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Short-term toxicity to fish

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Endpoint:
short-term toxicity to fish
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
See attachment for justification of read-across.
Reason / purpose:
read-across source
Reason / purpose:
read-across source
Reason / purpose:
read-across source
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
ca. 180 - ca. 252 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
mortality
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
6 435 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
mortality
Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with national standard methods with acceptable restrictions
Justification for type of information:
See endpoint summary for justification of read-across.
Qualifier:
according to
Guideline:
other: Methods for Acute Toxicity Tests with Fish, Macroinvertebrates, and Amphibians, USEPA, 1975
Deviations:
not specified
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
Deviations:
not applicable
GLP compliance:
no
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: the test susbtance was added directly into the each jar and mixed by stirring

- Controls: dilution water
Test organisms (species):
Oncorhynchus mykiss (previous name: Salmo gairdneri)
Details on test organisms:
TEST ORGANISM

- Common name: rainbow trout

- Source: Fish were obtained from a commercial fish hatchery in Washington, USA

- Length at study initiation (length definition, mean, range and SD): mean length of 33 mm.

- Weight at study initiation (mean and range, SD): mean wet weight of 1.9 grams at time of study

- Method of breeding: not reported

- Feeding during test: no


ACCLIMATION

- Acclimation period: 48 h

- Acclimation conditions (same as test or not): same as test

- Type and amount of food: animals were not fed during acclimation period

- Health during acclimation (any mortality observed): 0%
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Hardness:
35 mg/L CaCO3
Test temperature:
Water temperature was maintained at 12 deg C.
pH:
The pH of the test media was not reported. However a test was also conducted with Icatlurus punctatus in similar test conditions (higher temperature) and higher test concentrations, which reported a pH range of 7.0-8.2.
Dissolved oxygen:
50-99% saturation. The DO is below the recommended OECD level of 60%.
Nominal and measured concentrations:
Nominal test concentrations were 576, 432, 324, 252, and 180 mg/l as active acid. 
Details on test conditions:
TEST SYSTEM

- Test vessel: jars

- Material, size, headspace, fill volume: 19 L glass jars filled with 15L test medium

- Aeration: no

- No. of organisms per vessel: 10

- No. of vessels per concentration (replicates): 3

- No. of vessels per control (replicates): 3


TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: well water

- Culture medium different from test medium: same

- Intervals of water quality measurement: DO and temperature were measured at 0, 48 and 96 hours in the highest, middle and lowest test concentration exposures and found to be acceptable. 


OTHER TEST CONDITIONS

- Adjustment of pH: not reported

- Photoperiod: not reported

- Light intensity: not reported

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mortality every 24 h


TEST CONCENTRATIONS

- Spacing factor for test concentrations: 1.35

- Range finding study: yes, details not provided
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
ca. 180 - ca. 252 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
mortality
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
180 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
mortality
Reported statistics and error estimates:
LC50 values and 95% confidence intervals determined by regression analysis of concentrations expressed as logarithms and mortality expressed as probits.

Result expressed as nominal concentration. Properties of the test  substance and evidence from other studies (where concentrations were measured) indicate that nominal and measured concentrations are likely to be in good agreement.

Percentage mortality at each nominal test concentration:

 Concentration (mg/L)  Mortality at 96 h (%)
 Conrtol
180 
252  100 
324  100 
432  100 
576  100 



24 hr LC50: 252 (203-313) mg/L 
48 hr LC50: >180<252 mg/L

Validity criteria fulfilled:
no
Remarks:
DO was low
Conclusions:
A reliable 96 h LC50 value of 180-252 mg/L has been determined for the effects of the test substance on the mortality of the freshwater fish Salmo gairdneri (new name: Oncorhynchus mykiss). The results should however be treated with caution as the DO levels decreased to 50%, while the concentrations at which this occured are not reported. The result is considered valid as the controls mortality was 0%.
Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with national standard methods with acceptable restrictions
Justification for type of information:
See endpoint summary for justification of read-across.
Qualifier:
according to
Guideline:
other: Methods for Acute Toxicity Tests with Fish, Macroinvertebrates, and Amphibians, USEPA, 1975
Deviations:
not specified
Qualifier:
according to
Guideline:
EPA OPPTS 850.1075 (Freshwater and Saltwater Fish Acute Toxicity Test)
Deviations:
not applicable
GLP compliance:
no
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: appropriate amounts of test substance were directly added to the vessels

- Controls: dilution water only
Test organisms (species):
Cyprinodon variegatus
Details on test organisms:
TEST ORGANISM

- Common name: sheepshead minnow

- Source: collected from stocked ponds at the testing laboratory 

- Length at study initiation (length definition, mean, range and SD): 15-20 mm standard length

- Method of breeding: not reported


ACCLIMATION

- Acclimation period: a minimum of 7 days before testing

- Acclimation conditions (same as test or not): not reported (only "acclimation to laboratory conditions" reported)

- Type and amount of food: not reported

- Health during acclimation (any mortality observed): <1%
Test type:
static
Water media type:
saltwater
Limit test:
no
Total exposure duration:
96 h
Test temperature:
Water temperature was maintained at 20 +/- 1 degree C.
pH:
The pH of the test media ranged between 6.7 and 8.3
Dissolved oxygen:
>= 58% saturation for all concentrations and control
Salinity:
25 parts per thousand
Nominal and measured concentrations:
Nominal test concentrations were 1000, 10000, 18000, 32000 and 56000 ml/l (ppm).
Details on test conditions:
TEST SYSTEM

- Test vessel: jars

- Type (delete if not applicable): open

- Material, size, headspace, fill volume: Testing was conducted in 19 litre uncovered glass jars containing 15 litres of test medium.

- Aeration: no

- No. of organisms per vessel: 10

- No. of vessels per concentration (replicates): 1

- No. of vessels per control (replicates): 1



TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: Filtered natural sea water.

- Intervals of water quality measurement: DO and pH were measured during the study and remained within acceptable limits


OTHER TEST CONDITIONS

- Adjustment of pH: not reported

- Photoperiod: not reported

- Light intensity: not reported


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mortality, every 24 h


TEST CONCENTRATIONS

- Spacing factor for test concentrations: 2 and 10

- Range finding study: not reported
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
6 435 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
mortality
Reported statistics and error estimates:
Test concentrations were converted to logarithms and corresponding percentage mortalities to probits. LC50 values were then determined by linear regression.

Table 1. Mortality of fish during 96 h exposure.

 Nominal concentration (u/l; ppm)     Mortality (%)      
 24 h  48 h  96 h
 Control  0  0  0
 1 000  0  0  0
 10 000  0  0  0
 18 000  0  10  10
 32 000  60  60  60
 56 000  100  100  100

Result expressed as nominal concentration. Properties of the test substance and evidence from other studies (where
concentrations were measured) indicate that nominal and measured concentrations are likely to be in good agreement.

24 hr LC50: 5377 mg/l (30,299 ppm)


48 hr LC50:

5377 mg/l (30,299 ppm)

96 hr LC50: 5377 mg/l (30,299 ppm)

The results reported have been corrected for active acid content (18%) and density (1.18).

Validity criteria fulfilled:
yes
Conclusions:
A reliable 96 h LC50 value of 6435 mg active acid/l has been determined for the effects of DTPMP acid towards the mortality of the marine fish Cyprinodon variegatus.

Description of key information

96 h LC50 180 mg active acid/L (r-a) Salmo gairdneri (new name: Oncorhynchus mykiss)

96 h LC50 6435 mg active acid/L (r-a) Cyprinodon variegatus

Key value for chemical safety assessment

LC50 for freshwater fish:
180 mg/L
LC50 for marine water fish:
6 435 mg/L

Additional information

Freshwater

Data on short term toxicity of DTPMP Na salts to freshwater fish are available, however since the data is related to active acid content and it is possible to freely read-across from DTPMP acid (CAS 15827-60-8) to the sodium salt and the lowest LC50 is represented by data on the acid, this has been read-across.

A reliable 96 h LC50 value of 180-252, ca. 216 mg/L has been determined for the effects of DTPMP on the mortality of the freshwater fish Salmo gairdneri (new name: Oncorhynchus mykiss) (EG&G 1976a). The dissolved oxygen levels decreased down to 50%, while the concentrations at which this occured are not reported, the test is considered valid as the controls mortality was 0%. This is the lowest reliable value and has been selected as key. The study was conducted on a neutralised form (pH 7) of DTPMP acid.

The results of tests conducted on DTPMP and its salts are directly comparable, because the substance will fully dissociate in solution and the ionisation state will depend only on the pH of the test medium. The counterion is not considered to contribute to effects in fish. At environmentally-relevant pH values, DTPMP will be ionised typically 6-8 times, and will form stable complexes with metal ions.

Here, the value of 216 mg equivalent active salt/L may be directly read-across. It is convenient to convert the result into units of mg DTPMP Na salt/L at relevant conditions of pH by considering the ionisation state of DTPMP (CAS 15827-60-8) at the 216 mg/L concentration.

The pH range of the test medium is thought to be around 7. At this pH DTPMP is ionised 7 times (pKa7= pH 7.23), hence the calculation is to determine the concentration of DTPMP Na which would be equivalent to 216 mg active acid/L. In the calculation we also remove the number of hydrogen atoms substituted by the sodium salt from the MW of DTPMP, in this case 7.

The 96 h LC50 for DTPMP acid is 216 mg/L, which is equivalent to a 96 h LC50 value of 216 * 1.26 = 270 mg/L DTPMP Na

[using MW(DTPMP-7Na)/MW(DTPMP) = 573.2+((21.982-1.008)*7) / 573.2= 1.26

 

Other short-term toxicity studies reported LC50 values in the range 576 to 5377 mg active acid/L. While a prolonged study (14 d) determined an LC50 value of >262 mg active acid/L and a NOEC of 139 mg active acid/L. All of these studies indicate the very low short-term toxicity of DTPMP towards fish.

Marine

No data on short term toxicity of DTPMP Na salts to marine fish are available. However, a reliable 96 h LC50 value of 6435 mg active acid/l has been determined for the effects of DTPMP acid (CAS 15827-60-8) towards the mortality of the marine fish Cyprinodon variegatus (EG&G 1976b).

Here, the value of 6435 mg equivalent active acid/L may be directly read-across. It is convenient to convert the result into units of mg DTPMP Na salt/L at relevant conditions of pH by considering the ionisation state of DTPMP (CAS 15827-60-8) at the 6435 mg/L concentration.

The pH range of the test medium is thought to be around 7. At this pH DTPMP is ionised 7 times (pKa7= pH 7.23), hence the calculation is to determine the concentration of DTPMP Na which would be equivalent to 216 mg active acid/L. In the calculation we also remove the number of hydrogen atoms substituted by the sodium salt from the MW of DTPMP, in this case 7.

The 96 h LC50 for DTPMP acid is 6435 mg/L, which is equivalent to a 96 h LC50 value of 6435 * 1.26 = 8100 mg/L DTPMP Na

[using MW(DTPMP-7Na)/MW(DTPMP) = 573.2+((21.982-1.008)*7) / 573.2= 1.26