An evaluation of SASS (South African scoring system) as a tool for the rapid bioassessment of water quality

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dc.contributor.advisorDay, Jennyen_ZA
dc.contributor.authorDallas, Helen Fionaen_ZA
dc.date.accessioned2016-08-11T09:51:07Z
dc.date.available2016-08-11T09:51:07Z
dc.date.issued1995en_ZA
dc.descriptionBibliography: pages 139-150.en_ZA
dc.description.abstractThe South African Scoring System (SASS) is a rapid bioassessment technique based on one component of riverine biotas, the benthic macroinvertebrates. Each taxon is assigned a tolerance/sensitivity score, which are summed to provide a Total Score. The Average Score per Taxon (ASPT) is calculated by dividing this Total Score by the number of taxa. This study was undertaken to evaluate the SASS technique as a tool for the assessment of water quality. Three study-sites, which differed in water quality, in the south-western Cape were selected for a detailed investigation into sample variability and replication of two methods of biological assessment, namely quantitative box-sampling and SASS. The ability of each method to differentiate between these sites was determined. The more general application of SASS in the south-western Cape was examined at forty nine sites and potential problems associated with SASS, namely biotope availability, temporal variability and longitudinal changes were investigated. A minimum of twelve and four quantitative samples is needed to ensure collection of 95% or 75% of benthic macroinvertebrate taxa respectively. Sampling within a single biotope component, such as a "riffle" or "run" would reduce the number of samples needed. A minimum of four and two SASS samples is needed to ensure collection of 95% or 75% of the taxa respectively. This technique is however designed such that only one sample is taken per site. The Total Score that one sample would produce as a percentage of the Total Score from 20 samples, were 28% , 59% and 45% for Sites 1, 2 and 3 respectively. Total Score increases with increasing sampling effort, whilst ASPT is relatively unaffected by sampling effort. ASPT should therefore be used in interpretation of scores. Variability, as determined by both quantitative sampling and rapid bioassessment, was greatest at the least impacted site. Such sites should be more intensively sampled, either by increasing the number of box- samples taken, or by increasing the time period for SASS sampling.en_ZA
dc.identifier.apacitationDallas, H. F. (1995). <i>An evaluation of SASS (South African scoring system) as a tool for the rapid bioassessment of water quality</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/21180en_ZA
dc.identifier.chicagocitationDallas, Helen Fiona. <i>"An evaluation of SASS (South African scoring system) as a tool for the rapid bioassessment of water quality."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 1995. http://hdl.handle.net/11427/21180en_ZA
dc.identifier.citationDallas, H. 1995. An evaluation of SASS (South African scoring system) as a tool for the rapid bioassessment of water quality. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Dallas, Helen Fiona AB - The South African Scoring System (SASS) is a rapid bioassessment technique based on one component of riverine biotas, the benthic macroinvertebrates. Each taxon is assigned a tolerance/sensitivity score, which are summed to provide a Total Score. The Average Score per Taxon (ASPT) is calculated by dividing this Total Score by the number of taxa. This study was undertaken to evaluate the SASS technique as a tool for the assessment of water quality. Three study-sites, which differed in water quality, in the south-western Cape were selected for a detailed investigation into sample variability and replication of two methods of biological assessment, namely quantitative box-sampling and SASS. The ability of each method to differentiate between these sites was determined. The more general application of SASS in the south-western Cape was examined at forty nine sites and potential problems associated with SASS, namely biotope availability, temporal variability and longitudinal changes were investigated. A minimum of twelve and four quantitative samples is needed to ensure collection of 95% or 75% of benthic macroinvertebrate taxa respectively. Sampling within a single biotope component, such as a "riffle" or "run" would reduce the number of samples needed. A minimum of four and two SASS samples is needed to ensure collection of 95% or 75% of the taxa respectively. This technique is however designed such that only one sample is taken per site. The Total Score that one sample would produce as a percentage of the Total Score from 20 samples, were 28% , 59% and 45% for Sites 1, 2 and 3 respectively. Total Score increases with increasing sampling effort, whilst ASPT is relatively unaffected by sampling effort. ASPT should therefore be used in interpretation of scores. Variability, as determined by both quantitative sampling and rapid bioassessment, was greatest at the least impacted site. Such sites should be more intensively sampled, either by increasing the number of box- samples taken, or by increasing the time period for SASS sampling. DA - 1995 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1995 T1 - An evaluation of SASS (South African scoring system) as a tool for the rapid bioassessment of water quality TI - An evaluation of SASS (South African scoring system) as a tool for the rapid bioassessment of water quality UR - http://hdl.handle.net/11427/21180 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/21180
dc.identifier.vancouvercitationDallas HF. An evaluation of SASS (South African scoring system) as a tool for the rapid bioassessment of water quality. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 1995 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/21180en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Biological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherZoologyen_ZA
dc.titleAn evaluation of SASS (South African scoring system) as a tool for the rapid bioassessment of water qualityen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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