Selective effects of fenitrothion on murine splenic T-lymphocyte populations and cytokine/granzyme production

The aim of this study was to investigate in vitro effects of fenitrothion (FNT) on mouse splenic lymphocytes. Here, naïve mice had their spleens harvested and splenocytes isolated. After exposure to FNT for 48 hr: splenocyte viability was measured using a tetrazolium dye assay; cell phenotypes, i.e., B-cells (CD19⁺), T-cells (CD3⁺), and T-cell subsets (CD4⁺ and CD8⁺), were quantified by flow cytometry; and, production of cytokines/granzyme-B was assessed via enzyme-linked immunosorbent assay. The ability for FNT to induce oxidative stress in the cells was evaluated by measuring hydroxyl radical (·OH) and malondialdehyde (MDA) production and changes in glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activity. The results showed that FNT significantly inhibited splenocyte proliferation, and decreased production of interleukin (IL)-2, interferon gamma, IL-4, and granzyme B, but had no impact on IL-6 production. FNT also selectively decreased splenic T-cell levels but did not induce changes in CD19⁺ B-cells. Further, within the T-cell populations, percentages of CD3⁺, CD4⁺, and CD8⁺ T-cells (particularly CD8⁺ T-cells) were reduced. Lastly, FNT selectively increased MDA and ·OH production and inhibited SOD and GSH-Px activities in the splenic lymphocytes. These findings suggest that, due to oxidative damage, FNT selectively inhibits splenic T-lymphocyte survival and cytokine/granzyme production in vitro.     

Persistence characteristics of operationally sprayed fenitrothion in nearby unsprayed areas of a conifer forest ecosystem in New Brunswick

Abstract

Persistence characteristics of operationally sprayed fenitrothion were investigated in various substrates sampled from neighbouring unsprayed areas in New Brunswick. Air, water, sediment, aquatic plants, fish, balsam fir [Abies balsamea (L.) Mill] foliage, forest soil and litter samples were collected from random sampling locations selected within 200 m from the operational spray blocks. The same substrates were resampled from the same plots and from the same locations about a year later just prior to the commencement of the operational spraying. Control samples were collected from an unsprayed site, near Sault Ste. Marie, Ontario. All samples were analysed for fenitrothion, by gas‐liquid chromatography. Except the fish samples all the substrates collected during the time of operational spraying contained low but detectable levels of fenitrothion. When collected a year later prior to the operational spray program, only balsam fir showed any detectable levels (detection limit, 0.01 ppm) of the chemical. All other samples showed no fenitrothion residues (detection limit for air, 10 ng/m³; for water, 0.01 ppb; and for other samples, 0.01 ppm). The findings confirmed that fenitrothion does not persist for an extended period of time in the aquatic substrates. The conifer foliage, however, showed persistent residues at a level of about 0.55 ppm even after the winter months, although there was no indication of accumulation of the chemical as a result of repeated exposure. The study demonstrated that the conifer needles acted as a micro sink for the chemical which showed a tendency to persist in the leaf tissues for a considerable length of time.     

Simultaneous determination of fenitrothion and aminocarb in blueberry foliage and fruits: Application to the analysis of residues in field samples

Abstract

Samples of blueberry foliage and fruits were collected from spray blocks in Ontario after aerial application of fenitrothion and aminocarb at dosage rates of 210 g active ingredient (AI)/ha and 70 g AI/ha respectively. Residues were extracted from the samples by homogenizing with ethyl acetate, cleaned up by microcolumn chromatography using alumina as adsorbent, and analyzed by GLC‐AFID with a glass column packed with 1.5% OV‐17 and 1.95% OV‐210 on 80–100 mesh Chromosorb W‐HP. Average recoveries for fenitrothion and aminocarb from foliage at three fortification levels (1.0, 0.10 and 0.01 ppm) were respectively 99 and 96%. The corresponding values for the fruits were 99 and 95%. Foliage samples collected 1 h post‐spray contained on average 1.13 ppm of fe‐nitrothion and 1.14 ppm of aminocarb. However, residue levels reached below the detection limit (<0.01 ppm) in foliage collected 15 d after treatment. In addition, the fruit samples collected after 15 d post‐spray contained extremely low levels (0.03 ppm for fenitrothion and 0.02 ppm for aminocarb) of residues, and were barely above the detection limit.     

Foliar and ground deposits of fenitrothion following aerial application over a plantation forest

Abstract

Spray deposits were measured on spruce foliage at tree canopy level and on glass plates at ground level, after aerial application of an emulsion formulation of fenitrothion at the rate of 0.21 kg AI in 1.46 L per ha over a 16 ha plot in a plantation forest. Fenitrothion deposits were quantified by gas‐liquid chromatography. A wide variation was observed in deposits on foliage and at the forest floor. Deposits were relatively higher on foliar samples collected from the upwind side of a tree canopy than those on the downwind side. Similarly, the glass plate placed under a tree on the upwind side received relatively higher deposit than the one on the downwind side. However, the glass plates placed in the adjacent forest openings collected markedly higher deposits. Results clearly indicate filtration of the spray droplets by canopy foliage. Assessment of the average deposit of fenitrothion at ground level (mean deposit from all sampling locations) indicated that ca. 19.4% of the applied material reached the forest floor. Within a sampling station, correlation was poor between foliar depsits and those on glass plates under the same trees or in nearby clearings. Analysis of fenitrothion deposits on foliage collected at 1 and 2 h after application indicated that the droplets took, more than 1 h for deposition on the tree canopy. On the other hand, deposition on the glass plates at ground level appeared to be practically complete within 1 h post‐treatment. This was attributed to the higher sedimentation velocities of the larger droplets which tend to travel faster to the floor level than the smaller droplets which float for a longer period near the tree canopy.     

A simplified clean-up procedure for the rapid determination of PCDDs and PCDFs based on retention on activated carbon AX-21

Different 2,3,7,8-substituted polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs) were investigated for their retention behaviour on a disposable minicolumn containing activated carbon AX-21. Elution behaviour and recovery were examined, using native and radiolabelled PCDD and PCDF isomers.

A comparison of the total mass chromatograms of PCDDs and PCDFs in an extract from animal adipose tissue, before and after activated carbon treatment, demonstrates the efficiency of this cleanup step with respect to the elimination of interfering compounds.     

Cyp35a2 gene expression is involved in toxicity of fenitrothion in the soil nematode Caenorhabditis elegans

In this study, the effect of organophosphorous (OP) pesticide, fenitrothion (FT), on the non-target organism was investigated using the soil nematode, Caenorhabditis elegans. Toxicity was investigated on multiple biological levels, from organism to molecular levels, such as, immoblity, growth, fertility, development, acetyl cholinesterase (AChE) activity and stress-response gene expressions. FT may provoke serious consequences on the C. elegans population, as it induced significant developmental disturbance. As expected, FT exposure inhibits AChE activity of C. elegans. The increased expression of the cytochrome p450 family protein 35A2 (cyp35a2) gene was also observed in FT exposed worms. To experimentally demonstrate the relationships between organism-level effects and the cyp35a2 gene expression in FT-exposed C. elegans, the integration of the gene expression with biochemical-, and organism level endpoints were attempted using a C. eleganscyp35a2 RNA interference (RNAi) and cyp35a2 mutant (gk317). The 24 h-EC50s of C. elegans on FT exposure were in the order of cyp35a2 RNAi in cyp35a2 mutant (gk317) > cyp35a2 mutant (gk317) > cyp35a2 RNAi in wildtype (N2) > wildtype (N2). The higher EC50 values of cyp35a2 RNAi and cyp35a2 mutant (gk317) compared to that of wildtypeC. elegans strongly supported that cyp35a2 gene plays an important role in the toxicity of FT towards C. elegans. The experiments with cyp35a2 RNAi also indicated that the development disturbance and decreased AChE activity, which were observed in FT exposed wildtype C. elegans were significantly rescued in the cyp35a2 RNAi C. elegans. Overall results suggest that the cyp35a2 may be an important gene for exerting FT toxicity in C. elegans.     

A simple effective procedure for the determination of adenosine triphosphate in soils

A simple method for the extraction and determination of adenosine 5′-triphosphate (ATP) in soil is described. ATP was extracted by stirring with dimethyl sulphoxide (DMSO), followed by adding 0.01 M trisodium phosphate (Na₃PO₄) buffer solution for a further dispersion. The ATP content was quantitatively measured by luciferin-luciferase system employing a standard addition technique. The method was most efficient in comparison with 7 other extraction procedures. The recoveries of ATP in spiked soil were found to be approximately 100 %. ATP contents in 16 selected soils were in ranges of 0.76±0.05 – 7.79±0.83 μg/g (dry weight). A significant correlation between ATP amounts and biomasses in these soils was also observed.     

A modified clean-up procedure for the determination of PCDDs in soil samples

PCDDs can be determined in soil samples in the presence of high amounts of hexachlorocyclohexanes with a modified method, including a clean-up procedure with a column containing carbon. To reach low detection limits use is made of a column switching system in the GC-MS analysis.     

A rapid method for determination of Aroclor 1260 in cattle adipose tissue

Abstract

A simple analytical procedure for the determination of Aroclor 1260 in cattle adipose tissue is described. The polychlorinated biphenyls residues are extracted from the tissue using a soxhlet extractor and the extracts are cleaned up using a florisil SEP‐PAK cartridge. The residues are detected using a gas chromatograph equipped with an electron capture detector. The effect of extraction time of the Aroclor 1260 residues from the tissue has been investigated and a period of four hours is found to give satisfactory percent recoveries. Greater than 85 percent recoveries were obtained from adipose tissue spiked with Aroclor 1260. The method can be used to detect Aroclor 1260 residue levels as low as 0.10 parts per million.

The method was used to analyze thirty‐one cattle adipose tissue samples out of which twenty‐six samples were taken from cattle suspected of exposure to a pasture containing electrical transformers and capacitors containing Aroclor 1260. Five control samples were collected from cattle with no known exposure. All twenty‐six samples were found to contain non‐detectable Aroclor 1260 residues.     

A rapid spectrophotometric determination of persulfate anion in ISCO

Due to a gradual increase in the use of persulfate as an in situ chemical oxidation (ISCO) oxidant, a simple measurement of persulfate concentration is desirable to analyze persulfate distribution at designated time intervals on/off a site. Such a distribution helps evaluate efficacy of ISCO treatment at a site. This work proposes a spectrophotometric determination of persulfate based on modification of the iodometric titration method. The analysis of absorption spectra of a yellow color solution resulting from the reaction of persulfate and iodide in the presence of sodium bicarbonate reveals an absorbance at 352 nm, without significant interferences from the reagent matrix. The calibration graph was linear in the range of persulfate solution concentration of 0-70 mM at 352 nm. The proposed method is validated by the iodometric titration method. The solution pH was at near neutral and the presence of iron activator does not interfere with the absorption measurement. Also, analysis of persulfate in a groundwater sample using the proposed method indicates a good agreement with measurements by the titration method. This proposed spectrophotometric quantification of persulfate provides a simple and rapid method for evaluation of ISCO effectiveness at a remediation site.     

A new bioseed for determination of wastewater biodegradability: analysis of the experimental procedure

A new bioassay proposed in the patent P201300029 was applied to a pre-treated wastewater containing a mixture of commercial pesticides to simulate a recalcitrant industrial wastewater in order to determine its biodegradability. The test uses a mixture of standardized inoculum of the lyophilized bacteria Pseudomonas putida with the proper proportion of salts and minerals. The results highlight that biodegradation efficiency can be calculated using a gross parameter (chemical oxygen demand (COD)) which facilitates the biodegradability determination for routine water biodegradability analysis. The same trend was observed throughout the assay with the dehydrated and fresh inoculums, and only a difference of 5 % in biodegradation efficiency (E _f) was observed. The obtained results showed that the P. putida biodegradability assay can be used as a commercial test with a lyophilized inoculum in order to monitor the ready biodegradability of an organic pollutant or a WWTP influent. Moreover, a combination of the BOD₅/COD ratio and the P. putida biodegradability test is an attractive alternative in order to evaluate the biodegradability enhancement in water pre-treated with advanced oxidation processes (AOPs).     

水中钙离子现场快速测定方法研究

通过研制一种测试管 ,从而能简便、快速的测定水中的钙离子。该测试管尤其适宜于现场即时监测 ,具有快速、简便、抗干扰能力强和价格低廉等特点     

水分快速分析仪测定城市污泥的含水率

污泥含水率是污水处理、污泥处理及污泥处置利用等环节的重要评估指标。本研究采用快速测定法对不同类型城市污泥含水率进行测定,考察了污泥含水率、质量、颗粒度对测定结果影响,并与国标重量法进行比较。结果表明：污泥质量对快速法测定结果影响较小,原始污泥测定结果标准偏差在0.01%~0.05%之间,常规脱水污泥和生物沥浸脱水污泥测定结果标准偏差均为0.03%;相比国标法,脱水污泥含水率越低,快速法测定结果误差越大,常规脱水污泥和生物沥浸脱水污泥测定结果相对误差分别为-2.09%和-3.49%;脱水污泥颗粒度越大,快速法测定结果偏差越大,常规脱水污泥和生物沥浸脱水污泥总体样本标准偏差分别为0.43%和1.25%。另外发现,在相同干化条件下,生物沥浸脱水污泥相对于常规脱水污泥有较快的水分蒸发速度。针对城市污泥,为缩短测定时间和提高工作效率,待测污泥优选质量≤4 g和颗粒度≤3 mm,且建议只在生产运行中使用,室内科研实验优选国标法。     

A new method for the rapid determination of volatile organic compound breakthrough times for a sorbent at concentrations relevant to indoor air quality

The use of sorbents has been proposed to remove volatile organic compounds (VOCs) present in ambient air at concentrations in the parts-per-billion (ppb) range, which is typical of indoor air quality applications. Sorbent materials, such as granular activated carbon and molecular sieves, are used to remove VOCs from gas streams in industrial applications, where VOC concentrations are typically in the parts-per-million range. A method for evaluating the VOC removal performance of sorbent materials using toluene concentrations in the ppb range is described. Breakthrough times for toluene at concentrations from 2 to 7500 ppb are presented for a hydrophobic molecular sieve at 25%) relative humidity. By increasing the ratio of challenge gas flow rate to the mass of the sorbent bed and decreasing both the mass of sorbent in the bed and the sorbent particle size, this method reduces the required experimental times by a factor of up to several hundred compared with the proposed American Society of Heating, Refrigerating, and Air-Conditioning Engineers method, ASHRAE 145P, making sorbent performance evaluation for ppb-range VOC removal more convenient. The method can be applied to screen sorbent materials for application in the removal of VOCs from indoor air.     

水中氰化物突发性污染事故应急监测方法研究

旨在研究现场快速测定水中的氰化物。运用比色分析的朗伯 比尔定律和真空工艺设计 ,将复杂繁琐的实验室测试方法和操作程序有机地融合在测试管中。该测试管具有快速、简便和价格低廉等特点 ,测定范围为 0 0 0 5— 0 2 0mg/L。     

A simulation procedure for groundwater quality assessments of pesticides

A procedure is described for making regional assessments of pesticide residue loadings and movement in groundwater underneath and downgradient from treated fields. A Monte-Carlo numerical simulation technique is used to generate model parameters for both the unsaturated and saturated zones. Simulations are performed using the Pesticide Root Zone Model linked to a simple groundwater solute transport model.The procedure is useful for evaluating the potential for producing pesticide residues in drinking water wells before actual field applications are made. Appropriate land management options, including restrictions on pesticide application, also can be developed using this procedure.The procedure was used to assess aldicarb levels in northeastern North Carolina groundwater resulting from application of the pesticide to peanuts. Probability density functions for selected soil characteristics were developed using a direct-access soils information data base. Probability density functions for selected groundwater characteristics were developed from available data for the study area. Simulation results indicated that mass fluxes to groundwater exceeded 0.01 and 0.1 kg ha⁻¹ approximately 6.9 and 1.0 percent of the time, respectively. No fluxes exceeded 0.1 kg ha⁻¹ at a distance of 60 m downgradient in any of the cases evaluated.     

A rapid index-system based on plume length and aspect,for source-strength assessment

A pollution index for the rapid assessment of the relative source strength is being herewith recommended for black (combustion) and non-black smokes. The decadic logarithm of the dilution volume in cubio meters, required to make the plume invisible, is proposed as a such index. An advantage of the system is that being based uniquely on visual observation, it requires neither instrumental input nor calculation.     

土壤中苯并[a]芘和二苯并[a，h]蒽的快速测定及其降解特性研究

建立了加速溶剂萃取-高效液相色谱-二极管阵列检测(ASE-HPLC-PAD)快速测定土壤中苯并[a]芘(BaP)和二苯并[a.h]葸(DBA)的方法.通过提取剂、提取方法的优化,检测波长(BaP、DBA的λmax分别为294.6、295.8 nm)的选择,减少了干扰物的影响,提高了检测灵敏度.土壤中添加BaP、DBA的质量浓度均为0.02～0.50 mg/kg时,其平均回收率均为77.26%～109.56%,相对标准偏差为0.60%～2.74%;土壤中BaP、DBA的最小检测质量浓度分别为2.15、1.10μg/kg.将ASE-HPLC-PAD方法应用于污染场地土壤中BaP与DBA的测定及其降解特性研究表明,BaP与DBA的降解半衰期分别达210、693 d.