The Exposure Risk To Pesticide Handlers Spraying In Corn Field

Pesticide occupational exposure risk assessment plays a pivotal role in the protectionpesticide applicators. Researches abroad have sdudied a lot and established their ownexposure model. Our study on occupational exposure risk assessment is just in thepreliminary period, lacking sufficient data. It is difficult to establish our own exposuremodel. Therefore, this research studied the exposure dosage to the skin of operators in thecornfield using the whole body dosimetry technique. The detection method for the contentof chlorpyrifos in the sampling media was established. The date of pesticide exposure toapplicators in the cornfield at different time was collected when the hight of the corndiffered. Then the pesticide exposure dosage and the distribution on the body to applicatorswas also studied. The main contents and results were as follows:1. The chlorpyrifos exposure detection method was established and checked. GC-FPDwas used to detect the content of chlorpyrifos in the sampling media of operators. Thestandard curve of chlorpyrifos was y=20.14x (R2=1), which has a good linear correlation inthe range of0.01-100.00μg/mL. The LOD and LOQ were0.01μg/mL and0.05μg/mLrespectively. The recovery rates of the protective clothing were83.52%-99.30%, and theaverage recovery rates were all more than89.25%, whose RSD was less than5.34%. Therecovery rates of the gloves was94.29%-117.81%, with the average recovery rates all morethan102.91%, and the RSD was less than7.09%; The recovery rates of the acticarbon was73.62%-96.74%, whose average recovery rates were all more than77.71%, with the RSDless than10.20%. The recovery and RSD of the three kinds of sampling media meets therequirements of the test.2. Stability of Chlorpyrifos in the sampling medium was studied, which showed thattransporting the collected sample back to the lab after the end of the field trials would notaffect the experimental results. Chlorpyrifos in the sampling medium would keep stably nomatter whether stored at room temperature (25℃) for48hours, stored for7days at4℃orstored for180days in the freezer (-18℃). All the store conditions above would not affectthe experimental results. Therefore, the samples could be collected in the field andtransported to the laboratory,then placed in freezing conditions for180days, stably at thesame time. The pretreatment samples could be stored in the refrigerator at4℃temporarily,but they must be measured within7days. The processing samples would be measuredwithin48hours at room temperature. All the above operations had no effect on the results. 3The pesticide exposure dosage and the distribution on the body to applicators wasstudied at different time using the whole body dosimetry technique when the hight of thecorn differed. The results showed that the average exposure of inner and outer protectiveclothing was4.233μg/g and26.867μg/g respectively when the height of corn was58.8cm.The major exposure parts of the outer protective clothing were concentrated in the left andthe right leg, reaching102.236μg/g and97.361μg/g respectively. The major exposure partsof the inner protective clothing were concentrated in the legs and socks. Both exposure partsof the protective clothing were concentrated in the lower part of the body. The averageexposure of inner and outer protective clothing was23.387μg/g and102.991μg/grespectively when the height of the corn was105.9cm. The largest exposure parts of theouter protective clothing were the legs, the lower arms and gloves also included. The largestexposure parts of the inner protective clothing were the legs, socks, thighs and also gloves.The average exposure of inner and outer protective clothing was15.097μg/g and116.680μg/g when the height of the corn was173.6cm. The major exposure parts of the outerprotective clothing were concentrated in the higher part of the body, such as lower arm,upper arms and gloves. The major exposure parts of the inner protective clothing were alsoconcentrated in the higher part of the body, such as lower arm, gloves and thighs.The major exposure parts of the inner and the outer protective clothing changed from thelower parts of the body to the upper parts with the corn height varied from58.8cm to173.6cm. The exposure of the right part of the body was more than the left part at the hight of58.8cm. There was no difference between the exposure of the two sides of the body whenthe hight of the corn was105.9cm and173.6cm.4. Operators should pay attention to their self-protection when spraying pesticide in thecornfield. They should pay attention to the lower and the right part of the body when thecorn was low. With the growth of the corn, the protective parts would be both sides of theupper body. Operators should pay attention to avoid direct contact with the droplets on theblades when spraying the pesticide solution. The back was the direct area contact with thespray, and the opening of the spray was close to the human head. We should avoid thesplashing of the pesticide solution. In addition to develop scientific the spraying habits,spraying the best weather is nice.