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The pesticide registration process in North America, including the USA and Canada, involves conducting a risk assessment based on relatively conservative modeling to predict pesticide concentrations in receiving waterbodies. The modeling framework does not consider some commonly adopted best management practices that can reduce the amount of pesticide that may reach a waterbody, such as vegetative filter strips (VFS). Currently, VFS are being used by growers as an effective way to reduce off‐site movement of pesticides, and they are being required or recommended on pesticide labels as a mitigation measure. Given the regulatory need, a pair of multistakeholder workshops were held in Raleigh, North Carolina, to discuss how to incorporate VFS into pesticide risk assessment and risk management procedures within the North American regulatory framework. Because the risk assessment process depends heavily on modeling, one key question was how to quantitatively incorporate VFS into the existing modeling approach. Key outcomes from the workshops include the following: VFS have proven effective in reducing pesticide runoff to surface waterbodies when properly located, designed, implemented, and maintained; Vegetative Filter Strip Modeling System (VFSMOD), a science‐based and widely validated mechanistic model, is suitable for further vetting as a quantitative simulation approach to pesticide mitigation with VFS in current regulatory settings; and VFSMOD parametrization rules need to be developed for the North American aquatic exposure assessment. Integr Environ Assess Manag 2024;20:454–464. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). Key Points: The pesticide registration process in North America involves conducting a risk assessment based on relatively conservative modeling to predict pesticide concentrations in receiving waterbodies, but the modeling framework does not consider some commonly adopted best management practices.Vegetative filter strips (VFS) have proven effective in reducing pesticide runoff to surface waterbodies when properly located, designed, implemented, and maintained.The Vegetative Filter Strip Modeling System (VFSMOD), a science‐based and widely validated mechanistic model, is suitable for further vetting as a quantitative simulation approach to pesticide mitigation with VFS in current regulatory settings.VFSMOD parametrization rules need to be developed for the North American aquatic exposure assessment. [ABSTRACT FROM AUTHOR]

Fugacity and bioavailability can be used to facilitate students' understanding of potential environmental risks associated with toxic chemicals and, therefore, should be incorporated in environmental chemistry and science laboratories. Although the concept of concentration is easy to grasp, fugacity and bioavailability can be challenging topics to communicate effectively in the timeframe of an academic laboratory course setting. In the experiment reported here, students observed the partitioning of chemical residues over time from soil into an artificial biological matrix. The two compounds utilized here as examples are commonly found in historically contaminated agricultural sites: 1,1,1-trichloro-2,2-di(4-chlorophenyl)ethane (DDT) and 1,1-bis-(4-chlorophenyl)-2,2-dichloroethane (DDE). A known quantity of the compounds was spiked and mixed into soil, which was then placed in replicate glass vials coated with a thin layer of polymer to mimic contact between soil and an organism. The polymer was then extracted and analyzed by standard gas chromatography-mass spectrometry (GC-MS). The fugacity gradient across the soil-polymer interface and the hydrophobic nature of the compounds drive the residues into the polymer, illustrating the concept of fugacity. A number of variations of this experiment, such as the comparison of different soils or the use of different contaminants could also be utilized for more advanced laboratory courses. (Contains 4 figures.)

Doi: 10.1080/10473289.2011.599282 Particulate matter (PM) emitted from cattle feedlots are thought to affect air quality in rural communities, yet little is known about factors controlling their emissions. The concentrations of [...]

Complaints due to odors are an important problem for the wastewater, composting, and animal agriculture industries. Accurate, objective measurement techniques are needed to monitor emissions, to develop new waste handling procedures, and to reduce the production of these volatile gases. Solid-phase microextraction was investigated as a technique for the determination of representative odorous gases. A flow-through Teflon chamber was used to expose the fibers to certified gas standards. A 75-[micro] m carboxen-poly(dimethylsiloxane) (Car-PDMS) coating was used for trimethylamine (TMA), carbon disulfide (C[S.sub.2]), dimethylsulfide (DMS), and dimethyl disulfide (DMDS), and an 85-[micro] m polyacrylate coating was used for propionic acid (PA) and butyric acid (BA). Using a 1-h fiber exposure time and a flow rate through the chamber of 72 mL/min, method detection limits were 2.38, 0.074, 0.150, 0.063, 1.85, and 1.32 ppbv for TMA, DMS, C[S.sub.2], DMDS, PA, and BA, respectively. Enhanced detector signal was observed for all analytes under flow conditions, as compared to static conditions, and the porous nature of the Car-PDMS coating appears to increase the time needed for analytes to reach equilibrium under flow conditions.

This article examines pesticide concentrations in the air, rain, and surface water of an estuary of Chesapeake Bay.

Polychlorinated biphenyl (PCB) congener concentrations in air, water, fish and snow were taken and correlated with PCB mass budget to produce evidence for atmospheric transport and deposition of PCB in the alpine lake region of the Lake Tahoe Basin. The results were likewise compared with the PCB concentrations found in nearby Marlette, and showed similar PCB concentrations in fish and water samples.

Distributions of organochlorine pesticides and polychlorinated biphenyls (PCBs) in Lake Baikal, Russia, were determined by measuring the concentrations of these compounds from air and water samples collected in June 1991. Air concentrations of chlorinated bornanes, chlordanes and hexachlorobenzene were similar to those measured in the Arctic regions, but air concentrations of hexachlorocyclohexanes, DDTs and PCBs were similar to those in the Great Lakes region. Measurements from air samples in nearby Irkutsk were higher than those for Lake Baikal, suggesting regional transport and deposition of organochlorine pesticides and PCBs.

Research has investigated the direction and rate of hexachlorocyclohexane (HCH) or Lindane gas exchange between air and water in Lakes Michigan, Huron, Erie and Ontario. The project aimed to facilitate monthly predictions of HCH gas flux. Air and water samples were collected in June, 1989 and August, 1990. A fugacity gradient established an air to water flux direction during periods of high air concentration and low surface water temperatures. Higher water temperatures during summer produced short periods of volatility.

Six di- to tetra chlorophenols were collected from 285-380 cubic meters of analyte-spiked air using adsorbent traps containing five to six gramsof Tenax-GC sandwiched between two 3-cm-thick polyurethane foam plugs. Mass balance of the quantities introduced and recovered determined the collection efficiencies which averaged 63 to 96 percent for individual compounds, with an overall mean of 83 percent.