Harnessing the Carrier Solvent Complexity of Crop Biostimulant Liquid Formulations Using Locally Available Transesterified Waste Cooking Oil: Economic Recycling, Solvent Performance, and Bioefficacy Evaluation.

Locally sourced waste cooking oil (WCO) was successfully base-catalyzed and transesterified with methanol into biodiesel to produce biostimulant (nitrobenzene) formulations and replace high-risk carrier solvents. Ideal synthesis conditions were composed of 1% NaOH, MeOH/oil molar ratio (6:1), reaction temperature (65 °C), a 3 h mixing rate, and 97-98% yields. Gas chromatography-mass spectrometry (GC-MS) analysis identified five fatty acid methyl esters (FAMEs) including palmitic, linoleic, oleic, stearic, and eicosenoic acids with high solubilization and olfactory characteristics. Using anionic and nonionic emulsifiers in conjunction with recycled biodiesel, a stable emulsifiable concentrate (NB 35% EC) was created with greater storage stability, wettability, and spreading capabilities than those of organic solvent-based ones. The highest counts of fruits per plant (35.80), flowers per plant (60.00), yield per plant (3.56 kg), and yield per hectare (143.7 quintals) were recorded in treatments with 4 mL/L biodiesel-based EC in field bioassays. In addition to having superior biosafety, FAME-based EC exhibits minimal phytotoxicity and is less harmful to aquatic creatures. It was discovered that the average cost-effectiveness was 5.49 times less expensive than solvent-based EC. In order to utilize waste oils as a locally obtained, sustainable alternative solvent with a wide solubilization range, low ecotax profile, circular economy, and high renewable carbon index, this integrative technique was expanded.

Selection of green carrier solvent for the effective creation of bio-inspired liquid formulation and anti-fungal potency evaluation.

Existing pesticide formulation solvents generate volatile organic compounds (VOCs), are combustible, and are classed as hazardous air pollutants (HAPs), meaning they are detrimental to users and phytotoxic to crops. Green solvents are required in formulations due to regulations, health, and environmental concerns. In emulsifiable concentration (EC) formulations, the "green chemistry" movement has led to the use of less harmful solvents. After a detailed and comparative fungal growth inhibition assessment, the least harmful carrier solvent among four regularly used organic solvents [dimethyl sulfoxide (DMSO), dimethylformamide (DMF), aromatic hydrocarbon (C9), and methyl oleate] was chosen in this study. We employed methyl oleate (cis-9-Octadecenoic acid methyl ester) as a bio-based green reserver (60%) to create effective bioinspired EC formulations (30%) of Pongamia pinnata L extract utilising emulsifier blends (10 percent) based on the known toxicity order (DMF > DMSO > C9 > methyl oleate). EC1 outperformed the other thirteen formulations (EC1-EC13) in terms of emulsion stability, cold test, accelerated storage stability, flash point, and other metrics, proving its suitability for commercial production. Using four therapeutically appropriate concentrations of agricultural usage, in-vitro fungicidal effects against Alternaria solani and Phytophthora spp. were examined.A. solani (EC50 = 0.08 percent) showed the greatest growth suppression (87.4 percent) at the maximum dosage (1 percent), followed by Phytophthora sp. (71.1 percent) (EC50 = 0.49 percent). The study proved its utility in the production of environmentally acceptable green solvent-based herbal formulations as a long-term crop protection alternative to harmful chemical pesticides.

Integrated biomarker approach strongly explaining in vivo sub-lethal acute toxicity of butachlor on Labeo rohita.

Butachlor herbicide belongs to the family of chloroacetanilide group, widely used for control of grass and broadleaf weeds in paddy fields however, its repeated application may result in aquatic pollution. Butachlor residue has been detected in aquatic environments, which may produce toxic effects on non-target organisms including fish. Keeping this in mind, the present study was designed to estimate the LC50 of butachlor (Shaktiman®), and to evaluate the sub-lethal toxicity at two concentrations (12.42 µg L-1 and 62.10 µg L-1) in Labeo rohita for a period of 24, 48, and 72 h. Fish exposed to butachlor reduced the counts of red blood cells (RBC), haemoglobin (HGB), hematocrit (HCT), and white blood cells (WBC). A significant (p < 0.05) increase in the antioxidant enzyme (superoxide dismutase-SOD, glutathione-s-transferase-GST), and hepatic enzyme (glutamate-oxaloacetate transaminase-GOT, glutamate-pyruvate transaminase-GPT) were noticed in butachlor exposed fish. Heat shock protein 70 (HSP70) and HSP90 in gill; cortisol, protein, albumin, globulin, and triglyceride in serum were increased upon exposure of butachlor. On the contrary, complement 3 (C3) and immunoglobulin (IgM) in serum was found to be decreased compared to control fish. The findings thus suggest that the fish upon exposure to butachlor disrupts the biomarkers which ultimately leads to growth retardation in fish.

Assessment of the effect of sub-lethal acute toxicity of Emamectin benzoate in Labeo rohita using multiple biomarker approach.

Emamectin benzoate (EMB) is a potent neurotoxin agent, widely used for ectoparasites control in aquaculture, but their detailed toxicological implications in Labeo rohita are unknown. Thus, this study was conceptualized to determine the LC50 and to investigate the effects of two sub-lethal concentrations 1/50th of 96 h LC50 (1.82 µgL-1) and 1/10thof 96 h LC50 (9.1 µgL-1) on hemato-immunological and biochemical responses in L. rohita (mean weight 25.54 ± 2.3 g and length 10.35 ± 2.4 cm) for a period of 24 h, 48 h, and 72 h. LC50 of EMB were 163 µgL-1, 112 µgL-1, 99 µgL-1 and 91 µgL-1 at 24 h, 48 h, 72 h, and 96 h respectively. The safe limit at 96 h LC50 of EMB was 2.30 µgL-1. In EMB treated fish, red blood cells, white blood cells, hemoglobin, and hematocrit counts were reduced (p < 0.05) significantly. Superoxide dismutase (SOD) activity in the liver and kidney declined (p < 0.05) at 72 h while in gill and muscle the activity increased significantly. Glutathione-s-transferase (GST) activity in the liver, gill, and kidney increased (p < 0.05) while muscle decreased significantly. Catalase (CAT) activity in liver, gill, and muscle decreased while in kidney increases. Glutamic-oxaloacetic acid transaminase (GOT) activity and Glutamate pyruvate transaminase (GPT) activity were increased in liver, kidney, and muscle tissue. The change in serum triglycerides, serum protein level was noticed. The level of cortisol, heat shock protein 70 (HSP70), and HSP90 increased (p < 0.05) while the immunological responses like immunoglobulin M (IgM) and complement 3(C3) activity decreased (p < 0.05) in EMB exposed fish. Thus, EMB exposure at two sub-lethal concentrations in L. rohita induces several hemato-immuno, and biochemical alterations in blood, serum, and different organs. The overall result of the present study indicated that EMB is toxic to fish even for a short-term exposure and low doses, and therefore utmost caution should be taken to prevent their drainage into water bodies.

Ecological safety with multifunctional applications of biogenic mono and bimetallic (Au-Ag) alloy nanoparticles.

Recently, the design and biosynthesis of metallic nanoparticles (NPs) have drawn immense interest, but their very specific function and secondary toxic effects are major concern towards commercial application of NPs. That's why environment-friendly (nontoxic) NPs having multiple functions are extremely important. Herein, we report the mechanism of biosynthesis of mono and bimetallic (Au-Ag) alloy NPs and study their multifunctional (antioxidant, antifungal and catalytic) activity and ecotoxicological property. AgNPs exhibit phytotoxicity (at 100 µg/ml) on morphological characteristics of Lentil (during germination), while alloy and AuNPs are non-toxic (up to 100 µg/ml). In-vitro antioxidant response using DPPH methods reveals that alloy NPs (IC50 = 55.8 µg/ml) possesses better antioxidant activity compared to the monometallic NPs (IC50 = 73.6-82.6 µg/ml). In addition, alloy NPs displayed appreciable antifungal efficacy against a plant pathogenic fungus Gloeosporium musarum by structural damage to hyphae and conidia of the fungus. The catalytic performance of NPs for degradation of chlorpyriphos (CP) pesticide reveals that alloy NPs is more efficient in terms of rate constant (k = 0.405 d-1) and half-life (T50 = 1.71 d) compared to the monometallic counterparts (k = 0.115-0.178 d-1; T50 = 3.89-6.04 d). Degradation products of CP (3,5,6-trichloropyridinol and diethyl thiophosphate) are confirmed using mass spectrometry and based on that a degradation pathway has been suggested. Thus, these sustainable and ecological safe biogenic (Au-Ag) alloy NPs promise multiple applications as an antioxidant in the pharmaceutical sector, as a fungicide for disease control in agriculture, as a catalyst for remediation of toxic pollutants and in other pertinent areas.

Dissipation behaviour and risk assessment of fipronil and its metabolites in paddy ecosystem using GC-ECD and confirmation by GC-MS/MS.

Fipronil -a broad spectrum phenylpyrazole insecticide has high level of toxicity towards environment. Therefore, an easy and reliable analytical method was developed for residue estimation of fipronil to ensure food and environmental safety. A modified QuEChERS technique was followed for estimation of fipronil (5% SC) in paddy ecosystem using GC-ECD and confirmation by GC-MS/MS. The initial residues (0.168-0.794 µg g-1) of total fipronil i.e., sum of fipronil and its metabolites (viz., desulfinyl and sulfone) in leaf and soil were dissipated following first order kinetics. About 92-96% of fipronil residues were degraded after 15 days with half-life of 3.4-4.1 days and pre-harvest interval of 19.4-25.7 days in plant. Residues were below level of quantification (<0.005 µg g-1) in plant and soil at harvest. The fipronil residues in rice grain present low dietary risk (RQd < 1) to human health. However, high risk (RQd > 1) was predicted for cattle health due to fipronil residues in paddy leaf up to 10 days. The residual level in soil was also at highrisk (RQs > 1) for soil ecological health.

Encapsulation, release and insecticidal activity of Pongamia pinnata (L.) seed oil.

Pongamia pinnata (L.) seed oil is effective for its insecticidal and larvicidal activities. However, its low aqueous solubility, high photosensitivity, and high volatility restrict its application for the control of agricultural pests. Encapsulation can be an effective technique to overcome such hindrances. Therefore, P. pinnata oil (PO) was extracted from its seeds and analyzed for karanjin content (3.18%) by GC-MS/MS as the marker compound. Micro-encapsulation (MC) of PO was prepared by interfacial polymerization between isocyanates and polyamine and tested for insecticidal and larvicidal activities. Bioassay of the developed formulations was tested in-vitro against 2nd instar larvae of Bombyx mori (Bivoltine hybrid) and in-vivo insecticidal bio-efficacy was tested against aubergine aphid (Aphis gossypii G.) and whitefly (Bemisia tabaci G.). Various properties of micro-capsules viz., stability, size, oil content and release kinetics were examined. Average diameter of capsules (1 µm) with Zeta potential (-16 mV) was indicated by the Dynamic Light Scattering (DLS) instrument. Existence of PO in the microcapsules was confirmed by an optical microscopic study. Spectroscopic analysis revealed 87.4% of PO was encapsulated in polyurea shell. The shelf-life (T 10 ), half-life (T 50 ), and expiry-life (T 90 ) of polyurea coated capsules were 11.4, 75.3 and 250.0 h, respectively. Polyurea coated PO capsule formulation showed evidence of in-vitro toxicity against 2nd instar larvae of B. mori (LC 50 = 1.1%; LC 90 = 5.9%). The PO formulation also exhibited 67.0-71.8% and 62.4-74.8% control of aphid and whitefly population in aubergine at 4.0% dose following 7-14 days after application. The study unveiled its significance in developing controlled release herbal formulations of P. pinnata as an alternative to harmful conventional synthetic insecticides for crop protection.

Author Correction: Process optimization for biosynthesis of mono and bimetallic alloy nanoparticle catalysts for degradation of dyes in individual and ternary mixture.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Process optimization for biosynthesis of mono and bimetallic alloy nanoparticle catalysts for degradation of dyes in individual and ternary mixture.

Nanoparticle (NP) catalysts are widely used for removal of dyes for single use, but there is an acute need for developing catalysts with high efficiency and reusability for mixed dyes. Here we first optimized the process (reactant proportion, temperature, time, and pH) for biosynthesis of monometallic Ag, Au and bimetallic Au-Ag alloy NP catalysts using Polyalthia longifolia leaf extract. The biosynthesized NP catalysts were characterized by UV-vis, DLS, Zeta potential, TEM and EDX study while the probable biomolecules responsible for biosynthesis were identified by FTIR and GC-MS/MS analysis. The NPs are found to be mostly spherical in shape (size 5-20 nm) with prolonged stability. We evaluated their chemo-catalytic performance through degradation of dyes (methyl orange, methyl violet, methylene blue) in individual and ternary mixture in presence of NaBH4. The degradation percentage (80.06-96.59% within 5 min), degradation kinetics (k = 0.361-1.518 min-1), half-life (T50 = 0.457-1.920 min) and 80% degradation (T80 = 1.060-4.458 min) of dyes indicated highest catalytic activity of alloy in ternary mixture. Here we report a unique vacuum filtration system using alloy coated beads with excellent catalytic activity which could be reused thrice for removal of hazardous ternary mixed dyes with great promise for environmental remediation.

Simultaneous determination and risk assessment of fipronil and its metabolites in sugarcane, using GC-ECD and confirmation by GC-MS/MS.

A sensitive gas chromatographic method using a modified QuEChERS technique is reported for simultaneous determination, dissipation and risk assessment of fipronil and its metabolites in sugarcane and soil. Recoveries were 80.7-98.5% with precision within 1.4-16.5% estimated at the limits of detection (LOD) 0.0015-0.002 µg g-1 and limits of quantification (LOQ) 0.005 µg g-1. Fipronil dissipated with half-life (T1/2) of 2.8-4.3 days while for total fipronil it was 3.7-6.0 days following application of fipronil (5% SC) in sugarcane fields at recommended (100 g a.i. ha-1) and double the recommended (200 g a.i. ha-1) doses. Estimated pre-harvest intervals (PHI) for fipronil were 20.3-27.0 days in sugarcane plants, and for total fipronil the corresponding values were 28.2-37.8 days. No dietary risk was observed due to fipronil (RQd < 1) 5 days after application. Potential risk exists towards algae and soil macro-organism (RQs > 1), but for earthworms it was safe (RQs < 1).

GC-MS/MS determination and ecological risk assessment of pesticides in aquatic system: A case study in Hooghly River basin in West Bengal, India.

A liquid-liquid extraction (LLE) for water and modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for sediment combined with gas chromatography-tandem mass spectrometry (GC-MS/MS) detection in multiple reaction monitoring (MRM) mode was standardized for determination of 31 pesticides. Performance characteristics for the selected pesticides were acceptable according to European Commission's (EC) guidelines for method validation (recovery 70-120%, RSD <20% and R2 value ≥ 0.99). River, pond and tubewell water and river sediment samples (64 nos.) were collected from Hooghly River basin in West Bengal, India during 2014-2016. About 42% of the samples showed the presence of 19 pesticides with the highest loading of total pesticides (T-pesticides) in river water (3.01 ng mL-1) followed by sediment (1.25 ng g-1), pond (0.40 ng mL-1) and tubewell (0.02 ng mL-1) water. The non-agricultural OC (organochlorine) insecticides were detected in all river water and sediment samples mainly due to HCHs (hexachlorocyclohexane) from old source and fresh use of DDTs (dichlorodiphenyltrichloroethane) in local areas. No OC insecticides were detected in pond and tubewell water. Maximum residues of some recommended pesticides in agriculture were obtained in pond water. Most of the river water samples (93.7%) were in excess of EC limit (0.50 ng mL-1) of T-pesticides for drinking followed by pond water samples (56.2%). Tubewell water samples were free from T-pesticide threat but exceeded the EC limit (0.10 ng mL-1) for single pesticide in case of chlorpyrifos only. Ecological risk on aquatic animals was observed for OCs in river and chlorpyrifos in pond aquatic ecosystem.

Validation of Multiresidue Method for Analysis of 31 Pesticides in Rice Using Gas Chromatography-Tandem Mass Spectrometry.

Five modified QuEChERS were tested for the multiresidue analysis of 31 pesticides in rice. Rice was spiked with mixture solution of pesticides at 10 ng/g. Method selection was based on the LODs (sensitivity) and recovery tests (accuracy) of the pesticides. Analysis was done in GC-tandem MS in multiple reaction monitoring mode with a total run time of approximately 37 min. The selected method was validated after spiking rice at 20 and 100 ng/g in rice. The performance characteristics of the method impacted for all selected pesticides were acceptable according to the guidelines for method validation (recovery of 70-120% with an RSD of <20% and r2 value of ≥0.99). For rice, matrix effect on the signals of the compounds was corrected by using matrix-matched calibration standards. The LOQs met the requirements of the maximum residue limits for pesticides in rice. The developed method allowed for the simultaneous determination and confirmation of a large number of different groups of pesticides and was fast, simple, inexpensive, and useful for the routine analysis of rice.

Persistence of acetamiprid in paddy and soil under West Bengal agro-climatic conditions.

Acetamiprid insecticide has been widely used to control paddy insects. In order to find out the dissipation of acetamiprid residues in paddy (variety: Satabdi), field studies were conducted in Nadia, West Bengal. Acetamiprid (20% SP) was applied twice at 10 g (T1), 20 g (T2) and 40 g (T3) a.i. ha-1 with three replications along with untreated control (T4). Residue analysis of acetamiprid in paddy (leaf, grain, husk and straw) and soil was conducted utilizing high-pressure liquid chromatograph (HPLC) with UV detector at LOQ of 0.05 mg kg-1. The recoveries of acetamiprid from fortified paddy sample were obtained in the range of 81.8 to 93.1% (for leaf, grain, husk and straw), and for soil, it was 87.2 to 94.3% at the LOQ level and upper two levels of LOQ. The initial residue of acetamiprid (0.11-0.99 mg kg-1) dissipated following the first-order reaction kinetics with the half-life of 1.5 to 1.8 days in paddy leaf and 1.3 to 1.4 days in soil. In harvested samples of paddy straw, grain and soil, the residue was found below LOQ. Because of the rapid dissipation, acetamiprid may be considered to have low risk to the ecosystem. Therefore, the use of acetamiprid for plant protection in paddy may be considered safe for food and environmental health.

Validation of Multiresidue Method for Analysis of 31 Pesticides in Rice Using Gas Chromatography-Tandem Mass Spectrometry.

Five modified QuEChERS were tested for the multiresidue analysis of 31 pesticides in rice. Rice was spiked with mixturesolution of pesticides at 10 ng/g. Method selection was based on the LODs (sensitivity) and recovery tests (accuracy) of the pesticides. Analysis was done in GC-tandem MS in multiple reaction monitoring mode with a total run time of approximately 37 min. The selected method was validated after spiking rice at 20 and 100 ng/g in rice. The performance characteristics of the method impacted for all selected pesticides were acceptable according to the guidelines for method validation (recovery of 70-120% with an RSD of <20% and r2 value of ≥0.99). For rice, matrix effect on the signals of the compounds was corrected by using matrix-matched calibration standards. The LOQs met the requirements of the maximum residue limits for pesticides in rice. The developed method allowed for the simultaneous determination and confirmation of a large number of different groups of pesticides and was fast, simple, inexpensive, and useful for the routine analysis of rice.

Dissipation kinetics of tetraconazole in three types of soil and water under laboratory condition.

Laboratory experiment was conducted to understand the persistence behavior of tetraconazole in three soils of West Bengal (alluvial, red lateritic, and coastal saline) and also in water maintained at three different pH (4.0, 7.0, and 9.2) conditions. Processed soil samples (100 g) were spiked at two treatment doses: 2.5 µg/g (T1) and 5.0 µg/g (T2). Double distilled buffered water (200 ml) was spiked at two treatment doses: 1.0 µg/ml (T1) and 2.00 µg/ml (T2). The tetraconazole dissipation followed first-order reaction kinetics and the residual half-life (T1/2) values in soil were found to be in the range of 66.9-77.2 days for T1 and 73.4-86.0 days for T2. The persistence increased in the order red lateritic > new alluvial > coastal saline. Interestingly, the red lateritic soil exhibited the lowest pH (5.56) and organic carbon (0.52%) content as compared to other two soils. However, the dissipation of tetraconazole in case of water was not pH dependant. The T1/2 values in water were in the range of 94 to 125 days. The study indicated the persistent nature of tetraconazole in soil and water.

Residual fate of the fungicide tetraconazole (4% EW) in mango.

A field trial was carried out to understand the persistence behaviour of tetraconazole in mango and also in the soil of mango orchard following five applications @ 50 g a.i./ha (T(1)) and 100 g a.i./ha (T(2)). The initial deposits were found to be 0.23 and 0.38 µg/g for T(1) and T(2) doses. The theoretical maximum residue contribution (TMRC) of tetraconazole in dietary exposure appeared to be toxicologically safe for consumption as compared with maximum permissible intake (MPI). The half-life values of tetraconazole in mango were in the range of 4-5 days. The harvest samples of mango and soil were free from tetraconazole residues.

Persistence behaviour of thiamethoxam and lambda cyhalothrin in transplanted paddy.

A field study was conducted in Pre-Kharif season 2007 on paddy to determine the persistence of thiamethoxam (12.6%) and lambda cyhalothrin (9.4%) [in a 'Readymix' formulation Alika 247 ZC], following the application of 33 g. a.i. ha⁻¹ (T1) and 66 g. a.i. ha⁻¹ (T2). Spraying of insecticide was done during milking stage of the crop (63 days after transplantation). Thiamethoxam and lambda cyhalothrin residues were estimated by HPLC and GLC respectively. The half-life values were 5.2-5.8 and 4.8 days for thiamethoxam and lambda cyhalothrin respectively. No residue was detected in the harvested paddy, straw, grain, and soil samples.

Effect of chlorpyrifos on microbial biomass and activities in tropical clay loam soil.

Clay loam soil from agricultural field of Gangetic alluvial zone of West Bengal was investigated to evaluate the effect of chlorpyrifos application at field rate (0.5 mg kg(-1) soil) and 100 times of the field rate (50 mg kg(-1) soil) on soil microbial variables under laboratory conditions. Acetone-induced stress on soil microorganisms was evident in the initial stages in terms of microbial biomass carbon (MBC) content in soil and basal soil respiration (BSR) in control soil samples which received acetone only as compared to control soil without acetone. The soil MBC content increased significantly by application of chlorpyrifos. The BSR and the fluorescein diacetate hydrolysing activity (FDHA) were not adversely affected by chlorpyrifos at field rate, whilst the chemical at higher dosage significantly decreased the metabolic activities of soil microbes in terms of BSR and FDHA.

Residual fate and persistence of endosulfan (50 WDG) in Bengal gram (Cicer arietinum).

Residual fate and dissipation pattern of endosulfan (50 WDG) in soil and plant was studied by gas liquid chromatography following twice applications (at 350 g and 700 g a.i. ha(-1)) in chick-pea, Bengal gram (Cicer arietinum) at vegetative and flowering stages of the crop. The initial residues of Endosulfan (alpha + beta + endosulfan sulfate) in plant following second application was 23.40-57.91 microg g(-1) and its maximum deposit in soil was 1.00-2.45 microg g(-1) after 1 day. Dissipation followed first order reaction kinetics and the half-life values were 2.6-2.9 days in green foliage and 4.4-5.0 days in soil. A pre-harvest interval of 14-19 days was recommended for green foliage. No residues were detected in harvested seeds. Maximum concentration of the metabolite endosulfan sulfate was 0.152-0.473 microg g(-1) in soil and 5.42-9.40 microg g(-1) in plant on third day. Endosulfan-beta was more persistent than alpha-isomer attributable to higher conversion of the later to endosulfan sulfate in soil and plant.

Metabolism of chlorpyrifos in relation to its effect on the availability of some plant nutrients in soil.

A laboratory experiment was conducted to study the persistence and metabolism of chlorpyrifos in Gangetic Alluvial soil of West Bengal and also to evaluate their effect on the availability of the major plant nutrients (N, P and K) in soil following the application of chlorpyrifos @ 1 kg (T1), 10 kg (T2) and 100 kg (T3) a.i.ha(-1). The dissipation followed first order kinetics and the calculated half-life (T1/2) values ranged from 20 to 37 days. The primary metabolite of chlorpyrifos, 3,5,6-trichloropyridinol (TCP) was detected from 3rd day after application and was at maximum on 30th day which decreased progressively to non-detectable level (NDL) on 120th day for all the treatment doses. The secondary metabolite 3,5,6-trichloro-2-methoxy pyridine (TMP) was detected on 30th, 15th and 7th day in T1, T2 and T3 doses respectively which decreased to NDL during 90-120th day. ANOVA study revealed significant decrease in the available N and P content in soil treated with chlorpyrifos in comparison to the control set. The inhibitory effect on available N was attributable to TMP and for P it was due to the presence of TCP and TMP rather than chlorpyrifos itself as revealed by the step wise multiple regression technique. In the later stage of incubation, however the average N and P status was recovered significantly at 120 days which might be due to the disappearance of the metabolites. The variation due to time of observations or treatment doses was minimum in case of available K in soil.