Risk assessment of trace elements in vegetables grown in river Yamuna floodplain in Delhi.

Urban agriculture is common in fertile river floodplains of many developing countries. However, there is a risk of contamination in highly polluted regions. This study quantifies health risks associated with the consumption of vegetables grown in the floodplain of the urban river 'Yamuna' in the highly polluted yet data-scarce megacity Delhi, India. Six trace elements are analyzed in five kinds of vegetable samples. Soil samples from the cultivation area are also analyzed for elemental contamination. Ni, Mn, and Co are observed to be higher in leafy vegetables than others. Fruit and inflorescence vegetables are found to have higher concentrations of Cr, Pb, and Zn as compared to root vegetables. Transfer Factor indicates that Cr and Co have the highest and least mobility, respectively. Vegetable Pollution Index indicates that contamination levels follow as Cr > Ni > Pb > Zn. Higher Metal Pollution Index of leafy and inflorescence vegetables than root and fruit vegetables indicate that atmospheric deposition is the predominant source. Principal Component Analysis indicates that Pb and Cr have similar sources and patterns in accumulation. Among the analyzed vegetables, radish may pose a non-carcinogenic risk to the age group of 1-5 year. Carcinogenic risk is found to be potentially high due to Ni and Cr accumulation. Consumption of leafy vegetables was found to have relatively less risk than other vegetables due to lower Cr accumulation. Remediation of Cr and Ni in floodplain soil and regular monitoring of elemental contamination is a priority.

Elemental composition of rural household dust in Brahmaputra fluvial plain: insights from SEM-EDS, receptor model, and risk assessment.

The study attempts to look into the morphological characteristics, elemental composition, contamination, source contributions, and associated health risks in household dust of Napaam, a rural region in the Brahmaputra flood plain in North East India. Morphological evidence suggests that most of the house dust particles were sourced from vehicle abrasion and soil. Three contamination indices-enrichment factor (EF), index of geo-accumulation (Igeo), and pollution load index (PLI) indicated that Cl and four trace elements (Cu, Zn, As, and Pb) are significantly enriched in house dust with extreme pollution load. Principal component analysis (PCA) and positive matrix factorization (PMF) revealed 3 potential major sources of elements in house dust-traffic + re-suspension of road dust (35.8%), soil dust (22.2%), and river sediment deposit (16.4%). Two minor sources-biomass burning (13.3%), and construction activities (12.3%) were also identified. Based on health risk assessment (HRA), both children and adult were found to be susceptible to non-carcinogenic and carcinogenic risks.

Health risk assessment of organochlorine pesticide exposure through dietary intake of vegetables grown in the periurban sites of Delhi, India.

The study investigated the levels of organochlorine pesticides (OCPs) in different types of vegetables grown in periurban area of National Capital Region (NCR), India. Vegetable sampling was carried out in winter and summer season of 2012. A total of 20 different OCPs were determined using gas chromatography (GC) assembled with electron capture detector (ECD). Obtained results showed that average levels of ∑(20)OCP ranged from 83.8 ± 25.5 ng g(-1) in smooth gourd to 222.4 ± 90.0 ng g(-1) in cauliflower. The mean concentrations of different OCPs were observed in order of ∑HCH > ∑CHLs > drins > ∑endosulfan > ∑DDT in all vegetables except in brinjal and smooth gourd. Most of the OCP residues recorded in vegetable samples exceeded the maximum residue levels (MRLs) set by international and national regulatory agencies. Health risk assessment suggests that daily dietary OCP exposure via vegetable consumption was higher for children (mean value 4.25E-05) than adults (mean value 2.19E-05). The hazard quotient (HQ) and lifetime cancer risk (LCR) estimated from dietary exposure of these vegetables were above the acceptable limit and can be considered as a serious concern for Delhi population.

Risk assessment of inhalation exposure to polycyclic aromatic hydrocarbons in school children.

Polycyclic aromatic hydrocarbons (PAHs) associated with the inhalable fraction of particulate matter were determined for 1 year (2009-2010) at a school site located in proximity of industrial and heavy traffic roads in Delhi, India. PM10 (aerodynamic diameter ≤10 µm) levels were ∼11.6 times the World Health Organization standard. Vehicular (59.5%) and coal combustion (40.5%) sources accounted for the high levels of PAHs (range 38.1-217.3 ng m(-3)) with four- and five-ring PAHs having ∼80 % contribution. Total PAHs were dominated by carcinogenic species (∼75%) and B[a]P equivalent concentrations indicated highest exposure risks during winter. Extremely high daily inhalation exposure of PAHs was observed during winter (439.43 ng day(-1)) followed by monsoon (232.59 ng day(-1)) and summer (171.08 ng day(-1)). Daily inhalation exposure of PAHs to school children during a day exhibited the trend school hours > commuting to school > resting period in all the seasons. Vehicular source contributions to daily PAH levels were significantly correlated (r = 0.94, p < 0.001) with the daily inhalation exposure level of school children. A conservative estimate of ∼11 excess cancer cases in children during childhood due to inhalation exposure of PAHs has been made for Delhi.

Health risk assessment of polycyclic aromatic hydrocarbons and heavy metals via dietary intake of vegetables grown in the vicinity of thermal power plants.

Six different vegetables grown in the vicinity of three thermal power plants and a background site in Delhi, India were analyzed for 16 priority polycyclic aromatic hydrocarbons (PAHs) and 7 heavy metals (Cd, Cu, Cr, Ni, Zn, Fe and Mn). Annual mean concentrations of PAHs and all metals were found to be significantly higher (ANOVA, p<0.001) at power plant sites as compared to the background site. Higher abundances of coal tracer PAHs such as Phen, Anth, Flan, Pyr and Chry in power plant vegetables suggested possible impacts of coal combustion emissions. Higher ratios of polluted sample-to-background sample of vegetables were found especially for Cr, Cd, Ni and Zn. Spinach and radish showed greater accumulation of PAHs and metals on a mass basis at the power plant sites while vegetables belonging to the gourd family showed highest relative enrichment. Power plant samples showed 184-475% greater metal pollution index (MPI) values as compared to the background location while health risk indices (HRI) for Cd and Ni exceeded the safe limit for most vegetables. Incremental lifetime cancer risk (ILCR) assessment showed that up to 58 excess cancer cases are likely in Delhi for lifetime ingestion exposure to PAHs at their observed concentrations.