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Emergency service (ambulance, police, fire) call-takers and dispatchers are often exposed to duty-related trauma, placing them at increased risk for developing mental health challenges like stress, anxiety, depression, and posttraumatic stress disorder (PTSD). Their unique working environment also puts them at-risk for physical health issues like obesity, headache, backache, and insomnia. Along with the stress associated with being on the receiving end of difficult calls, call-takers and dispatchers also deal with the pressure and demand of following protocol despite dealing with the variability of complex and stressful situations.
A systematic literature review was conducted using the MEDLINE, PubMed, CINAHL, and PsychInfo databases.
A total of 25 publications were retrieved by the search strategy. The majority of studies (n = 13; 52%) reported a quantitative methodology, while nine (36%) reported the use of a qualitative research methodology. One study reported a mixed-methods methodology, one reported an evaluability assessment with semi-structured interviews, one reported on a case study, and one was a systematic review with a narrative synthesis.
Challenges to physical health included: shift-work leading to lack of physical activity, poor nutrition, and obesity; outdated and ergonomically ill-fitted equipment, and physically confining and isolating work spaces leading to physical injuries; inadequate breaks leading to fatigue; and high noise levels and poor lighting being correlated with higher cortisol levels. Challenges to mental health included: being exposed to traumatic calls; working in high-pressure environments with little downtime in between stressful calls; inadequate debriefing after stressful calls; inappropriate training for mental-health-related calls; and being exposed to verbally aggressive callers. Lack of support from leadership was an additional source of stress.
Emergency service call-takers and dispatchers experience both physical and mental health challenges as a result of their work, which appears to be related to a range of both operational and support-based issues. Future research should explore the long-term effects of these physical and mental health challenges.
In the years following the September 11, 2001 terrorist attacks in New York (USA), otherwise known as 9/11, first responders and recovery workers began experiencing a range of physical and mental health challenges. Publications documenting these provide an important evidence-base identifying exposure-related health challenges associated with environmental exposures from the World Trade Center (WTC) site and describe the key lessons learned regarding both physical and mental health challenges (including symptoms and defined conditions) from the 9/11 disaster response.
A systematic literature review was conducted using the MEDLINE, PubMed, CINAHL, and PsychInfo databases (September 11, 2001 to September 11, 2018) using relevant search terms, truncation symbols, and Boolean combination functions. Publications were limited to journal articles that documented the physical or mental health challenges of 9/11 on first responders or recovery workers.
A total of 156 publications were retrieved by the search strategy. The majority (55%) reported a quantitative methodology, while only seven percent reported the use of a qualitative research methodology. Firefighters were the group of responders most frequently reported in the literature (35%), while 37% of publications reported on research that included a mix of first responders and recovery workers. Physical health was the focus of the majority of publications (57%). Among the challenges, respiratory issues were the physical health condition most frequently reported in publications, while posttraumatic stress disorder (PTSD) was the most frequent mental health condition reported on. Publications were published in a broad range of multi-disciplinary journals (n = 75).
These findings will go some way to filling the current gap in the 9/11 evidence-base regarding the understanding of the long-term health challenges for first responders and recovery workers.
Growing crops that exhibit a high level of competition with weeds increases opportunities to practice integrated weed management and reduce herbicide inputs. The recent development and market dominance of hybrid canola cultivars provides an opportunity to reassess the relative competitive ability of canola cultivars with small-grain cereals. Direct-seeded (no-till) experiments were conducted at five western Canada locations from 2006 to 2008 to compare the competitive ability of canola cultivars vs. small-grain cereals. The relative competitive ability of the species and cultivars was determined by assessing monocot and dicot weed biomass at different times throughout the growing season as well as oat (simulated weed) seed production. Under most conditions, but especially under warm and relatively dry environments, barley cultivars had the greatest relative competitive ability. Rye and triticale were also highly competitive species under most environmental conditions. Canada Prairie Spring Red wheat and Canada Western Red Spring wheat cultivars usually were the least competitive cereal crops, but there were exceptions in some environments. Canola hybrids were more competitive than open-pollinated canola cultivars. More importantly, under cool, low growing degree day conditions, canola hybrids were as competitive as barley, especially with dicot weeds. Under most conditions, hybrid canola growers on the Canadian Prairies are well advised to avoid the additional selection pressure inherent with a second in-crop herbicide application. Combining competitive cultivars of any species with optimal agronomic practices that facilitate crop health will enhance cropping system sustainability and allow growers to extend the life of their valuable herbicide tools.
The objective of this study was to determine if the presence of two acetolactate synthase (ALS)-inhibiting herbicide residues in different Saskatchewan soils would result in additive, synergistic, or antagonistic interactions. This was determined through field trials where herbicides were applied sequentially over the course of 2 yr. The herbicides examined in these experiments were imazamethabenz, flucarbazone, sulfosulfuron, and florasulam, each in combination with imazamox and imazethapyr. The phytotoxicity and persistence of the herbicides in soil was assessed using an oriental mustard root inhibition bioassay. The determination of herbicide interaction was made through the comparison of the experimentally observed values to theoretically expected values derived from a mathematical equation. On the basis of the bioassay analysis, it was found that the herbicide residue combinations resulting from sequentially applied ALS-inhibiting herbicides in the three soils produced additive injury effects rather than synergistic or antagonistic interactions.
Using an oriental mustard root length bioassay, thiencarbazone bioavailability and dissipation in five Saskatchewan soils was investigated under laboratory conditions. Thiencarbazone bioavailability was assessed at 0 to 3.9 µg ai kg−1. Thiencarbazone concentrations corresponding to 50% inhibition (I50 values) obtained from dose-response curves varied from 0.56 to 1.71 µg kg−1. Multiple regression analysis indicated that organic carbon content (P = 0.018) and soil pH (P = 0.017) predicted thiencarbazone bioavailability. Thiencarbazone dissipation was examined in soils incubated at 23 C and moisture content of 85% field capacity. Thiencarbazone half-lives estimated from dissipation curves were 9 to 50 d, and organic carbon content (P = 0.002) and soil pH (P = 0.008) were significant factors affecting thiencarbazone dissipation. Thiencarbazone bioavailability decreases and dissipation rate is slower in Canadian prairie soils of high organic matter content and low soil pH. Because root length of oriental mustard plants also was reduced by ammonium, therefore ammonium-containing or -producing fertilizers can cause false positive results for thiencarbazone soil residues. Canaryseed roots had the same sensitivity to ammonium as oriental mustard roots but were not inhibited by thiencarbazone. Therefore canaryseed root length bioassay was effective in identifying inhibition caused by ammonium toxicity. Use of oriental mustard root and canaryseed root bioassays together can aid in interpreting bioassay results for detection of thiencarbazone residues.
With increasing incidence of glyphosate-resistant weeds worldwide, greater farmer awareness of the importance of glyphosate stewardship and proactive glyphosate-resistance management is needed. A Web-based decision-support tool (http://www.weedtool.com) comprising 10 questions has been developed primarily for farmers in western Canada to assess the relative risk of selection for glyphosate-resistant weeds on a field-by-field basis. We describe the rationale for the questions and how a response to a particular question influences the risk rating. Practices with the greatest risk weighting in western Canadian cropping systems are lack of crop-rotation diversity (growing mainly oilseeds) and a high frequency of glyphosate-resistant crops in the rotation. Three case scenarios are outlined—low, moderate, and high risk of glyphosate-resistance evolution. Based on the overall risk rating, three best-management practices are recommended to reduce the risk of glyphosate resistance in weeds.
Field pea seed from bin cleaning operations stored overwinter on nearby cropland was observed to correlate with weed and crop growth suppression for up to three subsequent years. To explore the phenomenon more explicitly, plant growth suppression trials were undertaken with soil sampled 18 mo apart from two locations that had contained field pea seed residues. Test plant species grown in the residue-affected and nearby residue-free soils were compared in greenhouse experiments. Germination was either fully inhibited or emergence was delayed by more than one week. Dry matter accumulation of test species grown in residue-affected soil was significantly reduced compared to dry matter of these test species grown in residue-free soil (P < 0.0001). Canola and field pea were inhibited more than wheat and green foxtail over both years. Greenhouse trials also revealed that germination of wild oat was inhibited in the residue-affected soils, although wheat and grassy weeds were less suppressed than dicots overall. Significant reductions of weed species diversity and abundance were correlated to residue-affected soils (P < 0.0001) when compared to residue-free soils using multi-response permutations procedures. Germination of wheat and canola seed was inhibited, using aqueous extracts of weathered pea seeds or extracts of the residue-affected soil in bioassays in sterile media. An allelopathic response was proposed to explain the above results, indicating a need for further research on this system. Weed management strategies could be developed with field pea seed residues to provide innovative weed control techniques.
The Interregional Research Project Number 4 (IR-4) Specialty Food Crops Program is a publicly-funded program initiated in 1963 to develop and submit regulatory data to support registration of pest control products for specialty crops. In the early to mid 1990s, nearly 45% of the IR-4 residue projects supported new herbicide registrations for fruits and vegetables with the other 55% devoted to fungicides, insecticides, and nematacides. In 2005, the number of residue projects conducted by IR-4 to support herbicide fruit and vegetable registrations was less than 30%. The three main factors that have contributed to this decline are: fewer herbicides available for registration; product liability concerns; and an increased focus on new, safer, and Reduced Risk Pesticides for insect and disease control. It has been a number of years since a new herbicide has been developed for a major crop that could be extended to specialty food crops. Many of the current IR-4 herbicide projects are with products that have been on the market for 20 or more years. Product liability is a concern because of the high value of many specialty crops relative to the potential market opportunity. In many cases, the registrant requires product performance data before IR-4 can proceed with a residue project. With limited funds for developing these data, many new projects never proceed to the regulatory stage. Although registrants can seek indemnification for some of these uses, it is a complicated often state-specific process. IR-4 has been successful in a number of areas, including the registration of a large numbers of uses through reduced data extrapolations for products such as glyphosate and carfentrazone-ethyl. Additionally, IR-4 submitted the first successful petition establishing an exemption of tolerance for a conventional herbicide (imazamox). Future IR-4 initiatives include collaboration with industry, growers, and academia to develop new herbicide technologies such as plant breeding or transgenic crops and generation of appropriate data to extend those products to specialty food crops. IR-4 will also assist in registering products that can be used on crops that have been selected (or developed through biotechnological approaches) to be tolerant to existing herbicides. Registrants should strongly consider developing herbicides for specialty food crops, with IR-4's assistance, as a means to expand markets and also as a means to extend data protection of their products, as allowed under the Food Quality Protection Act.
Sulfentrazone is a phenyl triazolinone herbicide used for control of certain broadleaf and grass weed species. Sulfentrazone persists in soil and has residual activity beyond the season of application. A laboratory bioassay was developed for the detection of sulfentrazone in soil using root and shoot response of several crops. Shoot length inhibition of sugar beet was found to be the most sensitive and reproducible parameter for measurement of soil-incorporated sulfentrazone. The sugar beet bioassay was then used to examine the effect of soil properties on sulfentrazone phytotoxicity using 10 different Canadian prairie soils. Concentrations corresponding to 50% inhibition (I50 values) were obtained from the dose–response curves constructed for the soils. Sulfentrazone phytotoxicity was strongly correlated to the percentage organic carbon (P = 0.01) and also to percentage clay content (P = 0.05), whereas correlation with soil pH was nonsignificant (P = 0.21). Because sulfentrazone phytotoxicity was found to be soil dependent, the efficacy of sulfentrazone for weed control and sulfentrazone potential carryover injury will vary with soil type in the Canadian prairies.
As a weed, wheat has recently gained greater profile. Determining wheat persistence in cropping systems will facilitate the development of effective volunteer wheat management strategies. In October of 2000, glyphosate-resistant (GR) spring wheat seeds were scattered on plots at eight western Canada sites. From 2001 to 2003, the plots were seeded to a canola–barley–field-pea rotation or a fallow–barley–fallow rotation, with five seeding systems involving seeding dates and soil disturbance levels, and monitored for wheat plant density. Herbicides and tillage (in fallow systems) were used to ensure that no wheat plants produced seed. Seeding systems with greater levels of soil disturbance usually had greater wheat densities. Volunteer wheat densities at 2 (2002) and 3 (2003) yr after seed dispersal were close to zero but still detectable at most locations. At the end of 2003, viable wheat seeds were not detected in the soil seed bank at any location. The majority of wheat seedlings were recruited in the year following seed dispersal (2001) at the in-crop, prespray (PRES) interval. At the PRES interval in 2001, across all locations and treatments, wheat density averaged 2.6 plants m−2. At the preplanting interval (PREP), overall wheat density averaged only 0.2 plants m−2. By restricting density data to include only continuous cropping, low-disturbance direct-seeding (LDS) systems, the latter mean dropped below 0.1 plants m−2. Only at one site were preplanting GR wheat densities sufficient (4.2 plants m−2) to justify a preseeding herbicide treatment in addition to glyphosate in LDS systems. Overall volunteer wheat recruitment at all spring and summer intervals in the continuous cropping rotation in 2001 was 1.7% (3.3 plants m−2). Despite the fact that volunteer wheat has become more common in the central and northern Great Plains, there is little evidence from this study to suggest that its persistence will be a major agronomic problem.