U'S' EPA Emerging Pollutants Workshop Nonylphenol and Nonylphenol Ethoxylates: Aquatic Toxicity, Est

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U.S. EPA Emerging Pollutants WorkshopNonylphenol
and Nonylphenol Ethoxylates Aquatic Toxicity,
Estrogenicity and Treatability in Wastewater
Effluent

• Charles A. Staples
• Ellen M. Mihaich
• Barbara S. Losey
• Chicago, IL
• August 11-14, 200.

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Background...

• Nonylphenol ethoxylate (NPE) surfactants are
  widely used in applications that are sent to
  sewage treatment plants when spent
• While NPEs are generally easily treatable in well
  run treatment plants, residues from
  biodegradation are often detectable in effluents
• It is of interest to examine the potential risks
  to the environment from these residues
• Risk assessment is the preferred means of
  addressing these compounds

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Background...

• Risk assessment requires
• Exposure data
• Ecotoxicity data
• The results of risk assessment are used by risk
  managers to control and manage potential unwanted
  risks
• Purpose
• Examine the ecotoxicity database, including
  endocrine-modulating effects, for the NPEs, NPEC,
  NP that are most common in effluents as shown in
  treatability studies

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Treatability studies of NPE surfactants...

• Example Canadian STPs (receive municipal and
  industrial wastes)
• STP-A
• activated sludge (2), nitrification, tertiary
  (3) treatment and UV disinfection
• removal efficiency of 97 for all species
• STP-B
• non-nitrifying activated sludge (2), chlorine
  disinfection
• removal efficiency of 86 for all species

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Treatability studies of NPE surfactants...

• Ahel and Giger (1994a,b), Lee and Peart (1998)
• main products in raw sewage are commercial NPE
• main components in final effluents were NPEC with
  some NPE1,2, and traces of NP
• Monitoring studies
• 30 Rivers Study
• NP NPE1,2 0.1 µg/L, NPE3-16 2 µg/L
• USGS National Reconnaissance Survey
• NP, NPE1,2 medians 0.8 to 1.0 µg/L
• Risk assessments of NPE residues from STPs in
  surface water should encompass
• NPEs, NPEC, NP

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Chronic aquatic toxicity of NP...

• Critical review of chronic aquatic toxicity data
  for NP and NPE
• Dozens of studies, endpoints, LOEC, NOEC
• Survival, growth, reproduction
• Manuscript to be submitted to International
  Journal of Human and Ecological Risk Assessment
• SSD analysis shows that the data support the
  draft USEPA WQC for NP (5.9 ?g/L)

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Chronic aquatic toxicity of NP...

• All studies were subject to a quality review
• 1. Thorough description of the experimental
  design, including test material identification
  and description, exposure regime and
  replication
• 2. Analytical confirmation of test
  concentrations
• 3. Description of all ecologically relevant
  endpoints and all supplemental secondary
  biochemical and morphological information
  collected, including a full description of how
  they are measured

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Chronic aquatic toxicity of NP...

• All studies were subject to a quality review
• 4. Use of test procedures that are based, at
  least generally, on internationally accepted
  procedures and practices, including both draft
  and final methods
• 5. Clear linkage of reported findings with the
  exact experimental design, and,
• 6. Sufficient reporting of results, including
  system performance, adequacy of control
  performance, toxicity results, and statistical
  methods employed to ascertain how the data
  support the conclusions.

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Survival ChV x Growth ChV ? Reproductive ChV
Figure 1. Chronic values (ChV) for survival (),
growth (x) and reproduction (?) for fish (F),
aquatic invertebrates (INV), and algae (ALG) by
NPEx.
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Determination of in vivo endocrine effects in
fish from NPE and biodegradation metabolites

• Gordon Balch and Chris Metcalfe (Trent
  University, Peterborough, ON, Canada), February
  2003
• Exposed medaka fish to NP, NPE1, NPE4, NPE9,
  NPEC1 from 1 to 100 days post-hatch
• Endpoints
• sex ratio
• secondary sex characteristics
• liver VTG
• testis-ova

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Results...
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Study Results...
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Conclusions from medaka study...

• NP induced gonadal intersex and mixed secondary
  characteristics in male medaka at 30 and 100 ?g/L
• Mixed secondary sex characteristics were induced
  in males at 300 ?g/L NPE1
• No evidence of estrogenicity with NPE4, NPE9 or
  NPEC up to 1000 or 3000 ?g/L
• No effect on sex ratio for any compound

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Summary and Conclusions...

• Ecotoxicity studies show increasing toxicity with
  decreasing ethoxylation
• Ecotoxicity studies of NPECs show them to be
  relatively non-toxic
• Only NP showed estrogenic potential in a
  long-term developmental study with medaka
• Thus, the available database of conventional
  chronic studies should be adequate to address the
  ecotoxicity of the various biodegradation
  intermediates of NPE surfactants

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Summary and Conclusions...

• Treatability studies show that well run STPs are
  effective at removing NPE surfactants, but
  residues do enter receiving waters
• Risk assessments of surface waters receiving STP
  effluents should address all biodegradation
  intermediates
• Risk management to reduce risk from natural
  hormones in human waste simultaneously addresses
  NPE, NP, NPEC
• Risk management to reduce risk from industrial
  sources should include Best Management Practices