Techniques for quantification of organochlorine pesticides from a validated method by using gas chromatography-electron capture detector.

Organochlorine pesticides (OCPs) are persistent organic compounds found in aquatic environments worldwide. A well-validated and well-established analytical method is crucial for detecting OCPs in the environment. In this study, an analytical method for quantifying OCPs in water was developed and evaluated. Here, the range of linearity, reproducibility, uncertainty, specificity, method detection limits (MDL), and special emphasis on detection and quantitation limits were assessed. Recovery studies were performed to measure the accuracy and precision of the method. This method exhibited excellent linearity in the range of 2.5-20 µg/L for all compounds. As none of the targeted compounds was detected in the chromatograms of the blank sample with no baseline noise, the limits of detection (LOD) and limits of quantification (LOQ) were determined using the linear regression method, external calibration curve slope, and laboratory fortified blank-based detection. All compounds showed different LOD and LOQ values, depending on the approach used. In particular, endosulfan sulfate, methoxychlor, endrin ketone, H. epoxide, heptachlor, and 4,4'-DDT exhibited high detection limits. The recovery percentage of the 15 compounds at 5 µg/L spiked concentration was between 50 and 150 %, which is consistent with the accuracy of the APHA method. Except for endosulfan sulfate, the relative standard deviations of all other compounds were below 20 %, indicating good precision. This method has also been applied to real water samples. This validation technique is reliable, sensitive, simple, rapid, easy to comprehend, and reproducible. The application of this method in the real water samples was also conducted. Only α-BHC and γ-Chlordane were detected in the water sample.

Dissemination and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in water and sediment of Buriganga and Dhaleswari rivers of Dhaka, Bangladesh.

Concentration, source, ecological and health risks of sixteen polycyclic aromatic hydrocarbons (PAHs) were estimated for water and sediment samples of two urban rivers namely Buriganga River (BR) and Dhaleswari River (DR). The mean concentration of ∑PAHs in BR water and sediment were 9619.2 ngL-1 and 351.6 ngg-1, respectively. Furthermore, the average PAH concentrations detected in DR water and sediment were 1979.1 ngL-1 and 792.9 ngg-1, respectively. The composition profile showed that 3-ring PAHs were dominant in the water matrix; however, 5-ring PAHs were prevalent in the sediment samples of both rivers. Sources apportion study of PAHs indicated that mixed combustion and petroleum sources are responsible for PAHs contamination in the rivers. Ecological risk study of water suggested that the aquatic lives of both rivers are threatened by Fla, BbF, BkF, DahA, and IcdP, as presented above the threshold level. Comparison with sediment quality guidelines (SQGs) indicated that adverse effects might cause occasionally in the sediment ecosystem in DR at certain sampling sites for Nap, Acy, Fl, Phe, Ant, Pyr, Chr, BaP, and DahA. On the other hand, the presence of Nap, Acy and DahA might occasionally cause adverse biological effects in the BR sediment ecosystem. Estimated hazard quotient (HI > 1) and carcinogenic risk (CRtotal > 10-4) values indicated that local inhabitants living in the vicinity of the rivers are prone to high health risks.