Evaluation of the phytotoxic effects of pharmaceuticals in aquatic higher plants
Bibliographic record
Abstract
Pharmaceuticals are biologically active, ubiquitous, low-level contaminants which are continuously introduced into the environment at volumes comparable to pesticides. Typically detected in the ng/L to [mu]g/L range, the effects of these contaminants in the aquatic environment are largely uncharacterized. In order to address this data gap, over 30 pharmaceuticals were screened through laboratory assays with 'Lemna gibba', 12 in aquatic microcosms with 'L. gibba, Myriophyllum sibiricum' and/or 'Myriophyllum spicatum', and 2 at the molecular/biochemical level in 'L. gibba'. Among the pharmaceuticals initially screened, only fluoroquinolone, sulfonamide, and tetracycline antibiotics proved to be phytotoxic between 10-1000 [mu]g/L, however, no significant risks were found using conservative assumptions. Similarly, a microcosm assessment with an eight pharmaceutical mixture indicated no significant risks for either 'L. gibba' or 'M. sibiricum', though fluoroquinolone (levofloxacin) and sulfonamide (sulfamethoxazole) antibiotics, as well as a blood lipid regulator (atorvastatin) were identified as phytotoxic components. Tylosin, a macrolide antibiotic heavily used as a prophylactic in Canadian agriculture, was found to cause no statistically significant inhibition in any endpoint measured in 'L. gibba' or 'M. spicatum' evaluated singly in aquatic microcosms. Although a mixture of tetracyclines was found to pose little risk to the floating macrophyte 'L. gibba', the submerged macrophyte 'M. sibiricum' showed significant inhibition and potential risks, largely because of the reduction in light penetrating the water column by as much as 99.8% at a depth of 70 cm caused by parent compounds and/or metabolites. A probabilistic ecological hazard assessment designed to address the unique data availability of pharmaceuticals revealed low probability for risk to aquatic macrophytes in all cases, with the exception of tetracyclines. Statin class blood lipid regulators were found to significantly reduce metabolite levels (sterols) downstream of the target enzyme (3-hydroxy-3methylglytaryl coenzyme-A reductase) in the mevalonic acid pathway by as much as 90%. However, no significant hazards were identified, though these pathway-specific endpoints were on average 3 times more sensitive than gross morphological endpoints. Therefore, from the subset of pharmaceuticals tested, these compounds appear to pose little risk to aquatic higher plants, evaluated in the laboratory, microcosms or using pathway-specific endpoints.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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 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".