Nickel dihydroxide

Endpoint summary

Additional information

Nickel is an ubiquitous trace metal and occurs in soil, water, air, and in the biosphere. The average content in the earth's crust is about 0.008%. Farm soils contain between 3 and 1000 mg nickel/kg. Levels in natural waters have been found to range from 2 to 10 μg/litre (fresh water) and from 0.2 to 0.7 μg/litre (marine). Atmospheric nickel concentrations for remote areas that are considered to be relatively free from man-made nickel emissions are in the range of 0.1-1 ng/m3 (marine) and 1-3 ng/m3 (continental) (Schmidt & Andren, 1980).

The transport and distribution of nickel particles to, or between, different environmental compartments is strongly influenced by particle size and meteorological conditions.

Air:

Atmospheric nickel is considered to exist mainly in the form of particulate aerosols containing different concentrations of nickel, depending on the source. The highest nickel concentrations in ambient air are usually found in the smallest particles. Nickel carbonyl is unstable in air and decomposes to form nickel oxide.

Soil:

Depending on the soil type, nickel may exhibit a high mobility within the soil profile finally reaching ground water and, thus, rivers and lakes. The amount of nickel uptake from soil depends on various geochemical and physical parameters including the type of soil, the soil pH and humidity, the organic matter content of the soil, and the concentration of extractable nickel. In a soil-water system, nickel may form complexes with inorganic ligands (Cl-, OH-, SO42-, or NH3) (Richter & Theiss, 1980) and organic ligands (e.g., humic or fulvic acids) (Nriagu, 1980).

Water:

Nickel is introduced into the hydrosphere by removal from the atmosphere, by surface run-off, by discharge of industrial and municipal waste, and also following natural erosion of soils and rocks. In rivers, nickel is mainly transported in the form of a precipitated coating on particles and in association with organic matter; in lakes, it is transported in the ionic form, also mainly in association with organic matter. The fate of nickel in freshwater and sea water is affected by several factors including pH, pE, ionic strength, type and concentration of organic and inorganic ligands, and the presence of solid surfaces for adsorption (Snodgras, 1980). In natural waters, at a pH range of 5-9, the divalent ion Ni2+ (Ni(H2O)62+) is the dominant form. In this pH range, nickel may also be adsorbed on iron and manganese oxides, or form complexes with inorganic ligands (OH-, SO42-, Cl- or NH3) (Richter & Theiss, 1980).

Reference: IPCS INCHEM - EHC (1991). Nickel - Environmental health criteria 108

"All five nickel compounds (nickel chloride, nickel dinitrate, nickel hydroxycarbonate, nickel sulphate, nickel metal) release Ni2+ into the environment, and partitioning coefficients for this ionic form are therefore relevant for all five substances. Ni2+ partitioning coefficient for solid-water in suspended matter (Kp susp) is 26303 (log Kp susp = 4.42). Ni2+ partitioning coefficient for sediment-porewater (Kp sed) is 7,079 (log Kp sediment = 3.85). Ni2+ partitioning coefficient for soil-water (Kp soil) is 726 (log Kp soil = 2.86). Ni2+ partitioning coefficients were based on 50th percentiles of distributions of values from available high quality data".

Reference: OECD (2008). SIAP on Nickel and Nickel compounds