Over many years human activities have produced large quantities of waste materials and by-products across the United States. Unfortunately, many of these manmade waste materials have been carelessly used, disposed of, or stored on properties where they seep into the underlying soil and groundwater.
Contaminated groundwater and soil are hazardous to public health. Drinking contaminated groundwater can cause diseases such as hepatitis and dysentery and can also cause certain types of cancer. Toxins leaching into well waters can also cause poisoning.
Soil contaminants from polluted land can cause many types of health issues ranging from minor symptoms such as skin irritation or nausea and more serious illnesses like cancer or even death. They can even contaminate water supplies – all reasons why remediation is essential.
Table of Contents
Soil and Groundwater Remediation: What Is It?
Remediation is the process of removing contaminants from soil and water sites that have been polluted by industrial, manufacturing, mining, or commercial activities, thereby removing or reducing our exposure to the contaminants. The end goal is to eliminate the contamination sources and protect people and the environment against potentially harmful pollutants.
Soil Remediation
Soil remediation is the method of purifying and revitalizing contaminated soil. Untreated, soil contamination presents many risks through direct contact, ingestion (eating or drinking), or when introduced into the food supply chain. Soil remediation will remove contaminants to protect both the people’s health and the environment.
Remediation treats soil contaminants such as heavy metals, petroleum hydrocarbons, and pesticides. It may also be used at sites where toxic materials have been deposited as a result of a natural disaster. These processes may be physical, chemical, thermal, or biological, depending on the contaminant that is being remediated. There are three main soil remediation processes. They include soil washing, bioremediation, and thermal desorption.
- Soil washing is a water-based process that uses surfactants and water to remove undesirable contaminants from the soil. The process involves either dissolving or suspending pollutants in the wash solution (which is later treated by conventional wastewater treatment methods) or by concentrating them into a smaller volume of soil through simple particle size separation techniques (like those used in sand and gravel operations).
- Bioremediation uses living microorganisms, such as bacteria and fungi, to reduce pollution through the biological degradation of pollutants into non-toxic substances. This can involve either aerobic or anaerobic microorganisms that often use this breakdown as an energy source. Bioremediation typically requires fewer resources and less energy than other technologies and does not accumulate hazardous by-products as waste. Bioremediation has technical and cost advantages, although it can often take more time to complete than traditional methods.
- Thermal desorption, often used for hydrocarbon contamination, uses heat to increase the volatility of contaminants so that they can be separated from the solid material. The contaminants are then either collected or destroyed. A benefit of this process is that the soil can be reused after it is cleaned and purified, eliminating the need to ship it to a landfill.
Groundwater Remediation
Groundwater is water that is underground and found in large aquifers or water that is contained in the subsurface layer of rock and soil. Some of the most common contaminants found in groundwater include arsenic, iron, chromium, selenium, and fluoride.
Groundwater deterioration that originates from the land surface(underground) could be due to the infiltration of contaminated surface water, wastes from land and water disposal, fertilizers and pesticides, accidental spills, and other airborne particulate matters.
Deterioration originating from above the water table (near the surface) may be caused by septic tanks, surface impoundments, landfills, leakage from underground pipes and storage tanks, sumps, and even graveyards.
There are various methods used in groundwater remediation. Some of them include:
- Pumping systems
- Interceptor systems
- In situ treatments
- Biodegradation
- Groundwater barrier systems
Why Is Remediation Important?
Depending on the type of soil and water contaminants and how prevalent they are, they can be fatal for us, plant life, and wildlife. Contaminated soil and water can affect animals when they drink polluted water or eat contaminated plants. Soil contamination can destroy entire ecosystems through the loss of wildlife habitat. By remediating soil and water contamination, we can improve our health and our environment.
What Causes Contamination?
Contamination can be caused by the application of chemicals like fertilizer and pesticides, radiation, chemical spills from industrial plants, stormwater runoff, or leaks from underground storage tanks and landfills. Some sites have been polluted by manufacturing, mining, or commercial activities.
What Are Groundwater and Soil Assessments?
Soil and groundwater assessments focus on collecting samples for analysis based on a known or suspected environmental condition. The collection of the samples may include the installation of soil borings and groundwater monitoring wells.
Regulations
As public concern about polluted soil and groundwater in the United States grew in the past few decades, it promoted the development of government programs and regulations aimed at controlling and remediating the contamination.
Below is a summary of some of the regulations that govern the safe use, release, and cleanup of contaminants.
Superfund
Superfund is the common name for the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) which was passed in 1980 to deal with abandoned hazardous waste sites. Through Superfund, the EPA finds the companies who are responsible for the contamination—known as potentially responsible parties (PRP). It requires them to clean up polluted soil or pay for the cost of cleanup.
Ground Water Rule
EPA issued the Ground Water Rule (GWR) in 2006 to improve drinking water quality and provide protection from disease-causing microorganisms. Water systems that have groundwater sources may be susceptible to fecal contamination, which can contain disease-causing pathogens. The purpose of the GWR is to reduce disease incidence associated with harmful microorganisms in drinking water. The GWR applies to public water systems that use groundwater as a source of drinking water.
RCRA
The Resource Conservation and Recovery Act(RCRA) regulates the storage, transportation, treatment, and disposal of solid and hazardous wastes to prevent contaminants from leaching into groundwater.
FIFRA
The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) authorizes the EPA to control the availability of pesticides that have the ability to leach into groundwater. FIFRA’s objective is to ensure that, when applied as instructed, pesticides will not generally cause unreasonable risks to human health or the environment.
TSCA
The Toxic Substances Control Act (TSCA) authorizes EPA to control the manufacture, use, storage, distribution, or disposal of toxic chemicals that have the potential to leach into groundwater or contaminate the soil.
CWA
The Clean Water Act (CWA) authorizes the development of surface water protection strategies and authorizes several programs to prevent water pollution from a variety of potential sources.
Site Remediation Specialists
Site remediation specialists focus on cleaning up toxic sites and removing contaminants from soil and groundwater. They commonly work with a team of environmental geologists, hydrologists, and toxicologists and investigate which methods and technologies will work best for a specific site.
Specialists will develop remediation measures which may include removing the contamination source. They will test samples, develop a program to assess soil or groundwater quality, and eventually implement long-term abatement measures with the aim of returning the site to its former state.
Need assistance with soil and groundwater contamination? Contact AOTC today to discuss how our trusted environmental remediation services can rid your site of toxins while saving you time and money.