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Asbestos-related pleural disease
Published in Dorsett D. Smith, The Health Effects of Asbestos, 2015
The identification of diffuse pleural changes suggests an intermediate exposure between the very low exposure necessary to cause pleural plaques, and the heavy exposure necessary to cause asbestosis. Very low levels of amphibole exposure (<1 fiber/cc-year) may be sufficient to produce pleural plaques. A study by Larson and colleagues found that 46% of individuals exposed to vermiculite in Libby, Montana, had pleural thickening at a median exposure of 3.6 fibers/cc-year. (Larson TC, Antao VC, Bove FJ, Cusack C. Association between cumulative fiber exposure and respiratory outcomes among Libby vermiculite workers. J Occup Environ Med 2012;54(1):56–63; Christensen KY, Bateson TF, Kopylev L. Low levels of exposure to Libby amphibole asbestos and localized pleural thickening. J Occup Environ Med 2013;55:1350–5.)
Commercial cultivation of cannabis
Published in Betty Wedman-St. Louis, Cannabis, 2018
Mother Nature contributes to the plants through natural sunlight and fresh air, which minimizes the amount of artificial resources needed to maintain healthy plants. Different strains are successful with outdoor grows and usually produce many seeds [1]. Basic grower requirements for a successful outdoor cultivation are the quality of the light, soil, and water sources. Well-irrigated soil with a pH of 6.5 is ideal for growing cannabis outdoors. Natural fresh water is the best source for watering plants, but ensure the soil is not too moist from the natural source, as it will cause root rot. Components such as sand and vermiculite can be added to the soil to aid with water retention and loss. As the fall season approaches, frost may be a factor that could harm plants. The best way to protect plants from frost and wind is to cover them until the weather changes. The plants need direct sunlight for at least four hours every day from mid-morning through the afternoon. An outdoor cultivation can produce mature flower in approximately three months, starting in late springtime after the last frost of the year. This timeline will give the flowering plants shorter amounts of daylight during August and September [1]. Outdoor high-density grows typically place plants 6 inches apart. High-density grows yield more product per harvest, but heavy branch will lead to the constant need for crop work and crop maintenance. Orchard-style grows have larger spacing between plants and yield less per square foot; however, less maintenance and crop work is needed through the plant's growth cycle. Equipment needed for an outdoor grow is mostly restricted to the crop work needed to maintain healthy plants. In the case that a frost may occur, covering plants protects them from frostbite.
Natural mineral fibers: conducting inhalation toxicology studies – part A: Libby Amphibole aerosol generation and characterization method development
Published in Inhalation Toxicology, 2023
Anbo Wang, Amit Gupta, Michael D. Grimm, David T. Pressburger, Barney R. Sparrow, Jamie S. Richey, John R. Shaw, Karen E. Elsass, Georgia K. Roberts, Pei-Li Yao, Matthew D. Stout, Benjamin J. Ellis, Robyn L. Ray
In some cases, humans are exposed to, or have the potential for exposure to, naturally occurring asbestos and related fibrous minerals inadvertently, due to contamination of other materials with fibers, or due to natural outcroppings of fibrous material in the environment. One such exposure was via contaminated vermiculite, a hydrous phyllosilicate mineral which undergoes significant expansion when heated. Vermiculite has a number of industrial and consumer uses, including insulation, soilless growth medium/soil conditioning, and packing/shipping. The vermiculite mine near Libby, Montana (MT) was the major source (nearly 80%) of the world’s supply of vermiculite from 1920 to 1990 for products used in commercial and residential settings (Winters et al. 2011). Mixed minerals, primarily winchite, richterite, with a small amount of tremolite with a range of crystal morphologies, were found in the Libby vermiculite ore, and referred to as Libby amphibole asbestos. An early study in 1986 revealed an increased mortality rate among Libby vermiculite mine workers (McDonald et al. 1986). A growing body of evidence further suggested that human exposure to Libby amphibole asbestos increased risk of lung cancer, mesothelioma, and nonmalignant respiratory disease in both occupational and nonoccupational populations (Benson et al. 2015; Szeinuk et al. 2017; Pfau et al. 2019; Dodson et al. 2020).
Autoimmune markers for progression of Libby amphibole lamellar pleural thickening
Published in Inhalation Toxicology, 2019
Jean C. Pfau, Tracy McNew, Kerensa Hanley, Lindsay Swan, Brad Black
The CARD maintains an extensive database of the LAA-exposed population through their research program, now containing almost 7000 patient records. From this database, subjects were selected who met criteria to identify individuals with no evidence of LPT, patients with stable LPT and those with progressive LPT. All subjects in the database have had exposure to LAA, documented by exposure routes including occupational, residential and environmental exposures. Occupational exposures tend to be highest due to directly working with the ore, but household and environmental exposures can also be high due to the extensive use of the vermiculite ore in home insulation, gardening, and surfacing of ball fields, playgrounds, and roads (Noonan 2006; Noonan et al. 2015). Dust with high levels of LAA fibers was also brought home on worker clothing. In addition, studies have demonstrated health effects of LAA even at very low (environmental) exposure levels in both mice and humans (Black et al. 2014; Szeinuk et al. 2016; Pfau et al. 2017).
Facilitation of non-indigenous ascidian by marine eco-engineering interventions at an urban site
Published in Biofouling, 2023
Nina Schaefer, Francisco Sedano, Melanie J. Bishop, Kate Dunn, M. Hank Haeusler, K. Daniel Yu, Yannis Zavoleas, Katherine A. Dafforn
All panels were cast using a standard concrete mixture including Special Purpose Cement (Boral Cement Limited), white-washed sand (Dingo Cement Australia Pty Ltd) and 5-10 mm coarse aggregate (Screenings – Dingo Cement Australia Pty Ltd). For the standard concrete tiles (hereafter ‘concrete’), the ratio of cement to sand and aggregate was 2:1:2 (by volume). For the ‘oyster’ and ‘vermiculite’ mixtures, 50% of the coarse aggregate was replaced by granulated oyster shells (<10 mm pieces) or vermiculite (Bunnings Vermiculite). Oyster shell was sourced from the Sydney fish markets, and comprised a mix of Saccostrea glomerata and Crassostrea gigas, that had been cleaned (through brushing), dried (at 110 °C for 24 h) and granulated (with a hammer). Pieces that fell through a 10 mm mesh sieve were included in the concrete mixture. Recycled oyster shell was selected as an aggregate substitute based on previous studies that have found oysters are gregarious settlers, attracted to the chemical cues of shell (Tamburri et al. 2008). Vermiculite was used as it is porous and absorbs water, making it a variable-textured anchor point in the hard concrete for various species. While of comparatively low strength compared to other additives, it is an attractive option for inclusion in eco-engineering interventions, due to its low density, which can decrease the weight of concrete castings used to be fitted onto existing infrastructure (Dunn et al. 2019, Hornbostel 1991). Ten tiles of each of the six treatments (i.e. n = 60 tiles total) were cast in January 2019 and air cured until deployment in April 2019. Another two tiles of each of the six treatments (i.e. n = 12 tiles in total) were also cast in January 2019 and directly used in mesocosm experiments.