Quantitation of Pesticide Residue in Water and Food in Louisiana, USA

Pesticides can remain in the environment for decades and contaminate surface water that is used for irrigation of produce. This study examined pesticide residues in some surface waters and foods in Louisiana. Samples of 8 foods (tomato, corn, rice, blueberry, cucumber, cabbage, wheat and melon) and 35 surface waters were studied using a QuEChERS extraction method for food samples and liquid-liquid extraction method for the water samples. Gas chromatography-mass spectrometry was used to analyze water and food samples. Nine pesticides were detected in the surface water samples and 5 in the food samples. Pesticides detected in foods were below FDA tolerance limit but 0.18 ppm cypermethrin found in tomato was within 90% of the FDA limit (0.2 ppm). Four water samples had atrazine levels that were above the FDA limit for potable water. This study suggests the need to intermittently monitor pesticide contamination in our food and water.

Alleviation of Pesticide Residue in Surface Water

Reduction of environmental pollution incurred from pesticide use is very important. Zeolite is a natural mineral capable of removing certain chemical contaminants from water. This study was carried out to test the effect of zeolite treatment on pesticide residue alleviation in surface water. Ten surface water samples were treated with natural zeolite by filtering through. An EPA method was used to extract pesticide residue from the water samples and the surfactant used to modify the net charge on the zeolite was hexadecyltrimethylammonium chloride (HDTMA-Cl). Gas chromatography-mass spectrometry was used to analyze water samples. Alleviation was achieved in all the 10 water samples that were filtered through zeolite. The highest removal of pesticides from water with zeolite included 100% of bifenthrin in sample CLC, atrazine in BPH, CDG and LBT;metolachlor in CLC, LBT, BCH, TRH2 and BPI;acetolachlor in BBH and BCH;azoxystrobin in BBH;desethylatrazine in BCH and BPI;metribuzin in BCH, TRH2 and BPI;and both clomazone and bromacil in sample BDC. A minimum reduction of 10.9% was found for metolachlor in sample BRH. Further reduction of pesticide residues up to 50% was recorded in the SMZ treatment as the concentrations of 4 out of 8 pesticide residues were reduced. This study confirms the potential of both the natural zeolite-Clinoptilolite, and SMZ of alleviating pesticide residues in water.

Application of GC/EIMS in Combination with Semi-Empirical Calculations for Identification and Investigation of Some Volatile Components in Basil Essential Oil

Volatile components in the extracts of basil leaves (Ocimum basilicum L.) were identified by gas chromatography/mass spectrometry (GC/MS) with electron ionization (EI) mode. The major volatile components of basil under investigation are α-pinene, sabinene, β-pinene, d-limonene, eucalyptol, l-linalool and estragole. Electron ionization mass spectra of these compounds have been obtained and investigated. Furthermore, the semi-empirical MNDO [Modified Neglect of Diatomic Overlap] method was used to calculate the thermochemical data for the structural properties of these compounds.

Weeds of Wheat Crop and Their Control Strategies in Dera Ismail Khan District, Khyber Pakhtun Khwa, Pakistan

This study is based on research work conducted during 2008-2010 inDera Ismail Khan, KPK,Pakistan. The research area was extensively surveyed to investigate weed species. About 32 weed species, belonging to two monocot and thirteen dicot families, were collected from the study area. Plants were identified with the help of available literature and by comparing with the already identified plant specimens of the herbarium ofQuaid-i-AzamUniversity,Islamabad,Pakistan. Data inventory constitutes botanical name, vernacular name, English name, family, and flowering and fruiting period. Phalarus minor, Rumax dentatus, and Chenopodium album were the dominant weeds in the study area having comparatively higher relative weed density. Weeds having tough competition with wheat crop for light, moisture, and nutrients adversely affect wheat production. Hence, a constant effort is needed to keep the weed population under control. Many methods of weed control and eradication have been devised but chemical control is the most effective one. However, it may have some environmental consequences if not handled properly.

Earthworm functional groups are related to denitrifier activity in riparian soils

Riparian buffers,located in the transition zone between terrestrial and aquatic ecosystems,are a hotspot for nitrogen(N)removal through denitrification.Earthworms are abundant in riparian buffers and may enhance denitrification.This study investigated earthworm demographics of three earthworm functional groups(anecic,epigeic,and endogeic)and denitrifier activity in temporarily flooded and non-flooded riparian soils from April to October 2012 in southern Quebec,Canada.Nine earthworm species,mostly endogeic,were found in the temporarily flooded soil,while only six earthworm species were found in the non-flooded soil.On average,there were 11.7 times more earthworms with 12.4 times greater biomass(P<0.05)found in the temporarily flooded soil than in the non-flooded soil.The denitrification enzyme activity(DEA)was of similar magnitude in temporarily flooded and non-flooded soils,with temporal variation associated with rainfall patterns.Endogeic earthworm biomass was positively correlated(P<0.05)with DEA,while epigeic earthworm biomass was positively correlated(P<0.05)with 16S rRNA gene copies and nosZ gene copies from bacteria,indicating an association between earthworm functional groups and denitrifier activity in riparian soils.Stepwise multiple regressions showed that DEA in riparian soils could be predicted using soil moisture,inorganic N concentration,and earthworm functional groups,suggesting that endogeic and epigeic earthworms contributed to denitrifier activity in riparian soils.