I always like to hear all about how people scrub the dangerous fossil fuel waste, mercury, from coal exhaust and then pretend it goes away.
Um... Really?
Whatever. There are other kinds of waste besides dangerous fossil fuel waste. Even if there were no such thing as dangerous fossil fuel waste, in some cases naturally occurring toxins would still be present. In many parts of the world, Bangladesh is the most notable, drinking water is contaminated by arsenic that leaches from natural deposits of arsenic. To some extent - in Bangladesh - the problem has a human element. India consumes most of the water in the Ganges before it gets to Bangladesh - and so the Bengalis have been pumping fossil ground water out of the ground. Because the rocks beneath Bangladesh contain significant arsenic ore, this water is contaminated.
As a result, many Bengalis suffer from arsenic poisoning, a problem about which the world couldn't care less.
The Indian approach to dealing with this issue is to build - why does this sound familiar? - to build a huge fence around Bangladesh to keep any water refugees out.
Good idea, I guess.
Another place where arsenic contamination is endemic is the American West, where arsenic is found in the water from things like old silver, copper and gold mine tailings and from percolating through unmined rocks.
If you live in a rich country where you can afford things like water treatment problems you can actually but a kind of purification system that quantitatively removes arsenic. Aren't you in luck?
Of course, arsenic can't be destroyed, at least without neutrons - and there will never be enough neutrons on earth to make much of an impact in any case - because as most people know, it's an element. So where does the arsenic go when it's removed? Well, folks, it stays right in the removal device. And what happens to the removal device when it's all filled up with arsenic? Why it goes to a landfill. And what happens in the landfill. An article in the journal Science of the Total Environment
Sci. Tot. Envir. 389, Issue 1, 188-194 (2008) addresses this issue.
An excerpt from the article:
The biogeochemical cycle of naturally-occurring As in the terrestrial as well as aquatic environment has been extensively studied in recent years due to increased awareness of As contamination and toxicity (Nickson et al., 1998; Islam et al., 2004). Microbial activities are ubiquitous in the geochemical environment, and they play an essential role in the As biogeochemical cycle by transforming As to various species that display different mobility and toxicity (Ahmann et al., 1994; Oremland and Stolz, 2003; Kirk et al., 2004). Landfill leachate is reported to have a bacterial content of 108 to 109 cells/ml and contains a broad variety of microorganisms (Ludvigsen et al., 1999; Christensen et al., 2000). The iron- and sulfate-reducing bacteria are the most frequently observed microorganisms in landfill leachate (Ludvigsen et al., 1999), and represent a sizable fraction of the microbial population...
...The spent adsorbents were collected from pilot-scale filtration
systems tested for As(V) removal in groundwater at Hopewell, New Jersey, as shown in our previous report (Jing et al., 2005). The adsorption filters including GFH (US Filter, Iowa), GFO (Apyron Technologies, Georgia), TiO2 (Hydroglobe, New Jersey), AA (Alcan, Ohio), and MAA (Alcan, Ohio), respectively, were operated in parallel at the wellhead. The As content in the spent GFH, GFO, TiO2, AA and MAA was 2420, 5660, 3554, 226, and 443 mg/kg, respectively (Jing et al., 2005)...
During the incubation test, As was released from the spent adsorbents to the culture solution (Fig. 2a). Less than 1% A swas leached out for each adsorbent in the first 10days, corresponding to the initial rapidpedecrease (Fig. 1). This observation indicated...
...that the first 10days might be a lag phase for microorganism growth. The amount of As released from TiO2 to the solution increased to 38% of the total As at 40days and began to decrease thereafter. Approximately 4% of the arsenic was released from the GFO after 27 days and remained at this level until 40days before declining. The amount of arsenic released from TiO2 and GFO was much higher than from the other three spent adsorbents due to the high As contents in these two adsorbents. The high percentage of As release in the TiO2 system coincided with the dissolution of the adsorbent (Fig. 2b). After 15 days of incubation, the percentage of soluble TiO2 increased significantly and reached about 5.7% at 27days...
To make a long story short, the arsenic removed from the ground water - via landfills - goes back into the ground water, concentrated.
And while we're on the subject of happy talk, one hears about these wonderful mercury scrubbers on coal fired powered plants. The same people who hold forth - in an extremely confused fashion by the way - about the half life of materials in used nuclear fuel, in general neither know nor care that the half-life of mercury is infinite - it will remain toxic for eternity for as long as humanity lives.
And where, exactly, do they dump this scrubbed mercury? Inquiring minds want to know.