4-amino-5-hydroxynaphthalene-1,7-disulphonic acid

Toxicity to aquatic algae and cyanobacteria

Description of key information

The effect of test item disodium 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid, CAS No. 130-23-4 was studied [UERL Study Report, Sustainability Support Services (Europe) AB (Report no. 130-23-4/01/2016/AT), 2016] on the growth of fresh water green alga Chlorella vulgaris. The study was conducted following OECD guideline 201- Alga, growth inhibition test. The test concentration chosen for the study were 6.25mg/l, 12.5mg/l, 25mg/l, 50mg/l,100mg/l and 200mg/l. The test concentrations were prepared using stock solution of the test item using mineral media. The green alga was exposed to the test concentration for a period of 72 hours to observe average specific growth rate and % growth inhibition under the effect of the test item. EC50 calculated graphically through probit analysis was observed to be >200mg/l.

Key value for chemical safety assessment

EC50 for freshwater algae:

200 mg/L

Additional information

Various studies for the target chemical 4-Amino-5-hydroxynaphthalene-1,7-disulphonic acid including the predicted data and its read across substance were reviewed to summarize the following information:

 

The effect of test item disodium 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid, CAS No. 130-23-4 was studied [UERL Study Report, Sustainability Support Services (Europe) AB (Report no. 130-23-4/01/2016/AT), 2016] on the growth of fresh water green alga Chlorella vulgaris. The study was conducted following OECD guideline 201- Alga, growth inhibition test. The test concentration chosen for the study were 6.25mg/l, 12.5mg/l, 25mg/l, 50mg/l,100mg/l and 200mg/l. The test concentrations were prepared using stock solution of the test item using mineral media. The green alga was exposed to the test concentration for a period of 72 hours to observe average specific growth rate and % growth inhibition under the effect of the test item. EC50 calculated graphically through probit analysis was observed to be >200mg/l.

 

 

72 hrs aquatic toxicity study (Danish (Q)SAR Database, 2016) was conducted to assess toxic effects of the test compound 4-Amino-5-hydroxynaphthalene-1,7-disulphonic acid (CAS no 130-23-4) and the results were predicted. The study was based on the effects of the test compound on Pseudokirchneriella spp. in a static fresh water system. The predicted data suggests the effective concentration (EC50) for the test compound 4-Amino-5-hydroxynaphthalene-1,7-disulphonic acid (CAS no 130-23-4) was estimated to be 39583.34 mg/L on the basis of growth rate.

 

 

96 hrs aquatic toxicity study (EPI suite, 2016) was conducted to assess toxic effects of the test compound 4-Amino-5-hydroxynaphthalene-1,7-disulphonic acid (CAS no 130-23-4) and the results were predicted. The study was based on the effects of the test compound on green algae in a static fresh water system. The predicted data suggests the effective concentration (EC50) for the test compound 4-Amino-5-hydroxynaphthalene-1,7-disulphonic acid (CAS no 130-23-4) was estimated to be 111000 mg/L on the basis of growth rate.

 

 

Short term toxicity to Chlorella pyrenoidosa (green algae) study was carried out for 72 hrs (JU-CHANG HUANG and EARNEST F. GLOYNA, 1968)

Emerson strain of bacteria free, experimentally reproducible cultures of Chlorella pyrenoidosa was used as a test organism. The procedure involve the use of test tubes in both the screening and final tests. These test tubes contained 15 ml of inorganic culture medium, a predetermined amount of test chemical and 5 ml of algal culture. The tubes were incubated for 72 hrs and chlorophyll content of the algal suspensions was measured every 24 hrs. For chlorophyll measurement, the chlorophyll pigment was extracted with hot methanol in two separate extractions. An algal suspension, 2.5 ml, was removed from the test tube, centrifuged, washed with distilled water, and recentrifuged in preparation of chlorophyll analysis. After discarding the supernatant, the deposited cell material was coagulated by placing the cells in a boiling water bath for about 40 sec. About 2.5 ml of methanol were used in each extraction. Finally, the chlorophyll solution was diluted to a total volume of 10 ml with an acetone-water mixture (80 per cent by volume). A Beckman Spectrophotometer, Model DB, was used to measure the chlorophyll content. For this a wavelength of 652 m/z was used because different proportions of chlorophyll a and b least affect the results at this wavelength. Control tubes containing no test chemical was also used in the experiment. Knop's solution, including the Hutner-EDTA microelement addition, was used as the culture medium. pH of culture medium was adjusted to 7.0 using KOH before use. The test organism was maintained under steady-state conditions, provided a chlorophyll content of 38 mg/l. Environmental control was rigidly maintained. The temp. of water bath was 25 ± 1°C. The test apparatus consisted of a constant-temperature water bath, a light source containing four 200W fluorescent lamps with attached aluminum reflectors, a gas manifold to supply an air-CO2 mixture to each test tube, and a rack to hold the test tubes. A stream of 5 % CO2 in air gas mixture was supplied to culture medium in order to provide the inorganic carbon source and also to keep the algal ceils in suspension.

 

Based on destruction of chlorophyll of test organism by chemical Amino-1-phenol-4-sulfonic acid, the LOEC value was found to be1500 mg/l and as no toxic effect at 1000 mg/l was observed, the NOEC value was found to be 1000 mg/l.

 

 

 

Short term toxicityto Chlorella pyrenoidosa (green algae) study was carried out for 72 hrs (JU-CHANG HUANG and EARNEST F. GLOYNA, 1967).

 

Emerson strain of bacteria free, experimentally reproducible cultures of Chlorella pyrenoidosa was used as a test organism. An Emerson strain of bacteria-free, experimentally reproducible cultures of Chlorella pyrenoidosa was obtained from Dr.Jack E. Myers, Professor of Zoology and Botany and Director, Laboratory of Algal Physiology, The University of Texas. Five conc. levels of test chemical were used for the tests (100, 500, 1000, 1500 and 2000 mg/l, respectively). A test tubes was used in the screening and final tests. These test tubes contained 15 ml of inorganic culture medium, a predetermined amount of test chemical and 5 ml of algal culture. The tubes were incubated for 72 hrs and chlorophyll content of the algal suspensions was measured every 24 hrs. Control tubes containing no test chemical in the culture medium was also used in the experiment. Environmental control was rigidly maintained. The temp. of water bath was 25 ± 1°C. The special toxicity test device consisted of an aquarium complete with a light source, a gas manifold and an apparatus for holding the test tubes. In this test device, algal cultures were kept under a rigid environmental control. A stream of 5 % CO2 in air gas mixture was supplied to culture medium in order to provide the inorganic carbon source and also to keep the algal ceils in suspension. Screening tests were performed to establish the threshold toxic concentration as well as completely algicidic one. Knop's solution, including the Hutner-EDTA microelement addition, was used as the culture medium. pH of culture medium was adjusted to 7.0 using KOH before use. Kimble Product of plain culture tubes, Series 45060, was used as the test tube. These test tubes have the size of 19 x 150 mm with a volume of 25 mI. The initial algal cell density was1.0 gm/l dry weight or equivalent to 3.8 cm/ml packed cell volume and chlorophyll content was 38 mg/l. The chlorophyll pigment was extracted with hot methanol from a 2.5ml algal suspension which was pipetted out of the test tube. The algal cells were centrifuged out of the culture medium, washed with distilled water and then centrifuged again. The supernatant was discarded and the remaining packed cell material was coagulated in a boiling water bath for a period of about 30 to 45 seconds depending on the amount of cells. Thereafter, the chlorophyll was extracted twice by using hot methanol. The extracted chlorophyll solution was then dissolved in 80 percent by volume acetone-water mixture to make a final total volume of 10 ml. The chlorophyll content was then analyzed under the spectrophotometer. Content of all extracted chlorophylls which were dissolved in 10mlof 80 percent acetone-water mixture could be determined by measuring the optical density (O.D.) at a wavelength of 652 mn. This wavelength was optimum because various proportions of chlorophylls a and b would least affect the result. A Beckman Spectrophotometer, Model DB, was used for all chlorophyll analysis. This spectrophotometer is a double beam instrument for making transmittance and absorbance measurements in the 205 to 770mn wavelength range.

 

Based on the decrease in chlorophyll content of test organism by test chemical Amino-1-phenol-4-sulfonic acid, the LOEC value was found to be 2000 mg/l and as no toxic effect at 1000 mg/l was observed, the NOEC value was found to be 1000 mg/l.

 

 

On the basis of the above resultsof various studies for target chemical and its read across substance, it can be concluded that the substance can be considered as non- hazardous to aquatic organisms.