1-[(4-chlorophenyl)methyl]-1-cyclopentyl-3-phenylurea

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:

1982

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Qualifier:

no guideline followed

Principles of method if other than guideline:

Although the study was carried out before the introduction of GLP and the report thus contains no GLP statement, the determined BCF factor is acceptable.

GLP compliance:

no

Remarks:

older study, predates mandatory GLP

Radiolabelling:

no

Details on sampling:

- Sampling intervals/frequency for test organisms: Two carp were collected at 3, 7, 14, 21 and 28 days.
- Sampling intervals/frequency for test medium samples: Water was collected form aquarium every day during the exposure period.
- Sample storage conditions before analysis: The surface of fish body is wiped lightly with gauze and each fish was accurately weighed, and stored frozen at
- 20°C until analysis. After the 28-day exposure, pencycuron was stopped, and the remaining carp were kept into pencycuron-free water and collected at 3, 7 and 14 days.
- Details on sampling and analysis of test organisms and test media samples (e.g. sample preparation, analytical methods):
Fish
The whole body of each test fish was cut with scissors and after adding 5 g of Celite 545, blended with 80 mL of acetonitrile in a Waring Blendor for 5 min and then filtered under vacuum. The residue was extracted again with acetonitrile by blending. After filtration, all the filtrates were combined and evaporated on a rotary evaporator in vacuo at about 40°C to remove most acetonitrile. The remaining aqueous solution was transferred to a separatory funnel with 150 mL of 20% sodium chloride solution and extracted with two 100 ml portions of ethyl acetate. The combined ethyl acetate was dried over anhydrous sodium sulfate and evaporated just to dryness. The residue was dissolved in 30 ml of n-hexane and partitioned with two 50 mL portions of acetonitrile. The acetonitrile phase was combined and evaporated just to dryness. The residue was dissolved in 1 mL of dimethyl sulfoxide dried over molecular sieve 5A and methylated with sodium hydride and methyl for GLC analysis.

Water
Five hundred milliliter of water was collected and extracted with two 100 mL portions of chloroform after adding 50 g of ammonium sulfate. The extracts were combined, dried over anhydrous sodium sulfate and evaporated in vacuo. The residue was dissolved in 5 mL of chloroform for HPLC analysis.

Vehicle:

yes

Remarks:

dioctyl phthalate

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

Two hundred milligram of pencycuron, followed adding 4g of hydrogenated castor oil NIKKOL HCO-100 (NIKKO Chemical Co.,) and 4g of dioctyl phthalate was mixed with a glass motor and diluted to 10 L of dechlorinated water. Twenty ppm of pencycuron solution was used as stock solution of the test compound and prepared every other day.

The apparatus was carried out with a continuous flow water system. The stock solution containing 20 ppm of pencycuron was taken up from a tank with a micropump (Tokyo Rika Kiki MP-1001) at a rate of 3 ml/min, diluted with 600 ml/min of dechlorination of water aerated through active carbon and introduced into a 100 L glass aquarium. The test concentration of pencycuron in the aquarium was 0.1 ppm and the test water was maintained at 25±2°C.

Test organisms (species):

Cyprinus carpio

Details on test organisms:

TEST ORGANISM
- Common name: Carp (Cyprinus carpio LINNE)
- Weight at study initiation: 40 g
- Lipid content at test initiation: 4.0%

ACCLIMATION
- Acclimation period: 7 days
- Acclimation conditions (same as test or not): After sterilization, the twenty carp are acclimated in a 100 L glass aquarium at 25±2°C for 7 days before test.
- Type and amount of food: They were fed on proper quantity of pelled feed.
- Feeding frequency: 1 to 2 times daily.

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

other: A 100- L glass aquarium was used, but the water media was not specified.

Total exposure / uptake duration:

28 d

Total depuration duration:

14 d

Test temperature:

25 ± 2°C

pH:

6.7

Dissolved oxygen:

6.0 to 6.3 ppm

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 L glass aquarium
- Aeration: water aerated through active carbon

Nominal and measured concentrations:

Nominal concentration: 0.1 ppm
Measured concentration: 0.084 ppm

Reference substance (positive control):

no

Details on estimation of bioconcentration:

The BCF of pencycuron in carp was 80 to 226 during 28-day exposure period. When pencycuron was stopped and the water was changed clean water, the residue concentration of pencycuron in carp decreased. Three days after the withdrawing, the residue concentration diminished about one tenth in comparison with the plateau level and then pencycuron in carp was not detected at 7 days.

Key result

Conc. / dose:

0.084 other: ppm

Temp.:

25 °C

pH:

6.7

Type:

BCF

Value:

226 dimensionless

Basis:

whole body d.w.

Time of plateau:

7 d

Remarks on result:

other: BCF based on measured concentration

Metabolites:

The carp after 28-day exposure was attempted to determine the metabolites of pencycuron. As a result of GLC analysis by co-chromatography, 1-(p-chlorobenzyl)-3-(p-hydroxyphenyl) urea as metabolite was detected from carp body (0.07 ppm), but other metabolites were not found.

Details on results:

During the experiment, no abnormal signs of general appearance and behaviour for test carp were observed in the aquarium. Dissolved oxygen concentration (D.O.) and pH were 6.0 to 6.3 ppm and 6.7, respectively.

Recovery experiments were carried out on water and carp, and the results are shown in Table 1. Satisfactory recoveries of pencycuron were obtained, more than 98% from water and 80% from fish.

Table 2 presents the accumulation and bioconcentration factor (BCF residue concentration in carp / concentration in water ) of pencycuron in whole body of carp. During the exposure period, the actual water concentration of pencycuron in aquarium were obtained more than 80% for the nominal concentration of 0.1 ppm, and the average of water concentration for 28 days exposure was 0.084 ppm. The pencycuron in carp was approximately 10 ppm in 3 days after exposure, 13 ppm in 7 days, and it reached plateau.

The water solubility of pencycuron was 0.5 ppm at 20°C. The partition coefficient between n-octanol and water (PC) was measured in accordance with Chiou et al. method and logarithm PC of pencycuron was 4.82.

From this experiment, the water solubility and log PC of pencycuron were 0.5 ppm and 4.82, respectively, but the maximum BCF in carp was only 226. In the case of pencycuron, no correlation between the BCF of pencycuron in carp and its water solubility or n-octanol/water partition coefficient was shown.

See "Attachments" in "Overall remarks, attachments" for the tables.

Validity criteria fulfilled:

yes

Conclusions:

The carp, Cyprinus carpio L, were continuously exposed to pencycuron for 28 days period at the concentration of 0.1 ppm. Pencycuron in fish and water samples were determined throughout the 28-day exposure period and 14-day withdrawal period. Fish were actually exposed to levels of 0.084 ppm during experimental period. The accumulated residue levels of pencycuron in carp reached a maximum residue plateau within 7 days. The carp showed a maximum bioconcentration factor (residue concentration in carp / concentration in water ) of 226 during exposure period. During the withdrawal period, approximately 90% of pencycuron found were excreted within 3 days. No metabolites of pencycuron were found from carp.

Executive summary:

The carp, Cyprinus carpio L, were continuously exposed to pencycuron for 28 days period at the nominal concentration of 0.1 ppm. Pencycuron in fish and water samples were determined throughout the 28-day exposure period and 14-day depuration period. The measured concentration of pencycuron in Cyprinus carpio L was 0.084 ppm. A maximum bioconcentration factor (BCF) of 226 was reported in the whole fish during exposure period.

Description of key information

Test species	Result	Assessment	Reference
Cyprinus carpio	28-d BCF = 226 (whole fish)	Key study	Oyama et al (1982)

Key value for chemical safety assessment

BCF (aquatic species):

226 dimensionless