Nickel Forum

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Nickel in the Environment: Present Status

Background

Nickel was discovered some 250 years ago. It is a metallic element and the fifth most abundant after iron, oxygen, silicon and magnesium. Links to certain serious illnesses have been recognized for over 100 years and controlled through significant steps taken to minimize occupational exposure through process improvement.

Nickel is mostly melted with other metals to form alloys. There are an estimated 3000 nickel-containing alloys in daily use. The range of nickel alloy properties includes superior toughness, strength, corrosion resistance, special magnetic and electronic properties and the ability to withstand extremes of temperature.

Nickel is plentiful and over a million tonnes is produced each year worldwide by mining, milling, smelting and refining operations. However, it is also one of the most recycled materials in today’s global economy. Add to that the fact that most nickel containing products have a long service life – on average over 25 years – and you have a substance that makes a major contribution towards sustainable development.

An environmental risk assessment requires an analysis (effect assessment) to be conducted to determine the "safe" level of nickel in the environment. This is called the predicted no effect concentration (PNEC¹). This value is compared with the predicted environmental concentration (PEC²) which is part of the exposure assessment.

The PEC is divided by the PNEC and if the resulting risk characterization ratio (RCR) is > 1, risk to the environment is assumed. This analysis is conducted for water-dwelling organisms, sediment-dwelling organisms, soil-dwelling organisms, and microorganisms in sewage treatment plants.

The scientific basis of the risk assessment evolves from the premise that the nickel ion is the putative toxic agent.

In March, 2002, the Rapporteur (Denmark) released a first-draft report on the health hazards of nickel metal and soluble nickel, and of nickel hazards in the environment (soils and water).

Current situation

The Rapporteur (Denmark) has submitted a draft effects assessment for the environment (PNEC). The PNECs or "safe" nickel levels are very low and in many cases below average nickel levels already found in the environment.

The PEC (exposure) analysis is not yet complete, but given the very low PNECs, a conclusion of risk to the environment is anticipated if the PNECs do not change.

There is little environmental data on nickel that describes its long-term effects in non-mammalian organisms. There is also a serious lack of information on bioavailability of nickel in the environment.

Bioavailability is a key factor for metals because it is the potential for the release of free bioavailable nickel ions that is important in terms of potential toxicity/hazard rather than the total nickel content in the environment.

The EU risk assessment will be used to drive regulation on nickel not only in Europe but also worldwide as the OECD will also be reviewing the EU assessment results.

Currently the assessments are based on the total amount of nickel in the environment without regard for the amount of bioavailable nickel. These are serious data gaps and are part of the reason that the PNECs are so low. This is compounded by the fact that the EU guidelines and methodology for environmental risk assessment are in their infancy and do not fully address all the factors related to naturally occurring metallic elements.

Implications for nickel industry

If the PNECs generated in this analysis are accepted and used to set new and lower acceptable levels of nickel in the environment, there will be significant implications for industry. Industries that discharge nickel or produce nickel products would face new and much stricter nickel emissions regulations.

Industry position

The nickel industry is undertaking a comprehensive environmental research program to address these data gaps. An expert panel, comprising industry-sponsored scientific experts and representatives of EU regulatory bodies, has been engaged to oversee the research program, which is due for completion at the end of 2004. However, the EU is pressing to complete the nickel risk assessment at the end of 2003.
The industry believes that it is essential to complete the environmental data collection before any sound scientific conclusions on risk or no risk can be made. It further believes that the scientific integrity of the EU risk assessment process should not be compromised for the sake of administrative expediency.

Footnotes:

1. PEC - Predicted Environmental Concentration: estimated environmental concentration based on either measured or calculated data.

2. PNEC - Predicted No Effect Concentration: environmental concentration which is regarded as the level below which the balance of probability is that an unacceptable effect will occur.

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