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Ecotoxicological information

Toxicity to terrestrial plants

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Administrative data

Endpoint:
toxicity to terrestrial plants: 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: Although the study was not carried out according to a guideline and GLP, it is well described and the result is considered acceptable.

Data source

Reference
Reference Type:
other: Note
Title:
Unnamed
Year:
2000

Materials and methods

Principles of method if other than guideline:
Acute and chronic effects of tetrachloroethylene (PER) on plants were studied in an experiment carried out between May 1999 and May 2000. Twelve plant species of different functional types (annual crops, wild herbaceous species, trees and bryophytes) were fumigated with PER up to six months in outdoor Open Top Chambers. The exposure levels used ranged from a minimum of 7 to a maximum of 2104 ug m-3, expressed as average seasonal concentrations.
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Commercially available liquid PER (Acros 99+%)

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
For measurement of PER in the air of the Open Top Chambers (OTCs) a sampling with absorption on Tenax was selected. The recovery after trapping for 1h 45 min, divided in 7 periods of 15 min in an experimental design consisting of two Tenax tubes connected in series. Thus, seven daily 15 min-aliquots can give insight in the average fumigation levels in one-week periods. Recovery of Tenax was tested under these conditions at 10, 20 and 30 °C in a climatic chamber. Seven 1 microliter-portions, containing each 50 ng (corresponds to 26 micrograms m-3), 150 ng, 500 ng, 1500 ng or 5000 ng of PER dissolved in diethylether were applied with 15 min intervals at an air flow of 128 ml min-1. The actual flow rate through the Tenax tubes in the Open Top Chambers throughout the experimental period was 128 ± 3 ml min-1.


Test substrate

Vehicle:
no
Details on preparation and application of test substrate:
Atmopsheric exposure

Test organisms

open allclose all
Species:
Phaseolus vulgaris
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
Bean - origin: seeded

Sown in 5-litre plastic pots filled with a clay-based nutrient-rich substrate and grown outdoors. After emergence plants were thinned to one plant per pot. The plants were fertilized fortnightly with a nutrient solution (for composition of Steiner-solution) and supplied with three drippers from the automatic watering system. The duration of water supply was 2 minutes per 12 hrs, but was extended to several minutes on hot, sunny days.
Species:
Brassica oleracea var. capitata
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
Cabbage - origin: seeded

Sown in 5-litre plastic pots filled with a clay-based nutrient-rich substrate and grown outdoors. After emergence plants were thinned to one plant per pot. The plants were fertilized fortnightly with a nutrient solution (for composition of Steiner-solution) and supplied with three drippers from the automatic watering system. The duration of water supply was 2 minutes per 12 hrs, but was extended to several minutes on hot, sunny days.
Species:
Triticum aestivum
Plant group:
Monocotyledonae (monocots)
Details on test organisms:
Wheat - origin: seeded

Sown in 5-litre plastic pots filled with a clay-based nutrient-rich substrate and grown outdoors. After emergence plants were thinned to one plant per pot. The plants were fertilized fortnightly with a nutrient solution (for composition of Steiner-solution) and supplied with three drippers from the automatic watering system. The duration of water supply was 2 minutes per 12 hrs, but was extended to several minutes on hot, sunny days.
Species:
other: Picea abies
Plant group:
Gymnospermae (conifers)
Details on test organisms:
Spruce - origin: nursery

Bought from a nursery in autumn 1998 and kept outdoors in 5-litre plastic containers filled with a peat/sand mixture (1:1). The trees were all three years old at the beginning of the experiment. For the experiments the individuals with similar size were chosen in spring 1999. The trees were fertilized
with slow-release nutrient pellets (Osmocote; N:P:K=13:13:13) and supplied with one dripper from the automatic watering system. The duration of water supply was 2 minutes per 12 hrs, but was extended to several minutes on hot, sunny days.
Species:
other: Pinus sylvestris
Plant group:
Monocotyledonae (monocots)
Details on test organisms:
Pine - origin: nursery

Pine trees were purchased from the nursery 6 weeks before the start of the experiment and planted in 20-litre plastic containers filled with a peat/sand mixture (1:1). The trees were all three years old at the beginning of the experiment. The age of blueberry plants was two years. For the experiments the individuals with similar size were chosen in spring 1999. The trees were fertilized with slow-release nutrient pellets (Osmocote; N:P:K=13:13:13) and supplied with one dripler from the automatic watering system. The duration of water supply was 2 minutes per 12 hrs, but was extended to several minutes on hot, sunny days.
Species:
other: Fagus sylvatica
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
Beech - origin: seeded

Bought from a nursery in autumn 1998 and kept outdoors in 5-litre plastic containers filled with a peat/sand mixture (1:1). The trees were all three years old at the beginning of the experiment. For the experiments the individuals with similar size were chosen in spring 1999. The trees were fertilized
with slow-release nutrient pellets (Osmocote; N:P:K=13:13:13) and supplied with one dripper from the automatic watering system. The duration of water supply was 2 minutes per 12 hrs, but was extended to several minutes on hot, sunny days.
Species:
other: Trifolium repens
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
White clover - origin: seeded

Sown in 5-litre plastic pots filled with a peat/vermiculite mixture (1:1) was used. After emergence plants were thinned to one plant per pot. Not fertilized during the experiment and supplied with one dripper from the automatic watering system. The duration of water supply was 2 minutes per 12 hrs, but was extended to several minutes on hot, sunny days.
Species:
other: Vaccinium myrtillus
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
Blueberry - origin: nursery

Bought from a nursery in autumn 1998 and kept outdoors in 5-litre plastic containers filled with a peat/sand mixture (1:1). The age of blueberry plants was two years. For the experiments the individuals with similar size were chosen in spring 1999. The plants were fertilized fortnightly with a nutrient solution (for composition of Steiner-solution) and supplied with three drippers from the automatic watering system. The duration of water supply was 2 minutes per 12 hrs, but was extended to several minutes on hot, sunny days.
Species:
other: Molinia caerulea
Plant group:
Monocotyledonae (monocots)
Details on test organisms:
Purple Moorgrass - origin: clones

Plants of Purple Moorgrass were propagated in April 1999 from a clone originating from a maternal plant collected in a fen-meadow close to Wageningen and cultivated on a nutrient poor sand-peat mixture. Not fertilized during the experiment and supplied with one dripper from the automatic watering system. The duration of water supply was 2 minutes per 12 hrs, but was extended to several minutes on hot, sunny days.
Species:
other: Polytrichum formosum
Plant group:
Bryophyta or Hepatophyta (mosses or liverworths)
Details on test organisms:
Haircap Moss - origin: forest

Pillows of the moss, including the underlying humus-layer, were collected in a forest nearby. Seedlings of higher plants and pieces of debris were removed from these and pillows were hence cut into pieces. These were put into 350 ml pots, which were placed into white 3L pots filled with washed river sand. Not fertilized during the experiment and were manually sprayed with water every day.
Species:
other: Pleurozium schreberi
Plant group:
Bryophyta or Hepatophyta (mosses or liverworths)
Details on test organisms:
Schreber's Moss - origin: forest

Pillows of the moss, including the underlying humus-layer, were collected in a forest nearby. Seedlings of higher plants and pieces of debris were removed from these and pillows were hence cut into pieces. These were put into 350 ml pots, which were placed into white 3L pots filled with washed river sand. Not fertilized during the experiment and were manually sprayed with water every day.
Species:
other: Rhytidiadelphus squarrosus
Plant group:
Bryophyta or Hepatophyta (mosses or liverworths)
Details on test organisms:
Goose Neck Moss - origin: forest

Pillows of the moss, including the underlying humus-layer, were collected in a forest nearby. Seedlings of higher plants and pieces of debris were removed from these and pillows were hence cut into pieces. These were put into 350 ml pots, which were placed into white 3L pots filled with washed river sand. Not fertilized during the experiment and were manually sprayed with water every day.

Study design

Test type:
other: atmpospehric exposure
Study type:
semi-field study
Substrate type:
other: substrate depending on species tested
Limit test:
no
Total exposure duration:
1.5 mo
Remarks:
Bean, clover: 31/05 – 14/07*; wheat: 10/05 – 28/07; cabbage: 10/05 – 03/08; spruce, pine, beech, blueberry: 10/05 – 08/11; purple moorgrass: 10/05- 02/09; mosses: 04/06 12/10 * 2nd exp. started on 19/07 and ended on 19/08 for bean and 12/10 for clover
Post exposure observation period:
Some plant assessments were extended to the period following the fumigation experiments in order to assess long-term vitality of plants following exposure to PER. These assessments included:
• After the fumigation period: post-exposure growth of mosses (% cover of moss-pillow);
• Spring 2000: bud-break in woody species (timing of bud-break, number of open buds).

Test conditions

Test temperature:
Experiment 1: 31 May-14 July: 15.8 ºC (average)
Experiment 2: 19 July-19 Aug: 18.1 ºC (average)
pH:
Not applicable
Moisture:
Not applicable
Details on test conditions:
In spring 1999 bean, wheat and kale were sown in 5-litre plastic pots filled with a clay-based nutrient-rich substrate and grown outdoors. For clover a peat/vermiculite mixture (1:1) was used. After emergence plants were thinned to one plant per pot. Spruce, beech and blueberry plants were bought in a nursery in autumn 1998 and kept outdoors in 5-litre plastic containers filled with a peat/sand mixture (1:1). Pine trees were purchased from the nursery 6 weeks before the start of the experiment and planted in 20-litre plastic containers filled with a peat/sand mixture (1:1). Pine, spruce and beech trees were all three years old at the beginning of the experiment. The age of blueberry plants was two years.
For the experiments the individuals with similar size were chosen in spring 1999. Plants of Purple Moorgrass were propagated in April 1999 from a clone originating from a maternal plant collected in a fen-meadow close to Wageningen and cultivated on a nutrient poor sand-peat mixture.
Pillows of the three moss species, including the underlying humus-layer, were collected in a forest nearby. Seedlings of higher plants and pieces of debris were removed from these and pillows were hence cut into pieces. These were put into 350 ml pots, which were placed into white 3L pots filled with washed river sand.

Six individuals of each species were used at each exposure level. Plants were grown in pots and arranged in the chambers so the trees did not overshadow the crop plants. Pots were rearranged at random in the chambers once a month. After the end of the exposures, the trees and the mosses were moved to a wind-sheltered location and monitored over the winter for any carry-over effects.

The polyacrylate sheets from which the chambers are made allow 85% of the photosynthetically active light to pass. Air is blown continuously into the chambers through a perforated floor. In this study, the ambient air was filtered through charcoal, then a stream of nitrogen containing the tetrachloroethylene was added to the air stream before blowing into the chambers.
Nominal and measured concentrations:
Nominal: 3145, 983, 307, 96, 30, 0 microgram m-3

Bean (1st exp.) 31 May-14 July 7 1958 708 288 109 82 11 microgram m-3
SD 415 133 69 42 56 15 microgram m-3
Clover (1st exp.) 31 May-14 July 7 1958 708 288 109 82 11 microgram m-3
SD 415 133 69 42 56 15 microgram m-3
Wheat 10 May-28 July 11 1966 747 249 98 78 10 microgram m-3
SD 408 154 81 37 46 12 microgram m-3
Kale 10 May-03 Aug 12 1955 758 244 94 86 10 microgram m-3
SD 390 152 79 38 51 11 microgram m-3
Bean (2nd exp.) 19 July-19 Aug 4 2056 979 218 82 132 13 6 microgram m-3
SD 315 144 22 36 26 8 6 microgram m-3
Moor Grass 10 May-02 Sep 14 2029 855 242 102 96 10 microgram m-3
SD 369 219 68 37 47 10 microgram m-3
Clover (2nd exp.) 19 July-12 Oct 11 2179 1131 246 107 168 7 4 microgram m-3
SD 243 152 31 41 61 5 4 microgram m-3
Mosses 04 June-12 Oct 18 2101 984 261 109 143 9 microgram m-3
SD 336 252 53 41 70 9 microgram m-3
Blueberry 10 May-08 Nov 19 2104 1009 252 127 102 7 microgram m-3
SD 324 271 56 60 80 7 microgram m-3
Trees 10 May-08 Nov 25 2104 1009 252 127 102 7 microgram m-3
(=seasonal mean) SD 324 271 56 60 80 7 microgram m-3

Results and discussion

Effect concentrationsopen allclose all
Species:
Phaseolus vulgaris
Duration:
1.5 mo
Dose descriptor:
NOEC
Effect conc.:
46 other: ug/m3
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: Pod dry weight
Species:
Phaseolus vulgaris
Duration:
1 mo
Dose descriptor:
NOEC
Effect conc.:
>= 2 056 other: ug/m3
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: pod dry weight
Species:
Triticum aestivum
Duration:
3 mo
Dose descriptor:
NOEC
Effect conc.:
> 747 - < 1 966 other: ug/m3
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: ear dry weight
Species:
other: Brassica oleracea
Duration:
3 mo
Dose descriptor:
NOEC
Effect conc.:
>= 1 955 other: ug/m3
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: shoot dry weight
Species:
other: Picea abies
Duration:
6 mo
Dose descriptor:
NOEC
Effect conc.:
387 other: ug/m3
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: stem diameter
Species:
other: Pinus sylvestris
Duration:
6 mo
Dose descriptor:
NOEC
Effect conc.:
387 other: ug/m3
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: stem diameter
Species:
other: Fagus sylvatica
Duration:
6 mo
Dose descriptor:
NOEC
Effect conc.:
>= 2 104 other: ug/m3
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: stem diameter
Species:
other: Trifolium repens
Duration:
1.5 mo
Dose descriptor:
NOEC
Effect conc.:
1 034 other: ug/m3
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: shoot dry weight
Species:
other: Trifolium repens
Duration:
3 mo
Dose descriptor:
NOEC
Effect conc.:
>= 2 179 other: ug/m3
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: shoot dry weight
Species:
other: Molinia caerulea
Duration:
4 mo
Dose descriptor:
NOEC
Effect conc.:
>= 2 029 other: ug/m3
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: shoot dry weight
Species:
other: Vaccinium myrtillus
Duration:
6 mo
Dose descriptor:
NOEC
Effect conc.:
> 252 - < 1 009 other: ug/m3
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: weight of berries
Species:
other: Polytrichum formosum
Duration:
4 mo
Dose descriptor:
NOEC
Effect conc.:
>= 2 101 other: ug/m3
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: re-growth\
Species:
other: Pleurozium schreberi
Duration:
4 mo
Dose descriptor:
NOEC
Effect conc.:
>= 2 101 other: ug/m3
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: re-growth
Species:
other: Rhytidiadelphus squarrosus
Duration:
4 mo
Dose descriptor:
NOEC
Effect conc.:
>= 2 101 other: ug/m3
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: re-growth
Details on results:
The threshold for adverse effects on bean pod yield in early summer was between 11 and 82 microgram m-3. Using the statistical approach described in Appendix II, a NOEC of 46 microgram m-3 was calculated. The same approach was performed for the other species using the representative response parameters. If NOECs could not be derived from the dose-response relationships, the significant difference between treatment levels was used to indicate adverse effects of PER.
Overall, beans from the first experiment proved to be the most sensitive plants in this study, while beans exposed later in the summer did not show any adverse effects of PER, even at concentrations >2056 microgram m-3. Under the (climatic) conditions of the first experiment, bean produced first injury symptoms after only 9 days of exposure at concentrations between 109 and 288 microgram m-3. However foliar injury is irrelevant to yield of crop plants, which in case of bean was reduced at much lower concentrations.
However, in clover from the first experiment, the opposite was observed: although plants showed foliar injury at a concentration of 288 microgram m-3, the NOEC for a reduced shoot biomass production is 1034 microgram m-3. Another finding demonstrating the variable response of different response parameters was that kale did not show any adverse effects on shoot biomass, while chlorophyll contents of the species were somewhat reduced at PER concentrations between 94 and 244 microgram m-3. An overview of species-specific NOECs is presented in Table 6. Growth (timber production) of the two conifers was decreased at concentrations of >320 microgram m-3. In the other tree species beech, effects of
PER on stem diameters (i.e. growth) were absent despite the somewhat increased senescence.

Of the three mosses tested, only Haircap Moss showed some effects of PER after the PER exposure. However, these were very variable and effects of PER on winter re-growth (i.e. survival) were not significant. It must be concluded that regrowth of the three bryophytes was not even affected at concentrations >2101 microgram m-3. While the weight of blueberries was significantly reduced at concentrations >252 microgram m-3, the ear dry weight of wheat was reduced at concentrations above 747 microgram m-3. Opposed to this, the wild graminoid Molinia caerulea did not show significant growth responses to PER.
Results with reference substance (positive control):
Not applicable
Reported statistics and error estimates:
Descriptive statistics was applied to calculate treatment means, standard deviations and coefficients of variation. In order to address dose-response functions for the various response parameters of the different plant species, the linear and nonlinear regression approach was used, applying the best fit in the calculation of regression equations. NOECs are calculated for each of the species according to the following method:

Method to derive individual species-specific NOECs. After calculating the logistic curve of the dose response (formula 1) and determining the 95% confidence level of the asymptote (i.e. the average no effect), the PER concentration corresponding to the lower limit of the confidence level is calculated (formula 2).


Formula 1: y = (C/(1+e^-B(x-M)))
Formula 2: NOEC = M – ((ln(C/yc -1))/B)

Where yc represents the lower limit of the 95% confidence limit of the asymptote. These were calculated with the module Fitnonlinear of the statistical package GENSTAT.

Applicant's summary and conclusion