Evaluation of pesticide impact rating index (PIRI) model as a pesticide risk indicator

Systematic methods for assessment of potential risk of pesticides to the environment can be consideredas valuable tools in decision-making and policy formulation. Pesticide Impact Rating Index (PIRI) isa user-friendly simple risk indicator and it can be used to rank pesticides in terms of their mobility. Thepredictions given by using PIRI for the pollution potential of pesticides on shallow ground waterbodies of Kalpitiya area in Sri Lanka was compared with the field experiments. Cultivated areas ofKalpitiya peninsula were selected for field trials.Oxytluorfen for onions, Chlorpyrifos, Diazinon, Dimethoate, Carbofuran, Carbaryl, Mcthornyl,Irnidacloprid, Fenthion and Captan for chili were applied in replicates at recommended applicationrates for particular crops. Each area was irrigated at the rate of 20 mm/day. The soil considered wasthe sandy soil with the organic matter of 1.6±0.2%. Residue levels of applied pesticides were measuredusing Gas Chromatographic and High Performance Liquid Chromatographi methods in irrigation wellsin 100 m diameter area at 3 m depth for 3 months in one week intervals from the time of pesticideapplication. The detected pesticides were confirmed using Gas Chromatographic MassSpectrophotometric method.Out of applied pesticides, Dirnethoate, Carbofuran, and Chlorpyrifos leached 3 m water table in 24±4days, 25±3 days and 3 5±6 days respectively after application of each pesticide. The field monitoringresults were 74% compatible with the predictions from PIRI. This indicates that PIRI can be used asa simple risk indicator model for the prediction of pesticide risk to water bodies.

RISK ASSESSMENT OF PESTICIDE CONTAMINATION POTENTIALS IN EMBILlPITlYA AREA

Embilipitiya is a highly agricultural area, which has consumed a remarkable amount ofagrochemicals in last two decades. Hence pesticide movement level studies are necessaryto prevent the contamination of soil and water by these pesticides.Pesticides Impact Ranking Index (pIRI) is a simple computation model, which can beused for ranking pesticides according to their leaching ability and toxicity levels. Itrequires soil and climatic parameters. chemical and application information of pesticides,etc. The risk levels are indicated as very low, low, medium, high, very high andextremely high according to their leaching and toxicity conditionsThe modeling using PIRI was carried out to rank the most widely used three pesticides,3,4 DPA, Carbfuran and MCPA, for 14 different soil series present in Embilipitiya area.The risk level frequencies were calculated for each pesticide. For 8 soil series high riskleaching potential was obtained. Carbofuran and Walawa series has extremely highleaching potential than others. In comparison, MCPA has a medium risk potential for 10soil series. 3,4 DPA has a very low leaching potential for all soils.Toxicity levels obtained for most of the soil series are low except for Thimbolketiya andWalawa soil series. They have high and medium toxicity levels respectively forcarbofuran. Hence the risk level of carbofuran is very high, MCPA is medium and 3,4DPA is low in different soils present in Embilipitiya area and therefore the usage ofCarbofuran needs to be controlled. In pesticide usage and selection, extra care andawareness procedures are necessary to prevent ground water contamination in future

Weak charge form factor and radius of 208Pb through parity violation in electron scattering

We use distorted wave electron scattering calculations to extract the weak charge form factor F_W(q), the weak charge radius R_W, and the point neutron radius R_n, of 208Pb from the PREX parity violating asymmetry measurement. The form factor is the Fourier transform of the weak charge density at the average momentum transfer q=0.475 fm$^{-1}$. We find F_W(q) =0.204 \pm 0.028 (exp) \pm 0.001 (model). We use the Helm model to infer the weak radius from F_W(q). We find R_W= 5.826 \pm 0.181 (exp) \pm 0.027 (model) fm. Here the exp error includes PREX statistical and systematic errors, while the model error describes the uncertainty in R_W from uncertainties in the surface thickness \sigma of the weak charge density. The weak radius is larger than the charge radius, implying a "weak charge skin" where the surface region is relatively enriched in weak charges compared to (electromagnetic) charges. We extract the point neutron radius R_n=5.751 \pm 0.175 (exp) \pm 0.026 (model) \pm 0.005 (strange) fm$, from R_W. Here there is only a very small error (strange) from possible strange quark contributions. We find R_n to be slightly smaller than R_W because of the nucleon's size. Finally, we find a neutron skin thickness of R_n-R_p=0.302\pm 0.175 (exp) \pm 0.026 (model) \pm 0.005 (strange) fm, where R_p is the point proton radius.Comment: 5 pages, 1 figure, published in Phys Rev. C. Only one change in this version: we have added one author, also to metadat

Moments of the Neutron \u3cem\u3eg\u3c/em\u3e\u3csub\u3e2\u3c/sub\u3e Structure Function at Intermediate \u3cem\u3eQ\u3c/em\u3e\u3csup\u3e2\u3c/sup\u3e

We present new experimental results for the 3He spin structure function g2 in the resonance region at Q2 values between 1.2 and 3.0(GeV/c)2. Spin dependent moments of the neutron were extracted. Our main result, the inelastic contribution to the neutron d2 matrix element, was found to be small at ⟨Q2⟩=2.4(GeV/c)2 and in agreement with the lattice QCD calculation. The Burkhardt-Cottingham sum rule for 3He and the neutron was tested with the measured data and using the Wandzura-Wilczek relation for the low x unmeasured region

A Search for Sigma^0_5, N^0_5 and Theta^++ Pentaquark States

A high-resolution (sigma_instr. = 1.5 MeV) search for narrow states (Gamma < 10 MeV) with masses of M_x approx 1500-1850 MeV in ep -> e'K^+ X, e'K^- X and e' pi^+ X electroproduction at small angles and low Q^2 was performed. These states would be candidate partner states of the reported Theta^+(1540) pentaquark. No statistically significant signal was observed in any of the channels at 90% C.L. Upper limits on forward production were determined to be between 0.7% and 4.2% of the Lambda(1520) production cross section, depending on the channel and the assumed mass and width of the state.Comment: 5 pages, 5 figures, to appear in Phys. Rev. C, update with responses to referee suggestion

Assessment of the impact of diuron to water bodies in the Walawa area

Use of pesticides has significantly increased global food production and it is indispensable in modernagriculture to control weeds, insects, other pests and diseases. As the population increases the use ofpesticides also increases. The impact of these pesticides to the environment is not well understood forSri Lankan conditions Hence the sorption pattern of a non ionic pesticide, diuron {3-(3,4-dichlorophenyl)-l, l-dimethylurea; C9H IICI,KO} which is used as a herbicide to control weeds andmosses mainly in sugarcane, was studIed for-14 soil series in the right bank of the Walawa basin in SriLanka.Information was collected from fanners in Walawa areas on crops, historical cropping patterns, typeof pesticides used, pesticides handling knowledge etc. The survey revealed that pesticides use ismalpracticed by fanners. The distribution of crop types in the area during last three years shows thatPaddy, which is scattered through out the area, is the most prominent crop. The average area underpaddy cultivation is approximately 9800 ha. Banana was the second highest grown crop that is inabout 4200 ha. Sugarcane, which covers about 2500 ha, is the prominent monoculture in the Walawabasin.Adsorption of di uron to the collected surface (0-1 Ocrn) soi Is of the 14 soi I series in the Wa lawa basinwere measured using High Performance Liquid Chromatographic method. The Moraketiya seriesshowed the highest sorption among them. It also gives the highest Kd value of the selected soils andSiyambala series exhibited the lowest adsorption and Kd. The organic carbon content was highest inKachigalara series and it was lowest in the Walawa series. The measured Kd values were used topredict the risk of this pesticide to ground and surface water in the Walawa area using a simplemanagement model called Pesticide Impact Rating Index, PIRI which resulted a moderate risk forthe contamination of water bodies in the area.

Search for a new gauge boson in the A′A' Experiment (APEX)

We present a search at Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling $\alpha'$ to electrons. Such a particle $A'$ can be produced in electron-nucleus fixed-target scattering and then decay to an $e^+e^-$ pair, producing a narrow resonance in the QED trident spectrum. Using APEX test run data, we searched in the mass range 175--250 MeV, found no evidence for an $A'\to e^+e^-$ reaction, and set an upper limit of $\alpha'/\alpha \simeq 10^{-6}$. Our findings demonstrate that fixed-target searches can explore a new, wide, and important range of masses and couplings for sub-GeV forces.Comment: 5 pages, 5 figures, references adde