ABSTRACT
The exposure levels of nine spray-operators in apple orchards to Fenitrothion (MEP) was measured. The pesticide was sprayed in the form of a 1, 000-fold diluted solution of a 40% MEP wettable powder by using power sprayers.<BR>The operators were wearing protective non-woven clothes, masks (Sumitomo 3M 1780) and rubber gloves.<BR>The estimated exposure amount of MEP per operator was 217mg on average when a sprayer with a short rod (50-70 cm) was used. In the case of using a long rod (100-120 cm), the amount was less, indicating 44mg on average.<BR>The estimated amount of MEP penetrating the operator's clothing was 7.6mg on average, ranging from 1.2 to 23.9mg.<BR>The penetration rate averaged 6.3%.<BR>We calculated the MEP concentration in the air around the worker's mouth estimated from the amounts of MEP on the masks and from those in the sampling columns. The results averaged 0.258 mg/m<SUB>3</SUB> and 0.022 mg/m<SUB>3</SUB>, respectively.<BR>MEP was detected in blood samples from all the operators (0.0004-0.0222 ppm) immediately after the spray work and in blood samples from four of the nine operators (0.0004-0.0009 ppm) after one day, but not detected in any of the nine blood samples after three days.<BR>A decrease in blood ChE activities of the operators was not observed.<BR>The amount of MEP absorbed into the operator's body was calculated to be 0.34 to 2.59 mg. These calculations were based on the amount of the metabolites (converted into nitro-m-cresol) in the urine samples collected from the operators over a period of 24 hours after the spray work. However, the metabolites were detected in the spot urine samples of only one of the nine operators after three days and in none of the spot samples after seven days.<BR>These results show that a small amount of MEP was absorbed into the operator's body, suggesting that the spray-operator should not do the spray work day after day. However, from the point of view of the percutaneous and inhalation toxicity of MEP, we concluded that the sprayoperators were not affected by MEP exposure in this case.
ABSTRACT
There have been hardly any cases of paraquat poisoning during normal use of paraquat as a herbicide, but there have been a number of deaths or cases of serious poisoning due to ingestion of paraquat products as the result of suicidal intent or accidents, and the survival rate is extremely low. To prevent the occurrence of paraquat poisoning, some experiments have been conducted in which emetics were added to paraquat products.<BR>In this study, we determined the efficacy of including Triazolopyrimidine compound (pp) as an emetic in a paraquat product, when it was orally administered to dogs under the starved (condition A) or unstarved (condition B) conditions. When paraquat was orally given to the dogs (40 mg/kg body weight) under condition A, emesis occured four to six hours after the dosing. However, in the case of giving a dose of the mixed solution of paraquat and pp (PQ 40mg/kg, pp 2mg/kg), vomiting took place after four to six minutes (vomited rate of PQ: 86.4%) and seven to twenty minutes (vomited rate of PQ: 61.2%) under conditions A and B respectively. The average survival period in the case of the paraquat dosing was fifteen days and six days under conditions A and B respectively. However, in the case of giving a dose of the mixed solution of paraquat and pp, it was more than 20 days and 12.7 days under conditions A and B respectively.<BR>The results of the experiment suggest that the inclusion of emetics is one of the effective means of preventing paraquat poisoning. As the amount of ingested paraquat is usually large in the case of suicidal intention, it is conceivable that an amount greater than the lethal dose will remain in the gastrointestinal system even if the emetic included in the paraquat produces vomiting in patients. Since the inclusion of emetics in paraquat products leads to an early occurrence of vomiting in the victim, the chances of finding him or her earlier should be increased. This would, in turn, make earlier treatment possible.
ABSTRACT
While there are not any effective antidotes for paraquat poisoning up to this time, several procedures such as gastric lavage, dosing of emetics and adsorbents, hemodialysis, peritoneal dialysis and hemoperfusion have been applied in treatment of paraquat intoxication.<BR>In this study, we determined efficacy of the combined application of oral administration of an adsorbent (Adsorbin) and hemoperfusion using activated charcoal (HEMOSORBA: activated charcoal coated collodion, The ASAHI Medical Co.) in dogs being given orally paraquat in the amount of 40 mg per kg of the body weight.<BR>Efficacy of the treatments was in order of the combined application of dosing Adsorbin and the hemoperfusion with Hemosorba, single use of dosing Adsorbin and single application of the hemoperfusion.<BR>Oral administration of the adsorbent was carried out only once, either one hour or three hours after forced dosing of paraquat, and the hemoperfusion was started either one or three hours after paraquat dosing and continued for six hours in each case.<BR>Effectiveness of the treatment on the survival-time was superior in the case of dosing the adsorbent and starting the hemoperfusion one hour after paraquat administration.<BR>As a sign of developing lung fibrosis was found on histopathological observation in dogs survived for twenty days after starting the experiment, even in case of the combined treatment with the best results, observation of longer period seems to be necessary for obtaining more information after treatment. And it is furthermore advisable that the treatment, especially the hemoperfusion, should be continued or carried out more than one time until the concentration of paraquat in blood plasma decreases to the safe level.