Occupational exposure to currently used pesticides (CUPs) in Lahore Pakistan: Environmental load, exposure markers, risk diagnosis and evaluation of model based ecotoxicity

Abstract

Background: After ban on organochlorine pesticides (OCPs), currently used pesticides (CUPs), formulation and application are on rise in mega cities of Pakistan. Occupational health safety and environment issues related with CUP’s are increasing in agriculture and industrial sector. Exposure to CUP’s can produce a variety of biochemical alterations in the form of endocrine disruption, oxidative stress and BuChE inhibition which serve as potential biomarkers of exposure and effect. Having least technological aids, the agriculture and industry are dependent on manual handling. Such handling to chemicals from the agrochemicals is not only a cause of occupational health hazards but also leads to growing worker safety issues. In addition, studies highlighting the pesticide related ecological impacts and model based best pesticide management approaches are lacking in Pakistan. Objectives & design: Concentration profile of currently used pesticide’s such as organophosphates, pyrethroids and carbamates were analyzed in soil, dust, water and air of mega city Lahore Pakistan. The effect of currently used pesticides was investigated on blood and urine parameters of subjects: farmer, factory worker, and vendor/shopkeeper, urban resident, rural resident and controlled subjects with presumably different levels of exposure. The urinary metabolites (TCPY and IMPY) were quantified as biomarkers of exposure to chlorpyrifos and diazinon in relation with biomarkers of effect including BuChE, LH, FSH, testosterone and oxidative stress. Several variables such as height, weight, working hours, income, and work experience were investigated for their contribution towards variation in biomarkers of exposure and effect. Special focus was paid on linking biochemical markers in exposed subjects with pesticide concentration in environmental matrices. Human health risk was estimated via dust, soil, air and water contaminated with pesticides for aforementioned human population. Occupational issues related to formulation and pesticide application were studied based on interviews data. The ecological impact of selected pesticides was studied and emphasized using model based approach. Results: Among the investigated analytes, the chlorpyrifos was the predominant compound in dust and soil with concentration ranging from 4-15.1 ug/g and 1.14 – 7.92 mg/kg respectively. In ground water, diazinon was detected with higher concentration ranging from 0.54– 1.92 ug/l from agricultural zone. However, in outdoor air deltamethrine was detected with higher concentration ranging from 151– 251 ng/m3 from agricultural zone. Post hoc LSD test described significant variations (>0.05) were observed among the CUPs concentration collated from different landuse based sites. Based on estimated daily intake and HQ values, a relatively higher risk via chlorpyrifos and diazinon dermal and inhalation pathways were determined in exposed population. The mean SOD value was high among the farmer (3048 U/g Hb) followed by factory worker (1677.6U/g Hb). The urinary biomarkers – TCPY and IMPY- were found higher in exposed subjects as compared to control. For hormonal investigation, testosterone was found in higher concentration in factory worker than control (12.63 ng/ml vs 4.61 ng/ml respectively). A decreased BuChE activity was noticed in occupational group and significant differences ( > 0.05) were observed in control verses exposed subjects. The PCA analysis, correlation and regression supported the impact of pesticides present in environment (air, soil, dust and water) on exposure biomarkers and male reproductive hormones. Multiple regression analysis revealed that height and weight are important variable that can control the activity of studied biomarkers. Several factors were identified using checklist to determine the status of occupational hazards (chemical, fire, ergonomic, injuries and accidents) in pesticide factories. Results reveal that most of the pesticide factories (99%) emitted chemicals cling with dust, fume, mist or vapors. To cope with that problem 75% of them provided with local exhaust ventilation system. Interview of farmers exhibited the hazards faced by farmer during storage handling and application of pesticides. Overuse of pesticides was documented for farmers with low literacy rate. 95% of farm workers used to work in fields without wearing any PPEs during pesticide application on agricultural land. Most of the Farmers (45%) store pesticides anywhere in their own houses. Only 12% of the farmers store them in specific store rooms as recommended by department of agriculture Punjab. Environment impact quotient (EIQ) field use rating values of selected pesticides in Lahore rural region were predicted using model (EIQ field-use). The ranking standards are in the series of 20–152.25 being lowest for pirimicarb and highest for chlorpyrifos. Average EIQ standards for farmstead personnel, users and environ constituent be situated 13.50, 4.42 and 80.09 correspondingly. Current findings directs that the farmhouse operative module is 3 times larger than the end user module, and environ dynamics are esteemed 6 times bigger than the farmstead workforces section and 18 times advanced than the end user module, enlightening likelihood of upper influence on the environ module. An impact area analysis for each compound was completed individually using ipm-PRIME model. At hand are huge influence regions greater than 50 hectares, nearby 12% of the regions under agronomy in our investigation, contained by entirely the discrete hazard directories that we accomplished, but the pesticide composite accountable for risk diverse in every index. The uppermost influence regions inside every index were characterized by chlorpyrifos for avian acute and avian reproduction; diazinon for fish chronic; pirimicarb for earthworm, deltamethrine for small mammal acute. Conclusions: CUP’s level in soil, dust air and water collected from industrial agriculture, rural and urban residential zones were positively associated with pesticide specific biomarkers of exposure and effect investigated in industrial worker, farmer, rural and urban resident. Occupational situation of factory worker and farmer is critical in pesticide formulation and application sector. Results accentuate the significance of continuing work place preventive activity, and model based best pesticide choice for applicators which is mainly the responsibility of state, but which also encompasses government organizations, trade unions, employees, and professional connotations