Freshwater Is Getting Saltier, Threatening People and Wildlife

Freshwater Is Getting Saltier, Threatening People and Wildlife

SOURCE: Scientific American DATE: December 6, 2018 SNIP: Salts that de-ice roads, parking lots and sidewalks keep people safe in winter. But new research shows they are contributing to a sharp and widely rising problem across the U.S. At least a third of the rivers and streams in the country have gotten saltier in the past 25 years. And by 2100, more than half of them may contain at least 50 percent more salt than they used to. Increasing salinity will not just affect freshwater plants and animals but human lives as well—notably, by affecting drinking water. When Sujay Kaushal, a biogeochemist at the University of Maryland, College Park, who studies how salt invades freshwater sources, sampled the local water supply he found not just an elevated level of the sodium chloride, widely used in winter to de-ice outdoor surfaces, but plenty of other salts such as sodium bicarbonate and magnesium chloride. How people use the land is another important factor. “Today, the saltiest streams are in the northern Great Plains,” scientist John Olson at California State University, Monterey Bay says. “Salinity is naturally high, and mining and oil and gas extraction are releasing more salt by exposing new rock and pumping out saline groundwater.” In those places, he adds, it is not unusual to find streams that are about half as salty as ocean water. The largest predicted increases are in the arid Southwest, however. The combination of expanding agriculture and reduced rainfall there would require careful irrigation management, Olson says. In the Colorado River Basin, where several such projects are ongoing, the economic cost of salinization is...
DDT in Alaska meltwater poses cancer risk for people who eat lots of fish

DDT in Alaska meltwater poses cancer risk for people who eat lots of fish

SOURCE: University of Maine DATE: December 6, 2018 SNIP: Children in Alaska whose diet includes a lot of fish from rivers fed by the Eastern Alaska Mountain Range may have a long-term elevated risk for cancer because of insecticides — including DDT — in the meltwater. Even with low levels of organochlorine pollutants (OCPs) in glacial meltwater, the risk of cancer for youth and adults who rely on fish as a staple of their diet is above the Environmental Protection Agency’s threshold limit. As Alaskan glaciers melt in the warming climate, the gradual release of these OCPs may continue to elevate watershed concentrations above the current level. DDT was used as a pesticide for insect control in the U.S. until the EPA banned it in 1972. Hexachlorocyclohexane, commonly called Lindane, has not been produced in the U.S. since 1976, but it’s imported for insecticide use and is in prescription creams that combat lice and scabies. The OCPs deposited and stored near the surface of Jarvis Glacier in interior Alaska likely were transported there in the atmosphere — attached to snow and rain. In Asia, DDT is still used to try to prevent...
‘We’re sounding the alarm’: half of Canada’s chinook salmon endangered

‘We’re sounding the alarm’: half of Canada’s chinook salmon endangered

SOURCE: The Guardian DATE: December 5, 2018 SNIP: Half of Canada’s chinook salmon are endangered, with nearly all other populations in precarious decline, according to a new report, confirming fears that prospects for the species remain dire. The report by the Committee on the Status of Endangered Wildlife in Canada concluded that eight of the country’s 16 populations are considered endangered, four are threatened, one is of special concern and the health of two remain unknown. Only one population, which spawns on the Thompson river in British Columbia, is believed to be stable. Chinook salmon are also a critical source of food for the endangered south resident killer whale, which the federal government has spent millions of dollars attempting to...
Global warming threat to Scottish fish stocks

Global warming threat to Scottish fish stocks

SOURCE: Scottish Association for Marine Science DATE: October 31, 2017 SNIP: Cod, herring and haddock may vanish from Scotland’s west coast waters by the turn of the century because of global warming. Researchers at the Scottish Association for Marine Science (SAMS), near Oban, have predicted that by 2100 commercially important species could migrate out from this ecosystem, most likely to colder waters further north, in response to rising sea temperatures. The findings, published in the journal Scientific Reports, show that cod and herring off Scotland’s west coast are already nearing the edge of their temperature tolerance range. “Our results showed that warmer climate could jeopardise sustainable fishery management: rising temperature showed strong negative impact on cold water species such as grey seals, cod, haddock and herring, which all declined by 2100 under the worst case climate warming scenario. “Even under the best case climate change scenario, cod and herring stocks were predicted to collapse off Scotland’s west...
Rising carbon dioxide emissions pose ‘intoxication’ threat to world’s ocean fish

Rising carbon dioxide emissions pose ‘intoxication’ threat to world’s ocean fish

SOURCE: Science Daily DATE: January 20, 2016 SNIP: UNSW Australia researchers have found that carbon dioxide concentrations in seawater could reach levels high enough to make fish “intoxicated” and disoriented many decades earlier than previously thought, with serious implications for the world’s fisheries. The UNSW study, published in the journal Nature, is the first global analysis of the impact of rising carbon dioxide emissions from fossil fuels on natural variations in carbon dioxide concentrations in the world’s oceans. … “High concentrations of carbon dioxide cause fish to become intoxicated — a phenomenon known as hypercapnia. Essentially, the fish become lost at sea. The carbon dioxide affects their brains and they lose their sense of direction and ability to find their way home. They don’t even know where their predators are.” — Dr. Ben...