More than 200 private drinking water wells have been contaminated by natural gas drilling activity in Pennsylvania since 2007, according to documents released late Thursday by the Pennsylvania Department of Environmental Protection. The DEP released a list of 243 well contamination complaints that led to investigations and, in most cases, some form of resolution. The number of complaints amounts to 2.8% of the 7,536 unconventional wells drilled since 2009. Between 2009 and 2010, during the land rush to the Marcellus, water complaints nearly doubled from 34 in 2009 to 61 in 2010, the record shows. About half drinking water wells were damaged by conventional drilling and half by unconventional, or horizontal, drilling, DEP Deputy Secretary for Oil and Gas Management Scott Perry said in a statement. Complaints declined 41% in 2011 to 36 contaminated wells and remained at that level until dropping again this year to 1.3% of the […]