Tributyl phosphate

Toxicity to soil macroorganisms except arthropods

Administrative data

Endpoint:

toxicity to soil macroorganisms except arthropods: short-term

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2020

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

publication

Title:

Tri-n-butyl phosphate induced earthworm intestinal damage by influencing nutrient absorption and energy homeostasis of intestinal epithelial cells

Author:

Yang Yang, Peng Liu, Mei Lia

Year:

2020

Bibliographic source:

Journal of Hazardous Materials 398 (2020) 122850

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 207 (Earthworm, Acute Toxicity Tests)

Version / remarks:

Version: 1984

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Tributyl phosphate

EC Number:

204-800-2

EC Name:

Tributyl phosphate

Cas Number:

126-73-8

Molecular formula:

C12H27O4P

IUPAC Name:

tributyl phosphate

Details on test material:

No further information is reported.

Sampling and analysis

Analytical monitoring:

yes

Test substrate

Vehicle:

no

Details on preparation and application of test substrate:

500 mg/L TnBP was ultrasonic dispersed at 50 °C and sequentially dissolved with distilled water, 10 mL different concentrations of 500, 50 and 5 mg/L TnBP were added to 165 mL distilled water and then thoroughly mixed with the artificial soil to obtain desired TnBP concentration (0, 0.1, 1, and 10 mg/kg (dry
soil)). Different concentrations of TnBP (0, 0.1, 1, and 10 mg/kg (dry soil)) were prepared with distilled water and were thoroughly mixed with the artificial soil.

Test organisms

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

Earthworms cultured outdoor were obtained from a local farming factory (Jurong, China) and acclimatized at 20 ± 1 °C for at least one week prior to avoid interference caused by external environment and help earthworms adapt to the exposed environment. After acclimatization, healthy adult earthworms with clear clitellum (weighing approximately 500−600 mg) were chosen for artificial soil test.

Study design

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

yes

Total exposure duration:

14 d

Test conditions

Test temperature:

20 ± 1 °C

Moisture:

final soil moisture 35 % (w/w)

Details on test conditions:

Artificial soil tests were conducted in 1 L clear glass bottles with 500 g dry artificial soil (final soil moisture 35 % (w/w)) following the OECD guidelines (OECD, 1984).
After the prepared soil had stabilized at 20 ± 1 °C for one week, 10 earthworms (acclimatized to artificial soil for 24 h) were placed in each container and kept in an incubator at 20 ± 1 °C in the dark for 14 days. Each concentration consisted of six bottles/replicates.

Nominal and measured concentrations:

nominal: 0, 0.1, 1, and 10 mg/kg (dry soil)

Results and discussion

Details on results:

A LC50 value was not reported.

Any other information on results incl. tables

The weight of earthworms increased in all treatments with time and multi way ANOVA identified a significant difference between biomass and time at the 0.05 level; however, no significant dose-related difference were observed between treatments.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

The mortality in the controls did not exceed 10% at the end of either test.

Conclusions:

The artificial soil test showed no significant dose-related difference in mortality (lower than 5%) for the exposure of E. fetida with tributyl phosphate (nominal concentration: 0, 0.1, 1, and 10 mg/kg (dry soil)) over a period of 14 days.

Executive summary:

Artificial soil tests similar to OECD TG 207 suggested that the acute toxicity of tributyl phosphate (TnBP) towards earthworm Eisenia fetida is quite low since no mortality occurred and a steady increase of biomass was observed.

The overall objective of the present study was to investigate the TnBP induced intestinal toxicity mechanism on earthworm Eisenia fetida as well as the potential role of gut bacteria on host’s health. TnBP was found to have high bioconcentrations in earthworm intestinal tract. Digestive tract degradation and digestive enzyme activities disruption associated with nutrients absorption were noticed. Using multi-omics approaches, detailed intestinal toxic mechanism of earthworms under TnBP exposure was provided.
Tight junctions between small intestinal epithelial cells and osmotic equilibrium were destroyed under 10 mg/kg TnBP, leading to nutrient absorption disturbance. To satisfy the excessive energy requirements induced by TnBP, amino acids gluconeogenesis and protein degradation were detected. Moreover, TnBP significantly decreased the diversity of gut microbiota and changed their structure and function involved in hosts’ health and nutrients supply.

The long-term toxicity data was not generated according to the specifications set out in OECD TG222.