Navigation Links
Chloride found at levels that can harm aquatic life in urban streams of the Northern US
Date:9/16/2009

Levels of chloride, a component of salt, are elevated in many urban streams and groundwater across the northern U.S., according to a new government study.

Chloride levels above the recommended federal criteria set to protect aquatic life were found in more than 40 percent of urban streams tested. The study was released today by the U.S. Geological Survey (USGS). Elevated chloride can inhibit plant growth, impair reproduction, and reduce the diversity of organisms in streams.

The effect of chloride on drinking-water wells was lower. Scientists found chloride levels greater than federal standards set for human consumption in fewer than 2 percent of drinking-water wells sampled in the USGS study.

Use of salt for deicing roads and parking lots in the winter is a major source of chloride. Other sources include wastewater treatment, septic systems, and farming operations.

"Safe transportation is a top priority of state and local officials when they use road salt. And clearly salt is an effective deicer that prevents accidents, saves lives, and reduces property losses," said Matthew C. Larsen, USGS Associate Director for Water. "These findings are not surprising, but rather remind us of the unintended consequences that salt use for deicing may have on our waters. Transportation officials continue to implement innovative alternatives that reduce salt use without compromising safety."

This comprehensive study examines chloride concentrations in the northern U.S. covering parts of 19 States, including 1,329 wells and 100 streams.

Selected Highlights

Land use matters

Chloride yields (the amount of chloride delivered per square mile of drainage area) were substantially higher in cities than in farmlands and forests. Urban streams carried 88 tons of chloride per square mile of drainage area. Forest streams carried about 6 tons of chloride per square mile.

Only 4 percent of the streams in agricultural areas had chloride levels that exceeded the recommended federal criteria set to protect aquatic life (compared to more than 40 percent of urban streams). Overall, 15 percent of all streams had chloride levels exceeding the criteria.

Chloride concentrations in shallow groundwater (not used for drinking) were 16 times greater in urban areas than in forests, and 4 times greater in urban areas than in agricultural areas.

Highest levels in streams in the winter

In urban streams, the highest levels of chloride (as great as 4,000 parts per million, which is about 20 times higher than the recommended federal criteria) were measured during winter months when salt and other chemicals are used for deicing.

Increases over time

Increases in chloride levels in streams during the last two decades are consistent with overall increases in salt use in the U.S. for deicing.

Increasing chloride yields are linked to the expansion of road networks and parking lots that require deicing, increases in the number of septic systems, increases in wastewater discharge, and increases in saline groundwater from landfills.

Sources can vary locally

Chloride in ground and surface waters comes from many sources including the use and storage of salt for deicing roads, septic systems, wastewater treatment facilities, water softening, animal waste, fertilizers, discharge from landfills, natural sources of salt and brine in geologic deposits, and from natural and human sources in precipitation.


'/>"/>

Contact: John Mullaney
jmullane@usgs.gov
860-291-6760
United States Geological Survey
Source:Eurekalert

Related biology news :

1. Exotic timber plantations found to use more than twice the water of native forests
2. Anticancer compound found in American mayapple
3. Shifting baselines confound river restoration
4. NTU and Temasek Foundation transfer technology knowhow to Chinas quake-prone regions
5. Newly found DNA catalysts cleave DNA with water molecule
6. Essential nutrient found in eggs may help lower risk of neural tube defects
7. Little-known protein found to be key player
8. 121 breeding tigers estimated to be found in Nepal
9. Possible drug target found for one of the most aggressive breast cancers
10. Will IVF work for a particular patient? The answer may be found in her blood
11. UTSA wins San Antonio Area Foundation grant to further chlamydia research
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/27/2017)... N.Y. , March 27, 2017  Catholic ... Information and Management Systems Society (HIMSS) Analytics for ... EMR Adoption Model sm . In addition, CHS ... of U.S. hospitals using an electronic medical record ... for its high level of EMR usage in ...
(Date:3/24/2017)... Research and Markets has announced the addition of the ... Industry Forecast to 2025" report to their offering. ... The Global Biometric Vehicle Access ... 15.1% over the next decade to reach approximately $1,580 million by ... and forecasts for all the given segments on global as well ...
(Date:3/23/2017)... Mar. 23, 2017 Research and Markets has ... Analysis & Trends - Industry Forecast to 2025" report to ... ... a CAGR of around 8.8% over the next decade to reach ... analyzes the market estimates and forecasts for all the given segments ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... (PRWEB) , ... October 12, 2017 , ... ... for two-dimensional representations of a complex biological network, a depiction of a system ... big mess,” said Dmitry Korkin, PhD, associate professor of computer science at Worcester ...
(Date:10/12/2017)... ... October 12, 2017 , ... ... a United States multicenter, prospective clinical study that demonstrates the accuracy of ... capable of identifying clinically significant acute bacterial and viral respiratory tract infections ...
(Date:10/12/2017)... ... October 12, 2017 , ... ... the first-ever genomics analysis platform specifically designed for life science researchers to ... of pioneering researcher Rosalind Franklin, who made a major contribution to the ...
(Date:10/11/2017)... ... ... a basic first aid supply for any work environment, but most personal eye wash can ... a dangerous substance enters both eyes? It’s one less decision, and likely quicker response time ... , “Whether its dirt and debris, or an acid or alkali, getting anything in your ...
Breaking Biology Technology: