Glyphosate-surfactant herbicide products containing glyphosate potassium salt can cause fatal hyperkalemia if ingested in massive amounts

Application of probe electrospray ionization-tandem mass spectrometry to ultra-rapid determination of glufosinate and glyphosate in human serum

Glufosinate and glyphosate, which are non-selective herbicides that include an amino acid moiety in their structures, are frequently used worldwide to control unwanted vegetation. Unfortunately, these readily available herbicides are also used by people to commit suicide, and thus represent important chemicals of interest in the fields of clinical medicine and forensics. Because of the high water solubility of these herbicides, most analytical methods for their detection require a derivatization step, which results in longer analysis times. Therefore, derivatization-based methods do not currently contribute to judgements on treatment decisions in emergency medicine. In this study, we addressed this limiting factor by developing an ultra-rapid and simple analytical technique using a combination of probe electrospray ionization (PESI) and tandem mass spectrometry (MS/MS), which gives quantitative results within 0.3 min. Herbicide standards were added to human serum that was then subjected to analysis (N = 5 per concentration). The analysis was repeated daily over eight consecutive days. The limit of detection (LOD) was 0.59 μg/mL for glufosinate and 0.20 μg/mL for glyphosate. The limit of quantitation (LOQ), i.e., the lowest point on the calibration curves, was 1.56 μg/mL for both the herbicides. The matrix effects were observed at three different concentrations (between 95.7%-104% for glufosinate, and between 90.7%-95.7% for glyphosate). When applied to samples taken from actual poisoning cases (six samples for each herbicide), the present method gave almost the same quantitative values as those obtained by conventional high-performance liquid chromatography with fluorescence detection. Thus, we believe that PESI-MS/MS could emerge as a rapid diagnosis method in the clinical emergency field.

Global research production in glyphosate intoxication from 1978 to 2015: A bibliometric analysis

BACKGROUND

Glyphosate (N-phosphonomethylglycine) has been used as a broad-spectrum herbicide that has been widely used in the agricultural industry and also available for home use. The main aim of this study is to present a general overview of glyphosate intoxication-related publications from its introducing since the early 1970s using bibliometric technique.

METHODS

On June 23, 2016, a literature search of the Scopus database was performed. We then extracted and analyzed the data using well-established qualitative and quantitative bibliometric indices: Publication year, affiliation, document type, country name, subject category, journal name, publishing language, and collaboration and citation patterns.

RESULTS

We recognized a total of 3735 publications on glyphosate published between 1973 and 2015. There were 875 publications related to glyphosate intoxication in the Scopus database published between 1978 and 2015. Articles (757) comprised 86.5% of the total publications, followed by reviews (41; 4.7%). Most publications were published in English (87.9%), followed by Portuguese (6.6%). The number of publications related to glyphosate intoxication increased from 44 in 1978-1987 up to 152 in 1996-2005 and then quadrupled in 2006-2015. The United States was the leading country with 180 documents representing 20.6%, followed by Brazil (120; 13.7%), Canada (78; 8.9%), Argentina (61; 7.0%), and France (57; 6.5%). The 85.6% of the publications was cited, and the average of citation per document was 17.13 with h-index of 55. Furthermore, the United States achieved the highest h-index of 33. Most of the global international collaborations are made with researchers from the United States, who collaborated with 23 countries/territories in 44 publications.

CONCLUSIONS

The trends in global glyphosate-related research between 1978 and 2015 were evaluated by a bibliometric technique. Results showed that English was the leading publishing language, and the major publication type was original article. Findings showed that number of research publications related to glyphosate intoxication increased significantly in the last decade. The United States and Brazil are the two most productive countries in research on glyphosate intoxication. This study will be beneficial to policy makers by identifying areas that need greater investment and research funding to target appropriate agriculture sectors so as to improve glyphosate safety in a global setting.

Prognostic Factors in Emergency Department Patients with Glyphosate Surfactant Intoxication: Point-of-Care Lactate Testing

An increasing number of suicide attempts involve the ingestion of glyphosate surfactant; hence, clinical toxicologists may encounter severe cases of glyphosate surfactant intoxication. In several other clinical conditions, serum lactate is used to predict outcome. We investigated the relationship between lactate levels and 30-day mortality from glyphosate surfactant poisoning. This retrospective analysis involved 232 patients who were admitted to the emergency department after acute glyphosate surfactant poisoning between January 2004 and June 2014. We used a receiver operating characteristic (ROC) curve to define the optimal cut-off point for lactate levels. A Kaplan-Meier 30-day survival curve was then analysed in terms of the defined cut-off level. We used multi-variate Cox proportional hazards regression analysis to determine the risk factors for 30-day mortality. Of the 232 patients, 29 died, yielding a case fatality rate of 12.5%. Lactate was significantly higher in non-survivors (6.5 ± 3.1 mmol/L) than in survivors (3.3 ± 2.2 mmol/L; p < 0.001), and elevated lactate was significantly associated with 30-day mortality. The area under the ROC curve of lactate levels was 0.836 [95% confidence interval (CI): 0.716-0.869]. Lactate levels higher than 4.7 mmol/L were associated with increased mortality in multi-variable analysis (hazard ratio: 3.2; 95% CI: 1.1-8.7). Besides lactate, age >59 years, corrected QT interval >495 ms and potassium >5.5 mmol/L were independent risk factors for 30-day mortality. Lactate is an independent predictor of 30-day mortality in patients with glyphosate surfactant poisoning. Early measurement of lactate levels may be a simple and practical way to assess the severity of intoxication.

A multicenter retrospective survey of poisoning after ingestion of herbicides containing glyphosate potassium salt or other glyphosate salts in Japan

INTRODUCTION

A multicenter retrospective survey of patients poisoned by herbicides containing glyphosate salts in Japan was conducted to identify differences in symptoms and outcome of poisoning.

METHODS

Participants were patients who were transported to emergency facilities between October 2006 and March 2014 after consuming herbicides containing glyphosate potassium salt (GlyK(+)) (the K-group) or other glyphosate salts (the O-group). Questionnaires were mailed to 38 emergency facilities that agreed to participate in the study.

RESULTS

Serum potassium levels upon arrival were significantly higher (p < 0.01), and abnormal electrocardiogram findings were significantly more common (p < 0.01) in the K-group (n = 55) than in the O-group (n = 62). Conversely, acute lung injury (ALI) including acute respiratory distress syndrome (ARDS) (p = 0.05) and liver injury (LI) (p < 0.01) were significantly more common during hospitalization in the O-group, although no significant differences in the duration of hospital stay (p = 0.92) or outcomes (p = 0.95) were observed between the two groups.

DISCUSSION AND CONCLUSION

The ingestion of products containing glyphosate isopropylamine or ammonium salts, and polyoxyethyleneamine (POEA) as a surfactant, can cause severe organ injury. Physicians should note that the ingestion of products containing glyphosate potassium salt and surfactants other than POEA can cause hyperkalemia, potentially leading to fatal arrhythmias or cardiac arrest.