Apportionment of some chemical elements in soils around the coal mining area in northern Bangladesh and associated health risk assessment

Multivariate statistics and entropy theory for irrigation water quality and entropy-weighted index development in a subtropical urban river, Bangladesh

“…For instrumental calibration, mixed-standard solution of anions prepared from CRM (Fluka Analytical, Sigma Aldrich, Germany) was used as a working standard. In this study, % of spike recovery for all metals and anions were 90-110% which were estimated using suitable equations as reported earlier (Siddique et al 2020).…”

“…Multiple procedure blanks were also prepared for quality assurance. The concentration of metals in digested samples were determined by different arrangements of atomic absorption spectrometers (Models: a. AA240 FS, b. GTA 120-AA240Z, c. SpcetrAA 220, Varian, Australia) following standard method (APHA, 2012;Ahsan et al, 2019;Siddique et al, 2020;Islam et al, 2020b), with a set of characteristic wavelengths of metals using hollow-cathode-lamps and directly aspirating the digested samples into the air-acetylene ame. Instrumental calibration was performed by analyzing the known concentrations of metals in standards.…”

Level of pesticides contamination in the major river systems: A review on South Asian countries perspective

“…While performing these analyses using SPSS software (version 20, IBM Corporation, Armonk, NY, USA), the pesticides and their concentrations as summarized in Table 2 for the considered river water systems were utilized to ensure the statistically valid and significant outcomes from the analyses. Before conducting the multivariate analyses, the assumptions of the normal distribution pattern of the datasets were verified and satisfied by Kolmogorov-Smirnov and Shapiro-Wilk's test of normality (p < 0.05) [38,84]. The results of the normality test (Table S1) showed that all datasets of the considered pesticides for the river water are normally distributed.…”

“…Only those pesticides which are very common in use and reported at a considerable level rather than a very lower level are important to consider for evaluating the effective contamination levels along with their associated probable environmental impact in the studied rivers. For this purpose, the study of the significant associations among the pesticides and the river systems based on their concentration in the samples and also the identification of the probable sources of these chemicals in the rivers are found to be effective and helpful [37,84]. The interrelationships among the reported pesticides and their probabilistic sources in the considered river systems were identified using multivariate statistical analyses such as Principal Component Analysis (PCA), Cluster Analysis (CA), and Pearson's Correlation Matrix (CM) [37,38].…”

“…Based on the knowledge from PCA, hierarchical cluster analysis (CA) for the pesticides and the river systems were performed with Ward's method and the Euclidean distance as a measure of similarity to identify their spatial similarities [38] and to classify the pesticides based on their chemical similarities [84]. In the dendrogram derived from the CA of the pesticides (Figure 5a), three main clusters are differentiated.…”