Boukhellout Salah, Taïbi Khaled, Aït Abderrahim Leila, Khallef Messaouda
Laboratory of Molecular and Cell Biology, Faculty of Life and Natural Sciences, Department of Biology, Ibn Khaldoun University of Tiaret, 14000, Tiaret, Algeria.
Laboratory of Biochemistry and Applied Toxicology, Faculty of Life and Natural Sciences, and Earth and Universe Sciences, Department of Biology, University May 8th 1945 of Guelma, 24000, Guelma, Algeria.
Environ Monit Assess. 2025 Jun 4;197(7):726. doi: 10.1007/s10661-025-14163-7.
The growing global water crisis, intensified by both declining water supplies and deteriorating quality, poses acute challenges in semi-arid regions where contaminated water reuse threatens ecosystems and food security. The present study evaluates the cytotoxic and genotoxic risks of wastewater in the Tiaret region, Algeria, integrating quality of water sources to trace pollutants impacts from untreated municipal discharge to agricultural irrigation using the Allium cepa bioassay. Water samples were collected from strategic points across seasons (2023), including untreated wastewater (WW), treated wastewater (TW), Oued Nahr-Ouassel water (OW), Dahmouni dam water (DW), and irrigation water (IW) and were analyzed for organic load, nutrients, suspended solids, and ionic strength. Cytogenetic parameters were assessed via root growth inhibition, mitotic index, and chromosomal aberrations. Results revealed significant cytotoxicity and genotoxicity, with WW (high organic pollution with Biochemical Oxygen Demand, BOD₅: 267.5 ± 37.5 mg/L; Chemical Oxygen Demand, COD: 562 ± 33.9 mg/L) exhibiting severe root growth inhibition (62-72% reduction), co-occurred with elevated mitotic indices (26.96-27.9%) and chromosomal aberrations (19.64%), due to metaphase arrest rather than productive proliferation, resolving the paradox of high mitotic indices alongside growth suppression. Genotoxicity was categorized as high (≥ 15% aberrations) in WW, moderate (5-15%) in TW, OW and DW, and low (< 5%) in IW, with seasonal peaks in genotoxicity occurred in winter WW (19.6% aberrations) and summer OW (14.2%), highlighting concerns over incomplete removal of pollutants during wastewater treatment and its implication for persistent environmental and public health risks. Although partial treatment reduced genotoxicity by 23-42%, yet TW still induced metaphase arrest and micronuclei. These findings underscore the limitations of conventional treatment in mitigating pollution-driven DNA damage amplified by synergistic physicochemical stressors and provide critical insights into the implications for agricultural safety and public health. This study emphasizes the urgent needs for adaptive water management and stringent regulatory measures in semi-arid regions reliant on contaminated water for human uses and agriculture.
全球水危机日益严重，水资源供应减少和水质恶化加剧了这一危机，在半干旱地区构成了严峻挑战，因为污水回用威胁着生态系统和粮食安全。本研究利用洋葱生物测定法，评估了阿尔及利亚提亚雷特地区废水的细胞毒性和遗传毒性风险，综合考虑水源质量，以追踪从未经处理的城市污水排放到农业灌溉过程中污染物的影响。在2023年四季从战略要点采集了水样，包括未经处理的废水（WW）、处理后的废水（TW）、瓦迪纳赫尔-瓦塞尔水（OW）、达穆尼大坝水（DW）和灌溉水（IW），并对有机负荷、营养物质、悬浮固体和离子强度进行了分析。通过根生长抑制、有丝分裂指数和染色体畸变评估细胞遗传学参数。结果显示出显著的细胞毒性和遗传毒性，未经处理的废水（有机污染严重，生化需氧量BOD₅：267.5±37.5毫克/升；化学需氧量COD：562±33.9毫克/升）表现出严重的根生长抑制（减少62 - 72%），同时有丝分裂指数升高（26.96 - 27.9%）和染色体畸变（19.64%），这是由于中期停滞而非有效增殖所致，解决了高有丝分裂指数与生长抑制并存的矛盾。未经处理的废水遗传毒性被归类为高（≥15%畸变），处理后的废水、OW和DW为中度（5 - 15%），灌溉水为低（<5%），遗传毒性的季节性峰值出现在冬季的未经处理废水（19.6%畸变）和夏季的OW（14.2%），凸显了对废水处理过程中污染物去除不完全及其对持续环境和公众健康风险影响的担忧。虽然部分处理使遗传毒性降低了23 - 42%，但处理后的废水仍会诱导中期停滞和微核形成。这些发现强调了传统处理在减轻由协同物理化学应激源放大的污染驱动的DNA损伤方面的局限性，并为农业安全和公众健康的影响提供了关键见解。本研究强调了在依赖受污染水用于人类用途和农业的半干旱地区，迫切需要适应性水资源管理和严格的监管措施。
