Emerging Contaminants – a Primer Bob Kennedy CTO newterra
We live in a very complex world, with hundreds if not thousands of new products and compounds that enter the market each year for either personal, commercial, military or industrial use. In total they represent millions of tons of manmade substances that in some form may make their way into the world’s most precious resource … our water. The impact of many of those products and substances are only now being understood by scientists and the medical community around the world.
In fact, testing for many of these compounds is not required to certify water safe for drinking, nor are most of them on the regulated list for drinking water standards.
What are Emerging Contaminants Substances of emerging concern or emerging knowledge … New information is being published relating to toxicity of a well known substance. New observations in the environment that may be attributable to an effluent or substance. New chemicals on the market in consumer / commercial / industrial products/processes have known or suspected adverse effects. New routes of exposure in the food web, or a new pathway to humans that is alarming.
Where are Emerging Contaminants Wastewater effluents Industrial contamination of soil/groundwater Landfill leachates Airport fire fighting training facilities
They are in our food, products, consumer goods, water
Why are they important now? Just beginning to understand effects on the ecosystem and humans Were unable to measure or quantify before at ppb or ppt levels Emerging from contained areas (landfills, airports etc) and into groundwater sources
Emerging Contaminants Pharmaceuticals
Endocrine Disruptors (EDC)
Personal Care Product (PPCP)
Engineered Nano Particles (ENP) and Microplastics
Pharmaceuticals Human and veterinary drugs Dietary supplements
Pharmaceuticals Excretion by humans and domestic animals Disposal of unneeded or expired PPCPs by flushing them down a toilet or drain Discharge from municipal sewage systems or private septic systems. Municipal wastewater treatment plants generally don’t treat for the compounds found in PPCPs. They can be spread to farmers fields via manure or human waste spreading, then washed into streams or seep into the aquafer
Cosmetics Some of the ingredients in beauty products just aren’t that pretty. One in eight of the 82,000 ingredients used in personal care products are industrial chemicals: carcinogens pesticides reproductive toxins hormone disruptors. Compounds from cosmetics, lotions and sunscreen enter surface water bodies through direct contact or through discharge from STP
Cosmetics BHA and BHT Coal tar dyes DEA-related ingredients Dibutyl phthalate Formaldehyde-releasing preservatives Parabens Parfum (a.k.a. fragrance) PEG compounds Petrolatum Siloxanes Triclosan
Cosmetics – emerging Siloxanes Siloxanes, also known as silicones, are manmade saturated silicone-oxygen hydrides and are listed in many countries as hormone disruptors Siloxanes are amazing substances and are used for their hydrophobicity, low thermal conductivity, and high flexibility Siloxanes (since 1940) are used in many cosmetic, electronic, household, fuel, automotive and medical device products. Exposure occurs from personal products, water and food ingestion, wastewater, industrial processes, and sewage sludge
Nanomaterials – the next miracle product Very small particles engineered for special functions including catalytic behavior, high strength, thermal and electrical conductivity etc. Biomedical, solar panels, water treatment etc
Emerging occupational hazard typically through inhalation Regulation not keeping up
Microplastics Microplastics are everywhere In the air In the soil In the water In our food Even in your bottled water Tiny shards of plastic less than 5,000 microns in length
EDC’s (Endocrine Disruptors) EDC’s are chemicals that can interfere with the endocrine or hormone systems in the body.
Any system in the body can be affected. Typical effects are tumors, birth defects, lower fertility, development disorders and immune systems
Shortlist
Contaminant
Where
Permethrin
Pesticide formulations, bulk storage, spills Neurotoxic to fish
1,4 Dioxane
Co-solvent, replaces chlorinated solvents Food, cosmetics, children’s products Landfills, very soluable in gw
PFOS, PFOA (perfluorinated)
Fire fighting foam, retardants Adhesives, cosmetics, consumer products Soluble in gw, sticky with soil, found in leachate Endocrine disruptor
Contaminant
Where
Sulfolane and DIPA
Natural gas and LNG Highly soluble in gw
Methylnaphthalene (alkylated PAH)
Oil and gas activities, drilling, production, processing, retail and storage
Contaminant
Where
EE2 (estrogen, birth control)
Closure of Sewage Lagoons, Sewage Plant effluents. Fish population collapse in lakes and rivers at 0.005 ppb
Nonylphenol and ethoxylates (detergents and surfactants)
STP effluents, pesticides, pulp and paper, textiles, paint, fracking Endocrine distruptor
Triclosan and other antimicrobials
Skin exposure, thyroid impacts, plant toxicity, breakdown to dioxins
Chlorinated Alkanes (paraffins)
Lubricants, flame retardant, landfill, industrial sites
Contaminant
Where
Siloxanes
Personal products, food, wastewater, sewage sludge, car wax, fuel additive, landfill Endocrine disruptor
Pharmaceuticals
Landfill leachate, STP, sludge May effects on aquatic environment, drinking water
Microplastics
Face washes, toothpaste, laundry water Accumulate in organisms at all trophic levels – filter feeders, plankton and up Bind organic contaminants, transport toxins through ingestion
Contaminant
Where
Nanomaterials (nanosilver, nanocarbon)
3 dimensions < 100 nm Health and fitness products Antimicrobial (socks, bandages, textiles) Groundwater, STP, Leachate
PBDE’s (Polybrominated diphenyl ethers)
Landfill leachate, electrical and plastics manufacturing
Winners
Winners Biggest short term impact on contaminated site work
PFAS
1,4-dioxane
Used to make clothes water and stain resistant. Means take a long time to break down in the environment Easily glide through human blood Catches and blocks growth and reproductive hormones Nests in the human liver
Health Canada PFAS Screening Values
Treatment Objectives – 70 PPT (part per trillion) 70 ppt is equivalent to 70 drops of water diluted into 20, two-meter-deep Olympic-size swimming pools (50,000 m3)
Treatment Objectives – 70 PPT (part per trillion) 70 drops of ink dropped into Niagara falls over a 20 second period
Treatment Challenges - PFAS Broad mixture - Wide range of properties, long and short chain - Hydrophobic and electrostatic effects Low volatility High Solubility - long plumes Treatment requirements to very low concentrations
Treatment Options Excavation and Incineration - expensive - not suitable for on site treatment
Immobilization/Stabilization - several approaches that can be successful to contain plumes - powdered reagents and modified clay - liquid carbon products
Treatment Options Bioremediation - aerobic not effective - anaerobic has some effect but may produce toxic intermediates
Membrane Filtration (RO and Nanofiltration) - generally rejects 99% of PFOS, but waste stream must be dealt with Adsorption - Activated carbon
Treatment Options Ion Exchange - Resins - Zeolites - Biomaterials Chemical Treatment - Chemical oxidation - Electrochemical - Plasma
Treatment Options - Focus Carbon Adsorption
Ion Exchange
Typical pump and treat solutions
Some are treating potable well water
Treatment Options - GAC •
may have issues if lots of organics
•
Pre treatment for iron, manganese or hardness may be required
•
Disposal by incineration or reactivation (reduce long term liability)
• Performance varies with source material and activation method • Can be an expensive option, but works
Treatment Options – Ion Exchange •
Resins exchange ions, can remove both long and short chain PFAS
• Typically contact time required is less than carbon, so smaller footprint • Anionic resins successfully used • Single use systems resin is used once then incinerated • Regeneration systems can create hazardous waste stream, although techniques exist to regenerate with no waste products
Treatment Options – 1,4 Dioxane No Federal guidelines in Canada or US 1,4 Dioxane miscible in water
Typical treatment will be ex-situ with advanced oxidation Biological treatment may also be possible
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