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The new monitoring wells will be sampled initially a minimum of 24 hours following well development. The wells will be sampled at least three more times prior to dredge material being placed in the site. The sampling events will be spaced by at least 2-3 weeks in time. Prior to collecting samples, the water level will be measured using an electric sounder, and at least four casing volumes of groundwater will be purged from each well using a submersible pump. During purging, field water-quality parameters (pH, temperature, dissolved oxygen, EC, and turbidity) will be measured. Groundwater samples will be collected in laboratory-prepared containers, placed in ice-cooled chests, and delivered to the laboratory under chain-of-custody procedures. Groundwater samples will be submitted for analysis in accordance with the SAP. The RWQCB identified four metals (Comment 37) as constituents of concern (COCs): lead, barium, copper, and zinc. These metals, as well as other inorganic chemicals,will be analyzed as summarized below. • Dissolved lead, barium, copper, and zinc using EPA method 6010. • Inorganic constituents including chloride, sulfate, nitrate as nitrogen, TDS, potassium, bicarbonate, carbonate, sodium, calcium, magnesium, dissolved iron, and dissolved manganese using various EPA methods. Quality assurance/quality control samples will also be collected and submitted to the laboratory for potential analysis, including one or more equipment blanks, one field blank per day, and one trip blank per sample shipment. All groundwater samples will be placed in laboratory- prepared sample containers and labeled with a unique sample control number, date of collection, and project number. A sample control log will be prepared to identify the sample control numbers with the appropriate well number, depth, and other pertinent criteria. The deliverable for this task will be lithologic logs and well completion diagrams for the monitoring wells and tables of the analytical data from groundwater samples. TASK 4-EVALUATE SITE ATTENUATION POTENTIAL This task will provide the basis for identifying the attenuation potential of the DPS soils and determining whether the dredge material can be viewed as a designated waste. The soil that comprises the DPS will have a certain capacity for attenuation of metals that may leach from the dredged materials. The potential of the soil for attenuation is based on a number of physical and chemical characteristics of the soil including the cation exchange capacity, total IA\MARKET\PROPOSAL\2000 Props\6988-POS\Amended work plan.doc 4