(6) “Biologic Effects of Atmospheric Pollutants-Particulate Polycyclic Organic Matter”. National Academy of Sciences, LVashington. D.C.. 1972. (7) Strup, P. E., Giammar. R. D., Stanford, T. B., Jones, P. W., in “Carcinogenesis--A Comprehensive Survey”, Freudenthal. R. I., ,Jones. P.:Eds., Raven Press, New York, 1976, pp 241-51. (8) Nau, C. A,, paper presented at the Conference on Environmental Aspects of Chemical Use in Rubber Processing Operations, Akron, Ohio, March 12-~14,1975. (9) Neal, J., Thornton, M., Nau. C. A,, Arch. Enuiron. Health, 4,46 (1962).
(10) Nau, C. A.. Neal. .J.. Stembridge, V., Arch Ind Hyg , 17, 21 (1958). (11) Nau, C. A,. Neal, J., Stembridge, V., Arch Ind H ->.,g , 18.. 511 (1958). (12) Xau. C. A,, Neal, J.. Stembridge, V., Arch. Ind. H y g . , 20, 512 (1960). (13) Nau, C. A , , Neal, J., Stembridge, V., Cooley, R. N., Arch. Enuiron. H y g . , 4, 415 (1962). ~
Receiced for revieu: October 22, 1979. Accepted December 10, 1979.
An Environmental Safety Assessment of Butyl Benzyl Phthalate William E. Gledhill”, Robert G. Kaley, William J. Adams, Orville Hicks, Paul R. Michael, and Victor W. Saeger Monsanto Company, 800 N. Lindbergh Boulevard, St. Louis, Mo. 63166
Gerald A. LeBlanc EG&G Bionomics, Wareham, Mass. 0257 1
T h e current environmental safety assessment concludes that, under present use/disposal patterns, butyl benzyl phthalate (BBP) does not constitute a hazard t o the aquatic environment. B B P is relatively insoluble in water and tends t o partition to soil. sediment, and biota in the aqueous environment. Biodegradation, the controlling rate process for environmental degradation of BBP, is rapid and extensive in natural water and sewage systems. Environmental levels of BBP averaged less than 1 pg/L in water and less than 100 ng/g in sediment. B B P is acutely toxic to a variety ofalgae, invertebrates, and fish in the 0.5-5 mg/L range and chronically toxic to D a p h n m and fathead minnows in the 0.1-0.8 mg/L range. A bioconcentration study indicated t h a t B B P was not an accumulative or persistent chemical in fish. Comparison of mean environmental water concentrations of B B P to laboratory chronic toxicity values for D a p h n i a and fathead minnows showed an average safety margin of approximately three orders of magnitude. Butyl benzyl phthalate (BBP), manufactured by Monsanto 0
of ten classes of chemicals, including alkyl phthalates, by the Interagency Testing Committee ( I ) as materials needing priority testing. The Clean Water Act (CWA) of 1977 translated much of the Consent Decree into statutory law. Both the EPA-NRDC Consent Decree and the C W A specifically require t h a t water quality criteria be established for phthalate esters. In meeting these requirements the EPA has initially selected six phthalate esters, one of which is BBP, on which t o develop criteria. Currently, insufficient published information is available to make a n adequate safety evaluation of BBP. Opportunity exists for the release of B B P to the environment from manufacture, distribution, PVC blending operations, and consumer use of finished products. However, because of the low rate of diffusion of BRP from consumer products (2),we believe only a small percentage of the B B P produced actually enters the environment. This research project was designed to evaluate the environmental safety of BBP. Results of both laboratory and field studies will be described. T h e current assessment will not address human health or wildlife effects. Phthalate esters are readily metabolized in mammalian systems and show low toxicity in acute, subacute, and chronic feeding studies ( 3 ) . Experimental
0
under the trade name Santicizerm 160, is produced in excess of 100 X IOfi lb annually and is used primarily to plasticize, or flexibilize, synthetic resins, chiefly poly(viny1 chloride) (PVC). T h e major use of B B P is in the production of flooring materials with smaller amounts also occurring in other household products. T h e functionality of B B P results from its high compatibility with PVC and other resin systems a n d is attributable to BBP’s unique molecular structure. T h e polar carbonyl and aromatic groups interact strongly with polar chloromethine groups of PVC and the various oxygen-containing functional groups of cellulosic and acrylic resins. T h e alkyl group of BBP contributes to the flexibility and resistance t o aqueous extractability of plasticized resins. The environmental safety of phthalate esters has recently drawn national attention as a result of the 1976 Consent Decree settlement (of a lawsuit by the Natural Resources Defense Council (NRDC) e t al. against the Environmental Protection Agency (EPA) over implementation of the Federal Water Pollution Control Act. This action resulted in the designation 0013-936X/80/0914-0301$01.00/0 @ 1980 American
Chemical Society
Materials. Commercial grade B B P was used throughout these studies, except for the microcosm study which used ~ a r b o n y l - ~ ~ C - l a b eBl eBdP (specific activity of 6.35 pCi/g). Both products were synthesized by Monsanto Company. Purified water for aqueous solubility, octanol/water partition coefficient, soil adsorption, and photodegradation studies was obtained from a Milli-Q water purification system (Millipore Corp., Bedford, Mass.). Pesticide grade organic solvents were used for all extractions and dilutions. Analytical Methods. Extraction of the aqueous samples from the mobility tests involved addition of 10.0 m L of the centrifuged solution to a 4-dram vial along with 1.0 m L of hexane. T h e vial was sealed with a n aluminum foil lined cap and shaken for 2 min. Extraction of water from the environmental samples was accomplished with three 100-mL aliquots of methylene chloride. Extracts were passed through a 1-in. layer of NaC1 and a 2-in. layer of Na2SO4 and concentrated in a Kuderna-Danish evaporative concentrator. Sediment samples were homogenized before extraction. A 10-g aliquot (wet weight) was supplemented with 30 g of NaZS04 to absorb excess moisture and extracted in triplicate with 50 mL of methylene chloride using a PolytronB Ultrasonic Homogenizer Volume 14, Number 3, March 1980 301
(Brinkman Instrument Co.). Extracts were combined and concentrated prior t o analysis. Concentrated extracts from laboratory studies were analyzed by gas chromatography using a Hewlett-Packard 5730 chromatograph equipped with a flame ionization or electron-capture detector. Samples were injected onto a 1m or 2 m X 3 mm i.d. glass column packed with 3% OV-101 on 100/120 Gas-Chrom Q (column temperature 230 "C). Concentrated extracts from the environmental sampling study were analyzed by means of a Hewlett-Packard 5982A gas chromatography/mass spectrometry system with a 5934A data system in the selected ion monitoring mode. T h e column was programmed from 100 to 290 "C a t 16 OC/min, and m / e 91 and 149 were monitored at ions characteristic of BBP. The methods were validated by dosing known amounts of B B P into water and sediment samples a t two concentrations each. T h e percent recovery for water dosed at 2 and 10 pg/L averaged 104.6% (96-112%). Recovery for sediment dosed a t 0.2 and 1.0 pg/g averaged 92.3% (86-100%). Mobility Tests. Aqueous solubility was determined by slowly stirring 1 mL of B B P with 500 m L of water in an enclosed container a t ambient temperature (20 f 2 OC). The aqueous phase was sampled over a period of 3 weeks until equilibrium was reached. Preparation of samples for gas chromatographic analysis and the methodology for determining the octanol/water partition coefficient have been described previously ( 4 ) .The bioconcentration factor for rainbow trout was calculated from the partition coefficient using the equation of Neely e t al. ( 5 ) . The soil adsorption study was conducted using a batch technique similar to that recommended by the Environmental Protection Agency for the premanufacture testing of new chemical substances (6, p 16257). Three different soils were used with organic matter ranging from 1.2 to 3.4%. BBP was added as a concentrated methanol solution t o give a n initial concentration in water ranging from 0 to 1 mg/L. Water/soil mixtures were shaken for 24 h and then centrifuged. The aqueous phase was analyzed for BBP, and the amount adsorbed to the soil was calculated by difference. T h e soil partition coefficient was calculated as the ration of BBP adsorbed to the soil to that remaining in the water. Persistence Tests. Biodegradation Screening. T h e semicontinuous activated sludge (SCAS), carbon dioxide evolution, and river die-away (RDA) methods were those described by Saeger and Tucker ( 7 ) .Anaerobic biodegradation was assessed using the procedure of Healy and Young (8) and modifications described by Gledhill (9). Photodegradation. The general procedure followed in the photodegradation screening is similar to that described by the EPA (6, p 16271) using sunlight exposure to aqueous solutions of B B P in sealed tubes. The tubes used in the study were 13-mm 0.d. quartz tubes reduced to a short section of 8-mm tubing a t the open end. The overall volume of the tubes was about 11 mL. The tubes were sealed with Chemplast TaperTite Teflon connectors and short lengths of 8-mm glass rod. A platform capable of holding 132 tubes was constructed from three 6-ft lengths of aluminum bar stock (1 in. X 0.5 in.). Tubes were positioned on the bar a t a 60" angle to the horizon. For the study, 14 tubes were filled with 10 m L of a 1-mg/L BBP solution. The tubes were analyzed in duplicate according to the following sunlight exposure schedule: 0,2,4,10,17,and 28 days. Two tubes, wrapped in black polyethylene film, served as dark controls and were analyzed a t the last sampling point. For analysis, 1 mL of hexane was pipetted quantitatively into the tube. A 20-mm 0.d. glass bulb (approximate volume of 15 mL) with a section of 8-mm tubing a t the open end was tightly connected to the quartz tube. T h e aqueous solution and hexane were shaken down into the larger bulb. 302
Environmental Science 8 Technology
After the mixture was vigorously shaken for 1 min, it was returned to the quartz tube where the phases were allowed to separate. The quartz tube was then tightly stoppered and refrigerated until the appropriate time for GC analysis of the hexane phase. The sunlight exposures took place in St. Louis on the 28 days between August 20 and September 17,1979. Microcosm. A microcosm simulating a lake environment was constructed using a 5-gal aquarium and the core-chamber technique described by Bourquin et al. (20). Water and sediment were collected from the littoral region of a spring-fed freshwater lake (Lake 34, Busch Wildlife Area, St. Charles County, Mo.). The sediment was screened through a steel screen (0.5-in. mesh) to remove large particulates. The bottom of the aquarium was covered with a %-in. Teflon sheet fitted with 8 evenly spaced No. 7 silicone stoppers. Four liters of sediment and 12 L of lake water were then added to the aquarium. The microcosm was then allowed to stabilize for a period of 6 weeks with gentle aeration and a 16/8 h light/dark cycle using 300-ft-c G E Daylight fluorescent lights. At the end of the stabilization period, the core chambers were created by inserting eight sterile glass cylinders (3.8 X 30 cm) through the water column and sediment onto the silicone stoppers. A Plexiglas template covering the top of the aquarium served as a guide for the coring process. Each chamber contained about 110 mL of lake water and 35 cm3 of sediment. Gas manifolds supplied either COz-free air or oxygen-free nitrogen just beneath the surface of each chamber. Gas flow was regulated by means of aquarium valves. Exhaust gas was passed through a Tenax-GC resin trap to remove volatilized organics and then through a COn scrubbing system containing 10 mL of 2-methoxyethanol-monoethanolamine solution (7:1, v/v). 14C-laheled B B P was added to the core chamber as an acetone solution (0.11 mg of BBP/20 p L of acetone) resulting in a final concentration of 1 mg/L. Samples of the water column were removed a t 0,3,7,14,21, and 28 days and analyzed for residual BBP and radioactivity. Ethanolamine traps were replaced according to the same schedule and the scrubber solutions were assayed for radioactivity. Tenax traps were removed a t the end of the 28-day test and eluted with acetone. Eluates were then assayed for radioactivity. E n v i r o n m e n t a l S a m p l i n g . Water and sediment samples were obtained during November 1977 and May 1978 from various industrialized and nonindustrialized locations (Table I). Water samples (900 mL), except those from San Francisco Bay, were drawn through a 50-ft Teflon tube into 1-L glass bottles by means of z 12-V vacuum pump. The Teflon line was cleaned with acetone between sampling stations. T h e water column was sampled by raising the Teflon line at a constant rate from the bottom t o the surface while the pump was operating. At least three and usually five samples were collected a t each location. The samples were collected in a straight-line traverse across each river and harbor. San Francisco Bay samples were grab samples of surface waters a t five locations. Sample bottles containing 100 mL of methylene chloride were sealed with a n aluminum foil lined cap and shaken for 1min in the field to extract and preserve the BBP. Sediment samples (100 g) were obtained with Ponar and Student-Ekman grab samplers. Three samples were taken from both sides and the middle of each river and harbor, wrapped in aluminum foil, placed in polyethylene containers, and stored on dry ice. They were subsequently transferred to a freezer (-10 O F ) and stored until analyzed. Aquatic Toxicity Tests. A c u t e L e t h a l i t y . Static acute toxicity tests were conducted with algae (Dunaliella t e r t iolecta, Microcystis aeruginosa, Navicula pelliculosa, Selen a s t r u m capricornutum, Sheletonema c o s t a t u m ) , water fleas (Daphnia m a g n a ) , mysid shrimp (Mysidopsis bahia), fathead ,
Table 1. Residues of BBP in Natural Water and Sediments av BBP concn a locatlon
collection dale
Waukegan Harbor, Ill
11/8/77
Waukegan Creek, Ill.
11/8/77
Upper Saginaw River, Saginaw, Mich. Lower Saginaw River, Bay City, Mich. Illinois River, Grafton, 111
11/10/77
Meramec River, Times Beach, Mo. Missouri River, St. Louis, Mo. Missouri River, Weldon Springs, Mo. Mississippi River North St. Louis, Mo. Mississippi River South St. Louis, Mo. San Francisco Bay (5 sites)
11/14/77
Table II. Parameters to Assess the Environmental Mobility of Butyl Benzyl Phthalate vapor pressure, 20 "C vapor pressure, 200 O C aqueous solubility, deionized water octanollwater partition coefficient calculated bioconcentration factor soil adsorption coefficient, measureda a
8.6 X IOp6 mmHg 1.9 mmHg 2.9 & 1.2 mg/L 5.9 f 4.3 x 104 510 68-350
Measured at 20 i. 2 O C .
11/10/77 11114177
1/16/77 1/16/77 1130177 5/23/78 1130177 5/23/78
*
a Average concentration of those samples containing BBP. Detection limit 0.2 pg/L. Detection limit 100 ng/g. Number of samples analyzed/number of samples containing measurable levels of BBP.
minnows ( P i m e p h a l e s p r o m e l a s ) , bluegills ( L e p o m i s m a crochirus), rainbow trout ( S a l m o gairdnerii), and sheepshead minnows ( C y p r i n o d o n cariegatus). Phytotoxicity tests followed the EPA algal assay procedure ( 1 1 ) . All acute toxicity tests followed the methods recommended for standardized laboratory toxicity tests (12). Waterflea tests were conducted in lake water a t 23 "C (hardness, 110 mg/L; alkalinity, 102 mg/L; p H 7.8). Units for hardness and alkalinity, mg/L, are actually expressed as mg/L as CaCO3. Rainbow trout, fathead minnows, and bluegills were tested in reconstituted soft water (hardness, 40 mg/L; alkalinity, 32 mg/L; pH 7.5) a t 1 2 and 22 "C, respectively. Fathead minnows were also tested a t a water hardness of 160 mg/L. Tests with mysid shrimp and sheepshead minnows were conducted a t 20 "C in natural seawater having salinities of 18 and 24 g/L, respectively. T i m e - I n d e p e n d e n t Toxicity. A time-independent flowthrough study ,with fathead minnows was conducted for 14 days in well water (hardness, 295 mg/L; alkalinity, 304 mg/L; p H 8.1; tempermature22 & 1 "C (dissolved oxygen, 60% saturation)). A continuous flow delivery system (13) with a peristaltic pump was used to deliver the water and chemical for five exposure levels, a control, and a solvent control. A constant amount of solvent (0.33 mL/L of dimethylformamide) was delivered to all test aquaria except the control. The test tanks were all-glass aquaria containing 15 L of test solution. Thirty fish (average weight 0.88 g) per aquarium were tested. A water flow rate of 6 L/h was maintained during the study period. Water samples for B B P analysis were collected five times during the study. T h e mean measured concentrations were 88.3% of nominal. T h e average ( & SD) l concentrations in the seven test aquaria were
