A. B. Akolkar

Estimation of Toxicity Equivalency and Probabilistic Health Risk on Lifetime Daily Intake of Polycyclic Aromatic Hydrocarbons from Urban Residential Soils

ABSTRACT In this study, toxicity equivalents and health risks, based on concentration of 16 priority polycyclic aromatic hydrocarbons (PAHs) in urban residential soils were estimated for the human population in Gwalior, India. Benzo(a)pyrene total potency equivalents (BaP TPE) were estimated for assessment of human health risk from direct contact with PAH-contaminated soil. Potential risk to contaminated groundwater from leaching of carcinogenic PAHs was assessed by estimating the index of additive cancer risk (IACR). On the basis of lifetime average daily intake of 16 PAHs through ingestion of PAH-contaminated soils, lifetime cancer risk to human adults and children was estimated. The concentration of probable human carcinogenic PAHs in soils accounted for 38% of ∑16PAHs. BaP TPE and index of additive cancer risk (IACR) were lower than guideline values of 0.6 mg kg−1 and <1, respectively. Estimated lifetime average daily intakes of PAHs via soil ingestion were lower than recommended dose. However, the ILCR for human adults was within acceptable limits recommended by regulatory agencies, but may need action for children in Gwalior, India.

Persistent organic pollutants in residential soils of North India and assessment of human health hazard and risks

Polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) (dichlorodiphenyltrichloroethane, hexachlorocyclohexane, and their isomers) and dioxin-like polychlorined biphenyls (DL-PCBs) in residential soils from North India have been quantified for the assessment of human health risks. The average concentration based on dry weight basis of ∑PAHs, ∑OCPs, and ∑DL-PCBs were 3600 ± 1600, 8.2 ± 1.6, and 3.6 ± 0.8 μg kg−1, respectively. The observed levels were more or less comparable globally and lower than recommended soil quality guidelines. For risk assessment, lifetime average daily doses (LADD) of ∑PAHs, ∑OCPs, and ∑DL-PCBs for human adults were estimated to be 3.5 × 10−6 mg kg−1 d−1, 9.7 × 10−9 mg kg−1 d−1, and 4.4 × 10−11 mg-TEQ kg−1 d−1, and for children 1.8 × 10−5 mg kg−1 d−1, 5.1 × 10−8 mg kg−1 d−1, and 2.3 × 10−10 mg-TEQ kg−1 d−1. The corresponding incremental lifetime cancer risks for human adults were 3.9 × 10−6, 1.2 × 10−8, 6.7 × 10−6, and for children 2.1 × 10−5, 6.5 × 10−8, 3.5 × 10−5, and lower than the acceptable guideline range of 10−6–10−4 for adults but within that range for children. The non-cancer risks due to OCPs and DL-PCBs were less than 1 (≤1.0). It is concluded that cancer and non-cancer risks for humans through PAHs, PCBs and OCPs in these soils are low.

Polychlorinated biphenyls in residential soils and their health risk and hazard in an industrial city in India

Background Polychlorinated biphenyls (PCBs) have never been produced in India, but were used in industrial applications. PCBs have been detected in environmental samples since 1966, and their sources in soils come from depositions of industrial applications, incinerators and biomass combustions. PCBs adsorb to soil particles and persist for long time due to their properties. Their close proximity may also lead to human exposure through ingestion, inhalation, dermal contact, and may exert neurotoxic, mutagenic and carcinogenic health effects. Background Residential soil from Korba, India, was extracted using pressurized liquid extraction procedure, cleaned on modified silica and quantified for PCBs. Soil ingestion was considered as the main exposure pathways of life-long intake of PCBs. Human health risk in terms of life time average daily dose, incremental lifetime cancer risk (ILCR) and non-cancer hazard quotient (HQ) were estimated using established guidelines. Background The estimated average ILCR from non dioxin like PCBs for human adults and children was 3.1×10–8 and 1.1×10–7, respectively. ILCR from dioxin like PCBs for human adults and children was 3.1×10–6 and 1.1×10–5, respectively. The HQ for PCBs was 6.3×10–4 and 2.2×10–3, respectively for human adults and children. Study observed that ILCR from non dioxin like PCBs was lower than acceptable guideline range of 10–6-10–4, and ILCR from dioxin like PCBs was within the limit. HQ was lower than safe limit of 1. Background Study concluded that human population residing in Korba had low health risk due to PCBs in residential soils. Significance for public health The concentrations of polychlorinated biphenyls (PCBs) in soils from an industrial city in India were measured for the assessment of human health risk. PCBs composition profiles were dominated with tri-chlorinated and tetra-chlorinated biphenyls. The possible sources of PCBs contamination can be attributed to local industrial emissions and long range transport depositions. The daily intakes of PCBs, and corresponding incremental lifetime cancer risk and hazard quotient for humans were estimated and found to be lower than acceptable levels. This baseline study may provide database on persistent organic pollutants in tropical countries and may also be useful in risks assessment of the industrial pollutants on human population.

Quantification of nitrophenols, chlorophenols, and hexachlorocyclohexanes in agricultural soils in the vicinity of industrial area for the assessment of human health hazard and risk

ABSTRACT In this study, quantification of nitrophenol (NP), chlorophenol (CP), and hexachlorocyclohexane (HCH) compounds in agricultural soils in the vicinity of the industrial region in northern Uttar Pradesh, India was carried out for the assessment of human health hazard. The concentration of ∑NP, ∑CP, and ∑HCH compounds ranged 0.33–3.64 mg kg−1, 0.06–3.18 μg kg−1, and 1.23–17.24 mg kg−1, respectively, and were within the soil quality guidelines for the protection of human and environment health. Human health hazard index and cancer risk, on the basis of average daily intake of these compounds through soil for human adults and children, was lower than the acceptable limit. This study suggested low health hazard and risk due to phenolic and HCH compounds to human population.

Priority Polycyclic Aromatic Hydrocarbons (PAHs): Distribution, Possible Sources and Toxicity Equivalency in Urban Drains

Wastewater from urban areas constitutes one of the major sources of pollutants contributed to aquatic ecosystem. This study was carried out to elucidate the occurrence and possible source of US Environmental Protection Agency identified 16 priority polycyclic aromatic hydrocarbons (PAHs) in water and sediments from the urban wastewater drains in Delhi, India. A total 60 samples (water and sediment) collected during year 2011–2012, and analyzed the following USEPA methods. Water and sediment samples were extracted using liquid-liquid and ultrasonication techniques, respectively. Glass column chromatography with activated silica was used for sample extracts clean-up, followed by quantification on HPLC equipped with diode array detector at 254 nm wavelength using mixture of acetonitrule and water as mobile phase. Concentrations of total 16 PAHs (∑16PAHs) in all drain water samples ranged from 0.29–35.22 μg/L (mean ± SD, 10.83 ± 10.66 μg/L), predominated by two- and three -ring PAHs. The ∑16PAHs concentrations in all collected sediments ranged between 220–19321 μg/kg (mean±SD, 5574 ± 6820 μg/kg) dry weights. High molecular weight PAHs (≥4-ring PAHs) were dominant in sediment samples. Benzo(a)pyrene equivalent (BaPeq), a relative carcinogenic potential to the corresponding PAHs to BaP was estimated and presented. A selected number of concentration ratios of specific PAHs compounds were calculated and used to diagnose the possible sources of PAHs contamination. The diagnostic ratios reflected pyrogenic input from gasoline or diesel powered vehicular emissions as the major source of PAHs. The levels of PAHs observed in water and sediments were compared with similar studies undertaken in other regions of the world.

Occurrence and Source Apportionment of Polycyclic Aromatic Hydrocarbons in Urban Residential Soils from National Capital Region, Uttar Pradesh, India

This study aims to investigate the level of priority polycyclic aromatic hydrocarbons (PAHs) and identification of their potential sources in residential soils. During the study, a total 36 soil samples collected from twelve residential locations at Sahibabad-Ghaziabad area of western Uttar Pradesh, India, a constituted part of the National Capital Region of India. Samples extracted using ultrasonication, cleaned with silica and analyzed by diode array detector–high-performance liquid chromatography using acetonitrile/water as mobile phase. The 25th and 75th percentile concentration of ∑PAHs was 264 μg kg−1 and 584 μg kg−1, respectively, with mean and median of 445 μg kg−1 and 421 μg kg−1. The detection frequency of PAHs in all samples was lower for low molecular weight PAHs (19%) than high molecular weight PAHs (81%). The concentration of seven probable carcinogenic PAHs accounted for 67% of the ∑PAHs. PAHs toxicity potential as benzo(a)pyrene toxicity equivalent ranged between 2.52–253 μg BaPTEQ kg−1. Composition profile of PAHs with different aromatic rings and selected diagnostic molecular ratios suggested the local pyrogenic sources of PAHs from vehicular emissions, diesel engines, biomass combustion, gasoline, and coal combustions.

Municipal solid waste management at Chennai in southern India – an occupational health perspective

The reasonable concern of India is the health of municipal solid waste (MSW) workers (rag pickers in particular) who scavenge recyclables. A study was conducted among the conservancy staff and rag pickers to examine the occupational health of MSW workers in India. A cross-sectional survey was conducted to collect data on the demographic and socio-economic characteristics of the rag pickers, conservancy staff and residents through a questionnaire survey. The health evaluation was performed using a combination of a detailed medical history, clinical examinations, blood investigations, pulmonary function tests, X-rays and serology on all associated workers. Pulmonary function test results were significantly lower than predicted for both male and female study groups, viz. residents, rag pickers and conservancy workers. Most significant among the findings were the high prevalence of eosinophilia and hepatitis B. Prevalence of 8% hepatitis B carriers among conservancy workers points to the imminent need for prophylactic immunizations within this group of conservancy workers. A high prevalence of eosinophilia is not surprising given the multitude of allergen exposures. As compared to permissible biological exposure indices (BEI) in blood (ACGIH 2005), levels of metals were higher than BEIs, viz. mercury in 10% of workers, lead in 15% of workers, chromium in 12% of workers and cadmium in 3% of workers. As a means of organizing MSW management, the role of informal sector in recycling resources was recognized in the latest Plastic Waste (Management and Handling) Rules, 2011 in India.

Benzo(a)Pyrene Equivalency and Source Identification of Priority Polycyclic Aromatic Hydrocarbons in Surface Sediments from Yamuna River

ABSTRACT Identification of polycyclic aromatic hydrocarbons (PAHs) sources in the environmental compartments is crucial, but there is a need for appropriate management and remediation plan in the environment. PAHs can provide useful information, because they have been utilized for source apportionment. In this study, priority 16 PAHs were determined in sediments from Yamuna River in Delhi for the assessment of their possible sources. Among 16 PAHs, the dominant compounds were fluoranthene, chrysene, fluorine, and pyrene, and their sum accounted for more than 96% of the total 16 priority PAHs. The concentrations of ∑16PAHs at locations between upstream and downstream were not showing any considerable spatial gradient. The concentration of seven probable carcinogenic PAHs ranged 236–6230 µg kg−1 with the mean value of 1897 ± 1740 µg kg−1, and accounted for 40% of the ∑16PAHs. Benzo(a)pyrene toxic equivalent factors (TEFs) used for the quantification of relative toxicity potential of priority PAHs in terms of BaP toxicity equivalency (BaPTEQ) were presented. Homolog profiles demonstrated the dominance of two-, three-, and four-ring PAHs. Composition profile and selected concentration ratios of PAHs were used as diagnostic tools for the identification of possible emission sources of PAHs. The study suggested the pyrogenic activities of petroleum, coal, and biomass combustions as a major source of PAH contamination in the river. However, marginally petrogenic sources from automobile workshops and accidental spillage cannot be ruled out. The observed levels of total PAHs and their toxicity equivalency in sediments were more or less comparable with similar studies carried out worldwide.