Groundwater sampling from deep wells 

Deepwell sampling for sensitive compounds such as volatile solvents, gasses (methane, vinylchloride) or metals adsorbed to colloidal matter requires sampling equipment with accurate discharge rate control to avoid turbulence and the ability to maintain (back-) pressure on the water to avoid degassing. Shown a stainless steel - teflon bladder pump capable of sampling from depths up to 500 m (1500 ft).