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Mentha longifolia (L.) and Lavandula dentata (L.) (Lamiaceae) are two wild growing folk medicine plants that in Saudi Arabia. This work was conducted to investigate the chemical composition and evaluate the fumigant toxicity of their essential oils against the adults (3-5-day-old) of cowpea beetle, Callosobruchus maculatus (F.) (Coleoptera: Bruchidae). The main compounds in M. longifolia oil were pulegone (74.95%), 1,8-cineole (7.35%), l-menthone (6.62%), and eucarvone (2.68%), while the main constituents in L. dentata oil were camphor (61.43%), fenchone (24.3%), d-fenchol (2.15%), and linalool (1.52%). The two oils showed LC 50 values of 4.43 and 7.92 µl/L air and exhibited antiacetylcholinesterase activity with IC50 values of 1.01 and 9.74 µl/ml, respectively. The results proved the potential use of these natural materials as effective alternatives to synthetic pesticides.

This paper presents a cost-effective and validated multi residue modified and miniaturized method for the determination of 220 chemically different groups of pesticides and their isomers. This determination method is performed with single Quaid Gas Chromatography Mass Spectrometry -Total Ion Chromatogram GCMS-TIC. Two methods was experimented and modified with different GCMS parameters to analyses most common used pesticide and their residues in the standers solution and can be applied for real environmental samples. The results showed by single Quaid GCMS-TIC it can analyze 220 pesticides including their isomers within 49.6 min and low detection limit by using modified method 2 as described in this research. Limit of detection (LOD) was ranged from 0.78 to 14.74 ng/ml (ppb) with good separation and resolution. Limit of quantification (LOQ) was ranged between 2.34 and 44.22 ng/ml (ppb). Method 2 was more accurate, shorter, and clear separation rather than method 1. This method can be successfully applied in real environmental samples proven to be a good option for routine analysis of pesticide within the maximum residue limits (MRL) referenced to European commission especially with the most common GCMS-TIC which exists in most of labs and low income countries.

Surface sediment samples from the Arabian Gulf coast of Saudi Arabia were collected by Van Veen grab sampler to identify the characteristics, distribution, levels, and to discriminate between natural and anthropogenic sources of the total extractable organic matter (TEOM). The dried and sieved sediments were extracted with a dichloromethane/methanol mixture for analysis by gas chromatographymass spectrometry. The TEOM included n-alkanes (353.9±283.8 ng.g −1 ), n-alkanols (283.2±296.1 ng.g −1 ), fatty acid methyl esters (245.2±353.7 ng.g −1 ), hopanes (100.7±158.2 ng.g −1 ), steranes (58.5±96.3 ng.g −1 ), triterpenoids (18.9±21.1 ng.g −1 ), steroids (15.3±17.0 ng.g −1 ), polycyclic aromatic hydrocarbons (PAHs) (0.48±1.19 ng.g −1 ), as well as an unresolved complex mixture (UCM =1633±3151 ng.g −1 ) and petrochemicals (343.1±424.2 ng.g −1 ). The major sources of these TEOM compound groups were anthropogenic (petroleum and petrochemical) and natural (lipids from higher plants, marine material, and microbiota) inputs. Anthropogenic contaminants from petroleum products ranged from 46.6-85.6% of the TEOM, whereas petrochemicals varied from 10.7-40.6%. Biogenic in ux from terrestrial vegetation ranged from 5.7-19.3%, and marine biotic sources varied from 11.1-37.5%. The continuous accumulation of anthropogenic contaminants will ultimately affect the critical habitats of this marine coastal region. This provides a basis for further studies to understand human and developmental activities on delivery, deposition processes, distribution, and biogeochemical alteration of organic matter in the coastal zones of the Arabian Gulf. Such studies are important for sustainable development and protection of these key regional habitats.