Assessing the degree of appropriate treatment of shipyard and drydock wastewater discharges and stormwater runoff

Shipyards´ and drydocks´ (SYDD) wastewater discharges and stormwater runoff are currently being regulated to control the concentrations of chemical constituents in the discharges/runoff. The regulatory approach typically being used is based on worst-case assessments of the potential impacts of chemical constituents in the discharge/runoff as it may impact aquatic life in the receiving water column and sediments. This worst-case-based regulatory approach can readily lead to significant over-regulation, where SYDD are required to spend more funds in treating wastewater discharges and stormwater runoff than are necessary to protect the designated beneficial uses of the receiving waters for the discharges. This paper presents an evaluation monitoring approach that will enable SYDD managers to work with regulatory agencies in assessing the appropriate degree of wastewater and stormwater treatment/management to protect designated beneficial uses of receiving waters without unnecessary expenditures. The focus of evaluation monitoring is on assessing the impacts of chemicals on aquatic life, and controlling these impacts in a technically valid, cost effective manner. This approach is significantly different from current regulatory approaches, which focus on chemical concentration control without regard to the aquatic chemistry/toxicology of the constituents of concern in wastewater discharges and stormwater runoff. Rather than measuring the concentrations of copper and then trying to extrapolate to aquatic life toxicity in the water column and sediments. Evaluation monitoring focuses on using aquatic life toxicity tests to determine if the receiving waters for the wastewater discharge/stormwater runoff are toxic. If toxicity is found, the constituents responsible are identified and, through forensic studies, their source is determined