Investigation of pesticide residues level on commonly consumed leafy vegetables picked from the central market in Jeddah, Saudi Arabia.

This study aimed to investigate the presence of pesticide residues in a variety of commonly consumed leafy vegetables, including Grape leaves, Lettuce, Arugula, Spinach, Purslane, Ocimum, Parsley, Jew's mallow, Celery, Coriander, and Mint. A total of 100 samples were collected from the Central Market of Jeddah, Kingdom of Saudi Arabia. Our methodology involved employing the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) extraction method in combination with Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) to analyze a comprehensive database of 237 distinct pesticides. The range for limit of detection (LOD) and limit of quantification (LOQ) of the method were 0.0001 to 0.0014 mg. Kg-1 and 0.0010 to 0.0064 mg. Kg-1 for tested pesticides, respectively. The recoveries were in the range of 70-172.9%, with a relative standard deviation (RSD) of less than 19.0% for all tested pesticides. The results revealed that 60% of the analyzed samples were free from pesticide residues, while 40% exhibited contamination with 17 different pesticide residues. Notably, the most prevalent pesticide detected was Triallate in the Ocimum samples, followed by Metalaxyl in Grape leaves, Mint, and Spinach, and Methomyl in Celery. Approximately 45% of the samples contained pesticide residues that fell below or were equal to the European Union Maximum Residue Levels (EU MRLs), while the remaining 55% exceeded these MRLs. Remarkably, high pesticide concentrations were observed in all Ocimum samples (Triallate, Pyridaben, Hexythiazox, Imidacloprid), 67% of Grape leaves (Metalaxyl, Azoxystrobin, Difenoconazole Isomer), and 40% of Celery (Azoxystrobin, Methomyl). In conclusion, this study sheds light on the contamination levels of commonly consumed domestically produced and purchased leafy vegetables in the Central Market of Jeddah. To ensure food safety and the well-being of consumers, we strongly recommend enhanced scientific assessments and continued monitoring of pesticide usage in agricultural practices.

Evaluating the Ecological Footprint of Landfills: A Framework and Case Study of Fargo, North Dakota.

There is growing interest in better understanding the environmental impacts of landfills and optimizing their operation. Accordingly, we developed a holistic framework to calculate a landfill's Ecological Footprint (EF) and applied that to the Fargo, North Dakota, landfill. Parallelly, the carbon footprint and biocapacity of the landfill were calculated. We calculated the EF for six scenarios (i.e., cropland, grazing land, marine land, inland fishing ground, forest land, and built land as land types) and six operational strategies typical for landfills. Operational strategies were selected based on the variations of landfill equipment, the gas collection system, efficiency, the occurrence of fugitive emissions, and flaring. The annual EF values range from 124 to 213,717 global hectares depending on land type and operational strategy. Carbon footprints constituted 28.01-99.98% of total EF, mainly driven by fugitive emissions and landfill equipment. For example, each percent increase in Fargo landfill's fugitive emissions caused the carbon footprint to rise by 2130 global hectares (4460 tons CO2e). While the landfill has biocapacity as grazing grass in open spaces, it remains unused/inaccessible. By leveraging the EF framework for landfills, operators can identify the primary elements contributing to a landfill's environmental impact, thereby minimizing it.

Impacts of the COVID-19 pandemic on landfilling and recycling in the city of Fargo, North Dakota, USA.

The COVID-19 pandemic impacted different aspects of human lifestyle, including waste generation and management. The landfilled and recycled waste volume from the City of Fargo's annual solid waste report between 2019 and 2021 was critically analyzed to understand these impacts. The analysis showed a 4.5% increase in the residential waste volume in 2020 compared to 2019 and 2021, suggesting a pandemic-induced lockdown effect. The monthly residential waste volume was approximately 5-15% greater during the mandatory quarantine period (April - November 2020) than in 2019 and 2021. Commercial waste volume decreased by 12% during 2020 and then sharply increased in 2021 as commercial facilities reopened. The total recycling volume increased slightly by 2.5% in 2020 compared to 2019 and 2021. Cardboard recycling showed a 5.8% increase in 2020 from 2019 and a 13% increase in 2021 compared to 2020. This was presumably caused by the reliance on online shopping during the pandemic and becoming habituated to online shopping. The COVID-19 pandemic did not significantly impact other classes of recycled waste volumes. In summary, COVID-19 affected landfilling and recycling in different capacities in the City of Fargo. The data will contribute to the global understanding of the impact of COVID-19 on solid waste management practices.Implications: The COVID-19 pandemic impacted waste generation and management. In Fargo, USA, the monthly residential waste volume increased by up to 15% during the mandatory quarantine period in 2020 compared to the same period in 2019 and 2021. Conversely, the monthly commercial waste volume decreased during the mandatory quarantine period in 2020. The commercial waste volume increased in 2021 as commercial activities became normal. The cardboard recycling increased significantly because people became used to online shopping during the lockdown, and the practice continues. The findings will contribute to the global understanding of the impact of COVID-19 on solid waste management practices.

Farm Machinery Injuries: A Retrospective Analysis of Admissions at a Level I Trauma Center in North Dakota.

OBJECTIVES: The purpose of the present study was to characterize the incidence, injury characteristics, and outcomes of patients presented to a Level I adult trauma center in Fargo, North Dakota, with farm machinery injuries (FMI). METHODS: We performed a retrospective review of the trauma registry of Sanford Medical Center Fargo (SMCF) between January 2010 and December 2020. We compared admission characteristics of FMI admissions to non-FMI admissions, identified the types of machinery that are most commonly associated with FMI, and described the nature of these injuries by severity, anatomical site, type, age, sex, and length of stay (LoS). Injury severity was evaluated using Injury Severity Score (ISS). RESULTS: Findings indicated that FMI admissions had a higher mean ISS, longer ICU LoS, and a higher mortality rate than non-FMI admissions. The leading cause of fatal and non-fatal FMI in this region are tractors. Males experience 91.2% of tractor injuries, and individuals 65 and over account for nearly 53% of all tractor injuries (n = 18). Males accounted for all deaths, tractor and otherwise. The "other machinery" category was the second most common category and accounted for 50% of female patients. Additionally, 24.5% of all FMI are related to machine maintenance. CONCLUSION: The findings from this study indicate that FMI injuries represent a significant problem in the upper Midwest. Older, male farm workers experience a higher incidence of tractor-related injuries, and all tractor-related deaths occurred in individuals 65 years of age and older. These results underscore the need for further investigation into aging-related farm safety issues.

FARGO-360: a multi-disciplinary survey of practice and perspectives on provision of care for patients with frailty presenting with gynecological cancers in the UK and Ireland.

OBJECTIVES: Frailty has been associated with worse cancer-related outcomes for people with gynecological cancers. However, the lack of clear guidance on how to assess and modify frailty prior to instigating active treatments has the potential to lead to large variations in practice and outcomes. This study aimed to evaluate current practice and perspectives of healthcare practitioners on the provision of care for patients with frailty and a gynecological cancer. METHODS: Data were collected via a questionnaire-based survey distributed by the Audit and Research in Gynecological Oncology (ARGO) collaborative to healthcare professionals who identified as working with patients with gynecological malignancies in the United Kingdom (UK) or Ireland. Study data were collected using REDCap software hosted at the University of Manchester. Responses were collected over a 16 week period between January and April 2021. RESULTS: A total of 206 healthcare professionals (30 anesthetists (14.6%), 30 pre-operative nurses (14.6%), 51 surgeons (24.8%), 34 cancer specialist nurses (16.5%), 21 medical/clinical oncologists (10.2%), 25 physiotherapists/occupational therapists (12.1%) and 15 dieticians (7.3%)) completed the survey. The respondents worked at 19 hospital trusts across the UK and Ireland. Frailty scoring was not routinely performed in 63% of care settings, yet the majority of practitioners reported modifying their practice when providing and deciding on care for patients with frailty. Only 16% of organizations surveyed had a dedicated pathway for assessment and management of patients with frailty. A total of 37% of respondents reported access to prehabilitation services, 79% to enhanced recovery, and 27% to community rehabilitation teams. CONCLUSION: Practitioners from all groups surveyed considered that appropriate training, dedicated pathways for optimization, frailty specific performance indicators and evidence that frailty scoring had an impact on clinical outcomes and patient experience could all help to improve care for frail patients.

Effects of Soil Type, Temperature, and Moisture on Development of Fusarium Root Rot of Soybean by Fusarium solani (FSSC 11) and Fusarium tricinctum.

Fusarium solani FSSC 11 and F. tricinctum are important root rot pathogens of soybean in North Dakota. The roles of soil type, temperature, and moisture in disease development by both species are poorly documented. To assess the effect of soil type on disease, three types of soil (Glyndon sandy loam, La Prairie silt loam, and Fargo clay) that represent soils of the soybean production region in the Red River Valley were examined in greenhouse, microplot, and growth chamber studies. Disease incidence and lesion length on roots were evaluated at growth stages V3 and R6. Soil type significantly affected disease development, with higher severity in the lighter soils of Glyndon sandy loam and La Prairie silt loam compared with Fargo clay. Soil type also interacted with Fusarium species, in which the maximum severity was observed in Glyndon sandy loam for F. solani, and in La Prairie silt loam for F. tricinctum. In addition, the cumulative effects of soil type, temperature, and soil moisture were tested in a growth chamber. Emergence and disease on seedlings were evaluated at growth stage V3. Significant reductions in emergence occurred at 10°C in treatments with F. solani and F. tricinctum, but there was no significant difference among the three soils. Infection was visible at temperatures of 10 to 20°C for F. solani and 15 to 20°C for F. tricinctum. F. solani caused the greatest infection at 20°C in Glyndon sandy loam, while it was at 15°C in La Prairie silt loam for F. tricinctum. The isolates of the two Fusarium species caused root rot in soil moisture ranging from 20 to 100% water holding capacity (WHC). The greatest reduction in emergence caused by the Fusarium spp. was observed at 80% WHC in silt loam and clay soils and 40% WHC in sandy loam soil, when compared with the same WHC in noninfested soils. Ranges of soil moisture causing infection were negatively correlated with temperature. At the lower temperature there was a broader range of soil moistures resulting in infection compared with higher temperatures. At 18°C, most infection occurred at soil moistures of 20 to 80% WHC, while it was 40 to 80% WHC at 28°C. Disease caused by F. solani was favored by a temperature of 18°C with high soil moisture (60 to 80% WHC) or 28°C with low soil moisture (20 to 40% WHC), while F. tricinctum was favored by cooler temperature and lower soil moisture.

Health-Related Quality of Life and Angina in Fractional Flow Reserve- Versus Angiography-Guided Coronary Artery Bypass Grafting: FARGO Trial (Fractional Flow Reserve Versus Angiography Randomization for Graft Optimization).

BACKGROUND: In coronary artery bypass grafting (CABG), the use of fractional flow reserve (FFR) is insufficiently investigated. Stenosis assessment usually relies on visual estimates of lesion severity. This study evaluated health-related quality of life (HRQoL) and angina after FFR- versus angiography-guided CABG. METHODS: One hundred patients referred for CABG were randomized to FFR- or angiography-guided CABG. In the FFR group, lesions with FFR>0.80 were deferred, while the surgeon was blinded to the FFR values in the angiography group. Before and 6 months after CABG, HRQoL was assessed by the health state classifier EQ-5D of the EuroQoL 5-level instrument and angina status based on the Canadian Cardiovascular Society classification system were registered. RESULTS: Six-month angiography included FFR evaluations of deferred lesions. In total, completed EQ-5D of the EuroQoL 5-level instrument questionnaires were available in 86 patients (43 in the FFR versus 43 in the angiography-guided group). HRQoL was significantly improved and angina significantly decreased from baseline to 6 months after CABG with no difference between the randomization groups. Graft failure rates and clinical outcomes were similar in both groups. Patients with graft failure or FFR<0.80 of the previous deferred lesions had significantly lower visual analogue scale scores (78.7±14.2 versus 86.8±14.7, P=0.004) and more angina compared with patients without graft failure or FFR≥0.80 at 6-month follow-up. CONCLUSIONS: FFR- versus angiography-guided CABG demonstrated similar improvements in HRQoL and angina 6 months after CABG. Graft failure or low FFR in deferred lesions were associated with low HRQoL and angina. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02477371.

Longitudinal study on the detection of Clostridioides difficile at the Fargo Veteran Affairs Community Living Center.

Our study used C Diff Banana Broth to evaluate the occurrence of positive Clostridioides difficile spores in new and preexisting hospital rooms. C difficile incidence was 5.5%. Analysis using multiple linear regression found that rooms with contact precautions in place were significant predictors of a positive sample (P ≤ .001). Room occupancy was not a significant predictor (P = .544). Thus it could be interpreted that the environment can be a significant carrier for C difficile.

Can herbicide safeners allow selective control of weedy rice infesting rice crops?

BACKGROUND: Rice is a major field crop of paramount importance for global food security. However, the increased adoption of more profitable and resource-efficient direct-seeded rice (DSR) systems has contributed to greater weed infestations, including weedy rice, which has become a severe problem in several Asian regions. In this study we have developed a conceptually novel method to protect rice plants at high doses of clomazone and triallate. RESULTS: The insecticide phorate applied to rice seeds provided a substantial level of protection against the herbicides clomazone or triallate. A quantity of 15 kg phorate ha-1 significantly increased the LD50 values, which were more than twofold greater than for rice plants treated only with clomazone. A quantity of 20 kg phorate ha-1 in combination with 2000 g triallate ha-1 safened rice plants (80% survival) with LD50 >3.4-fold greater than in phorate-untreated rice. Weed control efficacy was not lowered by the presence of phorate-treated rice seeds. CONCLUSION: Weedy rice is one of the most damaging global weeds and a major threat to DSR systems. In this study we have developed a proof-of-concept method to allow selective weedy rice control in rice crops. We call for herbicide discovery programmes and research to identify candidate safener and herbicide combinations to achieve selective herbicide control of weedy rice and alleviate weed infestations in global rice crops. © 2016 Society of Chemical Industry.

Cross-resistance to prosulfocarb and triallate in pyroxasulfone-resistant Lolium rigidum.

BACKGROUND: Plants can rapidly evolve resistance to herbicide in response to repeated selection. This study focuses on cross-resistance patterns observed in Lolium rigidum following pyroxasulfone recurrent selection. RESULTS: The parental MR (multiresistant) population following four generations of pyroxasulfone recurrent selection evolved cross-resistance to prosulfocarb and triallate. At the recommended label rate of prosulfocarb or triallate (2000 g ha(-1) ), the progeny selected four times with pyroxasulfone (MR4) displayed 58 and 35% plant survival respectively. One additional cycle of prosulfocarb selection increased the resistance level to both prosulfocarb and triallate in the population MR4-P1. Prosulfocarb resistance is yet to be reported in L. rigidum field populations. CONCLUSIONS: This study suggests that L. rigidum plants can rapidly evolve cross-resistance to several wheat-selective herbicides under recurrent selection of a single mode of action. Weed populations displaying broad-spectrum cross-resistance to several herbicide modes of action are increasing in frequency in intensive world agriculture. Proactive and integrated measures for resistance management need to be developed globally on appropriate herbicide use in crop rotations.

Volatilization modeling of two herbicides from soil in a wind tunnel experiment under varying humidity conditions.

Volatilization of pesticides from the bare soil surface is drastically reduced when the soil is under dry conditions (i.e., water content lower than the permanent wilting point). This effect is caused by the hydrated mineral surfaces that become available as additional sorption sites under dry conditions. However, established volatilization models do not explicitly consider the hydrated mineral surfaces as an independent sorption compartment and cannot correctly cover the moisture effect on volatilization. Here we integrated the existing mechanistic understanding of sorption of organic compounds to mineral surfaces and its dependence on the hydration status into a simple volatilization model. The resulting model was tested with reported experimental data for two herbicides from a wind tunnel experiment under various well-defined humidity conditions. The required equilibrium sorption coefficients of triallate and trifluralin to the mineral surfaces, K(min/air), at 60% relative humidity were fitted to experimental data and extrapolated to other humidity conditions. The model captures the general trend of the volatilization in different humidity scenarios. The results reveal that it is essential to have high quality input data for K(min/air), the available specific surface area (SSA), the penetration depth of the applied pesticide solution, and the humidity conditions in the soil. The model approach presented here in combination with an improved description of the humidity conditions under dry conditions can be integrated into existing volatilization models that already work well for humid conditions but still lack the mechanistically based description of the volatilization process under dry conditions.

Simulating herbicide volatilization from bare soil affected by atmospheric conditions and limited solubility in water.

A numerical model that simulates pesticide fate was developed to predictthe behavior of triallate after application to a field soil. The model has options that allow water and/ or heat transport and can limit simulated aqueous-phase concentrations to triallate solubility in water. Several methods for describing the volatilization boundary condition were tested to assess the accuracy in predicting the volatilization rate, including an approach that requires no atmospheric information and an approach that couples soil and atmospheric processes. Four scenarios were constructed and simulated, to compare with measured volatilization rates. The peak measured volatilization rate (168 g ha(-1) h(-1)) was most accurately predicted with the scenario that included the most complex model (100 g ha(-1) h(-1)). The simplest model overpredicted the peak rate (251 g ha(-1) h(-1)), and the others underpredicted the peak rate (16-67 g ha(-1) h(-1)). The simulations that limited aqueous solubility provided relatively similar values for the total emissions (21-37% of applied triallate), indicating that simplified models may compare well with measurements (31% of applied). A prospective simulation over a period of 100 days showed that applying triallate to the soil surface would ultimately lead to atmospheric emissions of 80% of the applied material with 6% remaining in soil. Incorporating triallate to a depth of 10 cm would reduce emissions to less than 5% and lead to 41% remaining in soil.

Measuring herbicide volatilization from bare soil.

A field experiment was conducted to measure surface dissipation and volatilization of the herbicide triallate after application to bare soil using micrometeorological, chamber, and soil-loss methods. The volatilization rate was measured continuously for 6.5 days and the range in the daily peak values for the integrated horizontal flux method was from 32.4 (day 5) to 235.2 g ha(-1) d(-1) (day 1), for the theoretical profile shape method was from 31.5 to 213.0 g ha(-1) d(-1), and for the flux chamber was from 15.7 to 47.8 g ha(-1) d(-1). Soil samples were taken within 30 min after application and the measured mass of triallate was 8.75 kg ha(-1). The measured triallate mass in the soil at the end of the experiment was approximately 6 kg ha(-1). The triallate dissipation rate, obtained by soil sampling, was approximately 334 g ha(-1) d(-1) (98 g d(-1)) and the average rate of volatilization was 361 g ha(-1) d(-1). Soil sampling at the end of the experiment showed that approximately 31% (0.803 kg/2.56 kg) of the triallate mass was lost from the soil. Significant volatilization of triallate is possible when applied directly to the soil surface without incorporation.

Chlorinated herbicide (triallate) dehalogenation by iron powder.

The reductive degradation of a chlorinated herbicide by iron powder was investigated at lab scale. The studied substrate was triallate (S-2,3,3-trichloroallyl di-isopropyl thiocarbamate) which contains a trichloroethylene moiety potentially reducible by zero-valent iron. Degradation reactions were carried out in batch, at 25 degrees C, in the absence of oxygen, by contacting electrolytic iron powder (size range: 20-50 microm) with a triallate aqueous solution (2.5 mgl(-1)). Herbicide decay, corresponding evolutions of TOC, TOX and chloride ion release were regularly monitored throughout the reactions. Furthermore, the main degradation by-products were identified by HPLC/MS. The results showed that, after 5 days, herbicide degradation extent was about 97% and that the reaction proceeded through the formation of a dechlorinated alkyne by-product (S-2-propinyl di-isopropyl thiocarbamate) resulting from the complete dechlorination of triallate. The subsequent reduction of such an alkyne intermediate gave S-allyl di-isopropyl thiocarbamate as main end by-product. The identified by-products suggested that dechlorination took place mainly via reductive beta-elimination. However, as traces of dichloroallyl di-isopropyl thiocarbamate were also detected, a role, although minor, was assigned even to hydrogenolysis in the overall dechlorination process.

A cross-sectional study of triallate exposure and neurological health among workers at a pesticide manufacturing and formulating facility.

AIMS: To evaluate the relation between an indicator of cumulative exposure to triallate and selected measures of neurological function, including nerve conduction, the prevalence of certain neurological deficits as determined by a medical examination, and vibration perception threshold testing in workers at a pesticide manufacturing plant. METHODS: Subjects were 50 workers with high estimated triallate exposure ("high triallate" group) and 50 workers with no or low triallate exposure ("no/low triallate" group). Industrial hygienists used existing work histories and personal knowledge of plant operations to develop a triallate score. In-person interviews elicited information on past medical history and on occupational and non-occupational exposures. A neurologist carried out nerve conduction tests of the sural and the peroneal nerves, a standardised neurological examination, and vibration sensation testing. RESULTS: Differences between the high and the no/low triallate groups were minimal for all but one of the six nerve conduction tests, for the prevalence of neurological abnormalities, and for vibration sensation perception. The high triallate group had lower mean sural nerve peak amplitude than the no/low triallate group (11.7 v 15.2 microV, p = 0.03). This difference was reduced when adjusted for other potential risk factors (12.5 v 14.5 microV, p = 0.25) and was not associated with cumulative triallate score. We also noted several associations between factors other than triallate and nerve conduction measures. CONCLUSION: The results were consistent with the absence of an association between triallate and measures of neurological function.

Body mass index and bromoxynil exposure in a sample of rural residents during spring herbicide application.

Bromoxynil (3,5-dibromo-4-hydroxybenzonitrile), a phenolic herbicide, is widely used in production of cereals and other crops. Little is known, however, about bromoxynil exposure in humans. Results of previous research suggest a longer residence time in the body for bromoxynil compared to phenoxy herbicides [e.g., (2,4-dichlorophenoxy)acetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA)] and that bromoxynil would tend to partition into fatty tissue more so than 2,4-D. In previous research, body mass index (BMI) was found to be an independent predictor of plasma concentrations of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), the persistent lipophilic metabolite of the chlorinated pesticide bis(4-chlorophenyl)-1,1,1-trichloroethane (DDT). As part of the Prairie Ecosystem Study, gas chromatography/mass spectrometry analysis was used to measure concentrations of bromoxynil and seven other herbicides (2,4-D, dicamba, fenoxaprop, MCPA, ethalfluralin, triallate, and trifluralin) in plasma from residents (104 men, 88 women, 24 youths age 12-17 yr) of a cereal-producing region in Saskatchewan, Canada, during spring herbicide application, 1996. Multiple logistic regression analysis was used to explore whether BMI predicted detection of bromoxynil in plasma from the adults. The prevalence of detection (detection limits: 2-50 microg/L) was markedly higher for bromoxynil (men, 44.2%; women, 14.8%; youths, 20.8%) compared to each of the other herbicides including 2,4-D (men, 16.5%; women, 3.4%; youths, 12.5%) and MCPA (men, 6.8%; women, 1.1%; youths, 4.2%), although bromoxynil is commonly formulated or tank mixed with these herbicides. In the multiple logistic regression analysis, the variables BMI, exposure group [bromoxynil applicators, non-applicator family members of bromoxynil applicators, all others (reference group)], and days elapsed since the last use of bromoxynil were found to be independent predictors of detection of bromoxynil, while age, gender, and farm residency were not statistically significant. With adjustment for exposure group [bromoxynil applicators: odds ratio (OR = 24.30, 95% confidence interval (CI) = 9.59-61.58; nonapplicator family members of bromoxynil applicators: OR = 3.53, 95% CI = 1.19-10.44; all others (reference group)], the OR for detection of bromoxynil was 2.35 (95% CI = 0.87-6.33) for participants in the middle (25.53-29.00 kg/m2) tertile (men: OR = 2.85, 95% CI = 0.75-10.82; women: OR = 1.63, 95% CI = 0.36-7.40) of BMI and 4.01 (95% CI = 1.46-11.03) for participants in the highest (> 29.00 kg/m2) tertile (men: OR = 4.67, 95% CI = 1.17-18.58; women: OR = 2.20, 95% CI = 0.44-10.99) with participants in the lowest (< 25.53 kg/m2) tertile as the reference group. Similar ORs were observed for BMI with adjustment for days elapsed since the last use of bromoxynil. In conclusion, further research is needed to investigate whether adiposity is an important modifying factor for persistence of bromoxynil in the body.

A review of the genotoxicity of triallate.

Triallate is a selective herbicidal chemical used for control of wild oats in wheat. It has an extensive genotoxicity database that includes a variety of in vitro and in vivo studies. The chemical has produced mixed results in in vitro assay systems. It was genotoxic in bacterial mutation Ames assays, predominantly in Salmonella typhimurium strains TA100 and TA1535 in the presence of S9. Weaker responses have been observed in TA100 and TA1535 in the absence of S9. Mixed results have been observed in strain TA98, whereas no genotoxicity has been observed in strains TA1537 and TA1538. The presence and absence of S9 and its source seem to play a role in the bacterial response to the chemical. There have also been conflicting results in other test systems using other bacterial genera, yeast, and mammalian cells. Chromosome effects assays (sister-chromatid exchange and cytogenetics assays) have produced mixed results with S9 but no genotoxicity without S9. Triallate has not produced any genotoxicity in in vitro DNA damage or unscheduled DNA synthesis assays using EUE cells, human lymphocytes, and rat and mouse hepatocytes. In a series of in vivo genotoxicity assays (cytogenetics, micronucleus, dominant lethal, and unscheduled DNA synthesis), there has been no indication of any adverse genotoxic effect. Metabolism data indicate that the probable explanation for the differences observed between the in vitro studies with S9 and without S9 and between the in vitro and the in vivo studies is the production of a mutagenic intermediate in vitro at high doses of triallate is expected to be at most only transiently present in in vivo studies. The weight of evidence strongly suggests that triallate is not likely to exert mutagenic activity in vivo due to toxicokinetics and metabolic processes leading to detoxification.

Two recessive gene inheritance for triallate resistance in Avena fatua L.

Extensive use of the preemergence herbicide triallate over the last three decades has selected for resistant (R) Avena fatua L. populations in several areas of the United States and Canada. R plants are also cross-resistant to the unrelated pyrazolium herbicide difenzoquat. We made reciprocal crosses between inbred R and susceptible (S) lines to determine the genetic basis of triallate resistance. Seeds from parental lines and F(2) populations were treated with soil applications of 0.275, 0.55, or 1.1 kg/ha triallate in the greenhouse and plant heights recorded after 37 days. Surviving F(2) plants were selfed and the resulting F(3) families were screened with 1.1 kg/ha triallate. In the F(2) populations, assortment of S and R phenotypes fit a 15:1 segregation ratio, suggesting that resistance was controlled by the two independently segregating recessive genes TRR1 and TRR2. None of the 912 F(3) progeny from 51 R F(2) individuals was susceptible to triallate treatment, further supporting a two-gene mode of inheritance. There was a possible maternal effect on susceptibility at the highest triallate rate tested.

Environmental concentrations of agricultural herbicides: 2,4-d and triallate.

The herbicides 2,4-D (2,4-dichlorophenoxyacetic acid) and triallate [S-2,3,3-trichloroallyl di-isopropyl(thiocarbamate)] are extensively used to control broadleaf and wild oat (respectively) weed infestations in Canadian cereal crops. In 1990, for example, more than 3.8 million kg of 2,4-D and 2.7 million kg of triallate were applied in the three prairie provinces (Alberta, Saskatchewan, and Manitoba). Maximum air concentrations of these two herbicides during the summers of 1989 and 1990 near Regina, Saskatchewan, were 3.90 ng m(-3) (2,4-D) and 60.04 ng m(-3) (triallate). Concentrations of these two herbicides were also measured in bulk atmospheric deposition (wet plus dry) and in farm pond water and associated surface film. Maximum measured levels of 2,4-D were 3550 ng m(-2) d(-1) (bulk deposition), 332 ng m(-2) (surface film), and 290 ng L(-1) (pond water). Maximum levels of triallate were 2300 ng m(-2) d(-1) (bulk deposition), 212 ng m(-2) (surface film), and 500 ng L(-1) (pond water). The highest quantities of the herbicides tended to be found during or immediately after the time of regional application. The movement of the herbicides in the environment will be discussed in relation to the four matrices studied.

Volatilisation of triallate as affected by soil texture and air velocity.

The rate of volatilisation of the formulated herbicide triallate was investigated in a wind tunnel under controlled wind-speed conditions. An experimental set-up is described which allows the monitoring of wind speed (w.s.), soil-water content, and the temperature of air and soil. A system controlling soil-water content is also described. The influence of air velocity and soil texture was investigated measuring the cumulative volatilisation losses of triallate from soil. The herbicide volatilisation losses after application ranged from 40% at 3 m/s to 53% at 9 m/s for loam soil and from 60% at 3 m/s to 73% at 9 m/s for sandy soil.