Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
no hazard identified

Marine water

Hazard assessment conclusion:
no hazard identified

STP

Hazard assessment conclusion:
no hazard identified

Sediment (freshwater)

Hazard assessment conclusion:
no hazard identified

Sediment (marine water)

Hazard assessment conclusion:
no hazard identified

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
no exposure of soil expected

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

Eco-toxicological information (hydrogen chloride and hydrochloric acid):

Endpoint data are based on on studies with hydrochloric acid. Hydrogen chloride (HCl) dissolved in water, also known as aqueous hydrogen chloride will immediately dissociate to become hydrochloric acid, with a pH dependent on the concentration. In as far as HCl does not react away with hydroxyl radicals, the hygroscopic gas will react with moisture in air, soil or biological media to form hydrochloric acid. Accidently escaped gas will thus mostly precipitate as diluted hydrochloric acid to water or soil. Therefore, the studies based on hydrochloric acid are believed to be equally valid for eco-toxicological hazard identification of HCl gas. Quantitative assessments are based on the actual amount/ concentration of HCl or, where appropriate, on the worst-case assumption that HCl gas will be absorbed in water or biological media to the highest possible concentration of hydrochloric acid.  

The effect are related to pH effects only, the aquatic environment is the only compartment that might be exposed to the substance. The PNECs are derived from the EU legislation on pH range (Council Directive (78/659/EEC)

Environment / Ecotoxicological information

According to the OECD SIDS 2002 Hydrogen chloride SIAR:

Hydrogen chloride is readily dissociated in water into hydrated protons and chloride ion.

The hazard of hydrogen chloride (in aqueous systems: hydrochloric acid, consisting fully of dissociated chloride and hydronium ions) for the environment is caused by the hydronium ion, hence a pH effect as outlined in chapter 4.1.1.1, because chloride toxicity values to aquatic organisms are much higher (most toxicity values are greater than 100 mg/L), which are derived from some chlorides such as sodium chloride, calcium chloride, potassium chloride (OECD SIDS on Hydrogen Chloride, 2002).

For this reason the effect of hydrochloric acid on the organisms depends on the buffer capacity of the aquatic ecosystem. Also the variation in acute toxicity for aquatic organisms can be explained for a significant extent by the variation in buffer capacity of the test medium..

It is not considered useful to calculate a PNEC for hydrochloric acid because factors such as the buffer capacity, the

natural pH and the fluctuation of the pH are very specific for a certain ecosystem.

There is a possibility that the emission of hydrochloric acid could locally decrease the pH in the aquatic

environment. Normally, the pH of effluents is measured very frequently to maintain the water quality. In addition to

that, water quality including the range of pH could be managed properly to prevent adverse effects on the aquatic

environment based on the criteria of the pH in rivers and lakes.

Therefore, a significant decrease of the pH of the receiving water is not expected. Generally the changes in pH of the receiving water should stay within the natural range of the pH, and for this reason, adverse effects on the aquatic environment are not expected due to

anthropogenic or naturally occurring hydrochloric acid.

Conclusion on classification

The substance could be classified as "acute aquatic toxicity category 1" due to the fact that the recalculated EC50 for Daphnids is < 1 mg/L in a standard OECD guideline medium, as it is the highest pH at which effects have been observed, which was 4.92 in the key study. To get to that pH level in low buffered natural waters (worst case), at least 10 mg/L HCl would be required, see OECD SIDS on Hydrogen Chloride, 2002, chapter 2.2.2 with Table 2-1 (based on Groot de W.A. and Dijk van N.R.M. 2002. Addition of hydrochloric acid to a solution with sodium bicarbonate to a fixed pH. Solvay Pharmaceuticals; Study No. A SOL.S.027). This qualifies for “acute aquatic toxicity category 3” according to GHS criteria. There is however no classification for aquatic toxicity required under the CLP regulation.

It is not considered useful to calculate a PNEC for hydrochloric acid because factors such as the buffer capacity, the natural pH and the fluctuation of the pH are very specific for a certain ecosystem.

Moreover HCl is not classified for the environmental compartment based on its dissociation in the environment, lack of bioaccumulation and lack of adsorption to particulate matter or surfaces.