Ann Arbor – Ann Arbor officials say they will work with Pall Corporation in an effort to fully discover the extent of one-four dioxane contamination in groundwater. City Council last night gave premilinary approval to a measure requiring a permit to drill a monitoring well anywhere in the city. The former Gelman Sciences company recently drilled such a well to try and determine the extent of the contamination plume. It did so without city knowledge. Mayor John Heiftja says it will work with the company and this measure will force Pall Life Sciences to inform and include the city in it's plans.