Environ. Sci. Technol. 2002, 36, 2839-2847
Removal of Fragrance Materials during U.S. and European Wastewater Treatment S T A C I L . S I M O N I C H , * ,† TOM W. FEDERLE,† WILLIAM S. ECKHOFF,† ANDRE ROTTIERS,‡ SIMON WEBB,§ DARIUS SABALIUNAS,# AND WATZE DE WOLF§ The Procter & Gamble Company, Product Safety and Regulatory Affairs, Cincinnati, Ohio 45217-1087, Procter & Gamble Eurocor, Strombeek-Bever, Belgium, Procter & Gamble, Product Safety and Regulatory Affairs, Strombeek-Bever, Belgium, and Procter & Gamble, Product Safety and Regulatory Affairs, Rusham Park, U.K.
The concentrations and removals of 16 fragrance materials (FMs) were measured in 17 U.S. and European wastewater treatment plants between 1997 and 2000 and were compared to predicted values. The average FM profile and concentrations in U.S. and European influent were similar. The average FM profile in primary effluent was similar to the average influent profile; however, the concentration of FMs was reduced by 14.6-50.6% in primary effluent. The average FM profile in final effluent was significantly different from the primary effluent profile and was a function of the design of the wastewater treatment plant. In general, the removal of sorptive, nonbiodegradable FMs was correlated with the removal of total suspended solids in the plant, while the removal of nonsorptive, biodegradable FMs was correlated with 5-day Biological Oxidation Demand removal in the plant. The overall plant removal (primary + secondary treatment) of FMs ranged from 87.8 to 99.9% for activated sludge plants, 58.6-99.8% for carousel plants, 88.9-99.9% for oxidation ditch plants, 71.3-98.6% for trickling filter plants, 80.8-99.9% for a rotating biological contactor plant, and 96.7-99.9% for lagoons. The average concentration of FMs in final effluent ranged from the limit of quantitation (1-3 ng/L) to 8 µg/L. Measured FM removal and concentrations were compared to predicted values, which were based on industry volume, per capita water use, octanol-water partition coefficient, and biodegradability.
Introduction In recent years, our understanding of the analytical chemistry, environmental fate and transport, ecotoxicology, and envi* Corresponding author phone: (541)737-9194; fax: (541)737-0497; e-mail:
[email protected]. Current address: Department of Environmental and Molecular Toxicology and Department of Chemistry, Oregon State University, Corvallis, OR 97331. † The Procter & Gamble Company, Product Safety and Regulatory Affairs, Cincinnati, OH. ‡ Procter & Gamble Eurocor, Strombeek-Bever Belgium. § Procter & Gamble, Product Safety and Regulatory Affairs, Strombeek-Bever Belgium. # Procter & Gamble, Product Safety and Regulatory Affairs, Rusham Park, U.K. 10.1021/es025503e CCC: $22.00 Published on Web 05/21/2002
2002 American Chemical Society
ronmental risk assessment of fragrance materials (FMs) has become more refined. Improved analytical methods include the identification of the metabolites of nitro musks (NMs) and polycyclic musks (PCMs) in aquatic matrices (1, 2), identification of the enantiomeric composition of PCMs in aquatic species (3), the use of solid-phase microextraction to measure FMs in water (4) and in air (5), and identification and quantification of a wide-range of FMs in aqueous matrices (6). Although much of the research on the environmental fate of FMs continues to focus on the aquatic environment (1-4, 6-12), NMs and PCMs have been detected in Norwegian air samples (13), and the atmospheric lifetimes of selected fragrance materials have been measured (5). Recent research on the ecotoxicity of FMs includes clarification of the ecotoxicity of amino-metabolites of NMs to Daphnia magna (14-16), developmental toxicity of NMs to Xenopus laevis and Danio rerio (17), and investigations of the estrogenic activity of NMs (18) and PCMs (19). The European Union Technical Guidance Documents (EUTGD) and the European Union System for the Evaluation of Substances (EUSES) have been used to conduct exposure, effect, and risk assessments for PCMs (20-22) and nitromusks (23). More recently, a framework has been developed to prioritize fragrance materials for aquatic risk assessment in the U.S. and Europe (24). In developed geographies, the primary route of FM entry to the environment is through use of consumer products that are discharged down-the-drain to municipal wastewater treatment. The objective of this study was to determine the concentrations and removals of a wide range of FMs in many different types of wastewater treatment, in the U.S. and Europe and to compare these to predicted values (24). Previously developed analytical methods were used, and 16 semivolatile FMs were chosen as analytes because they span a wide range of physical chemical properties and biodegradability (Table 1) (6). The structures of these fragrance materials are given in ref 6. Seventeen different wastewater treatment plants were sampled between 1997 and 2000, including activated sludge, carousel, oxidation ditch, trickling filter, rotating biological contactor, and lagoon plants. We chose these types of plants because they treat the majority of household wastewater in both the U.S. and Europe (25, 26). The data generated will ultimately be used for estimating aquatic concentrations, for use in environmental risk assessment.
Experimental Section Chemicals, Analytical Methods, and Sampling Procedures. All chemicals, analytical methods, sampling procedures, and sample preservation methods have been previously described (6). Analytes included benzyl acetate (phenylmethyl ester acetic acid), methyl salicylate (2-hydroxy-methyl ester benzoic acid), methyl dihydrojasmonate (3-oxo-2-pentyl-methyl ester cyclopentaneacetic acid), terpineol (4-trimethyl-3cyclohexene-1-methanol), benzyl salicylate (2-hydroxyphenylmethyl ester benzoic acid), isobornyl acetate (1,7,7trimethyl-acetate bicyclo[2.2.1]heptan-2-ol), g-methyl ionone (3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2one), p-t-bucinal (4-(1,1-dimethylethyl)-R-methyl-benzenepropanal), musk ketone (3,5-dinitro-2,6-dimethyl-4-tertbutyl-acetophenone), musk xylene (1-(1,1-dimethylethyl)3,5-dimethyl-2,4,6-trinitro-benzene), hexylcinnamaldehyde (2-(phenylmethylene)-octanal), hexyl salicylate (2-hydroxyhexyl ester benzoic acid), OTNE (1-(1,2,3,4,5,6,7,8-octahydro2,3,8,8-tetramethyl-2-naphthalenyl)ethanone), acetyl cedrene (3R-(3a,3ab,7b,8aa))-1-(2,3,4,7,8,8a-hexahydro-3,6,8,8VOL. 36, NO. 13, 2002 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
9
2839
TABLE 1. FM Properties That Are Relevant to Wastewater Treatmentg fragrance material
CAS
MW, g mol-1
Kd, L kg-1
H, Pa m3 mol-1
biodegradability
benzyl acetate methyl salicylate methyl dihydrojasmonate terpineol benzyl salicylate isobornyl acetate g-methyl ionone p-t-bucinal musk ketone musk xylene hexylcinnam-aldehyde hexyl salicylate OTNE acetyl cedrene AHTN HHCB
140-11-4 119-36-8 24851-98-7 98-55-5 118-58-1 125-12-2 127-51-5 80-54-6 81-14-1 81-15-2 101-86-0 6259-76-3 54464-57-2 32388-55-9 1506-02-1 1222-05-5
150.2 152.2 226.3 154.3 228.3 196.3 192.3 204.3 294.3 297.3 216.3 222.3 234.4 246.4 258.4 258.4
132d 247d 408d 595d 2081d 2081d 3030d 1836d 2081d 4412d 4412d 9355d 12020d 12020d 12020d (10040c) 15400d (12780c)
2.04b 0.0607b 0.135b 0.939b 0.00416b 84.4b 89.4b 12.4b 0.0061e 0.018e 5.00b 0.118b 31.8b 14.7b 12.5f 11.3f
readya readya readya readya inherenta readya inherenta readya not biodegradablea not biodegradablea inherenta readya not biodegradablea inherenta not biodegradablea not biodegradablea
a Measured (28). b Estimated (29). c Measured (21). d Estimated (24) using log K e Estimated (23). f Estimated (21). g Ready indicates ow from ref 6. the material passed the OECD Ready Biodegradability test criteria, including the 10-day window. Inherent indicates the material passed an OECD inherent biodegradability test or produced CO2 (but did not meet the 10-day window) in the OECD Ready Biodegradability test. Not Biodegradable indicates the material did not degrade in standard OECD biodegradation tests. CAS is the Chemical Abstract Number, MW is the molecular weight, Kd is the sorption coefficient for activated sludge, and H is the Henry’s law constant.
TABLE 2. Location, Type of Treatment, Sampling Dates, Wastewater Influent Flow, and General Operating Conditions of the Wastewater Treatment Plants Monitoredc location OHa
Loveland, Carmel, IN Lodi, CA Durham, OR Crofton, Yorkshire U.K. De Meern, Netherlands Kralingseveer, Netherlands Rockaway Valley, NJ Opelike, AL Glendale, OHa Oskaloosa, IA Sedalia, MO Stretford, Manchester U.K. Meltham, Yorkshire U.K.b St. Clairsville, OH San Benito, TX Rose Hill, KS
geography
treatment type
U.S. U.S. U.S. U.S. Europe Europe Europe U.S. U.S. U.S. U.S. U.S. Europe Europe U.S. U.S. U.S.
P + AS P + AS P + AS P + AS P + AS P+C P+C OD (no P) OD (no P) P + TF P + TF P + TF P + TF P + TF P + RBC L (no P) L (no P)
sampling dates
plant flow l day-1
removal BOD5 (%)
removal TSS (%)
9/22/97-9/24/97 11/3/98-11/5/98 10/18/99-10/20/99 10/25/99-10/27/99 9/7/00-9/8/00 4/12/99-4/15/99 4/19/99-4/22/99 6/8/99-6/10/99 12/7/99-12/9/99 10/6/97-10/9/97 8/16/99-8/19/99 8/23/99-8/25/99 4/27/99-4/29/99 9/5/00-9/6/00 6/15/99-6/17/99 3/23/99-3/25/99 9/21/99-9/23/99
2.1 × 3.0 × 107 2.5 × 107 9.5 × 107 1.8 × 106 1.7 × 107 1.0 × 108 4.5 × 107 2.6 × 106 1.5 × 106 3.0 × 106 3.8 × 106 1.6 × 107 4.3 × 106 1.3 × 107 4.9 × 106 1.4 × 106
98.2 98.1 98.8 98.5 98.4 95.1 95.1 96.6 99.0 93.4 93.8 88.7 87.5 98.7 93.8 87.5 90.9
99.1 97.6 97.5 99.5 91.6 81.4 93.0 85.7 91.7 92.3 88.6 83.3 74.5 93.9 94.7 75.7 76.5
107
a Reference 6. b Plant operated with two trickling filters in series. c BOD is the 5-day biological oxygen demand and TSS is total suspended 5 solids removal. P ) primary gravitational settling, AS ) activated sludge, C ) carousel, OD ) oxidation ditch, TF ) trickling filter, RBC ) rotating biological contactor, L ) lagoon.
tetramethyl-1H-3a,7-methanoazulen-5-yl)ethan-1-one), AHTN (7-acetyl-1,1,3,4,4,6,-hexamethyl-1,2,3,4-tetrahydronaphthalene), and HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-[gamma]-2-benzopyran) (6). In brief, hourly samples of influent, primary effluent, and final effluent were collected from wastewater treatment plants over several days, using an ISCO autosampler (6). Samples were immediately preserved with 3% formalin (by volume) (6). Because FM influent concentrations follow a diurnal cycle (6), samples were composited, based on hourly plant flow, into daily samples. The daily samples were composited (based on daily plant flow) into samples which represented the entire sampling period. Nine perdeuterated FMs (d3-terpineol, d3benzyl acetate, d3-g-methyl ionone, d3-methyl dihydrojasmonate, d3-OTNE, d4-acetyl cedrene, d6-musk xylene, d3AHTN, and d7-musk ketone) were used as internal standards and were added to the samples prior to extraction (6). A high flow C18 speed disk was used to extract FMs from wastewater (0.5 L) and treated wastewater (1 L), and gas chromatographic mass spectrometry, with selected ion monitoring, was used for identification and quantitation (6). Method blanks and analyte recoveries were determined with every batch of samples processed. Blank concentrations (0-32 ng/L, depending on the analyte) and analyte recoveries (97-115%, 2840
9
ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 36, NO. 13, 2002
TABLE 3. Average, Standard Deviation, and Results from a Two-Sample Student’s t-Test of FM Concentration (µg/L) in U.S. Influent (n ) 12) and European Influent (n ) 5) fragrance material
U.S. av ( SD
Europe av ( SD
t-test p < 1%?
benzyl acetate methyl salicylate methyl dihydrojasmonate terpineol benzyl salicylate isobornyl acetate g-methyl ionone p-t-bucinal musk ketone musk xylene hexylcinnamaldehyde hexyl salicylate OTNE acetyl cedrene AHTN HHCB
3.74 ( 3.46 10.2 ( 9.69 7.21 ( 4.19 63.7 ( 36.4 19.5 ( 10.8 6.47 ( 8.53 3.37 ( 2.56 1.61 ( 0.731 0.640 ( 0.395 0.386 ( 0.299 15.3 ( 12.1 5.48 ( 3.56 3.55 ( 1.93 4.97 ( 2.27 12.5 ( 7.35 16.6 ( 10.4
9.85 ( 10.2 11.3 ( 13.0 11.9 ( 5.31 56.3 ( 33.9 10.2 ( 4.51 37.1 ( 28.4 3.63 ( 1.90 2.56 ( 1.96 0.996 ( 0.741 0.248 ( 0.136 12.8 ( 7.27 6.89 ( 3.63 9.00 ( 3.77 7.15 ( 4.32 5.97 ( 3.88 9.71 ( 5.09
no no no no no yes no no no no no no yes no no no
depending on the analyte) were similar to what we have previously reported (6). Site Selection. The location, type of treatment, sampling dates, plant flow, and 5-day Biological Oxygen Demand (BOD)
FIGURE 1. Average relative profile and standard deviation of FMs in (A) influent and (B) primary effluent in the U.S. and Europe. The highest concentration FM was normalized to 1. Actual concentrations are given in Table 3, and the highest concentration fragrance material (in µg/L) is in parentheses in Figure 1. The error bars represent the normalized standard deviation of the mean. and total suspended solids (TSS) removal for each of the wastewater treatment plants sampled are described in Table 2. Samples were collected between September 1997 and September 2000. Of the 17 different plants sampled, 12 were located in the U.S. and five were located in Europe. Four of the 17 plants, the two oxidation ditch and the two lagoon plants, had no primary treatment. Plants were selected based on the type of treatment, geographic location, and percent industrial contribution to flow (less than 20%). Several of these plants have been previously used to measure the removal of surfactants during wastewater treatment (26, 27). In the U.S., approximately 81% of the flow to wastewater treatment plants is treated by activated sludge plants, 7% by trickling filter, 6% by lagoon, 3% by oxidation ditch, 2% by rotating biological contactor, and 1% by primary treatment (25). The degree and type of wastewater treatment in Europe varies greatly. Activated sludge, carousel, trickling filter, and oxidation ditch are among the most common types of wastewater treatment in Europe (26).
Results and Discussion These data can be used to investigate the potential role of geography (U.S. or Europe) and plant design and operation on FM concentration and removal during wastewater treatment. While the concentration and relative profile of FMs in influent is primarily a function of geography (the volume of the FM used and the per capita water use in the geography), the concentrations and profile of FMs in primary effluent and final effluent are a function of geography as well as plant design and operation (degree of removal due to biodegradation, sorption, and/or volatilization). A comparison of the percent removal of FMs during treatment, across different plant types, eliminates differences due to geography and highlights differences in plant design and operation. Influent and Primary Effluent. Because of potential differences in U.S. and European industry volume and per capita water use, it was possible that the concentrations and relative profiles of FMs in U.S. and European influent would be significantly different. However, the concentration and VOL. 36, NO. 13, 2002 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
9
2841
FIGURE 2. Average relative profile and standard deviation of FMs in final effluent in U.S. and European plants. The highest concentration FM was normalized to 1. Actual concentrations are given Table 4, and the highest concentration fragrance material (in µg/L) is in parentheses in Figure 2. The error bars represent the normalized standard deviation of the mean. relative profiles are quite similar (Table 3 and Figure 1A). (Figures 1 and 2 show the relative profile of FMs after normalizing the highest concentration FM to 1. The actual concentrations are given in Tables 3 and 4.) The FMs with statistically different U.S. and European influent concentrations were isobornyl acetate and OTNE. In both cases, the average European influent concentration was greater than the average U.S. influent concentration. In both U.S. and 2842
9
ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 36, NO. 13, 2002
European influent, musk xylene was measured in the lowest average concentrations (0.386 and 0.248 µg/L, respectively), and terpineol was measured in the highest average concentration (63.7 and 56.3 µg/L, respectively). Other sources of terpineol that contribute to the high concentration in influent include use as flavorings and solvents (6, 30). The large standard deviations of the average influent concentrations (Table 3) indicate that there is significant variability in
TABLE 4. Final Effluent Concentration of Fragrance Materials (in ng/L) by Type of Wastewater Treatment and Geographya
fragrance material
P + AS U.S. n)4 Europe av ( SD n)1
benzyl acetate
49 ( 34
100
methyl salicylate
21 ( 17
310
107 ( 18
26
terpineol
51 ( 54
220
benzyl salicylate
91 ( 50
40
isobornyl acetate
17 ( 7
10
g - methyl ionone
66 ( 109
420
p - t - bucinal
35 ( 10
80
musk ketone
58 ( 28
60
musk xylene
10 ( 4
10
hexylcinnamaldehyde
10 ( 5
70
9(4
20
methyl dihydrojasmonate
hexyl salicylate OTNE
159 ( 117
3190
acetyl cedrene
176 ( 150
680
AHTN
1326 ( 270
1440
HHCB
2053 ( 1314
4620
P+C Europe n)2 av (range)
OD (no P) U.S. n)2 av (range)
P + TF U.S. n)3 av ( SD
Europe n)2 av (range)
80 99 252 ( 155 165 (60, 100) (95, 103) (70, 260) 130 32 693 ( 641 80 (40, 220) (22, 42) (70, 90) 1230 168 456 ( 210 1015 (1160, 1300) (3, 332) (110, 1920) 95 30 1079 ( 693 7605 (80, 110) (17, 42) (110, 15100) 665 82 1025 ( 1240 990 (590, 740) (76, 88) (20, 1960) 140 45 112 ( 94 165 (70, 210) (24, 65) (40, 290) 220 29 214 ( 191 380 (190, 250) (26, 31) (30, 730) 80 45 258 ( 237 110 (70, 90) (41, 48) (40, 180) 705 ND 67 ( 27 120 (640, 770) (40, 200) 10 10 112 ( 172 95 (10, 10) (6, 14) (20, 170) 170 15 77 ( 64 465 (170, 170) (10, 19) (20, 910) 100 10 243 ( 353 460 (70, 130) (3, 17) (10, 910) 1470 82 615 ( 252 1700 (1240, 1700) (53, 110) (490, 2910) 80 76 1359 ( 1654 830 (70, 90) (59, 93) (230, 1430) 1235 1010 1555 ( 522 1645 (1170, 1300) (890, 1130) (620, 2670) 1065 1495 2056 ( 655 2400 (980, 1150) (1490, 1500) (1050, 3750)
L (no P) P + RBC U.S. U.S. n)2 av (range) n)1 86 318 14 105 123 41 34 107 55 32 17 1* 217 495 1710 2210
3* (2, 3) 64 (13, 115) 75 (64, 85) 25 (11, 38) 31 (5, 57) 11 (7, 15) 26 (7, 44) 21 (13, 28) 19 (10, 27) 1* (0, 1) 12 (10, 14) 14 (7, 21) 28 (25, 31) 95 (12, 178) 77 (24, 130) 53 (32, 73)
a Asterisks indicate that the value is at the limit of quantitation for the analytical method (6). ND ) not determined; matrix interferences did not allow for accurate determination of the concentration in final effluent. P ) primary gravitational settling, AS ) activated sludge, C ) carousel, OD ) oxidation ditch, TF ) trickling filter, RBC ) rotating biological contactor, L ) lagoon.
influent concentrations within both the U.S. and European plants. Figure 1A and Table 3 show that the U.S. and European influent concentrations of the nitromusks, musk ketone and musk xylene, and the PCMs, AHTN and HHCB, are similar and are used in the same relative amounts by both U.S. and European consumers. This indicates that the use volumes of AHTN and HHCB are greater than musk ketone and musk xylene use volumes in the U.S. and Europe. Our measured concentrations of AHTN, HHCB, musk ketone, and musk xylene in Europe are similar to previously reported concentrations (21, 23). Figure 1B shows the average relative profile of the FMs in U.S. and European effluent from primary treatment. By comparing Figure 1A,B, it is clear that the relative profile of FMs does not change significantly between influent to the wastewater treatment plant and primary effluent. The primary effluent profile is also dominated by terpineol and has very low relative amounts of the nitro musks. However, the average concentration of FMs is reduced in primary effluent by 1450% due to significant removal during this treatment step (Table 5). Typically, sorption and settling of solids play a major role in the removal of chemicals from primary treatment. However, we measured significant removal of both sorptive and nonsorptive FMs during primary treatment (comparison of Kd value in Table 1 and the percent primary removal in Table 5). This indicates that, for some FMs, such as benzyl acetate, methyl salicylate, methyl dihydrojasmonate, and terpineol, biodegradation plays a role in their removal during primary treatment. Finally, the large standard
deviations of the average percent primary removal (Table 5) indicate that there is significant plant to plant variability in the removal of FMs during this treatment step. Final Effluent and Overall Removal. Figure 2 shows the average, normalized profile of FMs in final effluent (effluent from secondary treatment), with the highest concentration FM in parentheses (in µg/L). The concentrations are given in Table 4. Clearly, the average relative profile of FMs changes significantly between primary effluent (Figure 1B) and final effluent (Figure 2). A major difference is that, excluding the European trickling filter effluent, the final effluent profiles are not dominated by terpineol. In five of the eight combinations of plant type and geography, the final effluent profile is dominated by HHCB. In the activated sludge (U.S. and European plants), rotating biological contactor, and oxidation ditch plants, the average relative profile of FMs in final effluent is enriched in the nonbiodegradable, sorptive FMs (such as AHTN and HHCB). These types of plants are known for being efficient at removing biodegradable chemicals (26-27). In carousel, lagoon, and trickling filter plants, the average FM profile in final effluent was enriched in both the biodegradable, nonsorptive FMs (such as methyl dihyrdojasmonate, terpineol, and benzyl salicylate) and the nonbiodegradable, sorptive FMs (such as AHTN and HHCB). The overall removal (primary + secondary treatment) of FMs ranged from 87.8 to 99.9% for activated sludge plants, 58.6-99.8% for carousel plants, 88.9-99.9% for oxidation ditch plants, 71.3-98.6% for trickling filter plants, 80.8-99.9% for a rotating biological contactor plant, and 96.7-99.9% for VOL. 36, NO. 13, 2002 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
9
2843
TABLE 5. Percent Removal of FMs by Type of Wastewater Treatmenta P only n ) 13 av ( SD
P + AS n)5 av ( SD
P+C n)2 av (range)
OD (no P) n)2 av (range)
P + TF n)5 av ( SD
P + RBC n)1
benzyl acetate
28.2 ( 27.5
95.2 ( 7.1
98.3
40.4 ( 32.2
99.6 ( 0.3
92.0 ( 5.1
95.7
methyl dihydrojasmonate
14.6 ( 19.4
98.2 ( 0.8
93.1 ( 3.7
99.9
terpineol
15.5 ( 12.0
99.9 ( 0.1
95.4 ( 5.6
99.9
benzyl salicylate
41.8 ( 25.0
99.5 ( 0.5
94.9 ( 4.6
98.6
isobornyl acetate
29.0 ( 29.5
99.6 ( 0.4
96.8 ( 2.0
98.7
g-methyl ionone
20.8 ( 19.6
96.5 ( 4.4
87.7 ( 16.8
98.4
p-t-bucinal
50.6 ( 23.4
96.1 ( 3.5
94.8 ( 2.9
94.8
musk ketone
26.6 ( 21.5
91.0 ( 5.2
87.8 ( 4.6
85.2
musk xylene
41.2 ( 21.9
97.8 ( 1.0
87.6 ( 14.2
89.1
hexylcinnamaldehyde
47.1 ( 19.4
99.8 ( 0.1
98.6 ( 1.7
99.8
hexyl salicylate
37.3 ( 21.0
99.8 ( 0.1
96.4 ( 4.0
99.9
OTNE
28.8 ( 22.7
91.7 ( 10.0
80.0 ( 16.3
90.7
acetyl cedrene
31.6 ( 20.3
95.1 ( 4.4
71.3 ( 40.5
87.7
AHTN
28.9 ( 20.1
88.8 ( 6.3
81.0 ( 5.7
81.7
HHCB
29.9 ( 23.4
87.8 ( 7.9
95.5 (94.8, 96.1) 99.3 (99.2, 99.3) 97.9 (95.7, 99.9) 99.9 (99.9, 99.9) 99.7 (99.4, 99.9) 92.0 (84.5, 99.4) 98.7 (98.2, 99.1) 96.2 (94.8, 97.6) 93.1 (91.0, 95.2) 97.3 (96.7, 97.8) 99.9 (99.8, 99.9) 99.8 (99.7, 99.9) 96.6 (95.1, 98.1) 98.0 (97.5, 98.5) 88.9 (86.9, 90.8) 89.6 (86.1, 93.0)
86.4 ( 7.4
methyl salicylate
98.9 (98.6, 99.1) 98.7 (97.8, 99.5) 82.5 (81.9, 83.1) 99.6 (99.4, 99.6) 91.1 (90.3, 91.9) 99.8 (99.6, 99.9) 87.1 (83.1, 91.1) 85.9 (84.8, 86.9) ND
78.1 ( 8.7
80.8
fragrance material
89.3 (87.9, 90.6) 96.3 (95.3, 97.3) 97.3 (96.0, 98.5) 66.0 (51.4, 80.5) 97.7 (96.9, 98.5) 58.6 (50.6, 66.6) 73.5 (63.5, 83.4)
L (no P) n)2 av (range) 99.9 (99.9, 99.9) 99.5 (99.0, 99.9) 99.0 (98.9, 99.1) 99.9 (99.9, 99.9) 99.9 (99.8, 99.9) 99.9 (99.9, 99.9) 99.3 (98.8, 99.8) 98.3 (97.2, 99.3) 96.7 (96.6, 96.7) 99.5 (99.1, 99.9) 99.9 (99.8, 99.9) 99.7 (99.4, 99.9) 99.2 (99.0, 99.4) 98.5 (97.0, 99.9) 99.3 (98.7, 99.9) 99.7 (99.7, 99.7)
a ND ) not determined; matrix interferences did not allow for accurate determination of the concentration in final effluent. P ) primary gravitational settling, AS ) activated sludge, C ) carousel, OD ) oxidation ditch, TF ) trickling filter, RBC ) rotating biological contactor, L ) lagoon.
lagoons (Table 5). The standard deviations of the overall removal (primary and secondary treatment) of FMs were much lower than the standard deviations of the primary removal (Table 5), suggesting that, for a given plant type, the secondary treatment process compensates for variability in the primary treatment process. The average concentration of FMs in final effluent ranged from the limit of quantitation (1-3 ng/L) to 8 µg/L (Table 4). The simplest form of treatment, lagoon, resulted in the most effective removal of FMs, with removals in the range of 96.7-99.9% (Table 5). This is likely due to the long retention times (90-120 days), with sufficient time for biodegradation, photodegradation, sorption and settling, and/or volatilization from the lagoons. The concentration of FMs in final effluent from lagoons ranged from the limit of quantitation to 95 ng/L and were, in general, the lowest final effluent concentrations measured in the study (Table 4). Table 2 shows that, depending on plant design and operation, there were significant differences in plant 5-day Biological Oxygen Demand (BOD) and Total Suspended Solids (TSS) removal. We investigated the relationship of plant design and operation, as measured by plant BOD and TSS removal, with the overall plant removal of FMs. Although not all correlations were significant, we found a general trend that overall removal of biodegradable, nonsorptive FMs was positively correlated with plant BOD removal and that overall removal of nonbiodegradable, sorptive FMs was positively correlated with plant TSS removal. This is consistent because BOD removal is dependent on the efficiency of biodegradation in the plant and TSS removal is dependent on the efficiency of solids settling in the plant. Lagoons were the only plant design that did not follow this trend because they 2844
9
ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 36, NO. 13, 2002
FIGURE 3. Correlation of the measured overall removal of terpineol with plant 5-day BOD removal and the measured overall removal of HHCB with plant TSS removal. Regressions include all wastewater treatment plants except the two lagoon (see text) and are significant at the 99.9% level; n ) 15. Dashed lines are the 95% confidence intervals of the regressions. had poor BOD and TSS removal (Table 2), due to aquatic vegetation growing in the lagoons, but had good removal of FMs (Table 5). As an example, Figure 3 shows the statistically significant correlation (99.9% level) of terpineol removal with plant BOD removal and HHCB removal with plant TSS removal for all treatment types, excluding the two lagoon plants. Comparison to Removals and Concentrations Predicted by Framework. Recently, a framework document was developed to prioritize the over 2100 fragrance materials in
FIGURE 4. Correlation of (A) measured primary removal with predicted primary removal (24) and (B) measured overall removal with predicted overall removal for activated sludge plants, using the second tier of the framework model and accounting for sorption and biodegradation (24). All activated sludge plants are included in (B), and the error bars represent the standard deviation of the mean. The regression for overall removal (B) is significant at the 98% level, while the regression for primary removal (A) is not statistically significant; n ) 16. Dashed lines are the 95% confidence intervals of the regressions. commerce for aquatic risk assessment (24). An integral part of the aquatic risk assessment is an accurate prediction of exposure in the aquatic compartment. To do this, the annual volume of use and the per capita water use in the geography are used to predict an average influent concentration for the U.S. and Europe. Next, the FM removal during primary treatment (sorption and settling) is predicted using the octanol-water partition coefficient and the average primary removal and effluent concentration is predicted. Finally, the FM removal during secondary treatment and final effluent concentrations are predicted in the first tier of the framework using the octanol-water partition coefficient to estimate sorption and biodegradation rates are added in the second tier of the framework if a more refined exposure assessment is needed. Readily biodegradable, inherently biodegradable, and nonbiodegradable FMs are assumed to have biodeg-
radation rates of 3 h-1, 0.3 h-1, and 0 h-1, respectively (24, 31). This simple model does not account for volatilization and the assumptions and equations in the framework document are directly applicable to all primary treatment but only to activated sludge secondary treatment (24). The largest single source of error in the model is likely the estimation of annual volume use because of uses outside the fragrance industry and, in some cases, natural sources (30). Because of the large number of FMs being evaluated and the wide range of physical chemical properties and biodegradabilities they represent, it is important to determine if the assumptions made in the framework document are conservative. Figure 4 A shows the regression of the measured percent primary removal (Table 5) with the percent primary removal predicted by the framework (24). All of the plants with primary treatment are included in this regression. VOL. 36, NO. 13, 2002 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
9
2845
FIGURE 5. Comparison of measured FM concentrations in all plants to predicted FM concentrations in the U.S. and Europe (24) for (A) influent, (B) primary effluent, (C) final effluent using the first tier (sorption only) of the framework, and (D) final effluent using the second tier (sorption and biodegradation) of the framework. Points above the line have measured values greater than predicted by the framework model (24), while those below the line have measured values less than predicted. The filled circles represent concentrations in the U.S., and the open circles represent concentrations in Europe. Because of the large variation in measured primary removal (Table 5), the correlation is not statistically significant. Also, the framework prediction does not account for potential biodegradation during primary treatment, and we measured significant removal of biodegradable, nonsorptive FMs during primary treatment (Table 5). Figure 4B shows the regression of the measured percent overall removal from activated sludge treatment plants only (Table 5) with the percent overall removal predicted by the second tier of the framework (accounting for sorption and biodegradation) for activated sludge plants (23). This correlation is significant at the 98% level; however, the framework significantly underpredicts overall removal (slope ) 0.118). This is particularly true for musk ketone, musk xylene, OTNE, AHTN, and HHCB which are assumed to be nonbiodegradable (Table 1) and to have biodegradation rates of 0 h-1. This suggests that sorption alone does not account for the removals we have measured for musk ketone, musk xylene, OTNE, AHTN, and HHCB and that biotransformation (2, 32) and/or volatilization may be playing a major role in the removal of these FMs from activated sludge. Because the framework assumptions and equations are specific to activated sludge treatment, we wanted to determine if the assumptions were conservative for all of the plant designs we have investigated. Figure 5 shows the comparison of our measured concentrations with the predicted concentrations (24) of the 16 FMs in influent (Figure 5A), primary effluent (Figure 5B), final effluent using the first tier (sorption only) of the framework (Figure 5C), and final effluent using the second tier (sorption and biodegradation) of the framework (Figure 5D) for all of the wastewater treatment plants we sampled in the U.S. and Europe. Figure 5A indicates that the measured influent concentration is sometimes greater than the predicted influent concentration in the U.S. and Europe (points above the 1:1 line). This may be because the annual usage has been underestimated because of unac2846
9
ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 36, NO. 13, 2002
counted for uses in flavorings (30) and natural sources. Figure 5B indicates that, for some FMs, the underestimation of influent concentration results in an underestimation of primary effluent concentration. However, Figure 5C shows that the first tier of the framework model (accounting for sorption only) is conservative and overpredicts the most important concentration, final effluent concentration, for all plant designs in both the U.S. and Europe. Finally, Figure 5D shows the second tier of the framework model (accounting for sorption and biodegradation) is conservative for 96% of the final effluent concentrations measured in this study. Eleven of the 272 measured final effluent concentrations exceed the concentrations predicted by the second tier of the framework model. These 11 data points can be explained by (1) underestimation of annual usage due to other uses, such as solvents and pharmaceuticals (30) (terpineol and methyl salicylate final effluent concentrations in the U.S. and Europe account for nine of the 11 outliers) and (2) less than predicted removal due to poor operation of the Sedalia and Stretford trickling filter plants (Table 2) (hexyl salicylate and benzyl salicylate final effluent concentrations at these two plants account for two of the 11 outliers). It is important to note that, although the assumptions and equations in the framework document are applicable to activated sludge wastewater treatment, the end result is a predicted final effluent concentration that is generally greater than we have measured at many different plant types in the U.S. and Europe. These data show that the assumptions made in the framework document to predict final effluent concentrations, and ultimately aquatic exposure concentrations, are conservative.
Acknowledgments The authors would like to thank Dan Salvito of the Research Institute for Fragrance Materials Inc. for generating Figure 5.
Literature Cited (1) Herren, D.; Berset, J. D. Chemosphere 2000, 40, 565-574. (2) Rimkus, G. G.; Gatermann, R.; Huhnerfuss, H. Tox. Lett. 1999, 111, 5-15. (3) Ranke, S.; Meyer, C.; Heinzel, N.; Gatermann, R.; Huhnerfuss, H.; Rimkus, G.; Konig, W. A.; Francke, W. Chirality 1999, 11, 795-801. (4) Winkler, M.; Headley, J. V.; Peru, K. M. J. Chromatogr. A 2000, 903, 203-210. (5) Aschmann, S. M.; Arey, J.; Atkinson, R.; Simonich, S. L. Environ. Sci. Technol. 2001, 35, 3595-3600. (6) Simonich, S. L.; Begley, W. M.; Debaere, G.; Eckhoff, W. S. Environ. Sci. Technol. 2000, 34, 959-965. (7) Fromme, H.; Otto, T., Pilz, K.; Neugebauer, F. Chemosphere 1999, 39, 1723-1735. (8) Fromme, H.; Otto, T.; Pilz, K. Water Res. 2001, 35, 121-128. (9) Rimkus, G. G. Tox. Lett. 1999, 111, 37-56. (10) Standley, L. J.; Kaplan, L. A.; Smith, D. Environ. Sci. Technol. 2000, 34, 3124-3130. (11) Verbruggen, E. M. J.; Van Loon, W. M. G. M.; Tonkes, M.; Van Duijn, P.; Seinen, W.; Hermens, J. L. M. Environ. Sci. Technol. 1999, 33, 801-806. (12) Juttner, F. Water Sci. Technol. 1999, 40, 123-128. (13) Kallenborn, R.; Gatermann, R.; Planting, S.; Rimkus, G. G.; Lund, M.; Schlabach, M.; Burkow, I. C. J. Chromatogr. A 1999, 846, 295-306. (14) Behechti, A.; Schramm, K. W.; Attar, A.; Niederfellner, J.; Kettrup, A. Water Res. 1998, 32, 1704-1707. (15) Giddings, J. M.; Salvito, D.; Putt, A. E. Water Res. 2000, 34, 36863689. (16) Schramm, K. W. Water Res. 2000, 34, 2626. (17) Chou, Y. J.; Dietrich, D. R. Tox. Lett. 1999, 111, 17-25. (18) Chou, Y. J.; Dietrich, D. R. Tox. Lett. 1999, 111, 27-36.
(19) Seinen, W. Lemmen, J. G.; Pieters, R. H. H.; Verbruggen, E. M. J.; van der Burg, B. Tox. Lett. 1999, 111, 161-168. (20) Schwartz, S.; Berding, V.; Matthies, M. Chemosphere 2000, 41, 671-679. (21) Balk, F.; Ford, R. A. Tox. Lett. 1999, 111, 57-79. (22) Balk, F.; Ford, R. A. Tox. Lett. 1999, 111, 81-94. (23) Tas, J. W.; Balk, F.; Ford, R. A.; van de Plassche, E. J. Chemosphere 1997, 35, 2973-3002. (24) Salvito, D. T.; Senna, R. J.; Federle, T. W. Environ. Tox. Chem. in press. (25) 1996 Clean Water Needs Survey, Report to Congress, September 1997; EPA #832/R-97-003. (26) Matthijs, E.; Holt, M. S.; Kiewiet, A.; Rijs, G. B. J. Environ. Tox. Chem. 1999, 18, 2634-2644. (27) McAvoy, D. C.; Dyer, S. D.; Fendinger, N. J.; Eckhoff, W. S., Lawrence, D. L.; Begley, W. M. Environ. Tox. Chem. 1998, 17, 1705-1711. (28) RIFM/FEMA Database, 2001. Research Institute of Fragrance Materials, Hackensack, NJ 07601. (29) Meylan, W. M.; Howard, P. H. Chemosphere 1993, 26, 22932299. (30) Somogyi, L. Aroma chemicals and the flavor and fragrance industry. In Chemical Economics Handbook; Stanford Research Institute: Menlo Park, CA, 1998. (31) Struijs, J.; van den Berg, R. Water Res. 1995, 29, 255-262. (32) Federle, T. W. The Procter and Gamble Company, unpublished data.
Received for review January 2, 2002. Revised manuscript received April 19, 2002. Accepted April 24, 2002. ES025503E
VOL. 36, NO. 13, 2002 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
9
2847
