Dermal exposure of applicators to chlorpyrifos on rice farms in Ghana.

TLDR: The findings of the present study suggest that protecting the hands and the lower anatomical regions with appropriate PPE may significantly reduce exposure among applicators.

About: This article is published in Chemosphere.The article was published on 2017-07-01 and is currently open access. It has received 33 citations till now.

Figures

Figure 1: Tyvek Under-wear Garment, Hand Gloves and Socks Sectioned into Nine Anatomical Regions.

Table 1: Observed Field Factors during Spraying of Rice Crops with Chlorpyrifos by Applicators in Ghana

Table 2: Pattern of Chlorpyrifos Deposition on the Anatomical Regions of Individual Applicators on Rice Farms in Ghana.

Table 3: Factors Associated with Total Dermal Exposure (TDE) of Chlorpyrifos among Applicators on Rice Farms in Ghana (n = 24).

Figure 4: Proportion of Exposure (% of TDE) of the Upper and Lower Anatomical Regions of Applicators on Rice Farms in Ghana.

Figure 3: General Patterns of Chlorpyrifos Deposition on the Anatomical Regions of Applicators on Rice Farms in Ghana.

Frequently asked questions

Q1. What contributions have the authors mentioned in the paper "Dermal exposure of applicators to chlorpyrifos on rice farms in ghana" ?

This study used the more accurate whole-body dosimetry technique to evaluate dermal exposure to chlorpyrifos among applicators on rice farms in Ghana. The pesticide UE data of the present study can be used to estimate the levels of dermal exposure under similar pesticide 2 use scenarios among applicators. The findings of the present study suggest that protecting the hands and the lower anatomical regions with appropriate PPE may significantly reduce exposure among applicators. 

Q2. What type of sprayers were used by the applicators in the present study?

Whereas hand-pressurized knapsack sprayers were used by applicators in the present study, the applicators in the study by An et al. (2015) used powered knapsack sprayers. 

Q3. What was the predominant use of pesticides?

The use of pesticides to control farm insect pests was predominant, with chlorpyrifos being one of the commonly used insecticides. 

Q4. How many mL of insecticide were used during one spray event?

The duration and insecticide quantity during one spray event ranged from 21 to 110 minutes (mean, 57 minutes) and 100 to 325 mL (mean, 182 mL), respectively. 

Q5. What was the highest level of contamination of the hands?

hand contamination represented between 85% - 99% of total dermal exposure among agricultural subcontractors who did not use hand gloves (Vitali et al., 2009). 

Q6. What is the UE value of the pesticides used in the present study?

The UE value (0.03%) obtained in the present study among the median exposed group (CP50) of the applicators was thrice the dermal UE value of 0.01% (when converted to metric mass units from the stated 58,400µg /pound AI) for a similar pesticide use scenario of the USEPA’s unit exposure surrogate reference table (USEPA, 2016). 

Q7. What was the percentage of exposure on the lower anatomical region of the body?

Tuomainen et al.(2002) also found among applicators who sprayed rose plants that exposure on the lower anatomical region constituted about 78% of total exposure. 

Q8. What were the average skin surface areas of the anatomical regions determined and applied?

The average skin surface areas of the anatomical regions determined and applied were as follows: head (1,200 cm2), front abdomen (3,950 cm2), back abdomen (3,950 cm2), upper arm (1,700 cm2), lower arm (1,200 cm2), hands (680 cm2), upper legs (2,300 cm2), lower legs (2,000 cm2), and feet (750 cm2). 

Q9. What was the percentage of exposure on the legs in the study?

The study reported by Cao et al. (2015) revealed that the level of exposure on the lower anatomical region (upper and lower legs) was about 76 - 79% of total exposure, compared to 9 – 10% for the upper anatomical region (head, chest, back, and arm). 

Q10. What is the importance of dermal exposure?

Studies on dermal pesticide exposure are needed to enhance understanding of the contribution of the dermal route to total exposure, the patterns of dermal exposure, as well as help to identify effective exposure prevention and control strategies (Leckie and James, 1998; Marquart et al., 2001). 

Q11. What are the main reasons for not carrying out pesticide exposure and risk assessment studies?

In many developing countries such as Ghana, pesticide exposure and risk assessment studies are usually not carried out as part of the processes for registering new pesticides for a number of reasons including financial and logistical challenges. 

Q12. What is the average CPD plot of the environmental pollutant?

The linear part of the CPD plots of environmental pollutant levels, when normal distribution occurs, is usually determined to lie between 20% or below (lower bound) and 80% or above (upper bound) of the CPD (Edokpolo et al., 2015; Sadler et al., 2016).