Institute of Environmental Science & Research Ltd (ESR), PO Box 29181, Christchurch 8540, New Zealand.
Institute of Environmental Science & Research Ltd (ESR), PO Box 29181, Christchurch 8540, New Zealand.
Sci Total Environ. 2017 Aug 15;592:144-152. doi: 10.1016/j.scitotenv.2017.03.072. Epub 2017 Mar 17.
With the intensification of human activities, fresh water resources are increasingly being exposed to contamination from effluent disposal to land. Thus, there is a greater need to identify the sources and pathways of water contamination to enable the development of better mitigation strategies. To track discharges of domestic effluent into soil and groundwater, 10 synthetic double-stranded DNA (dsDNA) tracers were developed in this study. Laboratory column experiment and field groundwater and soil lysimeter studies were carried out spiking DNA with oxidation-pond domestic effluent. The selected DNA tracers were compared with a non-reactive bromide (Br) tracer with respect to their relative mass recoveries, speeds of travel and dispersions using the method of temporal moments. In intact stony soil and gravel aquifer media, the dsDNA tracers typically showed earlier breakthrough and less dispersion than the Br tracer, and underwent mass reduction. This suggests that the dsDNA tracers were predominantly transported through the network of larger pores or preferential flow paths. Effluent tracking experiments in soil and groundwater demonstrated that the dsDNA tracers were readily detectable in effluent-contaminated soil and groundwater using quantitative polymerase chain reaction. DNA tracer spiked in the effluent at quantities of 36μg was detected in groundwater 37m down-gradient at a concentration 3-orders of magnitude above the detection limit. It is anticipated it could be detected at far greater distances. Our findings suggest that synthetic dsDNA tracers are promising for tracking effluent discharges in soils and groundwater but further studies are needed to investigate DNA-effluent interaction and the impact of subsurface environmental conditions on DNA attenuation. With further validation, synthetic dsDNA tracers, especially when multiple DNA tracers are used concurrently, can be an effective new tool to track effluent discharge in soils and groundwater, providing spatial estimation on the presence or absence of contamination sources and pathways.
随着人类活动的加剧，淡水越来越容易受到污水排放到土地的污染。因此，更需要确定水污染的来源和途径，以便制定更好的缓解策略。为了追踪生活污水排放到土壤和地下水中，本研究开发了 10 种合成双链 DNA（dsDNA）示踪剂。通过用氧化塘生活污水对 DNA 进行标记，进行了实验室柱实验和野外地下水和土壤渗滤器研究。与非反应性溴化物（Br）示踪剂相比，选择的 DNA 示踪剂在相对质量回收率、旅行速度和使用时间矩方法的分散度方面进行了比较。在完整的石质土壤和砾石含水层介质中，dsDNA 示踪剂通常比 Br 示踪剂更早地突破，分散度更低，并且质量减少。这表明 dsDNA 示踪剂主要通过较大孔隙或优先流路径的网络进行传输。在土壤和地下水中的污水跟踪实验表明，使用定量聚合酶链反应可以很容易地在受污水污染的土壤和地下水中检测到 dsDNA 示踪剂。在 37m 下的地下水中，在数量为 36μg 的污水中添加的 DNA 示踪剂被检测到，浓度比检测限高出 3 个数量级。预计可以在更远的距离检测到。我们的研究结果表明，合成 dsDNA 示踪剂在追踪土壤和地下水中的污水排放方面很有前景，但需要进一步研究 DNA-污水相互作用以及地下环境条件对 DNA 衰减的影响。随着进一步的验证，合成 dsDNA 示踪剂，特别是当同时使用多个 DNA 示踪剂时，可以成为追踪土壤和地下水中污水排放的有效新工具，提供对污染来源和途径存在或不存在的空间估计。
