lecture 20 surfactants i. basic chemistry & uses of …es/rp 532 applied environmental...

ES/RP 532 Applied Environmental Toxicology of 15

ESRP532 Lecture 20.doc Fall 2004

November 10, 2004

Lecture 20 Surfactants

I. Basic Chemistry & Uses of SurfactantsA. A surfactant is a contraction of the descriptive phrase surface-active agent;

1. Surfactants are used in a wide variety of industrial, agricultural, and consumer productsa. Aid in the dispersion of “active ingredients” in water solutionsb. Can help the “spreading” of an active ingredient over a surface;

1. For example, pesticide sprays, usually mixed in water, will bead up on a leafsurface owing to the waxes present in the cuticlea. When the surface tension is lowered, by the surfactant in the pesticide

formulation or added to the spray mixture, the pesticide-containing waterdroplets spread across the leaf surface instead of beading up;

b. The pesticide is more readily absorbed by the leaf and/or covers a widersurface area.

Contact of spray droplets on leaf surface. Without surfactant (A), water droplets bead up on aleaf surface (which is covered in hydrophobic waxes). With surfactant, water droplets spreadover a greater surface area owing to a reduced surface tension of water.

2. Because of the ubiquitous use of surfactants, for ex. in shampoos & detergents, theyenter into wastewater streams and residual concentrations not degraded in treatmentplants are discharged into aquatic systems.a. Also, treated sewage sludge may be disposed on land (for ex., it may be allowed for

use as an agricultural fertilizer).B. Physicochemical Nature of Surfactants

1. Surfactants are surface active because they concentrate at interfacial regions: air-water,oil-water, and solid-liquid interfaces

2. The role of surfactants (i.e., surface active agents) is to decrease the surface tension ofwater by overcoming the barriers of solvent-solvent interactions;a. In other words, surfactants essentially promote greater dispersion of solute

molecules in the water.b. One result of such interactions is a raising of a solute’s water solubility; thus more

solute can be “dissolved” per unit volume of waterc. The “solvating” properties of surfactants have made them useful for

bioremediation, where biodegradation of hydrophobic contaminants can beaugmented by adding surfactants to increase their bioavailability.

3. The surface activity derives from their amphiphilic charactera. Amphiphilic (a.k.a. amphipathic) molecules consist of a nonpolar hydrophobic

portion (“tail”), usually a straight or branched hydrocarbon or fluorocarbon chaincontaining 8-18 carbon atoms, which is attached to a polar or ionic hydrophilicportion (“head”). The latter will associate with water, while the former with thewater:air interface or with the apolar phase (in two phase systems)



b. The hydrophilic portion can be nonionic, ionic (anionic or cationic), or zwitterionic(containing both negative and cationic charges) accompanied by counterions.1. General and representative structures for surfactants;

a. n represents a variable number of carbon or hydrogen atoms; (CH2-CH2-O)is an ethylene oxide unit where m represents a variable number of units in amolecule;



c. The hydrophilic and hydrophobic portions of the surfactant molecule are wellseparated; the hydrophobic part interacts weakly with the water molecules in anaqueous environment; the polar or ionic group interacts strongly, mainly viahydrogen bonding (i.e., dipole-dipole interactions, ionic-dipole interactions);1. It is the latter strong interactions with the water molecules that renders the

molecule soluble in water; however, owing to entropy considerations, thehydrophobic portion is “squeezed” out of water; this leads to an accumulationof molecules at interfaces (this interface could be the interface of two liquids, asolid and a liquid, etc.).

2. The hydrophobic groups will associate with hydrophobic surfaces (ormolecules, solid particles, oil droplets, etc.), while leaving the hydrophilic groupin contact with water.

3. At a specific concentration of surfactant molecules in water, the hydrophobic andhydrophilic parts will align in self association to form approximately sphericalunits (or other shapes such as laminations) called micelles; this concentrationwhere self-association leads to micelle formation is called the cmc or criticalmicelle concentration

Surfactant units with hydrophilic “heads” oriented in water and hydrophobic“tails” oriented outward toward the surface of water. (Graphic clipped fromhttp://www.ksvinc.com/cmc.htm)

Micelle Unit: At a critical concentration, surfactants (and/or lipids) will aggregate in astructure with hydrophobic tails oriented toward one another and the hydrophilic headsoriented toward the water phase. ((Graphic clipped from http://www.ksvinc.com/cmc.htm)

4. As the surfactant concentration increases, the properties of the solution change(see next graph)a. More micelles are formed, further lowering surface tension but also raising

turbidity5. As the surfactant lowers water’s surface tension, hydrophobic molecules (like a

typical nonionic pesticide) can more easily disperse (essentially raise its WS to ahigher value) and become totally solvated. The mechanism is essentially acomplex interaction between the surfactant, water, and the solute (i.e., an activeingredient like a pesticide, perhaps a dye for textiles, etc.)



6. Thus surfactants are added to various pesticide and industrial and consumerproduct formulations to stabilize the interactions between the water and chemicaland allow increased solvation or dispersion

C. Commonly Used Surfactants1. Linear Alkylbenzenesulfonates, a.k.a. LAS [source: Larson, 1990, ES&T 24:1241]--

probably the most common anionic surfactanta. Widely used in the detergent industry in laundry and cleaning products;

1. Production volumes are approximately 2.8 billion pounds;2. Consumption estimated at ~1.5-2 million tons per year (reported in Elsgaard et

al. 2001, ETAC 8:1656)b. Developed in the mid-1960’s as a readily biodegradable replacement for branched-

chain alkylbenzenesulfonates (ABS);1. ABS was associated with foaming of sewage effluent receiving waters and was

also not readily biodegradable [source: Field et al., 1992, ES&T 26:1140].c. Structural characteristics:

1. Alkyl substituent can be attached to benzene ring at various sites2. Normally, the alkyl chain has 7 - 14 carbons

SO3- Na+

2. Linear Alcohol Ethoxylates (LAE) --the most common nonionic surfactant [source:Talmadge, 1994, “Environmental & Human Safety of Major Surfactants]a. Usage:

1. Used in significant amounts in industrial products since the 1930’s2. Usage grew after WWII in household and institutional cleaners3. Usage from the mid-1960’s in laundry products (highest end use)

a. Less sensitive to water hardness than competing materialsb. Low foaming abilityc. Very effective at removing oily soils

4. Widespread use in consumer products grew in 1970’s and 1980’s



b. Production1. 0.7 billion pounds produced in U.S. during 19882. 0.3 billion pounds consumed in U.S. during 1988 in U. S. household detergents3. 0.1 billion pounds used in institutional and industrial applications

c. Structural characteristics1. Commercial materials are actually a mixture of polyoxyethylene adducts with a

primary or branched chain alcohol2. Thus, they are typically described by the average moles of ethylene oxide (EO)

added per mole of alcohol or by the percent EO in the product; so there will be adistribution of EO units represented in any commercial LAE;

3. Alkylphenol Ethoxylates [a.k.a. APE]--[source: Talmadge, 1994, “Environmental &Human Safety of Major Surfactants]a. Most commonly used APE is nonylphenol ethoxylate (9 carbon alkyl chain);b. Used in cleaning products and industrial processing for more than forty years;

1. The extensive use of APEs (as well as other surfactants) is illustrated byexamining one product called Tergitol that is made by Dowa. Tergitol surfactant various in molecular wt. From 396-3300, and has

ethoxylate unit numbers ranging from 4 to 70, respectively.b. The technical sheet touts the following applications:

1. Adhesives/sealants wetting agents and stabilizers2. Agricultural emulsifiers, wetting agents, dispersants3. Antifog and antistat agent for plastic films4. Asphalt emulsions5. Defoamer6. Dust control agent for coal and mining operations7. Emulsifier

a. Chlorinated solvent systemsb. Emulsifier for fats, waxes, kerosene, mineral oil

8. Household applicationsa. All purpose cleaners and degreasersb. Car wash and car care productsc. Laundry detergentsd. Prewash spotter removerse. Solid toilet bowl cleaners

9. Industrial and institutional cleanersa. Alkaline bottle washingb. Circuit board cleanersc. Dairy and food plant cleanersd. Dry cleaning detergentse. Hard-surface cleaners and degreasersf. High-pressure car wash detergentsg. Metal cleanersh. Solvent-based emulsion cleaners

c. Leather hide soaking, tanning, and dyeing operationsd. Metalworking fluidse. Oil field chemicalsf. Paints/coatings and emulsion polymerization

1. Defoamer2. Emulsion polymer manufacturing3. Emulsifier and stabilizer for p0lyester resins and polymers4. floor finishes emulsifier/stabilizer5. Freeze thaw stabilizer6. Pigment wetting agents and dispersants7. Wetting agent for paints/coatings



g. Pulp/paper de-inking, felt cleaning, and processing aidsh. Textile processing

1. Dye assist and leveling agents for carpets and textiles2. Textile scouring operations3. Textile wetting agent4. Emulsifier for fiber lubricants and coning oils

c. Total U. S. sales of APE exceeded 0.5 billion pounds in 1988; an estimate ofworldwide production in 1997 concluded about 1 billion pounds are producedannually (cited in Isobe et al. 2001).1. 55% of the total used are industrial, including

a. Plastics and elastomers: emulsion polymerization; acrylic and vinyl acetatepolymerization processes; stabilizer for the final latex;

b. Textiles: used for adapting the general processes of cleaning, spinning,weaving, and finishing to the full range of fiber types; excellent wettingagents with good handling and rinsing characteristics;

c. Agricultural chemicals: used as emulsifiers; enhancers and wetting agents toimprove adhesion of toxicant;

d. Paper: used as dispersants in the pulping process, for paper de-inking, anddissolving pulp.

2. 30% of total used in institutions--i.e., for cleaning products (metal andcommercial vehicles cleaners, commercial laundry products, hard surfacecleaners);

3. 15% of total used in household and personal care products (this marketdominated by LAEs instead).

d. Structural characteristics:1. Composed of an alkyl chain, usually branched, attached to a phenol ring which

is combined, via an ether linkage, with one or more ethylene oxide or(poly)oxyethylene units.a. Nonylphenol ethoxylate--note that in this example there are 9 ethoxylate

units; an abbreviation for this structure is NP9EO.

C9H19 O(CH2CH2O)9 H

OH

4-nonylphenol

2. The APEs are generally biodegradable, but end decomposition products includenonylphenols and octylphenol

II. Environmental ChemistryA. Comparison of Physicochemical Properties (from Jacobsen et al. 2004. J. Environ. Qual. 33:232

Property Linear alkyl benzenesulfonate (LAS)

Nonylphenolethoxylate (NPE)

Nonyl phenol(NP)

Molecular Weight 297-339 (C10-C13) 264-352 (n=1-3) 220Water solubility(mg/L)

35-90 3.02-5.88 (n-1-3) 5.43

Critical micelleconcentration (mg/L)

100-1000 3-300 --

Log Kow 0.6-2.7 4.17-4.20 4.48Kd (soil) (L/kg) 8.5-322Kd (sediment) (L/kg) 44.7-3,020 450-1,460 --Kd (sludge) (L/kg) 256-12,140 12,000-13,000 --



B. LAS1. Environmental concentrations (water)--microgram per liter levels;

a. LAS concentrations along the length of the Mississippi River were studied in theearly 1990’s.1. Abstract from Tabor, C. F. Jr. and L. B. Barber. 1993. Linear alkylbenzene sulfonate in

the Mississippi River. U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the Technical Meeting, Colorado Springs, Colorado, September 20-24, 1993,Water-Resources Investigations Report 94-4015; http://toxics.usgs.gov/pubs/cos-procee/sec.j- cont.transport/tabor.final.html a. “Linear alkylbenzene sulfonate (LAS), the active component in most

detergents, is one of the most common synthetic organic compounds foundin natural waters and sediments. The estimated LAS loading in theMississippi River basin is 3,500 kilograms per day. A detailed samplingprogram was undertaken by the U.S. Geological Survey to determine theoccurrence and fate of LAS in a 2,800 kilometer section of the MississippiRiver from Minneapolis, Minn., to New Orleans, La. LAS was identifiedand quantified in 22 percent of the water samples at concentrations rangingfrom 0.06 to 28.2 micrograms per liter. Most dissolved LAS wasassociated with the sewage treatment plant outfalls of large cities along theriver. LAS was identified in all of the composite bottom sediment samplesat concentrations of 0.01 to 20 milligrams per kilogram. Sorption tosediment removes 5 to 30 percent of dissolved LAS. On the basis ofhomolog and isomer data, biodegradation is the most important removalprocess affecting dissolved LAS.”

2. LAS as well as other surfactants can accumulate in municipal sludge, which is thanlandspread on soil, especially agricultural soil;a. Biodegradation is the predominant removal mechanism in soil;b. Knaebel et al. (1990, “Mineralization of linear alkylbenzene sulfonate [LAS] and

linear alcohol ethoxylate [LAE] in 11 contrasting soils,” ETAC 9:981-988] testedthe biodegradation rate of LAS (with a 13 carbon alkyl chain, i.e., tridecylbenzenesulfonate) in 11 different soils;1. Soils spike with radiolabelled chemical at a rate of 50 ppb;2. Monitored 1 4CO2 evolution (i.e., mineralization);3. Found LAS was mineralized in every soil without a lag period;

a. Among the soils, 16 - 70% was recovered as CO2b. Other studies have shown that 18-81% of the radioactivity is incorporated

into humus (i.e., bound residue formation);4. Half-lives ranged from 1.1 - 3.6 days and degradation exhibited first-order

kinetics;a. Other studies using higher concentrations (2.5 - 250 ppm) observed half-

lives ranging from 5 - 25 days.3. Biodegradation has been extensively studied in water at various concentrations, but one

study (Larson, R. J., 1990, Structure-activity relationships for biodegradation of linearalkylbenzenesulfonates, Environ. Sci. & Technol. 24:1241) has measured degradationof concentrations close to environmental levels (10 ppb - 100 ppb);a. Observed that mineralization was extensive (~80% of radiolabel recovered as carbon

dioxide);1. a. Half-lives varied from 15-33 h.



b. Kinetics followed first-order in river water and in river water with sediment;c. The rate and extent of mineralization were not significantly affected by the length of

the alkyl chain or the point of attachment of the benzene ring to the alkyl chain;4. Despite large percentages of sorption to sediment, biodegradation rate nor extent of

mineralization were affected.5. Leaching of LAS added to soil in sewage sludge seems to be nil (Jacobsen, A. M., G. K.

Mortensen, and H. C. B. Hansen. 2004. Degradation and mobility of linear alkylbenzene sulfonateand nonylphenol in sludge-amended soil. J. Environ. Qual. 33:232-240)a. Anaerobic sewage sludge was incorporated into the top 15 cm of a sandy loam soil

column 45 cm in length; LAS concentration was 38 mg/kg1. Planted spring barley in the soil column

b. The column was leached with a total of 700 mm of precipitationc. Within 10 days, the concentration had declined to 25% of the initially added amount

1. After 110 days, LAS concentrations were less than 1% of the amount added.d. No LAS residues (detection limit=4µg/L) were detected in leachates

C. LAEs1. Residues can be detected in water (on the order of ppb, but note that there are no current

requirements for monitoring, and therefore they are not routinely monitored),a. Formerly detected using nonspecific colorimetric methods;

1. In one study, using the above method, 30 µg/L found above a sewage outfall inthe U. S. and 240 µg/L found below the outfall.

2. The concentrations of C1415AE7 (i.e., a 14-15 carbon-containing alkyl group and7 units of ethylene oxide) as detected by GC analysis in the correspondingsamples (above and below the outfall) were 0.5 µg/L and 1.1 µg/L, respectively.

3. A river water sample obtained from a raw water tap at a water treatment plantcontained 4.2 µg/L.

b. Thus, environmental levels of specific LAEs are probably ~1-10 µg/L.2. Biodegradation in 11 soils spiked at 50 ppb (the Knaebel et al., 1990 study cited above)

gave very similar results as was observed for LAS;a. Thus, mineralization to carbon dioxide accounted for 25 - 69% of the added

radioactivity without a lag period3. Removal from wastewater treatment ranges from about 80 to 98% efficient, suggesting

that effluent will still be contaminated with measurable levels.D. APEs

1. Find residues in water at levels in low ppb2. Biodegradable; note that nonylphenol is formed--this compound is being tagged as an

“environmental estrogen”, which reputedly has endocrine system disrupting abilities;3. It has been estimated that 60% of the 300,000+ tonnes of APEs produced annually

worldwide ends up in the aquatic environment after sewage treatment as short chainalkylphenol polyethoxylates, alkylphenol carboxylic acids, and alkylphenols (includingnonylphenol and octylphenol);a. In the sewage treatment plant, the alkylphenol polyethoxylates (APEs or

alternatively, APEOs) are biodegraded; the generalized pathway of primarybiodegradation (Talmadge 1994) is shown on the next page;

b. Specific degradation products tested for estrogenic effects include:



H19C9 O CH2COOH

H19C9 O CH2CH2OCH2CH2OH

nonylphenoldiethoxylate (NP2EO)

nonylphenoxycarboxylic acid (NP1EC)

octylphenol

H17C8 OH

nonylphenol

OHH19C9

4. Domestic sewage effluents can contain up to hundreds of ppb of alkylphenoliccompounds, but industrial effluents (including. those originating from pulp mills andtextile plants) may contain significantly higher concentrations (Jobling et al. 1996,Inhibition of testicular growth in rainbow trout (Oncorhynchus mykiss) exposed toestrogenic alkylphenolic chemicals, Environ. Toxicol. Chem. 15:194-202).



OR [CH2CH2O ]

alkylphenol polyethoxylate (APEO)

Hn

n-1HOR [CH2CH2O ]

OR [CH2CH2O ] H3

alkylphenol triethoxylate (APEO3)

2HOR [CH2CH2O ]OR CH2CH2OCH2COOH

alkylphenoxyethoxy acetic acid

OR CH2COOH

alkylphenoxy acetic acid

+ +alkylphenol diethoxylate (APEO2)

OR [CH2CH2O ] H1

alkylphenol monoethoxylate (APEO1)

OHR

alkylphenol

a. While many alkylphenols are concentrated in the sewage sludge,hydrophilic compounds like NP, NP1EC and NP2EO will mostly bein the liquid effluent;

b. Concentrations of various surfactants (LAS and NPEO) and NP(nonylphenol) in raw sewage samples (liquid and solid phase) andtreated sewage have been measured in a study from Italy (Di Corcia,A., R. Samperi, R., and A. Marconmini, 1994, Monitoring aromaticsurfactants and their biodegradation intermediates in raw and treated



sewages by solid-phase extraction and liquid chromatography,Environ. Sci. Technol. 28:850-858);

Concentrations (µg/L) of Various Linear Alkylbenzene Sulfonates and Alkylpolyethoxylates

SurfactantRaw Sewage Treated Sewage

Liquid Solid Liquid SolidC9 LAS 239 13 0.8 --C1 0 LAS 959 271 3.3 0.1C1 1 LAS 1139 907 8.1 1.3C1 2 LAS 684 1676 5.9 2.2C1 3 LAS 138 1100 1.9 1.8Total NPEO 154 49 6.9 3.0NP (nonylphenol) 1 11 0.3 0.7

1. In a treated sewage sample collected by Di Corcia et al. (1994)during the month of December, 145 ppb of NP1-3EC (i.e., thecarboxylate form with 1 to 3 ethoxy units, or NPEC for short) wasdetected.

5. River water concentrationsa. As summarized by Jobling et al. (1996), river water concentration of NP (nonylphenol)

rarely exceed 10 µg/L but in rivers receiving significant amounts of industrial effluents,concentrations may exceed 100 µg/L

b. Only about 72,000 tonnes per year of OPEO (octylphenol ethoxylates) are used sodetection of OP (octylphenol) occurs less frequently (but it hasn’t really been widelymonitored) than detection of NP.

c. NP1EC has been reported at levels up to 45 µg/L with an average concentration oftenexceeding 10 µg/L.

6. Historical Trendsa. Nonylphenol was analyzed in sediments from a limnological core taken in Tokyo

Bay. Note that in contrast to what we had discussed about the historical trends ofPCBs, dioxins, and PAHs, the alkylphenols are of more recent vintage, suggestingthat they have arisen solely as a result of recent human activity. (Yamashita et al.2000, ES&T 34:3560)



b. Although the study by Yamashita et al. suggest a “stable” concentration ofnonylphenol (i.e., deposition rates have not changed much since the 1980’s),another study by Isobe et al. (ES&T, 2001, 35:1041) have suggested that depositionhas decreased since the late 1970’s as a result of the implementation of waterpollution control laws (see PowerPoint presentation).

III. ToxicologyA. LAEs

1. Acute oral LD50 rats range from 544->25,000 mg/kg; dermal values (rabbit) rangedfrom 2000->5000 mg/kg.

2. Nongenotoxic (do not mutate DNA); no carcinogenic effects; rapidly metabolized andexcreted;

3. Ecotoxicity:a. Freshwater fish: LC5 0 ~0.4 - 10 mg/Lb. Crustaceans: LC5 0 ~0.3 - 20 mg/L

B. B. APEs1. Acute oral LD50 rats range from 1420 to >28,000 mg/kg; dermal in rabbits range from

>2000 mg/kg to > 10,000 mg/kg.2. Negative in carcinogenicity tests; not mutagenic;3. 3. Ecotoxicity

a. Freshwater fish: LC5 0 ~1.3 - 1000 mg/Lb. Crustaceans: LC5 0 ~2.9-10,000 mg/L

4. Endocrine Disrupting Effectsa. At least two groups of researchers, one in the U.S. and one in the U.K., have

detected elevated levels of vitellogenin in male fish that have been captured nearmunicipal sewage outfalls;1. U.S.: (Folmar, L. C. et al. 1996, Vitellogenin induction and reduced serum

testosterone concentrations in feral male carp (Cyprinus carpio) captured near amajor metropolitan sewage treatment plant);

2. U.K.: (Harries et al. 1996, A survey of estrogenic activity in United Kingdominland waters, Environ. Toxicol. & Chem. 15:1993-2002)

b. What’s the big deal about vitellogenin detection in male serum of fish?1. Vitellogenin is a lipophosphoprotein normally synthesized in the female liver

under the control of estradiol; it is transported by the blood to the ovary where itis taken up into the oocytes during yolk formation;a. In maturing female fish it is found in the plasma in large amounts (up to 100

g/L, often constituting over 50% of blood protein)2. Males have very little estradiol, thus, normally you would not expect to see

vitellogenin (also, why would a male produce it when they have no eggs in whichto develop yolk proteins); however, there does seem to be a detectablebackground level of about 10 µg/L (as described in Harries et al. 1996),

3. Exposure of males to estrogen has been associated with the production ofvitellogenin;

4. Thus, the presence of vitellogenin in the plasma of a male fish is a very sensitivebiomarker of exposure to an estrogenic chemical (Jobling et al. 1996).

c. Dose-response studies and single dose testing of NP, OP, NP1EC, and NP2EO havebeen studied by Jobling et al. (1996) [article appended]; EE2 (ethynylestradiol), apotent synthetic estrogen, was used as a positive control.



1. The potency of the APEO degradation products is perhaps 100,000 times less than thatof estradiol in stimulating or causing vitellogenesis (i.e., vitellogenin production) andreduced testicular size;

2. Concentrations of 20.3 µg/L NP and 4.8 µg/L OP were the lowest doses tested thatcaused vitellogenin production in rainbow trout (i.e., these concentrations were theLOEL);

3. The corresponding NOELs were 5.0 and 1.6 µg/L, respectively, for NP and OP;4. In these experiments, fish were exposed to the indicated concentrations for 3 weeks;

thus, given the actual river water concentrations, the LOELs indicate a good probabilityfor a real environmental effect.

5. Jobling and Sumpter (1993) used cultured hepatocytes (liver cells) to test the effects ofvarious alkyl phenols with various alkyl chain lengths (Aquatic toxicology 27:361-372).a. They hypothesized that production of vitellogenin was under control of estrogen;b. As in the later studies with fish in-vivo, this in-vitro study also observed increases in

vitellogenin production.c. The estrogenic control of vitellogenin production was confirmed by incubating the

antiestrogenic chemical, tamoxifen, with the hepatocytes in the presence of thealkylphenols. Vitellogenin production was suppressed as a result.

d. They also noted that the longer the alkyl chain, then the less potent was the alkylphenol.

Effect of estrogenic alkylphenolic compounds (30 µg/L) and EE2 (2 ng/L) on the synthesis of vitellogeninand testicular growth in male rainbow trout exposed for 3 weeks. NP1EC is nonylphenoxycarboxylic acid;NP2EO is nonlyphenoldiethoxylate. EE2 (ethynylestradiol) is very potent synthetic estrogen. Thevitellogenin was measured in the blood plasma, and testicular growth was measured as the gonadosomaticindex (GSI) (Jobling et al. 1996, Environ. Toxicol. & Chem. 15:194-202)

d. In-vitro studies have shown both NP and OP to have estrogenic activity1. Soto et al., 1991, p-nonylphenol: an estrogenic xenobiotic released from

“modified” polystyrene, Environ. Health Perspectives 92:167-173;2. White, R. et al. 1994, Environmentally persistent alkylphenolic compounds are

estrogenic. Endocrinology 135:175-182.



e. Sumpter, who was responsible for pointing out the estrogenic activity found insewage effluents, now thinks that the alkyl phenols may not be the main culprit. Inpapers published in fall of 1998, his group showed that natural estrogens may be themain culprit that cause endocrine effects in fish near sewage outfalls. (Desbrow, C.;Routledge, E. J.; Brighty, G. C.; Sumpter, J. P., and Waldock, M. Identification ofestrogenic chemicals in STW effluent. 1. Chemical fractionation and in vitrobiological screening. 1998; Environ. Sci. & Technol. 32:1549-1558; Routledge, E. Jet al. Identification of estrogenic chemicals in STW effluent. 2. In vivo responsesin trout and roach. 1998; ES&T 32:1559-1565.)

f. On the other hand, recent research in Spain did not rule out the possible contributionnonylphenol to vitellogenin induction in male carp (Sole et al. Environ. Sci. Technol.2000, 34:5076-5083).1. Note that male carp collected in the vicinity of STPs showed elevated levels of

vitellogenin.

Alkylphenol concentrations in water upstream and downstream of sewage treatment plants (STPs)in Spain

Site Distance toSTP (km)

NP(µg/L)

NPEO (µg/L) NPEC

Anola TributarySite 1 (upstream) 5 18 <0.2 <0.08Site 2 (downstream) 23 644 100 70Site 3 (downstream) 27 <0.15 <0.2 <0.08Cardener TributarySite 1 (upstream) 1.5 51 <0.2 <0.08Site 2 (downstream) 4 398 20 40Site 3 (downstream) 8 42 <0.2 <0.08STP, Sewage Treatment Plant; NP, nonylphenol; NPEO, nonylphenol polyethoxylated; NPEC,nonylphenol monoethoxycarboxylate

Vitellogenin content is expressed as the percent relative to a positive control (male fish injected withsynthetic estrogen. Control fish were not exposed to alkylphenols.

g. Regardless of the cause of “feminization” in carp collected near STPs, Europe,England, France, Germany, and the Scandinavian countries have instituted avoluntary ban on APE use in household cleaning products, and restrictions onindustrial cleaning applications are set to follow in 2000 (Renner, 1997, ES&T31:316A).

C. Nonyl phenols may be ubiquitous in food (Guenther et al. 2002, Environmental Science andTechnology 36:1676-16801. Found NPs in all food items; concentrations from 0.1 µg/kg – 19 µg/kg



2. Intake estimated at 7.5 µg/day; infants fed breast milk and formula at 0.2 µg/day and1.4 µg/day, respectivelya. Note that breast milk was estimated to have NP at an average concentration of about

~0.3 µg/kg fresh weight3. Putative sources: formulation residues from pesticide applications;

tris(nonylphenol)phosphite antioxidant used in plastic packaging; surfactants indisinfectants

lecture 20 surfactants i. basic chemistry & uses of …es/rp 532 applied environmental...

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