Analysis of heavy metals found in PM2.5 in Valenzuela using energy dispersive x-ray fluorescence technology

• Main Authors: Maano, John David V., Marzan, Georlene Kiara B.
• Format: text
• Language: English
• Published: Animo Repository 2018
• Subjects: Atmospheric aerosols; Air > Pollution; Air quality management
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/5976
• Institution: De La Salle University

Particulate Matter (PM) 2.5 is known to have adverse effects in human health when people are exposed to it. PM2.5 may come from different sources such as industrial sources and traffic emissions. Valenzuela City, Philippines is established with many industries that may contribute to higher concentrations of heavy metals. For the past years, Valenzuela has also been studied for its accumulation of a specific heavy metal, Lead. This accumulation may not only result due to the emissions from industrial industries but also from traffic emissions. With the use of Energy Dispersive X-ray Fluorescence (EDXRF), 10 air samples, which were all collected in the EMB site located in Valenzuela, were analyzed for the presence of heavy metals. However, only 9 were used for the calculation of concentration of mass in air as samples 3 and 4 were treated as one sample. EDXRF was bound to detect 25 elements, specifically Phosphorus, Sulfur, Titanium, Manganese, Iron, Nickel, Copper, Zinc, Bromine, Strontium, Tin, Antimony, Barium, Neodymium, Sodium, Aluminum, Silicon, Chlorine, Potassium, Calcium, Arsenic, Zirconium, Iodine, Silver, and Lead. Moreover, in the analysis of the concentration in air of these elements, the exact flow rate of the TEOM was not provided by the EMB. The researchers decided to calculate the possible concentration of each elements in each sample if a range of flow rate was used. A range from 0.5 mL/min to 3.0 mL/min, with increments of 0.5 mL/min was used as these are the possible flow rates of the instrument. Almost all the measured concentration in air of the heavy metals were within the standards of safety levels of the Occupational Safety and Health Administration (OSHA) and World Health Organization (WHO), except for the concentration of Lead in sample 7 which exceeded the safety limit of WHO (0.50 ug/m3). For the rest of the analysis, concentration in mass off aerosol (ppm) of these elements were used. The element with the highest mass concentration for all samples is Sulfur (S) with a value of 90000 ppm followed by Iron (Fe) with 26000 ppm and Lead (Pb) with 10000 ppm. Of the heavy metals of interest, Arsenic (As) was detected with the highest concentration of 350 ppm. However, heavy metals Cadmium (Cd,) Chromium (Cr), and Mercury (Hg), were not detected by the EDXRF, thus, their concentrations were not obtained. Correlations between metals were also performed and it was found out that Fe and Cu had correlated with each other with R2 of 0.8474, Fe and Ni with R2 of 0.8577, Fe and I with R2 of 0.7245, Fe and Pb with R2 of 0.8394, Ni and Cu with R2 of 0.8553, Ni and Iodine with R2 of 0.7468, Ni and Pb with R2 of 0.7576, Cu and I with R2 of 0.7086, Cu and Pb with R2 of 0.6068, Zn and Sr with R2 of 0.9721. These data were used for further analysis of PCA. Results in PCA indicated that the possible sources of Lead along with the elements that have correlated with it, are from anthropogenic sources such as plastic and metal productions, gas stations and battery manufacturing present in the South East direction relative to the EMB site in Valenzuela. Cu and Ni was found to have a great correlation with each other based from the dendogram. Hence, the anthropogenic source of these elements may be from gas stations and battery production.