These concurrent sampling efforts involved characterizing sediments proposed to be dredged from San Juan Harbor and excavated from the Rio Puerto Nuevo in San Juan, Puerto Rico. The main objective was to determine the suitability of dredged material for disposal in the San Juan ODMDS.
San Juan Harbor provides access to deep-draft vessel traffic using terminal facilities in San Juan. These port facilities handle most of the cargo for the island of Puerto Rico. Sediment samples were collected throughout the harbor using a vibracore. The Rio Puerto Nuevo is south of San Juan Harbor, and the outlet is in the southeast corner of the harbor. Several samples were collected using a Geoprobe coring device and were representative of the material to be excavated.
ANAMAR coordinated and directed the operations for this project and worked closely with the client and subcontractors to organize security issues, schedules, sample collection, preparation, delivery, and analyses. Samples from each project area and an offshore reference station (>500 feet) were analyzed for physical, chemical, and toxicological parameters.
This project is an example of ANAMAR achieving success where previous contractors did not. In San Juan Harbor, a previous contractor had failed to properly follow the project Work Quality Assurance Project Plan (WQAPP) that had been approved by EPA Region 2. The required minimum detection limits (MDLs) for numerous chemical parameters were not achieved and insufficient sediment was collected to perform bioassay analyses correctly. ANAMAR successfully performed all aspects of this project in an expedited manner to meet the demands of the project dredging schedule and prevent delays. All data were acceptable to EPA Region 2.
In Rio Puerto Nuevo, the dredge material had consistently failed toxicity tests during previous sampling events. Before designing the WQAPP, ANAMAR obtained and studied historical data from previous sampling events. It was discovered that the bioassay tests performed were not appropriate for the high amount of stiff clay that was present in the samples. ANAMAR identified a sediment acclimatization process that could be performed on this material before performing the bioassay tests. This process was approved by EPA. By using this test procedure, it was determined that the material would be suitable for offshore disposal, a significantly less expensive disposal method than other disposal options for the material. In addition, by performing these projects concurrently, ANAMAR saved USACE the cost of additional mobilization and offshore sampling.