Remediation activities in polluted sediments, such as dredging and capping, induce the risk of transporting polluted sediments into the water column. Turbidity surveillance is the common method for in situ environmental monitoring during such activities. However, at various stages of the remediation process, the turbidity may be caused by either clean or polluted materials. Here, the potential of using chemical sensors to discriminate between turbidity caused by clean and polluted sediments is evaluated. Dissolved oxygen (DO), turbidity and pH were measured in laboratory tests with suspensions of three different polluted sediments, as well as for two common clean capping materials. Additionally, turbidity, pH and DO were measured during dredging at one of the polluted sites. While turbidity caused by clean materials did not affect pH or DO, there was an inverse linear relationship between DO and turbidity for two of the polluted sediments. Furthermore, for two of the sediments, pH was a strong indicator of sediment resuspension into the water column, with ΔpH > 0.5 both in the lab and during dredging in the field. Hence, pH and/or DO surveillance showed to be a potential tool for in situ real-time monitoring of environmental risk during disturbances in polluted sediments.

中文翻译：

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污染沉积物扰动期间pH值和溶解氧的实时监测

受污染沉积物的修复活动，例如疏浚和封盖，会导致受污染沉积物进入水体的风险。浊度监测是此类活动中原位环境监测的常用方法。然而，在修复过程的各个阶段，浑浊可能是由清洁材料或污染材料引起的。在这里，评估了使用化学传感器区分清洁沉积物和污染沉积物引起的浑浊度的潜力。在实验室测试中，使用三种不同污染沉积物的悬浮液以及两种常见的清洁覆盖材料测量了溶解氧 (DO)、浊度和 pH 值。此外，在一处污染地点的疏浚过程中测量了浊度、pH 值和溶解氧。虽然清洁材料引起的浑浊不会影响 pH 值或 DO，两种污染沉积物的溶解氧和浊度之间存在反线性关系。此外，对于其中两种沉积物，pH 值是沉积物重新悬浮到水柱中的有力指标，在实验室和现场疏浚过程中，ΔpH > 0.5。因此，pH 和/或 DO 监测被证明是污染沉积物扰动期间环境风险原位实时监测的潜在工具。