News
PNNL Researchers Develop Technology For Removing Perchlorate From Water
On July 21, researchers at Pacific Northwest National Laboratory (PNNL) announced
the demonstration of a new, environmentally friendly process for treating water
contaminated by perchlorate, a toxic chemical that has been found in drinking
water in 35 states.
Perchlorate is used in rocket fuel, fireworks, and defense manufacturing, and
groundwater contaminated by the chemical is difficult to treat. High levels
of perchlorate have been associated with thyroid disease, and possibly cancer
and other health problems. Contamination is especially widespread in California,
which has a high number of U.S. military bases.
The conventional method for treating perchlorate-contaminated water employs
an ion exchange resin. Regenerating the resin requires flushing with an acidic
solution, which results in large quantities of secondary waste, the researchers
said.
The PNNL method is an electrically controlled anion exchange process.
"The technology is unique in that it uses an electric current to regenerate
the resin and release the perchlorate without producing a lot of secondary waste,"
said Yuehe Lin, lead researcher, adding that the process is "green"
because it produces so little waste.
The technology is available for licensing and joint research opportunities through
Battelle, which operates PNNL for the U.S. Department of Energy and facilitates
the transfer of lab-created technologies to the marketplace.
To create the new process, Lin and his colleagues induced a positive charge
to an electrically conducting polymer, such as a polypyrrole, that selectively
attracts the negatively charged perchlorate ions. Application of an electric
current releases the trapped perchlorate ions for disposal. Now neutral, the
polymer can be reverted to a positively charged surface and reused.
The scientists increased the amount of perchlorate that can be captured by depositing
the polymer as a polypyrrole thin film on a matrix of carbon nanotubes, creating
a porous conductive nanocomposite.
"The high surface area of the carbon nanotubes provides an ideal matrix
for the polymer," Lin said, noting that the polymer is electrodeposited
on the carbon nanotubes through in-situ polymerization.
The porous surface created by the carbon nanotubes also gives the technology
a longer life cycle because the polymer is more stable on the nanotube matrix
than it would be on a flat, conducting substrate.
The electrically controlled anion exchange technology can be used to remove
other contaminants, such as cesium and chromium. A radioactive material common
to nuclear waste sites, cesium could be used by terrorists to build dirty bombs
or contaminate drinking water. Chromate is a toxic form of chromium that is
readily absorbed by the body.
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Marine 'dead zone' off Oregon is spreading
A hypoxic "dead zone" has formed off the Oregon Coast for the fifth
time in five years, according to researchers at Oregon State University.
A fundamental new trend in atmospheric and ocean circulation patterns in the
Pacific Northwest appears to have begun, scientists say, and apparently is expanding
its scope beyond Oregon waters.
This year for the first time, the effect of the low-oxygen zone is also
being seen in coastal waters off Washington, researchers at OSU and the Olympic
Coast National Marine Sanctuary indicate.
There have been reports of dead crabs stretching from the central Oregon
coast to the central Washington coast. Some dissolved oxygen levels at 180 feet
have recently been measured as low as 0.55 milliliters per liter, and areas
as shallow as 45 feet have been measured at 1 milliliter per liter.
These oxygen levels are several times lower than normal, and any dissolved
oxygen level below 1.4 milliliters per liter is hypoxic, capable of suffocating
a wide range of fish, crabs, and other marine life.
"There is a huge pool of low-oxygen water off the central Oregon
coast with values as low as 0.46 milliliters per liter," said Francis Chan,
marine ecologist in the OSU Department of Zoology and with the Partnership for
Interdisciplinary Studies of Coastal Oceans (PISCO), a marine research consortium
at OSU and other universities along the West Coast. "OSU researchers have
documented this year's region of low-oxygen bottom waters from Florence to Cascade
Head. The lack of consistent upwelling winds allowed a low-oxygen pool of deep
water to build up. Now that the upwelling-favorable winds are blowing consistently,
we're seeing that pool of water come close to shore and begin to suffocate marine
life. If these winds continue to blow, we expect to see continued and possibly
significant die-offs."
As events such as this become more regular, researchers say, they appear
less like an anomaly and more like a fundamental shift in marine conditions
and ocean behavior. In particular, a change in intensity and timing of coastal
winds seems to play a significant role in these events.
"We're seeing wild swings from year to year in the timing and duration
of winds favorable for upwelling," said Jack Barth, an oceanographer with
PISCO and the OSU College of Oceanic and Atmospheric Sciences. "This change
from normal seasonal patterns and the increased variability are both consistent
with climate-change scenarios."
Barth and his colleagues are working on new circulation models that may
allow scientists to predict when hypoxia and these "dead zones" will
occur. No connection has been observed between these events and other major
ocean cycles, such as El Niño or the Pacific Decadal Oscillation.
The lack of wide-scale ocean monitoring makes determining the size and
movement of the dead zone difficult, although some new instrumentation being
used this year seems to be helping. Dissolved oxygen sensors have been deployed
on the sea floor, both close to shore and in 260 feet of water off Newport,
some of which are sending data in near real-time.
In addition, a new underwater unmanned vehicle equipped with sensors to
measure temperature, salinity, chlorophyll, and dissolved oxygen is routinely
sampling across central Oregon waters.
During normal years, cold water rich in nutrients but low in oxygen upwells
from the deep ocean off Oregon, mixes with oxygen-rich water near the surface,
causes some phytoplankton growth, and provides the basis for a thriving fishery
and healthy marine food chain. During dead zone periods, some of the normal
processes -- including wind and current conditions -- can change. This allows
huge masses of plant growth to die, decay, and in the process consume even more
of the available oxygen near the sea floor, causing hypoxic conditions for marine
life.
The first event in 2002 caused a massive die-off of fish and invertebrate
marine species on the central Oregon coast. Less severe and somewhat different
events occurred in 2003, 2004, and 2005.
The 2006 "dead zone" has a wider north-south extent. Some crabbers
in the central Washington coast reported all dead crabs in pots at depths of
about 45 to 90 feet, north of the Moclips River. Large numbers of dead Dungeness
crab have been reported on the beach as far north as Kalaloch. Numerous species
of bottom fish have been found dead on the beach south of the Quinault River
in Washington.
In Oregon, the most vulnerable area in recent years has been the central
third of the coast between about Newport and Florence, where conditions seem
to be conducive to the development of low-oxygen waters. It's not always easy
to measure the biological impact of the dead zones, because many dead animals
may be washed out to the deep sea. But researchers say that this year's event
may ultimately be as severe as the first one in 2002, although it reflects slightly
different wind and ocean current conditions.
Researchers say that it's difficult to tell what long-term ecological
impacts these dead zone events may have on marine ecosystems.
"Many marine species live in fairly specialized ecological niches
and any time you change the fundamental physics, chemistry and nature of the
system, it's a serious concern," Barth said.
Jane Lubchenco, the Valley Professor of Marine Biology at OSU and principle
investigator for PISCO, also said that the biological monitoring of species
health and impacts in the nearshore Pacific Ocean is "grossly inadequate,"
making it difficult to evaluate the long-term impacts of low-oxygen and other
events.
Study Suggests Pharmaceuticals May Not Pose Major Risk To Aquatic Environment
A Canadian study of high-use drugs released from eight municipal wastewater
treatment plants suggests that invertebrates, bacteria, and plants in the aquatic
environment are unlikely to be affected.
In Canada, approximately 24,000 products -- including human pharmaceutical
and biological drugs, veterinary drugs, and disinfectants -- are registered
on Health Canada's Drug Product Database. None of these pharmaceuticals is absorbed
entirely by the body; they often leave through urine and fecal matter. Domestic
waste streams carry the excreted drugs to municipal wastewater treatment plants,
private septic systems, or receiving waters without treatment.
Though sewage treatment plants can remove or degrade some of the drug
compounds, many drugs and by-products are not removed effectively. Hence the
major source of pharmaceuticals in the aquatic environment is from sewage treatment
plants.
Across Atlantic Canada, the study's researchers found 10 acidic and two neutral
pharmaceuticals in the effluents of eight sewage treatment plants. In the large
bodies of receiving water, drugs generally were not detected at significant
concentrations. However, in the small receiving streams, drug residues continued
downstream for 17 kilometers. Based on the results of laboratory toxicity tests,
the researchers concluded that the concentrations measured were not causing
harm.
The study is published in the latest issue of Environmental Toxicology and
Chemistry (Vol. 25(8): 2163-2176).
For more information, click
here.
U.S., Israel Collaborative Effort Targets Most Promising Areas For
Water Treatment Using Nanotechnologies
Water researchers from leading institutions in Israel and the United States
announced on July 10 they have targeted four "cutting-edge" projects
for collaborative research between the two countries.
Their selection is one outcome of a bi-national workshop held in Washington,
D.C., in mid-March, organized by the U.S. and Israeli national nanotechnology
initiatives, and the Center of Advanced Materials for Purification of Water
with Systems (WaterCAMPWS) at the University of Illinois.
Professor Rafi Semiat, director of the Grand Water Research Institute
at the Technion Israel Institute of Technology and a workshop organizer, said
that while the group will promote all 12 nanotech-based projects that were outlined
at the workshop, special focus is being given to four projects that can provide
extraordinary benefits for water purification, and that have the potential to
be applied commercially within the next five years.
"Both countries see the target projects not only as very exciting,
potential breakthroughs, but also as applied research that can get funded and
get commercialized quickly," Semiat said.
The target projects focus on distinct nanotechnology-based solutions that
were outlined at the bi-national workshop: membranes and membrane processes,
biofouling and disinfection, contaminants removal, and environmental monitoring
and sensors.
The four targeted projects are:
-- Development of new, porous polymer-based, ultra-filtration membranes with
special coatings that exhibit higher flux and higher resistance to contamination,
as well as robust molecular sieving abilities. The project will create and test
self-assembling membranes with very stable transport channels that reduce biofouling
and may also be capable of self-cleaning.
-- Development of coatings with antimicrobial capabilities that can minimize
biological attachment and biofilm formation that can be applied to current generation
membranes that are used for drinking water, wastewater, and desalination.
-- Study of mixed metal-oxide, nanostructured materials for the destruction
of biological toxins in surface water and groundwater, using photocatalysis
and oxidation. The project will provide data for optimizing the use of these
materials in various environments.
-- Development of whole-cell microbial biosensors to detect minute metabolite
excretions from newly forming biofilms. The project will examine the mechanisms
of biological attachment to surfaces, identify its biochemical signals, and
develop nanoscale sensors that can be applied to membrane surfaces, enabling
optimized maintenance for water purification membranes and significant extension
of membrane lifetimes.
Rich Sustich, industrial and governmental development manager for the
WaterCAMPWS and a workshop organizer, said that there is special excitement
over the proposed biosensor project, which may result in new tools and methods
for water systems operation and reduction of long-term maintenance costs.
"Today's water infrastructure is run on a one-size-fits-all concept,"
Sustich noted. "Systems are assembled from standard components, and maintenance
relies more on manufacturer's recommendations than on a direct understanding
of what's really happening during treatment. This works, but it's very wasteful."
Adding biosensing devices throughout the water treatment system will provide
direct awareness and interaction with the system in real time. The proposed
biosensors can eventually lead beyond passive sensing to the development of
"smart" membranes that react biologically to changes in the system's
environment, and perhaps even prevent biofilm and toxics formation without the
need for manual intervention, according to researchers.
Workshop participants agreed that such biosensing mechanisms could be
applied within 5 to 10 years, given the needed development resources.
Workshop sponsors are seeking approximately $600,000 to support the costs
of binational collaboration on all 12 projects, with funding to be matched equally
between Israeli and U.S. sources. Additional workshops are also planned.
For more information, click here.
Researchers: Gypsum Helps Curb Phosphorus Runoff
Gypsum showed the most promise in an Agricultural Research Service (ARS) study
examining the ability of soil additives to curb runoff of phosphorus from farm
fields into the nation's waters, ARS officials announced on June 20.
In research led by agronomist David Brauer of the ARS Dale Bumpers Small
Farms Research Center in Booneville, Ark., the soft, widely distributed mineral
was the only one of three soil amendments tested that reduced soluble soil phosphorus
in a field containing more than 10 times the amount normally found in soils.
The study was done by Brauer, animal scientist Glen Aiken of the ARS Forage-Animal
Production Research Unit in Lexington, Ky., soil scientist Daniel Pote of the
Booneville center, and colleagues. The researchers examined how well gypsum,
alum, and ground-up wastepaper kept phosphorus from leaching from farmland.
Testing was done near Kurten, Texas, on land that has received manure applications
from dairy and egg-laying operations for more than 40 years.
Excessive use of manures and other fertilizers can significantly increase
phosphorus amounts in the soil. A valuable crop nutrient, phosphorus can run
off and damage waterways by promoting accelerated growth of algae and plants
in streams and lakes. This can deplete oxygen levels in water bodies and adversely
impact living aquatic resources.
The researchers amended the soil annually for three years. They found
that applying 5,000 pounds of gypsum per acre was most effective in reducing
soil-test values for phosphorus. According to Brauer, reductions in dissolved
reactive phosphorus seemed to be dependent on continual applications of gypsum.
Commonly found in sedimentary environments, gypsum is also a byproduct
of coal-burning operations.
Brauer explained that gypsum curtails the amount of phosphorus lost by
promoting the binding together of soil particles, thus reducing phosphorus carried
along with sediment. He added that applying wastepaper product containing aluminum,
the active ingredient in alum, can effectively curb phosphorus, but the large
amounts necessary can be impractical.
For more information, click
here.
Catalytic Process Breaks Down Hormones In Wastewater
Scientists from Carnegie Mellon University and the U.S. Department of Agriculture
(USDA) announced on June 26 they have found that a rapid, environmentally friendly
catalytic process involving Fe-TAML® activators and hydrogen peroxide breaks
down two types of estrogenic compounds. These natural and synthetic estrogenic
compounds can mimic or block the activities of hormones in wildlife and humans,
which may disrupt the normal functions of the endocrine system and impair development.
They could also contaminate drinking water.
The results were presented by Nancy Shappell, a research physiologist with USDA's
Agricultural Research Service (ARS), on June 29, at the tenth annual Green Chemistry
and Engineering Conference in Washington, D.C. Shappell presented her paper,
"Degradation of Estradiol and Ethinylestradiol With an Fe-TAML® Oxidant
Activator and Hydrogen Peroxide," during the Frontiers in Green Chemistry
and Green Engineering section of the conference. Estradiol is a natural form
of the female hormone estrogen, and ethinylestradiol is a synthetic version
used in contraceptives.
Fe-TAML (tetra-amido macrocyclic ligand) activators, which are synthetic catalysts
made with elements found in nature, originated at Carnegie Mellon's Institute
for Green Oxidation Chemistry under the leadership of Terry Collins, the Thomas
Lord Professor of Chemistry in the Mellon College of Science.
"Environmental studies on various wildlife species have shown evidence
that endocrine disruptors interfere with reproductive, immune, and neurological
capabilities, and cause developmental abnormalities," Collins said. "We
need to quickly develop a suite of standardized assays that test for estrogen-like
activity of introduced chemicals and their byproducts so that anyone developing
a new chemical technology can assess whether or not their technology is associated
with endocrine disruption."
Waste from animal-rearing facilities across the United States constitutes a
major concentrated source of estrogens. Millions of pigs housed in these facilities
produce tons of waste products laden with estrogens that can enter the water.
In addition, synthetic versions of estrogen found in birth control pills can
enter surface water as a result of incomplete wastewater treatment, according
to Shappell. Some scientists have suggested that these environmental estrogens
could interfere with estrogen-controlled systems in wildlife and humans, disrupting
innate regulatory mechanisms and leading to developmental disorders, infertility,
and other reproductive complications.
"Our results show that Fe-TAML activators are capable of breaking down
two types of estrogenic compounds found as contaminants in surface water,"
Shappell said. "These promising results also indicate the potential use
of Fe-TAML activators to destroy estrogenic compounds in municipal and agricultural
wastewaters."
Shappell and colleagues found that the Fe-TAML activator, used with hydrogen
peroxide, almost completely degraded estradiol and ethinylestradiol in the laboratory.
According to the researchers, ethinylestradiol is resistant to most biological
degradation processes, but Fe-TAML activators break down more than 95 percent
of this chemical within five minutes.
"Our next step would be to advance testing to the field. Fe-TAML activators
have been field-tested in the pulp and paper industry and textile industry with
promising results," said Colin Horwitz, research professor at Carnegie
Mellon. ARS scientists Pat Hunt and Kyoung Ro from the Florence, S.C., Coastal
Plains Plant, Soil and Water Research Center were instrumental in making the
connection between Shappell and the Institute for Green Oxidation Chemistry,
and will be involved in field-testing swine wastewater.
Past studies with Fe-TAML activators have shown their enormous potential to
provide clean, safe alternatives to existing industrial practices and provide
ways to remediate other pressing environmental problems that currently lack
solutions. Specific applications of Fe-TAML activators have included cleaning
wastewater from textile manufacturing, reducing fuel pollutants, treating pulp
and paper processing byproducts, and decontaminating a benign simulant of anthrax.
For more information, click
here.
Soybean Scraps Used To Develop Filtering Agent For Contaminated Water
Scientists have discovered that soybean hulls -- as well as leftover stalks
and stems from already-plucked corn and sugarcane plants -- could be used to
develop a filtering agent that can adsorb harmful levels of lead, chromium,
copper, and cadmium from contaminated water, Agricultural Research Service (ARS)
officials stated on June 21.
ARS chemists Wayne Marshall and Lynda Wartelle -- who work at the ARS
Southern Regional Research Center (SRRC) in New Orleans, La. -- have found that
it takes just two steps to convert these abundant crop residues into a powerful
magnet capable of snagging both positively and negatively charged particles
of heavy metals in water.
The material that they've succeeded in creating is known as a dual-functioning
ion-exchange resin. These resins -- which are commonly used for treating industrial
and municipal wastewaters and for recycling heavy metals from solutions -- are
typically effective in capturing only one kind of particle with either a positive
or negative charge.
But the SRRC researchers' resins can grab both. Additionally, Marshall has found
that they're more cost-effective than two synthetically made resins currently
in use.
Ion exchange resins work by swapping, or exchanging, the undesirable ions
in a water supply with benign ones. In a classic example of this interplay,
water softeners work by drawing out and replacing unwanted "hard water"
particles, like calcium and magnesium, with ions from sodium.
Marshall and Wartelle give their plant residues a negative charge by adding
citric acid, a common food industry additive. The positive charge comes from
choline chloride, which the researchers bind to plant fibers by adding DMDHEU
(or dimethyloldihydroxyethylene urea) -- a chemical that's already known for
making molecules stick. In the textile industry, it's the compound that helps
dye cling to cotton and wool fibers.
For more information, click
here.
This article originally appeared in the 11/01/2006 issue of Environmental Protection.