Polycyclic Aromatic Hydrocarbons Bound to PM 2.5 in Urban Coimbatore, India with Emphasis on Source Apportionment

Coimbatore is one of the fast growing industrial cities of Southern India with an urban population of 1.9 million. This study attempts to evaluate the trends of airborne fine particulates (PM 2.5) and polyaromatic hydrocarbons (PAH) on them. The PM 2.5 mass was collected in polytetra fluoroethylene filters using fine particulate sampler at monthly intervals during March 2009 to February 2010. PAHs were extracted from PM 2.5 and estimated by high-performance liquid chromatography. It is alarming to note that PM 2.5 values ranged between 27.85 and 165.75 μg/m3 and exceeded the air quality standards in many sampling events. The sum of 9 PAHs bound to PM 2.5 in a single sampling event ranged from 4.1 to 1632.3 ng/m3. PAH diagnostic ratios and principal component analysis results revealed vehicular emissions and diesel-powered generators as predominant sources of PAH in Coimbatore

Response Surface Modeling for COD Removal in Electroplating Effluent Using Sacrificial Electrodes by Electro Fenton Process: Optimization and Analysis

The effluent produced by the electroplating industry contains hazardous and toxic chemicals that pose a threat to living organisms and ecosystems. Consequently, it is essential to employ advanced treatment technologies to remove the toxicants from the wastewater. Over the past two decades, the concept of Electro Fenton has been developed and demonstrated as an effective method for significantly alleviating pollutants in wastewater, making it a promising solution for treating wastewater. In the present investigation, the efficiency of the Electro Fenton (EF) process in removing Chemical oxygen demand (COD) from electroplating wastewater using stainless steel as the sacrificial electrode was examined. The influence of various operating parameters, including pH, hydrogen peroxide concentration, reaction time, and Fe2+ concentration, was investigated with the help of Box-Behnken design (BDD) in Response surface methodology (RSM). Notably, EF treatability studies demonstrated that optimal conditions of pH 2, Fe2+ concentration of 0.005M, H2O2 concentration of 0.5M, and RPM of 450 resulted in more than 75% COD removal. Hence, the sacrificial electrodes can be effective in removing COD from the wastewater

Effects of anthropogenic activities on the heavy metal levels in the clams and sediments in a tropical river

The present study aimed to assess the effects of anthropogenic activities on the heavy metal levels in the Langat River by transplantation of Corbicula javanica. In addition, potential ecological risk indexes (PERI) of heavy metals in the surface sediments of the river were also investigated. The correlation analysis revealed that eight metals (As, Co, Cr, Fe, Mn, Ni, Pb and Zn) in total soft tissue (TST) while five metals (As, Cd, Cr, Fe and Mn) in shell have positively and significantly correlation with respective metal concentration in sediment, indicating the clams is a good biomonitor of the metal levels. Based on clustering patterns, the discharge of dam impoundment, agricultural activities and urban domestic waste were identified as three major contributors of the metals in Pangsun, Semenyih and Dusun Tua, and Kajang, respectively. Various geochemical indexes for a single metal pollutant (geoaccumulation index (I geo), enrichment factors (EF), contamination factor (C f) and ecological risk (Er)) all agreed that Cd, Co, Cr, Cu, Fe, Mn, Ni and Zn are not likely to cause adverse effect to the river ecosystem, but As and Pb could pose a potential ecological risk to the river ecosystem. All indexes (degree of contamination (C d), combined pollution index (CPI) and PERI) showed that overall metal concentrations in the tropical river are still within safe limit. River metal pollution was investigated. Anthropogenic activities were contributors of the metal pollution. Geochemical indexes showed that metals are within the safe limit

Influence of Urbanization on Particulate Matter Pollution in Coimbatore City, India

The spatial-temporal distribution of air pollutants over India’s growing cities is still uncertain due to the lack of monitoring data and inadequate knowledge. This study analyzes the temporal and spatial trends of particulate matter in Coimbatore and furthers the influence of urban growth on aerosol concentrations also investigated. The average concentration of PM2.5 and PM10 was 42.23 and 68.05 µg m-3 during the study period and slightly higher than the National Ambient Air Quality Standards. Aerosol concentrations were found to be highest in an industrial site (81.17 µg m-3 for PM10 and 51.89 µg m-3 for PM2.5), medium in urbanindustrial (69.09 µg m-3 for PM10 and 42.53 µg m-3 for PM2.5), commercial (69.99 µg m-3 for PM10 and 42.31 µg m-3 for PM2.5), residential (68.39 µg m-3 for PM10 and 41.21 µg m-3 for PM2.5) sites, and low in the mixed site (51.59 µg m-3 for PM10 and 33.19 µg m-3 for PM2.5). Geographic Information System analysis results indicate that Coimbatore city became more urbanized and more polluted than before. PM2.5/PM10 ratio of 0.60-0.65 in the respective locations revealed the dominance of PM2.5. Vehicular exhaust emissions and road dust resuspension are the primary sources of air quality deterioration in Coimbatore city since there are no other significant pollution sources. Our findings provide baseline information concerning the influence of urbanization and transportation on particulate matter pollution in Coimbatore city.</jats:p