N-methoxy-1-(2,4,6-trichlorophenyl)propan-2-amine

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Endpoint:

bioaccumulation in aquatic species: fish

Remarks:

The bioconcentration test was conducted solely to comply with non-EU national registration requirements.

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 July 2015 to 30 October 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 305 (Bioaccumulation in Fish: Aqueous and Dietary Exposure) -I: Aqueous Exposure Bioconcentration Fish Test

Version / remarks:

October 2012

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

no

Details on sampling:

The Analytical Procedure, SMV (E) 3200945-01V, used to confirm the concentration of the substance in samples of test media and the fish tissues during the test. Concentrations of the subsatnce in the test media samples and fish tissue samples were determined by Liquid Chromatography with Mass Spectrophotometry (LC-MS/MS).

Samples (10 mL) of the control and 0.010 mg/L test concentration were taken for analysis on Days -7, -4, 0, 1, 3, 6, 9 and 13 of the uptake phase and on Days 1, 4 and 7 of the depuration phase. At each sampling occasion, duplicate samples were taken. One for chemical analysis and one as a ‘back up’ sample should further analysis be required. To determine the concentration of the substance in fish, four fish from the test vessel were taken on Days 1, 3, 6, 9 and 13 of the uptake phase. Additionally, four fish were taken from the test vessel on Days 1, 4 and 7 of the depuration phase. Fish were also removed from the control vessel at the same time.
On each sampling occasion, the fish (selected at random) were removed from each tank, rinsed quickly with water using a wash bottle and gently blotted dry. They were then concussed (by striking the cranium) and killed by severing the spinal cord above the opercular region followed by destruction of the brain. Each fish was then wet weighed and the total length measured.

Vehicle:

yes

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

An initial stock solution was prepared by dissolving ca 20 mg of subtsnace in 1000 mL of treated mains water with the aid of stirring for ca 30 minutes and sonication for ca 10 minutes. An aliquot (500 mL) of the 20 mg/L stock solution was diluted in a final volume of 5 litres of treated mains water to give a 2.0 mg/L stock solution.
The 2.0 mg/L stock solution was dosed at a rate of 1.5 ± 10% mL/minute to a diluent flow rate of 300 ± 10% mL/minute to give a nominal 0.010 mg/L test concentration. A control was prepared using treated mains water only dosed at a rate of 300 ± 10% mL/minute. The flow rate represented an approximate medium exchange rate of five volumes per 24 hours.
The duration of the uptake and depuration phases was 13 and 7 days, respectively. The final sample timing for the uptake phase was on Day 13 of the exposure period however the fish remained in the exposure media up to Day 15 of the test until all results were available. At the end of the uptake phase, the remaining fish were exposed to untreated dilution water only. Throughout the depuration phase, the diluent pumps were delivering dilution water at a nominal 300 ± 10% mL/min per test vessel.
Prior to the addition of fish to the test vessels, and during the uptake phase, the flow rates of the stock solution and dilution water into the test vessel were checked daily. The flow rates of the dilution water into each test vessel were checked daily during the depuration phase.
The test preparations were observed to be colourless solutions throughout the duration of the test.

Test organisms (species):

Lepomis macrochirus

Details on test organisms:

Species: Bluegill Sunfish (Lepomis macrochirus).
Source: Osage Catfisheries Inc., USA
Acclimatisation period: 14 days
Treatment for disease: None reported
Weight and length of fish at test start: Mean weight: 0.89 g
Mean length: 4.0 cm
Feeding: Commercially prepared fish food 1 – 2 % of total biomass daily

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

13 d

Total depuration duration:

7 d

Hardness:

67 to 68 mg/L as CaCO3

Test temperature:

23.2 to 24.3 oC

pH:

7.10 to 7.62

Dissolved oxygen:

96 to 104 %

Nominal and measured concentrations:

The test was conducted at a nominal concentration of 0.010 mg/L
Chemical analysis of the test media during the uptake phase showed measured concentrations to range from 0.00235 to 0.00430 mg/L representing 24% to 43% of nominal value.

Reference substance (positive control):

not specified

Lipid content:

7.433 %

Time point:

end of exposure

Conc. / dose:

0.01 mg/L

Temp.:

>= 23.2 - <= 24.3 °C

pH:

7.1

Type:

BCF

Value:

178 dimensionless

Basis:

whole body w.w.

Calculation basis:

steady state

Conc. / dose:

0.01 mg/L

Temp.:

>= 23.2 - <= 24.3 °C

pH:

7

Type:

BCF

Value:

177 dimensionless

Basis:

whole body w.w.

Calculation basis:

kinetic, corrected for growth

Elimination:

yes

Parameter:

other:

Remarks:

79% reduction in body burden

Depuration time (DT):

1 d

Elimination:

yes

Parameter:

other:

Remarks:

99% reduction in body burden

Depuration time (DT):

4 d

Rate constant:

overall uptake rate constant (L kg-1 d-1)

Value:

191.524

Rate constant:

overall depuration rate constant (d-1)

Value:

1.097

Rate constant:

growth rate constant (d-1)

Value:

0.015

Rate constant:

growth-corrected depuration rate constant (d-1)

Value:

1.082

Validity criteria fulfilled:

yes

Conclusions:

The substance was shown to have limited bioconcentration potential in fish over a 13 day exposure period, with all BCF values determined <200. The substance was rapidly eliminated from the fish with approximately 79% reduction in body burden after 1 day depuration, 99% reduction after 4 days and 100% reduction following a 7 day depuration period.
Although relatively consistent, some of the measured concentrations of the substance in the test media were outside the ±20% of the mean measured concentration (±34%). These minor deviations were not considered large enough to impact on the outcome of the study, and were considered to be due to the low concentration employed in the test and difficulties seen when dosing through the test rig. All other validity criteria were satisfied and as a result, the test is considered valid.

Executive summary:

The study was conducted in accordance with the requirements of OECD Chemicals Testing Guideline No.305 Bioaccumulation in Fish: Aqueous and Dietary Exposure (adopted 2 October 2012) Section I: Aqueous Exposure Bioconcentration Fish Test.

The study was conducted using a flow-through test design with continuous renewal of test media during the test. The test was conducted using bluegill sunfish (Lepomis macrochirus).

The test was conducted at a nominal concentration of 0.010 mg/L. A single replicate test vessel was prepared for the test concentration and control group.

During the exposure (uptake) phase, Lepomis macrochirus were continuously exposed to CA5204A for a period of 15 days under continuous flow conditions. The final sample timing for the uptake phase was on Day 13 of the exposure period however the fish remained in the exposure media until all results were available. A control treatment, consisting of a test vessel treated only with dilution water, was also included. Thereafter, the remaining fish were exposed to dilution water only for the post-exposure (depuration) phase of the test. Flow-through conditions were also employed for the depuration phase of the test which lasted 7 days.

Chemical analysis of the test media during the uptake phase showed measured concentrations to range from 0.00235 to 0.00430 mg/L representing 24% to 43% of nominal value. Although relatively consistent, some of the measured concentrations were outside the ±20% of the mean measured concentration. The BCF values have therefore been calculated using the timeweighted mean measured concentration. This was calculated to be 0.00344 mg/L.

A plateau, and hence steady state, was considered to have been achieved between Days 3 and 13 of the uptake phase. As such, steady state calculations were based on the mean results from Days 3, 6, 9 and 13 of the uptake phase.

Mean measured concentrations in whole body fish tissues at steady state during the uptake phase was 0.614 mg/kg.

The bioconcentration factor was determined for steady state (BCFSS) based on the mean of the concentrations in the fish on Days 3, 6, 9 and 13. The BCFSS was also normalised to a 5% lipid

content (BCFSSL). The kinetic bioconcentration factor (BCFK) was determined following estimation of the uptake rate (k1) and depuration rate (k2) constants. The BCFK was corrected for growth via subtraction of the growth rate constant (kg) from the k2 (to give BCFKG), which was further normalised to a 5% lipid content (to give BCFKLG). The half life (t½) and growth corrected half life (t1/2g) were also determined.

The mean lipid content of the fish at the start and end of the uptake phase and the end of the depuration phase were 9.027, 5.998 and 7.276%, respectively.

The depuration phase was conducted over a period of 7 days. After 1 day depuration, 79% reduction in body burden was observed which increased to 99% loss after 4 days depuration. At the end of the depuration phase, Day 7, concentrations above the LOQ (0.005 mg/L) were not detected.

Description of key information

The substance was shown to have limited bioconcentration potential in fish over a 13 day exposure period, with all BCF values determined <200. The substance was rapidly eliminated from the fish with approximately 79% reduction in body burden after 1 day depuration, 99% reduction after 4 days and 100% reduction following a 7 day depuration period.

Key value for chemical safety assessment

BCF (aquatic species):

200 dimensionless