Analytical Methods - HH-RA.org

Bibliography Tag: analytical methods

Yusa et al., 2015

Yusa, V., Millet, M., Coscolla, C., & Roca, M.; “Analytical methods for human biomonitoring of pesticides. A review;” Analytica Chimica Acta, 2015, 891, 15-31; DOI: 10.1016/j.aca.2015.05.032.

ABSTRACT:

Biomonitoring of both currently-used and banned-persistent pesticides is a very useful tool for assessing human exposure to these chemicals. In this review, we present current approaches and recent advances in the analytical methods for determining the biomarkers of exposure to pesticides in the most commonly used specimens, such as blood, urine, and breast milk, and in emerging non-invasive matrices such as hair and meconium. We critically discuss the main applications for sample treatment, and the instrumental techniques currently used to determine the most relevant pesticide biomarkers. We finally look at the future trends in this field. FULL TEXT

Zhang et al., 2020

Zhang, M., Chu, Y., Meng, Q., Ding, R., Shi, X., Wang, Z., He, Y., Zhang, J., Liu, J., Zhang, J., Yu, J., Kang, Y., & Wang, J.; “A quasi-paired cohort strategy reveals the impaired detoxifying function of microbes in the gut of autistic children;” Science Advances, 2020, 6(43); DOI: 10.1126/sciadv.aba3760.

ABSTRACT:

Growing evidence suggests that autism spectrum disorder (ASD) is strongly associated with dysbiosis in the gut microbiome, with the exact mechanisms still unclear. We have proposed a novel analytic strategy-quasi-paired cohort-and applied it to a metagenomic study of the ASD microbiome. By comparing paired samples of ASD and neurotypical subjects, we have identified significant deficiencies in ASD children in detoxifying enzymes and pathways, which show a strong correlation with biomarkers of mitochondrial dysfunction. Diagnostic models based on these detoxifying enzymes accurately distinguished ASD individuals from controls, and the dysfunction score inferred from the model increased with the clinical rating scores of ASD. In summary, our results suggest a previously undiscovered potential role of impaired intestinal microbial detoxification in toxin accumulation and mitochondrial dysfunction, a core component of ASD pathogenesis. These findings pave the way for designing future therapeutic strategies to restore microbial detoxification capabilities for patients with ASD. FULL TEXT

Ruden and Grandjean, 2018

Mie, A., Ruden, C., & Grandjean, P.; “Safety of Safety Evaluation of Pesticides: developmental neurotoxicity of chlorpyrifos and chlorpyrifos-methyl;” Environmental Health, 2018, 17(1), 77; DOI: 10.1186/s12940-018-0421-y.

ABSTRACT:

Authorization of pesticides for market release requires toxicity testing on animals, typically performed by test laboratories on contract with the pesticide producer. The latter provides the results and summary to the regulatory authorities. For the commonly used pesticide chlorpyrifos, an industry-funded toxicity study concludes that no selective effects on neurodevelopment occur even at high exposures. In contrast, the evidence from independent studies points to adverse effects of current exposures on cognitive development in children. We reviewed the industry-funded developmental neurotoxicity test data on chlorpyrifos and the related substance chlorpyrifos-methyl. We noted treatment-related changes in a brain dimension measure for chlorpyrifos at all dose levels tested, although not been reported in the original test summary. We further found issues which inappropriately decrease the ability of the studies to reveal true effects, including a dosage regimen that resulted in too low exposure of the nursing pups for chlorpyrifos and possibly for chlorpyrifos-methyl, and a failure to detect any neurobehavioral effects of lead nitrate used as positive control in the chlorpyrifos study. Our observations thus suggest that conclusions in test reports submitted by the producer may be misleading. This discrepancy affects the ability of regulatory authorities to perform a valid and safe evaluation of these pesticides. The difference between raw data and conclusions in the test reports indicates a potential existence of bias that would require regulatory attention and possible resolution. FULL TEXT

Malone and Foster, 2019

Malone, M., & Foster, E.; “A mixed-methods approach to determine how conservation management programs and techniques have affected herbicide use and distribution in the environment over time;” Science of The Total Environment, 2019, 660, 145-157; DOI: 10.1016/j.scitotenv.2018.12.266.

ABSTRACT:

No-till agriculture has the ability to reduce fuel consumption, increase soil moisture, reduce soil erosion and increase organic matter. However, it remains unclear whether it increases herbicide use overall in the long term for communities that use no-till as their primary source of conservation agriculture. The preponderance of literature suggests that no-till has increased herbicide use, but it is difficult to quantify how much herbicide has increased in a given location and to directly correlate changes in herbicide use to changes in soil and water quality. This paper provides several methods to determine how herbicide use has changed over time in an agricultural community in Oregon that switched over to no-till in the late 1990s and early 2000s. These methods include: spatial analysis of remote sensing satellite imagery of vegetation health along streams; use of a drone fitted with an agricultural camera to detect vegetation health; and soil, sediment, and water sampling for the most commonly used herbicides in the study area. By using these methods, this study shows where stream vegetation health continues to be an issue in the agricultural community, and where concentrations of a commonly used herbicide in the community may be impacting human and ecological health. This study has important implications for impacts to soil and water quality over time in agricultural communities, as many researchers have noted the need to determine the long term effects of conversion to no-till and other forms of conservation agriculture. By providing these methods, communities heavily engaged in multiple forms of conservation agriculture may be able to track herbicide use changes in real time and on shorter decadal time spans in places where conservation agriculture is practiced. FULL TEXT

Apel et al., 2020

Apel, P., Rousselle, C., Lange, R., Sissoko, F., Kolossa-Gehring, M., & Ougier, E.; “Human biomonitoring initiative (HBM4EU) – Strategy to derive human biomonitoring guidance values (HBM-GVs) for health risk assessment;” International Journal of Hygiene and Environmental Health, 2020, 230, 113622; DOI: 10.1016/j.ijheh.2020.113622.

ABSTRACT:

The European Joint Program “HBM4EU” is a joint effort of 30 countries and the European Environment Agency, co-funded under the European Commission’s Horizon 2020 program, for advancing and implementing human biomonitoring (HBM) on a European scale and for providing scientific evidence for chemical policy making. One important outcome will be a Europe-wide improvement and harmonization of health risk assessment following the coordinated derivation or update of health-related guidance values referring to the internal body burden. These guidance values – named HBM guidance values or HBM-GVs – can directly be compared with HBM data. They are derived within HBM4EU for priority substances identified by the HBM4EU chemicals prioritization strategy based on existing needs to answer policy relevant questions as raised by national and EU policy makers. HBM-GVs refer to both the general population and occupationally exposed adults. Reports including the detailed reasoning for the values’ proposals are subjected to a consultation process within all partner countries of the consortium to reach a broad scientific consensus on the derivation approach and on the derived values. The final HBM-GVs should be applied first within the HBM4EU project, but may also be useful for regulators and risk assessors outside this project. The subsequent adoption of derived HBM-GVs at EU-level needs to be discussed and decided within the responsible EU bodies. Nevertheless, the establishment of HBM-GVs as part of HBM4EU is already a step forward in strengthening HBM-based policy efforts for public and occupational health. The strategy for deriving HBM-GVs which is based on already existing approaches from the German HBM Commission, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) as well as from the US-based scientific consultant Summit Toxicology, the allocation of a level of confidence to the derived values, and the consultation process within the project are comprehensively described to enlighten the work accomplished under the HBM4EU initiative. FULL TEXT

Haas et al., 2015

Haas, D. M., Parker, C. B., Wing, D. A., Parry, S., Grobman, W. A., Mercer, B. M., Simhan, H. N., Hoffman, M. K., Silver, R. M., Wadhwa, P., Iams, J. D., Koch, M. A., Caritis, S. N., Wapner, R. J., Esplin, M. S., Elovitz, M. A., Foroud, T., Peaceman, A. M., Saade, G. R., Willinger, M., Reddy, U. M., & NuMo, M. b study; “A description of the methods of the Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be (nuMoM2b);” American Journal of Obstetrics & Gynecology, 2015, 212(4), 539 e531-539 e524; DOI: 10.1016/j.ajog.2015.01.019.

ABSTRACT:

OBJECTIVE: The primary aim of the “Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be” is to determine maternal characteristics, which include genetic, physiologic response to pregnancy, and environmental factors that predict adverse pregnancy outcomes.

STUDY DESIGN: Nulliparous women in the first trimester of pregnancy were recruited into an observational cohort study. Participants were seen at 3 study visits during pregnancy and again at delivery. We collected data from in-clinic interviews, take-home surveys, clinical measurements, ultrasound studies, and chart abstractions. Maternal biospecimens (serum, plasma, urine, cervicovaginal fluid) at antepartum study visits and delivery specimens (placenta, umbilical cord, cord blood) were collected, processed, and stored. The primary outcome of the study was defined as pregnancy ending at <37+0 weeks’ gestation. Key study hypotheses involve adverse pregnancy outcomes of spontaneous preterm birth, preeclampsia, and fetal growth restriction.

RESULTS: We recruited 10,037 women to the study. Basic characteristics of the cohort at screening are reported.

CONCLUSION: The “Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be” cohort study methods and procedures can help investigators when they plan future projects.

FULL TEXT

Scholze et al., 2020

Scholze, M., Taxvig, C., Kortenkamp, A., Boberg, J., Christiansen, S., Svingen, T., Lauschke, K., Frandsen, H., Ermler, S., Hermann, S. S., Pedersen, M., Lykkeberg, A. K., Axelstad, M., & Vinggaard, A. M.; “Quantitative in Vitro to in Vivo Extrapolation (QIVIVE) for Predicting Reduced Anogenital Distance Produced by Anti-Androgenic Pesticides in a Rodent Model for Male Reproductive Disorders;” Environ Health Perspect, 2020, 128(11), 117005; DOI: 10.1289/EHP6774.

ABSTRACT:

BACKGROUND: Many pesticides can antagonize the androgen receptor (AR) or inhibit androgen synthesis in vitro but their potential to cause reproductive toxicity related to disruption of androgen action during fetal life is difficult to predict. Currently no approaches for using in vitro data to anticipate such in vivo effects exist. Prioritization schemes that limit unnecessary in vivo testing are urgently needed.

OBJECTIVES: The aim was to develop a quantitative in vitro to in vivo extrapolation (QIVIVE) approach for predicting in vivo anti-androgenicity arising from gestational exposures and manifesting as a shortened anogenital distance (AGD) in male rats.

METHODS: We built a physiologically based pharmacokinetic (PBK) model to simulate concentrations of chemicals in the fetus resulting from maternal dosing. The predicted fetal levels were compared with analytically determined concentrations, and these were judged against in vitro active concentrations for AR antagonism and androgen synthesis suppression.

RESULTS: We first evaluated our model by using in vitro and in vivo anti-androgenic data for procymidone, vinclozolin, and linuron. Our PBK model described the measured fetal concentrations of parent compounds and metabolites quite accurately (within a factor of five). We applied the model to nine current-use pesticides, all with in vitro evidence for anti-androgenicity but missing in vivo data. Seven pesticides (fludioxonil, cyprodinil, dimethomorph, imazalil, quinoxyfen, fenhexamid, o-phenylphenol) were predicted to produce a shortened AGD in male pups, whereas two (lambda-cyhalothrin, pyrimethanil) were anticipated to be inactive. We tested these expectations for fludioxonil, cyprodinil, and dimethomorph and observed shortened AGD in male pups after gestational exposure. The measured fetal concentrations agreed well with PBK-modeled predictions.

DISCUSSION: Our QIVIVE model newly identified fludioxonil, cyprodinil, and dimethomorph as in vivo anti-androgens. With the examples investigated, our approach shows great promise for predicting in vivo anti-androgenicity (i.e., AGD shortening) for chemicals with in vitro activity and for minimizing unnecessary in vivo testing. FULL TEXT

Franke et al., 2020

Franke, A. A., Li, X., & Lai, J. F.; “Analysis of glyphosate, aminomethylphosphonic acid, and glufosinate from human urine by HRAM LC-MS;” Analytical and Bioanalytical Chemistry, 2020; DOI: 10.1007/s00216-020-02966-1.

ABSTRACT:

Aminomethylphosphonic acid (AMPA) is the main metabolite of glyphosate (GLYP) and phosphonic acids in detergents. GLYP is a synthetic herbicide frequently used worldwide alone or together with its analog glufosinate (GLUF). The general public can be exposed to these potentially harmful chemicals; thus, sensitive methods to monitor them in humans are urgently required to evaluate health risks. We attempted to simultaneously detect GLYP, AMPA, and GLUF in human urine by high-resolution accurate-mass liquid chromatography mass spectrometry (HRAM LC-MS) before and after derivatization with 9-fluorenylmethoxycarbonyl chloride (Fmoc-Cl) or 1-methylimidazole-sulfonyl chloride (ImS-Cl) with several urine pre-treatment and solid phase extraction (SPE) steps. Fmoc-Cl derivatization achieved the best combination of method sensitivity (limit of detection; LOD) and accuracy for all compounds compared to underivatized urine or ImS-Cl-derivatized urine. Before derivatization, the best steps for GLYP involved 0.4 mM ethylenediaminetetraacetic acid (EDTA) pre-treatment followed by SPE pre-cleanup (LOD 37 pg/mL), for AMPA involved no EDTA pre-treatment and no SPE pre-cleanup (LOD 20 pg/mL) or 0.2-0.4 mM EDTA pre-treatment with no SPE pre-cleanup (LOD 19-21 pg/mL), and for GLUF involved 0.4 mM EDTA pre-treatment and no SPE pre-cleanup (LOD 7 pg/mL). However, for these methods, accuracy was sufficient only for AMPA (101-105%), while being modest for GLYP (61%) and GLUF (63%). Different EDTA and SPE treatments prior to Fmoc-Cl derivatization resulted in high sensitivity for all analytes but satisfactory accuracy only for AMPA. Thus, we conclude that our HRAM LC-MS method is suited for urinary AMPA analysis in cross-sectional studies. FULL TEXT

Connolly et al., 2020

Connolly, A., Coggins, M. A., & Koch, H. M.; “Human Biomonitoring of Glyphosate Exposures: State-of-the-Art and Future Research Challenges;” Toxics, 2020, 8(3); DOI: 10.3390/toxics8030060. https://www.ncbi.nlm.nih.gov/pubmed/32824707.

ABSTRACT:

Glyphosate continues to attract controversial debate following the International Agency for Research on Cancer carcinogenicity classification in 2015. Despite its ubiquitous presence in our environment, there remains a dearth of data on human exposure to both glyphosate and its main biodegradation product aminomethylphosphonic (AMPA). Herein, we reviewed and compared results from 21 studies that use human biomonitoring (HBM) to measure urinary glyphosate and AMPA. Elucidation of the level and range of exposure was complicated by differences in sampling strategy, analytical methods, and data presentation. Exposure data is required to enable a more robust regulatory risk assessment, and these studies included higher occupational exposures, environmental exposures, and vulnerable groups such as children. There was also considerable uncertainty regarding the absorption and excretion pattern of glyphosate and AMPA in humans. This information is required to back-calculate exposure doses from urinary levels and thus, compared with health-based guidance values. Back-calculations based on animal-derived excretion rates suggested that there were no health concerns in relation to glyphosate exposure (when compared with EFSA acceptable daily intake (ADI)). However, recent human metabolism data has reported as low as a 1% urinary excretion rate of glyphosate. Human exposures extrapolated from urinary glyphosate concentrations found that upper-bound levels may be much closer to the ADI than previously reported. FULL TEXT

Stephenson and Harris, 2016

Stephenson, C. L., & Harris, C. A.; “An assessment of dietary exposure to glyphosate using refined deterministic and probabilistic methods;” Food and Chemical Toxicology, 2016, 95, 28-41; DOI: 10.1016/j.fct.2016.06.026.

ABSTRACT:

Glyphosate is a herbicide used to control broad-leaved weeds. Some uses of glyphosate in crop production can lead to residues of the active substance and related metabolites in food. This paper uses data on residue levels, processing information and consumption patterns, to assess theoretical lifetime dietary exposure to glyphosate. Initial estimates were made assuming exposure to the highest permitted residue levels in foods. These intakes were then refined using median residue levels from trials, processing information, and monitoring data to achieve a more realistic estimate of exposure. Estimates were made using deterministic and probabilistic methods. Exposures were compared to the acceptable daily intake (ADI)-the amount of a substance that can be consumed daily without an appreciable health risk. Refined deterministic intakes for all consumers were at or below 2.1% of the ADI. Variations were due to cultural differences in consumption patterns and the level of aggregation of the dietary information in calculation models, which allows refinements for processing. Probabilistic exposure estimates ranged from 0.03% to 0.90% of the ADI, depending on whether optimistic or pessimistic assumptions were made in the calculations. Additional refinements would be possible if further data on processing and from residues monitoring programmes were available. FULL TEXT

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