Developing and applying control charts to detect changes in water chemistry parameters measured in the Athabasca River near the oil sands: A tool for surveillance monitoring
Bibliographic record
Abstract
Control charting is a simple technique to identify change and is well suited for use in water quality programs. Control charts accounting for covariation associated with discharge and in some cases time were used to explore example and representative variables routinely measured in the Athabasca River near the oil sands area for indications of change. The explored variables include 5 major ions (chloride, sodium, sulfate, calcium, magnesium), 5 total metals (aluminum, iron, thallium, molybdenum, vanadium), and total suspended solids at two sites straddling the developments north of Fort McMurray. Regression equations developed from reference data (1988-2009) were used to predict observations and calculate residuals from later test data (2010-2016). Evidence of change was sought in the deviation of residual errors from the test period compared with the patterns expected and defined from probability distributions of the reference residuals using the odds ratio. In most cases, the patterns in test residuals were not statistically different from those expected from the reference period at either site, especially when data were examined annually. However, differences were found at both locations, more were found at the downstream site, and more differences emerged as data accumulated and were analyzed over time. In sum, the analyses at the downstream site suggest higher concentrations than predicted in most major ions, but the source of the changes is uncertain. In contrast, the concentrations of most metals at during the test period were lower than expected, which may be related to deposition patterns of materials or weathering of minerals during construction activities of the 2000s which influence the reference data used. The analyses also suggest alternative approaches may be necessary to understand change in some variables. Despite this, the results support the use of control charts to detect changes in water chemistry parameters and the value of the tool in surveillance phases of long-term and adaptive monitoring programs. Environ Toxicol Chem 2018;37:2296-2311. © 2018 SETAC.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.012 | 0.035 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.009 | 0.005 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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 source (direct Gemma or distilled Codex), 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".