Conceptual Site Model identification of size, location, geology, lithology, hydrogeology, areas of concern, contaminants of concern, recognized environmental conditions, historic sampling locations and results, data gaps, risk assessments, potential exposure pathways, offsite concerns, etc.
Conceptual Site Model. 2 Based on the results of the Phase I ESA it is likely that VOCs and SVOCs associated with 3 mill operations and documented UST and AST releases have impacted the surface and 4 subsurface soils at the Site. Impact by VOCs and SVOCs may also exist in groundwater 5 throughout the subject property and surface water and sediment on the eastern part of the 7 into the subsurface. The Phase II ESA will evaluate extents of impact and assess the 8 subsurface conditions. Evaluation of structural debris during the Phase II ESA will also 9 identify if asbestos is present at the Site.
Conceptual Site Model. The existing draft ecological conceptual site model (CSM) presented in the RI Report was revised, as appropriate, and is available as Figure 1. The CSM presents potential chemical sources, release mechanisms, receptors, and exposure routes. Food web models are presented for the terrestrial and aquatic marine food webs present at the site in Figures 2 and 3.
Conceptual Site Model. The conceptual site model (CSM) connects and clarifies what is already known environmentally about a site that is pertinent to decision-making requirements. In the case of chemical exposures, the CSM addresses contaminant pathways, receptors and considers possible exposures. Terracon previously addressed the elements of the CSM by completing a MRBCA Tier 1 Report for Site #2 through Site #8 in April 2010, following MDNR comment (Terracon Project Number 02087037). Information to complete the MRBCA Tier 1 evaluation was collected from the previous assessment activities. Additionally, Brownfields Characterization for Remedial Design sampling was conducted across the site in 2012 to provide better data density and visual classification of on-site fills. Based on review of previous soil analytical data, the soils have been generally delineated on-site to Risk Based Target Levels (RBTLs) for Soil Type 2 (Silty Soil) per Section 5.8.1 of the MRBCA Guidance Document. Based on the soil concentrations at the site and evaluation of the potential exposure pathways associated with the site, two dominant exposure pathways are associated with the site: Surface and Subsurface Soil (current and future non-residential) protective of ingestion, inhalation (outdoor vapor emissions and particulates) and dermal contact with surficial soils. Surface water runoff to the stream. Based on review of soil and groundwater analytical data, the vertical and horizontal extent of on-site impact has been characterized, with the possible exception localized areas between existing sample points. With respect to the current land use and current site conditions arsenic and lead representative concentrations in surface soil and subsurface soil are above the applicable Tier 1 RBTLs for Non-Residential Land Use Soil Type 2 for areas of the site that are not covered by concrete washout. Additionally, individual benzo(a)pyrene concentrations exceed Tier 1 RBTLs for non-residential use. Groundwater in the West Xxxxxxx area was not present with concentrations either above analytical detection limits or above DTLs for groundwater, detailed in the 2008 Site Investigation report. Appendix B provides tables of the soil data collected from the surface and subsurface soils and fills. Based on the complete exposure pathway: ingestion, inhalation (vapor emissions and particulates) and dermal contact; impacted soils/fill material exceeding Tier 1 MRBCA levels will be excavated and disposed at a certified ...
Conceptual Site Model. The Contractor shall develop a revised CSM in 3-D to include establishing or updating existing fate and transport models based on existing data and data gathered during the SSI. The CSM should cover the source area and the distal plume, to include the lateral and vertical extent of the contaminants in the context of geologic/hydrogeologic parameters and the remedial actions conducted to date.
Conceptual Site Model. Task 1 of the study will be a detailed site characterization from which a conceptual site model will be developed. The site characterization will include collecting new data, as well as leveraging existing data and previous studies. The purpose of the site characterization is to 1) provide baseline data, which will be required for the site-specific modeling in Task 2; and 2) gain an enhanced understanding of the physical system that will be impacted by coastal hazards including storm wave flooding, tidal inundation, and erosion of the cliffs, and beach and dunes at Asilomar SB. Data to be collected will provide a backshore characterization wherein data fall primarily in the categories of geologic and geomorphic information including lithology and thickness of seacliff- forming units, cliff/dune toe and top elevations, and slopes of the beach-cliff system. Part of the data collection will use an unmanned aerial vehicle (UAV- drone) equipped with a camera to collect imagery that will then be processed to derive current topographic elevation data. This step is important, as the most recent available elevation data (lidar) available for this area was collected in 2017, and outcomes of the hazard modeling in Task 2 will have significantly higher confidence if modern, updated topographic data is used. From this topographic data, various geomorphic information can be extracted such as cliff edge elevations, dune crest elevations, beach widths, etc. In addition to data collected in the field, data and information from existing geologic mapping and reports will be reviewed and used to inform the development of the backshore characterization. This task includes a site visit and mapping review which provides a comprehensive understanding of the physical system and the processes that drive change. As part of Task 1, and also critical to future modeling, we will compile storm data and historical records that will be used in Task 2 to verify model results. Task 1 will also inventory and compile any parcel and structure footprint data that is new since the previous VA was conducted. Task 1 Deliverables • Technical memorandum identifying methods, data sets used and any backshore characteristics. • All new geospatial data including aerial imagery, elevation data, and backshore characterization.
