Ziram

Endocrine disrupter testing in aquatic vertebrates – in vivo

Administrative data

Endpoint:

fish: other

Remarks:

Fish Short-Term Reproduction Assay (screening for endocrine activity)

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD TG 229 (Fish Short Term Reproduction Assay)

Version / remarks:

2012

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: OPPTS Number 890.1350: Fish Short-Term Reproduction Assay

Version / remarks:

2009

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Ziram

EC Number:

205-288-3

EC Name:

Ziram

Cas Number:

137-30-4

Molecular formula:

C6H12N2S4Zn

IUPAC Name:

ziram

Sampling and analysis

Analytical monitoring:

yes

Remarks:

LC/MS/MS

Test solutions

Vehicle:

yes

Remarks:

Dimethylformamide (DMF)

Test organisms

Aquatic vertebrate type:

fish

Test organisms (species):

Pimephales promelas

Study design

Test type:

flow-through

Water media type:

well water

Limit test:

no

Total exposure duration:

21 d

Test conditions

Nominal and measured concentrations:

Nominal: negative control, solvent control, 0.5, 1.6 and 5.1 µg a.i./L
Mean measured: < LOQ, < LOQ, 0.22, 0.96 and 3.7 μg a.i./L

Details on test conditions:

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Endpoints that were evaluated for investigation of potential endocrine disruption of the reproductive system included fecundity, fertility, secondary sex characteristics (including tubercle), gonadosomatic index (GSI), histopathology of gonads, as well as plasma vitellogenin. Other endpoints included survival, general observations of health, wet weight and length.

Results and discussion

Any other information on results incl. tables

Treatment-related findings in this assay were observed in the high (3.7 μg a.i./L) treatment group. All GSI were in the range typical for female and male fathead minnows as indicated by the OPPTS guideline. However, in males, there was a statistically significant increase in GSI at 3.7 μg a.i./L. The sole histopathology finding in the testes of male fathead minnows related to Ziram exposure was a slight increase in mean testicular stage in the 0.96 and 3.7 μg a.i./L dose groups when compared to negative or solvent controls. This result was consistent with a significantly greater mean GSI in 3.7 μg a.i./L group males relative to controls. The mean GSI in the 0.96 μg a.i./L dose group was not elevated and there were no findings at any dose group on relative germ cell numbers, alternations in the number and sizes of non-germ cells (e.g., testicular interstitial cells and ovarian perifollicular cells) and increased degenerative changes. There is little published information concerning the biological relevance of increased testicular stage scores in male fathead minnows, and this effect is not necessarily specific for, or indicative of, reproductive endocrine disruption. Additionally, the differences were attributable to a low number of males with higher than average scores. There were no histopathology findings in the ovaries of female fathead minnows related to Ziram exposure. The prevalence and severity of oocyte atresia, numbers of post-ovulatory follicles, and mean ovarian stage scores were generally comparable among control and treated groups. To conclude, Ziram does not appear to impact the hypothalamus-pituitary-gonadal endocrine axis in fish.     Table 1: Summary of survival, fecundity, vitellogenin concentrations, secondary sex characteristics, growth, and GSI of fathead minnow following 21-day exposure to Ziram under flow through conditions. Endpoint Nominal concentration [µg a.s./L] Pooled control 0.22 0.96 3.7 Survival [%] 95.8 ± 7.7 95.8 ± 8.4 91.7 ± 9.6 95.8 ± 8.4 Cumulative number of eggs produced 2280 ± 576 2059 ± 599 2365 ± 671 1922 ± 267 Eggs/female/day 28.1 ± 7.3 25.0 ± 7.0 30.5 ± 9.7 22.9 ± 3.2 Fertilisation rate [%] 95.1 ± 2.0 94.0 ± 2.1 95.2 ± 3.1 97.6 ± 1.0 Vitellogenin concentration [ng/mL] M 6.77 x 10^3 ± 8.65 x 10^3 4.27 x 10^3 ± 5.18 x 10^3 5.17 x 10^3 ± 5.47 x 10^3 1.50 x 10^3 ± 4.48 x 10^2 F 2.57 x 10^8 ± 6.11 x 10^8 1.58 x 10^8± 2.56 x 10^8 2.90 x 10^7 ± 3.25 x 10^7 1.66 x 10^8± 2.39 x 10^8 Tubercles score M 29.8 ± 4.67 30.0 ± 6.70 28.3 ± 4.74 26.1 ± 2.78 F 0 ± 0 0 ± 0 0 ± 0 0 ± 0 Total length [mm] M 59.6 ± 2.00 60.8 ± 2.60 60.8 ± 1.56 59.9 ± 2.02 F 49.1 ± 1.11 48.8 ± 0.64 48.9 ± 0.91 48.5 ± 0.20 Wet weight [g] M 2.99 ± 0.187 3.11 ± 0.273 3.17 ± 0.273 2.75 ± 0.394 F 1.32 ± 0.107 1.31 ± 0.039 1.30 ± 0.079 1.26 ± 0.047 Gonadosomatic index M 1.13 ± 0.102 1.22 ± 0.332 1.20 ± 0.162 1.46 ± 0.154 * F 12.0 ± 1.60 11.9 ± 1.44 12.0 ± 2.63 11.5 ± 1.64 F= females, M = males * significantly different from the pooled control (p < 0.05)     Table 2: Test acceptance criteria for OECD 229 Performance criteria Outcome Criterion fulfilled the mortality in the water (or solvent) controls should not exceed 10 per cent at the end of the exposure period Survival was 95.8% in the negative and solvent control groups yes the dissolved oxygen concentration should be at least 60 per cent of the air saturation value (ASV) throughout the exposure period ≥ 68% of saturation yes the water temperature should not differ by more than ± 1.5 °C between test vessels at any one time during the exposure period and be maintained within a range of 2°C within the temperature ranges specified for the test species (25 ± 2°C for fathead minnow and medaka and 26 ± 2°C for Danio rerio) 24.9 to 25.7°C yes evidence should be available to demonstrate that the concentrations of the test substance in solution have been satisfactorily maintained within ±20% of the mean measured values Measured concentrations remained within an acceptable range for the 0.96 and 3.7 µg a.i./L treatment groups but did not for the 0.22 µg a.i./L treatment group. The coefficient of variation of the measured concentrations during the study were 29.6, 18.3 and 16.5% for the 0.22, 0.96 and 3.7 µg a.i./L treatment groups, respectively. The LOQ for the analysis was 0.250 µg a.i./L, so there were many samples for this treatment group that were <LOQ but >LOD. Since the results were within the calibration curve, they are reported but are footnoted appropriately. Since there are no endocrine related effects observed in this study, the variable measured concentrations in the 0.22 µg a.i./L treatment group does not impact the integrity of the study. yes evidence that fish are actively spawning in all replicates prior to initiating chemical exposure and in control replicates during the test. Fish were actively spawning in all replicates prior to initiating chemical exposure in those replicates, and in control replicates during the test. yes

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

For details refer to field "Any other information on results incl. tables"