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Comparison of six sewage effluents treated with different treatment technologies-Population level responses in the harpacticoid copepod Nitocra spinipes.
Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
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2010 (English)In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 96, no 4, 298-307 p.Article in journal (Refereed) Published
Abstract [en]

Since conventional treatment technologies may fail in removing many micro-pollutants, there is currently a focus on the potential of additional treatment technologies for improved sewage treatment. The aim of the present study was to evaluate six different effluents from Henriksdal Sewage Treatment Plant in Stockholm, Sweden. The effluents were; conventionally treated effluent (chemical phosphorous removal in combination with an activated sludge process, including biological nitrogen removal and a sand filter), with additional treatments individually added to the conventional treatment; active carbon filtration, ozonation at 5mgl(-1), ozonation at 15mgl(-1), ozonation at 5mgl(-1)+moving bed biofilm reactor and irradiation with ultraviolet radiation+hydrogen peroxide. The evaluation was done by characterizing and comparing the effluents using a Lefkovitch matrix model based on a life cycle test with the harpacticoid copepod Nitocra spinipes, combined with analysis of juvenile development and survival over time. The conventionally treated effluent resulted in the most negative effects, leading to the conclusion that all additional treatments in the present study created effluents with less negative impacts on the copepod populations. The ozone treatments with the low dose treatment in particular, resulted in the overall least negative effects. Moving bed biofilm reactor combined with ozone did not improve the quality of the effluent in the sense that slightly more negative effects on the population abundance were seen for this treatment technology compared to ozonation alone. The active carbon treatment had more negative effects than the ozone treatments, most of which could possibly be explained by removal of essential metal ions. The effluent which was treated with ultraviolet radiation+hydrogen peroxide resulted in few developmental and survival effects over time, but still showed negative effects on the population level. Matrix population modeling proved a useful tool for biologically characterizing and comparing the effluents. Basing the assessment either on the individual level data (development and survival over time or total reproductive output) or the population level data (lambda values and projected population abundances) would not have resulted in the same conclusions as combining both analyses. The juvenile development and survival over time allowed for closer monitoring of the important molting process, whereas the population modeling provided an integrated measure of potential effects at the population level. If the dilution of the effluent in the recipient is considered, the biological effects recorded in the present study were not of substantial significance for the copepod populations, regardless of treatment technology.

Place, publisher, year, edition, pages
2010. Vol. 96, no 4, 298-307 p.
Keyword [en]
Lefkovitch matrix; Characterize; Life cycle test; Sewage treatment
National Category
Natural Sciences
URN: urn:nbn:se:su:diva-34622DOI: 10.1016/j.aquatox.2009.11.011ISI: 000275763900007PubMedID: 20022642OAI: diva2:285300
authorCount :6Available from: 2010-01-11 Created: 2010-01-11 Last updated: 2014-04-08Bibliographically approved
In thesis
1. Population modeling using harpacticoid copepods: Bridging the gap between individual-level effects and protection goals of environmental risk assessment
Open this publication in new window or tab >>Population modeling using harpacticoid copepods: Bridging the gap between individual-level effects and protection goals of environmental risk assessment
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

To protect the environment from contaminants, environmental risk assessment (ERA) evaluates the risk of adverse effects to populations, communities and ecosystems. Environmental management decisions rely on ERAs, which commonly are based on a few endpoints at the individual organism level. To bridge the gap between what is measured and what is intended for protection, individual-level effects can be integrated in population models, and translated to the population level. The general aim of this doctoral thesis was to extrapolate individual-level effects of harpacticoid copepods to the population level by developing and using population models. Matrix models and individual based models were developed and applied to life-history data of Nitocra spinipes and Amphiascus tenuiremis, and demographic equations were used to calculate population-level effects in low- and high-density populations. As a basis for the population models, individual-level processes were studied. Development was found to be more sensitive compared to reproduction in standard ecotoxicity tests measuring life-history data. Additional experimental animals would improve statistical power for reproductive endpoints, but at high labor and cost. Therefore, a new test-design was developed in this thesis. Exposing animals in groups included a higher number of animals without increased workload. The number of reproducing females was increased, and the statistical power of reproduction was improved. Individual-level effects were more or equally sensitive compared to population-level effects, and individual-level effects were translated to the population level to various degrees by population models of different complexities. More complex models showed stronger effects at the population level compared to the simpler models. Density dependence affected N. spinipes populations negatively so that toxicant effects were stronger at higher population densities. The tools presented here can be used to assess the toxicity of environmental contaminants at the individual and population level, improve ERA, and thereby the basis for environmental management.

Place, publisher, year, edition, pages
Stockholm: Department of Applied Environmental Science (ITM), Stockholm University, 2014. 36 p.
Population modeling, (Eco)toxicity tests, Environmental risk assessment, Harpacticoid copepods
National Category
Environmental Sciences
Research subject
Applied Environmental Science
urn:nbn:se:su:diva-102541 (URN)978-91-7447-894-5 (ISBN)
Public defence
2014-05-23, Nordenskiöldsalen, Geovetenskapens hus, Svante Arrhenius väg 12, Stockholm, 09:30 (English)
Mistra - The Swedish Foundation for Strategic Environmental Research, 1323907

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 4: Manuscript.

Available from: 2014-04-30 Created: 2014-04-08 Last updated: 2014-05-29Bibliographically approved

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