The people need electricity. What is the alternative? Use what we have or be in the dark.
Yes it's not an easy issue to solve but the world needs to move away from coal. Methylmercury pollution in the environment throughout the world is primarily from burning coal for power generation. Many people that consume large amounts of fish such as mahi mahi, tuna, sea bass, grouper, etc (those fish high on the food chain) all have elevated levels of methylmercury in their bodies. It tends not to be an issue for adults as their nervous systems are fully developed but it's a really bad idea for children to consume fish that are high on the food chain due to the biogmagnification of methylmercury in their tissues. If you're going to eat fish, sardines are a good choice.
Here's a link regarding the consumption of fish
here. A link regarding the health effects of methylmercury is
here.
There are numerous instances in the US of water from fly ash leaching into the ground and contaminating groundwater. It's a huge environmental problem. There are uses for fly ash as noted in a comment above but it's a tiny fraction of the amount that is produced.
Scroll down to ecology on this wikipedia
here for information about groundwater and other pollution.
I drove out to Pedernales 4 months ago and saw the wind farms the country has out there. The country has some excellent wind resources both onshore and offshore. The arid and unpopulated area west of Barahona would be perfect for a large solar installation. Battery storage technology is getting close. In the meantime, unless the Dom Rep can switch to natural gas, it looks like they are stuck with coal generation for the time being.
On a note you might find interesting, the Mad Hatter in Lewis Carroll's Alice in Wonderland has a quote, "twinkle twinkle little bat, how I wonder what you're at". It's a crazy little saying. Hatters in the old days used mercury to stiffen the brim and some suffered mercury poisoning and showed neurological problems (madness)
Again, the world needs to move away from coal for energy production.