GardenBanter.co.uk - View Single Post - Plants that absorb harmful elements/toxins?

Phred · 12-08-2006, 11:46 AM posted to sci.bio.botany

In article , wrote:
On 11 Aug 2006 09:52:02 -0700, "Jeff" wrote:
I'm looking to compile a list of known seeds that will grow plants that
are able to absorb significant amounts of chemicals, pesticides, and
other well known harmful materials.

Could anyone give me pointers/URL's that would help in my research?
The environment where these plants will grow is central Massachusetts,
and yes, the plants need to be legal. ;-)

Several years ago, and way too many brain cells ago, I attended a
seminar on bioremediation by plants of mercury polluted soil.

From what I recall: A gene for mercury reactions in bacteria was identified.
Somehow, this was linked to mercury filling amalgams... [...]

Anyway, the most toxic form of mercury is not the elemental form, but
the states, such as mercury oxides and organic forms such as methyl
mercury.

The gene involved was introduced into a plant... I believe it was a
marsh plant... that grew in wet soil with non-elemental mercury
contamination. The plant was able to take the combined mercury toxins
in the soil, convert them into elemental mercury, and release the
elemental mercury as vapor into the atmosphere.

So... the question is: was this a good idea or not?

I've always understood mercury vapour to be pretty nasty stuff.

Quoting from http://www.minerals.csiro.au/safety/mercury.htm

Properties and Hazards
Liquid mercury produces enough vapour at room temperatures to poison
people who inhale the vapour for a period of time. At 20°C, the
equilibrium concentration of mercury vapour is about 150 times the
Threshold Limit Value for humans (which is 0.1 mg/m3, and is the
maximum atmospheric concentration for a normal working week).

It is very difficult to pour mercury without splashing or spilling.
Falling drops break into small droplets, many of which are too small
to be seen with the naked eye. Such small droplets will not
agglomerate, so that decontamination of an area where mercury has been
spilt is extremely difficult.

The vapour pressure of mercury increases rapidly with temperature,
that at 100°C being 200 times that at 20°C. As a consequence, ovens,
electric radiators, motors, and other warm or hot apparatus greatly
increase the mercury vapour concentration if droplets are left on or
near such equipment. A typically dangerous situation exists when a
mercury thermometer breaks in a heating oven, the design of which
usually makes decontamination very difficult. Dial thermometers with
stems must be used to monitor oven temperatures.

Mercury can be absorbed through the skin, as well as by inhalation.
There is no single diagnostic test for mercury poisoning, and extreme
care in the handling of the substance is essential.
/quoting

Cheers, Phred.

--
LID