Rijkswaterstaat made calculation error in controversial granulite project

Rijkswaterstaat made a calculation error when calculating the risks of dumping granulite in a natural pond in the municipality of West Maas and Waal. That is what experts say to the television programme Zembla. The programme’s calculations are confirmed by the environmental department of the municipality of West Maas and Waal, in the Gelderse Rivierengebied.

Rijkswaterstaat acknowledges that an error was made, but it was said to be an error on paper.

Earlier this year, Zembla reported that the top of Rijkswaterstaat had granted a permit to deposit 750,000 tons of granulite in the natural lake, despite strong objections from lower civil servants.

According to the programme, 72,000 kilos of the toxic substance acrylamide could end up in the water in the worst case scenario. Acrylamide can be released from granulite and is a residual product that is produced during the crushing, washing and sieving of granite blocks.

The municipality of West Maas and Waal tried to end the dumping of granulite with a court case in recent months, but was wrong. The judges based their verdict partly on the calculation of Rijkswaterstaat.

A thousand times higher

Rijkswaterstaat calculated how many milligrams of acrylamide would end up in the puddle per litre in the worst-case scenario. According to Zembla, the memo about this was written on 3 June of this year, more than seven months after the landfill was approved. The memo states that 0.0078 milligram (mg) acrylamide per litre would end up in the water, far below the limit of 2.04 mg per litre.

Zembla now reports that the actual value is a thousand times higher, at 7.78 mg per litre. This is confirmed by the environmental service of the municipality of West Maas and Waal, says a spokesman for the municipality. After Zembla’s findings, the municipality itself also had calculations carried out and came to the same conclusions as BNNVARA’s research programme.

Rijkswaterstaat: dust does not occur in practice

According to the Directorate-General for Public Works and Water Management, there has indeed been a miscalculation on paper, but a spokesman of the agency says that the miscalculation “does not alter the conclusion that in practice acrylamide does not occur in the granulite that is deposited in the puddle”.

“There is therefore no question of exceeding standards or a risk to people and the environment,” reports a spokesman. “Several investigations and samples have already shown that. In order to remove the unrest in the neighbourhood, all known information will be tested again.”

According to Rijkswaterstaat, both the values of 2.04 mg per litre, where the limit lies, and the 7.8 mg per litre are unrealistic for the project in the municipality of West Maas and Waal. The authority says it regrets the error. “This shouldn’t have happened.”