Destructive effect of UV-C light radiation on lettuce growth: risk assessment of long time exposure

Ultraviolet C (UV-C) light technology employs a particular wavelength within the ultraviolet spectrum to deactivate microorganisms, utilizing radiation as its method. UV-C light possesses germicidal properties, effectively disrupting the DNA of microorganisms such as bacteria, viruses and various pathogens, thereby impeding their ability to replicate and induce illness. Additionally, UV-C could enhance the production of phytochemicals and prevent contamination in agricultural applications. However, overexposure to UV-C can cause safety issues, especially for operators handling its utilization in germicidal or sterilization applications. This study investigated the destructive effects of UV-C light on the morphology and chlorophyll content of lettuces exposed to various durations, aiming to assess the risks associated with prolonged exposure. The results showed that prolonged UV-C exposure affects morphological and chlorophyll content changes. The most damaging effect on lettuce morphology and chlorophyll content was found in the 2 h of UV-C exposure treatment. In the 2 h of UV-C exposure treatment, lettuce length was reduced from 6.01 ± 0.80 cm on day 2 to 5.55 ± 0.78 cm on day 3. The lowest fresh weight of lettuce was also found at 2 h of UV-C exposure treatment (4.32 ± 0.94 gr). In addition, the lowest total lettuce stomata aperture was found in 2 h of UV-C treatment (41 units). Furthermore, on day 4, after 2 h of UV-C exposure treatments, the chlorophyll a, chlorophyll b and total chlorophyll content in lettuces were found to be 1.59 ± 0.02 mg g−1 FW, 0.93 ± 0.02 mg g−1 FW and 2.52 ± 0.04 mg g−1 FW, respectively. Therefore, the most destructive effect of UV-C was found during 2 h of UV-C exposure treatment. These findings indicate the dangers of long-term UV-C exposure to lettuce. Practically, this could also have a negative impact on humans. The knowledge gleaned from these findings is useful for safety issues in the industrial application of UV-C.