X. Chen; H. Jiang; H. Cheng; H. Zheng
Abstract
The current issue of global warming is prominent, and there are many factors that affect global temperature changes. Therefore, how to correctly judge the relationship between each influencing factor and global temperature changes and accurately find out the main reasons of global temperature rise which ...
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The current issue of global warming is prominent, and there are many factors that affect global temperature changes. Therefore, how to correctly judge the relationship between each influencing factor and global temperature changes and accurately find out the main reasons of global temperature rise which are the problems that must be considered and solved to alleviate global warming at present. According to previous official data, this paper proposed a correlation analysis method based on principal components to comprehensively analyze the relationship between natural disaster factors, human factors, and global temperature changes, and find out the main reasons that affect global temperature rise. Compared with traditional research methods, the new method provided in this paper can still remain scientific and accurate calculation results while reducing computational dimensions. The experimental results showed that in the relationship between natural disasters and global temperature changes, the average correlation coefficient of the principal component represented by biological disasters and geological disasters was the highest at 0.6097 and a test value of p<0.05, indicating a significant positive correlation between them and global temperature. However, the correlation coefficient of the principal component represented by floods and storms was negative, indicating a negative correlation between them and global temperature. In exploring the main factors affecting global temperature rise, both the total global population and the total global CO2 emissions had a significant positive correlation with global temperature. Among them, the average correlation coefficient of the total global population was the highest at 0.9972, and its weight also was the highest at 26.42%. Therefore, this indicates that the total global population is the most important factor affecting global temperature rise. This study can provide reference for countries to make decisions in response to global warming.
N. Mamine; F. Khaldi; N. Grara
Abstract
The reuse of wastewaters of urban communes of Khmissa (Site 1), Hannancha (Site 2) and Souk Ahras (Site 3) rejected in the Medjerda wadi of Souk Ahras region (North-East Algeria) for agricultural purposes in the far North-East of Algeria is accompanied by health and environmental risks, the evaluation ...
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The reuse of wastewaters of urban communes of Khmissa (Site 1), Hannancha (Site 2) and Souk Ahras (Site 3) rejected in the Medjerda wadi of Souk Ahras region (North-East Algeria) for agricultural purposes in the far North-East of Algeria is accompanied by health and environmental risks, the evaluation of which requires physico-chemical and parasitological characterization. Biweekly samples were taken from March to August 2019 at the three studied sites wastewaters discharges. The results revealed that the waters studied are characterized by high salt contents, negative redox potential and high levels of turbidity (97.28 ± 18.12 to 111.57 ± 13.11 NTU ), suspended matter (TSS) (351.6 ± 15.52 to 397.33 ± 20.6 mg.L־1), ammonium (8.51 ± 1.94 to 11.19 ± 3.18 mg.L־1) and orthophosphates (3.69 ± 1.40 to 5.29 ± 1.78 mg.L־1), high values in BOD5 (120.62 ± 43.17 to 170.25 ± 32.34 mg.L־1of O2), and COD (286.73 ± 39.65 to358.9 ± 32.81 mg.L־1of O2) as well as the presence of some metallic trace elements such as cobalt (Co) and cadmium (Cd). Parasitological analysis shows high contamination of these irrigation waters by helminthes eggs, which exceed widely the standards of use of waste water in agriculture. The application of Principal Component Analysis (PCA) allowed to conclude that the waters of Medjerda wadi receive urban wastewater from surrounding areas and should not be reused directly in agriculture before being subjected to a processing, in order to improve their quality by meeting the required standards.