By Erik Hagen
This English translation was published 24 March 2010.
AngloGold Ashanti, in which the Norwegian Government Pension Fund – Global has invested about a half billion Norwegian kroner, has commissioned an investigation into the toxicity levels around its gold mine in Tanzania.
The mining company commissioned the investigation from the British consultancy firm SRK shortly after Norwatch’s article in 2008 on the indigenous population’s complaints about serious health problems.
The results, which were ready before the New Year, “suggest that there are no substantive causes for concern regarding impacts on soil and agricultural products” in the area around the mine.
The Norwegian researcher Åsgeir Almås at the Norwegian University of Life Sciences is nevertheless critical of the company’s analyses, which found hardly any harmful metals at all. Almås has read the report and calls the geologic insight inadequate and the methodological approach deficient.
Almås himself carried out analyses in the same area, on commission from Norwegian Church Aid. Whereas the Norwegian study examined sediments and water, the company report investigated the toxicity level in soil and plants. Almås believes this constitutes a great weakness.
“The troublesome findings are in the sediments,” Almås explained.
Normally it takes a long time from a leak has occurred until it can be demonstrated in soil. In sediments at the bottom of puddles, dams and rivers, however, deposits are more concentrated and more obviously layered. This makes it easier to demonstrate changes over time. Thus, even though the company’s analyses could be suitable for examining what the population consumes by means of plants, they will not, according to Almås, reveal any possible episodes of pollution.
The researcher also claimed that there are several other methodological weaknesses in how the company’s consultants gathered the soil samples. They took samples from the top 15 cm of the soil and defended this by that cultivated land is turned during ploughing and that one must therefore take samples far down in the soil. Almås explained that this can be a useful approach when analysing soil quality for crop production, but to take a 15-cm sample is far too much.
“It is not an especially good method for demonstrating possible pollution. If there had been episodes of pollution, they would lie in the top couple of centimetres. When one takes a 15-cm sample, all the analysis results would automatically be diluted,” Almås said.
He explained that the Norwegian study examined at maximum the top 5 cm and that this may partly explain why all the concentrations in the company’s report are 5%-50% lower than those in the Norwegian analyses.
The most important weakness, according to Almås, is nevertheless the inadequate methodological description (point 3.3 in the report). He pointed out that the company’s study did not, among other things, use standard reference soil, which is a soil sample that has already been analysed in many laboratories internationally and which can be purchased when carrying out one’s own laboratory analyses. Such reference material makes it possible to double-check whether the laboratory analyses carried out are correct. Any possible laboratory errors may be ascertained by means of reference soil.
The Norwegian study used both reference soil and reference water.
“The combination of an inadequate methodological chapter and the lack of standard reference material entails that the report does not maintain a good scientific standard. It is quite simply difficult to evaluate or check their figures. The investigation is not good enough to take the area off the sick list,” Almås said.
Confidence in the Results
The company itself is nonetheless confident about its results. “The method used by SRK is presumed to be proper for a screening study, and our Tanzanian partners vouched for it.”
The company confirmed that it did not use reference soils, but it is “confident that the quality control processes used during the project and analysis were acceptable” and has “confidence in the results produced by the laboratory”.
The company has not decided yet whether they will pursue the analysis of the sediments further.
“We are currently considering how to best proceed with further investigations and which areas to focus upon. We would prefer further work in the area to be based on sound scientific methodologies and a collaborative initiative and that includes the local government, community and academic institutions”, Fine wrote.
Fine also urged the Norwegian researcher to indicate to the company on exactly which points he believes the methods in the company’s report may possibly be inadequate.
“It is still unclear what the critique regarding SRK’s methodology in Chapter 3 is, and we recommend that Mr. Almås put these in writing so that we can ask SRK to respond, or clarify any technicalities that might not have been recorded in the final report.
In the course of the past year the Pension Fund partly divested itself of the Tanzanian mining company, from 889 to 479 million kroner.