Remediation of sites contaminated with 90Sr and 137Cs: radiological protection of non-human biota

When remediating sites contaminated with manmade radionuclides, one should be assured that established remediation criteria would ensure radiological protection both of members of the public and of biological systems. The purpose of the study was to estimate levels of radiation safety of non-human biota in remediated sites, contaminated with 90Sr and 137Cs, for various scenarios of the remediated land use. Six possible scenarios for remediated areas use were considered. For the assessment of doses to the critical group of the public in the scenarios data published in the UK National Radiological Protection Board (NRPB-W36) were used. For estimating doses to non-human biota dose coefficients for external and internal exposure available in the ICRP 136 Publication were used. As calculated, in some scenarios for the use of remediated sites previously contaminated with 90Sr, or 90Sr and 137Cs, if remediation criterion (reference level) for the critical group of the public was 1 mSv/year the criteria of permissible radiation exposure to biological systems may be exceeded. In some scenarios criteria below 1 mSv/year should be used to ensure radiation safety of biological systems. As calculated, if in some scenarios for the use of remediated sites, previously contaminated with 90Sr or with 90Sr and 137Cs, the remediation criterion for critical group of the public is taken as 1mSv/year, reference levels of permissible radiation dose to non-human biota may be exceeded. To ensure radiological protection of the biota species in remediated sites, in some scenarios for these sites use, the remediated criteria should be below 1 mSv/year.