Dealing with Emerging Contaminants
Mar 14, 2017 -
What are Emerging Contaminants?
In the environmental remediation industry, we often talk about “emerging contaminants,” but what are they actually? The USGS defines emerging contaminants as any “synthetic or naturally occurring chemical or microorganism that is not commonly monitored in the environment but has the potential to enter the environment and cause known or suspected adverse ecological and/or human health effects.”
In other words, emerging contaminants are not actually emerging from anywhere - they’re here, measurably present in the environment now. Instead, it’s our awareness of these specific chemicals and the harm they can cause that is emerging.
Whether you know it or not, most of us rely on chemicals throughout our daily lives. In fact, over 80,000 different chemicals are produced and used in the United States alone. Most of these are harmless, but as our society learns more about the things that we manufacture and our impact on the environment, there is growing understanding that these harmful elements need to be properly dealt with. That’s where professionals with proven experience and expertise in environmental remediation - like Cascade Environmental - come in.
Different Types of Emerging Contaminants
The main categories of emerging contaminants are industrial chemicals, pesticides, pharmaceuticals, and personal care products - which includes a number of hormones.
A unique type of emerging contaminant that is currently causing a lot of concern is plastic-based microfibers that result from laundering of polypropylene and other synthetic fabrics. These tiny bits of plastic fiber enter sewer systems, and they can not be removed or treated in wastewater treatment plants prior to its discharge into a larger bodies of water. These bodies of water often serve as water supplies for large populations.
Aside from the health problems they can cause on their own, such as interrupting endocrine systems, these microfibers also accumulate contaminants such as PCBs (Polychlorinated biphenyls) and may facilitate further accumulation of contaminants in both animals and humans.
Microfibers are mainly restricted to surface water, and they’re unlikely to be of significant concern in groundwater.
Pharmaceuticals and Personal Care Products
Like microfibers, many chemicals in pharmaceuticals and personal care products are not treated effectively in wastewater treatment plants and are often discharged to surface water bodies. However, they are distinguished from microfibers in that they can and often are introduced to groundwater through in-ground septic systems, infiltration of surface water, leaking sewer lines, and land application of WWTP sludge.
Unfortunately, the chemicals from pharmaceuticals and personal care products are everywhere. These contaminants are so ubiquitous that artificial sweeteners and certain pharmaceuticals are used as ambient tracers in groundwater studies of wastewater impacts.
PFAS, or poly and perfluorinated alkyl substances, are a particularly persistent kind of emerging contaminant, and one that’s also finding it’s way into drinking water. Investigation and remediation of PFAS is growing rapidly with no signs of slowing down.
The two fluorinated compounds that have been driving much of the interest, and the only two compounds for which the EPA has issued health advisory levels, are perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA).
Other familiar “emerging contaminants” are additives in commonly used products such as the introduction of MTBE In gasoline years ago, and the addition of 1,4-dioxane to chlorinated solvents used in degreasing operations.
Where do PFAS come from?
Fluoropolymers are widely used in the aerospace, automotive, telecommunications, electronics and consumer products industries.
They are also commonly used in:
- textile and carpet coatings
- paper surface treatment
- non-stick cookware
- linings in food packaging
- wire and cable coatings
- hoses and tubing products
- ink jet ink
- mist suppressants for metal plating
- construction materials
- floor polishes
PFAS are also key components of Aqueous Film Forming Foams (AFFF) which, from 1996 to 2002, were widely used in firefighting in aviation, oil refineries, and petrochemical plants – many different places. The federal government is the largest user of AFFF, particularly in military firefighting training and actual use.
In addition to direct releases from manufacturing facilities and firefighting sites, PFAS can also be introduced to surface water bodies by wastewater treatment plant discharges, as the plants are not designed to treat for these chemicals. Sanitary landfills leach PFAS and treatment plant sludges if applied to land, will also spread PFAS. A source of widespread low level PFAS contamination is airborne deposition via rain or snowfall.
PFAS are particularly persistent in the environment, and take special equipment and analyses to be successfully remediated. The carbon-fluorine bond is extremely strong, contributing to the persistence of PFOS and PFOA in the environment.These compounds are known as C8 compounds and they do not degrade appreciably or volatilize readily.
Health Issues Stemming from PFAS
Health problems stemming from these compounds were first publicly recognized as a result of a lawsuit filed by a dairy farmer in West Virginia against DuPont for poisoning his cattle with discharge to surface water from a chemical landfill. The landfill, which was adjacent to this man’s farm, resulted in dead cattle.
PFOS and PFOA, like other emerging contaminants, have been found not to be metabolized by humans and to bioaccumulate in humans and other animals. The half-life of PFOS in humans is 5.4 years while that for PFOA is 2.3 years.
Studies suggest that PFOA exposure is associated with higher cholesterol, increased liver enzymes and/or decreased bilirubin, chronic kidney disease and early menopause, obesity in female children at 20 years of age, and Attention Deficit Hyperactivity Disorders. High blood levels of PFOA are associated with kidney and testicular tumors.
In 2016 EPA issued a Health Advisory level of 70 parts per trillion (ppt) in water. Recently laboratory methods have been developed to achieve detection limits for these compounds are in the single digit parts per trillion, allowing for meaningful monitoring and investigation of these compounds in the environment.
Emerging Contaminants in Our Drinking Water
As required by the Safe Drinking Water Act (SDWA) of 1974, the US EPA maintains a list, called the Contaminant Candidate List. This list is updated every five years, and it’s used to prioritize regulatory decision making.
The EPA recently published its Third Unregulated Contaminant Monitoring Rule (UCMR 3) data summary which includes 30 contaminants (7 VOCs; 6 metals; 1,4-dioxane; 1 oxyhalide anion (chlorate); 6 perfluorinated compounds; 7 hormones; and 2 viruses) and evaluates how widespread these contaminants are in public water supplies as these are contaminants of emerging concern. Here’s what they found -
- The most widespread chemical was chlorate which was measured above reference concentration in 38% of the public water supplies sampled.
- 1,4-dioxane was found above reference concentration in 7% of public water supplies.
- Perfluorinated compounds PFOS and PFOA were present in 0.9% and 0.3% of public water supplies respectively.
- Chromium was found in only 0.02% of PWS above reference standard.
In many cases the toxicity of the emerging contaminants is not well understood. This is largely due to the existing analytical methods which are inadequate to quantify the contaminants at their specified levels of concern. When it comes to contamination in water it is axiomatic that you only find what you are looking for. Most routine laboratory analyses only cover a very small number of compounds among those that are widely present in the environment. We simply don’t know what chemicals are present in our water most of the time, but that’s where Cascade Technical Services comes in.
Environmental Remediation with Cascade
As the nation's largest provider of environmental drilling and environmental remediation, Cascade is leading the charge in addressing emerging contaminants like PFAS. Aside from our national presence, and the breadth of our experience and expertise with site characterization and remediation, we now offer our PFAS MobiLab program, which allows for rapid and accurate on-site analysis for PFAS. The benefits of a MobiLab include: 1); having a lab at your job site and dedicated to your project. Rapid turnaround (near real time) allows site investigators to use the dynamic work strategies that are at the heart of the Triad Approach for reducing uncertainty and cost while increasing the likelihood of successful remediation. 2) since MobiLab is charged by the day, a larger number of samples results in a lower cost per sample relative to quick turnaround analyses from conventional fixed labs, in turn allowing cost effective higher resolution site characterization. 3) Since PFAS are so ubiquitous and detection limits are so low, it is relatively easy to encounter cross contamination during a site investigation. Having a laboratory onsite allows for rapid isolation and elimination of any such sources of cross contamination. 4) Field sampling teams can devote their entire day to sampling rather than having to spend up to 2 hours per day packing and shipping samples and managing the attendant paperwork. This means more productive field campaigns.