Abstract

The radiation dose for the Dutch population due to discharges and emissions from processing industries has decreased substantially since 1994. However, the processing industry still makes the largest industrial contribution to the radiation dose. Nuclear installations and medical institutions contribute much less. There was a considerable decrease up to 2000, when two fertilizer enterprises stopped their activities in the Netherlands. Although the reported discharges of radioactive substances to water show a sharp decrease, the collective dose due to emissions to air has shown slight increases since 2001. The policy to reduce discharges in water has led to enterprises investing in wastewater treatment systems. Enterprises also take the radiological consequences into account when purchasing raw materials containing natural occurring radioactive material. The cost of the raw material obviously also influences the decision. Occupational exposure in processing plants was investigated using the data of the National Dose Registration and Information System (NDRIS). Often, employees' inhalation doses can amount to over 1 mSv per annum (i.e. 40% of the average annual radiation dose per capita of the Dutch population), but the dose limit of 6 mSv was not exceeded in any of the cases. We have developed and applied the chain model for regular emissions for assessing the radiation dose. Current dose assessments based on the chain model were found to fit with dose assessments based on measurements. The yearly variation in meteorological factors can affect the radiation dose for members of the public for 25% at locations close to the source when compared to calculations based on decennium averaged meteorology.