Comparative effects of the formulation of glyphosate-surfactant herbicides on hemodynamics in swine

Abstract

Introduction. Most of the glyphosate-surfactant herbicides (GlySH) are formulated commercial products containing isopropylamine (IPA) salt of glyphosate (IPAG), variable amount of a surfactant, and water. Although glyphosate is only slightly toxic to rats, ingestion of GlySH may lead to severe effects, including death, in humans. We conducted a study to evaluate the cardiovascular effects of the components of GlySH. Methods. We used five groups of male piglets, each receiving infusion of normal saline (control), glyphosate in NaOH base, IPA, IPAG, and polyoxyethyleneamine (POEA), respectively. We chose concentrations that are similar to those in the commonly used GlySH (41% of IPAG and 15% surfactant). Results. We found that IPAG reduced the mean arterial blood pressure (MABP) and left-ventricular stroke work index (LVSWI) during the infusion, but both recovered gradually. It also decreased the cardiac index but increased the pulmonary capillary wedge pressure, central venous pressure (CVP), and mean pulmonary arterial pressure (MPAP). POEA infusion reduced the cardiac index and LVSWI, but not the MABP. It also increased the pulmonary capillary wedge pressure, CVP, MPAP, and pulmonary vascular resistance index. IPA increased the MABP, which was higher than those in the control, IPAG, and POEA groups. Glyphosate in NaOH base infusion did not affect the hemodynamics but slightly reduced the blood pH and base excess (BE) values. POEA and IPAG also resulted in metabolic acidosis, with lactate formation and decreased BE values. Conclusion. We conclude that both POEA and IPAG infusion affected hemodynamics and resulted in death in piglets, whereas glyphosate (NaOH base) had no similar effects.

Keywords:

• Glyphosate
• Isopropylamine salt of glyphosate
• Polyoxyethyleneamine
• Glyphosate-surfactant herbicides
• Hemodynamics
• Poisoning

Acknowledgments

This study was supported by the National Science Council, Taiwan, R.O.C (Grant NSC92-2320-B–006-102) and the National Cheng Kung University Hospital (Grant NCKU93-003). The authors thank Cheng-Kuo Lai at the Army N.B.C. Protection Research Center for his assistance in performing the glyphosate analysis and Jung-Hua Fang at the Laboratory Animal Center, National Cheng Kung University, for his assistance in performing the experiments.