Mercury concentrations low in Main Station Farm soil following winter flooding

University of Nevada, Reno’s agriculture programs serve Nevada

Mercury concentrations low in Main Station Farm soil following winter flooding

University of Nevada, Reno’s agriculture programs serve Nevada

Soil samples taken from the University of Nevada, Reno's Main Station Farm in Reno show that mercury concentrations are low, and pose no threat to plants, animals or humans.

"When we read reports of higher levels of mercury along Steamboat Creek we wanted to be sure our land was not affected," said Bill Payne, dean of the College of Agriculture, Biotechnology and Natural Resources. "Sampling soil for a variety of reasons is one of the many things our scientists do on a regular basis, and we have one of the world's foremost experts on mercury in the environment, Mae Gustin. It just made sense for us to determine for ourselves what the effects the flooding might have had, and whether current mercury levels had any implications for plant and animal products from Main Station."

The 850-acre farm is east of South McCarran Boulevard at the end of Mill Street. While Steamboat Creek is a primary source of mercury in the Truckee River, the creek is near the east boundary of the farm. When Truckee River flooding occurs, the water that inundates the low levels of the farm is clean water coming upstream from the Truckee River that flows west to east across the farm.

"The primary pathway by which mercury enters plants is the atmosphere, and soil concentrations are not of concern, so there is no risk from mercury associated with growing vegetation and organisms at the farm," Mae Gustin, professor of biogeochemistry in the Department of Natural Resources and Environmental Science, said in her report following the study.

The Main Station Farm houses a number of projects related to dryland agriculture, soil, farm animal research and crop research, as well as the Wolf Pack Meats operation. The Desert Farming Initiative's hoop houses along Clean Water Way on the Farm provide vegetable to their Farm Stand and to St. Vincent's for their Meals on Wheels Program.

"Residents expressed concern about the mercury levels found in Steamboat Creek after the January flooding," Payne said. "We wanted them to have confidence that our activities and farm products are safe and were not adversely affected by the flooding. We also wanted to bring our research expertise to bear on something of local interest and to provide practical information to a concerned community."

Gustin enlisted several of her students to assist with the mercury soil study. They plotted 26 points across the 1,000-acre farm and two on the east side of the connector road in the Steamboat Creek area and took core samples and analyzed samples from different depths at each location.

The average concentration of all samples taken on the Main Station Farm was 0.167 parts per million, with the lowest at 0.038 and the highest at 1.399. The concentration considered as background in soils is less than 0.1 parts per million. Concentrations of concern for humans are 9.4 ppm, and 2.0 ppm is considered to be of concern for organisms living directly in the sediment. Of the soil samples taken at the two sites along Steamboat Creek one showed the highest average concentration at 1.556 ppm. The mercury in the creek dates back to the Comstock mining era and has been transported down Steamboat Creek from Washoe Lake for more than 150 years.

A subsequent analysis of the Main Station plot sample distribution by a student in a wetlands ecology class found the numbers suggest that mercury content within the sample cores close to Steamboat Creek were influenced by the mercury content in the water, with slightly higher levels closer to and along the edge of the creek.

"While it made sense to us, as scientists, that the flooding had little, if any, effect on soil concentrations of mercury, we didn't want to just make assumptions, especially with the history of Truckee River flooding," Chris Pritsos, Director of the Nevada Agricultural Experiment Station, of which the Main Station Farm is a part, said. "We wanted to validate it, and now we have data to support it. It's nice to have the hard numbers, with protocols and controls in place for the study and to be confident there is no concern for mercury affecting our animals, our research or our plants."

Main Station Farm Products
The Main Station Field Lab serves as a research facility for agriculture, hydrology, and meteorology, and serves the needs of agriculture students, researchers and faculty in a number of disciplines across the University. It is also used for Cooperative Extension activities. Acquired and developed in 1956, the farm is home to herds of cattle and sheep and showcases science and education in the areas of cattle health and performance, control and eradication of noxious weeds, meat science, dairy science, alternative agriculture, improved pastures, horticulture, and air, soil and water quality.

Produce grown on the farm by the University's Desert Farming Initiative is sold at the farm and at the University's Wolf Shop convenience store in the Student Union. Vegetables are also provided, through a partnership with the Catholic Charities of Northern Nevada, to their St. Vincent's poverty programs and Meals on Wheels.

Wolf Pack Meats, in operation since 1967 at the Main Station Farm, is a meat processing plant that specializes in student and professor interactions and educational opportunities. Students are able to get first-hand experience in meat production, retail distribution and packaging. Wolf Pack Meats is a USDA inspected facility that processes all of its products on site and is open to the public for retail sales. Along with the Nevada Agricultural Experiment Station, the Main Station Farm is used by the College of Agriculture, Biotechnology and Natural Resources and the University of Nevada Cooperative Extension in independent and collaborative research, education and outreach programs.

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