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:2/13/2016)... ... February 13, 2016 , ... Good ... the first in the area to offer AngioPlex™ Optical Coherence Tomography (OCT) Angiography, ... such as macular degeneration, diabetic retinopathy, and other vascular conditions. , In just ...
(Date:2/13/2016)... ... , ... Hidden Cypress in Sun City is the place to be on March 3rd to ... Weniger will be hosting this educational seminar from 5:30 p.m. – 7:00 p.m. Exciting ... pricing on offers. In addition, prizes will be given away and light refreshments will be ...
(Date:2/13/2016)... California (PRWEB) , ... February 13, 2016 , ... Valentine’s ... landing a date for the big day. A great outfit, flawless hair, and a ... they might as well resign themselves to a night at home with Rover. (Actually, ...
(Date:2/13/2016)... Washington, D.C. (PRWEB) , ... February 13, 2016 ... ... joined with Faces and Voices of Recovery, the leading national organization representing the ... paper urging candidates for public office to include Family Recovery in policies addressing ...
(Date:2/13/2016)... ... February 13, 2016 , ... Many individuals looking to lead a ... multitude of reasons. IsoPasta by Isolator Fitness has delved into this niche allowing ... without the high-carb repercussions. IsoPasta has 30 grams of protein and only 7 ...
Breaking Medicine News(10 mins):
(Date:2/12/2016)... N.C. , Feb. 12, 2016  Clinical Affairs leaders at ... presence in emerging areas of the world. While some companies have ... lag in their clinical activity in countries such as ... China and India ... market products in those countries. --> China ...
(Date:2/12/2016)... 2016   National Community Pharmacists Association (NCPA) ... the following statement today in response to the detailed ... Centers for Medicare & Medicaid Services (CMS) and conducted ... and others: patient advocacy organizations and ... the full CMS analysis. Our initial reaction is that ...
(Date:2/12/2016)... 12, 2016  This month,s issue of the ... takes an in-depth look at various causes and consequences associated ... drug spending, which has generated significant public outrage and ... Laura E. Happe , PharmD, MPH. --> ... PharmD, MPH. --> In 2014 prescription drug ...
Breaking Medicine Technology: