Mesnage, Robin, “Effects of dietary exposures to pesticide residues on the gut microbiome,” 2019, Presented 10/30/2019 at the London Microbiome Meeting 2019, Great Hall, King’s College London Strand Campus.
SUMMARY:
The gut microbiota: a major player in the toxicity of environmental pollutants?
Chiu, Y. H., Williams, P. L., Gillman, M. W., Gaskins, A. J., Minguez-Alarcon, L., Souter, I., Toth, T. L., Ford, J. B., Hauser, R., Chavarro, J. E., & Team, Earth Study; “Association Between Pesticide Residue Intake From Consumption of Fruits and Vegetables and Pregnancy Outcomes Among Women Undergoing Infertility Treatment With Assisted Reproductive Technology;” JAMA Internal Medicine, 2018, 178(1), 17-26; DOI: 10.1001/jamainternmed.2017.5038.
ABSTRACT:
IMPORTANCE:
Animal experiments suggest that ingestion of pesticide mixtures at environmentally relevant concentrations decreases the number of live-born offspring. Whether the same is true in humans is unknown. Objective: To examine the association of preconception intake of pesticide residues in fruits and vegetables (FVs) with outcomes of infertility treatment with assisted reproductive technologies (ART).
DESIGNT, SETTING, AND PARTICIPANTS:
This analysis included 325 women who completed a diet assessment and subsequently underwent 541 ART cycles in the Environment and Reproductive Health (EARTH) prospective cohort study (2007-2016) at a fertility center at a teaching hospital. We categorized FVs as having high or low pesticide residues using a validated method based on surveillance data from the US Department of Agriculture. Cluster-weighted generalized estimating equations were used to analyze associations of high- and low-pesticide residue FV intake with ART outcomes.
MAIN OUTCOMES AND MEASURES:
Adjusted probabilities of clinical pregnancy and live birth per treatment cycle.
RESULTS:
In the 325 participants (mean [SD] age, 35.1 [4.0] y; body mass index, 24.1 [4.3]), mean (SD) intakes of high- and low-pesticide residue FVs were 1.7 (1.0) and 2.8 (1.6) servings/d, respectively. Greater intake of high-pesticide residue FVs was associated with a lower probability of clinical pregnancy and live birth. Compared with women in the lowest quartile of high-pesticide FV intake (<1.0 servings/d), women in the highest quartile (>/=2.3 servings/d) had 18% (95% CI, 5%-30%) lower probability of clinical pregnancy and 26% (95% CI, 13%-37%) lower probability of live birth. Intake of low-pesticide residue FVs was not significantly related to ART outcomes.
CONCLUSIONS AND RELEVANCE:
Higher consumption of high-pesticide residue FVs was associated with lower probabilities of pregnancy and live birth following infertility treatment with ART. These data suggest that dietary pesticide exposure within the range of typical human exposure may be associated with adverse reproductive consequences. FULL TEXT
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
Kleter, Gijs A, Unsworth, B, & Harris, Caroline A; “The impact of altered herbicide residues in transgenic herbicide-resistant crops on standard setting for herbicide residues;” Pest Management Science, 2011, 67, 1193-1210; DOI: 10.1002/ps.2128.
ABSTRACT:
The global area covered with transgenic (genetically modified) crops has rapidly increased since their introduction in the mid-1990s.Most of these crops have been rendered herbicide resistant, for which it can be envisaged that the modification has an impact on the profile and level of herbicide residues within these crops. In this article, the four main categories of herbicide resistance, including resistance to acetolactate-synthase inhibitors, bromoxynil, glufosinate and glyphosate, are reviewed. The topics considered are the molecular mechanism underlying the herbicide resistance, the nature and levels of the residues formed and their impact on the residue definition and maximum residue limits (MRLs) defined by the Codex Alimentarius Commission and national authorities. No general conclusions can be drawn concerning the nature and level of residues, which has to be done on a case-by-case basis. International residue definitions and MRLs are still lacking for some herbicide–crop combinations, and harmonisation is therefore recommended. FULL TEXT
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, 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
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
Pornprom, T., Sukcharoenvipharat, W., & Sansiriphun, D.; “Weed control with pre-emergence herbicides in vegetable soybean (Glycine max L. Merrill);” Crop Protection, 2010, 29(7), 684-690; DOI: 10.1016/j.cropro.2010.02.003.
ABSTRACT:
Field and laboratory experiments were conducted in the early and late rainy seasons in Thailand to evaluate the effect of pre-emergence application of herbicides and determine the herbicide residues on vegetable soybean (Glycine max L. Merrill cv. No. 75) production. No visible crop injury was observed after application of alachlor 469 g a.i./ha, clomazone 1080 g a.i./ha, metribuzin 525 g a.i./ha, pendimethalin 1031.25 g a.i./ha, tank-mixed clomazone 960 g a.i./ha þpendimethalin 928 g a.i./ha, or tank-mixed metribuzin 350 g a.i./haþ pendimethalin 928 g a.i./ha. However, acetochlor 1875 g a.i./ha, isoxaflutole 75 g a.i./ha, and oxadiazon 1000 g a.i./ha caused visible crop injury. Plant bioassay of herbicide residues in the soil after harvest showed no phytotoxic effect on baby corn (Zea mays Linn. cv. Suwan 3), cucumber (Cucumis sativus L. cv. Pijit 1), pak choi (Brassica chinensis Jusl. cv. Chinensis), and soybean (G. max L. Merrill cv. CM 60). Gas Chromatography-Mass Spectrometry (GC–MS) analysis showed no significant herbicide residues on crop yield (or MRLs< 0.01 ppm) for all herbicides used in this study. The application of metribuzin at 525 g a.i./ha was sufficient to provide satisfactory full-season control of several weed species and gave the highest crop yield. In addition, pendimethalin at 1031.25 g a.i./ha, and tankmixed metribuzin at 350 g a.i./ha þ pendimethalin at 928 g a.i./ha can provide a similar level of weed control as an alternative to reduce herbicide dosage thereby increasing food and environmental safety in vegetable soybean production. FULL TEXT
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, 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