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:10/13/2017)... ... October 13, 2017 , ... Yisrayl Hawkins, Pastor and Overseer ... one of the most popular and least understood books in the Holy Scriptures, Revelation. ... descriptions that have baffled scholars for centuries. Many have tossed it off as mere ...
(Date:10/13/2017)... ... October 13, 2017 , ... Coveros, a leader in agile ... a contract by the Center for Medicare and Medicaid Services (CMS). The Enterprise ... use of Agile methodologies in a consistent and high value manner across CMS ...
(Date:10/13/2017)... ... , ... “America On The Brink”: the Christian history of the United States ... creation of published author, William Nowers. Captain Nowers and his wife, Millie, have ... thirty years in the Navy. Following his career as a naval aviator and ...
(Date:10/12/2017)... ... October 12, 2017 , ... CitiDent and San Francisco ... using cutting-edge Oventus O2Vent technology. As many as 18 million Americans are estimated ... in breathing. Oral appliances can offer significant relief to about 75 percent of ...
(Date:10/12/2017)... , ... October 12, 2017 , ... ... to meet the demand of today’s consumer and regulatory authorities worldwide. From Children’s ... experts and tested to meet the highest standard. , These products are ...
Breaking Medicine News(10 mins):
(Date:10/4/2017)... 4, 2017 OBP Medical , ... medical devices, today announced regulatory approval from ... (or Agência Nacional de Vigilância Sanitária (ANVISA)) to ... surgical retractor with integrated LED light source and ... and exposure of a tissue pocket or cavity ...
(Date:10/2/2017)... -- Eli Lilly and Company (NYSE: LLY ) ... of 2017 on Tuesday, October 24, 2017. Lilly will ... the investment community and media to further detail the ... begin at 9 a.m. Eastern time. Investors, media and ... the conference call through a link that will be ...
(Date:10/2/2017)... Halo Labs announces the European launch of their new low volume, ... 2017 in Cambridge, U.K on October 4th. ... samples with unprecedented speed and sensitivity while using far less sample ... ... system ...
Breaking Medicine Technology: