Diboron trioxide

Long-term toxicity to fish

Administrative data

Endpoint:

fish short-term toxicity test on embryo and sac-fry stages

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well performed study

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1981

Materials and methods

Principles of method if other than guideline:

no guideline was reported

GLP compliance:

no

Test material

Reference

Name:

Unnamed

Type:

Constituent

Details on test material:

The boron compounds used for testing were obtained from the Fisher Scientific Company. Boric acid (H3BO3) was certified ACS grade.

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Source: Gravid fish and amphibians were obtained from State and Federal hatcheries at Frankfort, Kentucky, Erwin, Tennessee
- Boron treatment was initiated subsequent to fertilization


METHOD FOR PREPARATION AND COLLECTION OF FERTILIZED EGGS
- Method of collection of fertilised eggs: Trout eggs and sperm were collected for test purposes by artificial spawning and milking, using methods of Leitritz. Fertilization was accomplished by mixing sperm and eggs for 15 minutes immediately prior to the onset of boron exposure.

Study design

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

28 d

Test conditions

Hardness:

197 mg/L

Test temperature:

13.2 °C

pH:

7.4

Dissolved oxygen:

9.8 mg/L

Nominal and measured concentrations:

Nominal concentrations : 0.01, 0.10, 1.00, 10.00, 25.0, 50.0, 100.00, 200.00, 300.00, 400.0, 500.0 mg B/L
Measured concentrations: 0.008, 0.1, 1.26, 10.19, 24.98, 49.36, 100.0, 196.1, 383.3, 482.2 mg B/L

Details on test conditions:

TEST SYSTEM
Fish eggs were cultured through 4 days posthatching in Pyrex chambers, through which test water was perfused at prescribed flow rates. The toxicant was administered to a mixing chamber situated ahead of each culture dish, using graduated flow from a syringe pump. Synthetic culture water was delivered to the mixing chamber by regulated flow from a peristaltic pump. Flow rates from both syringe and peristaltic pumps were monitored by liquid flow meters. Flow rate was set at 200 ml /hr for 300 ml test chambers. Syringe and peristaltic pumps were provided with calibrated, continuously variable speed controls. The concentration of toxicant delivered to the mixing chamber was regulated by adjusting the mixing ratio from the pumping units and/or by varying the concentration of toxicant delivered from the syringe pump. Solutions from the two channels were mixed with a Teflon-coated magnetic stirring bar, and delivered to the culture chamber under positive pressure.
The system was operated using Brinkmann (model 131900) and Gilson (model HP8) multichannel peristaltic pumps and Sage syringe pumps (model 355)). The latter was fitted with a modified syringe holder, and operated using 10 ml double-ground, glass syringes. Syringes were selected for equal stroke volume, and peristaltic pump channels were fitted with tubing of matched diameters.
For test concentrations of 10 ppm or more, boron compounds generally were added directly to the culture water in the peristaltic pump reservoir, eliminating the need for the syringe pump channel. In such instances, the toxicants remained stable at selected test concentrations for 24 hours or more in polyethylene containers, and important test parameters of culture water were not altered upon standing.
All aquatic bioassay cultures were maintained in walk-in environmental rooms. Culture water was given continuous aeration in the peristaltic pump reservoirs.



TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Culture water was prepared from distilled, double deionized water, having a conductivity of 0.25 umhos or less. Routine monitoring was conducted for background contaminants, including mercury, cadmium, lead and other trace metals. Reagent grade calcium, magnesium, sodium and potassium salts were added. The basic stock was prepared to give a water hardness level of 200 ppm (as CaCO3) and a pH of 7.5 - 8.0. Different levels of hardness were achieved by dilution of the basic culture water.
- Alkalinity: 65 mg/L
- Conductivity: 282 umhos
- Intervals of water quality measurement: daily intervals


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

28 d

Dose descriptor:

LC10

Effect conc.:

5.1 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Basis for effect:

mortality

Remarks:

+ teratogenicity

Remarks on result:

other: confidence limits: 2.4 - 10.7 mg/L

Effect concentrations 2

Duration:

28 d

Dose descriptor:

LC10

Effect conc.:

31.4 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Basis for effect:

mortality

Remarks on result:

other: confidence limits: 10.0 - 98.5 mg/L

Reported statistics and error estimates:

Log probit analysis was used to statistically determine LC01 and LC50 values. The LC10/EC10 values have been recalculated with the log-logistic model using Toxicity Relationship Analysis Program, Version 1.21A