Pounds Of Active Ingredient Research Articles

Maternal residential exposure to agricultural pesticides and birth defects in a 2003 to 2005 North Carolina birth cohort.

Birth defects are responsible for a large proportion of disability and infant mortality. Exposure to a variety of pesticides have been linked to increased risk of birth defects. We conducted a case-control study to estimate the associations between a residence-based metric of agricultural pesticide exposure and birth defects. We linked singleton live birth records for 2003 to 2005 from the North Carolina (NC) State Center for Health Statistics to data from the NC Birth Defects Monitoring Program. Included women had residence at delivery inside NC and infants with gestational ages from 20 to 44 weeks (n = 304,906). Pesticide exposure was assigned using a previously constructed metric, estimating total chemical exposure (pounds of active ingredient) based on crops within 500 meters of maternal residence, specific dates of pregnancy, and chemical application dates based on the planting/harvesting dates of each crop. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals for four categories of exposure (<10(th) , 10-50(th) , 50-90(th) , and >90(th) percentiles) compared with unexposed. Models were adjusted for maternal race, age at delivery, education, marital status, and smoking status. We observed elevated ORs for congenital heart defects and certain structural defects affecting the gastrointestinal, genitourinary and musculoskeletal systems (e.g., OR [95% confidence interval] [highest exposure vs. unexposed] for tracheal esophageal fistula/esophageal atresia = 1.98 [0.69, 5.66], and OR for atrial septal defects: 1.70 [1.34, 2.14]). Our results provide some evidence of associations between residential exposure to agricultural pesticides and several birth defects phenotypes. Birth Defects Research (Part A) 106:240-249, 2016. © 2016 Wiley Periodicals, Inc.

Residential Proximity to Agricultural Pesticides and Risk of Non-Cardiac Birth Defects

Birth defects are responsible for a large proportion of disability and infant mortality. Pesticides have been linked sporadically to increased risk of birth defects. We conducted a case-control study to estimate the associations between a residence-based metric of agricultural pesticide exposure and non-cardiac birth defects. We linked live singleton birth records for 2003-2005 from the North Carolina (NC) State Center for Health Statistics to data from the NC Birth Defects Monitoring Program. Included women had residence at delivery inside NC and infants with gestational ages from 20-44 weeks (n=304,906). Pesticide exposure was assigned using a previously constructed metric estimating total chemical exposure (pounds of active ingredient) based on crops within 500 meters of residence, specific dates of pregnancy, and chemical application dates based on the planting/harvesting dates of each crop. Logistic regression was used to estimate odds ratios (OR (95% confidence interval)) for three categories of exposure(&lt;50, 50-90, &gt;90 percentiles) compared to unexposed. Models were adjusted for maternal race, age at delivery, education, marital status, and smoking status. We observed positive ORs for specific birth defects, including tracheal esophageal fistula (OR highest exposure v unexposed = 2.05 (0.78, 5.41)), hypertrophic pyloric stenosis (OR = 1.70(1.27, 2.28)), upper limb deficiency (OR = 1.75 (0.84, 3.62)), obstructive genitourinary defect (OR = 1.12 (0.84, 1.49)) and hypospadias (OR = 1.18 (0.92, 1.52)). We observed some negative associations (e.g., anotia/microtia OR = 0.82 (0.33, 2.07)). The three Trisomy anomalies (13, 18, 21), examined as negative controls, showed null effects. Our results suggest an association between residential exposure to agricultural pesticides and specific birth defects phenotypes. The views expressed in this abstract are those of the authors and do not necessarily reflect the views or policies of the U.S. Environmental Protection Agency.

Neurodevelopmental disorders and prenatal residential proximity to agricultural pesticides: the CHARGE study.

Background: Gestational exposure to several common agricultural pesticides can induce developmental neurotoxicity in humans, and has been associated with developmental delay and autism.Objectives: We evaluated whether residential proximity to agricultural pesticides during pregnancy is associated with autism spectrum disorders (ASD) or developmental delay (DD) in the Childhood Autism Risks from Genetics and Environment (CHARGE) study.Methods: The CHARGE study is a population-based case–control study of ASD, DD, and typical development. For 970 participants, commercial pesticide application data from the California Pesticide Use Report (1997–2008) were linked to the addresses during pregnancy. Pounds of active ingredient applied for organophophates, organochlorines, pyrethroids, and carbamates were aggregated within 1.25-km, 1.5-km, and 1.75-km buffer distances from the home. Multinomial logistic regression was used to estimate the odds ratio (OR) of exposure comparing confirmed cases of ASD (n = 486) or DD (n = 168) with typically developing referents (n = 316).Results: Approximately one-third of CHARGE study mothers lived, during pregnancy, within 1.5 km (just under 1 mile) of an agricultural pesticide application. Proximity to organophosphates at some point during gestation was associated with a 60% increased risk for ASD, higher for third-trimester exposures (OR = 2.0; 95% CI: 1.1, 3.6), and second-trimester chlorpyrifos applications (OR = 3.3; 95% CI: 1.5, 7.4). Children of mothers residing near pyrethroid insecticide applications just before conception or during third trimester were at greater risk for both ASD and DD, with ORs ranging from 1.7 to 2.3. Risk for DD was increased in those near carbamate applications, but no specific vulnerable period was identified.Conclusions: This study of ASD strengthens the evidence linking neurodevelopmental disorders with gestational pesticide exposures, particularly organophosphates, and provides novel results of ASD and DD associations with, respectively, pyrethroids and carbamates.Citation: Shelton JF, Geraghty EM, Tancredi DJ, Delwiche LD, Schmidt RJ, Ritz B, Hansen RL, Hertz-Picciotto I. 2014. Neurodevelopmental disorders and prenatal residential proximity to agricultural pesticides: the CHARGE study. Environ Health Perspect 122:1103–1109; http://dx.doi.org/10.1289/ehp.1307044

The Effects of Atrazine on the Production of Steroids in Rat Granulosa Cells.

Atrazine is one of the most widely used herbicides in the United States. Introduced in the 1950s, atrazine is a broad spectrum herbicide with current total annual use of approximately 76 million pounds of active ingredient. Frogs exhibit gonadal malformations and/or variations in normal hormone production following exposure to atrazine. Based on in vitro studies using H295R cells, it has been speculated that these effects are the result of the influence of atrazine on aromatase (enzyme responsible for the conversion of androgens into estrogens) expression and/or activity; however, this hypothesis remains controversial. In order to determine if/how atrazine is affecting aromatase activity and reproductive function, the specific molecular mechanisms which are targeted by atrazine need to be determined. The orphan nuclear receptor steroidogenic factor 1 (SF-1) regulates the transcription of a large number of genes involved in steroidogenesis and reproduction. SF-1 binds its response element and regulates transcription constitutively; however, ligand binding may enhance SF-1 activity. It has been shown that atrazine increases SF-1 expression, and binds to SF-1. Since SF-1 is located in the rat aromatase promoter, and has been localized to rat granulosa and theca cells, atrazine may induce binding and activation of the aromatase promoter, leading to an increase in aromatase activity. The current studies were conducted to determine if aromatase expression and activity could be measured in rat granulosa cells in culture and to determine the effects of atrazine on these measures. Twenty-seven day old Wistar rats were injected with 20 IU of PMSG to stimulate follicular development. After 48 hours the rats were killed and ovaries collected. Granulosa cells were isolated and placed in culture with vehicle alone (0.3 % ethanol), atrazine (1, 10 or 30 µM), testosterone (0.017 µM), or 4-hydroxyandrostenedione (10 µM). Following 24 hours in culture some of the media and granulosa cells were collected for radio-immunoassays (RIAs) and real time PCR, respectively, and other cells remained in culture to measure aromatase activity using the tritiated water assay. Atrazine at all three concentrations did not affect estradiol production; however, atrazine at 10 and 30 µM significantly increased progesterone concentrations as compared to controls (p ≤ 0.05). Aromatase (CYP19) and SF-1 expression of mRNA were not significantly affected by any of the atrazine treatments. In summary, our results show that it is possible to detect aromatase activity from granulosa cells in culture: however, it has yet to be determined if atrazine affects aromatase activity in granulosa cell cultures. These results suggest that atrazine does not affect follicular estrogen production, but that it may affect luteinization or luteal hormone production. This abstract does not necessarily reflect EPA policy.

Developing a pesticide risk assessment tool to monitor progress in reducing reliance on high-risk pesticides

A methodology is presented for the development of a pesticide risk assessment tool that was used to monitor progress in reducing use of high-risk pesticides in Wisconsin potato production. Multi-attribute toxicity factors are calculated that reflect each pesticide’s acute and chronic toxicity to mammals, birds, fish and small aquatic organisms, and compatibility with biointensive Integrated Pest Management. These factors are then multiplied by the pounds of active ingredient of a given pesticide applied to estimate pesticide-specific toxicity units. Wisconsin potato industry baseline toxicity units by type of pesticide and for 11 targeted higher-risk pesticides are presented for 1995. Reductions in toxicity units from this baseline are reported for 1997 and 1999, as are reductions achieved in a commercial-scale field experiment in 2000.

Correlation analysis of pesticide use data and cancer incidence rates in California counties.

California, the leading agricultural state in the United States, has maintained a population-based cancer registry since 1988, and it also maintains a comprehensive, state-wide pesticide reporting system. Data on cancer incidence and pesticide use reporting are available, by county, for all 58 counties in California. Average annual age-adjusted cancer incidence rates (1988-1992), on a county-, sex-, and race/ethnicity-specific basis, were obtained from the California Cancer Registry (CCR), which maintains the population-based cancer registry throughout California. Pesticide use data (i.e., pounds of active ingredient applied annually in each county) were obtained from the California Department of Pesticide Regulation for 1993. Investigators used Pearson product-moment correlation coefficients (r) to correlate age-adjusted incidence rates for selected cancers with the use data for selected pesticides. For most sex- and race/ethnicity-specific groups, the correlation coefficients were very close to zero or negative in sign, indicating no correlation between pesticide use and cancer incidence. There were, however, several exceptions, particularly in Hispanic males for whom the following correlations were observed: leukemia and atrazine (r=.40), leukemia and 2,4-dichlorophenoxyacetic acid (r=.41), leukemia and captan (r=.46), atrazine and brain cancer (r=.54), and atrazine and testicular cancer (r=.41). For black males, we observed the following: atrazine and prostate cancer (r=.67) and Captan and prostate cancer (r=.49). In females, only a few of the correlations were elevated. Although most of the correlations examined in this analysis were not elevated, several of those in the Hispanic and black male populations were. These segments of the population have traditionally been employed as farm workers in California and have had the greatest potential for exposure to pesticides. This was an ecological study for which no data about exposure to pesticides at the individual level were available for analysis. In addition, no latency period was allowed between potential exposure and diagnosis with cancer. However, the results obtained in two minority groups who represented the majority of farm workers in the fields suggested that additional research studies, in which more rigorous study designs are used, should be conducted in those groups.

Determination of atrazine residues in water and soil by enzyme immunoassay.

Atrazine, a triazine herbicide, is the second most widely used pesticlde in the United States with approximately 79 million pounds of active ingredient being applled each year (Anonymous 1987) as a preor post-emergent weed-control agent in the U.S. for corn, sorghum, sugarcane and pineapple. Because of its extensive use, possible seasonal stability and inadequate toxicological data (Wilson et al. 1987), there is a need for monitoring atrazine in water and soil. Municipal and private water sources should be monitored periodlcally in areas of frequent atrazine use. In soil, atrazine carry over may be injurious to certain rotational crops and thus the soil should be analyzed before planting (Ferris and Haigh 1987).

Adsorption of carbofuran and movement on soil thin layers.

Carbofuran is a widely used soil insecticide throughout the Midwest as a prophylactic treatment against corn rootworms. In Iowa and Illinois alone, approximately 3.5 million pounds of active ingredient were applied to the soil in 1979. 1 Since treated fields occur in both watershed and nonwatershed areas alike, it is desirable to describe the translocation potential of this insecticide. HELLING (1968) devised a mobility classification for agricultural chemicals based upon their movement on soil thin layers. Since carbofuran mobility has not been assessed by soil TLC, the objective of this study was to determine its movement using this method. Adsorption of carbofuran was also measured to elucidate the relationship between sorption and translocation.

Effect of Di-syston on control of verticillium wilt of Kennebec potatoes

Di-Syston granules applied at 3 and 6 pounds of active ingredient an acre to plots planted withVerticillium-inoculated seed did not result in an increase in yield of potatoes or in the control ofVerticillium wilt over those plots receiving no chemical treatment.

Tests with Systemic Insecticides on Rice

Greenhouse and small plot tests were conducted in 1958 through 1960 with systemic insecticides to control a leafhopper, Draeculacephala Portola Ball, on rice. III two greenouse tests, seed treatment with Di-syston® ( O,O -diethyl S-2(ethylthio)ethyl phosphoroditioate), and phorate at 1 pound active ingredient per 100 pounds of seed, leafhopper control was obtained for approximately 30 days. The most effective control with granulated Di-syston in a greenhouse test was obtained when applied to the soil, flushed with water and flooded 24 hours later. Phorate was slightly more effective than Di-syston when applied to the soil as granules lit the 51-pound rate. At the 4-pound rate, the two were equally effective. In small plot tests, phorate and Di-syston when applied as granules broadcast at 2 pounds of active ingredient per acre, r duced leafhopper populations and increased yields. Phorate and Di-syston at 2 and 4 pounds active per acre applied as glanules in the furrow at planting time produced increases in yield that were significant.

The Effect of Phorate Applied to Seed on the Growth, Development and Insects Attacking Grain Sorghum1

Seed of sorghum variety RS610 was treated with phorate (Thimet 44-D) at the rate of 0.5, 1.0, 2.0 and 4.0 pounds of active ingredient per 100 pounds of seed, with and without Arasan 75 at 10-2/3 ounces. Additional treatments included Arasan 75 and Sticker 25-1 alone and in combination. In field tests the 2- and 4-pound rates seriously reduced stand and delayed plant development as measured by pollen shedding. Plants from seed treated with the 0.5- and I-pound rates shed pollen earlier than the untreated. Highly significant differences in seed yield were associated with differences in stand. The plots receiving the phorate treatments had significantly less yield than the untreated. In greenhouse tests, germination was reduced by the higher dosages and prolonged about 3 days. Treated seed, after 10 months storage, showed a great reduction in germination. Per cent germination under greenhouse conditions was highly significantly correlated with the field stand. Arasan reduced the toxic effect of the phorate. The sticker showed some deleterious effect on germination, which was reduced when combined with Arasan. The higher dosage rates controlled the corn leaf aphid, Rhopalosiphum maidis (Fitch), during the earlier period of growth. However, the phorate treatments gave no control of aphid populations on bagged heads of sorghum in the field.

Thimet as a Low-Temperature Fumigant against the Pea Aphid

On February 25, 1957, two plots of alfalfa at the Walla Walla, Wash., laboratory, each about 0.2 acre, were treated with granulated 2% Thimet3 (0,0-diethyl S-(ethylthio) methyl posphorothioate) at rates of 1 and 2 pounds of active ingredient per acre for control of the pea aphid, Macrosiphum pisi (Harris). The granules were broadcast on the soil surface and not worked in. The odor of Thimet was perceptible for at least 10 days after broadcasting. On March 15 four 50-tip samples were taken from each treated plot and eight similar samples from adjacent untreated alfalfa. When examined in the laboratory, the untreated samples averaged 0.40 pea aphid per tip, samples from the 1-pound dosage 0.03, and those from the 2-pound dosage no aphids. At that time it was supposed that the action of the Thimet was systemic, and no further tests were made except to determine a month later that the alfalfa was not toxic to pea aphids. It was suggested, however, that fumigation might be involved, rather than systemic action, because the mortality occurred so soon after treatment, and the dosages used were too low for systemic action. Therefore, on February 21, 1958, twelve 20-×20-foot plots were treated with ½ or 1 pound per acre of 2% Thimet granules. These plots were laid out in randomized blocks, replicated four times. They were made small so that the Thimet vapor might possibly drift from treated to untreated plots. Counts made just before treatment showed a rather evenly distributed population of pea aphids, averaging 0.77 per tip. One week after treatment one 20-tip sample from each plot was examined for aphids. Out of the 12 samples, 1 contained 20 aphids, 2 had 1 aphid each, and the other 9 had no aphids. All samples containing aphids came from untreated plots. The sample containing 20 aphids was from an untreated plot that was up-wind from all the others, and thus escaped fumigation. The aphid mortality on the other untreated plots indicated considerable drift of the Thimet vapor. When these samples were taken, 5 more tips were taken from each plot, stripped down to a single leaf and the terminal bud, caged and infested with 5 aphids each, of various stages. After 48 hours at 77° F. the cages were examined and the aphid mortality and reproduction recorded. Much growth and reproduction had taken place in all samples, and there was no significant difference between the treated and untreated plots. These results would indicate that no detectable absorption or translocacation of Thimet had occurred at the time the field mortality was found. The field mortality must have been entirely from fumigation.

The Utility of Field Tests for Evaluating Insecticides Against the Garden Symphylid1

From 1955 to 1957 a total of 54 acres were established in field plots to evaluate compounds for the control of Scutigerella immaculata Newport. Productive results were obtained in approximately 10% of the plots. Interpretation of results was complicated in the remainder of the plots by the irregular distribution pattern, non-feeding phases, and preferential feeding habits of the pest. Although it failed to give control in some trials, parathion used as a soil treatment at the rate of 5 pounds of active ingredient per acre consistently gave better results than any other insecticides tested.