4,4'-isopropylidenediphenol

Sediment toxicity

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

sediment toxicity: long-term

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: Sediment Water Chironomid Toxicity Test Using Spiked Sediment. Guideline #218. Adopted 13 April 2004, Paris, France.

Deviations:

not specified

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

All BPA concentrations reported in the present study were adjusted for purity of the test substance and were reported on a sediment dry weight basis (mg/kg-dw).

Vehicle:

yes

Details on sediment and application:

Preparation of overlying water
Because BPA is a rapidly biodegraded substance, overlying water dosed with BPA was added to test vessels containing BPA-amended sediment to help maintain sediment BPA concentrations, under the assumption that some BPA in dosed overlying water would partition to sediment.
Concentrated dosing solutions were prepared by mixing finely ground BPA with deionized water, sonicating for 30 min, then adjusting the pH to 12 by the addition of 12 M NaOH. Because the amounts of stock solution that ultimately entered test vessels were small, pH was not affected in the test systems. The amounts of dosing solution added to dilution water at each renewal were selected to achieve the calculated overlying water concentration if the concentrations of BPA in the water (Cwater) and sediment (Csediment) were at equilibrium in the test vessel. The concentration of BPA in the dosed overlying water to be used in each treatment was calculated using the substance’s octanol-water partition coefficient (Kow) and organic carbon content (OC) of the sediment according to the following calculation [Seth R, Mackay D, Muncke J. 1999. Estimation of organic carbon partition coefficients and its variability for hydrophobic chemicals. Environ Sci Technol 33: 2390-2394.]:
Cwater = Csediment / ([Kow x 0.35] x OC
The Kow for BPA is 2500 [Staples CA, Dorn PB, Klečka GM, O’Block ST, Harris LR. 1998. A review of the environmental fate, effects and exposures of bisphenol A. Chemosphere 36: 2149-2173] and the OC contents were 2.1, 2.3, and 7.2 % for the three sediments. Nominal concentrations were determined for each species.

Test organisms (species):

Chironomus riparius

Details on test organisms:

The oligochaetes and midges used during this study were obtained from the cultures maintained in the laboratory. The population of amphipods used in this study was obtained from Chesapeake Cultures, Inc., a commercial supplier located in Hayes, VA, USA.

Study type:

laboratory study

Test type:

semi-static

Water media type:

freshwater

Type of sediment:

artificial sediment

Duration:

28 d

Exposure phase:

total exposure duration

Hardness:

Soft water was characterized as having a total hardness range and total alkalinity as calcium carbonate (CaCO3) of 64 to 76 and 22 mg/L

Test temperature:

20 ± 2 °C,

pH:

Soft water was characterized as having a pH range of 6.4 to 7.2

Nominal and measured concentrations:

Concentration of Bisphenol-A: 29, 54, 110, 210, and 490 mg/kg-dw (measured)

Details on test conditions:

Toxicity testing with midges (C. riparius)
Prior to test initiation, egg masses were removed from culture aquaria, placed in plastic cups, and observed until hatch. Hatched larvae were reared in laboratory well water and fed ground flaked fish food (10 mg/mL) until testing began. Two to three-day old midge larvae were used to initiate testing.

The test was performed with five sediment concentrations (50, 100, 200, 400 and 800 mg/kg-dw) that were selected based on preliminary testing, plus solvent and negative controls. Other than BPA concentrations and the use of 20 midge larvae per vessel, test vessels for both treatments and controls were established identically to test vessels set up for L. variegatus.

Nominal concentrations for dosed overlying water in the 50, 100, 200, 400 and 800 mg/kg-dw sediment treatments were 2.7, 5.4, 11, 22 and 44 mg/L, respectively. Overlying water (300 of the 600-mL volume) was replaced three times weekly. Test vessels were incubated in a water bath at 20 ± 2 °C, aerated continuously, and illuminated with a light:dark cycle of 16:8 h at a constant light intensity of 540 to 810 lux during the light hours. Prior to introducing midge larvae to the test vessels and on days 1 to 10, 1.0-mL aliquots of ground flaked fish food were added daily to each test vessel.
On days 11 to termination, 2.0-mL aliquots were added daily to each test vessel.

Observations of midge emergence (typically starting at day 10 and lasting until day 28) were made at test initiation and daily until test termination on day 28. The number and sex of adult midges that emerged daily were recorded, with male midges identified by their plumose antennae. Development rates for male-only, female-only, and male and female midges combined, were determined in each test vessel. Mean development time represents the mean time span between the addition of test organisms (day 0) and the emergence of the adult midges. Development rate is the reciprocal of the
development time and represents the portion of larval development that takes place per day. Development rate is the preferred endpoint because its variance is lower and, being more homogeneous and closer to being normally distributed as compared to development time, parametric test procedures may be used. For the calculation of development rate, the number of midges observed on inspection day X are assumed to be emerged at the mean of the time interval between day X and day X-1 (inspection interval = 1 day). The mean development rate per vessel is calculated according to the
following calculation:
Mean Development Rate = Sumi(i=1 to m) [Fix Xi] / Ne

where, i = index of inspection intervals 1 to m; m = number of inspection intervals; Fi= number of emerged midge during each inspection interval i; Xiis the development rate of the midges emerged in the interval i and Ne= total number of midge emerged during the study. Xiwas calculated as follows:

Xi= 1 / [dayi– (Li/2)]

where, dayi= inspection day (days since test initiation) and Li= length of inspection interval (i = 1 d).

Reference substance (positive control):

no

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

140 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

emergence rate

Remarks on result:

other: (120 to 150) mg/kg-dw

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

>= 210 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

development rate

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

110 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

emergence rate

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

54 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

emergence rate

BPA Concentrations in sediment, overlying water and pore water

Mean measured concentrations of BPA in dosed sediment, overlying water and pore water are shown in Table. Across all tests, the concentrations of BPA in the artificial and natural sediments averaged 56.2 ± 3.49 % to 77.6 ± 1.83 % of nominal. Overlying water concentrations in all test systems decreased to concentrations at or near the detection limits during the test (varying detection limits of <0.47 to 11 μg/L). Pore water concentrations also decreased during the test but not to the same extent as the overlying water.

Mean measured concentrations of BPA in sediment, overlying water, and pore water

Organism	Sediment (mg/kg-dw)		Mean measured as % Nominal^a	Overlying water (mg/L)	Pore Water (mg/L)	Sediment- Pore water Distribution Coefficient (Kd)	OC- normalized Distribution Coefficient (Koc)^b
	Nominal	Mean measured
Midge	50	29	58	0.58	3.2	9.1	394
	100	54	54	1.15	6.5	8.3	361
	200	110	55	2.43	14.5	7.6	330
	400	210	53	4.75	36.3	5.8	252
	800	490	61	14.0	70.3	7.0	303
			Avg. 56.2 (3.49)				Avg. 330 (55)

^aValues in parentheses are standard deviations

^bOrganic carbon (OC) contents were 2.1, 2.3, and 7.2 % for the tests with the oligochaete, midge, and marine amphipod, respectively

Validity criteria fulfilled:

yes

Conclusions:

On day 28 exposure, for C. riparius, the LOEC was 110 mg/kg-dw and the NOEC was 54 mg/kg-dw based on percent emergence.
For percent emergence and development rate, 28-d EC50 values (with 95 % confidence intervals) were 140 (120 to 150) mg/kg-dw and >210 mg/kg-dw (95 % confidence intervals could not be calculated since no effects on development rate were observed).

Executive summary:

Effects of BPA on benthic organisms were assessed in the present study using spiked sediments as well as overlying water containing BPA. The premise of this method is that the test system will enable the exposure of the test organisms to BPA from dosed sediment, spiked overlying water, and pore water as BPA equilibrates between sediment solids and the pore water. Within the test systems, overlying water concentrations decreased rapidly to below detection limits during all tests despite renewal of the water three times per week. This was expected due to the rapid biodegradability of BPA in surface waters and sediments. Pore water concentrations of BPA also decreased somewhat during the course of the 28 day tests, but never below detection limits. The ratio of a sediment concentration and its pore water concentration is a distribution coefficient (Kd value) and ranged from 5.8 to 9.1 for the midge test.

In accordance with the OECD Guideline for Testing of Chemicals. Sediment Water Chironomid Toxicity Test Using Spiked Sediment. Guideline #218 (Adopted 13 April 2004, Paris, France) five measured concentrations (29, 54, 110, 210, and 490 mg/kgdw) of BPA for all treatments were exposed for 28 days.

For C. riparius, the LOEC was 110 mg/kg-dw and the NOEC was 54 mg/kg-dw based on percent emergence. For percent emergence and development rate, 28-d EC50 values (with 95 % confidence intervals) were 140 (120 to 150) mg/kg-dw and >210 mg/kg-dw (95 % confidence intervals could not be calculated since no effects on development rate were observed).

Reference 2

Endpoint:

sediment toxicity: long-term

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: Sediment-Associated Contaminants with the Amphipod Leptocheirus plumulosus. EPA/600/R-01/020, Washington, DC, USA.

Deviations:

not specified

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

All BPA concentrations reported in the present study were adjusted for purity of the test substance and were reported on a sediment dry weight basis (mg/kg-dw).

Vehicle:

yes

Details on sediment and application:

Preparation of overlying water
Because BPA is a rapidly biodegraded substance, overlying water dosed with BPA was added to test vessels containing BPAamended sediment to help maintain sediment BPA concentrations, under the assumption that some BPA in dosed overlying water would partition to sediment.
Concentrated dosing solutions were prepared by mixing finely ground BPA with deionized water, sonicating for 30 min, then adjusting the pH to 12 by the addition of 12 M NaOH. Because the amounts of stock solution that ultimately entered test vessels were small, pH was not affected in the test systems. The amounts of dosing solution added to dilution water at each renewal were selected to achieve the calculated overlying water concentration if the concentrations of BPA in the water (Cwater) and sediment (Csediment) were at equilibrium in the test vessel. The concentration of BPA in the dosed overlying water to be used in each treatment was calculated using the substance’s octanol-water partition coefficient (Kow) and organic carbon content (OC) of the sediment according to the following calculation [Seth R, Mackay D, Muncke J. 1999. Estimation of organic carbon partition coefficients and its variability for hydrophobic chemicals. Environ Sci Technol 33: 2390-2394.]:
Cwater = Csediment / ([Kow x 0.35] x OC
The Kow for BPA is 2500 [Staples CA, Dorn PB, Klečka GM, O’Block ST, Harris LR. 1998. A review of the environmental fate, effects and exposures of bisphenol A. Chemosphere 36: 2149-2173] and the OC contents were 2.1, 2.3, and 7.2 % for the three sediments. Nominal concentrations were determined for each species.

Preparation of sediment
Dosing of the sediment according to Ditsworth et al. [Ditsworth GR, Schults DW, Jones JKP, 1990. Preparation of benthic substrates for sediment toxicity testing. Environ Toxicol Chem 9: 1523-1529.] is presented in detail in Supplemental Information. In brief, dosing was accomplished by coating dry sand with BPA dissolved in acetone, drying the sand, and adding the sand to artificial sediment or natural marine sediment, followed by periodic rolling of the sediment in storage vessels (within a refrigerator at 2 to 8 °C) over the course of seven days to facilitate incorporation of the BPA into the sediment. Dosed sediment was placed into test vessels along with overlying water containing BPA, which was partially (~50 to 60 %) renewed three times per week during the 28 day tests.

Test organisms (species):

Leptocheirus plumulosus

Details on test organisms:

The oligochaetes and midges used during this study were obtained from the cultures maintained in the laboratory. The population of amphipods used in this study was obtained from Chesapeake Cultures, Inc., a commercial supplier located in Hayes, VA, USA.

Toxicity testing with estuarine amphipods (L. plumulosus)
Amphipods were acclimated to test conditions prior to testing using the same seawater (adjusted to 20 ppt) and natural marine sediment used for testing. All L. plumulosus neonates used for testing were approximately the same age and size as indicated by being able to pass through a 0.6-mm sieve, but retained on a 0.25-mm sieve.

Study type:

laboratory study

Test type:

semi-static

Water media type:

saltwater

Type of sediment:

artificial sediment

Limit test:

no

Duration:

28 d

Exposure phase:

total exposure duration

Test temperature:

25 ± 1 °C

pH:

Natural seawater: pH range of 7.6 to 8.5 was collected from Cape Cod Canal, Bourne, MA from about 4 m offshore at a depth of approximately 0.5 m.
Prior to use in the study with L. plumulosus, seawater was adjusted with laboratory well water to a pH range of 6.9 to 8.7.

Salinity:

Natural seawater: salinity range of 30 to 33 parts per thousand (ppt) was collected from Cape Cod Canal, Bourne, MA from about 4 m offshore at a depth of approximately 0.5 m. Prior to use in the study with L. plumulosus, seawater was adjusted with laboratory well water to a salinity range of 20 to 22 ppt.

Nominal and measured concentrations:

Nominal concentrations for dosed overlying water in the 2.6, 6.4, 16, 40 and 100 mg/kgdw sediment treatments were 0.41, 0.10, 0.25, 0.63, and 1.6 mg/L, respectively.

Details on test conditions:

Test vessels were prepared by adding a layer of marine sediment approximately 2 cm thick (about 175 mL of wet sediment) to test vessels followed by addition of 725 mL of clean overlying seawater for controls and sediment treatment-specific dosing water for BPA treatments. The test was performed with five sediment concentrations (2.6, 6.4, 16, 40 and 100 mg/kg-dw) that were selected based on preliminary testing, plus solvent and negative controls. Test vessels for both treatments and controls were established in the same way that test vessels were set up for the freshwater organisms, except for the use of marine sediment, differing BPA concentrations, and the use of five replicates instead of four in the treatment groups. At test initiation, 20 neonates were added to all test vessels, including those prepared for chemical analysis.

Nominal concentrations for dosed overlying water in the 2.6, 6.4, 16, 40 and 100 mg/kgdw sediment treatments were 0.41, 0.10, 0.25, 0.63, and 1.6 mg/L, respectively. Overlying water (400 of the 600-mL volume) was replaced three times weekly. Test vessels were incubated in a water bath at 25 ± 1 °C and illuminated with a light:dark cycle of 16:8 h at a constant light intensity of 620 to 750 lux during the light hours. Prior to introducing neonates to test vessels and on days 1 to 19, 2.0-mL aliquots of flaked fish food were added to each vessel three times per week. After day 19, 4.0-mL aliquots were added to each test vessel.

Observations of mortality were made at test initiation and daily until test termination on day 28. On day 28, the total number of surviving amphipods was determined in each test vessel by sieving sediment through a 0.60 mm sieve to recover all surviving adult amphipods. Young amphipods were recovered by further sieving through a 0.25 mm sieve. Recovered amphipods were transferred to glass sample jars for counting. Reproduction was determined as the number of young per surviving adult amphipod in each replicate test vessel. Growth was determined at test termination by pooling
surviving adult amphipods from each replicate test vessel and drying at 61 to 62 °C for approximately 24 h in an oven. Pooled dry amphipods were weighed on an analytical balance to the nearest 0.01 mg.

Reference substance (positive control):

no

Duration:

28 h

Dose descriptor:

LC50

Effect conc.:

49 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: (46 to 51) mg/kg-dw

Duration:

28 h

Dose descriptor:

LC50

Effect conc.:

54 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: (14 to 76) mg/kg-dw

Duration:

28 h

Dose descriptor:

LC50

Effect conc.:

38 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: (11 to 52) mg/kg-dw

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

32 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

other: dry weight

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

78 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

12 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

other: dry weight

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

32 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

reproduction

BPA Concentrations in sediment, overlying water and pore water

Mean measured concentrations of BPA in dosed sediment, overlying water and pore water are shown in Table. Across all tests, the concentrations of BPA in the artificial and natural sediments averaged 56.2 ± 3.49 % to 77.6 ± 1.83 % of nominal. Overlying water concentrations in all test systems decreased to concentrations at or near the detection limits during the test (varying detection limits of

< 0.47 to 11 μg/L). Pore water concentrations also decreased during the test but not to the same extent as the overlying water.

Mean measured concentrations of BPA in sediment, overlying water, and pore water

Organism	Sediment (mg/kg-dw)		Mean measured as % Nominal^a	Overlying water (mg/L)	Pore Water (mg/L)	Sediment- Pore water Distribution Coefficient (Kd)	OC- normalized Distribution Coefficient (Koc)^b
	Nominal	Mean measured
Marine	2.6	2.0	79	0.015	0.04	50	694
Amphipod	6.4	5.0	78	0.054	0.10	50	694
	16	12	75	0.10	0.26	46	641
	40	32	81	0.40	0.77	42	577
	100	78	78	0.73	1.95	40	566
			Avg. 77.6 (1.83)				Avg. 630 (65)

^aValues in parentheses are standard deviations

^bOrganic carbon (OC) contents were 2.1, 2.3, and 7.2 % for the tests with the oligochaete, midge, and marine amphipod, respectively.

Validity criteria fulfilled:

yes

Conclusions:

On day 28 exposure, for the marine amphipod L. plumulosus, the LOEC based on survival and reproduction was 78 mg/kg-dw and the NOEC was 32 mg/kg-dw. For dry weight, the LOEC was 32 mg/kg-dw and the NOEC was 12 mg/kg-dw. For survival, growth, and reproduction, 28-d LC50 values (with 95 % confidence intervals) were 49 (46 to 51) mg/kg-dw, 54 (14 to 76) mg/kg-dw, and 38 (11 to 52) mg/kg-dw, respectively.

Executive summary:

Effects of BPA on benthic organisms were assessed in the present study using spiked sediments as well as overlying water containing BPA. The premise of this method is that the test system will enable the exposure of the test organisms to BPA from dosed sediment, spiked overlying water, and pore water as BPA equilibrates between sediment solids and the pore water. Within the test systems, overlying water concentrations decreased rapidly to below detection limits during all tests despite renewal of the water three times per week. This was expected due to the rapid biodegradability of BPA in surface waters and sediments. Pore water concentrations of BPA also decreased somewhat during the course of the 28 day tests, but never below detection limits. The ratio of a sediment concentration and its pore water concentration is a distribution coefficient (Kd value) and ranged from 40 to 50 for the marine amphipod test.

In accordance with the Methods for Assessing the Chronic Toxicity of Marine and Estuarine Sediment-Associated Contaminants with the Amphipod Leptocheirus plumulosus (EPA/600/R-01/020, Washington, DC, USA). five measured concentrations (2.0, 5.0, 12, 32, and 78 mg/kg-dw) of BPA for all treatments were exposed for 28 days.

For the marine amphipod L. plumulosus, the LOEC based on survival and reproduction was 78 mg/kg-dw and the NOEC was 32 mg/kg-dw. For dry weight, the LOEC was 32 mg/kg-dw and the NOEC was 12 mg/kg-dw. For survival, growth, and reproduction, 28-d LC50 values (with 95 % confidence intervals) were 49 (46 to 51) mg/kg-dw, 54 (14 to 76) mg/kg-dw, and 38 (11 to 52) mg/kg-dw, respectively.

Reference 3

Endpoint:

sediment toxicity: long-term

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: Sediment-Water Lumbriculus Toxicity Test Using Spiked Sediment. Guideline # 225. Adopted 16 October 2007, Paris, France.

Deviations:

not specified

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

yes

Details on sediment and application:

Preparation of overlying water
Because BPA is a rapidly biodegraded substance, overlying water dosed with BPA was added to test vessels containing BPAamended sediment to help maintain sediment BPA concentrations, under the assumption that some BPA in dosed overlying water would partition to sediment.
Concentrated dosing solutions were prepared by mixing finely ground BPA with deionized water, sonicating for 30 min, then adjusting the pH to 12 by the addition of 12 M NaOH. Because the amounts of stock solution that ultimately entered test vessels were small, pH was not affected in the test systems. The amounts of dosing solution added to dilution water at each renewal wereselected to achieve the calculated overlying water concentration if the concentrations of BPA in the water (Cwater) and sediment (Csediment) were at equilibrium in the test vessel. The concentration of BPA in the dosed overlying water to be used in each treatment was calculated using the substance’s octanol-water partition coefficient (Kow) and organic carbon content (OC) of the sediment according to the following calculation [Seth R, Mackay D, Muncke J. 1999. Estimation of organic carbon partition coefficients and its variability for hydrophobic chemicals. Environ Sci Technol 33: 2390-2394.]:
Cwater = Csediment / ([Kow x 0.35] x OC
The Kow for BPA is 2500 [Staples CA, Dorn PB, Klečka GM, O’Block ST, Harris LR. 1998. A review of the environmental fate, effects and exposures of bisphenol A. Chemosphere 36: 2149-2173] and the OC contents were 2.1, 2.3, and 7.2 % for the three sediments. Nominal concentrations were determined for each species.

Preparation of sediment
Dosing of the sediment according to Ditsworth et al. [Ditsworth GR, Schults DW, Jones JKP, 1990. Preparation of benthic substrates for sediment toxicity testing. Environ Toxicol Chem 9: 1523-1529.] is presented in detail in Supplemental Information. In brief, dosing was accomplished by coating dry sand with BPA dissolved in acetone, drying the sand, and adding the sand to artificial sediment or natural marine sediment, followed by periodic rolling of the sediment in storage vessels (within a refrigerator at 2 to 8 °C) over the course of seven days to facilitate incorporation of the BPA into the sediment. Dosed sediment was placed into test vessels along with overlying water containing BPA, which was partially (~50 to 60 %) renewed three times per week during the 28 day tests.

Test organisms (species):

Lumbriculus variegatus

Details on test organisms:

The oligochaetes and midges used during this study were obtained from the cultures maintained in the laboratory. The population of amphipods used in this study was obtained from Chesapeake Cultures, Inc., a commercial supplier located in Hayes, VA, USA.

Study type:

laboratory study

Test type:

semi-static

Water media type:

freshwater

Type of sediment:

artificial sediment

Limit test:

no

Duration:

28 d

Exposure phase:

total exposure duration

Hardness:

total alkalinity ranges as CaCO3 of 180 to 190 and 84 to 94 mg/L

Test temperature:

20 ± 2 °C

pH:

total alkalinity ranges as CaCO3 of 180 to 190 and 84 to 94 mg/L

Nominal and measured concentrations:

Concentrations of Bisphenol-A: 2.0, 5.1, 13, 32, and 80 mg/kg-dw (nominal)
Concentrations of Bisphenol-A: 1.6, 3.9, 11, 22, and 57 mg/kg-dw (measured)

Details on test conditions:

Toxicity testing with oligochaetes (L. variegatus)
Fourteen days prior to test initiation, worms from the culture were removed and artificially fragmented to synchronize the population, using a scalpel to remove the anterior ends. Synchronized oligochaetes were acclimated to test sediment (i.e., water
and artificial sediment without amendment with food or test material) for a period of thirteen days to regenerate new heads. The synchronization of worms is performed to avoid “uncontrolled” regeneration and reproduction that may contribute to high variation in the test results. Twice during the acclimation period, synchronized oligochaetes were fed 6.4 mL of a finely ground suspension (100 mg/mL) of flaked fish food. The test was performed with five different BPA concentrations (2.0, 5.1, 13, 32, and 80 mg/kg-dw) that were selected based on preliminary testing, plus solvent (acetone) and negative controls. Four replicate 1000-mL clear glass beakers used as test vessels were prepared for each treatment and six replicate vessels were prepared for both the solvent and negative controls. Four additional replicate vessels were prepared for each treatment and control to determine BPA concentrations in overlying water, pore water, and sediment. The test vessels prepared for chemical analysis were maintained similarly to the other replicates and included 10 organisms per vessel.Test vessels were prepared by adding a 150 mL aliquot of wet sediment to the vessels followed by
addition of 600 mL of clean overlying water for controls and sediment treatment-specific dosing water for the BPA treatments. Nominal concentrations for the dosed overlying water in the 2.0, 5.1, 13, 32, and 80 mg/kg-dw sediment treatments were approximately 0.1, 0.25, 0.65, 1.6, and 4 mg/L, respectively. Three times weekly, test solutions were renewed by removing 300 mL water and replacing with fresh solutions. At test initiation, oligochaetes were added impartially until each test vessel contained 10 organisms. Test vessels were positioned randomly in a water bath at 20 ± 2 °C, aerated
continuously, and illuminated with a light:dark cycle of 16:8 h at a constant light intensity of 350 to 490 lux during the light hours. During exposure, oligochaetes fed on urtica powder and alpha-cellulose powder that had been added to all sediment (BPA treatments and both controls) during its preparation. The combined feed represented 0.25 % of the total sediment by weight.

Test vessels were examined daily and observations of mortality and abnormal behavior (e.g., leaving the sediment) were made. On test day 28 of exposure, the number of surviving oligochaetes recovered and the biomass of surviving oligochaetes were determined in all test vessels. If fewer than ten oligochaetes were observed and no dead oligochaetes were recovered, the missing individuals were assumed to have died. Biomass was determined by placing the entire number of surviving oligochaetes from each replicate vessel in a tared weighing tin and drying in an oven at 100 ± 5 °C overnight (18 to 24 hours). Following drying, tins were cooled to room temperature in desiccators and weighed to the nearest 0.01 mg on a calibrated analytical balance.

Reference substance (positive control):

no

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

> 57 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

other: biomass

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

57 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

other: biomass

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

22 mg/kg sediment dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

other: biomass

BPA Concentrations in sediment, overlying water and pore water

Mean measured concentrations of BPA in dosed sediment, overlying water and pore water are shown in Table. Across all tests, the concentrations of BPA in the artificial and natural sediments averaged 56.2 ± 3.49 % to 77.6 ± 1.83 % of nominal. Overlying water concentrations in all test systems decreased to concentrations at or near the detection limits during the test (varying detection limits of <0.47 to 11 μg/L). Pore water concentrations also decreased during the test but not to the same extent as the overlying water.

Mean measured concentrations of BPA in sediment, overlying water, and pore water

Organism	Sediment (mg/kg-dw)		Mean measured as % Nominal^a	Overlying water (mg/L)	Pore Water (mg/L)	Sediment- Pore water Distribution Coefficient (Kd)	OC- normalized Distribution Coefficient (Koc)^b
	Nominal	Mean measured
Oligochaete	2.0	1.6	80	0.02	0.10	16	762
	5.1	3.9	77	0.05	0.33	11.8	563
	13	11	85	0.27	1.06	10.4	494
	32	22	70	0.40	2.85	7.7	368
	80	57	71	1.36	8.80	6.5	308
			Avg. 76.2 (6.43)				Avg. 500 (180)

^aValues in parentheses are standard deviations

^bOrganic carbon (OC) contents were 2.1, 2.3, and 7.2 % for the tests with the oligochaete, midge, and marine amphipod, respectively.

Validity criteria fulfilled:

yes

Conclusions:

On day 28 exposure, for L. variegatus, the LOEC was 57 mg/kg-dw and the NOEC was 22 mg/kg-dw based on numbers of oligochaetes recovered per replicate and biomass per replicate. Since no concentration tested resulted in ≥50 % reduction in numbers of oligochaetes recovered or biomass per replicate, EC50 values were empirically estimated to be >57 mg/kg-dw, the highest mean measured concentration tested.

Executive summary:

Effects of BPA on benthic organisms were assessed in the present study using spiked sediments as well as overlying water containing BPA. The premise of this method is that the test system will enable the exposure of the test organisms to BPA from dosed sediment, spiked overlying water, and pore water as BPA equilibrates between sediment solids and the pore water. Within the test systems, overlying water concentrations decreased rapidly to below detection limits during all tests despite renewal of the water three times per week. This was expected due to the rapid biodegradability of BPA in surface waters and sediments. Pore water concentrations of BPA also decreased somewhat during the course of the 28 day tests, but never below detection limits. The ratio of a sediment concentration and its pore water concentration is a distribution coefficient (Kd value) and ranged from 7.7 to 16 for the oligochaete test.

In accordance with the OECD Guidelines for Testing of Chemicals. Sediment-Water Lumbriculus Toxicity Test Using Spiked Sediment. Guideline # 225 (Adopted 16 October 2007, Paris, France) five measured concentrations ( 1.6, 3.9, 11, 22, and 57 mg/kg-dw) of BPA for all treatments were exposed for 28 days.

For L. variegatus, the LOEC was 57 mg/kg-dw and the NOEC was 22 mg/kg-dw based on numbers of oligochaetes recovered per replicate and biomass per replicate. Since no concentration tested resulted in ≥50 % reduction in numbers of oligochaetes recovered or biomass per replicate, EC50 values were empirically estimated to be >57 mg/kg-dw, the highest mean measured concentration tested.

Description of key information

On day 28 exposure, for the marine amphipod L. plumulosus, the LOEC based on survival and reproduction was 78 mg/kg-dw and the NOEC was 32 mg/kg-dw. For dry weight, the LOEC was 32 mg/kg-dw and the NOEC was 12 mg/kg-dw. For survival, growth, and reproduction, 28 -d LC50 values (with 95 % confidence intervals) were 49 (46 to 51) mg/kg-dw, 54 (14 to 76) mg/kg-dw, and 38 (11 to 52) mg/kg-dw, respectively.

Key value for chemical safety assessment

EC50 or LC50 for freshwater sediment:

11 mg/kg sediment dw

EC10, LC10 or NOEC for freshwater sediment:

12 mg/kg sediment dw

Additional information

Staples et al., 2015_Leptocheirus plumulosus

Effects of Bisphenol A on benthic organisms were assessed in the present study using spiked sediments as well as overlying water containing Bisphenol A. The premise of this method is that the test system will enable the exposure of the test organisms to Bisphenol A from dosed sediment, spiked overlying water, and pore water as Bisphenol A equilibrates between sediment solids and the pore water. Within the test systems, overlying water concentrations decreased rapidly to below detection limits during all tests despite renewal of the water three times per week. This was expected due to the rapid biodegradability of Bisphenol A in surface waters and sediments. Pore water concentrations of Bisphenol A also decreased somewhat during the course of the 28 day tests, but never below detection limits. The ratio of a sediment concentration and its pore water concentration is a distribution coefficient (Kd value) and ranged from 40 to 50 for the marine amphipod test.

In accordance with the Methods for Assessing the Chronic Toxicity of Marine and Estuarine Sediment-Associated Contaminants with the Amphipod Leptocheirus plumulosus (EPA/600/R-01/020, Washington, DC, USA). five measured concentrations (2.0, 5.0, 12, 32, and 78 mg/kg-dw) of Bisphenol A for all treatments were exposed for 28 days.

For the marine amphipod L. plumulosus, the LOEC based on survival and reproduction was 78 mg/kg-dw and the NOEC was 32 mg/kg-dw. For dry weight, the LOEC was 32 mg/kg-dw and the NOEC was 12 mg/kg-dw. For survival, growth, and reproduction, 28-d LC50 values (with 95 % confidence intervals) were 49 (46 to 51) mg/kg-dw, 54 (14 to 76) mg/kg-dw, and 38 (11 to 52) mg/kg-dw, respectively.

Staples et al., 2015_Lumbriculus variegatus

Effects of Bisphenol A on benthic organisms were assessed in the present study using spiked sediments as well as overlying water containing Bisphneol A. The premise of this method is that the test system will enable the exposure of the test organisms to Bisphenol A from dosed sediment, spiked overlying water, and pore water as Bisphenol A equilibrates between sediment solids and the pore water. Within the test systems, overlying water concentrations decreased rapidly to below detection limits during all tests despite renewal of the water three times per week. This was expected due to the rapid biodegradability of Bisphenol A in surface waters and sediments. Pore water concentrations of Bisphenol A also decreased somewhat during the course of the 28 day tests, but never below detection limits. The ratio of a sediment concentration and its pore water concentration is a distribution coefficient (Kd value) and ranged from 7.7 to 16 for the oligochaete test.

In accordance with the OECD Guidelines for Testing of Chemicals. Sediment-Water Lumbriculus Toxicity Test Using Spiked Sediment. Guideline # 225 (Adopted 16 October 2007, Paris, France) five measured concentrations ( 1.6, 3.9, 11, 22, and 57 mg/kg-dw) of Bisphenol A for all treatments were exposed for 28 days.

For L. variegatus, the LOEC was 57 mg/kg-dw and the NOEC was 22 mg/kg-dw based on numbers of oligochaetes recovered per replicate and biomass per replicate. Since no concentration tested resulted in ≥50 % reduction in numbers of oligochaetes recovered or biomass per replicate, EC50 values were empirically estimated to be >57 mg/kg-dw, the highest mean measured concentration tested.

Staples et al., 2015_Chironomus riparius

Effects of Bisphenol A on benthic organisms were assessed in the present study using spiked sediments as well as overlying water containing Bisphenol A. The premise of this method is that the test system will enable the exposure of the test organisms to Bisphenol A from dosed sediment, spiked overlying water, and pore water as Bisphenol A equilibrates between sediment solids and the pore water. Within the test systems, overlying water concentrations decreased rapidly to below detection limits during all tests despite renewal of the water three times per week. This was expected due to the rapid biodegradability of Bisphenol A in surface waters and sediments. Pore water concentrations of Bisphenol A also decreased somewhat during the course of the 28 day tests, but never below detection limits. The ratio of a sediment concentration and its pore water concentration is a distribution coefficient (Kd value) and ranged from 5.8 to 9.1 for the midge test.

In accordance with the OECD Guideline for Testing of Chemicals. Sediment Water Chironomid Toxicity Test Using Spiked Sediment. Guideline #218 (Adopted 13 April 2004, Paris, France) five measured concentrations (29, 54, 110, 210, and 490 mg/kgdw) of Bisphenol A for all treatments were exposed for 28 days.

For C. riparius, the LOEC was 110 mg/kg-dw and the NOEC was 54 mg/kg-dw based on percent emergence. For percent emergence and development rate, 28-d EC50 values (with 95 % confidence intervals) were 140 (120 to 150) mg/kg-dw and >210 mg/kg-dw (95 % confidence intervals could not be calculated since no effects on development rate were observed).