Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 932-476-9 | CAS number: -
Ferrous slags are not inhibitory to key metabolic activities of soil microorganisms.
It was shown by laboratory and field studies that ferrous slags are not inhibitory to key metabolic activities of soil microorganisms i.e. respiration. Nitrogen metabolism and cellulose degradation were also shown not to be inhibited, but even slightly activated.
Laboratory guideline study
To test the effects of slags, ferrous metal, blast furnace (air-cooled – ABS) on the soil microflora as an indicator for conservation of soil fertility, the metabolic activity of microbial biomass and its nitrogen conversion potential were determined. The tests were performed according to C.22 (Soil Microorganisms: Carbon Transformation Test)(identical to OECD-Guideline No. 217) and C.21 (Soil Microorganisms: Nitrogen Transformation Test) of the EU-Regulation440/2008 (identical to OECD-Guideline 216). The metabolic activity of the microbial biomass was influenced only temporarily by the slag in the acclimatisation phase. The respiratory activity (carbon transformation test) in the soil mixtures treated with 10 g test item / kg of soil (dry matter) was negatively affected only at the start of the incubation period t0 (28% reduction). At the later time points, the differences between slag-incubated and control soils were less than ± 25 %. After 28 d, the microbial respiration of the soil was slightly increased in the treatment with 10 g/kg soil dry matter in comparison to the controls.
The nitrogen conversion (ammonification and nitrification) of lucerne meal (alfalfa) which was added to the soil, was not negatively influenced by the slags applied at a dose of 10 g / kg (dry matter). In general, the deviations of the NO3-- and NO2--nitrogen values of the treated samples from the untreated ones were <25%. In regard to nitrogen metabolism, ABS served as a fertilizer.
Slags, ferrous metal, blast furnace (air-cooled – ABS) had no relevant effect on the activity of the soil microflora even in the highest concentration tested (10 g/kg) for 28 d (SGS 2010).
Extended laboratory study
To evaluate the effects of steelmaking slags (SMS) on soil microorganisms, in laboratory experiments SMS was added to oxisol soil at concentrations of 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). Dry matter production, pH and metal uptake into Sorghum bicolor plants raised in parallel experiments in pot were plotted against each other and a correlation analysis was performed.
The dry matter production of Sorghum bicolor was highest when the concentration of SMS added to oxisol was approximately 9.6 t/ha. Uptake of Ca, Mg, Fe, Mn and Zn shows a flat maximum at 7 -10 t/ha in regard to the concentration of slag in the oxisol (controls not reported). The uptake of Cu was independent of the slag concentration whereas the Ni content was low but increased with increasing concentration of slag in the range tested, and in parallel to the pH.
Minimum of microbial respiration occured at a SMS concentration of approximately 10 t/ha. This minimum is explained by the authors by pH controlled availability of metal ions. Although this hypothesis cannot be verified, it is apparent that the inhibition of microbial respiration is not caused by high slag concentration in the soil, as the microbial respiration recovered at the highest slag concentration tested (Costa et al. 1992).
To assess the applicability of slags as agricultural fertilizers in regard to soil microorganims, agricultural research done at the Sommerland Agricultural Research Station was reviewed. The metabolic potential of soil microorganisms had been measured as respiration rate and cellulose degradation with the ferrous slags ABS
(slags, ferrous metal, blast furnace, air-cooled) and BOS (slags, steelmaking, converter).
The agricultural yields was highest in slag treated fields (approximately 5 % above controls), The soil respiration in controls was 420 mg CO2/kg soil. It was highest in lime-treated fields (580 mg CO2/kg soil), and 490 and 550 mg CO2/kg soil in ABS- and BOS-treated fields, respectively. Microbial cellulose degradation was lowest in control soils (1.4 mg/cm2) and highest in the slags: ABS 2 mg/cm2, and BOS 2.3 mg/cm2.
The ferrous slags ABS (slags, ferrous metal, blast furnace, air-cooled) and BOS (slags, steelmaking, converter) did not inhibit the microbial respiration and cellulose degradation potential of soils.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
Welcome to the ECHA website. This site is not fully supported in Internet Explorer 7 (and earlier versions). Please upgrade your Internet Explorer to a newer version.
Close Do not show this message again