Agricultural Insecticides Research Articles

Effects of short-term oral combined exposure to environmental immunotoxic chemicals in mice

People are constantly exposed to environmental chemicals through contact with the atmosphere or by ingestion of food. Therefore, when conducting safety assessments, the immunotoxic effects of combinations of chemicals in addition to toxicities produced by each chemical alone should be considered. The objective of the studies reported here were to demonstrate the combined effects of three well-known environmental immunotoxic chemicals -- methoxychlor (MXC), an organochlorine compound; parathion (PARA), an organophosphate compound; and piperonyl butoxide (PBO), an agricultural insecticide synergist -- by using a short-term oral exposure method. Seven-week-old Balb/cAnN mice received daily oral exposure to either one or two of the environmental immunotoxic chemicals for 5 consecutive days. On Day 2, all mice in each group were immunized with sheep red blood cells (SRBC), and their SRBC-specific IgM responses were analyzed by using an enzyme-linked immunosorbent assay and plaque-forming cell assay. T- and B-cell counts in the mouse spleens were also assessed via surface antigen expression. Mice that received MXC + PARA and PBO + MXC treatment showed marked decreases in SRBC-specific IgM production and T- and B-cell counts compared with those in mice that received vehicle control or the corresponding individual test substance. This suggests that simultaneous exposure to multiple environmental chemicals increases the immunotoxic effects of the chemicals compared to individual exposure.

Crocin Improves Lipid Dysregulation in Subacute Diazinon Exposure through ERK1/2 Pathway in Rat Liver

Diazinon Yis one of the most broadly used organophosphorus insecticides in agriculture. It has been shown that exposure to diazinon may interfere with lipid metabolism. Moreover, the hypolipidemic effect of crocin has been established. Earlier studies revealed the major role of Extracellular signal-regulated kinase (ERK) pathways in low-density lipoprotein receptor (LDLr) expression. The aim of this study was to evaluate changes in the regulation of lipid metabolism, ERK and LDLr expression in the liver of rats exposed to subacute diazinon. Furthermore ameliorating effect of crocin on diazinon induced disturbed cholesterol homeostasis was studied. 24 Rats were divided into 4 groups and received following treatments for 4 weeks; Corn oil (control), diazinon (15mg/kg per day, orally) and crocin (12.5 and 25mg/kg per day, intraperitoneally) in combination with diazinon (15 mg/kg). The levels of cholesterol, triglyceride and LDL in blood of rats were analyzed. Moreover mRNA levels of LDLr and ERK1/2 as well as protein levels of total and activated forms of ERK1/2 in rat liver were evaluated by Western blotting and quantitative real time polymerase chain reaction analysis. Our data showed that subacute exposure to diazinon significantly increased concentrations of cholesterol, triglyceride and LDL. Moreover diazinon decreased ERK1/2 protein phosphorylation and LDLr transcript. Crocin reduced inhibition of ERK activation and diazinon-induced hyperlipemia and increased levels of LDLr transcript. Crocin may be considered as a novel protective agent in diazinon-induced hyperlipemia through modulating of ERK pathway and increase of LDLr expression.

Synthesis, Insecticidal Activities, and SAR Studies of Novel Pyridylpyrazole Acid Derivatives Based on Amide Bridge Modification of Anthranilic Diamide Insecticides

Anthranilic diamides are one of the most important classes of modern agricultural insecticides. To discover new structure-modified compounds with high activity, series of novel carbonyl thioureas, carbonyl ureas, oxadiazoles, carbonyl thiophosphorylureas, oxadiazole-containing amides, and thiazoline-containing amides were designed through the modification of the amide bridge based on the structure of chlorantraniliprole and were synthesized, and bioassays were carried out. The compounds were characterized and confirmed by melting point, IR, (1)H NMR, and elemental analyses or HRMS. Preliminary bioassays indicated that some compounds exhibited significant insecticidal activities against oriental armyworm, diamondback moth, beet armyworm, corn borer, and mosquito. Among them, trifluoroethoxyl-containing carbonyl thiourea 20a showed best larvicidal activity against oriental armyworm, with LC50 and LC95 values of 0.1812 and 0.7767 mg/L, respectively. Meanwhile, 20c and 20e showed 86 and 57% death rates against diamondback moth at 0.005 mg/L, and the LC50 values of the two compounds were 0.0017 and 0.0023 mg/L, respectively, which were lower than that of the control chlorantraniliprole. The relationship between structure and insecticidal activity was discussed, and the HF calculation results indicated that the carbonyl thiourea moiety plays an important role in the insecticidal activity. The present work demonstrated that the trifluoroethoxyl-containing carbonyl thioureas can be used as lead compounds for further development of novel insecticides.

Methylamine removal using mixed bacterial strains in a continuous stirred tank reactor (CSTR) system

Methylamine (MA) is an organic compound that can be found in many commercial applications (agricultural chemicals, including herbicides, fungicides, insecticides, biocides, and miticides; catalysts; pharmaceuticals; resin manufacturing). It has a strong odor similar to fish and can cause chemical burns to the eyes and skin. The vapor from this chemical is extremely irritating to the nose, throat, lungs, skin, and eyes. The indiscriminate discharge of improperly treated chemical contaminated wastewater or wastes into a natural water body will cause serious environmental pollution problems and severe adverse impacts to the aquatic ecology. The goal of this investigation is to remove MA using a continuous stirred-tank reactor (CSTR) and to understand the ability of mixed bacteria strains to treat different initial MA concentrations in synthetic and actual industrial wastewaters in the CSTR. The following results were obtained: When the hydraulic retention time (HRT) was 1.136 day, the MA removed efficiency in the CSTR was the best. When the HRT was 1.136 day, the mixed strains could utilize 1000 mg l−1 MA both from synthetic wastewater and actual industrial wastewater for growth in the CSTR. The MA removal efficiency reached 100% in the CSTR.

A review of Dichlorvos toxicity in fish

Among the wide majority of pesticides, dichlorvos (2, 2-dichlorovinyl dimethyl phosphate), a organophosphate compound, is commonly used as agricultural insecticide. It is extremely toxic to non target organisms like fish and hampers fish health through impairment of metabolism, sometimes leading to death. As one of the few organophosphates still registered for use, dichlorvos has elicited worldwide concern for many reasons. This study is a review of potential adverse effects of dichlorvos in fish.

Be(e)coming experts: The controversy over insecticides in the honey bee colony collapse disorder

In this article, we explore the politics of expertise in an ongoing controversy in the United States over the role of certain insecticides in colony collapse disorder – a phenomenon involving mass die-offs of honey bees. Numerous long-time commercial beekeepers contend that newer systemic agricultural insecticides are a crucial part of the cocktail of factors responsible for colony collapse disorder. Many scientists actively researching colony collapse disorder reject the beekeepers’ claims, citing the lack of conclusive evidence from field experiments by academic and industry toxicologists. US Environmental Protection Agency regulators, in turn, privilege the latters’ approach to the issue, and use the lack of conclusive evidence of systemic insecticides’ role in colony collapse disorder to justify permitting these chemicals to remain on the market. Drawing on semistructured interviews with key players in the controversy, as well as published documents and ethnographic data, we show how a set of research norms and practices from agricultural entomology came to dominate the investigation of the links between pesticides and honey bee health, and how the epistemological dominance of these norms and practices served to marginalize the knowledge claims and policy positions of commercial beekeepers in the colony collapse disorder controversy. We conclude with a discussion of how the colony collapse disorder case can help us think about the nature and politics of expertise.

Insecticide Susceptibility of Field-Collected Populations ofCulex tritaeniorhynchusin the Republic of Korea

The toxicities of 10 insecticides were examined against late third instar Culex tritaeniorhynchus Giles (Diptera: Culicidae) using the direct-contact mortality bioassay. Six geospatially-distant field mosquitoes were collected from Chuncheon-si, Hwaseong, Seosan. Jeonju, Daegu, and Busan in the Republic of Korea. Marked regional variations of insecticide susceptibility were observed. Field populations of Seosan, Jeonju, and Daegu from agricultural areas showed higher to extremely higher insecticide susceptibility to pyrethroids than those of Chuncheon-si, Hwaseong, and Busan strains from non-agricultural areas. Extremely high to low levels of susceptibility were measured: bifenthrin, susceptible ratio (SR) = 2.7–896.3; β-cyfluthrin, SR = 1.8–633.3; α-cypermethrin, SR = 1.2–1,051.9; deltamethrin, SR = 1.3–711.1; permethrin, SR = 1.5–1,053.4; etofenprox, SR = 2.2–29.3; chlorfenapyr, SR = 5.1–103.6; chlorpyrifos, SR = 2.3– 337.0; fenitrothion, SR = 2.0–142.3; and fenthion, SR = 1.4–186.2. Cx. tritaeniorhynchus populations from rice paddies had been under heavy selection pressure due to the agricultural insecticides, and that's why the mosquito species demonstrated high resistance to pyrethroids, which were used for a long time to control agricultural pests in the localities. These results indicate that careful selection and rotational use of these insecticides may result in continued satisfactory control against field populations of Japanese encephalitis vector mosquitoes.

Probabilistic risk assessment of insecticide concentrations in agricultural surface waters: a critical appraisal

Due to the specific modes of action and application patterns of agricultural insecticides, the insecticide exposure of agricultural surface waters is characterized by infrequent and short-term insecticide concentration peaks of high ecotoxicological relevance with implications for both monitoring and risk assessment. Here, we apply several fixed-interval strategies and an event-based sampling strategy to two generalized and two realistic insecticide exposure patterns for typical agricultural streams derived from FOCUS exposure modeling using Monte Carlo simulations. Sampling based on regular intervals was found to be inadequate for the detection of transient insecticide concentrations, whereas event-triggered sampling successfully detected all exposure incidences at substantially lower analytical costs. Our study proves that probabilistic risk assessment (PRA) concepts in their present forms are not appropriate for a thorough evaluation of insecticide exposure. Despite claims that the PRA approach uses all available data to assess exposure and enhances risk assessment realism, we demonstrate that this concept is severely biased by the amount of insecticide concentrations below detection limits and therefore by the sampling designs. Moreover, actual insecticide exposure is of almost no relevance for PRA threshold level exceedance frequencies and consequential risk assessment outcomes. Therefore, we propose a concept that features a field-relevant ecological risk analysis of agricultural insecticide surface water exposure. Our study quantifies for the first time the environmental and economic consequences of inappropriate monitoring and risk assessment concepts used for the evaluation of short-term peak surface water pollutants such as insecticides.

Pre-natal/juvenile chlorpyrifos exposure associated with immunotoxicity in adulthood in Swiss albino mice

Chlorpyrifos (CPF) is a widely used agricultural organophosphorus insecticide (OP). Epidemiological studies have reported that children living in an OP contaminated environment, showed altered immune function. However, there is a paucity of experimental evidence for CPF-induced toxicity in the developmental phases of immune system. The current studies sought to ascertain the effect of CPF on the developing immune system of mice. Swiss albino dams were exposed orally with 0, 0.3, and 3.0 mg CPF/kg/day from GD12 to PND7, and then pups were directly dosed with CPF (by gavage) through PND42. One week after the final dose of CPF (i.e. on PND49), immunotoxicities in these offspring were assessed. These analyses revealed that there were increases in Foxp3+CD25+CD4+ T-regulatory (Treg) cell frequency in the spleens of 3.0 mg CPF/kg/day-exposed female mice, but not in males. In contrast, the anti-sheep red blood cells IgM response was reduced in both genders. Moreover, splenic lymphoproliferative response to phytohemagglutinin (PHA), concanavalin A (ConA), and lipopolysaccharide (LPS), as well as interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and interleukin (IL)-6 production following LPS stimulation decreased in mice of both sexes at higher CPF doses. Together, these findings suggest that developmental CPF exposure might cause immunosuppression in mice. Some of these outcomes might arise, in part, through a suppression of pro-inflammatory cytokine production and/or changes in the responsivity (specifically to mitogens) of lymphocytes in these hosts.

Do residues of imidacloprid in surface water cause honeybee colony losses?

Honeybee colony mortality is a problem at a world wide scale. Insecticides in agriculture and horticulture might contribute, especially the neonicotinoid imidacloprid, which is a commonly used systemic insecticide that might induce several effects at sublethal concentrations. Furthermore it is very persistent in soil and water. At several locations in the Netherlands imidacloprid was found in the surface water in relatively high concentrations. The exceeding of the acceptable levels was suggested to be causally related to honeybee colony losses, and several groups in society are concerned. The aim of this study is to determine whether concentrations of imidacloprid in surface water influence honeybee mortality in the Netherlands. Therefore monitoring data of honeybee mortality from 2005, 2006, 2007 and 2009 and several covariates are used. Data of honeybee mortality are linked to maximum values of imidacloprid concentrations in surface water. For a realistic risk valuation, three foraging distances are used, i.e. 1000 meters, 3000 meters and 7500 meters. Peak concentrations of imidacloprid within a radius of 7500 meters around the colonies appeared negatively correlated with honeybee mortality. However, imidacloprid was aliased with the factor beekeeper, so the earlier shown correlation is possibly a disguised beekeepers effect. A negative effect of imidacloprid in surface water on honeybee colony survival in the Netherlands is therefore not shown in this study. Although it can not be proven that imidacloprid has no influence on honeybee mortality, it seems unlikely that imidacloprid in surface water as a single factor is relevant to the current problem. Possible interactions between imidacloprid and factors that undermine the vitality of colonies are not taken into account in this study.

Determination of elemental sulfur in phosphorous pentasulfide by temperature modulated differential scanning calorimetry

Abstract Phosphorous pentasulfide is an important starting material for a number of commercial chemicals. Examples include lubricant additives (Spikes, Trib Lett 17:469–489, 2004), agricultural insecticides (Kirk-Othmer, Enycl Chem Technol 14:549–552, 1995), and mining ore flotation agents. Phosphorous pentasulfide is a mixture of several components, one of which is free elemental sulfur, present at levels of approximately 50 ppm to 20,000 ppm (2 %). The amount of free sulfur present in the phosphorous pentasulfide can impact manufacturing, such as zinc dithiosulfate processing. Therefore, an accurate and fast analytical method to measure elemental sulfur in phosphorous pentasulfide would be of value compared to what is available now.

Malathion exposure and insulin resistance among a group of farmers in Al-Sharkia governorate

ObjectivesExposure to certain environmental toxins may be associated with increased risk of developing diabetes mellitus. The aim of the present study was to investigate the relation between chronic exposure to malathion and insulin resistance among farmers. Design and methodsThe study included 98 non diabetic farmers who handle agricultural insecticides during their field work. The range of the exposure period for agricultural pesticides was 15–20years. All farmers were males with mean age 39±12years. Another 90 administrative employees at Zagazig University Hospitals, non diabetic males age matched were selected as controls. History taking including family history for diabetes, assessment of blood pressure, height, weight, waist circumference and body mass index was done for all participants. Blood samples were withdrawn for measurement of malathion concentration, fasting blood glucose level and fasting insulin level for calculation of homeostasis model assessment of insulin resistance (HOMA-IR). Results24.5% had positive family history for diabetes. It was observed that there was a significant increase in the mean values of malathion blood concentration among studied farmers compared to corresponding controls. There was a positive correlation between malathion blood concentration, waist circumference and insulin resistance. It was also observed that the increase in the mean values of waist circumference and body mass index was accompanied by a significant increase in the mean values of malathion blood concentration. ConclusionThe current results suggested that chronic exposure of non diabetic farmers to organophosphorus malathion pesticides may induce insulin resistance. This effect tended to strengthen as waist circumference increases.

Somatic Cell Nuclear Transfer Cloning: Practical Applications and Current Legislation

Somatic cloning is emerging as a new biotechnology by which the opportunities arising from the advances in molecular genetics and genome analysis can be implemented in animal breeding. Significant improvements have been made in SCNT protocols in the past years which now allow to embarking on practical applications. The main areas of application of SCNT are: Reproductive cloning, therapeutic cloning and basic research. A great application potential of SCNT based cloning is the production of genetically modified (transgenic) animals. Somatic cell nuclear transfer based transgenic animal production has significant advances over the previously employed microinjection of foreign DNA into pronuclei of zygotes. This cell based transgenesis is compatible with gene targeting and allows both, the addition of a specific gene and the deletion of an endogenous gene. Efficient transgenic animal production provides numerous opportunities for agriculture and biomedicine. Regulatory agencies around the world have agreed that food derived from cloned animals and their offspring is safe and there is no scientific basis for questioning this. Commercial application of somatic cloning within the EU is via the Novel Food regulation EC No. 258/97. Somatic cloning raises novel questions regarding the ethical and moral status of animals and their welfare which has prompted a controversial discussion in Europe which has not yet been resolved.

Immunotoxicity in mice induced by short-term exposure to methoxychlor, parathion, or piperonyl butoxide

Exposure to environmental agents can compromise numerous immunological functions. Immunotoxicology focuses on the evaluation of the potential adverse effects of xenobiotics on immune mechanisms that can lead to harmful changes in host responses such as: increased susceptibility to infectious diseases and tumorigenesis; the induction of hypersensitivity reactions; or an increased incidence of autoimmune disease. In order to assess the immunosuppressive response to short-term exposure to some commonly used pesticides, the studies here focused on the response of mice after exposures to the organochlorine pesticide methoxychlor, the organophosphorus pesticide parathion, or the agricultural insecticide synergist piperonyl butoxide. In these studies, 7-week-old mice were orally administered (by gavage) methoxychlor, parathion, or piperonyl butoxide daily for five consecutive days. On Day 2, all mice in each group were immunized with sheep red blood cells (SRBC), and their SRBC-specific IgM responses were subsequently assessed. In addition, levels of B-cells in the spleen of each mouse were also analyzed via surface antigen expression. The results of these studies indicated that treatments with these various pesticides induced marked decreases in the production of SRBC-specific IgM antibodies as well as in the expression of surface antigens in IgM- and germinal center-positive B-cells. Based on these outcomes, it is concluded that the short-term exposure protocol was able to detect potential immunosuppressive responses to methoxychlor, parathion, and piperonyl butoxide in situ, and, as a result, may be useful for detecting other environmental chemical-related immunotoxicities.

Regulatory FOCUS Surface Water Models Fail to Predict Insecticide Concentrations in the Field

The FOrum for the Co-ordination of pesticide fate models and their USe (FOCUS) exposure models are used to predict the frequency and magnitude of pesticide surface water concentrations within the European regulatory risk assessment. The predictions are based on realistic worst-case assumptions that result in predicted environmental concentrations (PEC). Here, we compared for the first time a larger data set of 122 measured field concentrations (MFC) of agricultural insecticides extracted from 22 field studies to respective PECs by using FOCUS steps 1-4. While FOCUS step 1 and 2 PECs generally overpredicted the MFCs, 23% of step 3 and 31% of step 4 standard PECs were exceeded by surface water MFCs, which questions the protectiveness of the FOCUS exposure assessment. Using realistic input parameters, step 3 simulations underpredicted MFCs in surface water and sediment by 43% and 78%, respectively, which indicate that a higher degree of realism even reduces the protectiveness of model results. The ratios between PEC and MFC in surface water were significantly lower for pyrethroids than for organophosphorus or organochlorine insecticides, which suggests that the FOCUS predictions are less protective for hydrophobic insecticides. In conclusion, the FOCUS modeling approach is not protective for insecticide concentrations in the field.

Single Versus Combined Lethal Effects of Three Agricultural Insecticides on Larvae of the Freshwater Insect Chironomus dilutus

Pesticides are currently regulated individually but are present in aquatic systems as mixtures of toxicants. In this study, the lethal effects of three agricultural insecticides--chlorpyrifos, imidacloprid and dimethoate--on Chironomus dilutus larvae were examined. Ninety-six-hour static bioassays were performed using single, binary, and ternary toxicant mixtures. The effects of the binary mixtures were investigated using the MIXTOX model to determine if the mixtures behaved additively, synergistically, or antagonistically. Dimethoate was much less toxic than chlorpyrifos or imidacloprid. Chlorpyrifos and dimethoate were not additive in mixture despite their common mode of action (MOA) and resulted in opposing effects (synergism and antagonism, respectively) when combined with imidacloprid. Synergism was observed in the ternary mixture. These results suggest that current mixture models based on MOA alone may not always be adequate in describing mixture effects, as in the current situation of mixtures with relatively few components. Other factors, such as water solubility, secondary MOA, and mechanisms of toxicity, should also be considered in future investigations of multichemical-mixture effects.

Chlorpyrifos biodegradation and 3,5,6-trichloro-2-pyridinol production by actinobacteria isolated from soil

Chlorpyrifos (CP) is a widely used agricultural insecticide that is hazardous to both the environment and human health. Therefore, it is an essential to develop approaches to remove this compound from contaminated soils, water and sediments. In this study, actinobacteria were isolated from an agricultural soil that had received continuous applications of CP. Four strains were selected as a result of their tolerance to 50 mg L−1 of CP in agar plate and they were identified as Streptomyces sp. based on 16S rDNA. According to relationship of CP degradation and microbial growth studies, two isolates were selected and were named Streptomyces sp. strain AC5 and Streptomyces sp. strain AC7. The strains were cultivated in liquid medium with CP at concentrations of 25 mg L−1 and 50 mg L−1 for 72 h. The results indicated that both strains were able to rapidly degrade CP with about 90% degradation after 24 h of incubation. A different pattern of CP degradation was observed when its main metabolite, 3,5,6-trichloro-2-pyridinol (TCP) was monitored. A maximum concentration of 0.46 mg L−1 of TCP was produced by Streptomyces sp. strain AC5 and its concentration decreased as a function of time. In contrast, TCP production by Streptomyces sp. AC7 increased over time from 1.31 mg L−1 to 4.32 mg L−1. CP degradation was associated to microbial growth of the strains, pH modification, glucose consumption and organic acids excretion in the liquid medium. This work constitutes one of the few reports of Streptomyces as CP-degraders. Given the high CP degradation observed here, the Streptomycetes strains show a good potential as CP-degrading actinobacteria.

Strategies for the synthesis and molecular modeling aiming to discover biorational agricultural insecticides

This work presents two proposals for the synthesis of halogenated aryl thiosulfonates which are of biologically interesting compounds. Inhibitors of proteases and juvenile hormone mimetizing are already successfully employed for managing pest-insects However, many of these products can be always improved in the aspects of specificity implying in low cost to the farmer. The major objective of this work is the synthesis of thiosulfonates analogues of commercial products which are inhibitors of serine-protease and juvenile hormone mimetizing compounds that can be applied as leads for production of insecticides that can contribute to the control of pest-insects in economically important plantation and stored grains. The scientific research group SINTMOLB (CNPq) is involved with studies related to the synthesis of phenolic compounds with insecticidal potential. Some important results have already been obtained and, in this new project, it is being explored the synthesis of new compounds, computational analysis, and biological tests to evaluate protease inhibitory effect.

Degradation of methyl parathion using hydrodynamic cavitation: Effect of operating parameters and intensification using additives

Methyl parathion (C8H10NO5PS), which is an organophosphorus pesticide that has been widely used as an agricultural insecticide in India, can result in significant water pollution due to its biorefractory nature and longer stability. In the present work, degradation of methyl parathion has been investigated using hydrodynamic cavitation reactors with possible intensification studies using different approaches. Effect of different parameters like operating pressures (1–8bar), operating temperatures (sets of intense cooling, moderate cooling and uncontrolled operation) and initial pH (2.2–8.2) has been investigated initially. Under the optimized set of operating parameters, the effect of process intensifying parameters like hydrogen peroxide (25–200mg/l), carbon tetrachloride (1–6g/l) and Fenton’s reagent (H2O2:FeSO4 ranging from 1:1 to 1:6) on the extent of degradation has been investigated. Effect of radical scavengers like sodium bicarbonate and tert-butanol on the extent of degradation was also investigated with an objective of establishing the controlling mechanism. More than 90% degradation of methyl parathion was achieved using combination of hydrodynamic cavitation with H2O2 and Fenton’s reagent. TOC analysis at optimum conditions was also performed to quantify the extent of mineralization and it has been observed that a maximum of 76% TOC reduction is obtained. The study has also focused on the determination of intermediate products formed during the degradation. It has been established that hydrodynamic cavitation in the presence of additives can be effectively used for complete removal of methyl parathion.

Dying Bees and the Social Production of Ignorance

This article utilizes the ongoing debates over the role of certain agricultural insecticides in causing Colony Collapse Disorder (CCD)—the phenomenon of accelerated bee die-offs in the United States and elsewhere—as an opportunity to contribute to the emerging literature on the social production of ignorance. In our effort to understand the social contexts that shape knowledge/nonknowledge production in this case, we develop the concept of epistemic form. Epistemic form is the suite of concepts, methods, measures, and interpretations that shapes the ways in which actors produce knowledge and ignorance in their professional/intellectual fields of practice. In the CCD controversy, we examine how the (historically influenced) privileging of certain epistemic forms intersects with the social dynamics of academic, regulatory, and corporate organizations to lead to the institutionalization of three interrelated and overlapping types of ignorance. We consider the effects of these types of ignorance on US regulatory policy and on the lives of different stakeholders.