23 sediment quality guidelines Flashcards
what are the chapters of canadian environmental quality guidelines?
what is the outline and outcomes of this lecture?
purpose
-to introduce students to the basic concepts of sediment and sediment quality guidelines
outcomes: students should be able to answer the following
-what is sediment?
-why is sediment important?
-how can sediments become problematic?
-how were CCMA sediment quality guidelines developed?
-what are the uses and limitations of these guidelines?
what is the focus of this lecture?
canadian sediment quality guidelines (SQGs) for the protection of aquatic life
what are sediments?
particles derived from rocks or biological materials that are stationary in the bottom of a water course (inorganic and organic matter)
why is bed sediment important?
-bottom sediment provides habitat for many organisms
-it plays a role in nutrient cycling (C, N, P)
-sediment can accumulate contaminates (i.e. act as a sink) and thereby become a source of contaminants
-toxicologically, sediment can become acutely or chronically toxic to organisms or act as a source of chemicals that can bioaccumulate in aquatic food webs (ex: mercury)
what does doig do in his research?
what was looked at in ross lake manitoba?
-1910-1920=found deposits and made a mine
-many people moved there, and they dumped raw sewage into lake
what were the trace elements in ross lake?
what is the ideal approach of SQGs?
what are the guiding principles?
-SQGs are numerical concentrations or narrative statements intended to protect all forms of aquatic life and all aspects of their aquatic life cycles during an indefinite period of exposure to substances associated with bed sediments
-recommended use: canadian interim sediment quality guidelines (ISQGs) and probable effect levels (PELs) can be used to evaluate the degree to which adverse biological effects are likely to occur due to exposure to a substance in sediment
-common use: they provide conservative (protective) concentrations below which toxic effects are unlikely and identify sites for further assessment
what is the concentration and effect of zinc?
not based on cause and effect data (can just say one thing causes all biological adverse effects)
what is the general premise?
-the ISQGs and PELs refer to total concentrations of an element/trace metal in surficial sediments (i.e. 5 cm), as quantified by digestion with a strong acid (e.g. aqua regia, nitric acid, or hydrochloric acid), followed with analysis by a standard analytical protocol
what are the potential application of SQGs?
- national benchmarks to assess whether existing or predicted sediment quality conditions pose a threat to benthic organisms
- defining site-specific objectives to maintain and protect sediment quality conditions
- defining site-specific remediation objectives to improve sediment quality conditions
note: for sediments of superior quality, “impairment” to the national SQGs should not be advocated
what are the limitations of sediment quality tests?
what is the concentration of arsenic?
what is the PEL of ross lake?
