Distribution, Fate, and Behavior of Nonylphenol Ethoxylates and Degradation Products in the Dispersion Plume of a Major Municipal Wastewater Effluent
Bibliographic record
Abstract
The aim of this study was to estimate the distribution, fate, and behavior of p-nonylphenols (p-NPs: p-n-nonylphenol and its isomers), nonylphenol ethoxylates (NP1–17EOs), and nonylphenol carboxylic acids (NP1–2ECs) in the municipal wastewater effluent (MWWE) of the City of Montreal, Canada, and in the receiving waters of the St. Lawrence River. The MWWE was sampled at the Montreal wastewater treatment plant, while surface water was sampled at sites located upstream and downstream of the effluent outfall. Twenty-four hour composite samples were obtained at the treatment plant on three nonconsecutive days during the summer of 2002. Water samples were filtered, then particulate and dissolved phases were extracted using Soxhlet and solid-phase extraction techniques, respectively, prior to LC/MS/MS analysis for the compounds of concern. The effluent contained essentially dissolved (75.4%, 375 kg/day) and particulate (23.7%, 118 kg/day) NP1–17EOs. By contrast, the surface water downstream of the outfall contained p-NPs at an average of 9.8% and dissolved NP1–2ECs (1.3%), as well as dissolved NP1–17EOs (86.7%) and a small fraction of particulate NP1–17EOs (2.1%). All NPnEOs and their degradation products were present in higher amounts in the dissolved phase (particulate/dissolved ratio < 1) than in the particulate phase in both the wastewater and surface water. In the surface waters downstream of the effluent outfall, an average of 89% of the particulate NP1–17EOs was rapidly released (within 1.5 h) into the dissolved phase during the physical exchange, and there were variances in changes in the phase distribution among the compounds being studied. Following this relatively fast phase transfer in the receiving waters, 30% of total NP1–17EOs were lost, 25% of p-NPs and NP1–2ECs were formed by the degradation of a fraction (6%) of NP1–17EOs, and 24% of NP1–17EOs loss remains unexplained.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".