News
Arizona Students Think Outside the Box with Rain Box
Award-winning water generator targets African water scarcity problem
By Debbie Howell
A group of Arizona State University (ASU) students might not have all the answers to solving global water scarcity, but their research efforts potentially could impact a corner of the world close to their hearts – their African homeland.
Six members of the African Students Association at ASU created a prototype device called the Rain Box that converts humidity in the air into clean water, essentially reversing the air-conditioning process using electrical or solar power. The students formed a company called Watel Solutions Corp. to test and eventually market the product, with manufacturing assistance provided by Alter Air Corp., a Tempe, Ariz.-based maker of residential air conditioning units. The units will initially sell for $3,500 to $6,000, with the price expected to eventually drop to about $1,000 as mass production ramps up.
“Just like droplets of water form themselves on the outside of a glass of cold water left in the ambient air, the Rainbox condenses humidity in the air using a vapor compression cooling system. It then filters the condensed water to eliminate dust particles and airborne bacteria using a charcoal filter and ultraviolet light. The final product is tasty and healthy potable water,” said Lionel Metchop, one of the inventors and a mechanical engineering graduate student at ASU.
Other student members of the team are Vahid Dejwakh, Ronald Gahimbare, Usaju Lugogo, Nnditsheni Madavha, and Chris Ndungutse. Watel is partnering with an ASU research group led by Jay Golden and Patrick Phelan, assistant professors at the School of Sustainability and Department of Mechanical and Aerospace Engineering, respectively.
In addition to a grant proposal under review by the Science Foundation of Arizona, Watel is developing a private placement memorandum for future investors.
“The product has a global market that covers the entire region of the world with high humidity. The point of entry of the product in the market will be the port city of Douala, economical capital of Cameroon, which is the major point of import of products distributed in the entire Central Africa market,” Metchop said.
The Rain Box has generated significant attention in the scientific and educational community. In September, Rain Box took first place in the Intel-ASU Technology Entrepreneurship Challenge, winning $10,000 in the competition that honors business plans based on emerging technologies. The next month, the device took third place at the Intel+UC Berkeley Technology Entrepreneurship Challenge, competing against 19 teams from around the world. Watel earned $5,000 in that contest, and another $5,000 as recipient of the People’s Choice Award due to the humanitarian nature of the project.
A prototype was built with the winnings, and now the Rain Box is undergoing tests. Powered by solar energy, the generator can produce about 40 gallons of water a day.
Metchop said the group of students knows firsthand the hardships of growing up in Africa with water scarcity – walking long distances to fetch water or dealing with water-contaminated diseases.
“Existing means of getting water have proven to be insufficient and costly for communities in Africa: well digging, desalination plants, purification plants,” Metchop said. “Watel Solutions Corp. is offering an alternative technology which is environmentally friendly, reliable, portable, and less expensive.”
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Aerosol Pollution
Slows Winds, Reduces Rainfall
Aerosol particles created from vehicle exhaust and other contaminants can accumulate in the atmosphere and reduce wind speeds closer to the Earth’s surface, resulting in less wind power and reduced precipitation, according to the results of a study by Stanford University and the National Aeronautics and Space Administration (NASA).
“These aerosol particles are having an effect worldwide on the wind speeds over land; there’s a slowing down of the wind, feeding back to the rainfall, too,” said Mark Z. Jacobson, a civil and environmental engineering associate professor at Stanford. Jacobson is co-author of the study with the late Yoram J. Kaufman from NASA Goddard Space Flight Center, who died in May 2006. “We’re finding a reduction of rain, and that can lead to droughts and reduction of water supply,” Jacobson said.
The results, announced Jan. 19, were based on analysis of aerosol accumulation data, wind speed measurements over the South Coast Basin in California and in China, and computer model simulations over California related to the effects of aerosol particles on wind speed and rainfall.
Aerosol particles floating in the atmosphere absorb or scatter solar radiation and prevent it from reaching the ground. This cools the Earth’s surface and reduces daytime vertical convection that mixes the slower winds found near the ground with the faster winds at higher altitudes. The overall effect is a reduction in the speed of near-surface winds, which Jacobson has calculated to be up to 8 percent slower in California than wind speeds otherwise would be minus aerosol particles in the air.
Wind power made up 1.5 percent of the state’s energy portfolio in 2005, according to the California Energy Commission. However, slower gusts may reduce wind’s economic competitiveness compared to other energy sources, such as fossil fuels, according to the study.
Aerosol particles may be responsible for the slowing down of winds worldwide. Wind supplies about 1 percent of global electric power, according to Jacobson. Slow winds may hinder development of wind power in China, where it’s a needed alternative to coal-fired plants. Aerosols’ effect on wind speeds also may explain the reduction in the Asian seasonal monsoon and “disappearing winds” in China observed in other studies. Moreover, slack air currents may hurt energy efficiency in Europe, where countries such as Denmark and Germany have made major wind-power investments.
Slower winds evaporate less water from oceans, rivers, and lakes. Furthermore, the cooling of the ground reduces the evaporation of water in soil, according to the study.
The accumulation of aerosol particles in the atmosphere tends to make clouds retain water. Atmospheric water forms deposits on naturally occurring particles, like dust, to form clouds. However, if there is pollution in the atmosphere, the available water is spread thin over more particles, forming smaller droplets. These smaller droplets take longer to coalesce and form raindrops. In fact, rain may not ever happen, because the clouds exist longer and may move to drier air zones and evaporate, according to the findings.
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Glacial Ice Loss
Picked Up Pace in 2005
Mountain glaciers around the world continue to melt, with new, still tentative figures for 2005 indicating an average thickness reduction for a set of reference glaciers of 0.6 meter water equivalent (w.e.). On average, 1 meter water equivalent corresponds to ice thickness of 1.1 meters.
This data, published by the World Glacier Monitoring Service (WGMS) in Zurich, Switzerland, confirm the trend of accelerated ice loss during the past 25 years and brings the average thickness loss since 1980 to about 9.6 meter w.e. for 30 reference glaciers in nine mountain ranges.
The average mass balance of the reference glaciers continues to decrease, with the average annual ice loss since the year 2000 at 1.6 times more than the average of the 1990s and three times the loss rate of the 1980s.
Comprehensive data for the year 2006 are not yet available, but as it was one of the warmest years in many parts of the world, the downward trend is expected to continue.
“Today, the glacier surface is much smaller than in the 1980s, and this means that the climatic forcing has continued since then. The recent increase in rates of ice loss over reducing glacier surface areas leaves no doubt about the accelerated change in climatic conditions,” said Michael Zemp, a glaciologist and research associate at WGMS.
Glacier mass balance data reported by WGMS serves as a factor in the United Nations Environment Programme’s Global Environmental Outlook report published annually.
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Herbicide Exposure Linked to
Reduced Protein in Algae
Use of the common herbicide altrazine has been linked to potential decreases in protein levels and consequently smaller sizes of phytoplankton – a type of free-floating algae that forms the base of the food chain for many aquatic animals.
This conclusion came from researchers at the National Oceanic & Atmospheric Administration’s (NOAA) National Centers for Coastal Ocean Science. Published in the January issue of the journal Pesticide-Biochemistry and Physiology, the study indicates protein levels in phytoplankton significantly decreased as a result of 96 hours of atrazine exposure.
Research was conducted on five algal species exposed to atrazine levels within the range of atrazine concentrations that have been measured in the estuarine environment. In three of five species tested, the amount of energy converted into protein from photosynthesis significantly decreased. Photosynthesis is the process in green plants by which light energy is used to convert water and carbon dioxide into organic materials, producing oxygen as a byproduct.
Atrazine is one of the most heavily used herbicides in the United States. It acts as an inhibitor of photosynthesis by preventing the transfer of energy in certain plant species. NOAA researchers have observed significant decreases in size of phytoplankton species exposed to atrazine, which may negatively affect higher-level species in the aquatic food chain as this crucial food source loses nutritional value.
“Many aquatic animals such as clams and oysters rely on phytoplankton as a food source,” said Marie DeLorenzo, NOAA research ecologist. “Disruption to the cellular composition of phytoplankton species may negatively affect nutritional levels of the plant, resulting in decreased growth rates for those animals that consume phytoplankton.”
Mike Fulton, a NOAA research fishery biologist, said that the use of atrazine as a growth inhibitor in broadleaf and grassy weeds is an accepted practice beneficial to farmers and landscape professionals. “But it is equally important to gain an understanding of the potential effects of this herbicide on nontarget aquatic plant species,” he said.
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Mercury Concentrations
Common in Western U.S. Fish
In a study of more than 600 rivers and streams in the western United States, researchers at Oregon State University (OSU) and the U.S. Environmental Protection Agency (EPA) found widespread mercury concentrations in fish.
Though few of the more than 2,700 fish analyzed in the study contained alarmingly high levels of mercury, prevalence of the element throughout 12 western states surprised researchers, according to a Jan. 23 announcement by OSU.
“Mercury is everywhere,” said Alan Herlihy, a research associate professor with OSU’s Department of Fisheries and Wildlife and one of the authors of the study. “It was literally in every fish we sampled, which suggests an atmospheric source. There also tended to be a noticeable difference between ‘piscivores,’ or fish-eating fish, and nonpiscivores such as salmonids.”
The researchers found that mercury levels were much higher in the larger fish-eating species, including bass, walleye, northern pike, and pikeminnow. These piscivores are not as widespread throughout western river systems as salmonids, such as rainbow and cutthroat trout, which had lower levels of mercury.
The study concluded the risk to humans who eat fish from the streams is fairly low. The researchers compared the mercury levels in most of the larger piscivorous fish they analyzed to that found in cans of store-bought tuna. Consumption of those products in moderation is considered safe, although infants, young children, pregnant women, and persons who eat a lot of fish have higher risk levels than the general population.
Less clear is the impact of mercury on fish-eating birds and mammals, said Robert Hughes, also an author of the paper and an OSU fisheries and wildlife research associate professor.
“If I were a mink or an otter, I'd be concerned,” Hughes said. “Those guys are loading up on fish containing mercury, and we don’t really know at what levels they may be affected. In birds, the effects of mercury contamination are neurological or behavioral – and often subtle. They may not clean their young, or they may leave eggs unattended in their nests.
“We simply haven’t done enough studies to know all of the impacts, especially on fish-eating animals,” Hughes added.
The study, based on data collected from EPA’s Environmental Monitoring and Assessment Program, encompassed nearly 188,000 miles of perennial streams and rivers in the western United States. Selection of the more than 600 creek and river sample sites was random to address regional questions about the prevalence of mercury contamination among fish in western rivers.
Mercury entering the water via the atmosphere comes from a variety of natural and human-made sources, the researchers said, including coal power plants from as far away as China, the burning of heavy oils and other fossil fuels, and even forest fires.
In the survey, the researchers found 13 fish from eight different sites that had very high mercury concentrations – levels of 1.0 microgram or higher—likely indicating a point source. These high levels could be caused by nearby mines, dump sites, or gravel pits, the researchers added.
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Scientists Identify Factors in
Toxic Algal Bloom Production
Scientists have pinpointed a toxin produced by Pfiesteria piscicida and Pfiesteria Shumway that in turn results in algal bloom. In a statement released Jan. 16, National Oceanic & Atmospheric Administration (NOAA) scientists concluded that metal-mediated free radical production transforms Pfiesteria into toxic organisms that can cause estuarine fish kills. These free radicals are activated chemical byproducts of biological activity.
“NOAA is committed to supporting the research needed to find answers to the Pfiesteria puzzle,” said Conrad C. Lautenbacher Jr., undersecretary of commerce for oceans and atmosphere and NOAA administrator. “The economic impact of harmful algal blooms in the United States averages $49 million yearly, but individual outbreaks can be extremely costly. The 1997 Pfiesteria bloom in Chesapeake Bay cost the Maryland seafood and recreational fishing industries almost $50 million in just a few months.”
The team, led by Peter Moeller of the NOAA Center for Coastal Environmental Health and Biomolecular Research in Charleston, S.C., identified new components, with emphasis on heavy metals, contributing to Pfiesteria toxin mortalities in certain estuarine fish species.
Laboratory experiments were performed using sheepshead minnows -- a species found in brackish conditions and tolerant of low-oxygenated water that may otherwise be inhospitable to other fish species. The experiments used variations in temperature, Pfiesteria bacteria, heavy metals commonly found in estuaries, brackish water, and natural light.
“Definitive mortality rates in fish occurred within six hours under precise conditions of metals, temperature, light, and Pfiesteria toxin,” said Moeller, a NOAA organic chemist. “After activation, the Pfiesteria toxins quickly decomposed, rendering the toxin undetectable.”
Moeller’s collaborators at the National Institute of Standards and Technology and the Medical University of South Carolina were able to characterize the metal-containing toxin using five distinct instrumental methods: nuclear resonance spectroscopy; inductively coupled plasma mass spectrometry; liquid chromatography particle-beam glow discharge mass spectrometry; electron paramagnetic resonance spectroscopy; and X-ray absorption spectroscopy. The results showed that the high toxicity of the metal-containing toxins is due to metal-mediated free radical production.
This activity can explain the toxicity of Pfiesteria, as well as the previously reported difficulty in observing the molecular target due to the ephemeral nature of radical species. These findings represent the first formal isolation and characterization of a radical forming toxic organic-ligated metal complex from an estuarine/marine dinoflagellate (single-celled planktonic organisms, chiefly marine, characterized by twirling motion and whip-like flagella).
The findings add an increased understanding of how metals, commonly found in the estuarine and marine environment, interact with the biological systems in the environment and how those interactions potentially impact both marine animals and human health.
The discovery may not only help solve one of the more intriguing scientific puzzles of the 1990s but also could lead to a new way of looking at the toxicity of harmful algal blooms. These blooms are increasing globally and threatening human and marine health.
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Study Finds Contamination
in Chesapeake Bay Tributaries
The major portion of the Chesapeake Bay, called the “mainstem,” has minimal sediment contamination. However, localized areas of the bay show elevated contaminant levels, according to a report published in January by the National Oceanic & Atmospheric Administration (NOAA).
Researchers from the NOAA National Centers for Coastal Ocean Science collected sediment samples from the Chesapeake Bay between 1998 and 2001 to determine any contamination by toxic chemicals. Their report, “Magnitude and Extent of Contaminated Sediment and Toxicity in Chesapeake Bay,” covers the mainstem of the Chesapeake Bay, along with its major western tributaries -- the Patuxent, Potomac, Rappahannock, York, and James rivers.
Toxic contaminants enter the bay from these and other tributaries, as well as from a variety of other sources, including windblown dust, stormwater runoff, spills, and direct discharge.
NOAA’s study examined various toxic contaminants found in Chesapeake Bay, including metals, polychlorinated biphenyls, persistent chlorinated pesticides, and polycyclic aromatic hydrocarbons. Scientists studied the organisms (benthos) living in the sediments within the research area to determine which animals live where. Then they conducted laboratory studies to assess how the contaminants affect estuarine organisms. The report summarizes where contamination exists and the correlation between benthic community impacts, observed toxicity, and contaminant levels.
While the study found the Chesapeake mainstem relatively uncontaminated, most sample locations in the major western tributaries had higher contaminant concentrations than the mainstem. The study also found the richness, abundance, and diversity of benthic (the lowest level of a body of water) species declined as contamination levels and toxicity increased. Although the types of fine sediments where contaminants accumulate generally are areas aquatic animals avoid, when sediment type was taken into account, researchers found toxicity still affected benthic communities.
“Sediment contaminants often pose ecological and human health risks through degraded habitats, loss of fauna, contaminants accumulating in the coastal food chain, and human consumption of contaminated fish and wildlife,” said Ian Hartwell, an ecologist with the NOAA National Status and Trends Program’s Bioeffects Project.
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New Drumlin in Antarctica
Could Factor into Sea-Level Changes
Scientists have discovered a warehouse-sized drumlin – a mound of sediment and rock – actively forming and growing under the ice sheet in Antarctica. Its discovery, and the rate at which it was formed, sheds new light on ice-sheet behavior and could have implications for predicting how ice sheets contribute to sea-level rise. The results were published in February in the journal Geology.
Drumlins are landscape features scoured by past ice sheets and formed during the last ice age. They form under the ice and rock and slow down the rate at which the ice can flow.
Scientists from British Antarctic Survey (BAS), Swansea University in the United Kingdom, and NASA’s Jet Propulsion Laboratory-Pasadena used a new technique of time-lapse seismic surveys to find the drumlin and determine how it formed over time. The most recent data, from 2004, revealed a large lump of sediment not present in 1997 when the area was previously surveyed.
“This is the first time anyone has observed a drumlin actually forming under the ice. These results will help us interpret the way ice sheets behaved in the past, and crucially, will help predict how they might change in the future,” said Andy Smith of BAS, lead author of the report.
The drumlin grew 10 times faster than the team expected, giving a new and important insight into the drag on the underside of the ice and hence how fast ice sheets are able to flow. The study took place on the Rutford Ice Stream – a 2-kilometer-thick, fast-flowing ice stream draining part of the West Antarctic ice sheet. The team used seismic reflection data gathered three times over the last 13 years to map the changes beneath the ice.
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Chemicals in Potomac River Alter Fish Sex Characteristics
The discovery of a high incidence of intersex, or male fish exhibiting female characteristics, in smallmouth bass of the Potomac River Basin has prompted an investigation of water quality and wastewater discharge into the upper Potomac and blood-plasma studies on this fish species.
U.S. Geological Survey (USGS) scientists recently discovered pesticides, flame retardants, and personal-care products containing known or suspected endocrine-disrupting chemicals in several tributaries to the Potomac River and in the smallmouth bass that inhabit them. An organism’s endocrine system excretes hormones that govern many functions, including sexual and reproductive characteristics. Endocrine disrupters in the environment include pharmaceuticals in untreated wastewater and agricultural runoff.
Agricultural, industrial, and household products often contain compounds that mimic estrogen when ingested. Endocrine disrupters of this type may contribute to the high percentage of male smallmouth bass found in the Potomac that exhibit female characteristics.
“We analyzed samples of 30 smallmouth bass from six sites, including male and female fish without intersex and male fish with intersex,” said Douglas Chambers, USGS scientist and lead investigator, in a Jan. 17 press release from USGS. “All samples contained detectable levels of at least one known endocrine-disrupting compound, including samples from fish without intersex.”
Known or suspected endocrine-disrupting chemicals from pesticides, flame-retardants, and personal-care products also were present in water samples taken from all eight sites, including those where fish did not exhibit intersex. Wastewater from several sites that discharge municipal effluent or from sites contributing runoff was examined to identify point sources of these compounds. Antibiotics were found in wastewater samples, with municipal effluent having at least seven such compounds, but were not detected in water from other sites.
The reproductive anomalies in the Potomac’s smallmouth bass population were discovered by accident. In 2003, scientists investigating massive fish kills and widespread lesions found oocytes, precursors of egg cells that females normally produce, while looking at tissues from the testes of male fish under the microscope.
High intersex occurrence in aquatic species has been documented at other locations in the United States and in Europe. It is not unique to the Potomac Basin or to smallmouth bass. Previous studies have found that known or suspected endocrine disrupters are widespread in the environment.
The USGS continues to examine the occurrence of known or suspected endocrine disrupters in the Potomac Basin to determine the potential for these compounds to interfere with the development and reproduction of aquatic life.
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This article originally appeared in the 03/01/2007 issue of Environmental Protection.