ABSTRACT One of the methods of sludge disposal in cities is its use as an amendment in adjoining agricultural soil. Contaminants in sludge can, however, nullify the benefits. Polycyclic aromatic hydrocarbons (PAHs) are a class of persistent organic pollutants, if present, can pose health risks by virtue of their carcinogenic potential and persistence in soil. The present study deals with profile analysis of PAHs in digested sewage sludge of a megacity, Delhi. Mean concentration of the sum of 16 PAHs in the sludge from 5 sewage treatment plants (STPs) was 20.67 ± 4.14 mg/kg, dry weight (dw). Carcinogenic PAHs represented ∼47% of the total PAHs. Benzo[g,h,i]perylene recorded the highest mean concentration followed by dibenzo[a,h]anthracene. Low molecular weight PAHs and high molecular weight PAHs contributed 19% and 81% to total PAHs content respectively. Principal component analysis identified the major sources of PAHs in sludge as coal and natural gas combustion. Wood combustion, oil and oil derivatives are the other identified sources. The observed PAH levels in sludge from selected STPs of Delhi were found to violate the limit values proposed by the European Union and the US legislation for application in agriculture. GRAPHICAL ABSTRACT

中文翻译：

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消化污水污泥中的多环芳烃 (PAH) 概况。

摘要 城市污泥处理的方法之一是将其用作毗邻农业土壤的改良剂。然而，污泥中的污染物会抵消这些好处。多环芳烃 (PAH) 是一类持久性有机污染物，如果存在，由于其致癌潜力和在土壤中的持久性，可能会对健康构成威胁。本研究涉及德里大城市消化污泥中多环芳烃的分布分析。来自 5 个污水处理厂 (STP) 的污泥中 16 种多环芳烃总和的平均浓度为 20.67 ± 4.14 mg/kg，干重 (dw)。致癌性多环芳烃占总多环芳烃的约 47%。苯并[g,h,i] 苝的平均浓度最高，其次是二苯并[a,h] 蒽。低分子量多环芳烃和高分子量多环芳烃分别占多环芳烃总含量的 19% 和 81%。主成分分析确定了污泥中多环芳烃的主要来源是煤和天然气燃烧。木材燃烧、石油和石油衍生物是其他已确定的来源。发现在德里选定的 STP 污泥中观察到的 PAH 水平违反了欧盟和美国农业应用立法提出的限值。图形概要 发现在德里选定的 STP 污泥中观察到的 PAH 水平违反了欧盟和美国农业应用立法提出的限值。图形概要 发现在德里选定的 STP 污泥中观察到的 PAH 水平违反了欧盟和美国农业应用立法提出的限值。图形概要