Management of Contaminated Soil. Click to edit Master subtitle style Peter Langtry, P.G., C.E.G Senior Principal Geologist

Transcription

1 Management of Contaminated Soil Peter Langtry, P.G., C.E.G Senior Principal Geologist

2 Objectives Describe common soil contamination issues that can be encountered during construction/infrastructure projects Present strategies to minimize impacts to budgets and schedules

3 Why is this Important? Construction projects in urban areas can encounter a variety of contaminants in soil, soil vapor and ground water. Even on projects without contamination issues, documentation on soil quality is required if excess soil is to be disposed off-site. A lack of planning can lead to significant cost and schedule impacts. Documentation of conditions will help determine appropriate health and safety measures.

4 Examples of Contamination Pesticides and heavy metals in surface soil from prior agricultural use. Petroleum hydrocarbons from releases from underground storage tanks (USTs). Aerially deposited lead (ADL) along roadways. Metals, pesticides, PCBs and petroleum along railroad tracks. VOCs in trench air originating from VOC contaminated soil or ground water Naturally Occurring Asbestos (NOA)

5 What to do?

6 Phase I Environmental Site Assessment Evaluates history aerial photographs, maps, interviews. Identifies reported hazardous materials incidents on or near the project. Site visit to evaluate current hazardous materials use/storage Can be performed for a linear infrastructure corridor

7 Historic Map Example

8 Phase II Sampling - Soil Collect samples to full-excavation depth Select laboratory analyses based on known or suspected contaminants (based on Phase I ESA) Should be performed by environmental professional Department of Toxic Substances Control (DTSC), Clean Fill Advisory (2001) guidance for sample frequency and analyses

9 Sample Collection Soil sampling can be performed using hand sampling if near-surface. A drill rig or backhoe can be used to collect deeper soil samples. Many jurisdictions require drilling permit depending Click to on edit depth Master of exploration. subtitle style

10 Stockpile Sampling If sampling/analyses are not possible before construction, sampling can be performed from stockpiled soil. Should have a stockpiling location designated that can allow time for sampling, Click to analyses, edit Master and subtitle disposal style profiling. Sample in accordance with disposal facility requirements or DTSC Clean Fill Guidance.

11 Other Considerations Ground water sampling if excavation dewatering will be required. Soil vapor sampling if excavations extend close to contaminated soil or ground water. Most laboratories have a standard 1-week turn around time for analyses, and charge significantly Click to more edit for Master rush analyses. subtitle style Last minute rush sampling can significantly increase costs, and laboratory may be unable to meet quick turn arounds if they are busy.

12 Phase II sampling plan should be developed and implemented by an environmental professional. Boring logs, sample locations, sampling protocol, laboratory analytical reports, and professional s Click to edit interpretation/opinion Master subtitle styleshould be included with sampling report.

13 Interpretation of Laboratory Results Environmental professional should interpret the results and compare to applicable screening levels and hazardous waste limits. Compare concentrations detected in soil to hazardous waste limits and disposal facility acceptance criteria. If soil is to be reused on-site or at another site, compare to residential and commercial ESLs, RSLs and CHHSLs

14 Example Results

15 Types of Wastes Class I California, non-rcra Hazardous Waste Class I Federal RCRA Hazardous Waste Class II waste Unrestricted (soil that meets residential/unrestricted Click to edit Master screening subtitle style levels. Sometimes referred to as Class III waste)

16 Hazardous Wastes Regulatory criteria to classify waste as a California hazardous waste for handling and disposal purposes are contained in the California Code of Regulations (CCR), Title 22, Division 4.5, Chapter 11, Article 3, Criteria to classify waste as Resource Conservation and Recovery Act (RCRA) hazardous are contained in Chapter 40 of the Code of Federal Regulations (40 CFR), Section 261. Wastes may also be classified as hazardous based on other criteria such as ignitability, corrosivity and reactivity.

17 What is Naturally Occurring Asbestos (NOA)? Mineral found in mafic & ultramafic rocks across the US & around the world Mafic (igneous & metamorphic: high in Mg & Fe) Ultramafic (igneous & metamorphic: high in Mg & Fe, low in silica) Mined in US from for use in building materials as manufactured asbestos Serpentine named state rock of California in other states have outcrops of mafic & ultramafic rocks

18 Asbestos bearing rock in San Jose Jsp = Jurassic Serpentinized harzburgite & dunite (igneous rocks)

19 Places Asbestos (NOA) can be found outdoors Rock outcrops Fault zones Soil Imported fill or roadbase Decorative rock used in landscaping Hillside in Oakland, CA

20 Asbestos Regulatory Limits Asbestos content in material (rock/soil) CARB / BAAQMD: 0.25% DTSC: 0.01% Title 22: 1% Possible local regulations- cities/counties Asbestos Dust Mitigation Plan (ADMP) required by BAAQMD if greater than 0.25%

21 Management of Known Contamination Prepare a Soil Management Plan (SMP) SMP summarizes history of the project site, known soil quality/test results, and areas of potential concern (AOC). Can be incorporated into construction bid/contract documents. Can incorporate an ADMP if required due to presence of asbestos. SMP may be required by regulatory agency.

22 Management of Unexpected Conditions SMP should provide guidance to contractors in the event unidentified/unexpected conditions are encountered. Hazard recognition Contact information Site access control Sampling/analytical requirements

23 Summary Prepare Phase I ESA and perform Phase II sampling early in planning process, if possible. Prepare a SMP, and if appropriate incorporate into contractor bid documents or project Click to specifications. edit Master subtitle style

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