Inactivation of Cryptosporidium oocysts and Giardia cysts by ultraviolet light in the presence of natural particulate matter
Bibliographic record
Abstract
Research Article| May 01 2005 Inactivation of Cryptosporidium oocysts and Giardia cysts by ultraviolet light in the presence of natural particulate matter Kingsford Amoah; Kingsford Amoah 1City of Lethbridge, City Hall, 910 4th Avenue SouthLethbridge, Alberta T1J 0P6, Canada Search for other works by this author on: This Site PubMed Google Scholar Stephen Craik; Stephen Craik 2Department of Civil and Environmental Engineering, 3-133 Markin/CNRL Natural Resources Engineering FacilityUniversity of Alberta, Edmonton, Alberta T6G 2W2, Canada Tel: +1 780 492 8293 Fax: +1 780 492 8289; E-mail: scraik@civil.ualberta.ca Search for other works by this author on: This Site PubMed Google Scholar Daniel W. Smith; Daniel W. Smith 2Department of Civil and Environmental Engineering, 3-133 Markin/CNRL Natural Resources Engineering FacilityUniversity of Alberta, Edmonton, Alberta T6G 2W2, Canada Search for other works by this author on: This Site PubMed Google Scholar Miodrag Belosevic Miodrag Belosevic 3Department of Biological Sciences, CW 330 Biological Sciences BldgUniversity of Alberta, Edmonton, Alberta T6G 2E9, Canada Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2005) 54 (3): 165–178. https://doi.org/10.2166/aqua.2005.0016 Article history Received: July 17 2003 Accepted: October 16 2004 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Twitter LinkedIn Tools Icon Tools Cite Icon Cite Permissions Search Site Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentAll JournalsThis Journal Search Advanced Search Citation Kingsford Amoah, Stephen Craik, Daniel W. Smith, Miodrag Belosevic; Inactivation of Cryptosporidium oocysts and Giardia cysts by ultraviolet light in the presence of natural particulate matter. Journal of Water Supply: Research and Technology-Aqua 1 May 2005; 54 (3): 165–178. doi: https://doi.org/10.2166/aqua.2005.0016 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Recent studies have shown that ultraviolet (UV) radiation reduces the infectivity of Cryptosporidium parvum oocysts and Giardia spp. cysts. The objective of this work was to further examine UV inactivation of C. parvum oocysts and G. muris cysts in the presence of suspended particulate matter. Naturally occurring particulate matter consisting of a heterogeneous mixture of biological and non-biological particles, mainly in the 5–25 μm size range, was concentrated from a lake. Different aliquots of this material were mixed with purified oocyst and cyst preparations in aqueous suspensions, and the suspensions were exposed to UV fluences of 5 and 40 mJ/cm2 from a medium-pressure mercury arc lamp using a collimated beam apparatus. Parasite inactivation was determined using mouse infectivity assays. Addition of particulate matter was correlated with statistically significant reductions in C. parvum and G. muris inactivation of 0.8 log10 and 0.4 log10, respectively, even after the fluence was adjusted for increased absorbance due to the presence of the particles. The corresponding increases in turbidity were 0.3–20 NTU for C. parvum and 7.5–20 NTU for G. muris. The magnitude of the effect was a function of the final suspension turbidity but was independent of fluence. In this study, the effect of particles on parasite inactivation at turbidity values of less than 10 NTU was small and difficult to measure, and would likely be unimportant in practice. Although the mechanism for this reduction was not determined, the results suggest that the particulate matter present in natural surface waters may interact with oocysts and cysts and thereby result in a reduction in UV inactivation over and above that attributable to simple absorbance. The effect of turbidity on inactivation measured in this work may not necessarily apply generally since the characteristics of the particles that compose turbidity may differ considerably between water sources. collimated beam, Cryptosporidium, disinfection, Giardia, particles, particulates, turbidity, ultraviolet This content is only available as a PDF. © IWA Publishing 2005 You do not currently have access to this content.
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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 | 0.001 | 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 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".