Bacteria on the Beach – a growing concern
“MYSTERY ON OUR BEACHES” is the lead front page story in today’s SUN SENTINEL newspaper (Fort Lauderdale) describing a significant rise in bacteria levels on public beaches with concern for public health. The article can be read at http://articles.sun-sentinel.com/2010-09-18/health/fl-beach-closures-20100917_1_bacteria-levels-high-bacteria-enterococcus
While this article focuses on a local problem, it should be seen in a larger context. Bacteria on the beach and in the ocean is becoming a fairly widespread issue that will be with us for a very long time. It is worth looking at one particular category, MRSA, that has often been in the news over the past few years, as it presents a serious health risk .
Generally our image of seawater is being cleansing and extremely healthful. Aside from being recreational and relaxing, it has been used for many therapeutic tasks from skin conditions to drying out one’s sinuses. Seawater generally was not associated with bacterial problems, except for rare cases of sewage outfalls or similar sources. Even then the power of the ocean to dilute to infinitesimal levels,and the enormous range of microbes, animal, and plant life typically eliminated the harmful bacteria. That was the ocean of our grandparents, and for many of us, our youth. It still exists in many places, most of the time. But a sea change has also been taking place, generally unnoticed.
Bacteria need the right environment to multiply, which means nutrients — like most living organisms. They are temperature sensitive; warmer is better. Concentration is a big factor in growth rate. Over time, when exposed to antibiotics, resistant strains develop.
The cause of the increased bacteria levels can be associated with the following:
- Higher population levels and density, particularly on the coasts – a global trend over many decades.
- Many areas do not have adequate municipal sewage treatment, both in the developing world and in the advanced world (Surprisingly for example, San Diego does not treat sewage before dumping it far out in the ocean.)
- Many less populated areas still rely on septic tanks, or even direct dumping of untreated sewage. In lower concentrations, the ocean was better able to deal with the microbial levels.
- Runoff from land and rivers from agricultural regions bring more fertilizer rich material into the sea.
- Some of our effluent now contains antibiotic resistant bacteria strains. Pronounced examples have occurred when some of the waste ponds from intensive pig and chicken farms have ruptured and made their way to rivers, and eventually marine environments.
- In many cases wastewater includes advanced medicines and biologic materials that typical community treatment plants may not neutralize.
- Warmer ocean temperatures. Over the last century global ocean temperatures rose by approximately one degree C (two degrees F) on average. While gradual, as a recent blog post pointed out, temperature sensitivity for corals and other critters — including humans — is much greater than we would imagine. The trend of warming ocean will continue with the overall increasing air temperature due to the greenhouse gas effect, although somewhat delayed.
Of particular concern is the rise in MRSA viruses in coastal waters and on public beaches. MRSA is the highly resistant bacteria that even presents a big challenge to hospitals, both in terms of treatment and prevention. (A good blurb on MRSA can be found on Wikipedia at http://en.wikipedia.org/wiki/Mrsa)
My conclusions:
- The ocean and the beach is still a great place for recreation.
- Particularly in areas with suspect sewage sources nearby, including any huge populations, be careful not to go in the water with open wounds.
- If you do see signs of something suspicious such as an infection, see a medical expert.
- This problem will continue to worsen due to higher population levels and concentrations, and with the gradual warming, otherwise known as climate change.
- It’s not our grandparents’ ocean.