Search

This study was carried out to determine sources and health risks of fine particulate (PM2.5) bound polycyclic aromatic hydrocarbons (PAHs) and carbonaceous species in the ambient atmosphere of Delhi. Aerosol samples were collected from October 2017 to September 2018 in an institutional cum residential area of Delhi. Annual PM2.5 level was found to be 124.3 ± 107.6 µg/m3 which exceeded the Indian National Ambient Air Quality Standard (NAAQS) by over three times. Sixteen US EPA priority PAHs’ concentration exhibited a seasonal trend of winter > monsoon > summer with annual mean level of 83.6 ± 48.0 ng/m3. Winter and summer (p summer ≈ monsoon. Molecular diagnostic ratios and principal component analysis identified vehicular emission as the leading source of these species followed by biomass and coal combustion, industrial emissions, and volatilization of petroleum and its products. Regional and trans-boundary incursion of pollutants was also identified with the help of back trajectories and concentration weighted trajectories. Carcinogenic PAHs contributed 41.4% to the aerosol PAHs load. Incremental cancer risk assessment estimated 25 additional cancer cases per million population due to lifetime inhalation exposure to PAHs at their observed concentration in Delhi.

This study characterizes trace metal content in roadside soil and road dust in and around parks of Delhi. Parks in Delhi are generally built in proximity to major traffic roads due to lack of planning and land scarcity. The results indicate similar distribution pattern of trace metals in roadside soil and road dust, in the order Fe > Mn > Zn > Cu > Pb > Ni > Co. The finer fraction ( 1; for road dust) can pose non-carcinogenic risk to exposed children. Carcinogenic risk from particularly Ni exposure was found to be high for all the possible pathways, i.e. ingestion, inhalation and dermal. Risk calculated for exposed population revealed that children are more susceptible to non-cancer risk than the adults. The observed health risk by Ni indicates high carcinogenic risk for the urban population.

Rivers are considered a significant source of fresh water and are vital for society’s sustenance and well-being. Due to rapid urbanization and industrialization, these precious natural resources are being degraded. Melting of Himalayan glaciers and ice is the foremost source of water supply in the Indo Gangetic plains. Also, all major river systems of northern India originate from the Himalayas. The quality of river water in the Himalayas is worsening over the years because of changes in sediment balance, vegetation, land use land cover (LULC) accompanied by anthropogenic activities, inadequately structured sewerage, and drainage system, dumping of treated or untreated effluents, etc. The Himalayan glacial system serves an essential role in creating the headwater streams of the important Himalayan Rivers. Some of which flows across the national boundaries and some through the states of India. This chapter discusses the physical and chemical water quality parameters of some of the Himalayan Rivers in Uttarakhand. The total 11 parameters are taken into account to get insight into the water quality of a few selected rivers in Uttarakhand because of the scarcity of data on the Himalayan River’s water quality. Water quality parameters deliberate in this chapter specify that the water quality of Himalayan River is still good. However, developmental and other activities taking place in and along the rivers pose a threat to it.

Increasing migration to developing urban areas has resulted in human settlements at low lying, urban river floodplain. Groundwater is the primary source of drinking water as well as a key exposure pathway in the poor and marginalized people living near the floodplain. This study investigates seasonal variation in metal pollution, associated health and ecological risk due to exposure to contaminated groundwater of Yamuna River floodplain in Delhi. Trace metal pollution was found to be highest and lowest in summer and winter respectively. Polluted river water, vehicular emissions, agricultural and urban activities were identified as major sources of metals in groundwater. Metal contaminated groundwater was found to pose low to moderate ecological risk. Arsenic was found to pose cancer and non-cancer risk. The risk varied with seasons as winter > summer > monsoon. High non-cancer risk was computed for Mn, having seasonal trend of monsoon > winter > summer. This study infers an urgent need for groundwater quality monitoring in urban river floodplain as it is prone to contamination due to its high permeability and over-exploitation.