Slags, sponge iron production by coal reduction in retort

Sediment toxicity

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

sediment toxicity: 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

Key result

Duration:

624 wk

Dose descriptor:

NOEC

Effect conc.:

> 10 other: g/kg sediment

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

other: structure and development of benthal communities

Remarks on result:

other: estimate made by Dossier editor

Validity criteria fulfilled:

yes

Conclusions:

BOS: fiels study, benthic communities: (chronic) NOEC > 10 g/kg sediment (estimated)

Executive summary:

To determine the toxicity of slags to sediment related organisms in the river Rhine, a field study was undertaken which monitored the communities in fields of slags, steelmaking, converter (BOS), basalt and greywacke. Seize, structure and development of bentic fauna was determined in several river bank reinforcement fields constructed of these materials.

The pH of sediments in the slag fields was higher than of sediments in fields of natural stones. The oxygen concentrations in the interstitial of the fields decreased to the same values independent of the nature of the accompanying stone material.

No inhibitory influence of BOS was detected on the settlement of macroinvertebrates. Within the river enforcement there was a higher number of species in the slag fields than in the natural stones fields. The benthic habitat quality was most significantly affected by the proportion of small grain-sized material, which inhibits the colonization the substrate because of permanent material rearrangements (Bundesanstalt fuer Gewaesserkunde 1986).

Reference 2

Endpoint:

sediment toxicity: short-term

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

There are no indications from the current information that this study is required.

Reason / purpose for cross-reference:

data waiving: supporting information

Description of key information

No special studies on sediment toxicity to benthic organisms are available but several observations suggest that slags do not negatively influence the sediment quality and that slags are excellent substrate for growth of benthos.

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater sediment:

100 000 mg/kg sediment dw

EC10, LC10 or NOEC for marine water sediment:

100 000 mg/kg sediment dw

Additional information

In a field study it has been shown that benthic organisms growing on slags (BOS) exhibited even greater species diversity and population density than on natural rock. So no negative influence of slags on benthic organisms could be detected. Therefore a NOEC = 100 g/kg was taken as a default value for calculations.