Unanswered Questions in Miami

The EPA didn't reveal new beach water quality monitoring criteria at its just concluded annual National Beach Conference. But there were other tidbits to share.

I spent last week at the EPA’s National Beach Conference in Miami, where I gave a couple of presentations, learned about the latest in beach water quality research, and heard from EPA on the upcoming criteria for measuring water quality.

EPA’s criteria haven’t been updated since 1986, and the new rules are required to be completed by the end of 2012 under a Consent Decree with the NRDC.  With the recent completion of a comprehensive research plan, EPA staff members have all the information they’ll use to develop the new criteria.

Unfortunately, within the first two hours of the conference it became clear that the EPA wasn’t far enough in criteria development to share anything new with conference participants.  Instead, we were told that the draft criteria will make their debut June 14-15 at a meeting in New Orleans.

Conference participants asked if the new criteria would be as protective as the existing ones. (Current criteria are based on an 8 in a 1,000 risk of stomach flu for swimmers at freshwater beaches and 19 in 1,000 for ocean beaches).  Also, they asked if the criteria would allow states, cities or counties to develop site-specific rules.  And would beach monitoring programs be required to use rapid methods to quantify fecal bacteria densities in a few hours rather than waiting until the next day?

All questions were left unanswered.

Despite the lack of clarity on the direction of the criteria, there were some noteworthy outcomes at the conference.

Watchdogs in the Great Lakes area have really moved forward in their efforts to develop predictive models for many of their beaches.  The models, often developed by the U.S. Geological Survey, predict beach water quality based on rainfall, swell direction and swell height, water temperature, flow from nearby rivers and drains, and other factors.

Imagine picking up the paper every morning to read what the predicted water quality is at Malibu, Will Rogers or El Porto.  That’s what they’re doing at numerous Great Lakes beaches.

The predictions are right between 65% and 85% of the time depending on the beach, so that’s better than a coin flip.  In general, the models are more accurate than the previous day’s water quality by a margin of about 10%-15%.

California hasn’t moved forward with an ocean beach predictive model, although Stanford University and Heal the Bay have been looking for funding for a California model for over three years.

The panel on epidemiology studies was noteworthy because most of the health effects studies actually didn’t tell us much. The EPA studies on an urban runoff impacted beach in South Carolina and a heavily visited tropical beach in Puerto Rico didn’t reveal a lot because the water quality was so good at those beaches.

As a result, the study didn’t demonstrate a relationship between fecal bacteria levels and adverse health effects — hardly surprising with such excellent water quality.

The urban runoff water quality in the stormdrains discharging to Surfside Beach in South Carolina was cleaner than some of our Santa Monica Bay beaches — and that’s without any ocean dilution!

The health effects study at Hobie Beach in Miami (performed by U of Miami scientists) also didn’t have a strong association between fecal indicator bacteria densities and stomach flu – a similar outcome to the Mission Bay health effects study that UC Berkeley and the Southern California Coastal Waters Research Project (SCCWRP) performed a few years ago.

These studies were both located at beaches with high fecal bacteria counts, but no visible source of flowing pollution to the beach (no drains or creeks).  More conventionally, the Berkeley/SCCWRP study on Orange County’s Doheny Beach demonstrated an association between fecal bacteria densities and stomach flu when the lagoon berm was breached and the creek water flowed to the beach. This association fell apart when the berm was in place.

The conference covered a lot of other areas, ranging from the latest breakthroughs in the use of rapid methods for quantifying fecal bacteria densities to source tracking methods to identify pollution sources.

The rapid methods application studies were interesting.  Although there has been incredible progress in the field, there are still questions about the rapid methods’ variability, e.g. how much does the bacteria amount vary from split sample to sample and lab to lab?

There are also questions about effectiveness when there is interference from polluted runoff or other substances, and the relationship with adverse health effects in marine waters.  As a result, look for EPA to come up with a recommended standard rapid method for enterococcus and e.coli bacteria, but don’t look for them to require use of the method anytime soon.

A few scientists presented on the use of Quantitative Microbial Risk Assessment to determine the risk of swimming at beaches with runoff pollution sources.  These scientists were confident that the principle cause of stomach flu in swimmers is norovirus.  The problem is that environmental assays for norovirus aren’t quite ready for widespread use.

Also, the QMRA techniques are estimates of actual risk that don’t take into account water quality variability over time.  For example, swimming at a beach today after a four-inch rain is a lot riskier than swimming at a beach in August when most stormdrains and creeks are running dry.  Still, the approach shows some promise in less developed areas like beaches downstream of agricultural communities.

All in all, the conference offered promise because there has been so much new research over the last couple of years.  There are so many scientists working on beach water quality issues today.  A few years ago, the numbers were a lot smaller.

As a result, we are on the verge of some exciting findings and new opportunities for more effective public health risk management.  My big concern is that the findings of many of these studies will be used to discount the risk to public health.




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