Displaying items by tag: Commercial

Visitors walk the trail during the wildflower bloom at Table Mountain, a basaltic plateau near Oroville, California. Photo taken April 22, 2019.Kelly M. Grow / California Department of Water Resources, FOR EDITORIAL USE ONLYThere are many reasons why you might need to hire an environmental consulting firm. Here are some of the most common:

To Comply With Environmental Regulation

Environmental regulations are becoming increasingly complex and stringent, and it can be difficult for businesses to keep up without the help of an expert. Environmental consultants can help you identify and understand the regulations that apply to your business, develop a plan to comply with them, and keep track of changes in the law.

To Assess Enviornmental Risks

Environmental risks can pose a significant threat to businesses, both in terms of financial liability and operational disruptions. Environmental consultants can help you identify, assess, and manage environmental risks at your property or facility. This may include conducting environmental site assessments, analyzing air and water quality, and performing hazardous waste evaluations.

To Remediate Enviornmental Contamination

If your property or facility is contaminated with hazardous substances, you will need to take steps to remediate the contamination. Environmental consultants can develop and implement remediation plans, oversee the cleanup process, and ensure that the cleanup meets regulatory standards.

To Obtain Environmental Permits

Many businesses need to obtain environmental permits to operate. Environmental consultants can help you prepare and submit permit applications, provide technical support during the permitting process, and ensure that your business complies with permit requirements.

To Develop and Implement Sustainability Plans

drilling a contaminated siteBusinesses are increasingly adopting sustainability practices to reduce their environmental impact and improve their corporate image. Environmental consultants can help you develop and implement sustainability plans that align with your business goals and objectives.

To Conduct Enviromental Training for Employees

Environmental training can help employees understand environmental regulations, identify environmental risks, and take steps to protect the environment. Environmental consultants can develop and deliver environmental training programs that are tailored to the needs of your business.

To Respond to Environmental Incidents

Environmental incidents, such as spills, leaks, and fires, can have a significant impact on businesses. Environmental consultants can help you respond to environmental incidents quickly and effectively, minimize environmental damage, and comply with regulatory requirements.

To Stay Up-to-Date on Environmental Issues

Environmental issues are constantly evolving, and it can be difficult to keep up with the latest developments. Environmental consultants can provide you with up-to-date information on environmental issues and help you understand the implications for your business.

Why Would You Need an Environmental Engineering Firm

You might need an environmental engineering firm to comply with environmental regulations, assess human health risk, assess financial risk, or cleanup contamination. These are just a few of the reasons - you might think of others. For example, you might need an environmental firm to remove an old heating oil fuel tank. Let us know. Click the button below or a free consultation or call at (831) 227-4898

fresh air at sunsetIn addition to asking for soil gas samples, many state and county environmental health agencies in California ask for indoor air samples. Let’s take a look at the "five Ws and a H” of an indoor air sample - or the what, why, who, when, where, and how of an indoor air sample.

What is an Indoor Air Sample?

An indoor air sample is what you get when you remove a small portion of the air inside an indoor space and isolate it for testing. Air inside a building can contain suspended particles, chemicals from inside the building, chemicals from outside the building, and chemicals from soil and water beneath the building. At some level, these airborne particulates and chemicals become harmful to human health. One strategy used to protect human health is to take a look at the chemical makeup of indoor air by collecting and analyzing indoor air samples. By the way, a volume of air is approximately 21% oxygen, 78% nitrogen, 1% argon, and 0.04 percent carbon dioxide.

Where underground chemical contamination is a concern, a sample of indoor air can be used to find out if contaminated soil gas has entered the buildings above it. Contaminated soil gas entering an indoor space can contain chemicals such as gasoline and cleaning solvents (tetrachloroethylene or PCE). Contaminated soil gas may also have by-products of chemical spills like the vinyl chloride that comes from the breakdown of PCE.

Why get an Indoor Air Sample?

Indoor air is sampled to look for the presence of particulates and/or harmful gasses that are either naturally occurring or the result of a spill. The samples are analyzed to find out what particulates or chemicals are in the air, what the levels are, and what the risk to human health is. Particulate or chemical levels detected at the lab are typically assessed by comparison against levels judged to be safe by the regulatory community. These levels, sometimes called environmental screening levels (ESLs), are considered safe becuase they were shown not to pose a risk to public health and the environment.

Who is the Indoor Air Sample For and Who Collects the Sample?

In most cases an environmental consultant or environmental oversight agency proposes collection of indoor air samples. Sometimes building owners hire an environmental consultant to collect indoor air samples as a precautionary matter. Indoor air samples are tyoically collected by personnel trained in indoor air sampling and related health and safety concerns. Sampling objectives and methods are typically spelled out in a work plan that is approved by the regulatory oversight agency prior to samping.

Where are Indoor Samples Collected and Where do They go?

Indoor air samples are collected in indoor spaces away from walls, windows and doors. In the case of soil gas contamination, bathrooms or utility rooms are targeted because pipes and utilities that go through the building floor are places where contaminated soil gas can enter a building. An indoor air sample is collected in mid-air, about 4 to 5 feet above the floor. Once the air samples are collected, they are taken to a laboratory for chemical testing.

Indoor air samples go to a state-certified laboratory for analysis. Sample containers are labeled with the sampling location, time sampling started and stopped, the initial and final canister pressure, and the sample identification. After labeling, the samples are placed in a sealed container and transported to a lab for analyses.

A chain of custody is prepared at the point of sample collection and travels with the samples to the laboratory. The chain of custody contains contact information, a list of the samples collected, and instructions on analysis. Each person that handles the samples during the trip from the sample location to the laboratory signs and dates the chain of custody, so that if anything happens to the samples, there is a clear line of responsibility from the sample location to the laboratory.

When are Indoor Air Samples Collected and When do the Results Arrive?

Indoor air samples can be collected at any time. For contaminated soil gas, it is suggested that indoor air samples be taken twice per year to show levels during rainy and dry seasons. Indoor air samples are collected over a time period that usually spans 8 hours, but sometimes extends to 24 hours. One specific method of indoor air sampling allows sampling periods of up to a month. Once at the lab, it usually takes about two weeks to get the results. Of course, if you are willing to pay more, sample testing can be “rushed”.ambient air sample

How are Indoor Air Samples Collected?

Indoor samples are collected using a vacated stainless steel canister, a passive sampler (container of adsorption material), or a combination or pump and adsorption material, any of which are supplied by a laboratory.

The canister is delivered sealed and under a vacuum. The canister is equipped with a valve that controls the air flow into the canister. The laboratory sets the flow rate according to the sample period. For example, the valve for an 8-hour sample is set to limit the air flow so that it takes about 8 hours to fill the canister. During sampling, the canister is mounted about 4 to 5 feet above the floor. Sample collection stops after sample period or when the canister pressure gauge shows the canister is nearly filled.

Passive air samplers work by allowing natural air currents to bring air into contact with a material that certain airborne chemicals stick to (adsorb). Chemicals that stick to the adsorbent material are later removed at the lab and tested to find out what chemicals are in the air and at what levels. Passive samplers are placed just like canister samplers and sampling periods can extend up to a month. Some passive air samplers come in the form of a badge that is worn by someone who could be exposed to particulates or chemicals in the workplace. If a certain particulate or chemical level is reached, the badge turns color or emits a sound.

Indoor air is also sampled using an air pump combined with an absorption material as used in passive air samplers. In this case, instead of relying on the natural air movement inside a building, a specific amount of air is collected at a set air flow using a pump. As with the passive method, chemicals that stick to the adsorbent material are later removed at the lab for analysis.

Close

Here we answered the five Ws and a H for an indoor air sample. If you have any other questions about indoor air sampling, or need help with another environmental question, please call us or click the button below for a free consultation.

Soil gas sample set up“What is a Soil Gas Sample?”

It’s a good question. It’s part of a string of questions most of us are familiar with -  the what, why, who, when, where, and how of something. Let’s check the list.

What is a Soil Gas Sample?

A soil gas sample is what you get when you remove a small portion of gas inside soil and hold it in a container for testing. Underground soil is like a sponge in that it has empty spaces. Between the surface of the ground and underground water (groundwater), these soil spaces are filled with gas and water. The gas is mostly air, but it can also have gaseous contamination from underground spills of chemicals such as gasoline and cleaning solvents (tetrachloroethylene or PCE). The soil gas may also have by-products of chemical spills like the vinyl chloride that comes from the breakdown of PCE.

Why get a Soil Gas Sample?

Soil gas is sampled to see if there are any harmful gasses that are either naturally occurring or the result of a spill. The samples are usually analyzed at a State-certified lab to find out what chemicals are in the soil gas sample and what the levels are. There are several reasons to collect a soil gas sample.

One reason is to find out if there is a risk to human health and the environment. To check for risk, chemical levels detected at the lab are typically compared to levels judged to be safe by the regulatory community. These levels, sometimes called environmental screening levels (ESLs), are considered safe when they do not pose a potential risk to public health and the environment.

Another reason to collect soil gas samples is to find out where contamination is and where chemical levels are highest. A map showing where chemicals are found and at what levels they are found can provide a good idea of the area of contamination and highlight areas with higher levels. This can help to steer property development plans and keep people away from potentially harmful areas. This information can also significantly lower investigation costs by showing where soil and groundwater sampling should be targeted.

In the case of known underground contamination, soil gas samples may be collected over a period of time to monitor the change in chemical levels. A change that shows a decrease in chemical levels is necessary for environmental case closure.

Sometimes the reason for soil gas sampling is to just find out whether there is underground contamination. For example, a property owner may have soil gas samples collected along a property boundary shared with a dry cleaning business to find out if contamination from the dry cleaner moved beyond the dry cleaner’s property line.

Who is the Soil Gas Sample for and Who Collects the Sample?

Usually, an environmental consultant or environmental oversight agency proposes collection of soil gas samples. As mentioned above, the reasons are to find out what chemicals are in the soil gas, what the levels are, and where the chemicals are located.

In most cases, personnel trained in soil gas sampling collect soil gas samples. Sampling goals and how the sampling will be done are typically spelled out in a work plan that is approved by a regulatory agency prior to samping.

Where are Soil Gas Samples Collected and Where Do They Go?

Soil gas samples are collected in areas of known or suspected underground contamination. Once the soil gas samples are collected, they are taken to a laboratory for chemical testing. In some cases, an on-site field laboratory is used to analyze samples.

In the field, soil gas sample containers are labeled with the sampling location, time the sample was collected, and a sample identification number. After labeling, samples are placed in a sealed container and transported to a state-certified laboratory for analyses. 

A chain of custody is prepared at the point of sample collection and it travels with the samples to the laboratory. The chain of custody contains contact information, a list of the samples collected, and other important information. It is a clear line of responsibility from the sample location to the laboratory.

When are Soil Gas Samples Collected and When do the Results Arrive?

Soil gas samples can be collected at any time, but it is suggested that samples not be collected within 5 days of a good rainfall. Policy makers suggest that after you know where the soil  gas contamination is, you should take samples twice per year to show levels during rainy and dry seasons. Once at the lab, it usually takes about two weeks to get the results. Of course, if you are willing to pay more, sample testing can be “rushed”.

How are Soil Gas Samples Collected?

Soil gas sampling equipment and wellSoil gas samples are collected from wells installed to at least 5 feet underground or from sample points that allow access to soil just underneath a concrete floor. In most cases samples are collected using a stainless steel canister that is supplied by a laboratory. The canister is delivered sealed and under a vacuum. During sampling, the canister is attached to a manifold that connects the canister to the well or sample point. The manifold is also equipped with pressure gauges, a filter, and a flow limiter that controls the flow of soil gas into the sample container to maintain sample quality. Sample collection stops when the canister pressure gauge shows the canister is nearly filled.

Close

We answered the five Ws and a H for a soil gas sample. There are plenty of questions to ask about soil gas, contamination, and exposure at our homes and workplaces. We are here to help answer those questions and provide related services such as soil gas sampling and vapor intrusion mitigation system design,  installation, and monitoring.

If you have any other questions about soil gas, or need help with another environmental question, please call us or click the button below for a free consultation. We’ve been helping folks for 35 years and we know what we are doing.

removeUST

California's RUST Program

RUST stands for Replacing, Removing, or Upgrading Underground Storage Tanks.

The RUST program is a system of grants and loans to help small business owners and operators come into compliance with regulatory requirements for underground storage tanks (USTs). Compliance is achieved through removing, replacing or upgrading USTs. The program is administered by the State Water Resources Control Board.

The RUST Program is a great way for small businesses to protect their business and improve their bottom line. By removing or upgrading their USTs, businesses can reduce their risk of environmental liability and save money on maintenance and repairs.

California's Deadline for the Removal of Single-Walled USTs is December 31, 2025

California has reminded owners and operators of underground storage tanks (USTs) that they are required to permanently close single-walled (SW) USTs by December 31, 2025. This includes connected SW piping. With the deadline looming, it’s time to learn about California’s Replacing, Removing, or Upgrading Underground Storage Tanks (RUST) Program.

What Costs are Eligible for a RUST Grant or Loan?

Eligible costs for grants include:

  • Costs for removing and replacing single-walled* USTs and/or piping with doubled-walled** USTs and/or piping.
  • Costs for upgrades to USTs including installation of containment sumps, under-dispenser containment boxes/pans, and electronic monitoring systems.
  • Costs for conducting enhanced leak detection tests.

Eligible costs for loans include those for grants and:

  • Costs for corrective actions necessary to meet applicable local, state, or federal standards including, but not limited to, any design, construction, monitoring, operation, or maintenance requirements adopted pursuant to the California Health and Safety Code.

*Single-walled USTs have one wall between the petroleum fuel and the underground soil.

**Double-walled USTs have two walls between the fuel and the underground soil. The second wall provides extra containment that helps to prevent leaks from reaching the soil. It is a tank in a tank (piping in piping) system.

Who is Eligible for a RUST Grant?

Independently owned and operated small businesses with petroleum USTs and fewer than 20 full-time and part-time employees are eligible for a RUST grant. The principal office and business officers must be domiciled in California. Businesses dominant in their field of operation are excluded.

The facility must have legally been in business retailing gasoline after January 1, 1999, and must have sold less than 1,500,000 gallons of gasoline annually for the two years prior to filing an application.

All USTs owned and operated by the applicant are in compliance with State UST regulations. Grant applicants may be eligible for a waiver from the permit compliance and/or retailing gasoline requirements if the project tanks will be removed and will not be replaced with new tanks and the applicant does not qualify for a RUST Loan. 

“Domiciled” means the permanent legal place of residence of a natural person or the principal place of business of a juristic entity.

“Dominant in their field of operation” means having more than twenty employees and a significantly larger market share than the next largest rival. Dominant firms are typically considered to have market shares of 40% or more.

ust exposed

Who is Eligible for a RUST Loan?

Independently owned and operated small businesses with petroleum USTs and fewer than 500 employees are eligible for a RUST loan. As with a grant, the principal office and business officers must be domiciled in California, and businesses dominant in their field of operation are excluded.

All USTs owned and operated by the applicant are in compliance with State UST regulations.

What are the RUST funding amounts?

If you are eligible for RUST funding, you cannot begin work until you have a grant or loan executed by the State Water Board. 

RUST Grant Funding Amounts

The RUST program grants are available for between $3,000 and $70,000 per grant.

A small business may receive multiple RUST grants, but the maximum lifetime limit in grant money for each small business is $70,000. 

RUST Loan Funding Amounts

Loan terms of 10 or 20 years at ½ the State’s most recent general obligation bond rate are available. Contact the State Water Board for the current interest rate.

Loans are available for between $10,000 and $750,000. 

Ten-year loans are secured by a Uniform Commercial Code Financing Statement on the business property, assets, and equipment. Twenty-year loans are secured by a deed of trust on the business property and a Uniform Commercial Code Financing Statement on the business property, assets, and equipment. 

Additional collateral and guarantees may be required to provide sufficient security for the loan. The borrower must pay a loan fee of 2 percent at the final loan closing.

How to Finance UST Removal in California

The State Water Resources Control Board offers grants and loans to help small business owners and operators come into compliance with regulatory requirements for USTs. Compliance is achieved through removing, replacing, or upgrading USTs.

We talked about eligible costs, eligibility requirements, and funding. Are you considering replacing, removing, or upgrading USTs? Give us a call at 831-227-4898 or click below for a free consultation.

Understanding the Costs of a Phase I Environmental Site Assessment (ESA)

Understanding the Costs of a Phase I Environmental Site Assessment"Why does it cost so much for a Phase I Environmental Site Assessment?" This is the most common question from prospective clients seeking this type of service. After all, the product is simply a large document outlining the detailed history of the property. How difficult is that?

First, understand that all Phase I Environmental Site Assessments (ESAs) must be conducted using the guidelines in the American Society of Testing & Materials (ASTM) Standard for Phase I ESAs. Following the ASTM standard assures protection from environmental damage caused by previous property owners.

Okay - so why does it cost so much? Let’s start with what it takes to prepare a Phase I site assessment according to the ASTM standard.

What are the Phase I Preparation Steps in an Environmental Site Assessment?

The preparation of a Phase I ESA can be broken down into the following steps:

  Step

Time to Complete
(hours)

1) Initial property evaluation

1 - 3

2) Government data request

2

3) Local records request and file review

2 - 6

4) Data review and client communication

1 - 2

5) Government records review

12 - 16

6) Historical records review

8 - 12

7) Interviews with persons knowledgeable of property history

1 - 2

8) Property inspection

2 - 8

9) Report preparation

10 - 16

10) Report review and submittal

1 - 3

Total Hours

40 - 70

 

What Drives the Cost of an Environmental Site Assessment?

Government and Historical Records Review

A large amount of time is spent on conducting a thorough investigation into the current and historical uses of the property under review. This is done by reviewing governmental and historical records. As seen in the table above - this takes up to 28 hours. 

Many Phase I providers turn to Environmental Data Resources (EDR), a company that tailors their products to comply with the ASTM Standard. EDR searches hundreds of federal, state, local, and tribal databases using the property as the focal point. An EDR database package for Phase I costs about  $375.

EDR coverLocal governmental agencies are also contacted for records related to the property under review. These agencies can include local fire departments, environmental health agencies, building departments, and tax assessors (for verifying property characteristics). Some agencies have their files available online, others will copy requested files and mail a CD, and others require an in-person visit to their office to review the files.

Historical records such as air photos, street directories, topographic maps, and fire insurance maps (Sanborns Maps) are also reviewed to provide information on past uses of the subject property. For example, if the local governmental agencies have no records of any USTs being used at the property, but an air photo from 1949 shows a gas station canopy on the property, then we’ll cross-check the historical street directories to see if a gas station existed at the property during this year.

Interviews, Inspection, and Reporting

Along with records review, interviews are conducted, the site is inspected, and a report of findings is prepared - according to the table estimate, up to 29 hours of work.

Completing a Phase I ESA can take at least 40 hours, with the average being around 52 hours. We quote most of our Phase I ESA projects between $4,200 and $5,500,on a fixed fee basis.

 

Why does the Phase I Report cost so much more than the Environmental Data Resources (EDR) Report?

To meet the ASTM Phase I standard, an Environmental Professional must conduct, or be responsible for conducting a Phase I ESA. The EP and staff must have sufficient education, training, and experience to conduct a Phase I ESA, and that drives cost.

mapsThe cost of an EDR report is fixed at a low price because it is primarily a computer-generated database dump. On the other hand, the EP and their staff sift through the EDR report, inspect the site, conduct interviews, and review historical information. They gather all the relevant information and summarize it in a Phase I report that includes conclusions and recommendations. It is these recommendations and conclusions that commercial real estate transactions depend upon. That is what drives the cost far above the cost of an EDR report.

Close

Our Phase I ESA preparers are well-qualified, with over 30 years of experience in the industry. We are here to answer your questions, and our initial consultation is always free. Click the button below to schedule a consultation or call us today at (831) 475-8141.

Understanding Vapor Intrusion Assessments

An attorney we work with asked me to look at a phase I environmental site assessment (ESA) for his client. His client was really interested in the property, which already had a solid lease.

The ESA disclosed a historically recognized environmental concern (HREC) and a recognized environmental concern (REC). Both had to do with a release of gasoline from a former underground storage tank (UST) at the property. The property had environmental case closure with very low levels of gasoline contamination left in place.

The question posed by the attorney’s client boiled down to the Phase I recommendation - “Complete a Vapor Intrusion Assessment and Prepare a Soil Management Plan”.

“Is this necessary?” the client asked.

I told them that the recommendation was very conservative based on the information provided by the ESA. I let them know that if they planned to redevelop the property, the county would probably look to them to voluntarily investigate for vapor intrusion and prepare a soil management plan as part of the redevelopment.

I advised that the recommendation was overly conservative given their intention to hold the property as is. I also told them that it was unlikely a vapor intrusion assessment would disclose a vapor intrusion problem.

As we were wrapping up, a question came up, “What is a vapor intrusion assessment?”

I started my answer with an explanation of vapor intrusion.

What is Vapor Intrusion?

As a liquid chemical evaporates, it turns from a liquid into a vapor or gas. All liquids evaporate to some extent, and the extent to which a liquid evaporates shows its volatility. The more volatile a liquid is, the more quickly it turns into vapor.

When a liquid chemical leaks into the ground, it enters the soil and groundwater. Once in groundwater, the chemical moves along with the groundwater. As this process unfolds, and depending on its volatility, some of the released chemicals turn into a vapor and enter the space of dry soil above the groundwater. The vapor can leak up through the ground and enter a building causing a buildup of chemical vapors in the building. This process is vapor intrusion.

What is a Vapor Intrusion Assessment?

vaporintrusionAs time goes on, groundwater carries the dissolved chemical downstream from the chemical release. At the same time, a vapor plume (just like the billowing smoke that forms above a smokestack) forms in the soil above the affected groundwater. The area of the vapor plume mirrors the area of chemically-affected soil and groundwater.

A vapor intrusion assessment uses the link between the vapor plume and affected soil and groundwater to confirm whether there is contaminated soil and/or groundwater in an area and to determine whether any detected contamination poses a human health risk due to vapor intrusion.

In practice, a vapor intrusion assessment involves collecting soil vapor samples from small wells spread across the area you are investigating, and testing the soil vapor samples for suspected contaminants.

Typically, detected contamination levels in soil vapor are used to estimate how much area is contaminated, identify areas of high contamination or “hot-spots”, and gauge potential human health risks by comparing detected levels with published environmental screening levels (ESLs).

What are the Advantages of a Vapor Intrusion Assessment?

A vapor intrusion assessment has some real advantages over the more traditional phase II soil and groundwater assessment for figuring out where soil and groundwater contamination is, where the highest levels of contamination are, and whether soil vapor intrusion poses a human health risk.

Number one, a soil vapor assessment costs much less than a soil and groundwater assessment, generates less waste, is less intrusive, and provides information that can be used to target a groundwater and soil investigation, and possible cleanup. Additionally, a soil vapor assessment can be used to examine vapor intrusion health risks.

Of course, a soil vapor assessment does not provide all the information a soil and groundwater investigation can, but it gets you well down the road and allows more efficient and cost-effective phases of investigation and cleanup.

Our recommendation: Before drilling for soil and groundwater samples, use a soil vapor assessment to get a valuable overview.

Close

In this article, we took a look at soil vapor intrusion, explained what a soil vapor assessment is, and described some of the advantages a soil vapor assessment has over a traditional phase II soil and groundwater investigation.

If you have a Phase I ESA that recommends verifying an HREC or REC, go ahead and get a second opinion, and if necessary, consider using a soil vapor assessment to confirm the ESA recommendation. With over 30 years of experience in conducting soil vapor assessments and reaping their advantages, we can help. Please call us at 831-475-8141 or click below to schedule a free consultation.

IMG 1859Groundwater monitoring is a crucial aspect of environmental management, helping to detect and manage potential groundwater contamination. However, the frequency and duration of monitoring can vary depending on site conditions and regulatory requirements. This page from Remediation Risk Management provides valuable insights into determining the necessary amount of groundwater monitoring, factors that affect monitoring requirements, and how to determine the appropriate frequency and duration of monitoring.

Everything has a beginning, middle, and end - even groundwater monitoring.

The Beginning. After contamination is identified in groundwater at a property, it’s common practice for the local environmental oversight agency to require groundwater monitoring. In California, the response to groundwater contamination is prescribed in State Water Resources Control Board Resolution 92-49 (SWRCB 92-49). This usually comes in the form of a regulatory directive - a letter arrives in the mailbox.

The Middle. The directive usually requires investigation, cleanup, and reduction of contamination by completing the following phases under their oversight:

1. Initial site assessment

2. Soil and groundwater investigation

3. Cleanup and reduction

4. Verification monitoring

The thing is, groundwater monitoring usually begins with initial site assessment and ends with long-term verification monitoring - which may take up to 10 years to complete. 

What is groundwater monitoring? In essence, it’s measuring how deep groundwater is below the ground and collecting samples of groundwater for various tests. Groundwater is reached through wells that can be temporary or permanent. The wells are built in holes drilled through the soil into the groundwater. Sometimes, no well is used and groundwater is monitored using a bare hole. 

During the initial site assessment phase, groundwater monitoring is used to identify the type and general location of contamination. During investigation and cleanup, groundwater monitoring is used to observe changes in contaminated groundwater and the effects of cleanup and contamination reduction. Long-term verification monitoring is used to build confidence that contamination left in place will not cause future problems.  It's easy to see how groundwater monitoring seems to go on and on.

Groundwater monitoring is done to answer the following questions:

  • What contaminated the groundwater?
  • Where is the contaminated groundwater?
  • How contaminated is the groundwater?
  • What direction does the groundwater flow?
  • How does the contaminated groundwater change over time?

The answers to these questions provide much of the information used to complete investigation, cleanup and reduction of contamination - and receive environmental case closure.

figure

As more information about the groundwater contamination becomes available, groundwater monitoring becomes more focused. As a result, it might be possible to reduce monitoring costs by reducing the monitoring frequency, the number of wells monitoring, or the number of tests performed.

The End. Groundwater monitoring ends when contamination levels no longer need watching. All the questions about groundwater contamination have been answered.

Early on - the what, where and how of contaminated groundwater are answered in the preliminary and investigation phases. Contaminant cleanup and reduction continue, and after a few years the seasonal patterns of groundwater flow and contaminant levels are generally understood. Over this period, the decrease in groundwater contamination over time is well established. There comes a point where the groundwater monitoring information shows that even with groundwater contamination safely left in place, cleanup goals will be reached in a reasonable time.

Finally verification monitoring is done to record final site conditions for environmental case closure. Groundwater monitoring usually stops at this point because in most cases verification monitoring supports case closure.

Groundwater monitoring begins with a regulatory directive and ends with a regulatory directive; No Further Action - Case Closure.

Close

We answered the question about how much groundwater monitoring it takes. We described the beginning, middle and end of groundwater monitoring, and how it follows the phases of contamination investigation, cleanup, reduction and case closure. If you’re somewhere around the beginning, middle, or end of your own groundwater monitoring experience, and need some help or a second opinion, give us a call or click the button below for a free consultation.  We have over 30 years of experience in completing environmental investigation, cleanup and reduction - including groundwater monitoring.

Experienced Environmental Consulting in the Monterey Bay Area

You’re reading this because you are looking for an honest and reliable environmental consultant who will save you money, give you the answers you need, and provide reassurance. When confronted with an environmental issue, one of the most important questions you’ll have is, who are the best consultants in my area?

RRM wants to help prospective clients find the best company to meet their needs. We’ve been in business since 1992 providing cost-effective solutions to environmental challenges, and we understand the necessity for exploring other options. We compiled a list of local companies to help you narrow your search.

Experienced Environmental Consulting in the Monterey Bay Area

Here are our top picks for Environmental Consultants in the Monterey Bay, CA area

Weber, Hayes, & Associates

Located in Watsonville, WHA has been providing environmental and geotechnical services since 1988. They have extensive experience providing services to the agricultural industry, including guidance on stormwater conveyance and detention, and waste discharge for composting operations.
(831) 722-3580
www.weber-hayes.com

Aero-Environmental Consulting

This company operates from Monterey and offers a wide range of environmental testing and inspection services in areas such as industrial hygiene, building science, and specialty construction. Their industrial hygienist provides consulting in indoor air quality testing, indoor environmental services, and environmental analysis.
(831) 277-5831
www.aero-enviro.com

Trinity Source Group, Inc.

Established in 2005, Trinity is located in downtown Santa Cruz. They offer a broad range of environmental consulting, management, and construction services with a turnkey approach to environmental challenges. This includes providing drilling services in addition to environmental services.
(831) 426-5600
www.trinitysourcegroup.com

Red Hills Environmental

Based in Los Gatos, RHE offers a full range of professional and technical services for the investigation, remediation, and management of difficult environmental conditions. They are great at helping people understand tricky compliance situations.
(408) 455-9300
www.redhillslg.com

While cost is always one of the first topics you might discuss, you might also want to hear about their experience in dealing with your particular problem, about their relationship with the relevant county and state agencies involved, project timing, and what potential contract arrangements look like.

Close

We hope this post has provided you with information that helps you make the best choice. No matter which consultant you choose, we are here to answer any questions. Click the button below to schedule a free consultation or call us today at (831) 475-8141.

Wildflowers along a stream at Table Mountain a basaltic plateau near Oroville, California. Photo taken April 4, 2013.Florence Low / California Department of Water Resources

Effective Methods for Active Vapor Intrusion Mitigation

I got a call from an exacerbated client who was rightly concerned about a letter from the county. “The county letter said my neighbor has finished cleanup at their dry cleaner and they were implementing active vapor intrusion mitigation, “ she told me. We were helping this client navigate the issues, concerns and requirements regarding investigation and cleanup at a property adjacent to her own. “What is active vapor intrusion mitigation and what does it mean for our property?” she asked.

“Good question,” I told her. “I know we’ve already talked about vapor intrusion as it relates to your property, but let's go over it briefly, then we can talk about active vapor intrusion mitigation."

What is Vapor Intrusion?

“When we first spoke about investigation and cleanup at the dry cleaner next door, I told you there was a possibility that groundwater contaminated with tetrachloroethylene (PCE) traveled from beneath your neighbor's property to below your property,” I recalled. “I told you that PCE in the groundwater could contaminate soil vapor and contaminated soil vapor could enter the building on your property. Contaminated soil vapor traveling from an underground source into a building or building basement is vapor intrusion.”

“At the time, I let you know that soil vapor samples collected on your property showed there was no risk of vapor intrusion,” I said. “If we had found there was even a potential risk of PCE-contaminated vapor entering your building, we would have recommended active vapor intrusion mitigation (VIM) to keep vapors from entering into your building and to protect occupants from exposure.” 

“While cleanup has occurred next door,” I continued, “it wasn’t enough to eliminate the vapor intrusion threat posed by the remaining contamination. So, to allow safe occupancy of the building, your neighbor decided to use active VIM until cleanup goals are reached.”

“Okay, sounds reasonable,” my client said. “So what is active VIM?”

Active Vapor Intrusion Mitigation (VIM) Methods

Simply put, active VIM methods create a pressure difference between air on the inside of a building and the soil vapor under a building in a way that keeps vapors out of the building. Active VIM methods tend to be more effective than passive methods, but more expensive. These methods can be used on new and existing buildings, they have a successful track record of performance, they can be applied to a wide variety of site conditions, and simple pressure gauges show they work.

VIM methods require periodic maintenance and they have long-term energy and maintenance costs. Let’s consider three active VIM methods: sub-slab depressurization, sub-membrane depressurization, and building overpressurization.

1) Sub-slab Depressurization

Sub-slab depressurization systems are designed to provide continuous pressure reduction beneath a building’s floor and foundation. This method is for new or existing slab-on-grade foundations. Sumps, drain tiles and block wall foundations can also be depressurized. Depressurization refers to using a fan or blower to bring the air pressure in the sub-slab venting layer down below the air pressure in the building. In this method, a blower or fan pulls contaminated vapor from the venting layer and discharges it above the roof line into the atmosphere. An air discharge permit may be necessary to allow discharge to the atmosphere.

For new construction, a vent layer made from sand or pea gravel is placed below the slab foundation. Soil vapor collection piping and a common header are installed in the vent layer to direct contaminated soil vapor to a discharge stack that ends above the roofline. The blower/fan connects the common header with the discharge stack. Regulatory guidelines suggest using a sub-slab liner above the vent layer to provide added protection if the fan fails.

install piping for vapor intrusion mitigation systemFor an existing slab-on-grade building, installation of a sub-slab depressurization system entails cutting holes or trenches in the building slab, removing soil and building venting pits or trenches in the space left behind. The vent pits or trenches are arranged to provide depressurization coverage over the entire building footprint. Collection pipes are installed in the pits or trenches after which they are filled with sand or pea gravel and covered with slab material. A common header connects the collection pipes with a blower or fan. Extracted soil vapor is routed to a discharge stack.

2) Sub-Membrane Depressurization

Sub-membrane depressurization operates like the sub-slab variety but refers to creating a venting layer beneath a membrane that is installed in crawl spaces over bare earth. It can be used in new and existing buildings with crawl spaces. The membrane covers the exposed dirt surface of a crawl space, creating a venting layer between the membrane and the dirt floor. The rest of the system is similar to a sub-slab depressurization system.

The edges of the foundation and any pass-through piping need to be well sealed and the membrane should be loose enough to prevent tearing. Routine inspection of the membrane is necessary to check for the seals and membrane for damage. An air discharge permit may be necessary to allow discharge to the atmosphere. 

3) Building Overpressure

Building overpressure involves using a building’s heating, venting, and air conditioning (HVAC) systems or a new system to maintain positive pressure in a building relative to the pressure beneath the building floor. This method is typically used for commercial buildings and can be inexpensive for buildings where the HVAC system maintains a positive pressure.

 

Close

We wrapped up our conversation about active vapor intrusion mitigation (VIM) methods and turned to the question of how VIM might impact her property. I told my client that VIM at the neighbor’s property means her property won’t be exposed to soil vapor contamination from her neighbor’s property. I let her know that as long as VIM is underway, the state and local environmental health agencies will oversee the operation and that VIM will operate until cleanup goals for her neighbor’s property are reached. It was good news for my client.

We have over 35 years of experience providing solutions for environmental challenges including vapor intrusion mitigation. Can we help you? Please click the button below for a free consultation.

What is an Environmental Screening Level (ESL)?

KG well drilling 1

“I keep reading about how contamination levels are above the ESL, but all I really care about is closure. Instead, more samples and more talk about the ESL. I don’t know what this ESL is, but apparently I won’t get case closure until it is reached,” she said. “I’ve ignored it long enough - what is an ESL?”

“Good question,” I said. This prospective client came prepared with a tough question.

“ESL stands for Environmental Screening Level, '' I told her. “It’s the level of a chemical that signals there is a potential for harm to humans, water life, and animal life.” In the lull that followed, I added, “I know that’s a lot, so let’s start with where ESLs come from.”

 

Risk-Based Screening Levels (RBSLs) and Environmental Screening Levels (ESLs)

ESLs began as RBSLs

Risk-based screening levels (RBSLs) were first published by the San Francisco Bay Regional Water Quality Control Board (Board) in 2000 as a way to speed up human health and environmental risk assessments for contaminated sites.

Assessments were made easier by using a set of site conditions to estimate chemical levels (risk-based levels) that pose no harm and using them for comparison with levels at a contaminated site. If contaminant levels in soil, groundwater, or soil vapor were found to be below the RBSLs, then the site was considered low risk, otherwise, contamination levels were judged to be a potential risk.

The scope of the RBSLs expanded, and in 2003 the Board changed the name to Environmental Screening Levels (ELSs). Since then there have been several updates with the last in 2019.

The Board states that ESLs are not cleanup goals, however, the Board also states that for many sites ESLs are selected as cleanup goals. At a minimum, the Board accepts ESLs as preliminary cleanup goals.

“Okay,” my prospective client said. “What does low-threat mean?”

IMG 7612

What is a Low-Threat Environmental Screening Level (ESL)?

In the context of ESLs, low-threat typically refers to chemical concentrations in soil, groundwater, or air that do not increase the chance of developing cancer or increase harm to humans.

For chemicals that cause cancer (carcinogen), low-threat means concentrations that result in less than one chance in a million (1 in 1,000,000) of developing cancer from lifetime exposure. For non-cancer-causing chemicals, a hazard quotient is used to gauge the potential for bodily harm. The hazard quotient is a ratio that compares the estimated exposure to a chemical to the reference level of that chemical at which no harmful health effects are expected. A hazard index of 1 or more indicates the potential for harmful non-cancer health effects.

“Well, thank you,” my caller said. “ If I understand you correctly, an ESL is an okay amount of contamination that is not a threat to human health and animals. I can appreciate that.” With that, we set up a time to talk about her site and ended our phone call.

Environmental Screening Levels and Cleanup Goals

We took a look at environmental screening levels, or ESLs, published by the San Francisco Bay Regional Water Quality Control Board. We noted that while ESLs are not specifically contamination cleanup goals, they can be used as cleanup goals and oftentimes are. Do you have a question about environmental investigation and cleanup? We have over 30 years of experience providing environmental services. Give us a call at 831-475-8141 or click the button below for a free consultation.

 

Page 1 of 2