Revisiting the basis for US ballast water regulations

The transport and release of invasive organisms in ballast water has harmed ecosystems, economic activities and human health. Current US ballast water regulations intended to minimize the discharge of such organisms are based on results reported by a scientific advisory committee in 2011. Using the same methods, we re-analyzed the data evaluated by the committee as well as new data. We find that the committee's analysis was flawed, and that some treatment systems can meet limits that are 10 times (for zooplankton) or 1000 times (for phytoplankton) more stringent than the committee reported. These findings suggest that US ballast water standards, and similar standards in a recently ratified international agreement, should be re-evaluated.