The water-sediment interactions for Hyalella azteca exposed to uranium-spiked or contaminated sediments and different overlying water chemistries
Bibliographic record
Abstract
In comparison with other metals such as Cd, Cu, Pb, Ni, and Zn, little is known about uranium (U) toxicity to Hyalella azteca. There is even no national U water or sediment quality guideline yet for the protection of aquatic life in Canada, despite Canada being home to some of the biggest U producers in the world. In this context, the aim of this research was to determine the toxic effects of U concentrations in the water and sediment to H. azteca, and if these relationships can be modelled. This thesis demonstrated that U bioaccumulation was mainly via the water phase rather than the sediment phase. It showed that U bioaccumulation measurements in H. azteca were more reliable indicators of U toxicity than U concentrations in the water or sediment. A water-bioaccumulation saturation model was satisfactory at describing this relationship. Overlying water chemistry was found not only to influence U bioaccumulation and toxicity in the H. azteca but also the desorption of U in the sediment into the overlying water. A water-sediment partitioning saturation model was also satisfactory at explaining these interactions. \n\t Both body size and gut-content had an overall effect on U bioaccumulation in H. azteca exposed to water-only U concentrations in soft water. A saturation model was used not only to estimate the effect of gut-content on U bioaccumulation, but to predict the uptake and elimination rate constants for H. azteca exposed to water-only U concentrations. \n\tA field study was conducted to determine if the saturation models developed and applied in the laboratory could be used in the field to quantify U bioavailability, bioaccumulation and toxicity to H. azteca. Unfortunately, U concentrations in the water and sediment were below concentrations needed to validate these models. However, toxicity, not related to U concentrations in the field, was observed at some field sites. \n\tOverall this thesis not only encourages more work on U toxicity to H. azteca, but provides significant data and models to be used by risk assessors and regulators in the development of U water and sediment quality guidelines in the protection of aquatic environments in Canada.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".