Études de cas

Soil Removal and Confirmation Sampling for Redevelopment

J.S. Held rachète Shechter & Everett pour développer sa comptabilité judiciaire dans le domaine du droit de la famille en Floride

En savoir plus fermer Créé avec Sketch.
Accueil·Soil Removal and Confirmation Sampling for Redevelopment

Contexte

A developer initiated grading activities for a multi-family residential redevelopment project on a four-acre property in Santa Ana, California, in 2016. During construction, the project contractor identified petroleum hydrocarbons. Impacted soil was excavated and staged, and an initial soil sample collected at 15 feet indicated gasoline-range total petroleum hydrocarbons (TPH-g) and fuel-related volatile organic compounds (VOCs).

Our experts were retained to monitor VOC vapors in accordance with South Coast Air Quality Management District Rule 1166 and to oversee additional excavation activities. Further assessment of the extent of impacts was required to define the limits of the affected soil.

Nos conseils

Our experts evaluated site conditions and conducted an additional assessment by excavating seven potholes around the perimeter of the initial excavation and collecting supplemental samples. Gasoline-range hydrocarbons and VOCs were detected in three of the seven locations at the north end of the excavation. Based on these findings, excavation boundaries were expanded to address remaining impacted soils.

The excavation was enlarged to approximately 70 by 100 feet and extended to a depth of 19 feet, where groundwater was encountered. A total of approximately 3,200 cubic yards of soil was removed and disposed of off-site as non-hazardous waste. Our team collected 73 confirmation samples from multiple depths along excavation sidewalls and bottom, as well as from eight additional perimeter potholes. Results demonstrated that the affected soil had been removed, and the excavation was backfilled with engineered fill, allowing construction to resume.

In 2018, our experts conducted verification sampling of soil, soil vapor, and groundwater from five borings installed around the excavation limits to a depth of 20 feet. Soil and groundwater samples were analyzed for VOCs, TPH-g, TPH-d, and TPH-mo, and soil vapor probes were installed at depths of 5 and 17 feet. Results indicated:

  • No detection of TPH in soil or groundwater samples
  • Trace VOCs in one soil sample and one groundwater sample
  • Detection of TPH-g in two soil vapor samples and VOCs in one soil vapor sample at 17 feet

Our experts determined that remaining hydrocarbon contaminants were below screening levels for direct exposure and did not impact groundwater. Soil vapor results at shallow depths indicated that vapors were not migrating toward the surface, and the vapor intrusion risk was determined to be unlikely.

Domaines d'activité associés

> Environmental Risk and Compliance
Notre équipe fournit des conseils d’experts sur la détection et la réduction du risque en matière environnementale et développe des solutions pour garantir un respect des normes EHS et une supervision indépendante.

 

> Environmental, Health, and Safety
J.S. Held dispense des services de conseil et d'expertise en matière d'environnement, santé et sécurité, portant notamment sur les dommages environnementaux et leur remédiation, le devoir de diligence environnemental, la transition énergétique, la toxicologie et l'épidémiologie, l'hygiène industrielle, la gestion responsable des produits et la garantie des produits, ainsi que la santé et la sécurité des personnes.

CONTACTS CLÉS

For additional information about the engagement or to learn more about our services, contact:

Nos experts