DIFFERENT DISTRIBUTION OF PARAQUAT AND DIQUAT IN HUMAN POISONING CASES AFTER INGESTION OF A COMBINED HERBICIDE

This report describes a slight difference in the rate of decrease of s erum paraquat and diquat concentrations in eight human cases of poison ing by the herbicide PreegloxL (containing paraquatCl(2), 5% and diqua tBr(2), 7%) and the distribution of each in three autopsied cases. The re was no variation between the serum concentrations of paraquat and d iquat within 24 h after ingestion, but paraquat remained at a slightly higher concentration than diquat after more than 24 h. The decrease o f urinary paraquat and diquat concentrations was almost the same durin g the 24-h determination period. In three autopsied cases, diquat conc entrations in the tissues were relatively lower than those of paraquat , except in bile. Paraquat and diquat were unevenly distributed in var ious tissues and fluids, but the distribution patterns of each in any particular tissues were quite similar. As no difference was observed i n the decrease of urinary paraquat and diquat, the much higher concent ration of diquat in bile indicates that bile may be one of the effecti ve factors in lowering the concentration of diquat in serum and in tis sues of the human body long after ingestion.