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Environmental fate & pathways

Monitoring data

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Administrative data

Endpoint:
monitoring data
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Study period:
May - June 1996
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: study acceptable, but poorly summarized. Secondary source.

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

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
no data availble

Results and discussion

Concentrationopen allclose all
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.
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.