Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Beach pollution is worst during new and full moon

02.08.2005


A new study of 60 beaches in Southern California suggests that water pollution varies with the lunar cycle, reaching the highest levels when tides are ebbing during the new and full moon. The findings could help beachgoers and managers better assess the potential risk of swimming.



The report appears in the Aug. 1 issue of the American Chemical Society’s journal Environmental Science & Technology. ACS is the world’s largest scientific society.

Coastal water quality is controlled by a number of complex physical and biological factors, including tidal cycles and seasonal rainfall. This complexity makes beach water monitoring difficult, with levels of bacteria in a certain area changing in just a few minutes.


For the new study, the researchers examined monitoring data compiled for beaches throughout Southern California, keeping track of tidal patterns and analyzing them for concentrations of enterococci -- bacteria that allow scientists to estimate the risk of illness from swimming in marine waters. "This is the largest array of beaches examined at the same time for a similar pattern," says Alexandria Boehm, Ph.D., an environmental engineer at Stanford University and lead author of the study.

She and her colleagues at the Southern California Coastal Water Research Project found that in the full and new phases of the moon, levels of enterococci were higher at the vast majority of the beaches studied. Boehm found that during so-called "spring tides," when water levels vary the most between high and low tides, a beach is twice as likely to be out of compliance with water quality standards. Spring tides are exceptionally high or low tides that take place during the full and new moons, but have nothing to do with the season of the year.

The results are of immediate practical use to swimmers and beach managers alike, according to Boehm. "The general public can use the phase of the moon and the tide stage to assess the relative risk of illness," she says. "It is riskier to swim during spring-ebb tides [receding tide] compared to all other tidal conditions."

Beach managers can now use tides as they currently use rainfall to assess warnings, Boehm suggests. When it rains, managers recommend that swimmers not enter the water for three days. "They could also suggest that during spring tides -- and especially spring-ebb tides -- water quality is more likely to be impaired, and those who are risk-averse should avoid swimming," Boehm says.

The results might also help managers identify potential sources of pollution at beaches. "Most sources of enterococci at beaches are unknown," Boehm says. "Because we found tidal signals in enterococci densities at beaches with no obvious point source, like storm drains and creeks, this suggests that there is a widespread tidally forced source of enterococci at beaches."

Boehm suggests several candidates for this "mystery" source, including beach sands, decaying plant material and polluted groundwater. "Beach sands and wrack [piles of seaweed and animal remains that wash ashore] have been shown at freshwater beaches to harbor fecal indicator bacteria and even pathogenic bacteria," Boehm says. "Beach managers who want to improve water quality at their beaches should investigate the potential of these sources to be contributors of enterococci to marine waters."

Boehm cautions that enterococci from beach sands and wrack may not correlate with health risk the same way as enterococci from runoff or sewage. "We just don’t know for sure, since no one has done an epidemiological study to connect human illness to enterococci from non-point sources other than runoff," Boehm says. "We need to do additional work to understand the source of enterococci at all these beaches."

Michael Bernstein | EurekAlert!
Further information:
http://www.acs.org

More articles from Studies and Analyses:

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

 
Latest News

Information integration and artificial intelligence for better diagnosis and therapy decisions

24.05.2017 | Information Technology

CRTD receives 1.56 Mill. Euro BMBF-funding for retinal disease research

24.05.2017 | Awards Funding

Devils Hole: Ancient Traces of Climate History

24.05.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>