This document contains data on mercury concerning the sources and distribution, and the risks based exposure levels and hazardous concentrations. The autonomous developments in the emissions are also described and an insight is given into any possible technical measures for further emission control. Mercury is one of the heavy metals. In the Netherlands mercury is obtained as a byproduct (several tonnes) in the natural gas extraction and the primary zinc production. In 1990 its use amounted to 13 tonnes, 40% of which was applied as amalgam in dentistry, 20% in batteries and 40% in measuring equipment, incandescent lamps and in the chloralkali industry. An amount of approximately 40 tonnes of mercury is landfilled annually with waste (based on 1990 data). A major cause of the relatively high amount of mercury waste is the non-intentional mercury flow: mercury as an unintended byproduct in various base materials. This non-intentional flow is responsible for more than 50% of the mercury occurring in waste. The emission to air amounted to approximately 4 tonnes (particularly from waste incineration and the chloralkali industry), to water amounted to approximately 1 tonne (especially from the phosphorous fertilizer industry and dentistry), to the soil to approximately 1.2 tonne (especially by application of fertilizer on agricultural land). The contribution to the mercury load from abroad is considerable. For surface water this is estimated at 75% (based on 1990 data). The deposition is also mainly determined by the background level and thus constitutes the major load of the soil in the Netherlands.