N,N'-diphenylguanidine monohydrochloride

Endpoint summary

Description of key information

Based on experimental results obtained with the read-across substance (CAS 102 -06 -7) the LC50 for short-term toxicity with fish is considered to be 4.2 mg/L for the test item.

Based on experimental data on short-term toxicity to Daphnia with the read-across substance (CAS 102 -06 -7), the 48h-LC50 of the test item was estimated to be 17 mg/L.

In a 72-h algal growth inhibition test with Raphidocelis subcapitata, the obtained results showed that the test item had inhibitory effects on the growth of the algae. The 72-h EC10 and EC50 for growth were determined to be 5.1 and 10.0 mg/L, respectively. The NOEC value based on growth rate and yield was determined to be 3.7 mg/L.

Based on experimental data on toxicity to microorganisms with the read-across substance (CAS 102 -06 -7), the EC50 of the test item is considered to be 147 mg/L.

Additional information

Short-term toxicity to fish (CAS 102 -06 -7)

The acute toxicity of the read-across substance to fathead minnows (Pimephales promelas) was assessed using the methods outlined by the Committee on Methods for Toxicity Tests with Aquatic Organisms. Water quality parameters of temperature, dissolved oxygen, pH and ammonia were measured throughout the test and were within acceptable limits. As a quality check, the fathead minnows were challenged with areferencecompound, Antimycin A. The observed 96 hour LC₅₀and 95% confidence limits (C.I.) were within the 95% confidence limits reported in the literature (2), indicating that the fish were in good condition. The results of the four day static fish toxicity study using fathead minnows are summarized below.

1,3-diphenylguanidine 96-hour LC50 = 4.2 mg/L (3.2 -5.6 mg/L)

Antimycin A96-hour LC50 = 0.000028 mg/L (0.000023 -0.000034 mg/L)

Also, the results indicated a 96 hour, no observed effect concentration of 1.8 mg/L.

Short-term toxicity to aquatic invertebrates (CAS 102 -06 -7)

In a study on the acute toxicity of the read-across substance to Daphnia a 48h-LC50 was estimated at 17 mg/L.The acute toxicity of DPG to Daphnia magna was assessed using the methods outlined by the Commitee on Methods for Toxicity Tests with Aquatic Organisms. Water quality parameters of temperature, dissolved oxygen and pH were measured at the termination of the test and were within acceptable limits. The results of the 48 hour static Daphnia magna toxicity study are summarized below.

1,3-diphenylguanidine 48-hour LC50 = 17 (14-21) mg/L. The no effect level observed for 1,3-diphenylguanidine was 5.6 mg/L after 48 hours.

Toxicity to algae

The effect of the test item on the growth of a unicellular green algal species Raphidocelis subcapitata was determined according to OECD 201, Regulation (EC) No. 226/2016 Method C.3 and EPA OPPTS 850.5400 and under GLP. The study was conducted under static conditions with an initial cell density of 1E4 cells/mL for a period of 72 hours. A concentration series of 0.55, 1.4, 3.7, 9.6 and 25 mg/L and control was performed. The measured concentrations of the test item at the start and at the end of the test were in the range of 84 - 101 % of the nominal concentration. The measured concentrations did not deviate more than 20 % from the nominal concentrations, therefore, the biological results were based on the nominal concentrations.The 72-h EC10, EC20, EC50 for growth were determined to be 5.1, 6.4 and 10.0 mg/L, respectively. The 72-h EC10, EC20, EC50 for yield were determined to be 2.6, 3.5 and 6.0 mg/L, respectively. The NOEC value based on growth rate and yield was determined to be 3.7 mg/L.The test item showed a significant toxic effect on the green unicellular algae.

Toxicity to microorganisms (CAS 102 -06 -7)

In an oxygen consumption test following OECD guideline 209, with unadapted activated sludge from a laboratory plant as inoculums, an EC50 -3 hours of 147 mg/L was estimated (79 -208 mg/L) for the read-across substance.