Olya Keen, PhD, PE Assistant Professor

University of North Carolina - Charlotte

Emerging contaminants in the environment: Sources, fate and treatment

Overview

What are emerging contaminants?

How do they get into the environment?

What do we do to treat them?

Chemical treatment processes and transformation products

Trace Organic Contaminants Other terms: Micropollutants Emerging contaminants Contaminants of emerging concern

Subclasses: Pharmaceuticals and Personal Care Products (PPCPs) Pharmaceuticals

Antibiotics Hormones Psychoactive chemicals

Personal care products (fragrances, surfactants, insect repellants, etc.)

Industrial chemicals (dioxins, perfluorinated chemicals, flame retardants) Miscellaneous products of human activity (sugar substitutes, caffeine, nicotine, illicit drugs)

Medication

Personal care

products

IndustrialChemicals

Endo

crin

e di

srup

tors

Pers

isten

t, bi

oacc

umul

ativ

eSources: Pharmaceuticals

Medication to WWTP

Medication to DWTP

Sources: Personal Care Products

Personal care

products

Main known offenders:- 4-nonylphenol ethoxylates- Triclosan/triclocarban- Insect repellants- Nanomaterials (organic and

inorganic)- Microbeads

Currently banned

Sources: Industrial Chemicals

IndustrialChemicals

Main known offenders:- PBDE (flame retardant)- PFOA/PFOS (non-stick coating, etc.)- Bisphenol A (plastics)- 1,4-dioxane (industrial chemical)

Plus “regrettable substitutions”

What are the levels? ng/L to low μg/L (one in a trillion to one in a billion)

2,500,000 L

1 μg/L × 2,500,000 L = 2,500,000 μg = 2.5 g

What’s the big deal? Environmental effects Endocrine disruption Toxicity Other things the importance of which we still don’t fully understand Bioaccumulation Psychoactive drug effects

Human health effects Antibiotic resistance Other effects that may be overlooked Effects of drug mixtures Effects of chronic exposures Endocrine disruption?

Endocrine disruption

Vajda et al. 2008

Vajda et al. 2008

Barber et al. 2012

What’s the big deal? Environmental effects Endocrine disruption Toxicity Other things the importance of which we still don’t fully understand Bioaccumulation Psychoactive drug effects

Human health effects Antibiotic resistance Other effects that may be overlooked Effects of drug mixtures Effects of chronic exposures Endocrine disruption?

1 µg/L

1 µg/L

Upper range of environmental concentrations

What’s the big deal? Environmental effects Endocrine disruption Toxicity Other things the importance of which we still don’t fully understand Bioaccumulation Psychoactive drug effects

Human health effects Antibiotic resistance Other effects that may be overlooked Effects of drug mixtures Effects of chronic exposures Endocrine disruption?

Bioaccumulation

Wide range of Kow values

Fragrances

Detergent components (including nonylphenol!)

Fecal sterols

Flame retardant

Kinney et al. 2008

Bioaccumulation

200 ng carbamazepine per cucumber grown hydroponically in reclaimed water

500,000 cucumbers or 100 ton

Shenker et al. 2011

Biomagnification Between 2000 and 2003, high annual adult and subadult vulture mortality (5-86%)

and resulting population declines (34-95%) in Pakistan and India

Oaks and Gilbert 2004

What’s the big deal? Environmental effects Endocrine disruption Toxicity Other things the importance of which we still don’t fully understand Bioaccumulation Psychoactive drug effects

Human health effects Antibiotic resistance Other effects that may be overlooked Effects of drug mixtures Effects of chronic exposures Endocrine disruption?

Painter et al 2009

Psychoactive substances

What’s the big deal? Environmental effects Endocrine disruption Toxicity Other things the importance of which we still don’t fully understand Bioaccumulation Psychoactive drug effects

Human health effects Antibiotic resistance Other effects that may be overlooked Effects of drug mixtures Effects of chronic exposures Endocrine disruption?

Antibiotic resistance

Trace levels of antibiotics select for the most resistant organisms

Horizontal gene transfer between species in densely populated biological processes

Gene transfer can happen even from dead bacteria after disinfection

Once the water is released into the environment, the contact between the environmental microorganisms and antibiotics continues

What’s the big deal? Environmental effects Endocrine disruption Toxicity Other things the importance of which we still don’t fully understand Bioaccumulation Psychoactive drug effects

Human health effects Antibiotic resistance Other effects that may be overlooked Effects of drug mixtures Effects of chronic exposures Endocrine disruption?

Things we don’t know

Effects of drug mixtures

Effects of chronic exposures

Human endocrine disruption? Birth control pills contain 10 - 30 μg of 17α-ethynil estradiol (EE2) in combination

with other hormones 11 of 70 US streams surveyed had detectable levels of EE2 with 0.073 μg/L average and 0.831 μg/L max (Kolpin et al. 2002)

400 L of water at environmental concentrations contain a therapeutic dose

Role of the wastewater and water treatment plants Some of the release of emerging contaminants can be prevented by Regulation on medication disposal More thoughtful formulation of consumer products More restrictions on industrial chemicals

Some release is not preventable Household practices Undigested medication Quality of life

The only line of defense Water/wastewater treatment

Medication to WWTP

Basics of wastewater treatment

Remove large objects and solids

Biological treatment

Disinfection Chlorine Ultraviolet (UV)

Attenuation of contaminants in biological treatment

Biological processes Not effective against antibiotics Limited effectiveness for synthetic hormones

(requires specific treatment conditions) Some other highly recalcitrant compounds: Carbamazepine

X-ray contrast media

Sucralose

Good biological removal of NSAID (ibuprofen, acetaminophen), natural hormones, earlier generation of meds (aspirin, penicillin, etc.)

Joss et al. 2005

Joss et al. 2006

Attenuation of contaminants in conventional treatment

Adsorption onto sludge (fragrances)

Other things that adsorb onto sludge Steroids Flame retardants Surfactant components (nonylphenol ethoxylates) Perfluorinated compounds

Joss et al. 2005

Chemical treatment processes (what I study)

Conventionally used disinfection UV Chlorine Ozone (not very common in the US)

Advanced processes (used in water reuse applications) Advanced oxidation processes Memrane filtration (reverse osmosis) Activated carbon

Selective effectiveness

Expensive

UV

Kim et al. 2009

UV

0

0.2

0.4

0.6

0.8

1

1.2

ERM DCL CLM PCG CPF TMP

Frac

tion

rem

aini

ng

After 2000 mJ/cm2

MPUV

LPUV

Keen and Linden 2013

Antibiotics:ERM = erythromycinDCL = doxycyclineCLM = clindamycinPCG = penicillin GCPF = ciprofloxacinTMP = trimethoprim

Chlorine and chloramine

Pinkston and Sedlak, 2004

Chlorination of antibiotics Fluoroquinolones formed active products Doxycycline in clean water only Sulfamethoxazole/trimethoprim did not form active products

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0.2

0.4

0.6

0.8

1

1.2

0 0.5 1 5 10 30 60 120Nor

mal

ized

con

cent

ratio

n or

PEQ

Chlorine Exposure time, min

Ciprofloxacin PEQ

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0.2

0.4

0.6

0.8

1

1.2

0 0.5 1 5 10 30 60 120Nor

mal

ized

con

cent

ratio

n or

PEQ

Chlorine exposure time, min

Ciprofloxacin PEQ

Pure water Treated wastewater

Advanced treatment processes Advanced oxidation

Membrane filtration (reverse osmosis)

Activated carbon

Variable efficiency depending on contaminant propertiesRemoves everything except the smallest molecules

Keen, O.S. and Linden, K.G. (2013) Degradation of antibiotic activity during UV/H2O2 advanced oxidation and photolysis in wastewater effluent. Environmental Science and Technology 47(22), 13020-13030

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0.4

0.6

0.8

1

1.2

1.4

00.20.40.60.81

Pote

ncy

equi

vale

nt

Normalized concentration of the parent antibiotic

Erythromycin

Doxycycline

1:1 line

Transformation product management

Bar screen

Pump

Equalization tank

Solids digester

Advanced oxidation

Final dewatering

Biological treatment(MBR-like)

Outlook for the future Still a lot to learn

Some level of regulation is necessary and likely (but probably not in the immediate future, based on the state of knowledge)

Prevention may not be effective, so treatment works, esp. wastewater, may need to upgrade treatment

Questions?

okeen@uncc.edu