Navigation Links
Large source of nitrate, a potential water contaminant, found in near-surface desert soils
Date:2/29/2008

RIVERSIDE, Calif. A UC Riverside-led study in the Mojave Desert, Calif., has found that soils under desert pavement have an unusually high concentration of nitrate, a type of salt, close to the surface. Vulnerable to erosion by rain and wind if the desert pavement is disrupted, this vast source of nitrate could contaminate surface and groundwaters, posing an environmental risk.

Study results appear in the March issue of Geology.

Desert pavement is a naturally occurring, single layer of closely fitted rock fragments. A common land surface feature in arid regions, it has been estimated to cover nearly half of North Americas desert landscapes.

Nitrate, a water soluble nitrogen compound, is a nutrient essential to life. It is also, however, a contaminant. When present in excess in aquatic systems, it results in algal blooms. High levels of nitrate in drinking water have been associated with serious health issues, including methaemoglobinaemia (blue baby disease, marked by a reduction in the oxygen-carrying capacity of blood), miscarriages and non-Hodgkins lymphoma.

Salts, including nitrate, are formed in deserts as water evaporates on dry lake beds. These salts then get blown on to the desert pavement by winds. Other contributors of nitrate to desert pavement soils are atmospheric deposition (the gradual deposition of nutrient-rich particulate matter from the air), and soil bacteria, which convert atmospheric nitrogen into nitrate that is usable by plants and other organisms.

Ordinarily, in moist soils, plants and microbes readily take up nitrate, and water flushing through the soils leaches the soils of excess nitrate.

But desert pavement, formed over thousands of years, impedes the infiltration of water in desert soil, restricting plant development and resulting in desert pavement soils becoming nitrate-rich (and saltier) with time.

After water, nitrogen is the most limiting factor in deserts, affecting net productivity in desert ecosystems, said Robert Graham, a professor of soil mineralogy in the Department of Environmental Sciences and the lead author of the research paper. The nitrate stored in soils under desert pavement is a previously unrecognized vast pool of nitrogen that is particularly susceptible to climate change and human disturbance. Moister climates, increased irrigation, wastewater disposal, or flooding may transport high nitrate levels to groundwater or surface waters, which is detrimental to water quality.

In their study, Graham and his colleagues sampled three widely separated locations with well-developed desert pavement in the Mojave Desert. The locations were selected to represent a variety of landforms commonly found in the desert. The researchers found that the nitrate they observed in association with desert pavement was consistent across the landforms.

Deserts account for about one-third of Earths land area, Graham said. If our findings in the Mojave can be extrapolated to deserts worldwide, the amount of nitrate and nitrogen stored in near-surface soils of warm deserts would need to be re-estimated.

Graham and his team of researchers found that nitrate concentration in soils under desert pavement in the Mojave reached a maximum (up to 12,750 kilograms per hectare) within 0.1 to 0.6 meter depth. In contrast, at each location they studied, the soils without desert pavement had relatively low nitrate concentrations (80 to 1500 kilograms per hectare) throughout the upper meter. In these nonpavement locations, water was able to infiltrate the soil and transport the nitrate to deeper within the soil, Graham explained.

The researchers note in the paper that desert land use road construction, off-road vehicle use, and military training often disrupts fragile land surfaces, increasing surface erosion by rain and wind. According to them, nitrogen-laden dust transported by wind from disturbed desert pavement soils may impact distant nitrogen-limited ecosystems, such as alpine lakes.

Furthermore, the researchers note that increased soil moisture resulting from climate change increases the potential for denitrification a naturally-occurring process in soil, where bacteria break down nitrates to return nitrogen gas to the atmosphere. Denitrification also produces nitrous oxide, a major greenhouse gas, Graham said.

Next in their research, Graham and his colleagues will examine the spatial distribution of desert pavement throughout the Mojave Desert to explore how different levels of nitrate are associated with different kinds of desert pavement. Together with UCRs David Parker, a professor of soil chemistry, they will look in the desert also for perchlorate, which may be associated with nitrate.


'/>"/>

Contact: Iqbal Pittalwala
iqbal@ucr.edu
951-827-6050
University of California - Riverside
Source:Eurekalert  

Related medicine news :

1. Super Prostate Product - More Beta-sitosterol, all-natural Best Prostate(TM) Formula for Enlarged Prostate and BPH - Increases Urine Flow, Reduces Waking and Improves Quality of Life
2. Crdentia Selected by Leading Staffing Vendor to Provide Health Care Staffing Services to One of the Largest Hospital Chains in the U.S.
3. $30.3 Million Jury Verdict Believed to Be New Jerseys Largest
4. Worlds Largest Disabled Ski Clinic at Snowmass, Colo.
5. In jazz improv, large portion of brains prefrontal region takes 5 to let creativity flow
6. Significant Growth for Pinstripe Leads to Need for Larger Facility
7. Large changes needed to address global obesity epidemic
8. NIH report on intracranial stent points out need for upcoming large-scale clinical trial
9. Patients with larger social networks may fare better after an operation
10. Illinois Meth Project Launches Large-Scale Meth Prevention Campaign
11. EBRI Policy Forum: Large Employers Continue to Offer Health Benefits
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Large source of nitrate, a potential water contaminant, found in near-surface desert soils
(Date:6/25/2016)... ... June 25, 2016 , ... ... issues and applications at AcademyHealth’s Annual Research Meeting June 26-28, 2016, at the ... several important health care topics including advance care planning, healthcare costs and patient ...
(Date:6/25/2016)... ... June 25, 2016 , ... As a lifelong Southern Californian, Dr. Omkar Marathe ... from the David Geffen School of Medicine at UCLA. He trained in Internal Medicine ... his fellowship in hematology/oncology at the UCLA-Olive View-Cedars Sinai program where he had the ...
(Date:6/24/2016)... ... ... Those who have experienced traumatic events may suffer from a complex set of ... or alcohol abuse, as a coping mechanism. To avoid this pain and suffering, Serenity ... event. , Trauma sufferers tend to feel a range of emotions, from depression, guilt, ...
(Date:6/24/2016)... (PRWEB) , ... June 24, 2016 , ... ... now offering micro-osteoperforation for accelerated orthodontic treatment. Dr. Cheng has extensive experience with ... Damon brackets , AcceleDent, and accelerated osteogenic orthodontics. , Micro-osteoperforation is a ...
(Date:6/24/2016)... ... June 24, 2016 , ... The Haute Beauty Network, ... M. Weintraub as a prominent plastic surgeon and the network’s newest partner. ... the most handsome men, look naturally attractive. Plastic surgery should be invisible.” He ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... 2016  Astellas today announced the establishment of Astellas Farma Colombia (AFC), a new affiliate with operations headquartered in ... America . ... ... ... ...
(Date:6/23/2016)... , June 23, 2016  Guerbet announced today that ... Supplier Horizon Award . One of ... was recognized for its support of Premier members through ... clinical excellence, and commitment to lower costs. ... this recognition of our outstanding customer service from Premier," ...
(Date:6/23/2016)... , June 23, 2016 Research ... "Surgical Procedure Volumes: Global Analysis (United States, China, Japan, ... report to their offering. ... tool for healthcare business planners, provides surgical procedure volume ... surgery trends with an in-depth analysis of growth drivers ...
Breaking Medicine Technology: