| 摘要: |
| 【 目的】研究环境相关浓度二氯乙酸（DCAA）和三氯乙酸（TCAA）慢性暴露对生菜光合特性及食用 安全的影响，为评估氯乙酸类消毒副产物（DBPs）在农业生产中的潜在风险提供理论依据。【 方法】以散叶生菜为试 验材料，采用土培方法，用不同质量浓度（10，40，70和100 μg/L）DCAA和TCAA的水溶液灌溉35 d，测定不同处理下 生菜生长特性和光合生理特性，并对生菜中DCAA和TCAA的富集系数（BCF）、转运系数（TF）及生菜食用健康风险 进行评估。【 结果】DCAA和TCAA（10，40，70和100 μg/L）组生菜叶片鲜质量分别较对照极显著下降了23.13%-41.64%和10.00%-28.00%，但株高与叶面积无显著变化。DCAA（70和100 μg/L）组生菜根系鲜质量、总根表面积 、平均根系直径及总根体积分别较对照显著下降70.66%-73.88%，46.52%-69.70%，24.14%-26.37%和67.79%-78.85%，且降低程度普遍高于TCAA处理组（66.38%-66.81%，54.75%-55.78%，13.36%-16.44%和64.42%-64.90%），10 μg/L DCAA组生菜根系鲜质量显著下降 28.69%，而10 μg/L TCAA组根系鲜质量无显著性变化 。 TCAA（4070和100 μg/L）组生菜净光合速率（Pn）和胞间CO2浓度（Ci）均显著降低45.08%-63.19%和13.00%-27.68%，且下降幅度均高于DCAA处理组（30.10%-39.09%和11.49%-18.52%）。污染物富集及转移特征显示，DCAA和TCAA在生菜体内的积累具有阈值效应，在70 μg/L灌溉组中BCF和TF出现峰值。生菜食用风险系数随着DCAA和TCAA灌溉浓度的增加而上升，但均小于1。【 结论】环境相关浓度DCAA慢性暴露对生菜根系 形态的损伤较为突出，而TCAA则表现出更强的光合毒性。DCAA和TCAA的风险系数虽未超标，但生菜光合能力下降与根系结构损伤表明，其慢性暴露（≥40 μg/L）将显著影响生菜生理功能及产量。 |
| 关键词: 二氯乙酸 三氯乙酸 生菜 光合生理 |
| DOI：10. 13207/j. jnwafu. 2026. 08. 013 |
| 分类号: |
| 基金项目:福建省科技计划项目（2021Y0041）；厦门市自然科学基金项目（3502Z202573074） |
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| Effects of chloroacetic acid⁃based disinfection by⁃products on photosynthetic characteristics and food safety of lettuce |
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YE Fan1, CHEN Guoyuan1,2, JIANG Zihan1, LI Qingsong1,2
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1.School of Environmental Science and Engineering，Xiamen University of Technology，Xiamen，Fujian 361024，China;2.The Key Laboratory of Water Resources Utilization and Protection of Xiamen，Xiamen，Fujian 361024，China
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| Abstract: |
| 【 Objective】This research aims to investigate the effects of chronic exposure of lettuce（Lactuca sativa） to environmentally relevant concentrations of dichloroacetic acid （DCAA） and trichloroacetic acid （TCAA） on its photosynthetic characteristics and consumption safety，to provide a theoretical basis for evaluat?ing the potential risks of chloroacetic acid-based disinfection byproducts （DBPs） in irrigated agriculture.【Method】Using loose-leaf lettuce as the test materials，a soil culture experiment was conducted. Irrigation was performed for 35 days with aqueous solutions of DCAA and TCAA at different mass concentrations（10，40，70 and 100 μg/L）. The growth characteristics and photosynthetic physiological properties of lettuce were determined under different treatments，and the bioconcentration factor（BCF），transport factors（TF），and health risks of consuming lettuce of DCAA and TCAA in lettuce were also analyzed.【Result】Compared with the control group，in both the DCAA and TCAA（10，40，70 and 100 μg/L） groups，the fresh mass of lettuce leaves de-creased significantly by 23.13%-41.46% and 10.00%-28.00%，respectively，but there was no significant difference in the height and leaf area of the plant. In DCAA（70 and 100 μg/L） groups，the fresh root mass，the total surface area of the roots，average root diameter and total root volume were significantly decreased by 70.66%-73.88%，46.52%-69.70%，24.14%-26.37% and 67.79%-78.85%，respectively，which were generally higher than those in the TCAA treatment group（66.38%-66.81%，54.75%-55.78%，13.36%-16.44%，and 64.42%-64.90%）. Under 10 μg/L DCAA treatment，the root fresh mass of lettuce was sig?nificantly decreased by 28.69%. Under 10 μg/L TCAA treatment，no significant difference was observed in the root fresh mass. In contrast，the net photosynthetic rate（Pn） and intercellular CO2 concentration（Ci） of lettuce were significantly reduced by 45.08%-63.19% and 13.00%-27.68% in the TCAA（40，70，and 100 μg/L） group，which were higher than those in the DCAA treatment group（30.10%-39.09% and 11.49%-18.52%）. The enrichment and transfer characteristics of the pollutants showed that the accumulation of DCAA and TCAA in lettuce had a threshold effect，and the peak values of BCF and TF were observed in the 70 μg/L irrigation group. The risk index（RI） of lettuce consumption increased with the increase of DCAA and TCAA irrigation concentration，but remained lower than 1 in both cases.【Conclusion】The damage to lettuce root morphology by chronic exposure to environmentally relevant concentration of DCAA was prominent，whereas TCAA showed stronger photosynthesis toxicity. Although the risk index for DCAA and TCAA did not exceed the threshold，the reduced photosynthetic capacity and root structure damage in lettuce indicate that chronic exposure（≥40 μg/L） will significantly impair the plant’s physiological functions and yield. |
| Key words: dichloroacetic acid trichloroacetic acid lettuce photosynthetic physiology |
