Human activities contribute to rise of dissolved solids in U.S. streams, finds study

Sponsored by


RESTON, VA, June 16, 2014 -- According to a new study by the U.S. Geological Survey (USGS), a variety of human activities has contributed to elevated concentrations of dissolved solids, a measure of the salt content in water, in many streams across the nation.

The study determined that in about 13 percent of U.S. streams, concentrations of dissolved solids likely exceed 500 mg/L, which is the Environmental Protection Agency's (EPA) secondary, non-enforceable drinking water standard. Many of these streams are found in a north-south oriented band stretching from west Texas to North Dakota.

Accordingly, widespread occurrences of moderate concentrations are found in streams extending in an arc from eastern Texas to northern Minnesota to eastern Ohio, and low concentrations are found in many states along the Atlantic coast and in the Pacific Northwest.

The total amount of dissolved solids delivered to all streams is about 270 million metric tons annually, of which about 71 percent comes from weathering of rocks and soil, 14 percent from application of road de-icers, 10 percent from activities on agricultural lands, and 5 percent from activities on urban lands.

"For years we have known that activities, such as road de-icing, irrigation and other activities in urban and agricultural lands, increase the dissolved solids concentrations above natural levels caused by rock weathering," said William Werkheiser, USGS associate director for water, "and now we have improved science-based information on the primary sources of dissolved-solids in the nation's streams."

All water naturally contains dissolved solids as a result of weathering processes in rocks and soils. Some amount of dissolved solids is necessary for agricultural, domestic and industrial water uses and for plant and animal growth, and many of the major ions are essential to life and provide vital nutritional functions. Elevated concentrations, however, can cause environmental and economic damages.

As such, an online, interactive decision support system provides easy access to the national-scale model describing how streams receive and transport dissolved solids from human sources and weathering of geologic materials. The decision support system can be used to evaluate combinations of reduction scenarios that target one or multiple sources and see the change in the amount of dissolved solids transported downstream waters.

The dissolved-solids model was developed by the USGS National Water-Quality Assessment Program, which provides information about water-quality conditions and how natural features and human activities affect those conditions. Information on modeling applications, data and documentation can be accessed online.

"This study applied statistical modeling to understand the sources and transport processes leading to dissolved-solids concentrations observed in field measurements at over 2,500 water-quality monitoring sites across the nation," said David Anning, USGS lead scientist for the study. "This new information was then used to estimate contributions from different dissolved-solids sources and the resulting concentrations in unmonitored streams, thereby providing a complete assessment of the nation's streams."

See also:

"U.S. stream quality degraded by flow modifications, contaminants, says report"

"USGS report examines status of groundwater quality"

###

Sponsored by

TODAY'S HEADLINES

WERF expands research to further examine wastewater as a resource

The Water Environment Research Foundation is expanding its research with new projects examining wastewater as a resource. Two of the projects seek to show that materials in wastewater can be commoditized. The third explores a new method to reduce phosphorus in wastewater.

CH2M HILL global water market president joins WFP's first annual Leadership Council

Water For People recently hosted its first annual Leadership Council. Greg McIntyre, CH2M HILL Global Water Market president and Leadership Council member, joined WFP CEO Ned Breslin, Board Chair Patrick McCann and other industry leaders to discuss opportunities as well as programmatic and operational challenges.

City of Toledo to adopt new biosolids recycling program to improve Lake Erie water quality

Synagro Technologies recently announced details of a five-year biosolids recycling program in the city of Toledo, Ohio, that will improve water quality in the Lake Erie watershed by reducing the use of commercial chemical fertilizer.

EPA announces first national regulations to safeguard coal ash disposal

The Environmental Protection Agency has announced the first national regulations to provide for the safe disposal of coal combustion residuals (coal ash) from coal-fired power plants. 

FOLLOW US ON SOCIAL MEDIA