ATTACHMENT B

Attachment 

Response to Comments from APERC

The Alkylphenols and Ethoxylates Research Council (APERC) comments were, on the 

whole, critical of our recommendation and of Southern California Coastal Water 

Research Project’s (SCCWRP) and San Francisco Estuary Institute’s (SFEI) 

interpretations of relevant literature on the toxicity and/or environmental fate of 

alkylphenol ethoxylates (APEOs) and their breakdown products in aquatic 

environments. The APERC reviewers made numerous specific comments regarding 

SCCWRP and SFEI concerns, offered alternative interpretations of relevant studies, 

and also cited other literature not originally referenced by SCCWRP and SFEI in their 

previous reviews. APERC’s comments can be summarized as follows: 

1) Concentrations of APEOs in California waterways are low and are not 

expected to exceed the United States Environmental Protection Agency’s 

(U.S. EPA) water quality criteria (WQC) for nonylphenol (NP), a metabolite of 

nonylphenol ethoxylate (NPE); 

2) Concentrations of APEOs in sediment are below predicted no effect 

concentrations (PNEC) for NP; 

3) APEOs are highly treatable in Waste Water Treatment Plants (WWTPs) and 

their degradation intermediates are not persistent or bioaccumulative in the 

environment; 

4) APEOs are not a major source of estrogenic activity in wastewater treatment 

effluent; and 

5) Rather than prohibiting use of APEO surfactants, concentrations should be 

monitored to evaluate occurrence of increases. 

We would like to take this opportunity to respond to APERC’s comments. In responding 

to APERC we note that our comments are reflective of SFEI’s and SCCWRP’s original 

commentary and analysis, supplemented by additional background materials obtained 

during our review of APERC’s November 17, 2010, comment letter. Also note that our 

response does not address all potentially relevant issues which may pertain to aquatic 

APEOs, e.g., APEO bioconcentration and endocrine disruption in aquatic/marine 

mammals and birds. 

For clarity I also would like to reiterate that APEOs are used in various applications as 

surfactants. This family of chemicals includes the most commercially used NPE and its 

corresponding metabolites NP, as well as octylphenol ethoxylates (OPE) and their 

degradation products octylphenols (OP). APEOs enter surface waters, for the most 

part, via discharges of treated effluent from industrial and municipal WWTP. 

Spontaneous environmental biodegradation and wastewater treatment processes form 

degradation products, NP, OP, alkylphenoxy carboxylates (APECs), and numerous 

forms of mono-, di-, and tri-ethoxylates. In reading this memorandum, the terms APEO, 

NPE, OPE, NP, and OP will be used. 
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1) APERC contends that concentrations of APEOs in California waterways are 

low and are not expected to exceed U.S. EPA’s WQC for NP 

First of all, many of APERCs comments focused on the U.S. EPA’s Aquatic Life 

Ambient Water Quality Criteria – Nonylphenol (U.S. EPA, 2005). We have reviewed 

these NP acute and chronic WQC established by U.S. EPA for both fresh and salt 

water. U.S. EPA concluded that these WQC represent concentrations where aquatic 

life and their uses should not be affected under specified durations and frequencies. 

Division of Water Quality (DWQ) staff generally agrees that California specific data 

indicate that concentrations of APEOs in several California waterways are below the NP 

acute and chronic fresh and salt WQC established by U.S. EPA. However, whether NP 

is an appropriate benchmark for evaluating relative toxicity of this entire class of diverse 

organic compounds is unclear. We are not in a position to make far-reaching 

generalizations about the environmental fate and comparative toxicity of this large class 

of substances from the relatively narrow dataset for NP, OP, and their ethoxylates. 

APERC also appended to their comments summaries of acute, subchronic, and chronic 

studies conducted on numerous aquatic species. These studies suggest concentrations 

of APEOs in California waterways are below U.S. EPA’s established NP WQC. We 

appreciate the opportunity to review these studies. On the whole, these studies tend to 

support that, at present, aquatic species are not being exposed to toxic concentrations 

of NP. However, SFEI noted that some studies suggest that the effects of APEOs and 

their degradation products may be additive. As stated earlier, it is unclear whether NP 

WQC are suitable surrogates for evaluating all potential impacts of this entire class of 

chemicals. 

Environment Canada has also established water quality guidelines for NP and its 

ethoxylates for the protection of aquatic life. The interim values are 1.0 microgram per 

liter (μg/L) for freshwater and 0.7 μg/L for marine waters (Canada, 2002). The 

European Union (EU) has also established an Environmental Quality Standard for NP. 

Under their Water Quality Directive the annual average concentration is not to exceed 

0.3 μg/L (OSPAR, 2009) with the maximum allowable concentration in inland and other 

surface water of 2.0 μg/L. We note that several reported concentrations in California 

waterways, particularly those from the Surface Water Ambient Monitoring Program 

(SWAMP), are near or exceed these levels (State Water Resources Control Board, 

2010b). These criteria values support our contention that existing concentrations of 

APEOs are of concern. 

In summary, we concur with APERCs conclusions that concentrations of APEOs are 

generally below U.S. EPA’s WQC for NP. As discussed above, however, this does not 

necessarily mean that the current concentrations are safe for aquatic species. APERC 

does not dispute that these compounds are toxic to aquatic species. We would suggest 

that, with the wealth of effective alternative, safer surfactants available, there is no need 

for exposing aquatic species to even low concentrations of these chemicals which are 

known to be estrogenic and whose effects may be additive. Therefore, our opinion as 
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to restricting use of APEOs in consumer products has not changed. We continue to 

support the California Air Resources Board’s (ARB) actions to prohibit use of APEOs in 

the nonaerosol forms of General Purpose Cleaners, Glass Cleaners, General Purpose 

Degreasers, Heavy Duty Hand Cleaner or Soap, and all forms of Oven Cleaner. 

2) APERC contends that concentrations of APEOs in sediment are below PNECs 

for NP 

APERC also disputed statements from SCCWRP that indicated sediment threshold 

levels protective of aquatic marine or freshwater life are not available. APERC provided 

NP PNEC sediment values calculated by the Canadian government (2002), as well as 

NP PNECs for benthic organisms (APERC, 2010). These NP PNECs tend to indicate 

that, in general, sediment concentrations of APEOs measured in several California 

locations are below levels of concern. However, SCCWRP cited 2005 data from 

Schlenk et al. which measured some sediment concentrations in excess of the PNECs 

calculated for marine environments. SCCWRP further indicated that more recent data 

showed concentrations to be an order of magnitude lower than those found in 2005 

(SCCWRP, 2010). Whether this same trend would be true for other waters is not 

known. As further noted by SCCWRP, very little APEO concentration data exist for 

other permitted discharges or in water bodies receiving these discharges. 

Nevertheless, we believe concentrations of APEOs detected in sediments remains a 

serious concern. For example, results of model calculations (Huang et al., 2007) 

showed that over 86 percent of all NP input for an aquatic microcosm consisting of four 

compartments (surface microlayer, water phase, water sediment, with zebra fish as 

biota) was removed by advective outflow, while of the remaining NP over 60 percent 

was distributed to the sediment phase. This finding demonstrates that sediment plays a 

key role in the fate of NP and acts as a sink in the aquatic environment. The data also 

support that measures to reduce these substances are important for water quality. 

3) APERC contends that APEOs are highly treatable in WWTP and their 

degradation intermediates are not persistent or bioaccumulative in the 

environment 

APERC’s comments include the following statement (p. 6): “While APE[O]s and their 

degradation intermediates are not ‘readily biodegradable’...they are highly treatable and 

removed from the effluent stream in wastewater treatment plants and they are 

inherently biodegradable.” 

SFEI’s July 2010 review reached a different conclusion regarding APEOs: “Wastewater 

removal efficiencies are extremely variable (9 to 94%) and sorption to sludge is the 

principal pathway for removal...recent studies suggest that urban runoff may also be a 

pathway for entry of APEOs to aquatic environments.” 
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Related to whether APEOs are persistent or bioaccumulate in the environment, 

APERC’s comment letter appears to question the validity of various researchers’ 

observations that generally support the view that APEOs exhibit a tendency toward 

biomagnification, bioaccumulation, and/or bioconcentration in marine and freshwater 

settings. However, we note that recent studies not cited by APERC, SFEI, or SCCWRP 

also indicate that these phenomena do occur. Among those, for example, Huang et al.

(2007) found that a comparatively high bioconcentration factor for NP in zebrafish was 

indicative of substantial potential for bioaccumulation in a food chain, and that 

depuration was slow and ultimately incomplete within this study’s time frame. These 

observations are consistent with Sumi et al.’s findings (2007) on the propensity of 

common carp to bioaccumulate NP, in addition to exhibiting various signs of endocrine 

disruption when exposed to ambient concentrations found in several rivers and a lake in 

Japan. We also note that in its “Nonylphenol (NP) and Nonylphenol Ethoxylates (NPEs) 

Action Plan” (Action Plan) U.S. EPA indicates that NPEs are “moderately 

bioaccumulative in mollusks, are persistent in the aquatic environment, and accumulate 

in soils and sediments” (U.S. EPA, 2010). 

Moreover, the EU determined NPEs containing more ethoxylate groups may not be 

broken down entirely during wastewater treatment. The NP group is particularly stable 

and can remain intact throughout normal wastewater processing. Data also indicate 

that NP and NPEs continue to be discharged from wastewater treatment works 

(Environment Agency, 2010). Further, the EU determined that these chemicals have a 

tendency to accumulate in the tissues of plants and animals (Environment Agency, 

2010). 

To be inclusive, we note that Canada found that APEOs, while mildly bioaccumulative in 

aquatic organisms, did not meet criteria to be considered bioaccumulative under their 

Persistence and Bioaccumulation Regulations (Canada, 2002). 

4) APERC contends that APEOs are not a major source of estrogenic activity in 

wastewater treatment effluent 

APERC’s comments express some skepticism about the capacity of APEOs to act as 

endocrine disruptors. However, recent research not referenced by APERC indicates 

that APEOs such as NP have some capacity to act as endocrine disruptors. For 

example, Baker et al. found (2009) that NP induced up-regulation of vitellogenin in 

some fish species; this metabolic response is typically associated with exposure to 

estrogenic substances, and is thus frequently employed in assays of a prospective 

endocrine disruptor’s biological activity. Vajda et al. (2008) assessed the impact of an 

estrogenic WWTP effluent on white suckers’ (Catostomus commersoni) reproduction. 

Gonadal intersex, altered sex ratios, and other changes associated with exposure to 

estrogenic wastewater contaminants were identified in fish downstream from the WWTP 

outfall but not at the upstream site. Chemical analyses determined that the WWTP 

effluent contained a complex mixture of endocrine-active chemicals including 

alkylphenols. The evidence of endocrine disruption has also been observed in male 
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fathead minnows (Pimephales promelas) exposed to WWTP effluent (Barber L. et al., 

2007). Results indicated that the reproductive potential of native fishes may be 

compromised in wastewater-dominated streams. Of particular concern would be 

effluent concentrations for discharges to saltwater because the WQC for salt water are 

much lower than those for fresh water. 

In addition, Xie et al. (2005) found that certain herbicide formulations containing APEOs 

as surfactants were “estrogenic to trout at environmentally relevant concentrations” and 

noted that these effects seemed to be additive at some concentrations. The EU also 

determined that NP has the potential to mimic hormones, namely estrogen 

(Environmental Agency, 2010). Yet another study concluded that the increasing 

occurrence, distribution, and concentration of environmental contaminants, including 

environmental estrogens (EE), in aquatic habits may also compromise the hypoosmoregulatory ability of fish (Hanson et al., 2010). Reported results indicated that EE 

reduced salinity adaptation of rainbow trout (Oncorhynchus mykiss) used in this study. 

APEOs such as 4-nonylphenol may also exert nonendocrine related deleterious effects 

on the shoaling behaviors of various fish species, as reported by Ward et al. in 2008. 

These researchers found that 4-nonylphenol, a common anthropogenic contaminant of 

coastal waters, could disrupt shoaling behavior at environmentally relevant 

concentrations. Shoaling is a group behavior common to many fish species that is 

important in reducing mortality due to predation, enhancing foraging success, improving 

hydrodynamic efficiency, and for providing enhanced opportunities for locating suitable 

mates. Though not emphasized by SCCWRP or SFEI reviewers, we consider that this 

line of research warrants further consideration in evaluating the potential aquatic toxicity 

of APEOs. 

5) APERC contends that rather than prohibiting use of APEO surfactants, 

concentrations should be monitored to evaluate occurrence of increases 

We agree that APEO concentrations should be monitored. Through U.S. EPA’s Action 

Plan additional data may be generated if NP and NPE are added to chemicals to be 

reported under the Toxic Release Inventory (TRI). However, we do not believe that 

more data are necessary to determine that APEOs are at levels of concern in California 

waterways. Moreover, we do not believe it is prudent policy to take action only if data 

indicate APEO levels are increasing over existing concentrations. 

General Comments

In addition to responding to APERC comments, I believe it is worth acknowledging other 

national and global actions related to restricting/prohibiting use, or conducting further 

testing of APEOs. First, we note several U.S. EPA actions related to APEOs. In an 

Advance Notice of Proposed Rulemaking (ANPR) dated June 17, 2009, U.S. EPA 

announced that it is initiating a rulemaking not only because of aquatic toxicity 

concerns, but also due to human health concerns (U.S. EPA, 2009a). For example, 
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U.S. EPA states in the ANPR that they are trying to determine whether a study of 

industrial laundry workers’ exposure to NPEs is warranted. The rulemaking is also 

being pursued to determine whether additional aquatic toxicity testing is necessary. 

Earlier, as part of U.S. EPA’s Design for Environment Program, the Safer Detergents 

Stewardship Initiative (SDSI) was put in place. This program recognizes manufacturers 

that voluntarily switch to safer surfactants to ‘help protect aquatic life in both fresh and 

salt water’ (U.S. EPA, 2009b). 

Most recently, on August 18, 2010, U.S. EPA released their Action Plan. This Action 

Plan is designed to “address [U.S. EPA’s] concerns about potential ecological effects 

due to the manufacturing, processing, distribution in commerce, and use of NP and 

NPEs. Additionally, EPA continues to have some concern about potential risk to human 

health. EPA anticipates that the action put forward in the Action Plan will further reduce 

human exposure thereby reducing concerns associated with NP and NPEs.” 

“..........EPA also intends to evaluate the potential for disproportionate impacts on 

children and other sub-populations.” Other potential actions include developing a 

Significant New Use Rule (SNUR) and continuing to encourage manufacturers of all 

NPE-containing direct-release products to move to NPE-free formulations. The Action 

Plan further states that household detergent manufacturers have cooperated to greatly 

reduce use of NPEs through the SDSI, and that the majority of industrial launderers 

have agreed to expedite a phase out of the use of NPEs by 2014 (U.S. EPA, 2010). 

NP and NPEs are on the List of Chemicals for Priority Action under OSPAR [Oslo and 

Paris Conventions for the Protection of the Marine Environment of the North East 

Atlantic] (OSPAR, 2009). As a result, OSPAR countries have been required to 

implement best available techniques and best environmental practices, and to achieve 

specified limit values for emissions and discharges of various waste streams, as well as 

the phaseout of specific substances. Specifically, NP and NPEs used as cleaning 

agents were recommended to be phased out in 1995 for domestic use, and in 2000 for 

industrial use (OSPAR, 2009). Because of the risks these chemicals pose to the 

aquatic environment, in the EU use of NP and NPE has been restricted in various 

categories including industrial, institutional and domestic cleaning; cosmetics and 

personal care products; and pesticides and biocides. These restrictions apply to both 

concentrated and ready-to-use products (Environment Agency, 2010). We also note 

that under the Helsinki Convention (Baltic Marine Environment Protection Commission; 

HELCOM), NP/NPEs and OP/OPEs are on the List of Priority Hazardous Substances 

(Backer et al., 2010, HELCOM, 2010). 

Since putting these directives in place, periodic monitoring by OSPAR has found lower 

concentrations of NP/NPE in marine waters protected by OSPAR/EU countries 

(OSPAR, 2009). However, data also show that NP and NPEs continue to be 

discharged from wastewater treatment works in England and Wales (Environment 

Agency, 2010). This is an indicator that APEOs are not completely removed from 

WWTP. 
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Other states, including Minnesota and Maine have taken steps to address exposure to 

APEOs. Recently, the Minnesota Pollution Control Agency developed draft numeric 

acute and chronic WQC for total NPE and developed a separate lower value of 2.4 μg/L 

(considerably lower than that of U.S. EPA’s) for the protection of cold-water fish 

(Minnesota, 2010). We note that NP and NPE concentrations measured in several 

California waterways would exceed this cold-water fish criterion (SWRCB, 2010b). 

While not water quality related, the Maine Board of Environmental Policy recently 

approved a regulation to designate the chemical class of NP and NPE as Priority 

Chemicals under the Maine Regulation of Chemical Use in Children’s Products (Maine, 

2010). 

In combination, these U.S. EPA and international actions have likely contributed to 

lowering concentrations of APEOs in California waterways as manufacturers have 

shifted from use of APEOs to comply with these actions. Clearly, ARB is not acting 

alone to reduce exposures to APEOs. 

In preparing our response to APERC we also reviewed other comments on ARB’s 

proposals. We were pleased to read that a large industry association, representing 

manufacturers of the products that would be affected by ARB’s proposed amendments, 

is not opposed to the proposed prohibition on use of APEOs (CSPA, 2010). 

Summary

In conclusion, the comments submitted by APERC do not change the information or 

recommendation conveyed in our memorandum to you on this subject dated September 

20, 2010. To reiterate, information submitted by SWAMP, SFEI and SCCWRP indicate 

that the level of aquatic toxicity posed by APEOs is high enough to cause concern. In 

fact, levels measured in several California waterways exceed WQC established by 

some jurisdictions. Given the wide availability of effective, safer alternatives, coupled 

with U.S. EPA and other jurisdictional actions, we continue to support ARB’s prohibition 

on use of APEOs in non-aerosol General Purpose Cleaners, Glass Cleaners, General 

Purpose Degreasers, Heavy Duty Hand Cleaner or Soaps, and all forms of Oven 

Cleaners. 
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