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Curl et al., 2019

Curl, C. L., Porter, J., Penwell, I., Phinney, R., Ospina, M., & Calafat, A. M.; “Effect of a 24-week randomized trial of an organic produce intervention on pyrethroid and organophosphate pesticide exposure among pregnant women;” Environment International, 2019, 104957; DOI: 10.1016/j.envint.2019.104957.

ABSTRACT:

BACKGROUND: Introduction of an organic diet can significantly reduce exposure to some classes of pesticides in children and adults, but no long-term trials have been conducted.

OBJECTIVES: To assess the effect of a long-term (24-week) organic produce intervention on pesticide exposure among pregnant women.

METHODS: We recruited 20 women from the Idaho Women, Infants, and Children (WIC) program during their first trimester of pregnancy. Eligible women were nonsmokers aged 18-35 years who reported eating exclusively conventionally grown food. We randomly assigned participants to receive weekly deliveries of either organic or conventional fruits and vegetables throughout their second or third trimesters and collected weekly spot urine samples. Urine samples, which were pooled to represent monthly exposures, were analyzed for biomarkers of organophosphate (OP) and pyrethroid insecticides.

RESULTS: Food diary data demonstrated that 66% of all servings of fruits and vegetables consumed by participants in the “organic produce” group were organic, compared to <3% in the “conventional produce” group. We collected an average of 23 spot samples per participant (461 samples total), which were combined to yield 116 monthly composites. 3-Phenoxybenzoic acid (3-PBA, a non-specific biomarker of several pyrethroids) was detected in 75% of the composite samples, and 3-PBA concentrations were significantly higher in samples collected from women in the conventional produce group compared to the organic produce group (0.95 vs 0.27mug/L, p=0.03). Another pyrethroid biomarker, trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid, was detected more frequently in women in the conventional compared to the organic produce groups (16% vs 4%, p=0.05). In contrast, we observed no statistically significant differences in detection frequency or concentrations for any of the four biomarkers of OP exposure quantified in this trial.

DISCUSSION: To our knowledge, this is the first long-term organic diet intervention study, and the first to include pregnant women. These results suggest that addition of organic produce to an individual’s diet, as compared to conventional produce, significantly reduces exposure to pyrethroid insecticides. FULL TEXT

Jusko et al., 2012

Jusko, T. A., Klebanoff, M. A., Brock, J. W., & Longnecker, M. P.; “In-utero exposure to dichlorodiphenyltrichloroethane and cognitive development among infants and school-aged children;” Epidemiology, 2012, 23(5), 689-698; DOI: 10.1097/EDE.0b013e31825fb61d.

ABSTRACT:

BACKGROUND: Dichlorodiphenyltrichloroethane (DDT) continues to be used for control of infectious diseases in several countries. In-utero exposure to DDT and dichlorodiphenyldichloroethylene (DDE) has been associated with developmental and cognitive impairment among children. We examined this association in an historical cohort in which the level of exposure was greater than in previous studies.

METHODS: The association of in-utero DDT and DDE exposure with infant and child neurodevelopment was examined in 1100 subjects in the Collaborative Perinatal Project, a prospective birth cohort enrolling pregnant women from 12 study centers in the United States from 1959 to 1965. Maternal DDT and DDE concentrations were measured in archived serum specimens. Infant mental and motor development was assessed at age 8 months using the Bayley Scales of Infant Development, and child cognitive development was assessed at age 7 years, using the Wechsler Intelligence Scale for Children.

RESULTS: Although levels of DDT and DDE were relatively high in this population (median DDT concentration, 8.9 mug/L; DDE, 24.5 mug/L), neither were related to Mental or Psychomotor Development scores on the Bayley Scales nor to Full-Scale Intelligence Quotient at 7 years of age. Categorical analyses showed no evidence of dose- response for either maternal DDT or DDE, and estimates of the association between continuous measures of exposure and neurodevelopment were indistinguishable from 0.

CONCLUSIONS: Adverse associations were not observed between maternal serum DDT and DDE concentrations and offspring neurodevelopment at 8 months or 7 years in this cohort. FULL TEXT

Duty et al., 2003

Duty, S. M., Singh, N. P., Silva, M. J., Barr, D. B., Brock, J. W., Ryan, L., Herrick, R. F., Christiani, D. C., & Hauser, R.; “The relationship between environmental exposures to phthalates and DNA damage in human sperm using the neutral comet assay;” Environmental Health Perspectives, 2003, 111(9), 1164-1169; DOI: 10.1289/ehp.5756.

ABSTRACT:

Phthalates are industrial chemicals widely used in many commercial applications. The general population is exposed to phthalates through consumer products as well as through diet and medical treatments. To determine whether environmental levels of phthalates are associated with altered DNA integrity in human sperm, we selected a population without identified sources of exposure to phthalates. One hundred sixty-eight subjects recruited from the Massachusetts General Hospital Andrology Laboratory provided a semen and a urine sample. Eight phthalate metabolites were measured in urine by using high-performance liquid chromatography and tandem mass spectrometry; data were corrected for urine dilution by adjusting for specific gravity. The neutral single-cell microgel electrophoresis assay (comet assay) was used to measure DNA integrity in sperm. VisComet image analysis software was used to measure comet extent, a measure of total comet length (micrometers); percent DNA in tail (tail%), a measure of the proportion of total DNA present in the comet tail; and tail distributed moment (TDM), an integrated measure of length and intensity (micrometers). For an interquartile range increase in specific gravity-adjusted monoethyl phthalate (MEP) level, the comet extent increased significantly by 3.6 micro m [95% confidence interval (95% CI), 0.74-6.47]; the TDM also increased 1.2 micro m (95% CI, -0.05 to 2.38) but was of borderline significance. Monobutyl, monobenzyl, monomethyl, and mono-2-ethylhexyl phthalates were not significantly associated with comet assay parameters. In conclusion, this study represents the first human data to demonstrate that urinary MEP, at environmental levels, is associated with increased DNA damage in sperm. FULL TEXT

Wenzel et al., 2018

Wenzel, A. G., Brock, J. W., Cruze, L., Newman, R. B., Unal, E. R., Wolf, B. J., Somerville, S. E., & Kucklick, J. R.; “Prevalence and predictors of phthalate exposure in pregnant women in Charleston, SC;” Chemosphere, 2018, 193, 394-402; DOI: 10.1016/j.chemosphere.2017.11.019. https://www.ncbi.nlm.nih.gov/pubmed/29154114.

ABSTRACT:

Phthalates are plasticizers commonly detected in human urine due to widespread exposure from PVC plastics, food packaging, and personal care products. Several phthalates are known antiandrogenic endocrine disruptors, which raises concern for prenatal exposure during critical windows of fetal development. While phthalate exposure is ubiquitous, certain demographics are subject to greater or lesser exposure. We sampled urine from 378 pregnant women during the second trimester of gestation living in Charleston, SC, and measured eight urinary phthalate metabolites as biomarkers of phthalate exposure: monobutyl phthalate (MBP), monobenzyl phthalate (MBzP), mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), monoethyl phthalate (MEP), monoisobutyl phthalate (MiBP), and monomethyl phthalate (MMP). Demographic data was collected from questionnaires administered at the time of specimen collection. All phthalate metabolites were detected in over 93% of urine samples. On average, concentrations were highest for MEP (median = 47.0 ng/mL) and lowest for MMP (median = 1.92 ng/mL). Sociodemographic characteristics associated with elevated phthalate concentrations included being unmarried, less educated, having a low income, high body mass index (BMI), and/or being African American. After racial stratification, age, BMI, education, and income were significantly associated with phthalate concentrations in African American women. Marital status was associated with phthalate concentrations in Caucasian women only, with greater concentrations of MBP, MEHHP, MiBP, and MMP in unmarried versus married women. Results of this cross-sectional study provide evidence for significant racial and demographic variations in phthalate exposure. FULL TEXT

Zhang et al., 2017b

Zhang, Ti , Johnson, Eric N., Mueller, Thomas C., & Willenborg, Christian J.; “Early Application of Harvest Aid Herbicides Adversely Impacts Lentil;” Agronomy Journal, 2017, 109(1), 239-248; DOI: 10.2134/agronj2016.07.0419.

ABSTRACT:

Applying harvest aid herbicides can dry down lentil (Lens culinaris Medik.) crops evenly and quickly, and can help control late-emerging weeds. However, improper application timing may reduce yield and quality, and leave unacceptable herbicide residues in seed, which can cause commercial issues when marketing lentil. The objective of this research was to determine the response of lentil to various application timings of glyphosate, saflufenacil, and the combination of these two herbicides. A field experiment consisting of a randomized complete block design was run at Saskatoon and Scott, SK, Canada in 2012, 2013, and 2014 to address the objective. Application of harvest aid herbicides before 30% seed moisture content reduced seed yield and thousand seed weight up to 25 and 8%, respectively. Moreover, application timings before 30% seed moisture resulted in lentil seed samples exceeding residue levels of 2.0 and 0.03 mg kg–1 for glyphosate and saflufenacil, respectively. Adding saflufenacil to glyphosate did not reduce glyphosate residue in lentil seed compared to glyphosate applied alone. However, this tank mixture significantly reduced seed residues of saflufenacil and improved crop desiccation compared with either glyphosate or saflufenacil applied alone. Our data lead us to conclude that a tank mix of saflufenacil+glyphosate should be recommended for crop desiccation and pre-harvest weed control in lentil over using either product alone. In addition, it is critical to ensure applications of glyphosate or saflufenacil are not made prior to 30% seed moisture in lentil crops. FULL TEXT

Zhang et al., 2017a

Zhang, Ti, Johnson, Eric N., & Willenborg, Christian J.; “Evaluation of Harvest-Aid Herbicides as Desiccants in Lentil Production;” Weed Technology, 2017, 30(3), 629-638; DOI: 10.1614/wt-d-16-00007.1.

ABSTRACT:

Desiccants are currently used to improve lentil dry-down prior to harvest. Applying desiccants at growth stages prior to maturity may result in reduced crop yield and quality, and leave unacceptable herbicide residues in seeds. There is little information on whether various herbicides applied alone or as a tank-mix with glyphosate have an effect on glyphosate residues in harvested seed. Field trials were conducted at Saskatoon and Scott, Saskatchewan, Canada, from 2012 to 2014 to determine whether additional desiccants applied alone or tank mixed with glyphosate improve crop desiccation and reduce the potential for unacceptable glyphosate residue in seed. Glufosinate and diquat tank mixed with glyphosate were the most consistent desiccants, providing optimal crop dry-down and a general reduction in glyphosate seed residues without adverse effects on seed yield and weight. Saflufenacil provided good crop desiccation without yield loss, but failed to reduce glyphosate seed residues consistently. Pyraflufen-ethyl and flumioxazin applied alone or tank mixed with glyphosate were found to be inferior options for growers as they exhibited slow and incomplete crop desiccation, and did not decrease glyphosate seed residues. Based on results from this study, growers should apply glufosinate or diquat with preharvest glyphosate to maximize crop and weed desiccation, and minimize glyphosate seed residues. FULL TEXT

Griffin et al., 2010

Griffin, James L., Boudreaux, Joseph M., & Miller, Donnie K.; “Herbicides As Harvest Aids;” Weed Science, 2017, 58(3), 355-358; DOI: 10.1614/ws-09-108.1.

ABSTRACT:

Herbicides used as harvest aids are applied at crop maturity to desiccate weed and crop foliage. Weeds present in the harvested crop can increase moisture content and foreign material, reducing grade and market price. Weeds can also delay the harvest operation and reduce harvest efficiency. Glyphosate can be used to desiccate weeds in glyphosate-resistant crops without concern for crop injury. Carfentrazone and pyraflufen-ethyl used as harvest aids can be effective in desiccating broadleaf weeds in corn and soybean. Paraquat, although effective on grass and broadleaf weeds when applied late season, can cause significant crop injury if applied too early. With expanded production of early maturing soybean cultivars in the mid-South (Arkansas, Louisiana, Mississippi, Missouri bootheel, and west Tennessee), presence of green stems, green pods, or green leaf retention, or combinations of these at harvest has increased. Interest in harvest aids has shifted to use as a crop desiccant. Paraquat also is an effective soybean desiccant, but application timing differs for indeterminate and determinate cultivars. Paraquat applied after soybean seed reached physiological maturity reduced number of green stems, pods, and retained green leaves present, allowing harvest to proceed 1 to 2 wk earlier than nontreated soybean. Seed moisture, foreign material, and seed damage also were reduced when paraquat was applied. FULL TEXT

Wigfield et al., 1994

Wigfield, Y. Y., Deneault, F., & Fillion, J.; “Residues of glyphosate and its principle metabolite in certain cereals, oilseeds, and pulses grown in Canada, 1990-1992;” Bulletin of Environmental Contamination and Toxicology, 1994, 53(4), 543-547; DOI: 10.1007/bf00199024.

ABSTRACT:

Glyphosate, sold under the trade names of Roundup R (for ground application) and Vision R (for forestry use), is a non-selective herbicide which is absorbed through the leaves and translocated throughout the whole plant. The herbicide, when applied close to harvest for late season weed control and possible harvest management benefits, can result in the presence of residues throughout the whole plant including the seed coat. In Canada, glyphosate is registered for pre-plant and post-harvest uses and until June 1991, it was not registered for direct application on crops. Diquat, a fast acting herbicide, is registered for desiccation of canola, mustard, field peas, flax, soybeans, and lentils. While diquat is effective as desiccant, it is not particularly effective in controlling perennial weeds and it is not registered for use on cereals. In June 1991, a temporary registration was granted for pre-harvest application on flax for control of quackgrass, seasonlong control of Canada thistle and perennial sow thistle and harvest management by drying down the crops. In June 1992, the same registration was granted for application on certain cereals (wheat and barley), oilseeds (canola/rapeseeds and soybeans) and pulses (peas and lentils), and in June, 1993 it was granted for malting barley. The pre-harvest use may also provide soil conservation benefits by reducing the use of cultivation as a means of weed control. The maximum residue limit (MRL) (Doliner and Stewart, 199 la) when crops are treated with the proposed label directions (single application at the rate of 0.89 kg/ha glyphosate and the time of 7-14 days before harvest) are shown in Table 1. Registration for use on beans has not been granted due to insufficient residue data.

However, because glyphosate is effective as herbicide and provides harvest management benefits, in 1990 questions were raised from Agriculture Canada field inspection staff regarding the potential misuse of the herbicide which at that time was not registered for pre-harvest use on crops. Thus a post-harvest survey was conducted to monitor glyphosate residues in these cereals, oilseeds and pulses grown during 1990-1992 period to check if the registration uses of glyphosate were being followed. This paper presents the 3-year monitoring results comprising 459 samples of 8 different crops grown in 7 different provinces in Canada. FULL TEXT

Cessna et al., 1994

Cessna, A. J., Darwent, A. L., Kirkland, K. J., Townley-Smith, L., Harker, K. N., & Lefkovitch, L. P.; “Residues of glyphosate and its metabolite AMPA in wheat seed and foliage following preharvest applications;” Canadian Journal of Plant Science, 1994, 74(3), 653-661; DOI: 10.4141/cjps94-117.

ABSTRACT:

In a 2-yr study at four locations in western Canada, residues of glyphosate and its major metabolite aminomethyl-phosphonic acid (AMPA) were measured in the seed and foliage of wheat (Triticum aestivum L.) following preharvest applications at rates of 0.45, 0.9 or 1.7 kg acid equivalent ha−1. Herbicide treatments were applied in early August to mid-September at seed moisture contents ranging from 52 to 12%. Glyphosate and AMPA residues in the seed increased as the rate of application increased, and decreased as the seed moisture content at the time of application decreased. However, when the maximum application rate of 1.7 kg ha−1 was sprayed at seed moisture contents of 40% or less, glyphosate residues in the seed were < 5 mg kg−1, the Maximum Residue Level recently established by Health Canada. Glyphosate and AMPA residues in the straw also increased with increasing application rate, but there was no consistent pattern in residues of either chemical with seed moisture content at the time of application. Physiological maturity of the crop, rainfall washoff, and application rate appeared to play important roles in determining the magnitude of glyphosate and AMPA residues in the seed and straw of wheat. Key words: Glyphosate, AMPA, residues, wheat, seed, preharvest application. FULL TEXT

Cessna et al., 2002

Cessna, A. J., Darwent, A. L., Townley-Smith, L., Harker, K. N., & Kirkland, K.; “Residues of glyphosate and its metabolite AMPA in field pea, barley and flax seed following preharvest applications;” Canadian Journal of Plant Science, 2002, 82(2), 485-489; DOI: 10.4141/p01-094.

ABSTRACT:

Maximum residue levels have been established by Health Canada for seed of several crops treated with preharvest applications of glyphosate, a common practice on the Canadian prairies. Residues of glyphosate and its major metabolite aminomethylphosphonic acid (AMPA) were determined at crop maturity in flax seed at one site in western Canada and in the seed and straw of field pea and barley at another site following preharvest applications of the herbicide. Glyphosate was applied at rates of 0.45, 0.9 and 1.7 kg ha-1 to each crop in early August to mid-September at four stages of crop development. In all crops, mean residues of glyphosate and AMPA increased with increasing application rate of glyphosate and decreased when the herbicide was applied at later stages of crop development. FULL TEXT

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