Consequences of increased content of hexavalent chromium in cement – Part 1 When new structures are erected. Based on typical cases and data from leaching tests which represent “worst case” scenarios the following conclusions of the influence of an increase in Cr(VI) content of a cement from 2 ppm to 9 ppm has been drawn. More care must be devoted to protecting persons from contact with the fresh concrete than normally. In drinking water plants there is no risk for jeopardizing the long-term water quality. However, the Cr(VI) content in the water may exceed the required maximum level during an initial period after construction of the plant, during which the Cr-content must be controlled before the water is delivered. Whether special measures need to be taken for a specific project depends on how high the Cr(VI) content was in the cement and in how big part of the facility it has been used. If the water exposure (water retention time×concrete surface area/water volume) on these parts is less than a fourth of the exposure of the total facility, no special measures need to be taken. For new concrete structures in free water the yearly average for Cr-content in the water shall not be influenced more than marginally. In stationary water this criterion is fulfilled if every m² of concrete surface is surrounded by around 6 m³ water. In streaming water, like in rivers, the demand on necessary water volume is decreased. When underwater casting is used the necessary water volume per m² concrete surface exposed to water during casting should be raised to 10 m³. A concrete structure in contact with ground water will not influence the ground water so that it will not be possible to drink or pollute the soil so that its use is restricted at most locations in Sweden. In places with particularly high background levels of chromium in the water or in the ground, a more detail risk assessment should be to be carried out.
Elisabeth Helsing (Wed,) studied this question.