On May 23, the Heal the Bay organization released their 17th annual “Beach Report Card,” summarizing the results of water-quality monitoring on California’s beaches (http://www.healthebay.org/assets/pdfdocs/brc/annual/2007/report_web.pdf) . The majority received good marks, but the organization noted a few areas for improvement. That will require understanding the limitations of the report's data, and any measures taken to address the problems need to consider the quality of the original data.

Heal the Bay gave 79 percent of the monitored beaches an “A” for water quality during April through October. During the wetter winter months of November through March, water quality data are more difficult to interpret consistently because of spikes and flashes due to heavy runoff events.  In Los Angeles County, only 56 percent of the beaches received an A or B, and seven of the 10 lowest quality beaches were in this county.

Does this mean that LA County has the worst beach water quality in the state?  Certainly there are some reasons for concern, but it turns out that one part of the difference in LA County is the monitoring itself.  In this area, water quality samples were collected directly from the output of storm drains, as opposed to well-mixed areas.  This sampling strategy was dictated by local circumstances, and was not consistent with the way samples were collected at most other beaches.

The group points out that children play directly in front of storm drains, or sometimes even in detention ponds and lagoons for holding runoff.  So determining the quality of these locations may provide valuable information for those situations. As Heal the Bay points out, “point zero” is the most conservative place to measure for human health indicators.  On the other hand, it does not truly represent bay or beach water quality in a comprehensive sense, but rather storm-drain water quality. 

This study defines water quality on the basis of measured levels of indicator bacteria, coliform and enterococcus.  Neither of these bacteria are harmful in and of themselves, but are good indicators that other water-quality impairments that pose a risk to human health may be present.  Thus, high indicator bacteria levels are a red flag, but not dangerous themselves.  The report notes this, stating that these indicators are a measure of potential risk, not of toxins or dangerous compounds.  They also note that “beachgoers should determine what they are comfortable with in terms of relative risk, and then make the necessary decisions to protect their health.”

The valuable work done by the local agencies and dischargers who provide the data, and the Heal the Bay organization in analyzing and summarizing the data is underscored by the need for systematic, consistent monitoring. Monitoring projects are critical to understanding the state of our nation’s resources, targeting improvement efforts at the most impaired areas, and documenting success or failure of those efforts.

When results are disseminated, caveats and shortcomings of the data must be revealed as well. Heal the Bay did so, but some subsequent reports on their findings did not. Those in a position to take action must proceed with a full understanding of what the results really are.