SCIENTIFIC STUDY
University of Arizona presentation on potential fly sources in Yuma
About this source
Presentation by Paula Rivadeneira dated April 24, 2018, describing fieldwork in 2017.
- Source type
- Scientific study
- Source classification
- Primary source
- Source date
Relevant excerpt / notes
Presentation by Paula Rivadeneira dated April 24, 2018, describing March 13–May 13, 2017 fieldwork. Slides 13–14 identify six participating sites and daily emergence-trap checks. Slide 15 reports average flies per square metre per day for biosolids (2), landfill (1) and salad waste (3,877). The original chart was visually inspected September 20, 2026, resolving the earlier chart-access limitation. One biosolids pivot participated. Slides 19 and 40–41 caution against treating one identified source as the sole source and call for further work. These are not countywide percentages or a 2026 source-attribution study; the raw dataset was not independently audited.
Publisher / issuing organization 1
Related claims 4
- Needs ContextA historical Yuma study chart reports average daily fly-emergence rates of 3,877 for salad waste, 2 for biosolids and 1 for landfill, per square metre.
These are charted rates from selected sites in 2017, not countywide population percentages or measurements of 2026 conditions.
- UnverifiedClaim under review: Was AgTech the main source of Yuma’s regional fly problem in 2026?
This page documents an unresolved claim or research lead. It is not a finding of fact. UNRESOLVED. CAUSATION NOT ESTABLISHED. No controlled 2026 regional source-attribution study was reviewed.
- Needs ContextDo older studies prove AgTech can never breed flies?
The historical evidence cannot support an all-sites, all-times absence claim.
- Needs ContextThe County attributes less than 1% of sampled larvae to biosolids or septage sites.
The County’s statement is documented; the percentage is not independently reproduced.
Timeline events 1
- University presentation reviews selected Yuma fly sources
Paula Rivadeneira’s presentation is dated April 24, 2018 and describes 2017 fieldwork. The presentation date is distinct from the sampling period.
Related articles 2
- ExplainerAgTech and Yuma’s Biosolids Dispute: A Timeline of Research, Inspections and State Action
A chronology of supported research, requests and public actions, with event dates kept separate from scientific findings.
- ExplainerWhat Yuma’s Fly Studies and AgTech Inspections Actually Found
Historical studies, County statements and current complaints answer different questions. None should be made to prove more than it measured.
People 1
- Paula Rivadeneira
Paula Rivadeneira is identified with the University of Arizona Yuma Agricultural Center on the April 24, 2018 presentation about potential fly sources. The role is historical; current employment is not inferred.
Organizations 2
- South Yuma County Landfill
The South Yuma County Landfill is named as a study location in the historical fly research. This reference does not establish available capacity, a biosolids acceptance commitment or current pricing.
- University of Arizona
University researchers and extension personnel produced historical Yuma fly research and PFAS studies. The institution’s communications articles are distinguished from original studies.
Related topics 1
- Yuma Biosolids / AgTech
A source-first guide to Yuma’s biosolids debate: State Land leases, AgTech’s reported formal challenge, the City contract, fly research, PFAS questions and the records still needed.