Slags, sponge iron production by coal reduction in retort

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

bioaccumulation in aquatic species, other

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1993-1994

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented. Study meets generally accepted scientific principles. Study acceptable for assessment (see remarks in the result section)

Principles of method if other than guideline:

Heavy metal accumulation in algae was examined by submersing polished plates of natural rocks and EAF C into Elbe water

GLP compliance:

no

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
The following analogue materials were used for the controls:
Granite
Diabase
Basalt

Radiolabelling:

no

Details on sampling:

In 1993, 5 series of each 6 polished test plates (each one type framed in plastic frame) was exposed to Elbe water, starting on March 24, 1993.
Each one series of stone plates were sampled after 1, 2, 4, 7 and 10 w. Only the 10 w plate was used for bioaccumulation tests (the others were used for determination of the populations of sessile fauna and flora).
In 1994, the stone plates were polished and again exposed to Elbe water, starting on April 13, 1994.
Each one series of stone plates were sampled on
1994-06-21,
1994-07-19,
1994-08-17,
1994-09-14, and
1994-10-04 (2 series, reported as mean of each 2 plates).

Vehicle:

no

Details on preparation of test solutions, spiked fish food or sediment:

The water depth was constant since plastic frames with the stone plates were submersed into the water of the Elbe river from a floating raft at Bunthaus.

Test organisms (species):

other: autotroph (algal) community

Details on test organisms:

Natural algal communities developing on hard substrate surfaces

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural sediment: brackish

Total exposure / uptake duration:

>= 0 - <= 24 wk

Total depuration duration:

ca. 0 wk

Hardness:

not reported

Test temperature:

not reported

pH:

7.4-7.9

Dissolved oxygen:

not reported

TOC:

n.d.

Salinity:

n.d.

Details on test conditions:

ambient conditions reflecting the environmental situation of the early 1990ies

Nominal and measured concentrations:

measured

Reference substance (positive control):

no

Details on estimation of bioconcentration:

The concentration of V in the filtered Elbe water was always below the limit of detection of 2 micrograms/L.

Type:

BAF

Value:

ca. 10 dimensionless

Basis:

whole body d.w.

Remarks:

1993 Comparison of concentration measured for algae grown on EAF C plates in comparison to algae grown on natrual rock plates

Time of plateau:

8 wk

Calculation basis:

other: final data (there was no plateau in the controls)

Remarks on result:

other: V concentration in mussels from contaminated waters (Elbe river in Hamburg) was approximately 1 mg/kg. V concentration in mussels from uncontaminated water bodywater (Gartow lake near Schnackenburg) was approximately 0.15 mg/L

Remarks:

Conc.in environment / dose:In Elbe river water, concentration was always less than 2 µg/L (micrograms/litre)

Elimination:

not specified

Details on kinetic parameters:

No kinetics reported in 1993. However, there are rapid successions of algae in the river water depending e.g. on climate

Metabolites:

not relevant in the context of slags

Results with reference substance (positive control):

not relevant

Details on results:

see below

Reported statistics:

part of the Annex to the report

In 1993, the content of iron and manganese of algae grown in Elbe water on EAF C plates, was doubled in comparision to algae grown on natural rocks. The V content of algae grown on EAF C was increased by a factor of 10 in comparison to other stone plates. Other heavy metal concentrations, e.g. Ag, Cd, Cu, Hg, and Pb, were not elevated.

In 1994, no heavy metal was accumulated in any algae growing on EAF C plates (see overall remarks).

Table 1. Analytical information on sessile algae exposed to Elbe river water while growing on polished stone plates in 1993

	Ag (µg/g)	Al (mg/g)	Cd (µg/g)	Cu (µg/g)	Fe (mg/g)	Hg (µg/g)	Mn (mg/g)	Pb (µg/g)	V (µg/g)	Zn (mg/g)
Granite 1	2.2	17	5.1	81	11	2.87	3.3	97	30	0.83
Granite 2	1.6	16	3.9	70	12	2.2	2.6	68	25	0.75
Diabase 1	2.6	18	6.0	113	12	2.18	3.4	108	30	0.91
Diabase 2	1.9	17	4.6	85	12	2.2	2.8	74	30	0.84
Basalt 1	2.6	18	5.8	108	12	2.51	3.2	126	30	0.92
Basalt 2	1.9	18	4.9	87	14	2.5	3.0	88	35	0.89
EAF C non-porous 1	1.7	17	4.0	92	17	2.29	5.0	72	200	0.83
EAF C non-porous 2	1.7	19	4.8	116	22	2.3	5.8	102	280	1.04
EAF C porous 1	1.9	17	5.1	100	19	2.32	8.2	104	200	0.90
EAF C porous 2	1.4	20	3.6	109	25	2.3	11.0	147	400	1.00

Table 2. Analytical information on sessile algae exposed to Elbe river water while growing on polished stone plates in 1994

21.06.94	Pb (µg/g)	V (µg/g)	Cu (µg/g)	Fe (mg/g)	Mn (mg/g)
Basalt	49	22	202	11.6	1.40
Diabase	51	24	198	11.7	1.40
Granite	50	19	141	10.3	1.39
EAF C non-porous	54	41	198	14.1	1.88
EAF C porous	45	29	198	10.3	2.11
19.07.94
Basalt	42	16	128	6.9	2.24
Diabase	35	13	112	5.6	2.14
Granite	40	15	91	6.9	2.29
EAF C non-porous	51	18	132	9.7	2.48
EAF C porous	53	20	142	8.6	2.54
17.08.94
Basalt	110	12	125	4.9	2.31
Diabase	33	14	109	5.9	2.15
Granite	27	10	93	4.2	2.10
EAF C non-porous	76	23	184	9.8	3.46
EAF C porous	50	15	167	6.9
14.09.94
Basalt	74	30	225	13.7	2.09
Diabase	69	27	252	12.3	2.12
Granite	61	24	213	11.5	1.93
EAF C non-porous	94	31	299	16.4	2.65
EAF C porous	39	14	183	6.7	1.40
04.10.94	Mean of two samples
Basalt	58	21	119	12.3	1.58
Diabase	62	22	110	12.7	1.94
Granite	50	18	60	10	1.72
EAF C non-porous	84	29	161	15.9	2.15
EAF C porous	103	24	159	12.9	2.57

Validity criteria fulfilled:

not applicable

Conclusions:

Apart from V, algae grown on EAF C plates exposed to water of the river Elbe do no accumulate more heavy metals than algae grown on natural rock plates. V is only intermittently accumulated in algae grown on fresh EAF C stone plates newly exposed to the aquatic environment but is of no significance in the long-term behaviour of the slag.

Executive summary:

Heavy metal accumulation in algae was examined by submersing polished plates of natural rocks and EAF C into Elbe water. In algal communities grown on EAF C plates in 1993, there was an increase in the V content to approximately 10 times the level of the algae grown on natural rocks within 10 w. In the second year of exposure, no accumulation of heavy metals occurred in algae grown on EAF C, and it became apparent, that the observed V accumulation was an intermittent effect without relevance for the long-term environmental behaviour of slag in the aquatic environment.

Reference 2

Endpoint:

bioaccumulation in aquatic species: invertebrate

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1993-1994

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented. Study meets generally accepted scientific principles. Study acceptable for assessment

Principles of method if other than guideline:

To elucidate the effect of EAF C leachate on V bioaccummulation Elbe water was enriched with slag leachate and led to mussels which were analyzed for heavy metals

GLP compliance:

no

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
not applicable

Radiolabelling:

no

Details on sampling:

15 mussels each were sampled after 1, 3, 7, 14, 28, and 56 d, both from slag leachate tank as well as from control tank
For water analysis, 100 ml of tank water were taken from each flow trough tank

Vehicle:

no

Details on preparation of test solutions, spiked fish food or sediment:

Elbe water was pumped into a settling tank to remove most of the suspended matter. Unfortunately, no filtration was done, and the suspended matter still in the Elbe water during incubation, was not measured.

Test organisms (species):

other aquatic mollusc: Dreissena polymorpha

Details on test organisms:

Mussels (Dreissena polymorpha) with a shell length of 1.7 to 4.1 cm were used from the Gartow lake close to Schnackenburg (which is considered to be non-contaminated). During the exposure period mussels were not fed because the mussels were able to grow under the experimental conditions by filter feeding of supended matter

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural sediment: brackish

Total exposure / uptake duration:

>= 0 - <= 56 d

Total depuration duration:

ca. 0 d

Hardness:

not reported

Test temperature:

not reported

pH:

7.4-7.9

Dissolved oxygen:

not reported

TOC:

n.d.

Salinity:

n.d.

Details on test conditions:

2 aquaria (flow through tanks each 45 L) were used to elucidate the effect of EAF C leachate on V bioaccummulation. Elbe water was pumped in a settling tank to remove most of the suspended matter. One half of this water was led through a column filled with 4.5 kg of EAF C to enrich the water with EAF C leachate. The other half of the treated Elbe water was used as a control without passage through a slag column. In both flow through tanks approximately 100 mussels were introduced, sampled after 1-56 d, and analyzed for heavy metals.

Nominal and measured concentrations:

measured

Reference substance (positive control):

no

Details on estimation of bioconcentration:

The concentration of V in the filtered Elbe water was always below the limit of detection of 2 micrograms/L. Suspended matter was not completely removed from the flow through water but from the analyzed water.

Type:

BAF

Value:

ca. 7 dimensionless

Basis:

whole body w.w.

Time of plateau:

8 wk

Calculation basis:

other: Comparison of concentration in mussels from contaminated waters (Elbe river in Hamburg) versus concentrations in uncontaminated water body (Gartow lake near Schnackenburg)

Remarks on result:

other: V concentration in mussels from contaminated waters (Elbe river in Hamburg) was approximately 1 mg/kg. V concentration in mussels from uncontaminated water body (Gartow lake near Schnackenburg) was approximately 0.15 mg/L

Remarks:

Conc.in environment / dose:In Elbe river water, concentration was always less than 2 µg/L (micrograms/litre)

Elimination:

not specified

Details on kinetic parameters:

In both mussel groups (exposed to slag leachate and controls) there was a rapid increase of the V concentration when the mussels from the uncontaminated lake were exposed to Elbe water

Metabolites:

not relevant

Results with reference substance (positive control):

not applicable

Details on results:

Slag leachate has no significant effect on the V concentration in these mussel within 56 d.

A bioaccumulation factor cannot be derived for V because these mussels feed on particulate matter suspended in the water column. The Elbe water was filtered before the analysis and was found to contain less than 2 micrograms/L of V. Thus, V uptake by suspended matter cannot be determined, and there is no possibility to estimate a bioaccumulation factor.

Validity criteria fulfilled:

not applicable

Conclusions:

The concentration of V was always below the limit of detection of 2 micrograms/L in the filtered Elbe water. Suspended matter was not completely removed from the test water but presumably from the analyzed water.
Mussels (Dreissena polymorpha) exposed to Elbe water (controls) or to EAF C leachate in Elbe water for up to 56 d accumulated approximately 1 mg/kg of V in both slag leachate exposed mussels as well as in the control mussels. EAF C leachate has no effect on the V accumulation of the mussels.

Executive summary:

To elucidate the effect of EAF C leachate on V bioaccummulation, two aquaria were used in a flow through system. Elbe water was pumped in a settling tank to remove most of the suspended matter. One half of the treated Elbe water was led through a column filled with EAF C to enrich the water with EAF C leachate. The other half of the water was led in a control aquarium without passage through a slag column. In each aquarium approximately 100 mussels (Dreissena polymorpha) were introduced, sampled after 1-56 d, and analyzed for heavy metals.

Mussels exposed to Elbe water (controls) or to EAF C leachate in Elbe water for up to 56 d accumulated approximately 1 mg/kg of V. EAF C leachate had no significant effect on the V accumulation of the mussels. The concentration of V was always below the limit of detection of 2 micrograms/L in the filtered Elbe water. Suspended matter was not completely removed from the Elbe water before incubation but from the Elbe water before the start of the analysis. Thus, no information is available on the V uptake of the mussels from the Elbe water and its suspended matter, and neither a bioaccumulation factor nor a bioconcentration factor can be calculated.

Although EAF C may release V into the environment, its effect on the bioaccumulated V concentration in mussels is negligible under environmental conditions.

Description of key information

Bioaccumulation of trace elements released from slag, is negligible in the environment 

Key value for chemical safety assessment

BCF (aquatic species):

10 dimensionless

Additional information

Ferrous slags are inorganic UVCB similar to natural rock. These materials contain trace elements of toxicological or environmental relevance. The accumulation of these elements was tested in field studies. For several elements tested, there was a high scattering of their concentrations in animals and algae, including controls, but it could not be shown that a significant accumulation of these trace elements occurred.

The BCF 10 was taken as the worst case for heavy metals in aquatic environments to cover for the influence of slags in comparison to natural rock material

Since slags are inorganic UVCB similar to natural rock, there is no need to perform any study on bioaccumulation.

Rejected Study

To elucidate the possible bioaccumulation of trace metals released from slag stones used in hydraulic engineering, slags were exposed to Rhine water. Dikerogammarus villosus (Amphipoda, Crustaceae), Bithynia tentaculata (Gastropoda), the mussels Corbicula fluminea and Dreissena polymorpha (Bivalvia), and the macrozoobenthos (sessile heterotrophes) were used to monitor bioaccumulation of trace elements which were assumed to be derived from slags. Basalt was used as control.

There were no data available for Dikerogammarus villosus, and there were in approximately 60 % of the measurements higher concentrations of trace metals (Cu, Pb, Cr and Ni) in slag-exposed organisms than in basalt-exposed organisms.

The author interpreted the data as evidence for relevant bioaccumulation:

Cu: As the control animals in contact with basalt had much higher Cu concentrations than the animals in the BOS (5-50 mm) baskets, it was assumed that there was an analytical error and the data were not taken into account for the overall assessment.

Pb, Cr, Ni: It was assumed that there was a relevant bioaccumulation in the bodies of the animals and in the sessile organisms on the slag-exposed organisms.

The interpretation of the author is not followed:

There was a large scattering in the concentrations of the 4 elements examined (Cu, Pb, Cr, and Ni). The concentrations of these metals in slag-exposed organisms were less than 1 % to up to 70 times the value of basalt-exposed organisms. The highest values were obtained in Bithynia tentaculata for Cr and in Corbicula fluminea for Ni. In both cases the bioaccumulation, as calculated from the ratio of concentrations in slag versus basalt-exposed concentrations, was high because the basalt controls were approximately one order of magnitude lower than in the other organisms. Taking into account that 40 % of the values of slags are lower than the control values, the data suggest that there was no significant bioaccumulation and there were no relevant differences between organisms exposed to slag and basalt.