Environment and Sustainable Resource Development (ESRD) has received the water chemistry analysis from the Suncor spill on March 25, 2013.
We have reviewed the results of the undiluted process-water samples and compared them to the Alberta Surface Water Guidelines. The results are summarized below.
The process-affected water that was released did not meet all parameters of these guidelines, and did not pass the standard 96-hour rainbow trout acute toxicity test; however, there is no concern to human health.
Analysis indicates that the most likely cause for the acute toxicity observed in the rainbow trout toxicity test is the naphthenic acid concentration (24 mg/L).
Naphthenic acids are a group of compounds with variable toxicity that occur naturally in bitumen, and are present at low levels in creeks that cut through bitumen deposits. In bitumen-process-affected waters, these water-soluble compounds are often concentrated.
We are currently reviewing the effects of dilution of the process-affected water by both treated water in the combined outfall pipe and the river water. This will help determine what potential environmental impacts may have occurred.
Full laboratory results will not be released at this time, as they are considered evidence in the ongoing investigation into the incident. The investigation process is ongoing and will determine what type of enforcement action may be necessary.
- Trace levels of hydrocarbon fractions were found to be near detection levels for F1 and F2, which are the predominant fractions for gasoline and diesel, respectively;
- Traces of xylenes were found to be well below the aquatic life guideline;
- No benzene, toluene or ethylbenzene was detected.
- Trace levels of three PAHs (polycyclic aromatic hydrocarbons) were detected, but not at concentrations that would be expected to cause harm to the river.
- Two of the three (naphthalene and chrysene) were well below guidelines.
- The third (pyrene) was present at twice the chronic guideline for aquatic life, but not at levels that would pose a risk to aquatic life.
- Chloride concentration was 630 mg/L – which is above chronic guideline of 130 mg/L, but below short-term guideline of 640 mg/L.
- Other salt ions, primarily sodium and bicarbonate, were also present at elevated concentrations, and contributed to a Total Dissolved Solids concentration of 2100 mg/L. While not acutely toxic at these concentrations, unauthorized releases of salts into the river are not desirable.
- Nitrate/nitrite concentrations were below guidelines.
- Phosphorus was within the normal range for the river.
- Ammonia concentration was 3.2 mg/L and is above the chronic aquatic life guideline for the river pH and temperature, but is not expected to cause chronic toxicity over the short term of this release.
Trace elements were below guidelines except for:
- Arsenic: 0.011 mg/L (chronic aquatic life guideline is 0.005 mg/L);
- Boron: 3.2 mg/L (chronic aquatic life guideline is 1.5 mg/L);
- Selenium: 0.0050 mg/L (chronic aquatic life guideline is 0.001 mg/L);
- Cadmium: 0.18 micrograms/L, (chronic guideline for aquatic life in 150 mg/L hardness water is 0.047 mg/L); and
- Zinc: 0.061 mg/L (chronic aquatic life guideline of 0.03 mg/L).
Trace element exceedances are not expected to cause harm to aquatic life over the short duration of the release.
For more information on our Compliance Assurance Program, please visit our website.