Pesticide Residue Levels Research Articles

Zinc Oxide Nanorod-Based Sensor for Precision Detection and Estimation of Residual Pesticides on Tea Leaves.

This study presents the development of a zinc oxide (ZnO) nanorod-based sensor for the detection and quantification of residual pesticides commonly found in tea plantations, with a focus on quinalphos and thiamethoxam. Exploiting the unique electrical characteristics of ZnO nanorods, the sensor exhibits high sensitivity and selectivity in monitoring trace levels of pesticide residues. The detection mechanism relies on measurable changes in electrical resistance when the ZnO nanorod-coated electrodes interact with varying concentrations of the target pesticides. A performance evaluation was carried out using water samples spiked with different pesticide concentrations. The sensor displayed distinct response profiles for each compound: a linear resistance-concentration relationship for quinalphos and a non-linear, saturating trend for thiamethoxam, reflecting their differential interactions with the ZnO surface. Statistical analysis confirmed the sensor's reliability, reproducibility, and consistency across repeated measurements. The rapid response time and ease of fabrication underscore its potential for real-time, on-site pesticide monitoring. This method offers a promising alternative to traditional analytical techniques, enhancing food safety assurance and supporting sustainable agricultural practices through effective environmental surveillance.

Assessment of health risk and burden of disease associated with dietary exposure to pesticide residues through foodstuffs in Iran.

Assessment of health risk and burden of disease associated with dietary exposure to pesticide residues through foodstuffs in Iran.

Comprehensive ecological risk assessment method for multi-pesticide pollution in the Bohai Sea and Yellow Sea, China.

Comprehensive ecological risk assessment method for multi-pesticide pollution in the Bohai Sea and Yellow Sea, China.

Exploring the toxicity of thiamethoxam on aquatic ecosystems: an overarching assessment of biochemical parameters, genotoxicity, fish flesh residues and histological alterations in Nile tilapia

ABSTRACT This study assessed the effect of thiamethoxam on the Nile tilapia (Oreochromis niloticus) under subacute and chronic exposure. The study focused on biochemical markers, genetic damage, pesticide residue levels in fish flesh, and histopathological changes in fish exposed to different concentrations of thiamethoxam (25, 50) for 30 days and (100, 250 mg/L) for 4 days. The study found that prolonged exposure to high doses of thiamethoxam (50 mg/L for 30 days) had significant negative effects on fish health. This exposure led to increased levels of urea and ALT in the blood, indicating potential damage to the kidneys and liver. Additionally, thiamethoxam caused oxidative stress, as evidenced by elevated levels of MDA and upregulated TLR2 gene expression. Thiamethoxam also negatively impacted the fish’s antioxidant defense system. It significantly reduced the expression of key antioxidant genes like ghrelin and catalase, particularly at 250 mg/L for 4 days. The total antioxidant capacity (TAC) and superoxide dismutase (SOD) levels remained relatively stable, except for slight decreases at the highest dose. Thiamethoxam residues were detected in the muscle tissue of fish, with the highest levels found in the 250 mg/L for 4 days. Histological examination revealed severe degenerative changes in the gills and liver tissues of the fish exposed to thiamethoxam, with the severity of the damage increasing with the concentration of the pesticide. In conclusion, cautions must be taken when we use neonicotinoids due to its negative feedback impact on Nile Tilapia fish health and consequently affect humans as a final consumer.

Assessing Pesticide Residue Levels in Sweetpotato Roots and Slips Treated with Fungicides for Management of Southern Blight and Circular Spot Disease Caused by Agroathelia rolfsii.

Since 1971, North Carolina (NC) has been the leading sweetpotato-producing state in the United States and is now producing more than half of the nation's annual output. Because of the high demand for U.S. sweetpotatoes from international markets, NC allocates roughly 40% of its sweetpotatoes for export. However, low fungicide residue limits in primary export markets restrict the ability for NC producers to apply fungicides for disease management during sweetpotato production. Agroathelia rolfsii, the causal agent of southern blight and circular spot, is an important pathogen of sweetpotato. Field experiments were conducted in 2022 and 2023 to quantify the residue amount of various active ingredients and transplant-only versus bedding and transplant applications when managing A. rolfsii in the field. High-performance liquid chromatography analyses of root and vine samples confirmed that none of the tested active ingredients and application timings resulted in residue numbers exceeding the limits of export markets except for roots treated with thiabendazole. Results from this study provide information for development of application practices with acceptable residue levels for export markets while effectively managing diseases caused by A. rolfsii.

LC-MS/MS analysis and validation of pesticides residue in vegetables asserted to be organic

The term pesticides refers to a huge group of compounds (over 1000 substances) that have diverse chemical characters and are found in vegetables in a wide range of concentrations. For this reason, pesticide residue analysis is an important task in order to protect human health. A simple and reproducible analytical method has been developed to simultaneously determination of 35 major pesticides residues in vegetables. Following the analysis of 160 vegetable samples harvested in 2023 and 2024, it was found that around 40% of them contained pesticide residues. In some cases, limits were exceeded, even for organic pesticides, and in other cases, residues of obsolete pesticides were detected. Concluding, the level of pesticide residues in vegetables grown in greenhouses or solariums, even if purchased from local producers, can be harmful.

Single-quad gas chromatography estimation of a few selected pesticides as residues in spices of the National Capital Region of Delhi.

In India, spices play a vital role not only in enhancing the taste and flavor of food but also in offering medicinal properties that help reduce the risk of chronic diseases. However, the extensive and non-judicious use of pesticides in agricultural practices results in the presence of their metabolites in food commodities (fruits, vegetables, spices, cereals) and soil, leading to environmental contamination. Organochlorine (OC) and Synthetic Pyrethroid (SP) pesticides are commonly used for pest control but pose environmental and health risks. These compounds are known for their high toxicity, slow degradation, and bioaccumulation. The present study assessed pesticide residue (OC and SP) levels in 21 spice samples, representing eight condiments-cumin, coriander, chili, fenugreek, black pepper, mustard, ajwain, and dry ginger powder-collected from Delhi-NCR markets, using Gas Chromatography-Mass Spectrometry (GC-MS) and the QuEChERS method. Lambda-cyhalothrin (0.056-0.088mg/kg), pendimethalin (0.059mg/kg), γ-HCH (0.089mg/kg), fenpropathrin (0.062mg/kg), and hexaconazole (0.050mg/kg) were detected in some samples. Specifically, cumin was contaminated with lambda-cyhalothrin and hexaconazole, coriander with cyfluthrin, fenugreek with lambda-cyhalothrin, mustard with pendimethalin, and ajwain with γ-HCH, hexaconazole, and lambda-cyhalothrin. Chili, black pepper, and ginger were free from residues. Average recoveries were 75-90% for ten organochlorine pesticides and 72-85% for seven synthetic pyrethroids, and the RSD% was below 5%. All detected residues were below the maximum residue limits set by FSSAI.

Insights on Degradation, Processing Factors, and Risk Assessment of Pesticide Pymetrozine, Spirotetramat, and Its Four Metabolites on Goji Berry: "Third Pole" Medicine and Food Homologous Crop.

Pesticides are widely used in agriculture, and agricultural commodities are generally consumed as processed foods. How effective these processing procedures are at removing pesticide residues is not well understood. We report initial concentrations of one pesticide that is used extensively on crops of Goji berries, spirotetramat (and its four metabolites: spirotetramat-enol, spirotetramat-enol-glucoside, spirotetramat-monohydroxy, and spirotetramat-keto-hydroxy), and pymetrozine, to be 231.31, 297.42, 229.15, 252.33, 292.73, and 83.18 μg kg-1, respectively. Only 0.18-3.18% of pesticides were eliminated from produce by maceration and washing. Pesticide reduction during processing was 21.23-58.72% (traditional methods), 33.86-73.66% (by cooking samples), and 71.24-90.23% (through vinification), with corresponding processing factors (PFs), a measure of how processing technique affects pesticide residue levels, 0.111-0.771, 0.016-2.33, and 0.008-43.1. For traditional methods, in particular, the PFs of pesticides were 1.77-43.1, suggesting that considerable pesticide enrichment occurred. Combined with the field trial and PF residue data, the acute and chronic dietary risks of pesticides using these processing methods ranged 0.031-1.83 and 0.002-2.51%, respectively. This study provides basic information that can be used to evaluate the potential risks to health of exposure to pesticide residues.

Pesticide residue status and dietary risk assessment of vegetables in Chongqing from 2022 to 2023

To monitor the level of pesticide residues in vegetables in Chongqing and assess the risk of dietary intake. From 2022 to 2023, vegetable samples from 24 districts and counties in Chongqing were collected, and 35 pesticide residues were detected using the relevant standard operating procedures of the NationalFood Safety Risk Monitoring Manual, acute and chronic dietary exposure risk assessment was conducted, and the overall hazard level was assessed using the food safety index. Among 173 vegetable samples, the overall detection rate of pesticide residues in vegetables was 60.7%, and the detection rates were in leafy vegetables(84.29%) > melon or fruit vegetables(57.69%) > Brassica chinensis and cabbage(31.37%), central city(66.67%) > surrounding districts(49.15%). The proportion of samples with two or more pesticide residues was 42.20%. The overall rate of vegetables exceeded the standard 2.31%, and the pesticide residues exceeded the standard for abamectin, phorate sulfone and clothianidin. The result of risk assessment showed that, except for the unevaluated indexes, the acute dietary intake risk of abamectin was at an unacceptable level(the risk of acute dietary intake was 158.14%), and the acute dietary intake risk of the remaining 18 detected pesticide residues was at an acceptable level. The risk of chronic dietary intake and food safety index of all detected pesticide residues were atacceptable levels. The detection rate of pesticide residues in vegetables sold in Chongqing was relatively high, multiple pesticides were detected in the same sample, and some pesticides exceeded the standard, among which abamectin had acutedietary intake risks.

Nationwide prediction of pesticide residual levels in soil: Implications on the resulting risk and prioritization framework.

Nationwide prediction of pesticide residual levels in soil: Implications on the resulting risk and prioritization framework.

Optimizing Unmanned Aerial Vehicle Operational Parameters to Improve Pest Control Efficacy and Decrease Pesticide Dosage in Tea Gardens

Labor shortages in the Chinese tea industry have accelerated the need for crop protection unmanned aerial vehicles (CP-UAVs), which can greatly improve working efficiency. However, CP-UAV operational parameters must be optimized for effective pest control. In this study, the spraying performance of two CP-UAVs (DJI T30 and T40) under different operational parameters were compared in tea gardens. Additionally, the utility of CP-UAVs for controlling tea leafhoppers was investigated. Droplet coverage and size increased as the spray volume increased for both T30 (from 30 L·ha−1 to 90 L·ha−1) and T40 (from 60 L·ha−1 to 150 L·ha−1). Under the same operational parameters, spray deposition at the surface and inner part of the tea canopy was 1.4- and 2.9 times higher, respectively, for T40 than for T30. For T40, droplet penetrability increased significantly following decreases in working height (from 5 to 2 m) and driving speed (from 5 to 3 m·s−1). The spray performance and control effect of T40 were significantly greater under optimal operational parameters (driving speed of 3 m·s−1, working height of 2.5 m, and spray volume of 120 L·ha−1) than under conventional application parameters (driving speed of 5 m·s−1, working height of 4.5 m, and spray volume of 45 L·ha−1). Using T40 under the optimal operational parameters decreased the amount of pesticide required to control tea leafhoppers by 25%, relative to the amount required for traditional knapsack sprayers. Furthermore, pesticide residue levels were similar for T40 and the knapsack sprayer. These findings provide valuable insights into the application of CP-UAVs in tea gardens, which may be important for further developing a modern, intensive, and sustainable tea industry.

ИЗМЕНЕНИЕ СКОРОСТИ РАЗЛОЖЕНИЯ ПЕСТИЦИДОВ ПРИ ИХ СОВМЕСТНОМ ПРИМЕНЕНИИ В ПРОЦЕССЕ ПРОИЗВОДСТВА СЕЛЬСКОХОЗЯЙСТВЕННОЙ ПРОДУКЦИИ

The purpose of research is to study the dynamics of the decomposition of individual active ingredients of pesticides in plant tissues when used in tank mixtures. The field part of the study was carried out on the territory of the Educational, Scientific and Production Center for Horticulture and Vegetable Growing named after V.I. Edelshtein FSBEI HE Russian State Agrarian University – Moscow Timiryazev Agricultural Academy, the laboratory part was carried out at the Educational and Scientific Consulting Center “Agroecology of Pesticides and Agrochemicals” in Moscow during 2020–2021. Research was carried out on crops of spring wheat, oats, spring barley, peas, spring rape, potato plantings, as well as apple tree plantings. Chemical treatments were carried out with insecticides and fungicides approved for use on these crops – Skor, KE; Borey Neo, SK; Tilt, KE; Imidor, VRK; Kumir, SK; Sirocco, KE. The experiment included options with the use of drugs in tank mixtures and options with their separate use. Samples of plant products were taken for further analysis for pesticide content. In laboratory conditions, the level of residual amounts of active drugs in plant samples was analyzed using gas-liquid chromatography and high-performance liquid chromatography methods. The change in the level of pesticide residues in different experimental variants was assessed. The acceleration of the decomposition of the active substance, imidacloprid, on crops of peas, spring wheat, oats, spring barley and spring rape when used together with the drug Tilt, KE was established. Also, the use of the fungicide Skor, KE together with the insecticide Borey Neo, SK (150 g/l imidacloprid + 50 g/l lambda-cyhalothrin) on the apple tree caused a slowdown in the rate of decomposition of the active substances lambda-cyhalothrin and imidacloprid. The use of the copper-containing fungicide Kumir together with the insecticide Borey Neo, SK on the apple tree caused an acceleration of the disintegration of the active substance imidacloprid. The combined use of the fungicide Skor, KE with the insecticides Sirocco, KE and Borey Neo, SK accelerated the decomposition of the active substance difenoconazole.

Optimized methods for the investigation of changes in levels of pesticide residues and their transformation products in iceberg lettuce.

Optimized methods for the investigation of changes in levels of pesticide residues and their transformation products in iceberg lettuce.

MODIFY QUECHER’S EXTRACTION METHOD FOR THE DETERMINATION OF ORGANOPHOSPHATE PESTICIDE RESIDUES IN FISH SAMPLES COLLECTED FROM WURBO AND YELWA LAKES OF BALI, TARABA STATE, NIGERIA

Organophosphate pesticides (OPPs) have been used worldwide, particularly in many African countries especially in Nigeria for the control of pests and weeds for agricultural purposes. Despite the positive outcomes of using pesticides in agriculture, their usage often results in various harmful environmental and health effects on water systems and aquatic organisms. Pesticides, due to their toxicity and impact on biological components, can be termed as biocides—that is, compounds capable of harming all forms of living organisms, including their intended targets. This research was aimed at determining the residual levels of organophosphates pesticides residues in fish species from Wurbo and Yelwa lakes to find out the extent of contamination in the area. The extraction process was performed using QuEChERS method. The extracts were later analyzed for organophosphates pesticide residues using GC-MS. The result showed that the levels of organophosphates pesticides residues in fish samples were higher in Mormyrus rume follow by Clarias gariepinus while the Tilapia zilli recorded low concentration. The total of five organophosphate were recorded. Chlorpyrifos recorded high concentration of 1026.46 ppm in Mormyrus rume from Wurbo lake and 691.92 ppm from Yelwa lake. In Clarias gariepinus, Chlorpyrifos recorded the concentration of 584.45 ppm in Wurbo and 359.41 ppm from Yelwa lake. Ronel recorded levels of 42.53 in Clarias gariepinus and 5.56 ppm in Mormyrus rume from Wurbo. Phosphorodithioic acid recorded the concentration of 8.08 ppm in Clarias gariepinus and 4.84 ppm in Mormyrus rume from Wurbo lake. These values were above the maximum residue limits (MRL) by FAO/WHO, (2009, 2010 & 2021), ranges from 0.001 to 0.5ppm. The results indicate that there is a high level of contamination of these pesticides in fish which may pose a great danger to the environment. Regular monitoring is therefore required to control the levels of pesticide residues in the water bodies.

Quantum Dots‐Engineered Flexible Hydrogel as Plant‐Wearable Sensor for on‐Site Profiling Dynamic Pesticide Degradation

AbstractEngineering wearable devices for in situ and on‐site monitoring of pesticide residues from plants in a non‐destructive manner is of great research value but remains a huge challenge. In this study, a plant‐wearable fluorescence sensor CdTe CDs@PVA@AG, is designed and constructed by embedding CdTe QDs in polyvinyl alcohol (PVA) and agarose (AG)‐co‐assembled double‐network hydrogel to transmit on‐the‐scene pesticides residues messages. Harnessing red emission and stimuli‐responsive performance of CdTe QDs, as well as hydrogel's excellent flexibility, high adhesion, and porous network, CdTe CDs@PVA@AG is endowed with quantitative response to thiram at ≈µm level within 2 min through promoting fluorescence silence in conjunction with the transformation of images into primary colors as digital signals. More interestingly, CdTe CDs@PVA@AG is capable of being tightly pasted onto various crops’ surfaces and then is not only explored to appraise pesticide residue levels but also to profile the dynamic pesticide degradation, in a non‐destructive manner. This work opens up a new avenue to engineer plant‐wearable devices for in situ, on‐site, and non‐destructive capturing of the pesticide residue information from crops, favoring the accurate monitoring of the health status of crops, and rapid and healthy development of smart agriculture.

Investigation of the dissipation kinetics of lufenuron in pepper grown under field conditions

Pepper, Capsicum annuum L. (Solanales: Solanaceae) production is widely cultivated worldwide, with Türkiye ranks third in global pepper production. However, pests in pepper cultivation often necessitate pesticide use, leading to concerns about pesticide residue levels and their potential impact on food safety. This study investigated the dissipation behavior of lufenuron in pepper under field conditions in Tokat, Türkiye in 2022. Liquid chromatography-tandem mass spectrometry coupled with the quick, easy, cheap, effective, rugged, and safe technique was used to analyze residues of lufenuron in pepper. The average recoveries varied from 77% to 97%, with relative standard deviations of 13% for lufenuron. Lufenuron residues administered as recommended dose and double dose degraded in pepper following a first-order kinetic model, with an estimated half-life (t1/2) of 4.33 and 6.42 days in Tokat, 6.80 and 7.45 days in Niksar, respectively. Furthermore, a health risk assessment was conducted, which showed that the chronic risk quotient for lufenuron was much lower than 1. The present results indicated that the health risks posed for consumers by the lufenuron residues were negligible at the recommended dosages.

Detection of glyphosate, glufosinate, and their metabolites in multi-floral honey for food safety

Beehives can accumulate environmental contaminants as bees gather pollen, propolis, and water from their surroundings, contaminating hive products like honey. Moreover, in multifloral environments, bees can interact with plants treated with different pesticides, often causing higher pesticides concentrations in multi-floral honey than in mono-floral varieties. Glyphosate and glufosinate are both widely used herbicides. Glyphosate accounted for one-third of herbicide sales in Europe in 2017 and continues to raise health concerns, including its potential carcinogenicity. While the European Commission extended glyphosate’s authorisation for another 10 years in 2023, concerns remain about its impact on biodiversity and human health. This study aimed to monitor the presence of glyphosate, glufosinate, and their metabolites in 100 samples of multifloral honey representing Italian production by analysis using IC-HRMS. Results indicated that 12% of honey samples contained glyphosate residues ranging from > LOQ to 45 ng g−1, with the highest concentrations detected in the Puglia region. No sample exceeded the maximum residue levels set by EU regulations. Glufosinate and its metabolites were not detected in any samples. These findings underscore the need for continued monitoring of pesticide residues in honey, particularly given the potential ‘cocktail effect’ of multiple contaminants and their combined toxicity. This study highlights the importance of safeguarding consumer health, especially in vulnerable populations, by addressing gaps in data on pesticide residue levels.

Groundwater Pollution in Koudougou, Burkina Faso: Chemical and Microbiological Assessment

Continued population growth in African cities has led to an increase in the demand for agricultural produce, with intensive use of inputs. The practice of market gardening in the vicinity of water bodies has an impact on groundwater quality. To make up for the lack of water, some people in the town of Koudougou resort to wells and boreholes. This study assessed the chemical and microbiological pollution of groundwater in the town of Koudougou, Burkina Faso. To this end, 40 water samples were taken from wells and boreholes near watercourses and in market garden production areas. Analyses were carried out using microwave plasma atomic emission spectrometry (MP-AES) and molecular absorption spectrophotometry. Principal component analysis was performed using XLSTAT software, and hydrochemical facies analysis was performed using Diagram software from the Laboratoire d'Hydrogéologie, Université d'Avignon. The extraction of pesticides from the water was adapted to the QuEchERS method proposed by Standard NF EN 15662 of 01/2009. Bacteria were also detected by filtration on cellulose membranes. The results of principal component analysis of the water samples revealed strong correlations between Ca2+ and Mg2+ (0.98), Al3+ and Fe2+ (0.96), Cl- and Na+ (0.93), NO3- (0.80). Thus, the origin of the chemical elements could be explained by direct infiltration of surface water and the influence of anthropogenic activities. Analysis of the hydrochemical facies reveals anthropogenic pollution. In addition, the high Al3+ content (0.31 mg/L) in some wells exceeds the WHO threshold value (0.2 mg/L), and is partly linked to rock weathering. In addition, pesticide residue levels have been found to exceed standards. The water is contaminated with faecal matter, with total coliform levels reaching 800 CFU/100 mL. All in all, well water as a whole and 80% of borehole water were found to be unfit for human consumption.

Effect of Stir-Frying, Boiling, and Baking on Hexaconazole Residue Levels in Welsh Onion (Allium fistulosum L.).

Hexaconazole, a triazole insecticide, is widely used to control rust disease in Welsh onions. Residue levels of pesticides vary based on the cooking methods. Although studies on hexaconazole residue have involved vegetables such as cabbage, research on Welsh onion is limited. This study investigated the effect of different cooking methods on hexaconazole residues. Welsh onion was processed by common cooking methods such as stir-frying, boiling, and baking, and analyzed for pesticide residues using liquid chromatography with tandem mass spectrometry. The results showed that the removal rates of pesticides after cooking were 40.0-62.9% for stir-frying, 80.0-91.4% for boiling, and 51.4-77.1% for baking. Regardless of cutting thickness (0.8 cm or 5 cm), the reduction rate of pesticide residues increased with time during boiling. Increased reduction rates were also observed with increased time during baking. As stir-frying time increased, the residue amount increased due to water loss. However, the absolute amount of the pesticide decreased with increasing time. Therefore, the residue amount of hexaconazole in Welsh onion was reduced by various general cooking processes. These findings can provide a valuable foundation for research on Welsh onion processing, address consumer concerns about pesticide residues, and provide baseline data for risk assessments.

Pesticide Residue Levels in Water and Sediment from River Thiba, Kirinyaga County, Kenya.

The study assessed the physicochemical parameters and pesticides residue levels in water and sediment samples from Thiba River Catchment area, Mwea Irrigation Scheme, Kirinyaga County, Kenya. The samples were collected from six selected sampling sites in February and May 2021 representing dry and wet seasons respectively, by the meteorological department and based on the human activities and crops grown. The physicochemical parameters determined were pH, total dissolved solids (TDS), total suspended solids (TSS) and electrical conductivity (EC) in water samples and pH and total organic carbon content in the sediment samples. The pH of water samples ranged from 6.12 ± 0.12- 6.91± 0.17, as Total dissolved solids were at 10.03 ± 2.04 mg/L – 100.04 ± 1.10 mg/L while Total Suspendeed Solid values were 103.01 ±3.51mg/L -316.01 ± 6.81 mg/L, and Eelectrical Conductivity was in the range of 30.01± 1.21 µscm-1–200.13 ± 2.01 µscm-1. In the sediment samples, the pH ranged from 5.42 ± 0.12 – 7.52 ± 0.11 and the organic matter content ranged from 27.72± 0.62 – 49.07± 0.78. The farmers applied 12 different pesticides, under different trade names and active ingredient. Chlorpyrifos was the highest used pesticide by 72 % of the farmers followed by Lambda-cyhalothrin at 64 %. The pesticides obtained from the samples were Metalaxyl, chlorpyrifos, and lambda cyhalothrin. In the water samples, chlorpyrifos residue levels ranged from 3.60±0.92 µg/L – 88.24 ±65.97 µg/L, with Metalaxyl from < 0.05 µg/L – 4.24 ± 1.75 µg/L, while Lambda cyhalothrin were in the range of < 0.005 – 3.75±0.72 µg/l in both the dry and wet seasons. Generally, the Chlorpyrifos residue levels were higher in wet season than the dry season while Metalaxyl and Lambda-cyhalothrin values were higher in the dry than wet season. Metalaxyl residue levels in sediment samples in the dry ranged from < 0.05 µg/kg – 1.27±0.90 µg/kg for wet seasons, while Chlorpyrifos ranged from 4.77±17 µg/kg – 47.78±7.12 µg/kg and Lambda-cyhalothrin values were from < 0.005-0.67±0.18 µg/kg in both the dry and wet seasons respectively. Chlorpyrifos pesticide residue levels were the highest in the sample matrices, due to its widespread use to control ticks and fleas from the livestock in the study area. For the chlorpyrifos pesticide levels, all the sites in the dry season were within the acceptable limits of 30 µg/L except site 2. However, the levels were higher than the limit except in sites 1 and 3. For the Metalaxyl and lambda-cyhalothrin pesticides, all the sites had levels that were below the set limits for drinking water by WHO of 10 µg/L.