N-butyl phenyl ether

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Tests were conducted following the EPA (U.S. EPA, 1989)., sufficient details provided in report which meet basic scientific principles, however, no specific details on dose levels were provided.

Principles of method if other than guideline:

U.S. Environmental Protection Agency. 1989 Short term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms, 2nd ed EPA 600/4-89-001 and supplement EPA 600/4 89 OOlA Cincinnati, OH

GLP compliance:

not specified

Analytical monitoring:

yes

Details on test solutions:

Dilution water was filtered, aerated, and heated Lake Superior water.

For butylphenylether, two 1-L saturators were used simultaneously. Liquid saturators were prepared a few days before the test started in order to check that their concentration remained constant; they were continuously stirred. After evaporation of the solvent, dilution water was pumped over the column to produce a saturated solution.

Five concentrations (with a dilution factor of 0.65) plus a control group were tested. No other details provided.

Test organisms (species):

Pimephales promelas

Details on test organisms:

Fathead minnow (Pimephales promelas) larvae less than 24 h old were used. The fish were obtained from the U.S. Environmental Protection Agency
(EPA) in Newtown, Ohio. Fish were fed live <24-h-old brine shrimp nauplii (Artemia salina) three times a day, except on day 7, when they were fed only once.

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

7 d

Remarks on exposure duration:

96-hr toxicity data was also collected in this study design.

Post exposure observation period:

No data.

Hardness:

hardness = 45.5 +/- 1 mg/L as CaCO

Test temperature:

temperature = 25 +/- 1 degree C

pH:

pH = 7.65 +/- 0.6

Dissolved oxygen:

dissolved oxygen (DO) = 7.3 +/- 1 mg/L

Salinity:

Not applicable.

Nominal and measured concentrations:

No specific details provided on concentration levels.

Details on test conditions:

Exposure apparatus:
Tests were conducted under flow-through conditions with the minidiluter system described by Benoit et al. The test material was tested with a flow rate of 63 ml/min. Stock solutions were delivered to the system with FMI pumps (Fluid Metering, Inc., Oyster Bay, NY). The diluter distributed five concentrations plus the control, with a dilution factor of 0.65. Six tanks, one for each concentration, were partitioned to obtain two replicate exposure chambers (5.2 x 18 x 5.4 cm each, with a capacity of 500 ml). Under low and high flowrate conditions, the solutions in each chamber were entirely renewed 14.4 and 36 times per day, respectively.

Test method:
The method of the 7-d test was based on the procedure described by Norberg and Mount and followed the protocol of EPA methods. The test lasts 7 d, and the end points are survival and growth (dry weight of the larvae at the end of the test). The test was run at 25 +/- 1°C with a 16:8-h light:dark photoperiod. Forty larvae were exposed to each concentiation (20 larvae per chamber in 500 ml of solution). In each exposure tank, mortality, water temperature, DO, and pH were measured daily and conductivity was measured at least three times per test. Hardness and alkalinity were measured two or three times a week in the control and in the highest test concentration. Fish were fed live <24-h-old brine shrimp nauplii (Artemia salina) three times a day, except on day 7, when they were fed only once. At the termination of the test, the surviving fish in each duplicate chamber were pooled, dried at 100°C for about 15 h, and weighed. The toxicant concentration in the stock solution and in each exposure tank was analyzed before starting the tests and two or three times during the test.

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 5.88 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: (Larval (<24hrs old))

Duration:

7 d

Dose descriptor:

LC50

Effect conc.:

3.28 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: CL: 2.97-3.63 (Larvae)

Duration:

7 d

Dose descriptor:

NOEC

Effect conc.:

< 0.91 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: Growth

Remarks on result:

other: (Larvae)

Duration:

7 d

Dose descriptor:

LOEC

Effect conc.:

<= 0.91 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: Growth

Remarks on result:

other: (Larvae)

Duration:

7 d

Dose descriptor:

other: Subchronic value (geometric mean between NOEC and LOEC)

Effect conc.:

< 0.91 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: Growth

Remarks on result:

other: (Larvae)

Duration:

7 d

Dose descriptor:

LOEC

Effect conc.:

3.6 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: (Larvae)

Duration:

7 d

Dose descriptor:

NOEC

Effect conc.:

2.43 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: (Larvae)

Duration:

7 d

Dose descriptor:

other: Subchronic value (geometric mean between NOEC and LOEC)

Effect conc.:

2.96 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: (Larvae)

Duration:

7 d

Dose descriptor:

IC50

Effect conc.:

2.16 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: Growth

Remarks on result:

other: CL: 2.06-2.27 (Larvae)

Duration:

7 d

Dose descriptor:

IC50

Effect conc.:

1.97 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: Biomass

Remarks on result:

other: CL: 1.8-2.25 (Larvae)

Reported statistics and error estimates:

Statistical methods:
All the calculations were made with measured toxicant concentrations. The trimmed Spearman-Karber technique was used to calculate the median lethal concentrations (LC50s) at 96 h and day 7. The probit analysis, using the EPA Probit Analysis Program-Version 1.4, was applied to generate concentration-effect curves. NOEC and LOEC for survival and growth were determined by means of hypothesis test statistics, using the Minitab data analysis software (copyright Minitab, Inc., State College, PA), which includes a weighted analysis of variance, followed by a one-tailed Dunnett’s test. The subchronic value (SChV) was calculated as the geometric mean of the NOEC and LOEC. Results were also analyzed by means of a point estimation technique, using the monotone smoothing and linear interpolation procedure. Its underlying basic assumptions are that the test results are monotonic (the observed response means decrease, or do not increase, as the toxicant concentration increases) and the responses are a linear function of the concentration (in a piecewise manner, i.e., from one tested concentration to the next one). This method permits the calculation of the ICp values, that is, the concentrations resulting in a given percentage ( p ) inhibition of the relevant response, along with their confidence limits. Both the IC25 and IC50 were estimated for two distinct end points: growth and biomass, the latter being a combination of survival and growth. Growth is calculated as the weight of each replicate divided by the surviving number of fish; biomass is calculated by taking the weight of each replicate and dividing by the original number of fish.

Validity criteria fulfilled:

yes

Conclusions:

The lethal and sublethal effects of six monosubstituted derivatives of benzene (MBs) were measured by using the 7-d test with fathead minnow larvae. The LC50s for larvae were compared to those derived from the acute test. Butylphenylether was one of the substances tested. The larvae were more sensitive than juvenile fish. The following results have been reported for Butylphenyether:
96 h LC50 5.77 mg/L mortality CL: 5.2-6.41 (Juveniles (28-33 days old))
96 h LC50 > 5.88 mg/L mortality (Larval (<24hrs old))
7 d LC50 3.28 mg/L mortality CL: 2.97-3.63 (Larvae)
7 d NOEC < 0.91 mg/L other: Growth (Larvae)
7 d LOEC <= 0.91 mg/L other: Growth (Larvae)
7 d other: MATC < 0.91 mg/L other: Growth (Larvae)
7 d LOEC 3.6 mg/L mortality (Larvae)
7 d NOEC 2.43 mg/L mortality (Larvae)
7 d other: MATC 2.96 mg/L mortality (Larvae)
7 d IC50 2.16 mg/L other: Growth CL: 2.06-2.27 (Larvae)
7 d IC50 1.97 mg/L other: Biomass CL: 1.8-2.25 (Larvae)

Executive summary:

The lethal and sublethal effects of six monosubstituted derivatives of benzene (MBs) were measured by using the 7-d test with fathead minnow larvae. The LC50s for larvae were compared to those derived from the acute test. Butylphenylether was one of the substances tested. The following results have been reported for Butylphenyether:

96 h LC50 5.77 mg/L mortality CL: 5.2-6.41 (Juveniles (28-33 days old))

96 h LC50 > 5.88 mg/L mortality (Larval (<24hrs old))

7 d LC50 3.28 mg/L mortality CL: 2.97-3.63 (Larvae)

7 d NOEC < 0.91 mg/L other: Growth (Larvae)

7 d LOEC <= 0.91 mg/L other: Growth (Larvae)

7 d other: MATC < 0.91 mg/L other: Growth (Larvae)

7 d LOEC 3.6 mg/L mortality (Larvae)

7 d NOEC 2.43 mg/L mortality (Larvae)

7 d other: MATC 2.96 mg/L mortality (Larvae)

7 d IC50 2.16 mg/L other: Growth CL: 2.06-2.27 (Larvae)

7 d IC50 1.97 mg/L other: Biomass CL: 1.8-2.25 (Larvae)

Description of key information

Butyl phenyl ether acute toxicity to fish was determined in a single fish species, the fathead minnow (Pimephales promelas).

Two fathead minnow 96-hr LC50 values for Butyl Phenyl Ether are available; one 96-hr LC50 was determined with juvenile fish, while the other 96-hr LC50 value was determined with larval fathead minnows. Additionally, a 7-day LC50 value with larval fathead minnows is available for Butyl Phenyl Ether. Since the 7-day LC50 value was the lowest for Butyl Phenyl Ether, this value of 3.28 mg/L was used as the key value in the chemical safety assessment for fish acute toxicity.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

3.28 mg/L

Additional information

Butyl phenyl ether acute toxicity to fish was determined in a single fish species, the fathead minnow (Pimephales promelas). Two fathead minnow 96-hr LC50 values for butyl phenyl ether are available; one 96-hr LC50 was determined with juvenile fish (i.e. 5.77 mg/L), while the other 96-hr LC50 value was determined with larval fathead minnows (i.e. >5.88 mg/L). Additionally, a 7-day LC50 value with larval fathead minnows is available for butyl phenyl ether. Since the 7-day LC50 value was the lowest for butyl phenyl ether, this value of 3.28 mg/L was used as the key value in the chemical safety assessment for fish acute toxicity.