Slags, sponge iron production by coal reduction in retort

Toxicity to terrestrial plants

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

The available identification data for the Target and the Source substance support the read-across hypothesis. Adequate, reliable and available scientific information indicate that the Target and Source substance have, or are very likely to have, similar (eco)toxicological properties. There are no indications that constituents other than those identified for the substances or impurities may influence the validity of the read-across. There is no evidence that additional toxicological mechanisms, other than those identified in the read-across hypothesis, may be acting or have an adverse effect on the validity of the read-across.

Reason / purpose for cross-reference:

read-across source

Key result

Species:

Triticum aestivum

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

> 10 000 mg/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

seedling emergence

Key result

Species:

Sinapis alba

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

> 10 000 mg/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

seedling emergence

Key result

Species:

Lepidum sativum

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

> 10 000 mg/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

seedling emergence

Key result

Species:

Triticum aestivum

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

> 10 000 mg/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Sinapis alba

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

> 10 000 mg/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Lepidum sativum

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

> 10 000 mg/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Triticum aestivum

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

> 10 000 mg/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

other: survival

Key result

Species:

Sinapis alba

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

> 10 000 mg/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

other: survival

Key result

Species:

Lepidum sativum

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

> 10 000 mg/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

other: survival

Validity criteria fulfilled:

yes

Conclusions:

ABS: OECD 2TG 208, wheat (Triticum aestivum), mustard (Sinapis alba), and cress (Lepidium sativum) growth, survival, emergence, all 21d-EC10 > 10000 mg/kg soil dw.

Executive summary:

To evaluate the possible ecotoxicity of slags under guideline conditions in the laboratory, slags, ferrous metal, blast furnace (air cooled – ABS) were tested by a single application according to the OECD Guideline 208 in regard to seedling emergence and early stages of growth of the three terrestrial plants, wheat (Triticum aestivum), mustard (Sinapis alba), and cress (Lepidium sativum). The LC₅₀ of emergence refers to the appearance of the seedlings above the soil surface, being the concentration of slag at which the emergence rate is 50% of that of the controls. The EC₅₀ of growth is determined from the shoot fresh weight and is the concentration of slag at which the decrease in growth is 50% of that of the control. The test item was tested up to a maximum concentration of 10000 mg/kg soil dw which exceeds the maximum of concentration given by the test guideline OECD 208 by a factor 10.

 

No significant inhibitory effect was exerted by slag on growth (shoot fresh weight), survival, and emergence of any of the three species wheat (Triticum aestivum), mustard (Sinapis alba), and cress (Lepidium sativum) up to the maximum concentration of 10,000 mg/kg dw soil. All 21d-EC₁₀are > 10000 mg/kg soil dw.

Reference 2

Endpoint:

toxicity to terrestrial plants: long-term

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

The available identification data for the Target and the Source substance support the read-across hypothesis. Adequate, reliable and available scientific information indicate that the Target and Source substance have, or are very likely to have, similar (eco)toxicological properties. There are no indications that constituents other than those identified for the substances or impurities may influence the validity of the read-across. There is no evidence that additional toxicological mechanisms, other than those identified in the read-across hypothesis, may be acting or have an adverse effect on the validity of the read-across.

Reason / purpose for cross-reference:

read-across source

Principles of method if other than guideline:

Ecological field study using the Zeigerwerte of Ellenberg (indicator values according to Ellenberg ) to plants growing on a blast furnace slag deposit

Key result

Species:

other: field study: vegetation analysis

Duration:

540 mo

Dose descriptor:

NOEC

Effect conc.:

ca. 1 000 000 mg/kg soil ww

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

other: effects of heavy metals: Selection of metalophytes

Details on results:

In total, 95 species of flowering plants, 1 fern species, and 6 mosses, were identified on the slag dump of Donawitz. Additionally, 5 fungi and 2 lichens were found.

Validity criteria fulfilled:

yes

Conclusions:

Slags as a growth substrate for plants do not induce the selection of a metalophytic vegetation

Executive summary:

To identify the effects of slags, ferrous metal, blast furnace (ABS) on the environment, the vegetation on the slag deposit of Donawitz on the slopes of the Baernerkogel, which was deposited from 1935 to 1942, was examined in this study. The deposit, as a growth site for plants, is characterized by light (southward slope), dryness (efficient drainage), basic substrate, and nutrient deficiency, especially in regard to phosphorus and nitrogen.

In total, 95 species of flowering plants, 1 fern species, and 6 mosses, were identified on the slag deposit of Donawitz. Addionally, 5 species of fungi and 2 lichens were found.

The plant succession is characteristic for extremely nutrient-deficient and well-drained raw soil and represents the Tortella inclinata -stadium of (pioneer) vegetation.

Although zinc, manganese and iron are present in the slags at significant concentrations, the author reports no effect of heavy metal toxicity in the vegetation on the slag, and he clearly states that there is no heavy metal vegetation onsite.

Reference 3

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

The available identification data for the Target and the Source substance support the read-across hypothesis. Adequate, reliable and available scientific information indicate that the Target and Source substance have, or are very likely to have, similar (eco)toxicological properties. There are no indications that constituents other than those identified for the substances or impurities may influence the validity of the read-across. There is no evidence that additional toxicological mechanisms, other than those identified in the read-across hypothesis, may be acting or have an adverse effect on the validity of the read-across.

Reason / purpose for cross-reference:

read-across source

GLP compliance:

not specified

Reference substance (positive control):

yes

Key result

Species:

Hordeum vulgare

Duration:

7 d

Dose descriptor:

NOEC

Effect conc.:

410 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

germination

Key result

Species:

Hordeum vulgare

Duration:

7 d

Dose descriptor:

LOEC

Effect conc.:

510 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

germination

Key result

Species:

Hordeum vulgare

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

630 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

germination

Key result

Species:

Hordeum vulgare

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

410 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Hordeum vulgare

Duration:

14 d

Dose descriptor:

LOEC

Effect conc.:

510 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Hordeum vulgare

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

570 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth

Remarks on result:

other: report on EC50 of 66 % is a typing error according to the other results available

Key result

Species:

Lactuca sativa

Duration:

7 d

Dose descriptor:

NOEC

Effect conc.:

120 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

germination

Key result

Species:

Lactuca sativa

Duration:

7 d

Dose descriptor:

LOEC

Effect conc.:

210 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

germination

Key result

Species:

Lactuca sativa

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

230 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

germination

Key result

Species:

Lactuca sativa

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

120 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Lactuca sativa

Duration:

14 d

Dose descriptor:

LOEC

Effect conc.:

210 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Lactuca sativa

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

260 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth

Results with reference substance (positive control):

not reported

Validity criteria fulfilled:

yes

Conclusions:

ABS: ISO 11269-2 and NF X 31201, Hordeum vulgare (barley) : 7 d-NOEC = 410 g/kg (germination), 14 d-NOEC = 410 g/kg (growth). Lactuca sativa (lettuce): 7 d-NOEC 120 g/kg (germination), 14 d-NOEC 120 g/kg (growth)

Executive summary:

In germination and growth tests according to ISO 11269-2 and NF X 31201, ABS was not toxic to germination and growth (dry matter increase) of Hordeum vulgare (barley) and Lactuca sativa (lettuce). The NOECs were 410 g/kg for both germination and growth of barley and 120 g/kg for both germination and growth of lettuce after 7 d and 14 d, respectively.

Reference 4

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

The available identification data for the Target and the Source substance support the read-across hypothesis. Adequate, reliable and available scientific information indicate that the Target and Source substance have, or are very likely to have, similar (eco)toxicological properties. There are no indications that constituents other than those identified for the substances or impurities may influence the validity of the read-across. There is no evidence that additional toxicological mechanisms, other than those identified in the read-across hypothesis, may be acting or have an adverse effect on the validity of the read-across.

Reason / purpose for cross-reference:

read-across source

Key result

Species:

Hordeum vulgare

Duration:

7 d

Dose descriptor:

NOEC

Effect conc.:

510 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

germination

Key result

Species:

Hordeum vulgare

Duration:

7 d

Dose descriptor:

LOEC

Effect conc.:

640 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

germination

Key result

Species:

Hordeum vulgare

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

750 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

germination

Key result

Species:

Hordeum vulgare

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

640 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Hordeum vulgare

Duration:

14 d

Dose descriptor:

LOEC

Effect conc.:

800 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Hordeum vulgare

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

860 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth

Remarks on result:

other: report on EC50 of 66 % is a typing error according to the other results available

Key result

Species:

Lactuca sativa

Duration:

7 d

Dose descriptor:

NOEC

Effect conc.:

410 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

germination

Key result

Species:

Lactuca sativa

Duration:

7 d

Dose descriptor:

LOEC

Effect conc.:

510 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

germination

Key result

Species:

Lactuca sativa

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

540 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

germination

Key result

Species:

Lactuca sativa

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

410 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Lactuca sativa

Duration:

14 d

Dose descriptor:

LOEC

Effect conc.:

510 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Lactuca sativa

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

530 g/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth

Validity criteria fulfilled:

yes

Conclusions:

ABS: ISO 11269-2 and NF X 31201, Hordeum vulgare (barley) : 7 d-NOEC = 510 g/kg (germination), 14 d-NOEC = 640 g/kg (growth). Lactuca sativa (lettuce): 7 d-NOEC = 410 g/kg (germination), 14 d-NOEC = 410 g/kg (growth)

Executive summary:

In germination and growth tests according to ISO 11269-2 and NF X 31201, ABS was not toxic to germination and growth (dry matter increase) of Hordeum vulgare (barley) and Lactuca sativa (lettuce). The NOECs were 510 g/kg for germination and 640 g/kg for growth of barley and 410 g/kg for both germination and growth of lettuce, after 7 and 14 d, respectively.

Reference 5

Endpoint:

toxicity to terrestrial plants: long-term

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

The available identification data for the Target and the Source substance support the read-across hypothesis. Adequate, reliable and available scientific information indicate that the Target and Source substance have, or are very likely to have, similar (eco)toxicological properties. There are no indications that constituents other than those identified for the substances or impurities may influence the validity of the read-across. There is no evidence that additional toxicological mechanisms, other than those identified in the read-across hypothesis, may be acting or have an adverse effect on the validity of the read-across.

Reason / purpose for cross-reference:

read-across source

GLP compliance:

no

Key result

Species:

Brassica rapa

Duration:

12 mo

Dose descriptor:

other: yield

Effect conc.:

ca. 1 200 kg/ha

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: yield

Key result

Species:

Triticum aestivum

Duration:

12 mo

Dose descriptor:

other: yield

Effect conc.:

ca. 1 200 kg/ha

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: yield

Validity criteria fulfilled:

yes

Remarks:

tests performed at several places in Gerany and Austria, mostly independent of each other

Conclusions:

Agricultural yield is increased by application of ABS/GBS, BOS, and SMS (ladle slags) as fertilizers. These slags were more effective than limestone or burnt lime. There was no relevant accumulation of trace elements neither in soil nor in plant matter.

Executive summary:

Field studies in Germany and Austria of up to 50 years duration demonstrated improved agricultural yield by application of slags, ferrous metal, blast furnace (ABS/GBS), slags, steelamking, converter (BOS), and slags, steelmaking (ladle slags, SMS) as fertilizers, in comparison to liming with limestone (CaCO3) or burnt lime (CaO).

The application of ABS/GBS and SMS in amounts of annual lime loss did not lead to significant increases of the Cr or V content in the soils. Although the long-term use of BOS caused an slight accumulation of aqua regia extractable Cr and V in the soils, all slag applications led to improved soil fertility also in comparison to liming with burnt lime or limestone, and did not negatively affect the microbiological activities in soils. There is no risk of trace element accumulation in soils or plants (Rex 2005).

Reference 6

Endpoint:

toxicity to terrestrial plants: long-term

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

The available identification data for the Target and the Source substance support the read-across hypothesis. Adequate, reliable and available scientific information indicate that the Target and Source substance have, or are very likely to have, similar (eco)toxicological properties. There are no indications that constituents other than those identified for the substances or impurities may influence the validity of the read-across. There is no evidence that additional toxicological mechanisms, other than those identified in the read-across hypothesis, may be acting or have an adverse effect on the validity of the read-across.

Reason / purpose for cross-reference:

read-across source

GLP compliance:

no

Key result

Species:

other: Tilia cordata

Duration:

36 mo

Dose descriptor:

other: viability

Effect conc.:

> 100 g/kg soil dw

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

phytotoxicity

Key result

Species:

other: Acer pseudoplatanus

Duration:

36 mo

Dose descriptor:

other: viability

Effect conc.:

> 100 g/kg soil dw

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

phytotoxicity

Validity criteria fulfilled:

yes

Conclusions:

Slags do not inhibit tree growth near roads

Executive summary:

The growth of trees planted close to road sections constructed from slags (ABS, SMS) or natural rock (as controls) under regular and stagnant moisture condions was monitored for three years. Trees from 151 sites near existing roads were monitored in regard to their viability.

The mean SO₄^2-concentration in soil and the total sulfur content of leaves was not influenced by the sulfur content of the slag material used in road construction. There were no relevant differences in the content of several trace elements or in the viability of trees planted near the road test sections.

Slag as a road construction material of existing roads had no adversive effect on the viability of trees planted near these roads. The viability of trees in the vicinity of slag roads was much better than in the vicinity of roads from natural rock material, presumably due to the fertilizing and pH buffering effect of slags.

Reference 7

Endpoint:

toxicity to terrestrial plants: long-term

Type of information:

other: review

Adequacy of study:

supporting study

Study period:

1992

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Documentation insufficient for assessment (e.g. no literature references supplied)

Principles of method if other than guideline:

compilation of data (lysimeter studies, field studies) from several (unknown) sources

GLP compliance:

no

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
The reference material in the tree vigour test was a mineral layer in combination with a sand drainage layer and an impermeable layer with a membrane to accumulate water to simulate worst case (elevated water table)

Analytical monitoring:

not specified

Details on sampling:

no data

Vehicle:

no

Details on preparation and application of test substrate:

several slags used in road construction or hydraulic engineering
natural rocks as references

Species:

other: road trees

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

no details reported (some trees were specially planted for testing purposes, others were planted near road without intention of testing

Test type:

other: several tests reported e.g. vegetative vigour tests on road side trees

Study type:

other: field and laboratory

Substrate type:

natural soil

Limit test:

no

Remarks:

Lysimeter test: short term study. Road layer test: long term study (Exposure is several years depending on year of construction of (test) road and planting of trees)

Post exposure observation period:

in field studies no post exposure period since exposure continued

Test temperature:

ambient Central European climate

pH:

neither systematically monitored nor systematically reported

Moisture:

lysimeter tests: water rinsing test as a worst case
field tests: depending on rain fall

Details on test conditions:

Several experiments reported to elucidate the influence of slag used as base layer in roadmaking (e.g. measured directly under the slag, 1 m or 1.5 m deeper in the soil). Documentation incomplete and not suited to evaluate data

Nominal and measured concentrations:

not applicable

Reference substance (positive control):

no

Remarks:

field and other tests

Details on results:

Slags do not have any inhibitory effect on plants (trees), whatever slags are used for (road construction, river bed stabilisation, lake shore protection)

Results with reference substance (positive control):

not applicable

Reported statistics and error estimates:

no data reported

Validity criteria fulfilled:

no

Remarks:

review, insufficient information on data source

Conclusions:

There is no evidence that slags diminish the vigour of road side trees

Executive summary:

Some data on the effects of slags on plants in the environment, especially near roads, were reviewed (review not valid). There is no evidence that slags diminish the vigour of road side trees.

Description of key information

Ecotoxicite de certains coproduits siderurgiques:

ABS: ISO 11269-2 and NF X 31201, Hordeum vulgare (barley) : 7 d-NOEC = 510 g/kg (germination), 14 d-NOEC = 640 g/kg (growth). Lactuca sativa (lettuce): 7 d-NOEC = 410 g/kg (germination), 14 d-NOEC = 410 g/kg (growth)

Ecotoxicite de certains coproduits siderurgiques:

ABS: ISO 11269-2 and NF X 31201, Hordeum vulgare (barley) : 7 d-NOEC = 410 g/kg (germination), 14 d-NOEC = 410 g/kg (growth). Lactuca sativa (lettuce): 7 d-NOEC 120 g/kg (germination), 14 d-NOEC 120 g/kg (growth)

Zur Vegetation von Hochofenschlackenhalden:

Slags as a growth substrate for plants do not induce the selection of a metalophytic vegetation

 

Study on the toxicity towards terrestrial plants of slags, ferrous metal, blast furnace (air cooled – ABS) according to OECD Guideline 208 adopted 19-July-2006:

ABS: OECD 2TG 208, wheat (Triticum aestivum), mustard (Sinapis alba), and cress (Lepidium sativum) growth, survival, emergence, all 21d-EC10 > 10000 mg/kg soil dw.

Einfluss von Strassenbaustoffen aus Eisenhuetttenschlacken auf den Vitalitaetszustand von Strassenbaeumen:

Slags do not inhibit tree growth near roads

The use of BF, converter and ladle slags in European agriculture - benefits or risk:

Agricultural yield is increased by application of ABS/GBS, BOS, and SMS (ladle slags) as fertilizers. These slags were more effective than limestone or burnt lime. There was no relevant accumulation of trace elements neither in soil nor in plant matter.

Umweltverhalten von Eisenhuettenschlacken in der Praxis:

There is no evidence that slags diminish the vigour of road side trees

ABS: Hordeum vulgare (barley)  ISO 11269-2 and NF X 31201: 14 d-NOEC 510 g/kg (germination), 640 g/kg (growth). Lactuca sativa (lettuce): 410 g/kg (both germination and growth)

Slags are effiecient fertilizers for plants

The chronic NOEC is estimated to be 100 g/kg soil for weathered slags.

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for terrestrial plants:

100 000 mg/kg soil dw

Additional information

Laboratory guideline studies on acute toxicity

To evaluate the possible ecotoxicity of slags under guideline conditions in the laboratory, slags, ferrous metal, blast furnace (air cooled – ABS) were tested by a single application according to the OECD Guideline 208 in regard to seedling emergence and early stages of growth of the three terrestrial plants, wheat (Triticum aestivum), mustard (Sinapis alba), and cress (Lepidium sativum). The LC₅₀of emergence refers to the appearance of the seedlings above the soil surface, being the concentration of slags at which the emergence rate is 50 % of that of the controls. The EC₅₀of growth is determined from the shoot fresh weight and is the concentration of slags at which the decrease in growth is 50 % of that of the control. The slags were tested up to a maximum concentration of 10000 mg/kg soil dw which exceeds the maximum of concentration given by the test guideline OECD 208 by a factor 10.

 

No significant inhibitory effect was exerted by slags on growth (shoot fresh weight), survival, and emergence of any of the three species wheat (Triticum aestivum), mustard (Sinapis alba), and cress (Lepidium sativum) up to the maximum concentration of 10000 mg/kg dw soil. All 21d-EC₁₀ are > 10000 mg/kg soil dw (Fresenius 2010).

In germination and growth tests according to ISO 11269-2 and NF X 31201, ABS did not affect germination and growth (dry matter increase) of Hordeum vulgare (barley) and Lactuca sativa (lettuce). The NOECs were 510 g/kg for germination and 640 g/kg for growth of barley and 410 g/kg for both germination and growth of lettuce (LECES 1999).

Extended laboratory study

The effect of steelmaking slags (SMS) added to oxisol soil was evaluated for Sorghum spec. In extended laboratory experiments sorghum plants were grown for 36 days in pots in oxisol with SMS added up to 21.2 t/ha. The pH varied between 4.8 (controls) and 7.4 (SMS, 21.2 t/ha, no pH controls done). The dry matter production and the metal content in plants were plotted against each other and a correlation analysis was performed.

The dry matter production of sorghum was highest when the concentration of SMS added to oxisol was approximately 9.6 t/ha. The study clearly shows that SMS functions as a liming agent/fertilizer for sorghum in sightly acidic oxisol (Costa et al. 1992).

Field studies on chronic toxicity

Field studies in Germany and Austria of up to 50 years duration demonstrated improved agricultural yield by application of slags, ferrous metal, blast furnace (ABS/GBS), slags, steelmaking, converter (BOS), and slags, steelmaking (ladle slags, SMS) as fertilizers, in comparison to liming with limestone (CaCO₃) or burnt lime (CaO).

The application of ABS/GBS and SMS in amounts of annual lime loss did not lead to significant increases of the Cr or V content in the soils. Although the long-term use of BOS caused an slight accumulation of aqua regia extractable Cr and V in the soils, all slag applications led to improved soil fertility also in comparison to liming with burnt lime or limestone, and did not negatively affect the microbiological activities in soils. There is no risk of trace element accumulation in soils or plants (Rex 2005).

The growth of trees planted close to road sections constructed from slags (ABS, SMS) or natural rock (as controls) under regular and stagnant moisture conditions was monitored for three years. Trees from 151 sites near existing roads were monitored in regard to their viability.

The mean SO₄^2-concentration in soil and the total sulfur content of leaves was not influenced by the sulfur content of the slag material used in road construction. There were no relevant differences in the content of several trace elements or in the viability of trees planted near the road test sections.

Slag as a road construction material of existing roads had no adversive effect on the viability of trees planted near these roads. The viability of trees in the vicinity of slag roads was much better than in the vicinity of roads from natural rock material, presumably due to the fertilizing and pH buffering effect of ferrous slags (FEhS 1991).