Registration Dossier

Administrative data

Endpoint:
monitoring data
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
other: grey literature

Data source

Reference
Reference Type:
grey literature
Title:
No title available
Author:
United Nations Environment Programme
Year:
1995
Bibliographic source:
UNEP Environment library No 14, Nairobi, Kenya

Materials and methods

Principles of method if other than guideline:
No data
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Sodium hydroxide
EC Number:
215-185-5
EC Name:
Sodium hydroxide
Cas Number:
1310-73-2
Molecular formula:
HNaO
IUPAC Name:
sodium hydroxide

Results and discussion

Any other information on results incl. tables

NaOH is present in the environment as sodium and hydroxyl ions. Both sodium and hydroxyl ions have a wide natural occurrence. In a global water monitoring program (UNEP, 1995)  pH and sodium concentrations were two of the parameters that were monitored in many lakes and rivers. The most important freshwater aquatic ecosystems of the world revealed average annual pH values between 6.5 and 8.3 but lower and higher values have been measured in other aquatic ecosystems. In aquatic ecosystems with dissolved organic acids a pH of less than 4.0 has been measured, while in waters with a high chlorophyll content the bicarbonate assimilation can result in pH values of higher than 9.0 at midday. The global mean pH value is 7.7. Within this range the bicarbonate ion is the most common carbonate species found in natural waters. In streams (100 km2) bicarbonate concentrations range from 0 to 350 mg/l, while in major rivers (> 100,000 km2) the concentration ranges from 10 to 170 mg/l. Sodium concentrations in lakes and rivers display strong variability and orginate from natural weathering of rock, from atmospheric transport of oceanic inputs and from a wide variety of anthropogenic sources. Sodium concentrations in European rivers range between 1.2 and 574 mg/l.

Applicant's summary and conclusion