Examination of the composition and structure of oxidic components in dust released into the air at the work place during manufacture and processing of metallic materials containing nickel (dusts containing nickel)

Status:

completed 03/1999

Aims:

The manufacture, processing and treatment of nickel alloys can result in the appearance of dusts containing nickel which can be inhaled. In the "register of carcinogenic ... substances" (TRGS 905) nickel and Ni-carbonate are categorised as K3, nickel oxide and nickel sulphide as K1. A threshold limit value applies as a MAK (maximum acceptable concentration) for nickel and Ni-carbonate in the air at the work place (TRGS 900 in accordance with Bundesarbeitsblatt 4/1995), and a TRK (technical guidance concentration) value applies for Ni-oxide, Ni-sulphide (and pyritiferous ores). For the operational monitoring in the work place the problem arises as to which kind of limit value to apply at any one time, as only the Ni-content can be determined as an analytical basis for calculation in normal analytical processes. There are also indications of the formation of spinels, i.e. metallic complexes containing nickel which, because of their biological insolubility, are possibly completely non-toxic. Goal: quantitative analysis of nickel compounds, which occur in the dust in certain working areas or as a result of certain working processes; determination of key components for work place monitoring; determination of the occurrence of spinels and, where applicable, the corresponding parameters.

Activities/Methods:

Examination of dust taken from work places and parallel with man made mixtures of Ni, NiO and nickel complexes; quantitative analysis of Ni (ESR/FMR), NiO and Ni-complexes (XRD, ESMA, IR); determining solubility, analysis of dissolved and non-dissolved compounds (AAS, XRD, DSMA, IR)

Results:

Basic findings concerning nickel oxide structures; suggestion for measuring and assessment procedures for dangerous nickel oxides at the work place dependent on working material and working procedure.

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