Radionuclide transfer to vegetables: comparison furrows and sprinkler irrigations

The use of irrigation in arid agriculture, while essential for food security, can introduce radionuclides into the food chain if water sources are contaminated. Current radioecological models for arid and semi-arid nuclear facilities lack region-specific data, particularly for the critical exposure pathway of irrigation. This study investigated the transfer of key radionuclides (⁵⁹Fe, ⁶⁰Co, ⁶⁵Zn, ⁸⁹Sr, ¹⁰⁶Ru, ¹³⁴Cs, ¹⁴⁴Ce) to staple vegetable crops - including tomatoes, cucumbers, carrots, and potatoes - under furrow irrigation in Russia's North Caucasus region. Results demonstrate that radionuclide accumulation is highly dependent on the element, crop species, and plant organ. ⁶⁵Zn and ⁸⁹Sr consistently showed the highest mobility, whereas ¹⁰⁶Ru and ¹⁴⁴Ce showed the lowest accumulation. A comparison of furrow and sprinkler irrigation methods demonstrated that irrigation technique is a decisive factor in radionuclide entry into the food chain. Compared to furrow irrigation, sprinkler systems increased aggregated transfer factors for crop biomass by 6-40 times and by 2-9 times for edible parts. Furthermore, irrigation enhanced the vertical migration of radionuclides in the soil profile by approximately 3 cm, thereby increasing their long-term radionuclides bioavailability. This work establishes that irrigation technique is a decisive factor in radionuclide entry into the food chain. The findings provide essential quantitative data for improving safety assessments, environmental impact models, and agricultural management strategies in arid regions with nuclear activities or radionuclide contamination.