Farm-grown fish are an important source of food with significant and worldwide societal and economic benefits, but the fish that come from these recirculating systems can have unpleasant tastes and odors. To clean contaminated water for farmed fish, drinking and other uses, scientists are now turning to an unlikely source -- the mucilage or inner "guts" of cacti.

Low Emissions Zones have their place in cleaning up the UK's worst air pollution hotspots, writes Richard Howard. But we also need to adopt fiscal measures to encourage a shift away from diesel vehicles, at once delivering cleaner air, increased tax revenues, and lower carbon emissions.

If we are to clean up air pollution in London and the rest of the UK, then Government needs to recognise that diesel is the primary cause of the problem, and to promote a shift away from diesel to alternatives.

There is an air pollution crisis taking place in London and many of the UK's other major cities.

Most people know that properly inflated tires can improve a vehicle’s fuel efficiency, but did you know that properly maintained roadways can improve fuel efficiency across an entire pavement network?

The world's workshop -- China -- surpassed the United States as the largest emitter of greenhouse gases on Earth in 2007. But if you consider that nearly all of the products that China produces, from iPhones to tee-shirts, are exported to the rest of the world, the picture looks very different.

Volkswagen is still struggling to move past the emissions-software scandal that has plagued its reputation for the better part of a year. Ever since the news officially broke that an array of its diesel passenger cars were outfitted with deceptive software, VW’s reputation has been pretty much at bottom ratings.

It’s not like the company hasn’t tried to regain public trust: To disgruntled consumers who bought one of the affected cars, it’s offered a combo of Visa cards and credit at dealerships. To dealers stuck with stock frozen by the publicity, the company offered to buy back used vehicles at full price.  And in response to hundreds of class-action suits coming up on the horizon, the company recently suggested that it may be willing to buy back those vehicles that can’t be fixed. Fixing, VW lawyer Robert Giuffra explained in court in January, requires coming up with new software, and that may still be a long way off — too long for some earlier vehicles caught in the debacle.

In the concrete jungle at the core of a city, carbon dioxide (CO2) emissions are dominated by the fossil fuels burned by the dense concentrations of cars and buildings. Boston University researchers now have shown, however, that in metropolitan areas surrounding the city core, plant roots and decomposing organic material in soil give off enough CO2 , in a process termed "soil respiration", to make an unexpectedly great contribution to total emissions.

As renewable energy sources goes, solar rays have historically hogged the limelight. 

But two Virginia Tech researchers have stolen the spotlight from the sun by discovering a way to maximize the amount of electricity that can be generated from the wastewater we flush down the toilet. 

The Japanese were kept in the dark from the start of the Fukushima disaster about high radiation levels and their dangers to health, writes Linda Pentz Gunter. In order to proclaim the Fukushima area 'safe', the Government increased exposure limits to twenty times the international norm. Soon, many Fukushima refugees will be forced to return home to endure damaging levels of radiation.

Once you enter a radiation controlled area, you aren’t supposed to drink water, let alone eat anything. The idea that somebody is living in a place like that is unimaginable.

As such, one might have expected a recent presentation he gave in the UK within the hallowed halls of the House of Commons, to have focused on Japan's capacity to replace the electricity once generated by its now mainly shuttered nuclear power plants, with renewable energy.

USGS scientists have detected toxins known as microcystins produced by various forms of algae in 39 percent of the small streams assessed throughout the southeastern United States. Their recent study looked at 75 streams in portions of Alabama, Georgia, North Carolina, South Carolina and Virginia.

Adults with long-term exposure to ozone (O3) face an increased risk of dying from respiratory and cardiovascular diseases, a study  “Long-Term Ozone Exposure and Mortality in a Large Prospective Study” published online ahead of print in the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine suggests.

Using data from a large U.S. study begun in 1982, researchers found that every additional 10 parts per billion (ppb) in long-term ozone exposure increased the risk of dying by:

• 12 percent from lung disease
• 3 percent from cardiovascular disease
• 2 percent from all causes

Researchers said the increased risk of death was highest for diabetes (16 percent), followed by dysrhythmias, heart failure and cardiac arrest (15 percent) and by COPD (14 percent).