Root uptake by cultivated vegetables of radionuclides coming from contaminated algae used as organic manure in soil

¹ IPSN/DPRE/SERLAB/LRE, CE Cadarache, 13108 Saint-Paul-lez-Durance, France
² IPSN/DPRE/SERNAT/LERFA, BP. 10, 50130 Cherbourg-Octeville, France

Abstract

In certain areas of the French Atlantic coast, algae of marine origin are used as organic fertilizer, particularly for vegetables cultivation. An experiment was carried out to estimate the transfers of radioactivity towards agricultural productions, which could result from this practice in the case where algae were contaminated. Algae (fucus vesiculosus) were cultivated in aquarium with seawater containing a mixture of radionucléides : ²²Na, ⁶⁰Co, ⁹⁰Sr, ⁹⁹Tc, ¹⁰⁶Ru, ¹²⁵Sb, ^{134, 137}Cs, ^{238, 239+240}Pu, ²⁴¹Am, ²⁴⁴Cm. These algae were mixed, in a lysimeter, with a silty-sandy soil. Some vegetables, potatoes, lettuces, radishes, beans, tomatoes were cultivated on this manured soil. The soil to plant concentration ratios are given for the edible organs of the plants grown the year following the addition of algae in the soil and for cultures made several years later. On the other hand chemical extractions were performed to evaluate the bioavailable fraction of radionuclides in the soil.