Impact of iron particles in groundwater on the UV inactivation of bacteriophages MS2 and T4
Bibliographic record
Abstract
AIMS: To investigate the impact of iron particles in groundwater on the inactivation of two model viruses, bacteriophages MS2 and T4, by 254-nm ultraviolet (UV) light. METHODS AND RESULTS: One-litre samples of groundwater with high iron content (from the Indianapolis Water Company, mean dissolved iron concentration 1.3 mg l(-1)) were stirred vigorously while exposed to air, which oxidized and precipitated the dissolved iron. In parallel samples, ethylenediaminetetra-acetic acid (EDTA) was added to chelate the iron and prevent formation of iron precipitate. The average turbidity in the samples without EDTA (called the 'raw' samples) after 210 min of stirring was 2.7 +/- 0.1 NTU while the average turbidity of the samples containing EDTA (called the 'preserved' samples) was 1.0 +/- 0.1 NTU. 'Raw' and 'preserved' samples containing bacteriophage MS2 were exposed to 254-nm UV light at doses of 20, 40, or 60 mJ (cm(2))(-1), while samples containing bacteriophage T4 were exposed to 2 or 5 mJ (cm(2))(-1), using a low pressure UV collimated beam. The UV inactivation of both phages in the 'raw' groundwater was lower than in the EDTA-'preserved' groundwater to a statistically significant degree (alpha = 0.05), due to the association of phage with the UV-absorbing iron precipitate particles. A phage elution technique confirmed that a large fraction of the phage that survived the UV exposures were particle-associated. CONCLUSIONS: Phages that are associated with iron oxide particles in groundwater are shielded from UV light to a measurable and statistically significant degree at a turbidity level of 2.7 NTU when the phage particle association is induced under experimental conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: While the particle association of the phage in this study was induced experimentally, the findings provide further evidence that certain particles in natural waters and wastewaters (e.g. iron oxide particles) may have the potential to shield viruses from UV light.
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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 | 0.000 | 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 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".