Tetrasodium ethylenediaminetetraacetate

Monitoring data

Administrative data

Endpoint:

monitoring data

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

supporting study

Study period:

May - June 1996

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2002

Report date:

2000

Materials and methods

Principles of method if other than guideline:

Several separate research projects have been carried out to evaluate the environmental fate and effects of the chelating agents used In the pulp and paper industries. The behavior of EDTA in environmental conditions, in the recipient area of a paper mill is presented.

GLP compliance:

not specified

Type of measurement:

background concentration

Media:

surface water

Test material

Test material information

Constituent 1

Reference substance name:

Edetic acid

EC Number:

200-449-4

EC Name:

Edetic acid

Cas Number:

60-00-4

Molecular formula:

C10 H16 N2 O8

IUPAC Name:

2,2',2'',2'''-(ethane-1,2-diyldinitrilo)tetraacetic acid

Test material form:

solid

Results and discussion

Concentration

Concentration 1

Key result

Country:

Finland

Location:

recipient area of paper mill

Substance or metabolite:

substance

Conc.:

1 - 88 µg/L

Remarks on result:

other: natural water samples in May 1996.

Concentration 2

Key result

Country:

Finland

Location:

recipient area of paper mill

Substance or metabolite:

substance

Conc.:

110 - 140 µg/L

Remarks on result:

other: pore-water of sediment samples, taken 1 km downstream of the discharge tube.

Any other information on results incl. tables

Overview:

The fate of chelating agents in the pulp and paper mill recipients has recently been studied. Depending on the sampling site, depth, and the time of the year concentrations of 1-710 ug/L (EDTA) have been found. In Sweden, concentrations of up to735 ug/L for EDTA have been found in the samples taken in the winter when the sampling sites were covered by ice and snow.

Once discharged in the aquatic environment the metal complexes of EDTA are degraded either by ultraviolet light or microorganisms or they may be absorbed in the sediment. Photochemically degraded EDTA particularly their Fe(lll) complexes, comprise the vast majority of all EDTA which disappears from river, lake or sea water. The photochemical degradation of chelating agents reported theoretical half lifetimes under optimized conditions of 11 and 8 minutes for EDTA. However, the true environmental half lifetime is likely longer. The primary degradation products have been identified. They consist of aminopolycarboxylic acid structures obtained from EDTA by cleavage of one acetic acid group.

Paper Mill, May 1996:

The lowest concentrations (1-2 ug/L) were detected at the sampling sites located from 23 to 34 km upstream from the discharge tube. The concentrations of EDTA were also very low (2 ug/L) at the sampling site located 52 km downstream from the tube. The highest concentration (88 ug/L) was determined at the sampling site closest to the discharge place. It should be noted that the concentrations of EDTA measured in the samples taken from a depth of 8 m at a distance of 1 km from the tube were markedly higher than in those taken from a depth of 1 m. One explanation for this is the UV light-induced degradation of EDTA, but others such as the depth of the end of the discharge tube may also be worth considering. Since the concentration of EDTA in the treated effluent of this mill was in the range of 9-10 mg/L, dilution factors ranging from 100 to 10,000 were calculated.

Paper Mill, July 1996, pore-water:

The difference between the highest water and the highest sediment pore-water concentrations could be again explained by the effect of UV-light. The upper layer (<10 cm) of the sediment sample had the highest, and the bottom layer (30-40 cm) the lowest concentration of EDTA in the pore-water. This could at least partly be explained by the rate of settling, which in this case was estimated to be about 1 cm/a, This particular mill has used EDTA for the last 30-40 years, which could be seen in the concentrations of EDTA in the pore-water of the sediment samples. In natural environmental conditions the amount of EDTA absorbed in the sediment is very small, the highest in the case of this mill being 7 ug/kg in the upper layer (<10 cm) of the sediment sample.

Applicant's summary and conclusion

Executive summary:

The degradation of EDTA in environmental conditions was studied in a paper mill recipient. The highest concentrations were found in the sampling site closest to the discharge pipe, and the concentrations were also dependent on the sampling depth. The fraction of EDTA absorbed in the sediment and the concentrations in the pore-water of the sediment samples were also determined, Concentrations in the sediment pore-water were even higher than in the water samples taken from the same location. The difference can be explained by the effect of UV light. The amount of EDTA absorbed in the sediment was negligible.