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Universität Heidelberg (2014)

Local assessment of water and sediment quality as prerequisite for integrated water management strategies in Jordan

Förster, Franziska

Titre : Local assessment of water and sediment quality as prerequisite for integrated water management strategies in Jordan

Auteur : Förster, Franziska

Université de soutenance : Universität Heidelberg

Grade : Doctor of Philosophy (PhD) 2014

In order to clarify questions related to adequate and sustainable water management strategies in Jordan, the present thesis was initiated as an interdisciplinary project under the superordinate topic “Water in sensitive regions – Handling limited water resources in sensitive regions of the Near East” within the scope of the corporate project “Global Change and Globalization” of Heidelberg University within the scope of the Excellence Initiative II of the German Research Foundation, which was then integrated into the Heidelberg Center for the Environment. The objective of this dissertation was to elucidate the ecotoxicological hazard and risk of the main Jordanian surface waters (Jordan River, King Abdullah Canal, Yarmouk River, Wadi Mujib, Zarqa River) based on sediment (eco)toxicity assessment of a total of 20 sampling sites. To the best of knowledge, this study is the first to apply ecotoxicological bioassays to address water quality in terms of surface water sediment contamination in Jordan. The in vitro test battery included (a) general toxicity (cytotoxicity in the neutral red assay with RTL-W1 cells), (b) geno-toxicity (DNA damage to RTL-W1 and V79 cells), (c) embryo toxicity (Danio rerio), and (d) dioxin-like activity (EROD assay with RTL-W1 cells), all of which were conducted with acetonic Soxhlet extracts of sediments. It was complemented by assessment of geomorphological parameters and measurement of nutrients and salts. The result of the in vitro bioassays document that sediments from all surface waters were differentially polluted by contaminants that induced mainly genotoxic effects, but also cytotoxicity, embryo toxicity and elevated dioxin-like toxicity. Toxic potentials of the extracts were generally higher in the neutral red assay than in the fish embryo toxicity test. In most sediment samples, the comet assay proved to be more sensitive ; however, for four sampling sites, the micronucleus showed stronger effects. The recently developed test design of a novel EROD assay including the use of β-naphthoflavone as a reference substance and the normalization of EROD activity against MTT reduction proved to be a most promising alternative to conventional protein-based normalization in EROD determination. Based on the differential results, a stepwise processing of toxicity assessment cannot be recommended, since a relationship between the different bioassays for toxicity assessment in terms of “if-then” or “if not-then not” could not be established in this study. For the comprehensive classification of Jordanian surface waters, the results were rated according to toxicity threshold values based on a fuzzy logic-classification approach or according to a rank-sum based classification, resulting in three generalized toxicity levels. The bioassays were also rated according to ecological relevance, and the results were transferred into quality classes in accordance with the EU Water Framework Directive 2000/60/EC. Although results for the single rivers led to a heterogeneous pollution scenario, contamination hot spots could clearly be identified. In conclusion, the northern part of the Jordan River at Baqura, the outlet of Mujib Dam, the outlet of the Unity Dam of the Yarmouk River and the outlet of the wastewater treatment plant Khirbet As Samra discharging into the Zarqa River showed strong to moderate effects in at least four of the five tests applied and were thus rated quality class V indicating very high contamination. Results imply that sewage water treatment is not yet sufficient, particularly regarding mutagenic and dioxin-like compounds, and that non-point sources add to the overall pollution situation. Since the results of this study suggested a certain discrepancy between conventional routine monitoring programs conducted by local authorities, which assign an overall good water quality to Jordanian surface waters, it is strongly recommend to include sediment toxicity assessment and effect-driven specific chemical analyses into regular monitoring programs and considerations for integrated water management.


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