Official study confirms fears that car washing chemicals have detrimental impact on fish

It may seem as harmless of a summer activity as gardening and barbeques, but car washing in Federal Way appears to have a significant and negative impact on local fish populations, a recent study reports.

Adding car washing residue of chemicals, soap and grime to Federal Way stream plays a detrimental role to spawning salmon, native trout and other aquatic life in our creeks and rivers.

A recent toxicity study conducted by a local consulting group, Environmental Partners, Inc. confirms the lethal effects of car wash run-off on fish.

According to the study, car wash effluent from a sample car wash resulted in high rates of fish mortality in a series of tests that were analyzed using an approved Environmental Protection Agency method for measuring toxicity of effluents to freshwater and marine organisms.

In the first set of tests, juvenile rainbow trout were placed in diluted samples of car wash run-off, which contained soap, water, car grime and parking lot grime.

At the end of the 24-hour test there was 100 percent mortality in every batch. Even the most diluted batch, with only 6.5 percent effluent, was lethal to all of the trout.

The second set of tests was run on the detergent mixed with water.

No car or parking lot grime was included in this test. The detergent was mixed with water per the manufacturer recommendations.

The sample was then diluted to simulate car washing rinse water. Juvenile rainbow trout were then placed in each batch in an attempt to find the lethal concentration of the detergent.

The final test results indicated that even at less than two parts per million concentration, the detergent was lethal to 50 percent of the juvenile rainbow trout.

"The findings of this study clearly indicate the reality of just how toxic car wash detergent and effluent can be to aquatic life," said Don Robinett of Federal Way's Water Quality Team.

"Consider what the potential toxic effects to a single fish bearing stream would be from the cumulative impacts of numerous car washes that can occur in a watershed on a typical summer weekend," he said.

"This report gives us a strong reminder of the importance of washing our cars on our lawns, or at a licensed car wash, where the wash water receives treatment. Further, when planning a car wash fundraiser, be sure to reserve a car wash kit so the water is discharged to the sanitary sewer system," said Robinett.