 1
Not sampled
47192.9 µg/kg
47192.9 µg/kg
Victoria Harbour 2
602.398 µg/kg
602.398 µg/kg
21762.9 µg/kg
21762.9 µg/kg
Victoria Harbour 3
Not sampled
20656.4 µg/kg
20656.4 µg/kg
Victoria Harbour 4
390.818 µg/kg
390.818 µg/kg
932.195 µg/kg
932.195 µg/kg
Albert Head 1
4.16318 µg/kg
4.16318 µg/kg
1692.73 µg/kg
1692.73 µg/kg
Albert Head 2
Not sampled
South

What are they?

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment, occurring both naturally and as a result of human activities. They contain several carbon and hydrogen rings (benzene rings) that are linked together. There are two major types of PAHs:

  1. Pyrogenic PAHs are formed as a result of the incomplete combustion of organic matter (e.g., forest fires, agricultural burning, and vehicular and industrial emissions). Combustion results primarily in the formation of parent (non-alkylated) PAHs;
  2. Petrogenic PAHs are found in fossil fuels (e.g., oil, gasoline) and include a wide range of alkylated compounds (PAHs with an additional carbon-containing group or groups attached) that are more persistent than their parent.

Some PAHs are also used to make dyes, plastics, and pesticides.

PAH ‘fingerprinting’ can be used to distinguish different sources of PAHs by comparing the PAH composition of environmental samples to the profiles of known source mixtures.

How do they get into the ocean?

Both natural and anthropogenic sources contribute to the thousands of different PAH compounds found in the environment. In the marine environment, natural PAH sources include crude oil seeps and coal and shale deposits, while anthropogenic sources include oil spills and chronic oil discharges from vessels.  Terrestrial sources, including forest fires and agricultural burning, industrial activities, and vehicle use, can also introduce PAHs to the oceans via atmospheric circulation, urban run-off, and discharge from wastewater treatment facilities.1

On a global scale, major contributors to environmental PAH levels include the burning of biofuels (including coal), biomass burning (agricultural waste, deforestation, and wildfires), and vehicle emissions.2,3

Are they a problem?

PAHs derived from human activities are considered persistent organic pollutants (POPs) 4 and can accumulate in food webs. Depending on their size, individual PAHs vary significantly in toxicity and the way they behave in the environment.

The smallest PAH compounds (less than three benzene rings) can break down quickly in the environment via volatilization, dissolution, and microbial degradation. However, their relatively small size also makes them more soluble in water, where they can reach concentrations that make them acutely toxic to fish and other aquatic organisms.5

Mid-sized PAHs (with three to five benzene rings) are less water soluble and can stick to solid particles and accumulate in the tissues of aquatic organisms. In fish, these compounds can cause cardiac dysfunction, deformities, reduced growth, and increased mortality.6 They can also affect the reproductive and immune systems 7,8,9, and some are known to cause cancer. 10 Larger PAHs (five or more benzene rings) do not break down quickly and are most commonly found in sediment, where they can persist for years. Some large PAHs are known to cause cancer and affect DNA.11

FACT: In the hours and days following an oil spill, smaller, lighter PAHs are lost to evaporation and dissolution, while larger, heavier PAHs can sink and remain in the environment for months to years.

While many organisms can break down parent PAHs, alkylated PAHs may be more difficult to break down and therefore may accumulate in food webs.12 In many cases, alkylated PAHs have also been shown to be more toxic than parent (non-alkylated) PAHs.10,13,14

The United States Environmental Protection Agency has identified 16 priority parent PAHs that are thought to cause cancer as well as effects on the immune, reproductive, nervous and endocrine systems. The most toxic parent PAH is benzo(a)pyrene (five benzene rings).

What is being done?

Sediment quality guidelines protective of marine aquatic life are available for several PAHs. However, these guidelines are not protective of marine organisms higher in the food chain (e.g., marine mammals, birds).

What can we do?

As individual and organizations we can:

  • Learn more about PAHs using the resource links below
  • Recycle and dispose of waste according to local regulations

More information?

1 Latimer, JS, Zheng, J. 2003. The sources, transport, and fate of PAHs in the marine environment. In Douben, PET, ed., PAHs: An Ecotoxicological Perspective, John Wiley & Sons, p. 9-34.

2 Shen G, Chen Y, Liu J. 2013. Global atmospheric emissions of polycyclic aromatic hydrocarbons from 1960 to 2008 and future predictions. Environmental Science and Technology 47: 6415-6424.

3 Ramesh A, Archibong AE, Hood DB, Guo Z, Loganathan BG. 2011. Global environmental distribution and human health effects of polycyclic aromatic hydrocarbons. In Lam, PKS, ed., Global Contamination Trends of Persistent Organic Chemicals, CRC Press, p. 97-126.

4 Burgess, RM, Ahrens MJ, Hickey CW. 2003. Geochemistry of PAHs in aquatic environments: source, persistence, and distribution. In Douben, PET, ed., PAHs: An Ecotoxicological Perspective, John Wiley & Sons, p. 35-45.

5 Greer CD, Hodson PV, Li Z, King T, Lee K. 2012. Toxicity of crude oil chemically dispersed in a wave tank to embryos of Atlantic herring (Clupea harengus). Environmental Toxicology and Chemistry 31(6): 1324-1333.

6 Heintz RA, Rice SD, Wertheimer AC, Bradshaw RF, Thrower FP, Joyce JE, Short JW. 2000. Delayed effects on growth and marine survival of pink salmon Oncorhynchus gorbuscha after exposure to crude oil during embryonic development. Marine Ecology Progress Series 208:205-216.

7 Hall AT, Oris JT. 1991. Anthracene reduces reproductive potential and is maternally transferred during long-term exposure in fathead minnows. Aquatic Toxicology 19:249–264.

8 Reynaud S, Deschaux P. 2006. The effects of polycyclic aromatic hydrocarbons on the immune system of fish: A review. Aquatic Toxicology 77: 229-238.

9 Kennedy CJ, Farrell AP. 2008. Immunological alternations in juvenile Pacific herring, Clupea pallasi, exposed to aqueous hydrocarbons derived from crude oil. Environmental Pollution 153:638-648.

10 CCME (Canadian Council of Ministers of the Environment), 2008. Canadian Soil Quality Guidelines for Carcinogenic and Other Polycyclic Aromatic Hydrocarbons (Environmental and Human Health Effects). Scientific Supporting Document. 218 pp.

11 Tuvikene A. 1995. Responses of fish to polycyclic aromatic hydrocarbons (PAHs). Annales Zoologici Fennici 32:295-309.

12 Harris KA, Nichol LM, Ross PS. Hydrocarbon concentrations and patterns in free-ranging sea otters (Enhydra lutris) from British Columbia, Canada. Environmental Toxicology and Chemistry 30: 2184-2193.

13 Hodson PV, Khan CW, Saravanabhavan G, Clarke LMJ, Brown RS. 2007a. Alkyl PAH in crude oil cause chronic toxicity to early life stages of fish. In Proceedings of the 30th Arctic and Marine Oil Spill Program (AMOP) Technical Seminar. Edmonton, Alberta: Emergencies Science and Technology Division, Environment Canada.

14 Le Bihanic F, Morin B, Cousin X, Le Menach K, Budzinski H, Cachot J. 2014. Developmental toxicity of PAH mixtures in fish early life stages. Part I: adverse effects in rainbow trout. Environmental Science and Pollution Research 21: 13720-13731.

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