Saturation units for use in aquatic bioassays

Chemosphere, Vol.

39, No. 3, pp. 539-551, 1999 (¢) 1999 Elsevier Science Ltd. All rights reserved 0045-6535/99/$ - see front matter

Pergamon PIh S0045-6535(98)00604-3

SATURATION UNITS FOR USE IN AQUATIC BIOASSAYS

Michael D. Kahl*, Christine L. Russom, David L. DeFoe, Dean E. Hammermeister

U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division-Duluth, 6201 Congdon Boulevard, Duluth, MN 55804 (Received in USA 27 May 1998; accepted 27 November 1998)

ABSTRACT

Methods were developed for preparing liquid/liquid and glass wool column saturators for generating chemical stock solutions for conducting aquatic bioassays. Exposures have been conducted using several species offish, invertebrate, and mollusks in static and flow-through conditions using these methods. Stock solutions for 82 organic chemicals were prepared using these saturation units. The primary purpose of stock generation was to provide a continuous and consistent amount of toxicant laden solution at a measured analytical level which would be available to test organisms for the test duration. In the present study, the glass wool column and liquid/liquid saturators were used to provide consistent stock concentrations, at times approaching saturation, for fathead minnow (Pimephalespromelas)acute exposures. Attempts were made to achieve the maximum solubility of these compounds for comparison purposes to water solubility values available in the literature. Literature solubility values from a database by Yalkowsky et al. [1] provided information on temperatures and data quality which allowed comparison to values obtained from the present study. Twenty four compounds were identified and analyzed for the comparison of maximum obtainable solubility levels. Maximum saturator stock water concentrations were generally lower (R=0.98) but were in close agreement with published water solubility values. (c) 1999 Elsevier Science Ltd. All rights r e s e r v e d

1. INTRODUCTION

Since the implementation of the Toxic Substances Control Act (TSCA) in 1976, the U.S. Environmental Protection Agency CO.S. EPA) has been required to evaluate compounds for potential adverse effects to man and the environment. As part of this effort, the U.S. EPA, Mid-Continent Ecology 539

540 Division - Duluth (MED-D) has generated a systematic database [2] of 753 acute exposures of the fathead minnow,

(Pimephalespromelas),to 617 chemicals, mostly from the TSCA inventory of organic chemicals.

Because of the wide range of chemicat/physical properties of compounds in the MED-D database, it has been necessary to develop innovative methods for generating stock solutions for aqueous testing. For example, some compounds were extremely volatile while others were only minimally soluble in water or had a very low rate of dissolution. Also, some compounds were lethal only at or near their respective water solubilities, which necessitated methods of stock solution preparation which produced consistent concentrations near water solubility. The use of emulsified solutions or solvent carriers was deemed unacceptable, because the resulting solutions could be at concentrations above water solubility and/or the presence of solvent could affect bioavallabilityof the compounds. This study presents methods for preparing chemical saturation units that can be used to generate stable stock solutions, at maximum concentrations, for use in bioassays. Various classes of solid and liquid chemicals that pose handling problems were studied. For compounds with melting points (m.p.) < 25°C, liquid/liquid saturators were used with excess chemical and water stirred at a constant rate in a vessel closed to external air exchange. For solid chemicals (rap. >_25°C), glass wool column saturators were prepared by packing glass wool into a 'U' shaped glass tube. The compound was then coated onto the glass wool using a suitable solvent. Stock solutions were then generated by pumping water at a continuous rate through the column. Veith and Comstock [3] used a similar method, but with glass beads, sand, or XAD-7 resin as the inert medium. Glass wool was used in the present study because it provided a large surface area and allowed for increased flow rates through the column. The large surface area of the column improved efficiency and allowed for a single passage of water through the system to achieve chemical concentrations near saturation. Columns used by Veith and Comstock [3] required recirculation of the chemical solution from the column to a reservoir and back into the column in order to achieve concentrations near saturation. This paper reports water concentrations achieved by liquid/liquid and glass wool saturators for 82 organic chemicals. Comparisons of chemical concentrations produced by these saturators and published water solubility values from the Yalkowsk-y database [1] were also made for 24 chemicals.

2. MATERIALS AND METHODS

For both the liquid/liquid saturator and the glass wool columns the chemical solutions were prepared using sand filtered and aerated Lake Superior water. Although we use Lake Superior water, any source of natural water that is free of significant particulate matter would be appropriate. Hard reconstituted water as described in ASTM Guide E729 [4] is well suited for use in these systems where exposures with invertebrates are conducted under static conditions. The temperature of the incoming water

541 was maintained at 25 + 2°C, and the chemical characteristics of the water were similar to that reported by Biesinger and Christensen [5]. The saturation units were maintained at room temperature (-20°C).

Liquid/Liquid Saturation Units Saturation units were constructed using I-L reagent bottles, 3-L culture flasks, or 4- to 18-L glass carboys. Three phases: dead air space, aqueous test water and aqueous organic toxicant were present in the liquid/liquid saturator units (Fig. I). Vessel e~ciencies were similar, but to minimize the generation of waste material smaller vessels were used when less chemical was required (i.e. extremely toxic chemicals of low solubility). The main criterion followed in selecting vessels for the saturation units was the surface to volume ratio of the chemical/water interface. Increased surface to volume ratios greatly enhanced the ability to generate larger quantities of near saturated solutions, but this parameter is also dependent on individual chemical solubility, stir rate, retention time of solute and the flow rates of aqueous solutions through the saturation unit. Approximate internal surface areas achieved at the chemical/water interface ranged from 64.5 cm 2 for the 1-L reagent bottles to 612.9 cm 2 for the 18-L carboys and 3-L culture flasks. The mouth of each unit was tightly fit with a neoprene stopper (allowing no air exchange from the outside) to ensure an air-tight system (Fig. 1). Stoppers were taped in place to prevent loosening during use, thus preventing fluctuations in water level and ultimately changes in stock concentration. Two 7 6 cm long pieces of 0.64 cm o.d., 0.32 cm i.d. stainless steel (type 316) tubing were fit into two 0.64 cm stopper holes, which served as access ports for charging and venting the system. Access ports were sealed shut with clamps when not in use. Placed in each of two 0.32 cm stopper holes were lengths of 0.32 cm od., 0.16 cm i.d. stainless steel or Teflona tubing which served as inlet and outlet feeder lines (Fig. 1). Inlet, outlet and access tubing may require adjustments in length for variations in vessel size. These lines were at least three-fourths the height of the glass vessel used. The inlet line was attached to a diluent water line and supplied test water into the vessel at low pressure. A pump connected to a pulse dampener/pressure gauge on this inlet line is recommended to deliver diluent stock and monitor pressure in the saturation vessel. Once the stoppers were secured in place, hose clamps to the 0.64 cm tygon vent lines were closed, the saturation water outlet feeder line was opened and the pump started dispensing to waste. The airtight system was allowed to equilibrate a minimum of 2 h, but usually overnight to flush out possible soluble impurities.

Liquids with densi(y of
542 constant stir rate that pulled a vortex in the chemical layer of 1.5 cm or less was maintained. The lower end of the 0.32 cm inlet line was positioned either just above the water surface or 2 to 5 cm below the base of the vortex in the chemical layer. If the inlet line is above the surface, it is possible to monitor the rate of incoming water by recording the number of drops per minute added to the vessel. The outlet line was bent and the lower end placed in the lower half of the vessel (well below the layer of chemical) to ensure that pure chemical could not be pulled out of the unit.

Liquids with density > 1.0. Stir rate and surface area are important parameters for liquid compounds with a density greater than 1.0. Calculations were made to determine the amount of chemical necessary to do preliminary work and complete the exposure, and approximately twice the necessary amount of chemical was added to the vessel. Test water was added to the mid-point of the vessel providing a volume for diluent mixing (Fig. 1B). A magnetic stir bar was placed in the unit and the stopper assembly secured. The unit was placed on a stir plate with a stir rate slow enough to prevent beads of chemical from

Figure 1: Liquid/Liquid Saturation Unit

B. ChemicalDen~ty >1

A. Chemical Demdty<1

Figure 2: Glass Wool Column Satura~on Unit

inlet - - - ~

o~'~"~

oultet

m~

~amv~°eI1 s

I . L'L''';';":::- I

Pump

Pun

Olrnplr~rl

pru~JreGauge

being released from the chemical layer, but fast enough to provide rapid movement of chemical at the water interface. To prevent pure chemical from being pulled from the unit, the lower end of the outlet line was placed at the mid-point of the aqueous phase. The inlet line was positioned as close to the chemical and

543 water interface as possible without allowing incoming water to disrupt the organic phase. Disruption of the surface layer would cause the release of small chemical beads into the aqueous phase.

Liquids with densities approaching 1.0. Compounds with densities that approach 1.0 require special handling. Care must be taken to maintain the integrity of the chemical layer so as to ensure consistent saturation in the aqueous phase. Chemical beads breaking loose and entering the aqueous phase increase the potential of introduction of pure compound into the test unit or sampling components. To minimize this, vessel dimensions and water layer can be increased to help avoid chemical dispersion. Generally, an 18-L carboy (48.9 cm high by 26.0 cm diam.) with a water phase of 12- to 15-L was sufficient to avoid chemical dispersion. An approximate three-fold excess of chemical was used for generating test solutions. The inlet and outlet lines were placed well away from the chemical and water interface, and the stir rate was at the highest speed that did not allow beads of chemical to separate from the organic layer.

Glass Wool Column Saturation Units Columns were constructed using KimbleR 80400 medium walled glass tubing (25 mm o.d. with 0.24 cm walls). Tubing 1.2 m long, with finished (precisely cut) ends allowed for neoprene stoppers to be secured tightly. The tubes were washed using detergent and water and subsequently rinsed with water followed by acetone. Tubes were bent into 'U' shape keeping legs of the tube as close to the same length and as parallel as possible (Fig. 2). Pyrex~ 3950, glass wool (-50 g) was packed into each column leg using a rigid, unbreakable rod. The column was packed tightly from the start of each bend to within 8 cm of the end of each column leg, ensuring that a uniform amount of wool was used on each leg. This provided a total of-100 cm (-100 g) of glass wool to be coated with the chemical. Acetone was the primary solvent used for dissolving (methylene chloride and bexane were used occasionally) and coating chemicals on columns. The amount of chemical needed to conduct the bioassay(s) was calculated, based on a best estimate of solubility and toxicity of the chemical. A greater than 8 to 10-fold excess of cbemical (above the calculated amount) was then coated onto the column. For chemicals that had extremely low dissolution rates or when large volumes of toxicant solutions were needed, multiple columns were connected in parallel. Each glass wool column was coated with approximately 60-100 ml of chemical/solvent solution. A vacuum induced air flow facilitated solvent evaporation and chemical deposition by pulling the solution down each leg of the column. The best results for column coating were achieved when one leg was coated with half the chemical/solvent mixture (~40 ml) followed by evaporation of the solvent, and the process repeated on the second leg. Smaller multiple coatings on each leg of the column can be done but column plugging may result. If any of the chemical/solvent solution was pulled into the bottom of the 'U' shaped column during the evaporation phase, the vacuum was reversed and the column tipped so the solution could

544 be drawn back into the glass wool in the column leg being coated. When working with hexane or methylene chloride, rapid cooling was avoided by submersing the column in a water bath during the solvent evaporation process to prevent water condensation in the column. To ensure complete and even coating of the column, the chemical/solvent diluent should migrate down the entire glass wool core. After chemical coating was completed a small plug of glass wool was inserted into each end of the column. These plugs acted as filters to trap debris on the inlet line and any large particulate matter on the outlet line. Columns were usually capped with neoprene or silicone stoppers fit with 0.32 cm o.d. TeflonR tubing to serve as inlet and outlet lines and secured in place with fibrous strapping tape. The tubing penetrated the bottom 2 cm of each stopper leaving an air headspace within the column of about 2.5 cm which prevented contact between the stopper and toxicant solution. FMIR (Fluid Metering, Inc., Oyster Bay, NY) pumps were placed on the column inlet lines with an in-line pressure gauge and pulse dampener between the pump and column. The columns were flushed for a minimum of 4 h at a flow rate greater than anticipated during testing (5-25 ml/min) to remove more soluble impurities and dislodged particles of coated glass wool,

Analytical Techniques One of four techniques was used to analyze chemical residues in water samples from fish exposure tanks during each test: gas-liquid chromatography (GLC), high performance liquid chromatography (HPLC), UV-visible spectrophotometry and spectrofluorimetry. GLC analyses were performed by either direct aqueous injection or solvent extraction and subsequent analysis. All compounds analyzed by direct aqueous injection followed the method described by Knuth and Hoglund [6] using flame ionization, electron capture or nitrogen phosphorous detection procedures. Analytical standards for each chemical were prepared in hexane or methylene chloride. High performance liquid chromatography was accomplished using a C18 type column packing and a methanol-water, acetonitrile-water or acetonitrile-phosphate buffer mobile phase at various compositions. Standards were prepared in distilled water from methanol stock solutions. For UV spectrofluorometric determination standards were prepared using test water with known chemical components. All compound analyses included one fortified and one duplicate sample for every 6 to 12 water samples. Calibration curves for each compound were established by linear regression analysis for these five standards. For GLC and HPLC analysis, peak areas were used whenever possible and in a few instances, peak heights were used. Water concentrations (Table 1) reported for each chemical are mean values obtained from at least four analyzed samples taken over a 96-h period, and were corrected for spike recovery. Compound purity ranged from 88.8 to 99+%, Table 1.

545

Statistical Amdysis The octanol/water partition coefficients (log P) in Table 1 were either calculated using the CLOGP software (version 3.53) or measured values were obtained from the CLOGP STARLIST database [7]. Information on melting point was obtained from the manufacturer or from the ASTER system [8]. A regression analysis was conducted on the study data set and literature values strictly for comparison purposes.

3. RESULTS AND DISCUSSION

Comparison to Literature Values Compounds tested using stock solutions generated by either a glass wool column (n=47) or a liquid/liquid (n=35) saturator are presented in Table 1. For chemicals with duplicate values, the concentration associated with the lowest flow rate through the saturator was used. Four separate studies at flow rates of approximately 5 ml/min were available for carbaryl, and a geometric mean of these values was used in subsequent comparisons and analysis. The Yalkowsky database [1] was the source of published solubility values. This publication compiles literature values for organic chemicals, citing the original reference, the temperature at which the solubility determination was conducted, a conversion of the original units into g/L, and an evaluation code which ranks the quality of the method used to produce solubility. For the present analysis, when more than one value was available from the database for a specific compound, the value with a temperature closest to 20°C and the highest evaluation code was used. Published solubilities were available for 10 solid chemicals and 17 liquid chemicals (Table 1). Reagent bottles (l-L) with smaller surface areas than the other liquid/liquid saturators were used for pentachloroethane, 1,1,1-trichioroethane, and hexachloro-1,3butadiene. The saturator units used for these chemicals were useful in supplying consistent stock concentrations. However, the small surface area and high pump flow rates resulted in chemical concentrations that were much lower than reported solubility values [1]. Data from these three compounds were included in the statistical analysis given the comparable temperatures (25°C) with reported literature values. Solubilities reported in the literature for rotenone, ethyl salicylate and 1-bromobutane [1] were conducted at temperatures outside the present study's testing range of 20-25°C (100°C, 37°C, and 16°C, respectively). Differences in temperature create variance in solubility [9], and therefore these compounds were eliminated from the analysis. The correlation coefficient of the log molar concentrations for 24 literature values with data from the liquid/liquid and glass wool column saturators was 0.98. Piperine and diphenyl phthalate showed the greatest differences between solubility values reported in the literature and the concentration achieved with saturators used in the present study. Using the glass wool column, piperine measured a log unit less soluble and diphenyl phthalate was a log unit more soluble than published literature values. All saturator generated

546 chemical concentrations from the present study were lower than published values except for diphenyl phthalate and triphenyl phosphate. Volatile loss of solute during sampling may explain the low analyzed values for some of the liquid chemicals. Analyzed water concentrations for isopropylbenzene and 1-bromopropane were approximately 2.8 times and 5.7 times lower than their literature solubility values (Table 1), respectively. Direct introduction of the chemical stock into the water or solvent fraction within the collection vessel during sampling is recommended to reduce volatility and loss of the compound. With sampling tubes from the conventional serial diluter used in the isopropylbenzene and 1-bromopropane exposures, the chemical solutions dripped into or flowed down the side in the collection vessel before it entered the solvent layer and may have resulted in chemical loss through volatility. High flow rates could also be a factor in the reduced concentrations produced by several of these saturator units. The flow rates for isopropyibenzene, 1-bromopropane, and cyciohexane were >20 ml/min (Table 1). This flow rate was sufficient to provide stock solutions for bioassay needs but was not the most efficient rate for producing concentrations near solubility.

4. SUMMARY AND CONCLUSION

The liquid/liquid and glass wool column saturator are acceptable systems for producing stock solutions of consistent concentration for use in biological assays. Two specific conditions that can significantly alter the observed chemical concentration should be monitored. First, ifa chemical is depleted from either type of saturator, thereby decreasing the surface area in contact with the chemical, concentrations of stock solutions are reduced. Therefore, sufficient amounts of chemical must be used in these saturators to allow for continued use over the duration of the chemical exposure. Secondly, flow rates should be monitored daily. Fluctuations in flow rates can result in changes in the concentration of the resulting solution. For instance, data obtained from a 4-decylaniline glass wool saturator at flow rates of 5 and 15 ml/min resulted in chemical solutions of 0.251 and 0.152 rag/L, respectively. In this instance a three-fold decrease in the flow rate resulted in a greater than 1.5 increase in chemical concentration. Chemical volatilization at the time of sampling can be reduced by direct introduction of the chemical stock from the outlet tube into the water or solvent fraction within the collection vessel during sampling. Increased contact time of the solutions with the air prior to entry into the organic solvent layer can decrease the measured solute concentration for volatile compounds. Minimizing volatility loss during sampling and maximizing contact time at the chemical/water interface in liquid/liquid and glass wool column saturators increases the measured chemical concentrations. In general, the chemical concentrations achieved with the liquid/liquid and glass wool column saturators were lower but were in close agreement with published water solubility values (R=0.98). This report provides evidence that the liquid/liquid and glass wool saturators can produce chemical solutions that

Chemical

Manufacturer

Diphenyl phthalate

2,6-Dipheaylpyridine

2,5-Diphenylfilran

1,4-Diphenyl- 1,3-butadiene

1,4-Diiodobenzene

c~rbamate

2,4-Dibromo-5,6-dimethylphenyl-n-butyl

Dibenzofuran

4-Decylaailine

4-Chloro-m-tolyl-p-nitrophenol ether

p-Chlorophenyl-o-nitrophenyl ether

Carbaryl

m-(p-tert-Butylphenoxy)benzaldehyde

4-Bromophenyl-3-pyridyl ketone

4-Bromo-2',4',-dinitrodiphenyl ether

Anthraquinone

2 -Amino-4'-c,hlorobenzophenone

Adamantane

d

b

h

b

b

d

b

b

d

d

f

b

b

d

b

b

b

98

97+

Grade

Reagant

98

98

98

97

99

99

99

97

98

84-62-8

3558-69-8

955-83-9

886-65-7

624-38-4

8

132-64-9

37529-30-9

22532-72-5

1965-09-9

63-25-2

69770-23-6

14548-45-9

17589-66-1

84-65-1

2894-51-1

281-23-2

Number

(%)

99+

Registry

Purity

CAS

318.33

231.30

220.27

206.29

329.91

379.09

168.20

233.40

263.68

249.65

201.23

254.33

262.11

339.09

208.22

231.68

136.24

Weight

Molecular

4.53

4.82 c

5.51

5.04

4.39

5.75

4.12 c

6.30

5.72

4.79

2.36 °

5.93

2.97

4.79

3.39~

3.95

3.98

Log I~

71.0

74.0

91.0

151.0

131.0

83.0

25.0

142.0

126.0

285.0

103.0

205.0

(°C)

Point

e

•

•

•

e

Melting

0.725

0.560

0.120

0.0136

1.28

0.560

5.54

0.251

0.081

5.01

101

1.04

36.7

0.232

0.250

7.94

0.520

(rag/L)

Concentration

Observed

1.00

21.1

14.0

4.50

5.00

4.50

1.00

5.00

4.50

27.4

5.70

24.8

26.0

4.40

5.40

22.2

5.00

(ml/min)

Rate

Flow

concentrations are mean measured analytical values. Literature solubility measurements are from Yalkowsky et al. [1].

Chemical stock solutions generated using either a glass wool column or liquid/liquid saturator unit. All observed chemical

Solid Chemicals: Glass Wool Column Saturator

Table 1

0.082

1.40

10.02

103.9

1.35

Solubility (n~JL)

4~

97 99

98

Flavone

Hexachlorobenzene

Naphthalene

oxide

Tris-(p-(dimethylamino)phenyl)phosphine

Tris-(2,6-dichlorophenyl)-phosphate

807-20-5

75431-49-1

115-86-6

484-47-9

98

3808-87-5

Triphenyl phosphate

98

2,4,5 -Trichlorophenyl disulfide

103-19-5

98

98

p-Tolyl disulfide

595-90-4

13209-15-9

2,4,5-Triphenylimidazole

97

Tetraphenyl tin

83-79-4

593-08-8

97

a,a,a',a'-Tetrabromo-o-xylene

10453-86-8

603-34-9

97

Rotenone

98

88.8

Resmethrin

51630-58-1

94-62-2

882-33-7

2176-62-7

85-22-3

29082-74-4

91-20-3

407.54

539.92

326.29

296.37

245.33

198.35

425.01

246.39

427.11

421.77

394.42

338.45

419.90

285.34

218.34

251.33

500.67

379.68

128.17

290.49

596-85-0

222.24 284.80

Triphenylamine

93.5

Pydrin

199.34 261.46

118-74-1

525-82-6

104-42-7

1120-16-7

2-Tridecanone

99 97

Piperine

98

Pentachloropyfidinc

Phenyl disulfide

98

2,3,4,5 -Pentabromoethyibenzene

Octachlorostyrene 99+

97

4-Dodecylaniline

Manool

98

Dodecanamide

3.48

9.19

4.59 ~

6.25

5.74 c

5.02

8.72

5.74

n

5.17

4.10 °

6.18

6.20 c

2.70

4.41 c

4.34

6.52

7.94

3.30 °

6.60

5.31

3.48

7.38

4.06

49.0

275.0

125.0

29.0

140.0

43.0

224.0

114.0

165.0

45.5

23.0

130.0

58.0

124.0

137.0

81.0

230.0

97.0

40.0

110

0.330

0.006

3.44

0.013

0.0293

1.49

0.004

0.0917

0.0024

0.649

0.488

O.IIl

0.0158

13.60

0.397

1.57

0.0165

0.00638

33.4

0.460

0.0094

34.3

0.005

1.24

5.10

4.50

1.80

9.96

9.70

21.I

4.45

1.00

5.00

21.0

I.I0

2.30

1.00

1.00

5.50

28.3

4.80

1.00

3.50

4.50

I0.0

5.00

4.70

0.730

15.0~

100

34.4

0.0074

4~ oo

2.86 3.44 ° 4.90 3.64 1.99 3.60 ° 1.97 1.25~ 5.90

146.30 112.56 84.16 138.25 235.92 201.90 147.00 125.00 84.93 166.31

107-47-1 108-90-7 110-82-7 1647-16-1 583-53-9 I09-64-8 541-73-1 760-23-6 75-09-2 92-51-3

98 99+ 99+ 97 98 98 98 98 99+ 99

tert-Butyl sulfide

Chlorobenzene

Cyclohexane

1,9-Deeadiene

1,2-Dibromobenzene

1,3-Dibromopropane

1,3-Diehlorobenzene

3,4-Diehloro- 1-butene

Dieyelohexyl

Dichloromethane

3.32

178.36

110-06-5

97

ten-Butyl-disulfide

4.22

2.1&

123.00

99

1-Brornopropane

106-94-5

99

1-Bromooctane

3.80 ° 4.89"

165.08

4.36 °

179.11

193.13

2.75 °

2.13 c

137.03

78.11

111-25-1

99

1-Bromohexane

629-04-9

109-65-9

71-43-2

2.98

n

2.12

111-83-1

99

1-Bromoheptane

99.9+

99+ -

196.21

90-47-1

99+

q,r

193.25

1484-13-5

413.28

6.34

8.53

410.42 503.38

8.53

410.42

99

1-Bromobutane

Benzene

Liauid Chemicals: Liauid/Liauid Saturator

Xanthone

N-Vinyl carbazole

Tris-(m-nitrophenyl)phosphine oxide

g

g

3862-11-1

65695-97-8

98+

>90

Tris-(3,4-dimethylphenyl)-phosphate

Tris-(5-methyl-2-ni~ophenyl)phosphate

>90

Tris-(2,3 -dimethylphenyl)-phosphate

3.0

0.165

2.00

2.10

17000 -97.0

3.00

0.50

2.00

21.4

22.0

12.8

20.6

20.6

29.0

2.70

84.4

1300

78.4

0.430

37.9

266

45.8

1.97

433

10.2

22.3 11.9 1.18

21.0

35.5

3.50

5.00

1120

e

¢

5.10 30.5

5.99

180

1350

4.32

1.30

0.380

-61.0

-24.0

-34.0

4.00

6.5

-45.0

-4.00

-110.0

-55.0

-85.0

-58.0

-112.0

5.00

174.0

64.0

1.29

4.50

0.0047 2.48

4.60

0.013

20000

1700

52.0

502

2450

589'

1800

tJ I 4~

11.0

e

e

Measured log P obtained from Medchem STARLIST database [7].

k Shell Chemical Co. San Ramon, CA. 94583

J Dow Chemical Co. Midland, Mi. 48674

' Flow rate was not reported for this chemical.

h Eastman Kodak, Rochester, NY. 14650

Chemical Abstracts Services (CAS) registry number was not available for this chemical.

f Union Carbide Co. New York, NY. 10017

Melting point was not available for this chemical.

d Alfred Bader Library of Rare Chemicals, Milwaukee, WI. 53233

2700

1.73

70.0

16.3

151

63.7

14.3

0.40

20.5

6.00

20.9

0.47

5.90

7.00

32.5

3.67

1.00

21.3

5.60

21.0

17.5

27.7

13.9

29.5

1472

1175

573

500

586

65.3

3.20

12.4

4300

6700 u

v Liquid/liquid saturator was 1-L flask which decreased surface area (64.5 sO. cm).

Solubility determination conducted at 37 C [1].

t MCB Manufacaxring Chemists, Inc. Cincinnati, OH. 45212

s Solubility determination conducted at 16 C [1].

Burdich and Jackson Laboratories Inc. Muskegon,/vii. 49442

q J.T. Baker Chemical Co. PhiUipsburg, NJ. 08865

P Scientific Polymer Products. Ontario, NY. 14519

o Alfa Products, Danvers, MA. 01923

" A measured log P was not available, and one could not be calculated using CLOGP [7].

12.4

1034

349 v

289

4.00

314"

363

176

23.7

1.94"

11.8

10500

Fairfield Polymer Products, Newark, NJ. 07105

3.96

-87.0

-50.0

-93.0

-86.0

-29.0

-15.0

-21.0

-96.0

-19.0

-95.0

-35.0

2.0

12.0

-62.0

-76.0

m Solubility determination conducted at 100 C [1].

170.30

112-12-9

2.42 c

2.49 c

2.73 c

3.86

3.63

2.97 c

2.91

3.66 °

4.78 °

3.87

2.96

1.98 c

4.74

3.14

3.76

2.65

2.70

a Log P calculated using CLOGP software unless otherwise noted [7].

131.39

133.41

92.14

150.31

202.30

130.23

142.24

120.20

260.76

86.18

82.15

114.19

206.19

166.17

110.20

96.13

82.15

79-01-6

71-55-6

108-88-3

629-19-6

76-01-7

111-87-5

821-55-6

98-82-8

87-68-3

110-54-3

592-46-1

110-43-0

330-93-8

118-61-6

764-13-6

625-86-5

513-81-5

b Aldrich Chemical Company, Milwaukee, WI. 53233

95

2-Undecanone

98

99.8+

99+ -

98

96

99

99+

99

98

99+

99

98

97

97 - 99

99

99

98

98

b

b

r

b

b

b

b

b

b

b

b

b

d

b

b

b

b

Trichloroethylene

1,1,1 -Trichloroethane

Toluene

Propyi disulfide

Pentaehloroethane

1-Oetanol

2-Nonanone

Isopropylbenzene

Hexaehloro- 1,3-butadiene

Hexane

2,4-Hexadiene

2-Heptanone

p-Fluorophenyt ether

Ethylsalieylate

2,5-Dimethyl-2,4-hexadiene

2,5-Dimethylfuran

2,3-Dimethyl- 1,3 -butadiene

551 approach water solubility if the surface to volume ratio and contact time betwe¢~ the water and the chemical are sufficient. ACKNOWLEDGEMENTS

The authors wish to thank Greg Elonen, Marilynn Hoglund and Alex Hoffman for assistance in research associated with this study. We are grateful to Gary Holcombe, Lawrence Burkhard, Allan Batterman and Nancy Novy for their technical review of this manuscript, and to Roger LePage for graphics. The authors also thank Gilman Veith, Steven Broderius and Gerald Anldey for their assistance, support and constructive discussions.

REFERENCES

1.

Yalkowsky, S.H., S.C. Valvani, W. Kuu, and IL Dannenfelser. (Eds). 1987. Arizona Database of Aqueous Solubility. 2nd edition. University of Arizona, Tucson AZ

2.

Russom, C.L., S.P. Bradbury, S.J. Broderious, D.E. Hammermeister, and 1LA. Drummond. 1997. Predicting modes of toxic action from chemical structure: Acute toxicity in the fathead minnow (Pimephalespromelas). Env. Tox. Chem. 16(5): 948-967.

3.

Veith, G.D. and V.M. Comstoek. 1975. Apparatus for continuously saturating water with hydrophobie organic chemicals. 32(10): 1849-1851

4.

ASTM. 1993 Standard guide for conducting acute toxicity tests with fish, macroinvertebrates and amphibians. American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA. Annual Book of Standards. Vol. 11.04. pp. 456-475.

5

Biesinger, K.E. and G.M. Christensen. 1972. Effects of various metals on survival, growth, reproduction and metabolism of Daphnia magna J. Fish. Res. Board Can. 29:16911700.

6

Knuth, M.L., and M.D. Hoglund. 1984 Quantitative analysis of 68 polar compounds from ten chemical classes by direct aqueous injection gas chromatography. J. Chromatog. 285:153-160.

7.

Leo, AI and D. Weininger. 1988. CLOGP software and STARLIST database, version 3.53 for VAX/VMS Pomona Medicinal Chemistry Project, Pomona College, Claremont, CA 91711 Russom, C.L., E.B. Anderson, B.E. Greenwood and A. Pilli. 1991. ASTER: An integration of the AQUIRE database and the QSAR system for use in ecological risk assessment. So: Total Environ. 109/110:667-670.

9.

Yalkowsky, S.H. and S.C. Valvani. 1979 Solubilities and partitioning. 2. Relationship between aqueous solubilities, partition coefficients, and molecular surface areas of rigid aromatic hydrocarbons. J. Chem. Eng. Data 24(2): 127-129