Environ. Sci. Technol. 2003, 37, 659-660
Response to Comment on “Trace Metal Levels in Uncontaminated Groundwater of a Coastal Watershed: Importance of Colloidal Forms” We thank Buesseler et al. (1) for their interest in our paper on trace metal concentrations measured in groundwater of a coastal watershed in Long Island, NY (2). We also welcome the opportunity to respond to their comments. Buesseler et al. (1) raise several issues regarding our colloidal metal measurements that we would like to clarify. The first issue raised by Buesseler et al. (1) is the possibility of the artificial formation of colloids by changing the redox conditions of the groundwater. We were aware that exposure of reduced groundwater to the atmosphere could precipitate redox-sensitive elements such as Mn. For that reason, we limited our sample collections to wells located in the shallow unconfined upper glacial aquifer on eastern Long Island with relatively high levels of dissolved oxygen. Furthermore, levels of dissolved Mn in the groundwater sampled during our study were
