A Monitor's Guide to Water Quality

Hydrocarbons with applicable Canadian Council of Ministers of the Environment (CCME) environmental guidelines.

Hydrocarbon Groups Constituents with CCME Guidelines (Water and Sediment)


Benzene, Toluene, Ethylbenzene, Xylenes (soil only)

Polycyclic Aromatic Hydrocarbons (PAHs) or Poly­cyclic Aromatic Compounds (PACs)

2-Methylnapthalene (sediment only), Acenaphthene, Acenaphthylene (sediment only), Acridine (water only), Anthracene, Benz(a)anthracene, Benzo(a) pyrene, Chrysene (sediment only), Dibenz(a,h) anthracene (sediment only), Fluoranthene, Fluorene, Naphthalene, Phenanthrene, Pyrene, Quinoline (water only)

Hydrocarbons behave differently in the environment depending on their structure.

BTEX hydrocarbons dissolve easily in water. However, they are not very persistent over time in part because they evaporate so easily. Despite this, BTEX substances can persist in aquatic ecosystems for days or weeks, and can have negative impacts on the organisms that live in the water.

PAHs are more persistent in aquatic ecosystems, and accumulate in sediments and in some organisms. PAHs can easily attach to particles in the air, so they can be transported through the air and deposited in locations far away from their source.

Why do they matter?

Hydrocarbons can be harmful to aquatic ecosystems and to humans. BTEX hydrocarbons can be toxic to aquatic life if present in sufficiently high concentrations. Benzene is carcinogenic (cancer causing) in humans, and toluene is toxic to the nervous system.

Several PAHs are considered probable or possible human carcinogens and have been found to cause certain cancers, mutations and birth defects in fish and other animals.

How are they measured?

In aquatic ecosystems, BTEX and PAHs can be measured in water or sediments. Some can also be measured in the tissues of organisms like fish. Hydrocarbon samples must be submitted to a lab for analysis.

BTEX hydrocarbon results are usually reported individually as benzene, toluene, ethylbenzene and xylenes. There are many different PAH compounds and they can be reported individually, or grouped together according to their “parent” PAH compound (e.g., napthalene).