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Environment: Pesticide pollution rising in urban streams


About half the nation’s streams are polluted by pesticides at a level of concern for aquatic life.

90 percent of urban streams show signs of contamination

Staff Report

FRISCO — A huge number of rivers and streams around the country are still polluted with pesticides that can kill bugs and other aquatic organisms at the base of the food chain.

Streams in agricultural areas are polluted at about the same level as they were 1990s, but pesticide pollution is increasing in urban streams, according to a U.S. Geological Survey study spanning about 20 years. Continue reading

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Study finds serious pollution in seabottom sediments of Guánica Bay, Puerto Rico


Trouble at the bottom of the Caribbean, as researchers document high concentrations of toxics in sediments.

Toxins may be harming coral reef ecosystems

By Summit Voice

FRISCO — Standing along the shore of Guánica Bay, Puerto Rico, the dazzling aquamarine Caribbean waters look normal. But deep below the surface, there may be trouble brewing, according to researchers with the National Oceanic and Atmospheric Administration.

Pollutants measured in the sediments of the bay are among the highest ever measured by NOAA’s National Status & Trends, a nationwide contaminant monitoring program that began in 1986. The pollutants include PCBs, chlordane, chromium and nickel, according to the new NOAA study. Continue reading

Environment: Exposure to herbicides makes amphibians more susceptible to chytrid fungus


Amphibians are in big trouble, and exposure to environmental pollution is a least partly to blame.

As of December 2012, there were 29 amphibian species classified as endangered or threatened and 5 species waiting to be listed. Overall frog and salamander numbers are declining and the cause, or causes, have not been determined ~ U.S. Fish and Wildlife Service

FRISCO — Early life exposure to the herbicide atrazine makes frogs much more susceptible to the chytrid fungus that has been implicated a global wave of amphibian die-offs.

Experiments by scientists at the university of South Florida showed that a six-day exposure to environmentally relevant concentrations of the most common herbicides in the world increased frog mortality 46 days after the atrazine exposure, but only when frogs were challenged with the chytrid fungus. This increase in mortality was driven by a reduction in the frogs’ tolerance of the infection.

Other research results have also suggested that exposure to pesticides suppresses the immune response in a variety of species, making them more susceptible to fungal infections and parasitic organisms. More information on the impact of environmental contaminants to amphibians is available at this USFWS web page. Continue reading

Environment: Study suggests diesel fumes may prevent honey bees from finding flowers


A Colorado bumblebee searches wild fireweed for pollen or nectar. bberwyn photo.

Reactive exhaust gases change or destroy odor profiles of flowers

By Summit Voice

FRISCO — Researchers tracking the decline of honey bees have discovered another clue, as a new study suggesta that diesel exhaust fumes may hinder the insects from finding flowers.

Bees use floral odors to help locate, identify and recognize the flowers from which they forage, but diesel fumes are highly reactive and can change the profile of floral smells, according to University of Southhampton researchers Dr. Tracey Newman and Professor Guy Poppy.

For the study (published Oct. 3 in Scientific Reports), the scientists mixed eight chemicals found in the odor of oil rapeseed flowers with clean air, and with air containing diesel exhaust. Six of the eight chemicals reduced (in volume) when mixed with the diesel exhaust air and two of them disappeared completely within a minute. The odour that was mixed with the clean air was unaffected. Continue reading

Study eyes selenium impacts to honey bees


Bees gather on wildflowers in Breckenridge, Colorado.

Exposure can lead to mortality, California researchers say

By Summit Voice

FRISCO — Along with pesticides, heavy metals may also be contributing to the decline of honey bees in some regions, according to entomologists at the University of California, Riverside.

Their research found that four main forms of selenium found in plants cause mortality and delays in development in the honey bee. Study results appear in the Oct. 2013 issue of the journal Environmental Toxicology and Chemistry.

“Metal pollutants like selenium contaminate soil, water, can be accumulated in plants, and can even be atmospherically deposited on the hive itself,” said Kristen Hladun, the lead author of the study and a postdoctoral entomologist. “Our study examined the toxic effects of selenium at multiple life stages of the honey bee in order to mimic the chronic exposure this insect may face when foraging in a contaminated area.” Continue reading

Historic Alpine glacier decline linked with soot

Study shows pollution melted glaciers even as temperatures cooled


Atmospheric pollution in the form of soot from fossil fuel combustion, apparently caused a rapid retreat of Alpine glacers even as regional temperatures cooled at the start of the Industrial age. Photo courtesy NASA Earth Observatory.

By Summit Voice

FRISCO — Matching climate records with ice core samples, scientists say the rapid retreat of Alpine Glaciers in Europe at the end of the Little Ice Age was probably linked with the sudden accumulation of soot particles associated with the beginning of the industrial Age.

Soot from industrial sources and even from wildfires has recently been implicated in the darkening of the Greenland ice sheet, leading to increased surface melt.

The new study helps resolve what had been a puzzle, as the sudden glacier decline coincided with a period of cooling regional temperatures. Between 1860 and 1930, temperatures in Europe cooled by nearly two degrees, yet at the same time, any large valley glaciers retreated by an average of about 0.6 miles (1kilometer).

“Something was missing from the equation,” said lead author Tom Painter, a snow and ice scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California. The study was published Sept. 2 in the Proceedings of the National Academy of Sciences. Continue reading

Environment: Frogs up and down the Sierra Nevada are tainted with pesticides from the Central Valley


USGS sampling found that Pacific chorus frogs in many remote Sierra Nevada locations are contaminated by pesticides and fungicides used in agricultural production in California’s Central Valley. Photo courtesy USGS.

Study even finds trace remnants of DDT, banned 40 years ago

By Summit Voice

FRISCO — Frogs in remote Sierra Nevada backcountry ponds are contaminated with traces of pesticides, including a byproduct of DDT, which was banned more than 40 years ago, showing how long some pollutants can persist in the environment.

The chemicals are heavily used in California’s Central Valley, one of the most productive agricultural regions in the world, and transported via wind, dust and precipitation to the High Sierra. Continue reading


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