Reaction mass of tetramethylammonium hypochlorite and tetramethylammonium chloride

Short-term toxicity to fish

Description of key information

The target substance is a multi-constituent substance analogue to the inorganic bleaching agents. The intrinsic ecotoxicological properties of the target substance are caused by the available chlorine concentrations in water solutions. Based on the mechanistic reasoning, the read-across data from the literature for chlorine compounds measured as total residual chlorine in water solutions was justified to be used to evaluate the acute toxicity of the target substance to fresh water and marine water fish. Based on the publicly available literature, the 96-h LC50-values indicating the highest toxicity response were selected as a key value for CSA.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.09 mg/L

Marine water fish

Marine water fish

Effect concentration:

0.032 mg/L

Additional information

The target substance is a multi-constituent substance analogue to the commonly known inorganic bleaching agents such as chlorine and chloride and hypochlorite solutions. The target substance is a reaction mass from blending of two components (benzotriazole solid and 25 % tetramethylammonium hydroxide water solution) followed by reaction with chlorine gas. It contains tetramethylammonium hypochlorite and tetramethylammonium chloride as the main reaction products. The main component of this reaction mass is tetramethylammonium hypochlorite which is strong oxidiser and comparable to other chlorinated bleaching agents. The intrinsic ecotoxicological properties of this substance are related to the available chlorine concentration, which describes the oxidising power of a chlorine containing solution as if all chlorine species present were available as Cl2. The available chlorine of the target substance (Cl2-%) ranges between ca. 7.7― 8.6 %.

Based on the mechanistic reasoning, the read-across data from the above analogue inorganic bleaching agents were used to evaluate the acute toxicity to fish (see read-across justification in IUCLID section 13). Since the data collected from the literature already presents clear acute toxicity to fish, testing was considered unjustified. By using the read-across data, the unnecessary animal testing could be avoided. In addition, the new GLP-studies which have been conducted for other aquatic species (Algae and Daphnia) present similar toxicity levels than the studies described below. Therefore, there is enough ecotoxicity data to conclude the C&L for the target substance.

 

Toxicity in freshwater

 

Brooks & Seegert (1977) investigated the effects of single (30 min) and multiple (5 min exposure at 3 hours interval) exposures to sodium hypochlorite in lake water with and without the addition of a thermal stress on two species of fish - Perca flavescens and Salmo gairdneri (juveniles). A single 30 minute dose was found to be more toxic than the triple exposure of 5 minutes. Generally, S. gairdneri was more sensitive than Perca flavescens; after 24h recovery, the LC50 was 990 μg/l. With the addition of a thermal stress, the median lethal concentration lowered to 430 μg/l.

In the study by Bellanca & Bailey (1977), the chlorine toxicity to ocean spot was investigated beside with field studies to investigate effects of chlorinated effluents on aquatic ecosystem in the lower James River. The laboratory-scale study on chlorine toxicity to ocean spot (Leiostomus xanthurus) was conducted using a continuous flow serial diluter (simplified dosing apparatus for fish toxicology studies by Mount D.I and Brungs W.A (1967), Water Res. 1, 21. 1967). Chlorine was fed as a stock solution to the test system and measured as total residual chlorine by amperometric titration. The toxicity levels (TL) were determined for 24-hour and 96-hour exposure. The 24-h LC50 was 0.14 mg/l and the 96 -h LC50 was 0.09 mg/l. No fish survived concentrations of 0.16 mg/l or more for 96 hours. No mortality was observed at concentrations of 0.04 mg/l or less.

 

The following symptoms were observed during the study: Test fish exhibited increased movement and swimming activity, followed by gulping at the surface. Surface activity was increased with fish pushing their mouths and heads out of the water and coughing or spitting water. Circular, erratic swimming began with a gradual loss of equilibrium which frequently led to an upside-down resting state. Final reactions involved violent surges of undirected movement, with fish sometimes leaving the water; convulsions often occurred. - Mortality of control: no mortality in the controls.

 

In the study by Curtis & Ward (1981), the 96-h freshwater LC50 (mortality) of fathead minnow (Pimephales promelas) to sodium hypochlorite solution was determined using static test system and measured concentrations at controlled temperature. The study was non-GLP study and but similar to the EPA methods (acute fish toxicity test). The 96-h LC50 was 5.9 mg/l with CI of 4.8-8 mg/l.

 

These studies were used in a weight of evidence approach to evaluate the acute toxicity of the target substance but it was not considered as reliable enough to be used as a key study since the study was not well reported. However, the findings of these studies can be used to evaluate the toxicity of the target substance which contains analogue components to inorganic sodium hypochlorite bleaching agents, and in which the available chlorine is also the driving force for the toxicity effects and the hazard assessment. Based on these studies the 96-h LC50-value indicating the highest toxicity response was selected as a key value for CSA.

Toxicity in salt water

 

In the study by Thatcher (1978), the 96-h acute toxicity to marine water fish species was determined by using a flow-through type of testing. The exposure concentrations to different loadings of available chlorine (measured as total residual oxidant = TRO) were prepared by mixing a commercial product (Clorox) with unfiltered sea water. This product contained 90.42 % of water, 5.25 % of sodium hypochlorite, 4.12 % of sodium chloride, 0.20 % of sodium carbonate and 0.01 % of sodium hydroxide. The LC50 -values ranged between 0.032 mg TRO/L to 0.167 mg TRO/L the coho salmon (Oncorhynchus kisutch) being the most sensitive and the threespine stickleback (Gasterosteous aculeatus) being the least sensitive species.

 

In the study by Capuzzo et al. (1977), two types of continuous-flow systems with aeration at ambient temperature were used to determine the 100 % mortality and behaviour aberrations of three salt water fish species: (Pseudopleuronectes americanus), the winter flounder, (Stenotomus versicolor), the common scup, and (Fundulus heteroclitus), the killifish to free chlorine and chloramine as toxicant during 48 h exposure. The toxicants were introduced to unfiltered sea water. The concentrations were measured as total residual chlorine levels. The 100 % mortality was observed very rapidly within 1-6 hours after exposure. The IC100 % for winter flounder and scup was observed with exposure to 0.55 and 0.65 mg/l residual chlorine applied as chlorine and 2.55 mg/l and 3.10 mg/l residual chlorine applied as chloramine, respectively. The IC 100 % for killifish was observed with exposure to 0.65 mg/l as free chlorine and 1.20 mg/l as chloramine.

 

Based on the study results by Capuzzo et al., the behavioural aberrations -distended gills and erratic swimming behaviour - were noted at concentrations approaching the lethal levels of free chlorine and chloramine (0.2 to 0.5 mg/l as total residual chlorine applied as free chlorine and 1.5 to 2.2 mg/l applied as chloramine). In addition, only slight decrease in lower oxygen uptake of killifish was observed with exposure to 2 mg/l applied chloramine but more significant decreases were observed with exposure to 2 mg/l applied as free chlorine and 4 mg/l applied as chloramine.

 

There was not enough information on the test conditions and the methodology in these publications to consider any of these studies as a key study for C&L purposes. However, based on the composition of the test materials the chlorine content and the composition is analogue to the target substance. Therefore, these studies were used as a read-across data for WoE approach to evaluate the acute toxicity to marine fish species. The findings of these studies can be used to evaluate the toxicity of the target substance in which the available chlorine is also the driving force for the toxicity effects and the hazard assessment. Based on these studies the 96-h LC50-value indicating the highest toxicity response was selected as a key value for CSA.