Showing papers by "George A. O'Connor published in 2019"
TL;DR: The results suggest that land application of biosolids-borne CIP and AZ pose De minimis risks to plants, suggesting minimal impacts of the target TOrCs on human and/or animal food chains.
35 citations
TL;DR: The results suggest that biosolids-borne CIP and AZ toxicity to terrestrial microbes and earthworms is minimal, but there is a potential for target TOrC entry into ecological food web.
31 citations
TL;DR: Results obtained using equilibrium and dynamic approaches suggest that the target antibiotic bioaccessibilities from biosolids and finer-textured (typical agricultural) soils would be minimal and that biosoliids (not soils) control desorption of the two biosolid-borne chemicals.
20 citations
TL;DR: Overall, the results reveal different impacts of the two soil amendments, where FBP soil application can affect the labile SOC availability, and stimulate rapid microbial response in drought affected soils, and biochar soil application lowers thelabile SOC and microbial stimulation facilitating C sequestration over time.
18 citations
TL;DR: Biosolids-borne antibiotic resistance (currently not addressed in any risk assessment model) is the principal uncertainty limiting risk assessment of biosolid-borne antibiotics including CIP and AZ.
11 citations
15 Oct 2019
TL;DR: The results indicate that none of component of soilless media has a universally high attraction for all of the pesticides studied.
Abstract: Commercial producers of containerized ornamental plants almost exclusively use soilless media as the substrate for growing the plants. Soilless media are composed primarily of organic materials as ...
10 citations
TL;DR: Results demonstrate the value of water-extractable P (WEP) as an indicator of biosolids P loss potential and identify and thoroughly characterize the main biosolid sources routinely applied in the region.
Abstract: Recent evidence suggests an upward trend in surface water phosphorus (P) concentrations in many segments of Florida, including the upper basin of the St. Johns River, a region that currently receives about two-thirds of the state Class B biosolids land application. Concerns about water quality in this area are encouraging reexamination of the regulations governing biosolids programs. The objectives of this study were (i) to identify and thoroughly characterize the main biosolids sources routinely applied in the region, and (ii) to evaluate runoff and leachate N and P losses from a typical Florida Spodosol amended with biosolids or commercial inorganic fertilizer. Biosolids and inorganic fertilizer were surface applied uniformly at a rate equivalent to ∼114 kg P ha, which corresponded to a typical P load associated with nitrogen (N)-based biosolids application. Soluble reactive P (SRP) was the predominant form of P lost in runoff and leachate. Inorganic P fertilizer increased flow-weighted runoff total P concentrations nearly 60-fold relative to control treatment (0.4 vs. 22 mg P L for control and fertilizer treatments, respectively). With exception of biological P removal (BPR) biosolids, all other tested biosolids yielded flow-weighted runoff P concentrations similar to untreated soils. Cumulative P and N losses (as a percentage of P and N applied) were greater from commercial inorganic fertilizer (∼38% of P and 46% of N) than any biosolids source (3% of P and 6% of N). Results demonstrate the value of water-extractable P (WEP) as an indicator of biosolids P loss potential.
8 citations
12 Aug 2019
TL;DR: In this article, the authors explore possible effects of land-applying aluminum-based WTR on the environment and recommend practices to minimize environmental or human and animal health risk, and recommend a best management practice (BMP) to reduce off-site P losses from agricultural fields via runoff and leaching.
Abstract: Land application of aluminum-based WTRs (Al-WTR) has been demonstrated to effectively control off-site phosphorus loss to surface and groundwater. Therefore, amending soil with Al-WTR could be a best management practice (BMP) to reduce off-site P losses from agricultural fields via runoff and leaching. However, environmental concerns that the aluminum and arsenic contents of Al-WTRs could negatively affect agricultural production and human health have led to the development of guidelines for land application of WTRs in Florida. This document explores possible effects of land-applying Al-WTR on the environment and recommends practices to minimize environmental or human and animal health risk. Target audiences include state agencies like FDEP, FDACS, water management districts trying to use Al-WTR to control P pollution, and those interested in nutrient management for environmental purposes.
2 citations