Abstract
Despite their massive application in tea plantation, synthetic pyrethroids had never been detected in tropical soils of tea plantation thus their risk has never been assessed. This research reported the detection of synthetic pyrethroids in tea plantation and assessed their aquatic ecotoxicological risk. A simplified analytical method based on the application of a miniaturized sample, solvent, and efficient ultra-sonic assisted extraction was developed for the determination of pyrethroids in the soil. The method was validated with the result of all parameters (recovery, % relative standard deviations, linearity, limit of detection (LoD), and matrix effect) met the acceptance limits suggested by European Commission guideline, thus deemed acceptable for the assessment of pyrethroids in tropical soil of tea plantation during the wet and dry season. Of the five synthetic pyrethroids, only permethrin was detected in both wet and dry seasons (< LoD – 0.36 μg g− 1), whereas deltamethrin was detected only in wet season (< LoD – 0.12 μg g− 1). Scanning electron microscopy with energy-dispersive X-ray spectrometry and X-ray diffraction revealed that the soil constituted by various soil minerals made permethrin more likely to persist than deltamethrin. Aquatic ecotoxicological risk assessment was performed on the basis of comparison between the maximum equilibrium concentration expected in water (ECEWmax) value and lethal concentration (LC50) of pyrethroids exposure for aquatic species (algae, crustacean, and fish) inhabiting the Upper Citarum River. The ECEWmax value for the present condition was lower than LC50 for all examined species, indicating that the high-level contamination in the future should have posed a high risk for all aquatic species based on their LC50.
Highlights
Over the last four decades, pyrethroids have been commonly used worldwide as pesticides in both domestic and agricultural environments [1]
Numerous studies have reported the presence of synthetic pyrethroids such as bifenthrin, cyfluthrin, permethrin, cypermethrin, deltamethrin, and lambda-cyhalothrin in several rivers in urban and agricultural regions [4,5,6]
The estimated limit of detection (LoD) ranged from 0.006 μg g− 1 for deltamethrin to 0.04 μg g− 1 for permethrin
Summary
Over the last four decades, pyrethroids have been commonly used worldwide as pesticides in both domestic and agricultural environments [1]. Long-term and repeated application of synthetic pyrethroids during agricultural cultivation may contaminate the environment through leaching and runoff. Numerous studies have reported the presence of synthetic pyrethroids such as bifenthrin, cyfluthrin, permethrin, cypermethrin, deltamethrin, and lambda-cyhalothrin in several rivers in urban and agricultural regions [4,5,6]. Soil is a well-known terrestrial reservoir of pesticides and other persistent contaminants. Due to their higher affinity for organic carbon and clay in the soil, pyrethroids persist longer in the soil and sediments (up to 1 yr) despite their shorter half-life than other classes of pesticides [7]. Under anaerobic environments, the mobility and persistence of pyrethroids are lower (with an average half-life of up to 619 d) than those of other types of pesticides [8]
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