Pesticide Exposure - HH-RA.org

Ziska, 2020

Ziska, Lewis H.; “Climate Change and the Herbicide Paradigm: Visiting the Future;” Agronomy, 2020, 10(12); DOI: 10.3390/agronomy10121953.

ABSTRACT:

Weeds are recognized globally as a major constraint to crop production and food security. In recent decades, that constraint has been minimized through the extensive use of herbicides in conjunction with genetically modified resistant crops. However, as is becoming evident, such a stratagem is resulting in evolutionary selection for widespread herbicide resistance and the need for a reformation of current practices regarding weed management. Whereas such a need is recognized within the traditional auspices of weed science, it is also imperative to include emerging evidence that rising levels of carbon dioxide (CO2) and climatic shifts will impose additional selection pressures that will, in turn, affect herbicide efficacy. The goal of the current perspective is to provide historical context of herbicide use, outline the biological basis for CO2/climate impacts on weed biology, and address the need to integrate this information to provide a long-term sustainable paradigm for weed management. FULL TEXT

Vilà et al., 2021

Vilà, Montserrat, Beaury, Evelyn M., Blumenthal, Dana M., Bradley, Bethany A., Early, Regan, Laginhas, Brittany B., Trillo, Alejandro, Dukes, Jeffrey S., Sorte, Cascade J. B., & Ibáñez, Inés; “Understanding the combined impacts of weeds and climate change on crops;” Environmental Research Letters, 2021, 16(3); DOI: 10.1088/1748-9326/abe14b.

ABSTRACT:

Crops worldwide are simultaneously affected by weeds, which reduce yield, and by climate change, which can negatively or positively affect both crop and weed species. While the individual effects of environmental change and of weeds on crop yield have been assessed, the combined effects have not been broadly characterized. To explore the simultaneous impacts of weeds with changes in climate-related environmental conditions on future food production, we conducted a meta-analysis of 171 observations measuring the individual and combined effects of weeds and elevated CO2, drought or warming on 23 crop species. The combined effect of weeds and environmental change tended to be additive. On average, weeds reduced crop yield by 28%, a value that was not significantly different from the simultaneous effect of weeds and environmental change (27%), due to increased variability when acting together. The negative effect of weeds on crop yield was mitigated by elevated CO2 and warming, but added to the negative effect of drought. The impact of weeds with environmental change was also dependent on the photosynthetic pathway of the weed/crop pair and on crop identity. Native and non-native weeds had similarly negative effects on yield, with or without environmental change. Weed impact with environmental change was also independent of whether the crop was infested with a single or multiple weed species. Since weed impacts remain negative under environmental change, our results highlight the need to evaluate the efficacy of different weed management practices under climate change. Understanding that the effects of environmental change and weeds are, on average, additive brings us closer to developing useful forecasts of future crop performance. FULL TEXT

Schulz et al., 2021

Schulz, R., Bub, S., Petschick, L. L., Stehle, S., & Wolfram, J.; “Applied pesticide toxicity shifts toward plants and invertebrates, even in GM crops;” Science, 2021, 372(6537), 81-84; DOI: 10.1126/science.abe1148.

ABSTRACT:

Pesticide impacts are usually discussed in the context of applied amounts while disregarding the large but environmentally relevant variations in substance-specific toxicity. Here, we systemically interpret changes in the use of 381 pesticides over 25 years by considering 1591 substance-specific acute toxicity threshold values for eight nontarget species groups. We find that the toxicity of applied insecticides to aquatic invertebrates and pollinators has increased considerably—in sharp contrast to the applied amount—and that this increase has been driven by highly toxic pyrethroids and neonicotinoids, respectively. We also report increasing applied toxicity to aquatic invertebrates and pollinators in genetically modified (GM) corn and to terrestrial plants in herbicide-tolerant soybeans since approximately 2010. Our results challenge the claims of a decrease in the environmental impacts of pesticide use. FULL TEXT

Nolan et al., 1984

Nolan, R. J., Rick, D. L., Freshour, N. L., & Saunders, J. H.; “Chlorpyrifos: Pharmacokinetics in human volunteers;” Toxicology and Applied Pharmacology, 1984, 73(1), 8-15; DOI: 10.1016/0041-008x(84)90046-2.

ABSTRACT:

The kinetics of chlorpyrifos, an organophosphorothioate insecticide, and its principal metabolite, 3,5,6-trichloro-2-pyridinol (3,5,6-TCP), were investigated in six healthy male volunteers given a single 0.5 mg/kg po and, 2 or more weeks later, a 0.5 or 5.0 mg/kg dermal dose of chlorpyrifos. No signs or symptoms of toxicity or changes in erythrocyte cholinesterase were observed. Plasma cholinesterase was depressed to 15% of predose levels by the 0.5 mg/kg po dose but was essentially unchanged following the 5.0 mg/kg dermal dose. Blood chlorpyrifos concentrations were extremely low (less than 30 ng/ml), and no unchanged chlorpyrifos was found in the urine following either route of administration. Mean blood 3,5,6-TCP concentrations peaked at 0.93 micrograms/ml 6 hr after ingestion of the oral dose and at 0.063 micrograms/ml 24 hr after the 5.0 mg/kg dermal dose. 3,5,6-TCP was cleared from the blood and eliminated in the urine with a half-life of 27 hr following both the po and dermal doses. An average of 70% of the po dose but less than 3% of the dermal dose was excreted in the urine as 3,5,6-TCP; thus only a small fraction of the dermally applied chlorpyrifos was absorbed. Chlorpyrifos and its principal metabolite were rapidly eliminated and therefore have a low potential to accumulate in man on repeated exposures. Based on these data, blood and/or urinary 3,5,6-TCP concentrations could be used to quantify the amount of chlorpyrifos absorbed under actual use conditions.

Chester, 1993

Chester, G.; “Evaluation of agricultural worker exposure to, and absorption of, pesticides;” Annals of Occupational Hygeine, 1993, 37(5), 509-523; DOI: 10.1093/annhyg/37.5.509.

ABSTRACT:

The evaluation of the occupational exposure of agricultural workers to pesticides is an integral part of the risk assessment for product safety and regulatory purposes. At present, there is no internationally accepted, harmonized approach to this exposure evaluation. This paper reviews the currently available methods for the measurement of exposure to, and absorption of, pesticides by workers involved in their use and in associated agricultural activities. Biological monitoring is recommended as the most precise means of estimating the absorbed dose of a pesticide, particularly if supported by human metabolism and pharmacokinetic data. A ‘whole-body’ sampling method is recommended for the measurement of dermal exposure. For concurrent exposure and biological monitoring a refined ‘whole-body’ method is recommended which involves the use of clothing representing that which workers normally wear under the prevailing conditions. A personal air sampling method is recommended for the measurement of inhalation exposure, to collect the ‘inspirable’ fraction (and/or, where necessary, vapour component) of pesticide. These ambient exposure monitoring methods may be conducted simultaneously with biological monitoring. Guidelines are proposed for the conduct of field studies to evaluate exposure to, and absorption of, pesticides to satisfy the requirements of regulatory authority and other organization

Henderson et al., 1993

Henderson, P. T., Brouwer, D. H., Opdam, J. J., Stevenson, H., & Stouten, J. T.; “Risk assessment for worker exposure to agricultural pesticides: review of a workshop;” Annals of Occupational Hygeine, 1993, 37(5), 499-507; DOI: 10.1093/annhyg/37.5.499.

INTRODUCTION:

Pesticides are unusual among occupational chemical hazards, because they are designed to injure or to kill living organisms and are intrinsically toxic. Ideally they would be non-injurious to non-target organisms including man, but most are not highly selective. Therefore, their use should be regulated so that the health and safety of agricultural workers are assured. The key question is: “Are actual exposures safe?” The confidence with which this question can be answered depends on the knowledge of the toxicological properties of the pesticide followed by an assessment of the exposure that may be considered safe. Toxicological evaluation derives the ‘no observed-adverse-effect-levels’ (NOAEL) from experimental studies. The actual exposure must also be known. Comparing this with the NOAEL gives an insight to the risks experienced by the workers. There are several ways to estimate or assess exposure of the field worker. For the levels of exposure many factors are important, including physico-chemical properties of the pesticide, agricultural conditions, working procedure and environmental conditions. The central theme of the present Workshop was to achieve consensus about the optimum approach to:
—measurement of exposure of the agricultural worker, in which both ‘external’ and ‘internal’ exposure, in particular the role of biological monitoring, is considered;

—predictive exposure modelling;

—risk assessment and risk management of occupational exposure to pesticides.
Therefore four papers which follow this review were prepared. During the workshop, which was attended by 28 invited experts (see the List of Participants at the end of this review), the manuscripts were presented and each was critically reviewed by two or three invited respondents. This was followed by in-depth discussions. The present review summarizes the workshop discussions on the different subjects. The various recommendations and proposals that were presented, will be considered as starting points for deriving a harmonized approach to exposure and risk assessment.

Ziska, 2016

Ziska, Lewis H.; “The role of climate change and increasing atmospheric carbon dioxide on weed management: Herbicide efficacy;” Agriculture, Ecosystems & Environment, 2016, 231, 304-309; DOI: 10.1016/j.agee.2016.07.014.

ABSTRACT: Rising concentrations of carbon dioxide [CO₂] and a changing climate will almost certainly affect weed biology and demographics with consequences for crop productivity. The extent of such consequences could be minimal if weed management, particularly the widespread and effective use of herbicides, minimizes any future risk; but, such an outcome assumes that [CO₂] or climate change will not affect herbicide efficacy per se. Is this a fair assumption? While additional data are greatly desired, there is sufficient information currently available to begin an initial assessment of both the physical and biological constraints likely to occur before, during and following herbicide application. The assessment provided here, while preliminary, reviews a number of physical and biological interactions that are likely, overall, to significantly reduce herbicide efficacy. These interactions can range from climatic extremes that influence spray coverage and field access to direct effects of [CO₂] or temperature on plant biochemistry and morphology. Identification of these mechanisms will be essential to both understand and strengthen weed management strategies associated with rising levels of [CO₂] in the context of an uncertain and rapidly changing climate.

Ziska, 2016

Ziska, Lewis H.; “The role of climate change and increasing atmospheric carbon dioxide on weed management: Herbicide efficacy;” Agriculture, Ecosystems & Environment, 2016, 231, 304-309; DOI: 10.1016/j.agee.2016.07.014.

ABSTRACT: Rising concentrations of carbon dioxide [CO₂] and a changing climate will almost certainly affect weed biology and demographics with consequences for crop productivity. The extent of such consequences could be minimal if weed management, particularly the widespread and effective use of herbicides, minimizes any future risk; but, such an outcome assumes that [CO₂] or climate change will not affect herbicide efficacy per se. Is this a fair assumption? While additional data are greatly desired, there is sufficient information currently available to begin an initial assessment of both the physical and biological constraints likely to occur before, during and following herbicide application. The assessment provided here, while preliminary, reviews a number of physical and biological interactions that are likely, overall, to significantly reduce herbicide efficacy. These interactions can range from climatic extremes that influence spray coverage and field access to direct effects of [CO₂] or temperature on plant biochemistry and morphology. Identification of these mechanisms will be essential to both understand and strengthen weed management strategies associated with rising levels of [CO₂] in the context of an uncertain and rapidly changing climate.

American College of Obstetricians and Gynecologists, 2014

The American College of Obstetricians and Gynecologists; “Health Disparities in Rural Women;” Committee Opinion, 2014, 586.

ABSTRACT:

Rural women experience poorer health outcomes and have less access to health care than urban women. Many rural areas have limited numbers of health care providers, especially women’s health providers. Rural America is heterogeneous where problems vary depending on the region and state. Health care professionals should be aware of this issue and advocate for reducing health disparities in rural women. FULL TEXT

Diepietro Mager, 2020

DiPietro Mager, Natalie Ann. (2020). Preconception and Interconception Health and Routine Health Service Use Among Women in a Rural Midwestern County (Doctor of Philosophy), Indiana University.

ABSTRACT:

Advancement of preconception and interconception health is a key element to improve women’s health as well as pregnancy outcomes. Little is known about the preconception and interconception health status of rural Midwestern populations in the United States. The primary objective of this study was to determine the preconception and interconception health status as well as behaviors of reproductive age women living in a rural Midwestern area. Secondary objectives were to quantify process measures of health care access and barriers to care, as well as determine disparities in preconception and interconception health status among women in this rural area as compared to statewide estimates. As existing national or state secondary data sources often have limitations in data derived from areas with low population densities or insufficient sample sizes to generate reliable estimates, a cross-sectional study was performed using a 34item survey. Data were collected from February to May 2019 from 315 non-pregnant women ages 18-45 years in a rural county in northwestern Ohio. Nearly all women surveyed had at least one risk factor associated with poor pregnancy outcomes, many of which were modifiable. Nearly half of all respondents reported at least one barrier to receipt of health care services. Women in this rural county fared worse for several preconception and interconception health measures when compared to statewide estimates derived from Behavioral Risk Factor Surveillance System and Ohio Pregnancy Assessment Survey data. These findings illustrate the need for continued development of interventions to improve preconception and interconception health for rural women as well as improved methods to capture and analyze data on important subpopulations at risk.

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