Polycyclic aromatic hydrocarbons in freshwater and marine water

​​Toxicant default guideline values for protecting aquatic ecosystems

October 2000

Description of chemical

Polycyclic aromatic hydrocarbons (PAHs) are formed by incomplete combustion of organic material, diagenesis and biosynthesis. Natural sources include forest fires, volcanic activity, diagnosis and, possibly, production by some plants and microorganisms; however, a significant fraction of PAHs result from anthropogenic combustion processes (CCREM 1987). Atmospheric deposition is believed to be a significant route of entry into the aquatic environment, but materials containing PAHs may also directly enter the water system via release of crude oil and petroleum products (CCREM 1987). PAHs are commonly found in road runoff. Naphthalene, the simplest PAH, is used as an insect-proofing agent for stored material and clothing. The log K_ow of naphthalene is 3.4 but most other PAHs have log K_ow values between 4 and 6. Sixteen PAHs have been identified as Priority Pollutants by the World Health Organization (WHO), the former European Economic Community (EEC) and the US Environmental Protection Agency (EPA) (Hellou 1996). The current analytical practical quantitation limit (PQL) for naphthalene is 0.1 µg/L (NSW EPA 2000).

Concentrations of PAHs in aquatic ecosystems are generally highest in sediments, intermediate in aquatic biota and lowest in the water column (Neff 1979, NRCC 1983). In field studies, sorption to suspended particles and bed sediments was found to be the primary removal mechanism for high-molecular weight PAHs, whereas volatilisation and transport were the primary mechanisms for low-molecular weight PAHs (ANZECC 1992). Mixed microbial population in sediment water systems may degrade some PAHs, with degradation progressively decreasing with increasing molecular weight (CCREM 1987).

Aquatic toxicology

The US EPA prepared documents on ambient water quality guidelines for naphthalene (1980g), fluoranthene (1980h), phenanthrene (1988c) and polynuclear aromatic hydrocarbons (1980r); however, except for phenanthrene, insufficient data were available to recommend numerical limits. The acute toxicities of fluoranthene and naphthalene to freshwater aquatic life were around 4000 µg/L and 2300 µg/L respectively (USEPA 1980h, 1980g). Acute toxicity to saltwater aquatic life occurs at concentrations as low as 40 µg/L for fluoranthene. USEPA (1988c) developed guidelines (4-day average) for phenanthrene in fresh and salt water, resulting in concentrations of 6.3 µg/L and 4.6 µg/L respectively. Benzo(a)pyrene is highly lipophilic, and bioconcentration factors ranged from 930 in the mosquito fish to 134,240 in Daphnia pulex (CCREM 1987). Mixtures of polycyclic aromatic hydrocarbons have been found to cause tumours in fish (IJC 1983, Hawkins et al. 1990). PAHs are commonly associated with sediments and sediment contamination is a source of uptake in tissues (Hellou 1996).

Jarvinen and Ankley (1999) report data on tissue residues and effects for anthracene, fluorene, phenanthrene, pyrene and benzo(a)pyrene for three freshwater species and two marine species. It is not possible to summarise the data here but readers are referred to that publication for more information.

Data were available for the following PAHs but there were only sufficient data for naphthalenes to calculate a reliable guideline value. Toxicity data are given below.

Naphthalene (CAS 91-20-3) (2-ring PAH)

Freshwater fish: four species, 96-hour LC50, 120 to 7900 µg/L. Chronic NOEC Pimephales promelas, 30-day growth and hatching, 450 µg/L and mortality, 1800 µg/L; Sarotherodon mossambicus, 84-day growth, 2300 µg/L. The figure of 120 mg/L for Oncorhynchus mykiss was an order of magnitude lower than the next lowest for the same species. The geometric mean for the species was 2220 mg/L.

Freshwater crustaceans: four species, 48 to 96-hour LC50, 2160 to 57,520 µg/L. Figures for Diaptomus forbesi (67,800 µg/L) were more than twice the water solubility.

Freshwater insects: three species, 48-hour LC50, 27 µg/L (Aedes aegypti) to 20,700 µg/L. The mosquito figure appears to be anomalous and may need to be checked.

Freshwater mollusc: Physa gyrina, 48-hour LC50, 5000 µg/L.

Freshwater algae: Chlorella vulgaris, 48-hour EC50 growth, 33 000 µg/L.

Marine fish: four species, 48 to 96-hour LC50, 750 to 5300 µg/L. Chronic NOEC (two species, 35-day growth) of 120 to 560 µg/L.

Marine crustaceans: six species, 48 to 96-hour LC50, 850 to 5700 µg/L. Chronic NOEC, Cancer magister, 63-day development 21 µg/L.

Marine mollusc: one species, Katelysia opima, 96-hour LC50, 57,000 µg/L.

Marine annelids: one species, Neanthes arenaceodentata, 96-hour LC50, 3800 µg/L.

Anthracene (CAS 120-12-7) (3-ring PAH)

Freshwater fish: two species, 96-hour LC50, 1.3 to 46 µg/L.

Freshwater crustaceans: two species, 48 to 96-hour LC50, 36 to 3030 µg/L. Chronic NOEC D. magna, 0.6 to 4.1 µg/L.

Freshwater insect: Aedes aegypti, 48-hour LC50, 27 µg/L.

Freshwater algae: 6-day NOEC (growth and mortality) 1.5 to 7.8 µg/L.

Phenanthrene (CAS 85-01-8) (3-ring PAH)

Freshwater fish: one species, O. mykiss, 96-hour LC50 of 3200 µg/L (above water solubility); chronic NOEC for Brachydanio rerio (21-day growth), 32 to 56 µg/L.

Freshwater crustaceans: three species, 48 to 96-hour LC50, 100 to 1158 µg/L. Chronic NOEC figures for D. magna (21-day growth, mortality, reproduction) of 18 to 180 µg/L; D. pulex (49-day growth, reproduction) of 60 to 110 µg/L.

Freshwater insects: Chironomus tentans, 48-hour LC50, 490 µg/L.

Marine crustacean: Mud crab Rhithropanopeus harrisii, 7-day NOEC (mortality) of 150 µg/L.

Marine annelid: Neanthes arenaceodentata, 96-hour LC50, 51 to 600 µg/L.

Fluoranthene (CAS 206-44-0) (4-ring PAH)

Freshwater fish: Ictalurus punctatus, 96-hour LC50, 36 µg/L. A figure of 4000 µg/L for Lepomis macrochirus was well above water solubility. Chronic NOEC figures for Brachydanio rerio (41-day growth, mortality) of 6.9 to 69 µg/L (geometric mean of 12.3 µg/L).

Freshwater crustaceans: two species, 48 to 96-hour LC50, 45 to 92 µg/L; chronic NOEC for two species (10-d, mortality) of 18 to 180 µg/L.

Freshwater insect: Chironomus tentans, 10-day NOEC of 30 µg/L.

Marine annelid: Neanthes arenaceodentata, 96-hour LC50, 300 µg/L.

Benzo(a)pyrene (CAS 50-32-8) (5-ring PAH)

Freshwater fish: B. rerio, 42-day NOEC (mortality) of 6.3 µg/L.

Freshwater crustacean: D. pulex, 96-hour LC50, 5 µg/L.

Freshwater algae: two species, 72-hour EC50 (growth), 5 to 15 µg/L.

Factors that affect toxicity

PAHs will adsorb strongly to sediment, suspended matter and organic matter. UV light is one of the major factors that increases the toxicity of PAHs. Photoactivation of toxicity of PAHs up to one order of magnitude has been reported.

Guidelines

Naphthalene

Anthracene

Phenanthrene

Fluoranthene

It was not possible to derive a high or moderate reliability trigger value, so the chronic data were supplemented with QSAR data.

Benzo(a)pyrene

It was not possible to derive a high or moderate reliability trigger value, so the chronic data were supplemented with QSAR data.

References

ANZECC 1992. Water quality guidelines for fresh and marine waters. Australian and New Zealand Environment and Conservation Council, Australian Government Publishing Service, Canberra.

ANZECC & ARMCANZ 2000. Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand, Canberra.

CCREM 1987. Canadian water quality guidelines. Canadian Council of Resource and Environment Ministers, Ontario.

NSW EPA 2000. Analytical Chemistry Section, Table of Trigger Values 20 March 2000, LD33/11, Lidcombe, NSW.

Hawkins WE, Walker WW, Overstreet RM, Lytle JC & Lytle TF 1990. Carcinogenic effects of some polychlorinated aromatic hydrocarbons on the Japanese medaka and guppy in waterborne exposures. Science of the Total Environment 94, 155–167.

Hellou J 1996. Polycyclic aromatic hydrocarbons in marine mammals, finfish and molluscs. Chapter 9 in Environmental contaminants in wildlife: Interpreting tissue concentrations,eds WN Beyer , GH Heinz & AW Redmon-Norwood. SETAC Special Publication Series. CRC Press, Lewis Publishers, Boca Raton.

IJC 1983. Annual report on the aquatic ecosystem objectives committee. Great Lakes Science Advisory Board, International Joint Commission, Windsor, Ontario.

Jarvinen A W & Ankley G T 1999. Linkage of effects to tissue residues: Development of a comprehensive database for aquatic organisms exposed to inorganic and organic chemicals. SETAC Technical Publication Series, SETAC Press, Pensacola FL.

Neff JM 1979. Polycyclic aromatic hydrocarbons in the aquatic environment. Sources, fate and biological effects. Applied Science Publishers, London.

USEPA 1980g. Ambient water quality criteria for naphthalene. Criteria and Standards Division, US Environmental Protection Agency, Washington DC.

USEPA 1980h. Ambient water quality criteria for fluoranthene. Criteria and Standards Division, US Environmental Protection Agency, Washington DC.

USEPA 1980r. Ambient water quality criteria for polynuclear aromatic hydrocarbons. US Environmental Protection Agency, Washington DC.

USEPA 1988c. Ambient aquatic life criteria for phenanthrene. US Environmental Protection Agency, Environmental Research Laboratories, Duluth, Minneso