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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

Administrative data

Endpoint:
toxicity to soil macroorganisms except arthropods: long-term
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Published public domain study

Data source

Reference
Reference Type:
publication
Title:
Long-term effects of nitrogenous fertilizers on grassland earthworms (Oligochaeta: Lumricidae): Their relation to soil acidification
Author:
Wei-Chun Ma., Brussaard, L. & de Ridder, J.A.
Year:
1990
Bibliographic source:
Agriculture, Ecosystems and Environment 30(1-2): 71-80

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Long term fertiliser exposure in earthworms
GLP compliance:
no

Test material

Constituent 1
Reference substance name:
Urea
EC Number:
200-315-5
EC Name:
Urea
Cas Number:
57-13-6
IUPAC Name:
urea
Details on test material:
Organic coated urea (coating based on soybean oil), granular form fertiliser; 'Osmocote', obtained from Sierra Chemical Europe.
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Sampling and analysis

Analytical monitoring:
not specified
Details on sampling:
No information available

Test substrate

Vehicle:
not specified
Details on preparation and application of test substrate:
Fertiliser

Test organisms

Test organisms (species):
other: Oligochaeta and Lumbricidae
Animal group:
other: grassland worm
Details on test organisms:
Grassland worms; Oligochaeta and Lumbricidae

Study design

Study type:
field study
Substrate type:
natural soil
Limit test:
no
Total exposure duration:
1 040 wk
Remarks:
20 years
Post exposure observation period:
Not examined

Test conditions

Test temperature:
No information available; field study
pH:
No information available
Moisture:
No information available
Details on test conditions:
The study began in 1965. Uncultivated turf grass on sandy loam soil, situated near the Institute of Soil Fertility, Haren, The Netherlands. Organic matter content 6.2 - 6.7%. The site was divided into plots according to a randomised complete block design with 2 replications of each treatment. The plots were mowed once or twice a week during the growth seasons and harrowed once a year at the end of the winter period. Lime was added in 1983 to stabilise the pH of the soil.
The fertiliser was applied twice a year, in mid March and at the beginning of August.
Earthworms were sampled in October/November 1985 (at the end of the 20 year exposure period) by hand-sorting of excavated soil blocks 30 cm² x 15 cm deep, followed by extraction from deeper layers using formalin. The earthworms were fixed and kept in 70% ethanol plus 5% formalin. The biomass of preserved worms was detemined.
Nominal and measured concentrations:
Annual rate of 60, 120, and 180 kg N/ha
Reference substance (positive control):
no

Results and discussion

Effect concentrations
Dose descriptor:
other: Urea fertiliser reduced earthworm numbers and biomass and lowered pH.
Details on results:
Application of nitrogenous fertilisers to grassland for long periods may have a deleterious effect on earthworms in the absence of liming.
Results with reference substance (positive control):
Not examined
Reported statistics and error estimates:
ANOVA on log transformed data. Differences between means were assessed with the method of LSD.

Any other information on results incl. tables

Urea fertiliser reduced earthworm numbers and biomass and lowered pH.

Applicant's summary and conclusion

Validity criteria fulfilled:
not applicable
Conclusions:
Application of nitrogenous fertilisers to grassland for long periods may have a deleterious effect on earthworms in the absence of liming.
Executive summary:

Effects of long term use of urea fertiliser at 60, 120 and 180 kg N/ha/year was assessed on lumbricid earthworms in uncultivated turfgrass on loamy sand soil. The test sites were treated twice yearly for 20 years. Urea fertiliser reduced earthworm numbers and biomass and lowered pH. It was concluded that application of nitrogenous fertilisers for long periods may have a deleterious effect on earthworms in the absence of liming.

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