Chlorothalonil

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21 Jul 1979 to 8 Sep 1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

Bluegill sunfish is exposed to 14C-labelled test substance for 30-d bioaccumulation phase and followed by a 14-d depuration phase at 22 ± 1 °C. BCF is calculated based on the concentraton of the substance in the test solution and organism in steady-state.

GLP compliance:

yes

Radiolabelling:

yes

Details on sampling:

SAMPLING
- Fish sampling schedule: At 1, 3, 7, 10, 14, 22 and 30 days of the bioaccunulation phase and at 1, 3, 7, 10 and 14 days of the depuration phase.
- Water sampling schedule: At 0, 1, 3, 7, 10, 14, 22 and 30 days of the bioaccunulation phase and 0, 1, 3, 7, 10 and 14 days of the depuration phase.
- Fish sampling method: On days 1, 3 and 10 of the bioaccumulation phase and 1, 7 and 10 of the depuration phase, three fish were removed from each of the test aquaria. The muscle tissue (fillet), defined as the edible portion including the bones, from each of these fish was combined. The viscera, including the head, guts and fins, from each of these fish were combined. Also included In the visceral section were the brain and all internal organs of the digestive, respiratory, circulatory, endocrine, reproductive and excretory systems. Each combined tissue sample was homogenized with dry ice in a mill. After sublimation of the dry ice duplicate subsamples of the homogenized fillet and visceral tissue were analyzed indirectly for radioactivity by total combustion analysis.
- Water sampling method: On each sampling day, a minimum 250 mL portion of water was removed from each aquarium using an 8 oz. polyethylene bottle. Water samples from the duplicate test aquaria were combined for each sampling day. Water samples from the duplicate control aquaria were combined for each sampling day. Duplicate 5 mL portions of each combined sample were transferred to separate liquid scintillation counting vials. A 15 mL portion of Aquasol-2was added to each vial, the vials were sealed, and the contents were mixed by manually shaking.

Vehicle:

yes

Remarks:

ethanol

Details on preparation of test solutions, spiked fish food or sediment:

PREPARATION OF TEST MATERIAL
A 0.3173 g of the test substance was weighed and quantitatively transferred to a 250 mL round bottom flask using toluene. A total of 100 mL toluene was added to the flask and the tests substance was dissolved by mixing. A 4.78 milliCurie portion of uniformly ring labeled 14C-test substance with a specific activity of 31.4 milliCuries per millimole was added to the flask. The solution was mixed by magnetic stirring for 30 minutes, The solution was evaporated to dryness under reduced pressure. The resulting specific activity was calculated to be 29369 dpm/µg.

INTRODUCTION OF TEST MATERIAL
A concentrated working standard solution of the test material was prepared by dissolving 357.5 mg of the 14C-labelled test substance in 235 ml of ethanol to result in a concentration of 1.52 mg/mL. The test solution was prepared by diluting the concentrated working standard solution with ethanol to result in a concentration of 14C-labelled test substance of 11.97 mg/L. The test solution was transferred to the Mariott bottle of the test system and shielded from light by covering the Mariott bottle with aluninim foil, The test solution was prepared fresh at least every eight days.

Test organisms (species):

Lepomis macrochirus

Details on test organisms:

TEST ORGANISM
- Common name: Bluegill sunfish
- Length at study initiation: 65 mm to 76 mm with a mean length of 69 mm
- Weight at study initiation: 4.4 g to 5.5 g with a mean weight of 4.9 g

ACCLIMATION
The test animals were held in culture tanks and observed for general health and suitability for a minimun of 14 days prior to testing. During
observation and acclimation , the test animals were held in culture tanks supplied with flowing well water.
- Well water temperature: 14°C to 21 °C
- Health during acclimation (any mortality observed): During the observation period , less than 10% mortality of the test animals was observed , thus indicating their suitability for testing. Based upon available documentation and behavior observations, the test animals were judged to be in excellent condition. During a 72 hour period, the test animals were gradually acclimated to the 22 °C test temperature.

FEEDING (holding, observation acclimation and test periods)
- Food type: Standard conmercial fish food
- Frequency: Daily

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

30 d

Total depuration duration:

14 d

Test temperature:

22 ± 1 °C

pH:

Bioaccumulation: 8.0 - 8.6
Depuration: 7.9 - 8.2

Dissolved oxygen:

Bioaccumulation: 3.8 - 8.2 mg O2/L
Depuration: 5.2 - 7.2 mg O2/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 liter glass aguaria
- Fill volume: 70 liters of aerated well water
- Type of flow-through: Proportional diluter
- Flow rate: 500 mL per minute per aquarium
- No. of organisms per vessel: 120
- No. of vessels per concentration: 2
- No. of vessels per contro: 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Well water
- Dissolved oxygen: 9.3 mg O2/L
- Alkalinity: 380 mg/L as CaCO3
- pH: 7.7
- Hardness: 260 mg/L as CaCO3
- Water quality measurement: The water quality parameters of temperature, dissolved oxygen, pH and ammonia were measured throughout the study.

RANGE-FINDING
- Study desigh: 96- hour acute toxicity test of the substance to bluegill sunfish was performed.
- Results used to determine the conditions for the definitive study: Results of this study Indicated that the no mortality or abnormal behavior of the test animals was observed at concentration of 0.084 mg/L. Based upon this data, it was judged that the test concentration selected for the residue accunulation, distribution and depuration study should not exceed one-tenth of 0.084 mg/L. To minimize mortality of the test animals during the study, the nominal test concentration was selected to be 0.008 mg/L 14C-labelled test substsnace.

Nominal and measured concentrations:

- Nominal concentration: 0.0080 mg/L
- Mean measured concentration: 0.0072 mg/L, see Table1 and Table 2 in 'Any other information on materials and methods incl. tables'

Reference substance (positive control):

no

Key result

Conc. / dose:

0.007 mg/L

Temp.:

22 °C

pH:

8

Type:

BCF

Value:

264 dimensionless

Basis:

whole body w.w.

Time of plateau:

30 d

Calculation basis:

steady state

Conc. / dose:

0.007 mg/L

Temp.:

22 °C

pH:

8

Type:

BCF

Value:

76 dimensionless

Basis:

edible fraction

Remarks:

fillet

Time of plateau:

30 d

Calculation basis:

steady state

Conc. / dose:

0.007 mg/L

Temp.:

22 °C

pH:

8

Type:

BCF

Value:

514 dimensionless

Basis:

non-edible fraction

Remarks:

visceral tissue

Time of plateau:

30 d

Calculation basis:

steady state

Elimination:

yes

Parameter:

other: 80% of the accumulated 14C-residues were eliminated from the whole fish

Depuration time (DT):

14 d

Elimination:

yes

Parameter:

other: 46% of the accumulated 14C-residues were eliminated from the fillet

Depuration time (DT):

14 d

Elimination:

yes

Parameter:

other: 85% of the accumulated 14C-residues were eliminated from the visceral tissue

Depuration time (DT):

14 d

Details on results:

An overview of the result is provided in Table 3 and Table 4 in 'Any other information on results incl. tables'.
After 30 days of exposure, the mean 14C-residues were 1.9 ppm in whole fish, 0.55 ppm in the fillet and 3.7 ppm in the viscera. The visceral tissue contained approximately 7 times the 14C- residues detected in the edible fillet tissue. The bioaccunulation factors were 264X, 76X and 514X for whole fish, fillet and visceral tissues , respectively. At the end of the 14 day depuration, 80%, 46% and 35% of the accumulated 14C-residues were eliminated from the whole fish, fillet and visceral tissues, respectively.

Table 3. Concentration (ppm) of 14C-residues as the test substance equivalents in blue gill sunfish during bioaccumulation.

Day	Whole fish		Fillet		Viscera
	Assay values	Mean value	Assay values	Mean value	Assay values	Man value
1	1.8	1.8	0.14	0.14	3.7	3.8
	1.8		0.14		3.9
3	1.4	1.8	0.20	0.20	1.9	1.9
	2.1		0.19		1.8
7	2.6	2.7	0.72	0.72	4.2	4.3
	2.7		0.72		4.3
10	2.5	2.5	0.50	0.51	5.1	5.4
	2.5		0.51		5.6
14	2.9	3.0	0.66	0.70	5.8	5.8
	3.1		0.73		5.8
22	2.4	2.4	0.53	0.53	4.2	4.3
	2.4		0.52		4.4
30	1.9	1.9	0.54	0.55	3.7	3.7
	1.8		0.55		3.6

 

Table 4. Concentration (ppm) of 14C-residues as the test substance equivalents in blue gill sunfish during depuration.

Day	Whole fish		Fillet		Viscera
	Assay values	Mean value	Assay values	Mean value	Assay values	Man value
1	1.3	1.4	0.45	0.48	2.3	2.2
	1.5		0.51		2.0
3	0.79	0.81	0.34	0.35	1.2	1.2
	0.83		0.35		1.2
7	0.58	0.57	0.24	0.26	0.74	0.77
	0.56		0.27		0.79
10	0.49	0.48	0.25	0.26	0.75	0.75
	0.47		0.26		0.74
14	0.37	0.38	0.26	0.30	0.53	0.54
	0.39		0.34		0.54

 

Validity criteria fulfilled:

not specified

Conclusions:

Based on the findings, the corresponding bioconcentration factors were 264, 76, and 514 times the mean exposure concentration of 0.0072 mg/L14C-labelled test substance equivalents for the whole fish, fillet and visceral tissues, respectively. After 14 days of depuration 80.0% of the accumulated 14C-residues was eliminated from whole fish tissue, 45.5% was eliminated from the fillet and 85.4% was eliminated from the visceral tissue.

Executive summary:

A study was conducted to evaluate the potential for accumulation, distribution and depuration of the 14C-labelled test substance residues in bluegill sunfish (Lepomis macrochirus) exposed to a nominal 14-C labelled test substance concentration of 0.0080 mg/L (the mean measured concentration was 0.0072 mg/L). The study was conducted without following a standard guideline but it was performed following an inhouse SOP and in compliance with GLP criteria. Four 100 litre glass aquaria (two for control and two for treatment) were used in this study with a flow through system. The temperature of the water in the aquaria was controlled by immersing the aquaria In a circulating water bath maintained at 22 ± 1 °C by the use of submersible heating elements. The bioaccumulation phase of the study was 30 days and the depuration phase of the study was 14 days. After 30 days exposure to 14C-labelled test substance in a flow through aquatic system, bluegill sunfish accumulated 1.9, 0.55 and 3.7 ppm 14C-labelled test substance equivalents in the whole fish, fillet and visceral tissues, respectively. The corresponding bioaccumulation factors were 264, 76, and 514 times the mean exposure concentration of 0.0072 mg/L 14C-labelled test substance equivalents for the whole fish, fillet and visceral tissues, respectively. After 14 days of depuration 80.0% of the accumulated, 14C-residues was eliminated from whole fish tissue, 45.5% was eliminated from the fillet and 85.4% was eliminated from the visceral tissue.

Description of key information

BCF = 264 in whole fish (bluegill sunfish), no guideline followed, Szalkowski 1980

Key value for chemical safety assessment

BCF (aquatic species):

264 dimensionless

Additional information

A study was conducted to evaluate the potential for accumulation, distribution and depuration of the 14C-labelled test substance residues in bluegill sunfish (Lenomis macrochirus) exposed to a nominal 14-C labelled test substance concentration of 0.0080 mg/L (the mean measured concentration was 0.0072 mg/L). The study was conducted without following a standard guideline but it was performed following an inhouse SOP and in compliance with GLP criteria. Four 100 litre glass aquaria (two for control and two for treatment) were used in this study with a flow through system. The temperature of the water in the aquaria was controlled by immersing the aquaria In a circulating water bath maintained at 22 ± 1 °C by the use of submersible heating elements. The bioaccumulation phase of the study was 30 days and the depuration phase of the study was 14 days. After 30 days exposure to 14C-labelled test substance in a flow through aquatic system, bluegill sunfish accumulated 1.9, 0.55 and 3.7 ppm 14C-labelled test substance equivalents in the whole fish, fillet and visceral tissues, respectively. The corresponding bioaccumulation factors were 264, 76, and 514 times the mean exposure concentration of 0.0072 mg/L 14C-labelled test substance equivalents for the whole fish, fillet and visceral tissues, respectively. After 14 days of depuration 80.0% of the accumulated, 14C-residues was eliminated from whole fish tissue, 45.5% was eliminated from the fillet and 85.4% was eliminated from the visceral tissue.