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 Drone vs. truck deliveries: Which create less carbon pollution?
31.05.2017 | University of Washington

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)

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: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Extensive Funding for Research on Chromatin, Adrenal Gland, and Cancer Therapy

28.06.2017 | Awards Funding

Predicting eruptions using satellites and math

28.06.2017 | Earth Sciences

Extremely fine measurements of motion in orbiting supermassive black holes

28.06.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>