Abstract The use of reclaimed water for irrigation after disinfection can provide significant environmental, social and economic benefits and solve the problem of water scarcity. The occurrence of disinfection by-products (DBPs) as pollutants in irrigation water has been highlighted as a health risk of emerging concern since they can be uptaken by the plant and accumulated in the edible parts during crop production. Little attention has been paid to the occurrence of chlorate in reclaimed water when using chlorine as a tertiary disinfection treatment. This study aimed at evaluating if chlorine-treated reclaimed water from a Municipal Wastewater Treatment Plant resulted in the accumulation of chlorate in commercially grown romaine lettuce. The risk of accumulation in the edible parts of the head was also examined by comparing the internal, middle, and external leaves as well as the roots. The results showed that the irrigation with chlorinated reclaimed water resulted in the accumulation of chlorate in fresh lettuce (0.34–0.56 mg kg−1), despite that the chlorate content in irrigation water was below the maximum residual level (MRL) allowed for potable water (0.25–0.49 vs. 0.70 mg L−1, respectively). The chlorate content gradually increased from the inner leaves (younger) (0.21 mg kg−1) to the outer leaves (oldest) (0.55 mg kg−1), and the roots (0.56 mg kg−1). This study shows that there was chlorate bioconcentration observed in fresh lettuce heads, although it did not exceed the current maximum residue levels for chlorate on leafy greens (0.7 mg kg−1) established in the amended Regulation (EC) No 396/2005 (SANTE/10684/2015 Rev. 9) recently adopted. However, the use of chlorate-free disinfectants as antimicrobial agents for the irrigation of edible crops with a low level antimicrobial residual to protect water in distribution systems is recommended to reduce the chlorate intake by consumers.

中文翻译：

---

露天栽培和再生水灌溉的商品生菜中氯酸盐的积累

摘要 将消毒后的再生水用于灌溉，可提供显着的环境、社会和经济效益，解决水资源短缺问题。消毒副产物 (DBP) 作为灌溉水中的污染物，已被强调为新出现的健康风险，因为它们可以被植物吸收并在作物生产过程中积累在可食用部分。使用氯作为三级消毒处理时，很少注意再生水中氯酸盐的出现。本研究旨在评估来自城市污水处理厂的氯处理再生水是否会导致商业种植的长叶莴苣中氯酸盐的积累。还通过比较内部、中部、和外部叶子以及根。结果表明，尽管灌溉水中的氯酸盐含量低于饮用水允许的最大残留水平 (MRL)，但使用氯化再生水灌溉导致新鲜生菜中氯酸盐的积累 (0.34–0.56 mg kg-1) （分别为 0.25–0.49 与 0.70 mg L-1）。氯酸盐含量从内叶（年轻）（0.21 mg kg-1）到外叶（最老）（0.55 mg kg-1）和根（0.56 mg kg-1）逐渐增加。该研究表明，在新鲜生菜头中观察到氯酸盐生物富集，尽管它没有超过经修订的 (EC) No 396/2005 (SANTE) 规定的绿叶蔬菜上氯酸盐的当前最大残留水平 (0.7 mg kg-1) /10684/2015 Rev. 9) 最近通过。然而，