Natural gas is regarded as a relatively clean source of energy but there is mounting evidence that it has a dirty side.

My colleague Jon Hurdle has reported on Wyoming water woes that have been linked to the booming gas industry. You can see his stories here and here.

In August U.S. government scientists reported that they had for the first time found chemical contaminants in drinking water wells near natural gas drilling operations, fueling concern that a gas-extraction technique is endangering the health of people who live close to drilling rigs.

The Environmental Protection Agency found chemicals that researchers say may cause illnesses including cancer, kidney failure, anemia and fertility problems in water from 11 of 39 wells tested around the Wyoming town of Pavillion in March and May this year.

On Monday, I reported that high concentrations of harmful compounds have been found in the air in a north Texas town that is in the heart of the region’s gas industry, according to a report released by an environmental consultancy.

The study by Wolf Eagle Environmental Engineers and Consultants found high concentrations of carcinogenic and neurotoxin compounds in the atmosphere at seven locations around the rural town of DISH, which is about 50 miles northwest of Dallas.

Carcinogens are linked to cancers while neurotoxins are toxins that act on nerve cells.

The report said the levels of several of the substances exceeded those that the Texas Commission on Environmental Quality (TCEQ) uses as benchmarks or triggers that could prompt it to investigate or take action. This does not mean that these levels are an immediate hazard but the town’s mayor Calvin Tillman told me that he would like to see the several compressor stations in the area shut down until people are reassured that they are not emitting toxins.

DISH is on the Barnett Shale, a large geological formation in north Texas that contains vast amounts of natural gas.

What do you think? Is natural gas a viable option in the quest for an energy source cleaner than coal, which emits about twice as much carbon dioxide? Or must the industry first clean up its own act?

(Photo: A worker at EnCana’s Frenchie Draw gas-drilling rig in central Wyoming guides sections of steel pipe into an 11,000-foot well on September 19, 2009. REUTERS/Jon Hurdle)

London's transport bosses are telling travellers on the tube system to beat the heat by carrying a bottle of water with them when they venture underground.

But how many of us are refilling our bottles with tap water rather than pouring money down the tube -- not to mention the cost of recycling the plastic bottles -- by buying a new bottle of water each day?

Cue the National Hydration Council whose eye-catching advertising campaign to encourage people to buy more "naturally sourced bottled water" -- on health grounds -- featured prominently on the underground network earlier this year.

The worrying thing for the bottled water lobby is not that people are doing what would appear to be the most sensible thing and refilling their bottles from the tap, but that Britons are replacing bottled water with sugary drinks instead.

We're told that sales of bottled water fell by 7 percent last year, with 71 percent of that decline the result of people buying sweet drinks instead. Good news for the soft drinks industry perhaps, but a worry for health officials.

Meanwhile, beneath the streets of London, the hot and flustered faces of fellow tube passengers shows just how dire it is on board the capital's underground trains when the mercury rises.

With a decent air-conditioning system on most lines a distant prospect, Transport for London (TfL) could show it cares by offering each of its cash-strapped passengers a free TfL water bottle and the opportunity to refill them at its stations.

Could a constant search of the Internet help protect the environment by picking up early hints about pollution or signs of climate change such as desertification, droughts or heatwaves?

A study issued on Thursday hints that it could.

A scuba diver in the South China Sea off Malaysia (above, picture by David Loh of Reuters News) might write a blog if corals looked damaged by ‘bleaching’ – algae that give reefs their colours can start to die off because of higher sea temperatures. It might just turn out that divers far away in Australia, the Caribbean or elsewhere were starting to notice the same thing — perhaps setting off alarm bells about global warming.

“The Internet has the possibility to link up anecdotes to see if there’s a pattern,” said Tim Daw of the University of East Anglia who was among the authors. All that would be needed is an automated trawl of the Internet to pick up the information.

Daw told me, for instance, that he’s from Scotland where villages in the northwest had suffered a population explosion of millipedes. ”People have had their houses overrun,” he said. No one knew why.

That sort of pest invasion might make it to a local online newspaper – the sort of snippet that might just fit a wider picture of environmental change, perhaps because of global warming.

Already, outbreaks of disease are tracked online by the Canadian-developed Global Public Health Intelligence Network (GPHIN), for instance, which picks up many early hints of medical emergencies.

So could an Internet search ever be smart enough to save the planet?