Braun Intertec collected and evaluated sediment, water, groundwater, elutriate, and consolidated soil samples to characterize proposed dredge materials for future marine terminal development. Sampling methods, locations, and analytical requirements followed a U.S. Army Corps of Engineers (USACE)-approved sampling and analysis plan (SAP).

Two distinct sampling areas were evaluated during the investigation. The first consisted of dry sediment and required only soil and groundwater sampling. The second area contained shallow surface water (generally less than 5 feet deep) and necessitated the collection of soil, groundwater, and elutriate samples. Elutriate was prepared using surficial sediments/submerged soil from the 0-10’ depth interval and corresponding surface water. Both areas were further subdivided into three stratigraphic depth intervals: 0-10’, 10-20’, and 20-45’ depth intervals to reflect the Site’s general subsurface profile. A marsh-buggy drilling rig was utilized to access saturated zones and facilitate sample collection across shallow surface water areas.

The Site was subdivided into 24 hexagonal grids to ensure representative sampling. Composite elutriate samples were collected to represent the entire Site to reduce sample volume and total project costs. All multi-media samples were submitted to an accredited laboratory for analysis. Quality assurance/quality control procedures outlined in the SAP included duplicate field samples and matrix-spike (MS)/matrix-spike duplicate (MSD) analyses. Required analytes included ammonia, various metals, total organic carbon, total petroleum hydrocarbons, volatile and semivolatile organic compounds, polychlorinated biphenyls (PCBs), cyanide, dioxins, furans, pesticides, hexavalent chromium, percent moisture, grain size, and tributyltin.
Braun Intertec evaluated field and laboratory data using the statistical approach defined in the SAP. U.S. Environmental Protection Agency (EPA) statistical software was used to calculate 95% upper confidence limits (UCLs) and assess homogeneity by area and depth interval, significantly reducing sampling requirements. Braun Intertec prepared summary reports documenting soil, groundwater, and elutriate analytical results in accordance with USACE requirements. Project deliverables were submitted to the City of Texas City and other designated entities on time and within budget.