 |
|
Beach pollution is worst during new and full moon
August 02, 2005A 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."
American Chemical Society
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."
American Chemical Society
Water Quality Current Events and Water Quality News RSSNutrients in water may be a bonus for agriculture
Agriculture producers may find they don't have to bottle their water from the Seymour Aquifer in the Rolling Plains to make it more valuable, according to Texas AgriLife Research scientists.
Urban Trees Enhance Water Infiltration
Global land use patterns and increasing pressures on water resources demand creative urban stormwater management.
Shifts in soil bacterial populations linked to wetland restoration success
A new study led by Duke University researchers finds that restoring degraded wetlands -- especially those that had been converted into farm fields -- actually decreases their soil bacterial diversity.
'Arid aquaculture' among livelihoods promoted to relieve worsening pressure on world's drylands
"Arid aquaculture" using ponds filled with salty, undrinkable water for fish production is one of several options experts have proven to be an effective potential alternative livelihood for people living in desertified parts of the world's expanding drylands.
Fertilizers - a growing threat to sea life
New study on landscape around Chesapeake Bay says imbalance in nitrogen cycle is damaging water quality and fish populations.
Pesticide Concentrations Decreasing
The widespread use of pesticides across the United States has been in practice for decades, with little knowledge of the long-term effects on the nation's groundwater.
Brown Scientist Finds Coastal Dead Zones May Benefit Some Species
Coastal dead zones, an increasing concern to ecologists, the fishing industry and the public, may not be as devoid of life after all. A Brown scientist has found that dead zones do indeed support marine life, and that at least one commercially valuable clam actually benefits from oxygen-depleted waters.
Waterborne disease risk upped in Great Lakes
An anticipated increased incidence of climate-related extreme rainfall events in the Great Lakes region may raise the public health risk for the 40 million people who depend on the lakes for their drinking water, according to a new study.
RAND study: Alternative fossil fuels have economic potential
Alternative sources of fossil fuels such as oil sands and coal-to-liquids have significant economic promise, but the environmental consequences must also be considered, according to a RAND Corporation study issued today.
More research needed to make good on biofuel promise, experts say
While cellulosic biofuels derived from grasses, crop residues and inedible plant parts have real potential to be more efficient and environmentally friendly than grain-based biofuels like corn ethanol, more research and science-based policies are needed to reap these benefits, says an international group of experts.
More Water Quality Current Events and Water Quality News Articles
 | Water Quality Control Handbook, Second Edition (Handbook) by E. Roberts Alley Capitalize on the Latest Design and Operating Innovations for Achieving Peak Performance in Any Wastewater Treatment Plant Wastewater treatment professionals can turn to the updated Second Edition of Water Quality Control Handbook for cutting-edge information on designing and operating systems used to treat wastewater from industrial and domestic sources. This state-of-the-art guide... |
| Root Zone Quality Model: Modelling Management Effects on Water Quality & Crop Production & Computer Program by Lajpat Ahuja, K. W. Rojas, J. D. Hanson, M. J. Shaffer, L. Ma | |
 | Surface Water Quality Modeling by Steven C. Chapra Since the 1920's, scientists and engineers around the globe have been using mathematical models to simulate the transport and fate of pollutants in natural waters. Today, and in the foreseeable future, more of these applications are being generated in an effort to develop economical solutions to water-quality problems. The primary audience for this book is first-year graduate students,... |
 | Bakery Food Manufacture and Quality: Water Control and Effects by Stanley P. Cauvain, Linda S. Young Water is the major contributor to the eating and keeping qualities and structure of baked products. Its management and control during preparation, processing, baking, cooling and storage is essential for the optimisation of product quality. This successful and highly practical volume describes in detail the role and control of water in the formation of cake batters, bread, pastry and biscuit... |
 | Land Use Effects on Streamflow and Water Quality in the Northeastern United States by Avril L. de la Cretaz, Paul K. Barten Filling a long-standing need for a desk reference that synthesizes current research, Land Use Effects on Streamflow and Water Quality in the Northeastern United States reviews and discusses the impact of forest management, agriculture, and urbanization. The book provides a gateway to the diverse scientific literature that is urgently needed to understand and solve ubiquitous watershed management... |
 | Water Quality & Treatment Handbook by American Water Works Association State-of-the-art handbook of community water supplies.The leading source of information on water quality, water treatment, and quality control for 60 years is now available in an up-to-the-minute new edition. The American Water Works Association's Water Quality & Treatment, Fifth Edition fully covers the field, bringing you the expertise of 20 distinguished specialists who provide the latest... |
| Water Quality Standards Handbook by U.S. Environmental Protection Agency Covering such topics as designation of uses, antidegradation, procedures for review and revision of water quality standards, and the water-quality-based approach to pollution control, this handbook provides readers with guidance on complying with the Water Quality Standards Regulation, 40 CFR... | |
 | Field Manual for Water Quality Monitoring: An Environmental Education Program for Schools by Mark K. Mitchell, William B. Stapp, Kevin Bixby |
 | Water Quality: Characteristics, Modeling and Modification by George Tchobanoglous, Edward D. Schoeder |
 | Clean Water: An Introduction to Water Quality and Pollution Control by Kenneth M. Vigil "Clean Water" is a book for anyone who is concerned about this precious resource and wants to become better informed. In straightforward language, Kenneth Vigil provides a comprehensive introduction to the many scientific, regulatory, and geographic issues associated with water quality and water pollution control. Most other books on water quality and pollution control are highly technical and... |
| © 2008 BrightSurf.com |