Hello Victoria, 1) ...

Hello Victoria,

1) Boreholes can have different purposes and thereof may depend their ability to impact or not the environment. Regarding impact on groundwater, I believe the most common sort of negative impact will arise when a borehole connects different aquifers transferring water between them. Different water compositions may lead to direct contamination in case one of them is contaminated on one hand. ON the other hand, even if the water is just different but not contaminated, it may destabilize the solid phase in the other aquifer, leading to adsorbed contaminant liberation. This is also a typical phenomenon with injection wells.

2) There is an ongoing discussion about man made earthquakes due to the practice of fracking. Fracking is often used in deeper wells in order to make them more permeable. A fluid is injected with great pressure with the purpose of fracturing the rock. This technique is used in water as well as oil wells. Besides making the rock less "solid", the technique greatly increases pore pressure leading to the "lubrication" of the rock, that has just become less competent.

Wells that serve the purpose of injection contribute to a rise in pore pressure and might thus depending on their setting and depth contribute more or less to an increase of the likelihood of an earthquake.

On this page from the United States Geological Survey you will find a report on the matter

http://earthquake.usgs.gov/research/induced/srl.php

3) Yes, different countries have different regulations not just for boreholes in general but depending on the purpose they are made for: groundwater abstraction, injection, CO2 storage, wastewater injection, heat storage/retrieval, investigation, monitoring, Oil/Gas...

Regards

Francisco