Biological Fate of Estrogenic Compounds Associated with Sewage Treatment: A Review
Gregory Sayles, U.S. EPA
Tamara Marsh, Elmhurst College, IL

Purpose
.. Give you current thinking on fate of EDCs in sewage treatment systems
– Available data
– Qualitative discussion

Most Prevalent Estrogenic Chemicals found in STP Effluent
.. Alkylphenolic compounds
– Biodegradation products from APE surfactants
. Nonylphenolics
. Octylphenolics
..Steroid hormones
– Natural (estradiol, estrone, estriol)
– Synthetic (ethinyl estradiol)

Typical Large STP
Chart Contact Greg Sayles at sayles.gregory@epa.gov or (513) 569-7607

STPs Designed for…
.. BOD removal
.. Suspended solids removal
.. pH neutralization
..N, P removal
.. Pathogen removal

Current Knowledge Limited
.. For nonylphenolics:
• Parent NPE are a distribution of EO units
• Greater than 20 isomers of the nonyl group
• Analytical standards for NPE metabolites difficult to obtain
.. For steroids and nonylphenolics:
• Analytical methods not standardized
• Low detection limits needed (ng/l)
.. Few biodegradation studies published

NPEs - STP Influent / Raw Sewage
.. ~ 500 million pounds used per year in U.S.
.. Institutional: laundry detergents, janitorial and vehicle cleaners
.. Household: cleaners and personal care products
.. Industrial: plastics, textiles and pulp and paper processing, ag chemicals
.. Total nonylphenolics 500 to 2500 ug/l
.. Total estrogenic products 1 to 50 ug/l

Biological Transformation of APEs 
Aerobic
Parent surfactant “nonylphenol polyethoxylate”
Chart Contact Greg Sayles at sayles.gregory@epa.gov or (513) 569-7607

Biological Transformation of APEs
Aerobic
Chart Contact Greg Sayles at sayles.gregory@epa.gov or (513) 569-7607

Biological Transformation of APEs
Aerobic
Chart Contact Greg Sayles at sayles.gregory@epa.gov or (513) 569-7607

Biological Transformation of APEs
Aerobic
Chart Contact Greg Sayles at sayles.gregory@epa.gov or (513) 569-7607

Biological Transformation of APEs
Aerobic
Chart Contact Greg Sayles at sayles.gregory@epa.gov or (513) 569-7607

Biological Transformation of APEs
Anaerobic
Chart Contact Greg Sayles at sayles.gregory@epa.gov or (513) 569-7607

Nonylphenolic STP Balance
Rome, Italy (Di Corcia, 2000)
Chart Contact Greg Sayles at sayles.gregory@epa.gov or (513) 569-7607

NPE Metabolites Partition to Sludge
EDC: 
Log (Kow): 
EDC: NP Log (Kow): 4.5
EDC: NP1E Log (Kow): O4.2
EDC: NP2E Log (Kow): O4.2
EDC: CNP1EC Log (Kow): << 4

Likely Fate in STP
Chart Contact Greg Sayles at sayles.gregory@epa.gov or (513) 569-7607

Effluent Fate
.. Expect alkyphenolics in
- Surface water (up to 20 ug/l)
- Sludges (up to 50 mg/kg)
- Sediments (up to 4000 mg/kg)

Influent Estrogens
estrone
ethinyl estradiol
estriol
estradiol

Amount of Estrogens Excreted
Chart Contact Greg Sayles at sayles.gregory@epa.gov or (513) 569-7607

STP Influent - Raw Sewage
.. Estradiol ND – 50 ng/l
.. Estriol, estrone ND – 100 ng/l
.. Ethinyl estradiol ND – 10 ng/l

Estrogens in Activated Sludge
From 6 STPs in Tennessee (Layton, 2000)
Chart Contact Greg Sayles at sayles.gregory@epa.gov or (513) 569-7607

Example STP Removal – Rome Italy
Chart Contact Greg Sayles at sayles.gregory@epa.gov or (513) 569-7607

Biodegradation of Estrogens
.. Aerobic
- All biodegradable, ethinyl slowest
- Nitrification may increase rate
.. Anaerobic
- Little known
- Little biodegradation expected

Partition to Sludge, Sediments?
EDC: Ethinyl estradiol (Kow): 4.2
EDC: Estradiol (Kow): 3.9
EDC: Estrone (Kow): 3.4
EDC: Estriol (Kow): 2.8
No sludge, sediments field data to date

Overall Impact of Various EDCs in 
STPs (Johnson, 2001)
Chemical: 
Estradiol Equivalent (in vivo studies): 
Level of Concern: 

Chemical: Ethinyl estradiol, Estradiol Equivalent (in vivo studies): 12, Level of Concern: High
Chemical: Nonyl-, octyl-phenol2, Estradiol Equivalent (in vivo studies): –20, Level of Concern: Moderate
Chemical: Estrone, Estradiol Equivalent (in vivo studies): 2.5, Level of Concern: Moderate
Chemical: Estradio,l Estradiol Equivalent (in vivo studies): 1.0, Level of Concern: Moderate
Chemical: Estriol, Estradiol Equivalent (in vivo studies): 0.02, Level of Concern: Lowest
Chemical: APEs, APECs, CAPEs, Estradiol Equivalent (in vivo studies):?, Level of Concern: Low?

Summary
.. Current limited data 
– Aerobic biodegradation produces estrogenic alkylphenolics in STPs
– No evidence of destruction of alkylphenolics in STPs
– Steroid hormones are aerobically biodegradable
. Retention time in STP appears to be short
– Sludge will accumulate low MW alkylphenolics and hormones
.. Need detailed studies of EDC fate within the STP
.. Are other sewage treatment systems removing EDCs?
– Septic systems?
– Small community treatment, constructed wetlands?

Bibliography available upon request
Contact Greg Sayles at sayles.gregory@epa.gov or (513) 569-7607