Impacts of volcanic ash

Here's a nice little video clip of the impacts of volcanic ash, it focuses mostly on the effects on aircraft.
Effects of volcanic ash

How does volcanic ash form?
What other impacts are there?

World to end in 2036?!

Or maybe not, but either way scientists predict a close call with Apophis asteroid. Apophis is due to pass within 30,000km of Earth on Friday April 13 2029 (unlucky for some?!), and although the Earths gravity will alter its path it should pass on into space harmlessly (to us at least!). However.......
Asteroid closes on Earth

United Nations report that mining has lead to an increase in mercury emissions

Increase in Mercury emissions

For the full story, follow the link above, but for a snapshot - read on.

Basically Mercury is naturally forming element (chemical symbol Hg), it forms the mineral Cinnabar. And has the distinction of being the only metal that is liquid at room temperature and evaporates easily. It is extremely rare, being found in only a few places around the world, although these deposits tend to be heavy concentrations. It is used in flourescent bulbs, and has application in medicine and laboratory work. Historically it was used in thermometers, although this practice was stopped some time ago.

Mercury can be released into the environment by a number of industrial processes; mining, metal and cement production and the burning of fossil fuels. Once emitted it persists in the environment for a long time and can spread long distances.

The World Health Organization (WHO) says: "Mercury is highly toxic to human health, posing a particular threat to the development of the (unborn) child and early in life.

"The inhalation of mercury vapour can produce harmful effects on the nervous, digestive and immune systems, lungs and kidneys, and may be fatal.

"The inorganic salts of mercury are corrosive to the skin, eyes and gastrointestinal tract, and may induce kidney toxicity if ingested."

Cinnabar (HgS)

Mercury (Hg) iquid at Room temperature