1,2,3-trichloropropane

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

fish, juvenile growth test

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Exposure from May 30, 1996 to September 28, 1997. Sacrifice Dates: March 12 (interim evaluation group) or September 29 (core and stop-exposure groups), 1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Meets generally accepted scientific standards and is described in sufficient detail. 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:

Groups of 220 guppy fry (two replicates of 110) were exposed 1,2,3-trichloropropane in a flow-through system to each of four nominal concentrations, 0, 4.5, 9.0 and 18.0 mg/L. The overall study durations were 16 months. At the start of the test, animals were distributed randomly into groups of equal numbers among the exposure chambers. Nine months after initiation of exposure, all treatment and control fish were removed from the test aquaria and counted. Ten guppies from each group replicate were sacrificed for histopathological analysis. The remaining fish from each group were distributed into either continuing exposure groups or stop-exposure groups in chemical-free water. This distribution was performed such that roughly two-thirds of the remaining fish from each group were placed in continuing exposure groups and the remaining third were placed into stop-exposure groups for the remainder of the studies. The stop-exposure component was added since this was a new system for NTP and for fish studies, and it was thought that stopping the exposure at 9 months and transferring to exposure chemical-free aquaria would allow for better survival and tumor development. The sex of guppies was not determined until histopathological analysis.

GLP compliance:

yes

Remarks:

- conducted in compliance with Food and Drug Administration Good Laboratory Practice Regulations (21 CFR, Part 58). In addition, as records from the studies were submitted to the NTP Archives, these studies were audited retrospectively.

Analytical monitoring:

yes

Details on sampling:

1,2,3-trichloropropane in the exposure aquaria was monitored using GC, approximately 3 times each week. Duplicate samples were analyzed from each aquarium.

Vehicle:

no

Test organisms (species):

Poecilia reticulata

Details on test organisms:

TEST ORGANISM
- Common name: Guppy
- Source: established Gulf Coast Research Laboratory GCRL cultures (Guppy cultures originating from Aqua World (St. Louis, MO, U.S.A) had been maintained at GCRL for more than 10 years prior to the initiation of the studies. Brood cultures were established from the GCRL cultures for the purpose of producing fry for use in these studies.)
- Age at study initiation: Guppy fry were 14 days old at test initiation.

FEEDING DURING TEST
Aqua-Tox (Specialized Formula) Flake (Ziegler Brothers, Inc., Gardners, PA, U.S.A.) once a day until 24 hours before sacrifice and rehydrated brine shrimp (Artemia) larvae (Aquarium Products, Glen Burnie, MD. U.S.A.) once daily except during the last week of the study.

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

487 d

Remarks on exposure duration:

9 months (stop-exposure and interim evaluation groups) or 16 months (core group)

Post exposure observation period:

Nine months after the test initiation, approximately one-third of the fish from each exposure group were transferred from the exposure system to aquaria receiving 1,2,3-trichloropropane-free water under flow-through conditions. They remained in this system for an additional 7 months.

Test temperature:

26 ± 0.3°C

pH:

8.8 ± 0.2

Dissolved oxygen:

≥ 40 % saturation

Nominal and measured concentrations:

Nominal exposure concentrations of 4.5, 9.0 and 18.0 mg/L resulted in actual exposure concentrations of 4.4±0.4 (CV 9.3), 8.8± 0.7 (CV 8.4) and 18.2± 1.6 (CV 8.9) mg/L 1,2,3-trichloropropane, respectively.

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type: aquaria were covered with polycarbonate covers
- Material, size, headspace, fill volume: First, glass aquaria (48 cm long, 38 cm wide, and 24 cm high) containing approximately 35 L of test solution were used. To adjust for loss of fish volume at 9 months, fish were moved to smaller aquaria containing approximately 21 L of test solution (44 cm long, 25 cm wide and 23 cm high. A water depth of 19 cm was maintained by a drain siphon that removed water from near the bottom of each aquarium. Thus 4-5 cm headspace were maintained.
- Type of flow-through: water partitioner, timer-regulated
- Renewal rate of test solution: at least 5 volume additions per day
- No. of organisms per vessel: 110
- No. of vessels per concentration (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Aged, aerated, carbon-filtered, unchlorinated well water (University of Southern Mississippi, Ocean Springs, MS, U.S.A.)

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light / 8 hours dark with 30 minute transition to simulate dawn and dusk.
- Light intensity: Room fluorescent light

EFFECT PARAMETERS MEASURED:
Observed twice daily at intervals at least 6 hours apart. Body weights and lengths were recorded at necropsy.

RANGE-FINDING STUDY
The results of previous studies of life span and dose range-finding studies (2-day static, 7-day flow-through, and 28-day range-finding studies) were used to determine the overall study lengths and the individual study dose ranges.

Reference substance (positive control):

not required

Remarks:

since 2,2-Bis(bromomethyl)-1,3-propanediol, Nitromethane, and 1,2,3-Trichloropropane were tested in parallel.

Duration:

6 mo

Dose descriptor:

NOEC

Effect conc.:

8.8 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

6 mo

Dose descriptor:

LOEC

Effect conc.:

18.2 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

7 mo

Dose descriptor:

LOEC

Effect conc.:

4.4 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

16 mo

Dose descriptor:

LOEC

Effect conc.:

4.4 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

other: carcinogenicity

Reported statistics and error estimates:

Survival Analyses
The probability of survival was estimated by the product- limit procedure of Kaplan and Meier (1958). Possible dose-related trends were tested with Tarone’s (1975) life table test; pairwise comparisons with the control group were made with Cox’s (1972) method for testing the equality of two groups.
Incidence of Lesions
For each combination of sex, species, and chemical, tank effects were tested using Fisher’s exact test for the neoplasm of interest.
Analysis of Lesions
Dose-related trends were tested with the Cochran-Armitage trend test (Armitage 1971; Gart et al 1979). When a small number of lesions were present and they were disproportionately distributed at one extreme of the dose range, an exact permutation trend test was used (Plackett 1981). Fisher’s exact test was used for pairwise comparisons of each dose group to the control group. P-values for the trend tests and Fisher’s exact test are one sided.
Analysis of Continuous Variables
Body weight and body length, which have approximately normal distributions, were analyzed by analysis of variance followed by Dunnett’s multiple comparison procedure (1955) to compare each dose group to the control group.

Survival

The survival of exposed guppies was less than that of the control group at 9 months. Reduced survival was evident at 6 months in the 18.0 mg/L groups, and at 7 months in the 4.5 and 9.0 mg/L groups (data not shown). Survival was significantly reduced in the 18.0 mg/L core study group within one month of the 9-month interim evaluation (data not shown), and mortality in this group after reallocation at 9 months was 42.6% at study termination. The results are summarized in the following Table:

	Nominal Concentration of TCP [mg/L]
	0	4.5	9.0	18.0
Animals initially in study	220	220	220	220
Died before 9-month evaluation	1.4 %	6.4 %	7.7 %	14.5 %
Died after reallocation Core study Stop-exposure study	3.8 % 4.5 %	7.3 % 12.9 %	6.6 % 6.6 %	42.6 % 16.7 %

Exposure Concentrations, Body Lengths, and Body Weights

Nominal exposure concentrations of 4.5, 9.0, and 18.0 mg/L (analyzed three times per week) resulted in actual exposure concentrations of 4.4, 8.8, and 18.2 mg/L 1,2,3-trichloropropane, respectively. Guppies in the 18.0 mg/L core study group were significantly longer and weighed more than the controls. Fish in the 18.0 mg/L stop-exposure group also weighed more than the controls. Mortality of fish during the study resulted in unequal numbers of individuals distributed to core study and stop-exposure aquaria at 9 months. This appears to have influenced the length and weight of fish measured at study termination (i.e., the smaller tank population allowed the fish to grow more). Observed differences in weight and length between controls and 18.0 mg/L fish may have been an artefact of the reduced fish numbers in the 18.0 mg/L aquaria.

Pathology

1,2,3-trichloropropane gave in all concentration tested a positive carcinogenic response.

Liver (9-Month Interim Evaluation): Multiple hepatocellular adenomas occurred in one 4.5 mg/L male, and one hepatocellular adenoma occurred in a control male. No other hepatocellular neoplasms were observed; consequently, the hepatocellular adenomas seen in the one exposed male were considered to be incidental and unrelated to exposure. Liver neoplasms were not found in females at 9 months.

Liver (Core Study): Increased incidences of cholangiocellular (bile duct) and hepatocellular neoplasms were observed in 18.0 mg/L males and 9.0 and 18.0 mg/L females as compared with controls. Cholangiocarcinomas in 18.0 mg/L females metastasized to intestine, mesentery, and spleen. Combined incidences of hepatocellular adenoma and multiple hepatocellular adenoma were increased in exposed groups of males as compared with controls. In addition, hepatocellular carcinoma occurred with greater incidence in 18.0 mg/L males than in the controls. Microscopically, these liver lesions appeared similar to those previously described.

Incidences of basophilic focus were increased in 9.0 and 18.0 mg/L males as compared with controls. The incidences of granuloma and cystic degeneration in exposed males, and granuloma in 18.0 mg/L females were less than those in the controls. Mononuclear cell infiltrate consisted of multiple, small, scattered aggregates of mixed mononuclear inflammatory cells, generally macrophages and lymphocytes. The microscopic appearances of granuloma and cystic generation were similar to those described previously. The decreased incidences of granuloma, mononuclear cell infiltrate, and cystic degeneration may have been secondary to the presence of other exposure-related lesions that obscured the presence of these lesions.

Liver (Stop-Exposure Study): Increased incidences of cholangiocellular (bile duct) neoplasms were observed in 18.0 mg/L females, and increased incidences of hepatocellular neoplasms occurred in 18.0 mg/L males.

Cholangiomas occurred in a few exposed females, including controls. However, a few cholangiocarcinomas occurred in the 18.0 mg/L females only, and the combined incidence of cholangioma and cholangiocarcinoma was greater in the 18.0 mg/L females than in the controls. One of the cholangiocarcinomas in females metastasized to the peritoneum. A single cholangiocarcinoma occurred in a 18.0 mg/L male. Incidences of bile duct hyperplasia were slightly increased in the 9.0 mg/L males as compared with controls.

Hepatocellular adenoma occurred with a greater incidence in 18.0 mg/L males, and multiple hepatocellular adenoma and hepatocellular carcinoma occurred with greater incidence in 18.0 mg/L males compared to controls. Incidences of hepatocellular neoplasms in females were similar across the control and exposed groups. Basophilic focus occurred with slightly greater incidences in exposed groups of males and females as compared with controls. Eosinophilic focus occurred in a small number of exposed males but not in control males. Incidences in females were similar across groups. Microscopically, eosinophilic foci appeared similar to those previously described.

Validity criteria fulfilled:

yes

Conclusions:

1,2,3-trichloropropane was found carcinogenic al all concentrations tested. Long term observations from growing juvenile fish were reported as well. In order to derive a NOEC comparable to standard tests for this endpoint the 6 month evaluation was the only one delivering a NOEC based on mortality being 8.8 mg/L.

Executive summary:

The survival of exposed guppies was less than that of the control group at 9 months. Reduced survival was evident at 6 months in the 18.0 mg/L groups and at 7 months in the 4.5 and 9.0 mg/L groups. Survival was significantly reduced in the 18.0 mg/L core study group within 1 month of the 9-month interim evaluation, and mortality in this group was 42.6% between 9 months and study termination. Nominal exposure concentrations of 4.5, 9.0, and 18.0 mg/L resulted in actual exposure concentrations of 4.4, 8.8, and 18.2 mg/L 1,2,3-trichloropropane, respectively. Guppies in the 18.0 mg/L core study group were significantly longer and weighed more than the controls. Fish in the 18.0 mg/L stop-exposure group also weighed more than the controls. Mortality of fish during the study resulted in unequal numbers of individuals distributed to core study and stop-exposure aquaria at 9 months. This appears to have influenced the length and weight of fish measured at study termination (i.e., the smaller tank population allowed the fish to grow more). Observed differences in weight and length between controls and 18.0 mg/L fish was most likely an artifact of the reduced numbers of fish in the 18.0 mg/L aquaria.

At 9 months, multiple hepatocellular adenomas occurred in one 4.5 mg/L male, and one hepatocellular adenoma occurred in a control male. In the core study, increased incidences of cholangiocellular (bile duct) and hepatocellular neoplasms occurred in exposed groups of males and females. Cholangioma and cholangiocarcinoma were seen in several exposed males and females. In the stop-exposure study, increased incidences of hepatocellular neoplasms occurred in 18.0 mg/L males and increased incidences of cholangiocellular (bile duct) neoplasms occurred in 18.0 mg/L females.

Under the conditions of these waterborne studies, 1,2,3-trichloropropane at concentrations of up to 18 mg/L for 16 months was considered carcinogenic for male and female guppies based on increased incidences of a variety of liver neoplasms.

Reference 2

Endpoint:

adult fish: sub(lethal) effects

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Exposure from May 30, 1996 to June 30, 1997. Sacrifice Dates: March 11 (interim evaluation group) or July 1, (core and stop-exposure groups), 1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Meets generally accepted scientific standards and is described in sufficient detail. 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:

Groups of 340 medaka fry (two replicates of 170) were exposed 1,2,3-trichloropropane in a flow-through system to each of four nominal concentrations, 0, 4.5, 9.0 and 18.0 mg/L. The overall study durations were 13 months. At the start of the test, animals were distributed randomly into groups of equal numbers among the exposure chambers. Nine months after initiation of exposure, all treatment and control fish were removed from the test aquaria and counted. Ten medaka from each group replicate were sacrificed for histopathological analysis. The remaining fish from each group were distributed into either continuing exposure groups or stop-exposure groups in chemical-free water. This distribution was performed such that roughly two-thirds of the remaining fish from each group were placed in continuing exposure groups and the remaining third were placed into stop-exposure groups for the remainder of the studies. The stop-exposure component was added since this was a new system for NTP and for fish studies, and it was thought that stopping the exposure at 9 months and transferring to exposure chemical-free aquaria would allow for better survival and tumour development. The sex of medaka was not determined until histopathological analysis.

GLP compliance:

yes

Remarks:

- conducted in compliance with Food and Drug Administration Good Laboratory Practice Regulations (21 CFR, Part 58). In addition, as records from the studies were submitted to the NTP Archives, these studies were audited retrospectively.

Analytical monitoring:

yes

Details on sampling:

1,2,3-trichloropropane in the exposure aquaria was monitored using GC, approximately 3 times each week. Duplicate samples were analyzed from each aquarium.

Vehicle:

no

Test organisms (species):

Oryzias latipes

Details on test organisms:

TEST ORGANISM
- Common name: Medaka
- Source: established Gulf Coast Research Laboratory GCRL cultures (medaka cultures originating from Carolina Biological Supply (Burlington, NC, U.S.A.) had been maintained at GCRL for more than 10 years prior to the initiation of the studies. Brood cultures were established from the GCRL cultures
for the purpose of producing fry for use in these studies.)
- Age at study initiation: Medaka fry were 14 days old at test initiation.

FEEDING DURING TEST
Aqua-Tox (Specialized Formula) Flake (Ziegler Brothers, Inc., Gardners, PA, U.S.A.) once a day until 24 hours before sacrifice and rehydrated brine shrimp (Artemia) larvae (Aquarium Products, Glen Burnie, MD. U.S.A.) once daily except during the last week of the study.

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

386 d

Remarks on exposure duration:

9 months (stop-exposure and interim evaluation groups) or 13 months (core group)

Post exposure observation period:

Nine months after the test initiation, approximately one-third of the fish from each exposure group were transferred from the exposure system to aquaria receiving 1,2,3-trichloropropane-free water under flow-through conditions. They remained in this system for an additional 4 months.

Test temperature:

26 ± 0.3°C

pH:

8.8 ± 0.2

Dissolved oxygen:

≥ 40 % saturation

Nominal and measured concentrations:

Nominal exposure concentrations of 4.5, 9.0 and 18.0 mg/L resulted in actual exposure concentrations of 4.6±0.3 (CV 7.7), 9.2± 0.6 (CV 6.6) and 18.0± 1.9 (CV 10.5) mg/L 1,2,3-trichloropropane, respectively.

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type: aquaria were covered with polycarbonate covers
- Material, size, headspace, fill volume: First, glass aquaria (48 cm long, 38 cm wide, and 24 cm high) containing approximately 35 L of test solution were used. To adjust for loss of fish volume at 9 months, fish were moved to smaller aquaria containing approximately 21 L of test solution (44 cm long, 25 cm wide and 23 cm high. A water depth of 19 cm was maintained by a drain siphon that removed water from near the bottom of each aquarium. Thus 4-5 cm headspace were maintained.
- Type of flow-through: water partitioner, timer-regulated
- Renewal rate of test solution: at least 5 volume additions per day
- No. of organisms per vessel: 170
- No. of vessels per concentration (replicates): 2


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Aged, aerated, carbon-filtered, unchlorinated well water (University of Southern Mississippi, Ocean Springs, MS, U.S.A.)

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light/8 hours dark with 30 minute transition to simulate dawn and dusk.
- Light intensity: Room fluorescent light


EFFECT PARAMETERS MEASURED:
Observed twice daily at intervals at least 6 hours apart. Body weights and lengths were recorded at necropsy.

RANGE-FINDING STUDY
The results of previous studies of life span and dose range-finding studies (2-day static, 7-day flow-through, and 28-day range-finding studies) were used to determine the overall study lengths and the individual study dose ranges.

Reference substance (positive control):

not required

Remarks:

since 2,2-Bis(bromomethyl)-1,3-propanediol, Nitromethane, and 1,2,3-Trichloropropane were tested in parallel.

Duration:

9 mo

Dose descriptor:

NOEC

Effect conc.:

4.6 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

9 mo

Dose descriptor:

LOEC

Effect conc.:

9.2 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

13 mo

Dose descriptor:

LOEC

Effect conc.:

4.6 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

other: carcinogenicity

Reported statistics and error estimates:

Survival Analyses
The probability of survival was estimated by the product-limit procedure of Kaplan and Meier (1958). Possible dose-related trends were tested with Tarone’s (1975) life table test; pairwise comparisons with the control group were made with Cox’s (1972) method for testing the equality of two groups.
Incidence of Lesions
For each combination of sex, species, and chemical, tank effects were tested using Fisher’s exact test for the neoplasm of interest.
Analysis of Lesions
Dose-related trends were tested with the Cochran-Armitage trend test (Armitage 1971; Gart et al 1979). When a small number of lesions were present and they were disproportionately distributed at one extreme of the dose range, an exact permutation trend test was used (Plackett 1981). Fisher’s exact test was used for pairwise comparisons of each dose group to the control group. P-values for the trend tests and Fisher’s exact test are one sided.
Analysis of Continuous Variables
Body weight and body length, which have approximately normal distributions, were analyzed by analysis of variance followed by Dunnett’s multiple comparison procedure (1955) to compare each dose group to the control group.

Survival

Survival in the 9.0 and 18.0 mg/L groups indicated that 1,2,3-trichloropropane was chronically toxic to the medaka; reduced survival was evident beginning at 9 months of exposure. Mortality in the 18.0 mg/L core study group was 26.3% and mortality in the 9.0 mg/L group was 17.3% between 9 months and study termination at 13 months. Survival was also reduced in stop-exposure fish from the 9.0 and 18.0 mg/L groups at the end of the study. The results are summarized in the following Table.

	Nominal Concentration of TCP [mg/L]
	0	4.5	9.0	18.0
Animals initially in study	340	340	340	340
Died before 9-month evaluation	3.2 %	1.8 %	4.7 %	8.2 %
Died after reallocation Core study Stop-exposure study	5.4 % 3.9 %	8.7 % 10.6 %	17.3 % 14.0 %	26.3 % 18.9 %

Exposure Concentrations, Body Lengths, and Body Weights

Nominal exposure concentrations of 4.5, 9.0, and 18.0 mg/L resulted in actual exposure concentrations of 4.6, 9.2, and 18.0 mg/L 1,2,3-trichloropropane, respectively. Core study medaka in the 18.0 mg/L group were both longer and weighed more than the controls at the end of the study. At 9 months, the lengths and weights of medaka in the 9.0 and 18.0 mg/L groups were significantly increased. Mortality of fish during the study resulted in unequal numbers of individuals distributed to core study and stop-exposure aquaria at 9 months. This appears to have influenced the length and weight of fish measured at study termination (i.e. the smaller tank population allowed the fish to grow more). Observed differences in weight and/or length between controls and 9.0 or 18.0 mg/L fish may have been an artefact of the reduced numbers of fish in these exposure aquaria.

Pathology

This section describes the statistically or biologically noteworthy changes in incidences of neoplasms and/or nonneoplastic lesions of the liver, gallbladder, kidney, and thyroid tissue.

Liver (9-Month Interim Evaluation): The incidences of cholangiocarcinomas in 9.0 and 18.0 mg/L males were significantly increased at 9 months. Small numbers of cholangiocarcinomas occurred with similar incidences in each of the exposed female groups, and a cholangioma occurred in one 4.5 mg/L female. A hepatocholangiocarcinoma, a malignant liver neoplasm consisting of both neoplastic cholangiocellular (bile duct) and hepatocellular components, occurred in one 4.5 mg/L male, a hepatocellular adenoma occurred in one 18.0 mg/L male, and a hepatocellular carcinoma occurred in one 9.0 mg/L female. No cholangiocellular or hepatocellular neoplasms occurred in control males or females.

Liver (Core Study): Increased incidences of cholangiocellular and hepatocellular neoplasms occurred in exposed groups of males and females.

One to a few cholangiomas occurred in each of the exposed groups of males and females but not in controls. Incidences of cholangiocarcinomas were significantly increased in all exposed groups of males and females; no cholangiocarcinomas were observed in controls. Cholangiocarcinomas metastasized to a number of tissues including heart, kidney, eye, mesentery, adipose tissue, swim bladder, spleen, oesophagus, ovary, pericardial cavity, and intestine. Moreover, incidences of bile duct hyperplasia were substantially increased in exposed groups of females and 9.0 and 18.0 mg/L males as compared with controls. Incidences of hepatocellular adenoma and hepatocellular carcinoma (combined) were increased in 18.0 mg/L males and females as compared with controls. One 18.0 mg/L female had multiple hepatocellular adenomas. One hepatocellular adenoma and one hepatocellular carcinoma occurred in control females, otherwise there were no hepatocellular neoplasms in control fish. A number of hepatocholangiocarcinomas also occurred in exposed groups of males and females, but not in controls. Hepatocholangiocarcinomas metastasized to a number of tissues including oesophagus, adipose tissue, intestine, mesentery, pericardial cavity, and spleen.

Incidences of granuloma of the liver were decreased in 4.5 and 18.0 mg/L males and 18.0 mg/L females. The decreased incidences of granuloma may have been secondary to the presence of other exposure-related lesions that obscured the presence of granulomas. The incidences of cyst were lower in 18.0 mg/L males and in all exposed groups of females than in the controls. The decreased incidences of cyst may be secondary to the presence of other exposure-related lesions that obscured the presence of cysts. Microscopically, all of the liver lesions observed in this study appeared similar to those previously described.

Liver (Stop-Exposure Study): Increased incidences of cholangiocellular (bile duct) neoplasms were observed in exposed groups of males and females as compared with controls. An increased incidence of hepatocellular carcinoma was observed in 18.0 mg/L females.

Cholangiocarcinoma occurred with moderately high incidences in all groups of exposed males and females. Cholangiocarcinoma also occurred in one control female. Cholangiocarcinomas metastasized to a number of tissues including oesophagus, adipose tissue, eye, heart, kidney, mesentery, pericardial cavity, peritoneum, and spleen. Cholangioma occurred in a few exposed males and females but not in controls. Bile duct hyperplasia occurred with greater incidences in the 9.0 and 18.0 mg/L male groups than in the control group. The incidences of bile duct hyperplasia were similar in control and exposed groups of females. The incidences of cystic degeneration were higher in 9.0 and 18.0 mg/L females than in controls. Incidences of cysts were lower in exposed groups of males and females than in controls.

The decreased incidences of cysts may be secondary to the presence of other exposure-related lesions that obscured the presence of cysts.

Validity criteria fulfilled:

yes

Conclusions:

1,2,3-trichloropropane was found carcinogenic al all concentrations tested. Long term observations from growing juvenile fish were reported as well. In order to derive a NOEC comparable to standard tests for this endpoint the 9 month evaluation delivered a NOEC based on mortality being 4.6 mg/L.

Executive summary:

Survival in the 9.0 and 18.0 mg/L groups indicated that 1,2,3-trichloropropane was chronically toxic to the medaka; reduced survival was evident beginning at 9 months of exposure. Mortality in the 18.0 mg/L core study group was 26.3% and mortality in the 9.0 mg/L group was 17.3% between 9 months and study termination at 13 months. Survival was also reduced in stop-exposure fish from the 9.0 and 18.0 mg/L groups at the end of the study. Nominal exposure concentrations of 4.5, 9.0, and 18.0 mg/L resulted in actual exposure concentrations of 4.6, 9.2, and 18.0 mg/L 1,2,3-trichloropropane, respectively. At 9 months, the weights of medaka in the 9.0 and 18.0 mg/L groups were significantly increased. Core study medaka in the 18.0 mg/L group were both longer and weighed more than the controls at the end of the study. Observed differences in length and/or weight between controls and 9.0 or 18.0 mg/L fish were most likely an artefact of the reduced numbers of fish in these exposure aquaria.

The incidences of cholangiocarcinomas in the 9.0 and 18.0 mg/L groups of males were significantly increased at 9 months. In the core study, the incidences of cholangiocarcinoma were significantly increased in all exposed groups of males and females; the incidences of hepatocellular neoplasms and hepatocholangiocarcinomas were significantly increased in 18.0 mg/L medaka. In the stop-exposure study, increased incidences of cholangiocarcinoma occurred in all exposed groups of males and females. The incidence of hepatocellular carcinoma was significantly increased in 18.0 mg/L females.

At 9 months, papillary adenomas of the gallbladder occurred in two 18.0 mg/L males. No gallbladder neoplasms were seen in the controls or any of the other exposed groups. In the core study, papillary adenoma of the gallbladder occurred in a number of exposed males and females, and incidences were significantly increased in the 9.0 and 18.0 mg/L groups. In the stop-exposure study, the incidence of papillary adenoma in males exposed to 18.0 mg/L was significantly increased; papillary adenoma and carcinoma were observed in most exposed groups of males and females.

Description of key information

TCP exhibits chronic effects to fish. The NOEC assigned on the basis of 6 month exposure data.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

4.4 mg/L

Additional information

In the beginning of 2004, a draft report of toxicity tests with two fish species and 1,2,3-trichloropropane was published (NIH 2005). These studies were not included in the CICAD (OECD SIDS 2004) but robust summaries have been prepared. The NIH chose to initiate these studies in guppies (Poecilia reticulata) and medaka (Oryzias latipes) as an exploration of alternate or additional models for examining chemical toxicity and carcinogenicity. The use of small fish species in carcinogenicity testing offered potential advantages as a bioassay test system, including significant savings in cost and time over rodent studies. Groups of 220 guppies (two replicates of 110) and 340 medaka (two replicates of 170) were exposed 1,2,3-trichloropropane in a flow-through system to each of four nominal concentrations 0, 4.5, 9.0 and 18.0 mg/L. Nine months after the test initiation, approximately one-third of the fish from each exposure group were transferred from the exposure system to aquaria receiving 1,2,3-trichloropropane-free water under flow-through conditions. They remained in this system for an additional 4 months (medaka) or 7 months (guppies). Fish remaining in the exposure system continued 1,2,3-trichloropropane exposure for a total of approximately 13 months (medaka) or 16 months (guppies). Concentrations of 1,2,3-trichloropropane in the exposure aquaria were monitored using GC, approximately 3 times each week. Differences between nominal and measured concentrations were less than 3 %. After 9 months the mortality of the guppies was 1.4; 6.4; 7.7 and 14.5 % for 1,2,3-trichloropropane concentrations of 0, 4.5, 9.0 and 18.0 mg/L, respectively. Although the survival of exposed guppies was less than that of the control group at 9 months, guppies in the 18.2 mg/L study group were significantly longer and weighed more than the controls. Observed differences in weight and length between controls and 18.0 mg/L fish was most likely an artefact of the reduced fish numbers in the 18.0 mg/L aquaria (amount of food was not reduced). Under the conditions of this study, 1,2,3-trichloropropane at concentrations of up to 18 mg/L for 16 months was considered carcinogenic for male and female guppies, based on increased incidences of a variety of liver neoplasms. After 9 months the mortality of the medaka was 3.2; 1.8; 4.7 and 8.2 % for 1,2,3-trichloropropane nominal concentrations of 0, 4.5, 9.0 and 18.0 mg/L, respectively. At 9 months, the weights of medaka in the 9.0 and 18.0 mg/L groups were significantly increased. Core-study medaka in the 18.0 mg/L group were both longer and weighed more than the controls at the end of the study. Observed differences in weight and/or length between controls and 9.0 or 18.0 mg/L fish have been an artifact of the reduced fish numbers in these exposure aquaria (amount of food was not reduced). Under the conditions of this study, 1,2,3-trichloropropane at concentrations of up to 18 mg/L for 13 months was considered carcinogenic for male and female medaka, based on increased incidences of a variety of liver neoplasms and papillary adenoma of the gallbladder (OECD SIDS 2004).

NOEC derivation

Intermediary results from these studies allow the derivation of long-term NOECs based on mortality. While in the guppy study a 6 month value is conclusive for the 8.8 mg/L concentration, after 7 month all tested concentrations showed significantly reduced mortality. The medaka experiment delivers a 9 month NOEC of 4.6 mg/L. The survival in the 9.0 and 18.0 mg/L groups indicated that 1,2,3-trichloropropane was chronically toxic to the medaka in this concentrations and reduced survival was evident beginning at 9 months of exposure. Thus the lowest measured concentration of 4.6 mg/L is regarded as NOEC 9 month for the endpoint mortality in the medaka test. However - guppies were more sensitive and even if the comparable derivation of a definitive NOEC is not possible it is clear the NOEC 7 month for guppies is < 4.4 mg/L. Thus in application of the precautionary principle the value 4.4 mg/L is taken as NOEC fish, long-term. One may counter that a lower value should apply because at this level were still effects, but on the other hand the observation is much longer than the standards for this endpoint and thus for the derivation of PNEC according to the standard approaches this assigned NOEC of 4.4 mg/L is acceptable.