Spatiotemporal distribution of potentially toxic elements in the lower Gangetic delta and their implications for non-carcinogenic health risk management
Geoscience Letters volume 8, Article number: 19 (2021)
River Hooghly, a tributary of river Ganges is one of the major rivers of Asia having traditional, social, economic, religious, and spiritual values. Water samples were collected from 18 sampling locations of river Hooghly during summer (dry), monsoon (wet), and winter (cold) seasons. The samples are analysed for basic physicochemical properties and abundance of selected potentially toxic elements (PTEs) are measured. Several PTEs, e.g., Al, Fe, Ni, and Pb, were found to be above the permissible limits, prescribed by national and international guidelines for safe human consumption. The trend of variation in the mean PTE concentrations showed the following order: Cd < Pb < Co < Cr < Ni < Cu < Zn < Mn < Fe. Due to the presence of high total dissolve solid (TDS) and PTE contents, the water quality of river Hooghly is not suitable for direct human consumption. The evaluated Water Quality Index (WQI) value showed a distinct spatio-temporal variation indicating very severe condition of water quality, which is deteriorating gradually from upstream to downstream. In summer, monsoon, and winter, the highest WQI values were observed in Maushuni Island (S15), Petuaghat (S18), and Tapoban (S17), respectively. However, the non-carcinogenic human health risk in terms of Hazard Quotient and Hazard Index values of PTEs indicates no immediate adverse impact on human health due to exposure of PTE contaminated water from river Hooghly through ingestion or dermal route. Though, these risk values for children were higher than adults warranting the adoption of a long-term management plan to cope with potential human health risks. The result suggests implementation of a combination of stringent socio-legal regulations and numerical models for sustainable water related health risk management in river Hooghly.
Riverine freshwater is a major natural resource for ecological sustainability (Rai 2008). Organic and inorganic contaminants or pollutants may enter in the riverine or estuarine systems from a wide range of anthropogenic sources, e.g., industrial and domestic effluents (Amman et al. 2002), storm and surface water run–off (Bhattacharya et al. 2015), agriculture and aquaculture run-off (Ghosh et al. 2016; Mitra et al. 2018a) and natural processes like biogeochemical cycle (Garrett 2000), chemical leaching of bedrocks and water drainage basins (Zhou et al. 2008a, b), sediment resuspension, and ground water inflow (González-Ortegón et al. 2019). Among the organic and inorganic contaminants of water, potentially toxic elements (PTEs) are drawing added attention due to their non-biodegradable nature and accumulation potential through tropic levels causing a long-term effect on the ecosystem. PTEs refer to both metals and non-metals having a range of environmental significance (Nieder et al. 2018). Some PTEs have nutrient-like profiles, such as Copper (Cu) and Cadmium (Cd), suggesting their correlation with biological cycles (Boyé et al. 2012), whereas some other PTEs such as Lead (Pb) possess scavenger like behaviour (Flegal and Patterson 1983). Some of the PTEs such as Cobalt (Co), Copper (Cu), Iron (Fe), Manganese (Mn), and Zinc (Zn) take part in several significant biochemical reactions and act as terminal electron acceptor and micro nutrients (Munoz-Olivas and Camara 2001), but show toxic effects in excess quantities (Low et al. 2015). Some other elements such as Arsenic (As), Cadmium (Cd), and Mercury (Hg) show toxicity in minute quantity (Alves et al. 2014). Thus, use of PTE contaminated water in irrigation may have detrimental effects on local biodiversity including invertebrate and microbial communities hampering ecological balance and sustainability (Kar et al. 2008; Tom et al. 2014; Bhattacharya et al. 2015; Ferreira et al. 2016; Allinson et al. 2017). Moreover, the water qualities of the rivers and estuaries are also regulated by constant influx of contaminated water from several point or non-point sources from upstream making difficult to regulate the water quality (Mitra et al. 2018a).
The estuarine region behaves like a natural filter or buffer zone where the PTEs are adsorbed by the suspended solids and/or might get bio-accumulated in aquatic organisms, e.g., phytoplanktons, zooplankton, benthos, invertebrate, fish, etc. (Tao et al. 2012; Karbassi et al. 2015). Dissolved organic matter (e.g., humic acid, fulvic acid, carbohydrates) also plays a crucial role in regulating PTE concentration in natural streams by forming metal complexes or chelates (Philippe and Schaumann 2014). In the past few decades, public health policy-makers and researchers have focused on increasing anthropogenic input resulting exposure of aquatic habitats to hazardous contaminants due to their toxicity and persistence in natural environment (Upadhyay et al. 2006; Zhou et al. 2008a, b). Toxic elements also had the probability of human health risk (carcinogenic and non-carcinogenic) even at concentration below permissible limit and can be estimated following United States Environmental Protection Agency (USEPA) methods (USEPA 2004; Gao et al. 2019). Seasonal or temporal variations in intensity of agricultural and industrial activity, aquaculture, storm water drainage, atmospheric deposition, and climatic events can have strong influences on the status of river water quality (Singh et al. 2004; Ouyang et al. 2006; Li and Zhang 2010). River Hooghly, a tributary of river Ganges is one of the major rivers of Asia having traditional, social, economic, religious, and spiritual values. About 0.5 billion peoples are directly or indirectly dependent on Ganges river system for their livelihood (Bharati et al. 2016). The region experiences 80% of its annual rainfall between June and September from southwest monsoon (Mukhopadhyay et al. 2006). This strong monsoonal effect might have strong consequences on PTEs inputs to river Hooghly during rainy season. Hence, characterization of seasonal variability of contaminants in this river water is essential for proper evaluation of water quality and assessment of long-term impacts on public health and human welfare. This approach can help to formulate proper policy for reducing contaminants and safeguarding human health and hygiene in the Hooghly river region of the lower Gangetic basin. Although there are several studies (e.g., Sekhar et al. 2005; Mukhopadhyay et al. 2006; Henderson et al. 2007; Sarkar et al. 2007; Pertsemli et al. 2007; Li et al. 2008; Li and Zhang 2010; Mitra et al. 2018a, b), none has emphasised the implication of seasonal and geospatial variations of PTEs for the management of river water quality. To bridge the existing knowledge gap, the present study aims to evaluate geospatial and seasonal water quality and potential non-carcinogenic health risk associated with PTEs in river Hooghly.
Materials and methods
Study area and sampling
River Ganges divides into two major distributaries; Bhagirathi (India) and Padma (Bangladesh) at Mithipur village in Murshidabad district, West Bengal. The tidal regime of river Bhagirathi starting from the downstream of Nabadwip city is known as river Hooghly (Rudra 2014; Ghosh et al. 2016), and serves as a navigable waterway for Kolkata and Haldia ports (Fig. 1). Water samples were collected using clean plastic sampling bottles from a depth of 10 cm in triplicate from 18 sampling stations covering ~ 200 km of River Hooghly in summer (March–May), monsoon (June–September), and winter (November–January) during low tide in 2015–2016 to avoid marine dilution of PTEs and other parameters, readily transferred to the laboratory in ice box and processed (Fig. 1).
Characterization of physicochemical properties and PTEs of water
pH and electrical conductivity (EC) were measured on field using HANNAH Multi parameter (HI-9829-13102). Dissolved oxygen (DO) concentration was measured following Winkler’s method (Winkler 1888; APHA 2017). In laboratory, surface water quality parameters such as total dissolved solid (TDS), salinity, hardness, alkalinity, and chemical oxygen demand (COD) were analysed following protocols as described in APHA (2017). PTEs in water were measured using inductively coupled plasma optical emission spectrometer (ICP-OES) (Thermo Fisher iCAP 7400 ICP-OES). Analytical procedure, accuracy, and precision data have been provided in Additional file 1: Table S1.
A multivariate interpolation method, i.e., inverse distance weighed (IDW) process, was used in ArcGIS software (V10.2) to plot the seasonal geospatial map of studied PTEs. The data were projected to WGS 1984, UTN zone 45 N.
General statistical analyses of physicochemical properties of water were conducted to understand the variation in physicochemical characteristics of water. Pearson product correlation co-efficients, analysis of variance (ANOVA) single factor method followed by post hoc comparison test, i.e., least significant difference (LSD test), and principal component analysis (PCA) between PTEs were done using software SPSS (V16.1) to understand the source and association of the PTEs. Shapiro–Wilk test was also applied to evaluate the normality of the dataset, whereas Kaiser–Meyer–Olkin (KMO) Measure and Barlett’s Test of Sphericity were used to find data adequacy for PCA (Kaiser 1958; Ul-Saufie et al. 2013).
Evaluation of water quality indices (WQI) and risk assessment
Water quality indices (WQI) can be described as a rating that reflects the combined impact of different water quality parameters (Şener et al. 2017; Gao et al. 2019). To calculate WQI, different weights were assigned to each of the measured chemical parameters (Ramakrishnaiah et al. 2009; Yidana and Yidana, 2010). However, risk assessment of the PTEs is a multi-step procedure based on the exposure to and tendency of the PTEs to bioaccumulate within the human body. Human body can be exposed by PTEs from water through consumption/ingestion or dermal routes. Thus, the examined PTEs were compared with reference dosages, and the mean daily intake (MDIingestion and MDIdermal) were estimated for both children and adults as per USEPA Risk Assessment Guidance for Superfund (RAGS) standards (USEPA 1989, 1991, 2004, 2011; Wu et al. 2009; Li and Zhang 2010; Mitra et al. 2018b; Singh et al. 2018; Saleem et al. 2019; Gao et al. 2019). Toxicological profile of the studied elements indicates that all PTEs have toxic carcinogenic or non-carcinogenic human health effects (Luo et al. 2012). Here, the potential degree of non-carcinogenic risk to human population due to ingestion of PTE contaminated water was evaluated as hazard quotients (HQ). Detailed calculation of WQI, risk assessment, and HQ is given in Additional file 1: Table S2.
Physicochemical properties of water
In river Hooghly, physicochemical properties of water in summer, monsoon, and winter season varied between 7.22 and 7.80, 7.23 and 8.00, and 7.19 and 8.00 for pH; 308.0 and 3120, 122 and 3100, and 135 and 3200 µS/cm2 for EC; 568.2 and 2250, 274.6 and 1668.3, and 503.4 and 2023.6 mg/l for TDS, 0.04 and 26.80, 0.09 and 19.80, and 0.08 and 21.78 for salinity; 80.6 and 1881.0, 19.8 and 1485.0, and 22.3 and 1650.4 mg/l for hardness; 136.5 and 1173.0, 126.1 and 1044.3, and 133.2 and 1085.5 mg/l for alkalinity; 3.1 and 4.9, 3.7 and 5.1, and 3.1 and 5.5 mg/l for DO; 16.3 and 52.1, 20.5 and 42.1, and 29.3 and 51.3 mg/l for COD, respectively (Additional file 1: Table S3). In summer, highest value of pH was recorded in Lot 8 (S14), EC, salinity, and DO in Maushuni Island (S15), TDS, hardness, and alkalinity in Tapoban (S17), and COD in Bata (S7). During monsoon, highest value of pH and DO was observed in Panihati (S3), EC, TDS, salinity, alkalinity in Tapoban (S17), and hardness and COD in Chemaguri (S16), whereas in winter, highest value for pH was observed in Shibpur (S6), EC and Salinity in Tapoban (S17), TDS and alkalinity in Petuaghat (S18), hardness in Chemaguri (S16), and DO in 58 Gate and COD in Bata Nagar (S7).
Spatiotemporal distribution of PTEs
The vast study area in River Hooghly is regularly exposed to different sources of natural and anthropogenic inputs and experiences dynamic river processes resulting in varied distribution of PTEs. The average range of concentrations for PTEs in summer, monsoon, and winter varied between 5401.7 and 15,488.5, 4710.8 and 16,988.6, and 6146.6 and 16,287.4 µg/l for Al, 3.7 and 14.1, 2.6 and 9.3, and 4.3 and 18.2 µg/l for Cd, 14.7 and 57.0, 10.6 and 30.7, and 14.4 and 61.6 µg/l for Co, 17.4 and 54.1, 10.7 and 41.5, and 16.0 and 68.4 µg/l for Cr, 34.6 and 76.3, 24.0 and 61.0, and 33.6 and 85.9 µg/l for Cu, 4436.4 and 17,552.1, 4597.9 and 15,111.8, and 6546.9 and 21,461.2 µg/l for Fe, 122.5 and 334.5, 84.0 and 300.8, and 130.9 and 422.5 µg/l for Mn, 24.9 and 63.5, 18.2 and 71.6, and 28.3 and 107.3 µg/l for Ni, 7.9 and 29.8, 6.3 and 25.5, and 10.1 and 35.8 µg/l for Pb, and 37.7 and 101.1, 30.2 and 78.3, and 45.3 and 121.4 µg/l for Zn (Additional file 1: Table S4), respectively, as depicted on the geospatial maps developed using ArcGIS. The colour gradient from blue to red represents the lowest to highest concentration of PTEs (Figs. 2, 3, 4). In summer, highest concentrations of Al, Cd, Cr, and Cu were observed in Nayachar (S12), Co in Tapoban (S17), Fe, Mn, and Pb in Falta (S10), Ni in Shibpur (S6), and Zn in Maushuni Island (S15). During monsoon, maximum concentrations of Cd were found in Petuaghat (S18), Co in Lot 8 (S14), Cr in Haldi estuary (S13), Al and Cu in Nayachar (S12), Fe and Pb in Falta (S10), Mn in Halisahar (S2), Ni in Bata Nagar (S7), and Zn in Shibpur (S6), whereas in winter, the highest concentration of Cd was observed in Haldi estuary (S13), Co in Tapoban (S17), Cr in Petuaghat (S18), Al, Cu, Fe, and Pb in Falta (S10), Mn in Diamond Harbor (S11), Ni in Birlapur (S8), and Zn in Maushuni Island (S15).
Regulation of physicochemical parameters of river Hooghly
The physicochemical profile of a water body is regulated by an interplay of multitude of biological, physical, and anthropogenic processes (Singh et al. 2004; Ouyang et al. 2006; Li and Zhang 2010; Zhang and Gao 2015; Mitra et al. 2018b). pH is a significant physicochemical parameter indicative of the usage of water for drinking and irrigation purpose (Şener et al. 2017), as it can regulate the alkalinity, hardness, and solubility of PTEs in water column (Osibanjo et al. 2011; Şener et al. 2017). A higher pH reduces the solubility of PTEs, while lower pH enhances release of their ions (Singh and Kumar 2017). However, irrespective of the season and sampling stations, the range of pH observed in river Hooghly varies between neutral to sub-alkaline range (7.19–8.00) that is within the WHO guidelines and Indian Standards for safe drinking water (WHO 2008, 2011; BIS 2012).
In general, rivers which are relatively narrow in the upstream and have funnel-shaped wide mouth in the downstream show a steep salinity gradient across the river. A similar pattern of steep salinity gradient is also evident in river Hooghly, as it is a funnel-shaped wide mouthed macro-tidal river (Mukhopadhyay et al. 2006; Rudra 2014). This salinity gradient might be regulating the flocculation of dissolved PTEs, which affects the elemental composition of the river (Samani et al. 2015). Irrespective of the season, the salinity of samples collected from Babughat (S5), the sampling station near Kolkata varies between 0.09 and 0.12. The salinity is found to be lowest in summer, in Babughat (S5) when tidal magnitude or influx is expected to be higher compared to other seasons (Sadhuram et al. 2005; Mukhopadhyay et al. 2006). This indicates that increased magnitude of tidal influx rarely influences salinity of river Hooghly near Kolkata (Samanta et al. 2018) and flocculation of dissolved PTEs at lower saline regime (Samani et al. 2015).
The mean values of EC, TDS, salinity, hardness, and alkalinity show wide range of variation throughout the river, but have direct relation with each other. The post hoc analysis indicates significant statistical variation of Hardness, DO, COD, and TDS (LSD Test; p < 0.05). It was evident from the observed data that the monsoonal downpour has reduced the TDS, EC, salinity, alkalinity, hardness, and COD level of river Hooghly, but DO was increased within the same timeframe. Measured salinity, EC, and TDS show an increasing trend towards mouth of the river Hooghly, which also complements the study of Mitra et al. (2018b). In river Hooghly, the mean values of salinity and TDS are comparatively higher in summer than those in monsoon and winter, which might be due to the combined effect of higher rate of evaporation, higher water temperature, and lower precipitation (Rajasegar 2003; Mukhopadhyay et al. 2006; Mitra et al. 2018b). High TDS concentration in downstream might also be due to dissolved clay particles and sediment resuspension from wide mud flats along both banks of river Hooghly (Batabyal et al. 2014; Ghosh et al. 2019a). The elevated alkalinity of river Hooghly was found to be twice or higher of the permissible limit which indicate the prevalence of bicarbonates (Ghosh et al. 2019a). Irrespective of the sampling station and seasons, water of river Hooghly is found to be very hard (BIS 2012), and due to high TDS, it is not fit for direct human consumption without treatment (WHO 2004, 2008, 2011). The DO values indicate that hypoxic condition does not prevail in river Hooghly (Satpathy et al. 2013) and complements the study of Kazi et al. (2009). However, the observed DO value suggests that water of river Hooghly was suitable for drinking only after proper treatment and disinfection, but might be used directly for the propagation of wildlife and fisheries (BIS 2012). The mean COD values are found to be highest in winter and lowest in summer which might be due to the abundance of microbial population in river Hooghly in summer season as reported by Basu et al. (2013). Moreover, higher COD values in upstream of river Hooghly are due to inflow of domestic and municipal sewage along with agricultural waste and effluents from adjoining industries (Kazi et al. 2009; Pati et al. 2014).
Regulation of geospatial distribution of PTEs
River Hooghly is comparatively well mixed and there is little stratification in the water column (Mukhopadhyay et al. 2006; Samanta and Dalai 2018). In general, irrespective of sampling locations and seasonal changes in river Hooghly, the mean concentrations of PTEs are found to be in the following order Cd < Pb < Co < Cr < Ni < Cu < Zn < Mn < Fe < Al (Table 1) (LSD test; p < 0.05). PTEs like Al, Cd, Fe, Ni, and Pb in water of river Hooghly exceed respective permissible limit prescribed by World Health Organization and Indian Standard (WHO 2008, 2011; BIS 2012). Rapid and unplanned urbanization along with industrialization have homogenized the sources and tidal influx in river Hooghly throughout the year, which might have played a crucial role behind the similar mean spatial distribution or concentration of PTEs in all three seasons (Stucker and Lyons 2017). However, adsorption, flocculations, formation of oxides and/or hydroxides, alumina-silicates, organic chelates, and river water chemistry are major factors which regulate the distribution of PTEs in the water column (Takayanagi and Gobeil 2000). A large quantum (4 × 108 m3) of PTE containing sewage is entering regularly into the river from adjoining urban settlements (Mukhopadhyay et al. 2006). The sewage from the adjoining cities, industrial discharge, and agricultural run-off contains colloidal materials or particles like dissolved organic carbon (DOC) which can form complexes with PTEs by organic ligands (Wen et al. 1999). Moreover, the downstream of river Hooghly is also dominated by mangrove forests, which acts as a major source of DOC. Samani et al. (2015) pointed out that DOC (hydrophobic humic materials) plays a crucial role in the flocculation of PTEs because of salinity gradient. Higher concentrations of Al and Fe are evident as dissolved toxic elements in all of the sampling stations of river Hooghly as Al and Fe are major constituents of the earth crust (Mitra et al. 2018b). PTEs (Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn) might have sourced in river Hooghly from different industrial units comprising paper and pulp, iron and steel, thermal power plant, brick kiln, welding industries, and battery industries, which have been operating on both the banks of the river (Karar and Gupta 2006; Govil et al. 2008; Ghosh et al. 2016, 2019b; Bakshi et al. 2017, 2019; Mitra et al. 2018b).
When compared with other rivers and estuaries around the globe, concentrations of toxic elements measured in river Hooghly are observed to be much higher than Costa Concordia wreck, Han river, Yangtze river, Padma river, Yangzhong water system, and Ghana stream rivers (Asante et al. 2007; Zhou et al. 2008a, b; Wu et al. 2009; Li and Zhang 2010) but lower than Odiel River and Sydney estuary (Olias et al. 2004; Birch and Lee 2018). The PTEs concentration of river Hooghly are also found to be higher than river Padma, Bangladesh (Jolly et al. 2013) which might be due to greater fresh water input in river Padma from river Brahmaputra and river Meghna. While comparing with different rivers of India like Gomti river, Manjira river, Mahanadi river, and Subarnarekha river, the concentration of toxic elements were observed to be higher in river Hooghly, except for Cu which was higher in Manjira river, and Pb and Zn for Gomti river (Senapati and Sahu 1996; Konhauser et al. 1997; Gaur et al. 2005; Krishna et al. 2009). However, the concentration of toxic elements like Cd, Co, and Zn showed a temporal increment when compared with previous studies on the same river (Table 2). Thus, river Hooghly has became a major route or drain for discharge of toxic elements originating from different point and non-point sources like municipal and urban wastes, industrial effluents, and agricultural run-off to the Bay of Bengal.
Statistical analysis to identify potential sources of PTEs
As evident from Additional file 1: Table S5, in river Hooghly throughout the year, the spatial distributions of all potentially toxic elements are correlated with each other (r = 0.217–0.737; n = 162; p < 0.01) except for Ni, which is correlated with Al (r = 0.197; p < 0.05). Cd, Co, Cr, Mn, and Zn show weak positive correlation with Al (r < 0.422) which indicates lesser role of clay minerals in geochemical cycling of these PTEs in river Hooghly. Cu, Fe, and Pb show strong positive correlation with Al suggesting previous association of these elements with clay minerals. However, inter-elemental associations among PTEs suggest that the elements are cycled mostly with a common phase of Fe–Mn oxyhydroxides (Samanta et al. 2017). The positive correlations between PTEs also indicate that they might originate from identical natural/riverine and/or anthropogenic sources having similar mode of movement in the river Hooghly. Higher concentrations of PTEs like Al, Fe, Mn, Co, and Cr can be attributed to various sources, which may be both natural erosion and weathering (Ghosh et al. 2018, 2019a, b; Mitra et al. 2018b) and/or anthropogenic activities; for example, Al can be sourced from foils, garbage, electrical wires, alloy industries (Mitra et al. 2018b); Cd can be originated from fossil fuel, thermal power plants, fertilizer, industrial waste incineration (Caruso and Bishop 2009; Reza and Singh 2010; Raknuzzaman et al. 2016; Mitra et al. 2018b); Co from metal alloys run-off from navigating ships (Mitra et al. 2018b); Cr from textile industries, dyes, pigments; Cu from insecticides, smelting industries, and shipping and boating activities (Shazili et al. 2006; Ghosh et al. 2016, 2019a, b; Ismail et al. 2016); Fe from iron and steel industries, thermal power plant, fossil fuel (Mahato et al. 2014; Mitra et al. 2018b); Mn from paper and pulp industry, power plant, and welding industries (Giri and Singh 2014); Ni from glass and ceramic industries, power plants, automobiles batteries, alloys, and smelting industries (Tariq et al. 2006; Govil et al. 2008); Pb from batteries, fossil fuels, chemical fertilizers (Jumbe and Nandini 2009; Wuana and Okieimen 2011); Zn from fertilizers, synthetic paints, and immersion of idols (Wu et al. 2009; Bhattacharya et al. 2015).
The ANOVA results suggest a statistically significant variation in distribution of toxic elements at all 18 sampling stations and between seasons in river Hooghly at 99.995% confidence level (Additional file 1: Tables S6 and S7). Post hoc analysis additionally reveals significant statistical variation in the distribution of elements amidst the seasons, more specifically between summer and monsoon (LSD test; p < 0.05); except Cr, among monsoon and winter (LSD Test; p < 0.05). However, Co, Ni, and Zn shows statistical significant variation in their distribution between winter and summer (LSD test; p < 0.05). Shapiro–Wilk test was applied to evaluate the normality of the experimental data after transforming the data by taking the base 10 logarithms. Kaiser–Meyer–Olkin (KMO) Measure and Barlett’s Test of Sphericity were used to find data adequacy for PCA. The KMO measure value (0.874) is greater than 0.500, indicating that the data are sufficient and Barlett’s measure of sphericity (p < 0.001) for all examined data shows a higher degree of relationship among the PTEs, suggesting suitability of the data set for performing PCA (p < 0.001) (Kaiser 1958; Ul-Saufie et al. 2013). The result of PCA (VARIMAX rotation mode) suggests that eigen values more than 1 represent 65.9% of the total variance, indicating that distinctive controlling components or sources are responsible for the distribution of dissolved PTEs in river Hooghly. PCA for the PTEs shows two different sources or components in which first principal component (PC-1) have strong positive loadings on Al, Cd, Co, Cr, Cu, and Fe, having 35.6% variability, while second principal components (PC-2) extracted accounted for 65.9% of variability and strong positive loadings among the PTEs like Mn, Ni, Pb, and Zn in river Hooghly (Fig. 5). The components of PC-1 showed correlation with each other indicating similar sources of their origin. They might be the product of natural weathering and erosion of upstream alumina-silicate (quartz, feldspars, mica) and clay minerals containing catchment rocks as Al and Fe is abundant in earth crust (McDonough and Sun 1995; Dalai et al. 2002); Cr is the product of extensive chemical weathering of bed rocks in plains; Cu, Cd, and Co are associated with the carbonate and Fe–Mn oxyhydroxides containing mineral particles (Achyuthan et al. 2002; Ghrefat and Yusuf 2006; Ghosh et al. 2016; Samanta and Dalai 2016; Manon et al. 2019). Fe–Mn oxyhydroxides also play a significant role in geochemical cycling of PTEs in the water column of river Hooghly (Samanta et al. 2017). The components of PC-2 indicate anthropogenic sources of origin as they are found predominantly in municipal and domestic sewage, agricultural run-off, and effluents from industries (Govil et al. 2008; Wuana and Okieimen 2011; Giri and Singh 2014; Bhattacharya et al. 2015; Ghosh et al. 2016, 2018, 2019a, b). The results of both correlation analysis and PCA suggest that the sources of PTEs in water of river Hooghly are combination of both natural and anthropogenic processes.
Evaluation of water quality index
In this study, the water quality of river Hooghly has been evaluated for drinking and other purposes by comparing with permissible or acceptable limits fixed by WHO and Indian standards of drinking and surface water quality (IS 10500: 2012 and IS 2296: 1982) (ISI 1991; WHO 2008, 2011; BIS 2012). Both basic physicochemical parameters like pH, EC, salinity, hardness, alkalinity, DO, COD, TDS, and PTEs like Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were considered to evaluate the WQI. The relative weight (Wr) values are shown in Additional file 1: Table S8. In summer, monsoon, and winter, the WQI values of river Hooghly are found to vary between 373.7 (S2) and 2196.5 (S15), 365.4 (S2) and 1589.5 (S18), and 478.9 (S2) and 1886.2 (S17), respectively (Fig. 4c). WQI values showed increasing trend towards downstream due to high salinity in the mouth of the river and strong tidal amplitude (Mukhopadhyay et al. 2006; Rudra 2014). Irrespective of sampling locations and seasonal changes, the evaluated WQI value of river Hooghly indicates "very severe" condition of water quality which is unsuitable for direct human consumption. This poor condition of water quality might be due to both natural processes like upstream erosion causing influx of sediment loads (Rudra 2014) and anthropogenic activities (Ghosh et al. 2018, 2019a, b; Bakshi et al. 2018, 2019). Moreover, this mangrove dominated estuarine system acts as a source and sink of nutrients and PTEs. Their flow in river Hooghly has been regulated by the input of litter fall and nutrients associated with the sediment particles, which are released during estuarine transport (Mukhopadhyay et al. 2006).
Evaluation of non-carcinogenic human health risk
Non-carcinogenic health risks in terms of MDIingestion, MDIdermal, HQingestion, HQdermal, and HI for summer, monsoon, and winter for adult and child are summarized in Table 3. The MDIingestion and MDIdermal values of Al are found to be highest in summer and monsoon and for Fe in winter, whereas MDIingestion and MDIdermal values of Cd are observed to be lowest irrespective of season and age groups. However, the mean HQingestion and HQdermal values for Co and Cr are observed to be highest, whereas mean HQingestion and HQdermal values of Zn are found to be lowest for both age groups throughout the year. The HQingestion, HQdermal, and HI value for both adult and children are well below the unity, i.e., safe limits suggesting no immediate adverse non-carcinogenic effect on human health due to ingestion or dermal contact of water from river Hooghly. Moreover, the MDIingestion, MDIdermal, HQingestion, HQdermal, and HI values for children are higher in comparison with adults suggesting necessity of long-term measures to mitigate non-carcinogenic human health risks. As evident from Table 3, findings of our study complement with Wang et al. (2017), Xiao et al. (2019), and Gao et al. (2019), and indicate that the children are much more susceptible and vulnerable than adults to PTE exposure. It is also evident from our results that humans are getting PTE exposure predominantly via oral or ingestion route rather than dermal pathways in the study area of River Hooghly where bathing is widely practiced since ages mostly due to religious beliefs, and prawn seed/crab collection is being conducted for the sustenance of livelihood especially for the riverine community of lower Bengal delta. It can also be concluded that at the upstream of river Hooghly, the local inhabitants might be at higher non-carcinogenic risk, as they are consuming river water after filtration and disinfection but getting exposure to dissolved PTEs. A regular exposure to PTEs at this level will be toxic towards human causing long-term irreversible health effects (Singh et al. 2018). Moreover, long-term PTE exposure might also lead to bio-magnification and bio-accumulation of PTEs causing different diseases like cardiovascular problems, damage of kidney, renal cortex and liver, osteoporosis, and developmental retardation (Oyem et al. 2015; Paul 2017; Mitra et al. 2018b).
The deterioration of water quality of river Hooghly due to different natural and anthropogenic processes of varied nature is coupled with a combination of biological and/or physicochemical processes. The pH and other physicochemical properties of river Hooghly such as alkalinity and hardness are in direct relation with each other. Salinity, EC, and TDS show an increasing trend towards mouth of the river Hooghly. The river water is found to be unsuitable for direct human consumption as indicated by the WQI. Increased concentration of PTEs is observed especially near the industrial belt and urban centres surrounding the river belt. The varied accumulation of PTEs at different sampling locations might be due to local tidal amplitude, magnitude of discharge of industrial effluent and municipal sewage, and sedimentation. The concentrations of PTEs like Cd, Co, and Zn show temporal increment in concentration compared to other available reports on river Hooghly. The evaluation of non-carcinogenic human health risk of PTEs indicates no immediate adverse impact due to ingestion or dermal contact of water through bathing or drinking from river Hooghly. However, children are much more susceptible to non-carcinogenic health risks than adults. The results suggest implementation of a combination of legislative regulation, awareness campaign among stake holders, monitoring data, and software based models for risk and vulnerability assessment can be used as a useful tool for improvement of water quality in river Hooghly, which serves as a lifeline of the lower Gangetic delta and supports livelihood of millions.
Availability of data and materials
The research data of this study are given in the additional tables and can be obtained by requesting the corresponding author.
Achyuthan H, Richard Mohan D, Srinivasalu S, Selvaraj K (2002) Trace metals concentrations in the sediment cores of estuary and tidal zones between Chennai and Pondicherry, along the east coast of India. Indian J Mar Sci 31:141–149
Allinson M, Zhang P, Bui A, Myers JH, Pettigrove V, Rose G et al (2017) Herbicides and trace metals in urban waters in Melbourne, Australia (2011–12): concentrations and potential impact. Environ Sci Pollut Res 24(8):7274–7284
Alves RI, Sampaio CF, Nadal M, Schuhmacher M, Domingo JL, Segura-Muñoz SI (2014) Metal concentrations in surface water and sediments from Pardo River, Brazil: human health risks. Environ Res 133:149–155
Amman AA, Michalke B, Schramel P (2002) Speciation of heavy metals in environmental water by ion chromatography coupled to ICP-MS. Anal Bioanal Chem 372(3):448–452
APHA (2017) standard methods for the examination of water and wastewater. In: Baird BR, Eaton AD, Rice EW (eds) American Public Health Association, Washington, DC, 23, 1600
Asante KA, Agusa T, Subramanian A, Ansa-Asare OD, Biney CA, Tanabe S (2007) Contamination status of arsenic and other trace elements in drinking water and residents from Tarkwa, a historic mining township in Ghana. Chemosphere 66(8):1513–1522
Bakshi M, Ram SS, Ghosh S, Chakraborty A, Sudarshan M, Chaudhuri P (2017) Micro-spatial variation of elemental distribution in estuarine sediment and their accumulation in mangroves of Indian Sundarban. Environ Monit Assess 189(5):221
Bakshi M, Ghosh S, Chakraborty D, Hazra S, Chaudhuri P (2018) Assessment of potentially toxic metal (PTM) pollution in mangrove habitats using biochemical markers: a case study on Avicennia officinalis L. in and around Sundarban, India. Mar Pollut Bull 133:157–172
Bakshi M, Ghosh S, Ram SS, Sudarshan M, Chakraborty A, Biswas JK et al (2019) Sediment quality, elemental bioaccumulation and antimicrobial properties of mangroves of Indian Sundarban. Environ Geochem Health 41:1–22
Basu S, Banerjee T, Manna P, Bhattacharyya B, Guha B (2013) Influence of physicochemical parameters on the abundance of Coliform bacteria in an Industrial Site of the Hooghly River, India. Proc Zool Soc 66(1):20–26
Batabyal P, Einsporn MH, Mookerjee S, Palit A, Neogi SB, Nair GB, Lara RJ (2014) Influence of hydrologic and anthropogenic factors on the abundance variability of enteropathogens in the Ganges estuary, a cholera endemic region. Sci Total Environ 472:154–161
Bharati L, Sharma BR, Smakhtin V (eds) (2016) The Ganges River basin: status and challenges in water, environment and livelihoods. Routledge, Abingdon
Bhattacharya BD, Nayak DC, Sarkar SK, Biswas SN, Rakshit D, Ahmed MK (2015) Distribution of dissolved trace metals in coastal regions of Indian Sundarban mangrove wetland: a multivariate approach. J Clean Prod 96:233–243
Birch GF, Lee SB (2018) Baseline physio-chemical characteristics of Sydney estuary water under quiescent conditions. Mar Pollut Bull 137:370–381
Boyé M, Wake B, Garcia PL, Bown J, Baker AR, Achterberg EP (2012) Distributions of dissolved trace metals (Cd, Cu, Mn, Pb, Ag) in the southeastern Atlantic and the Southern Ocean. Biogeosciences 9:3231–3246
Bureau of Indian Standards (BIS) 10500 (2012) Specification for drinking water. Indian Standards Institution, New Delhi, pp 1–5
Caruso BS, Bishop M (2009) Seasonal and spatial variation of metal loads from natural flows in the upper Tenmile Creek watershed, Montana. Mine Water Environ 28(3):166–181
Dalai TK, Krishnaswami S, Sarin MM (2002) Major ion chemistry in the headwaters of the Yamuna river system: chemical weathering, its temperature dependence and CO2 consumption in the Himalaya. Geochim Cosmochim Acta 66(19):3397–3416
Ferreira V, Koricheva J, Duarte S, Niyogi DK, Guérold F (2016) Effects of anthropogenic heavy metal contamination on litter decomposition in streams—a meta-analysis. Environ Pollut 210:261–270
Flegal AR, Patterson CC (1983) Vertical concentration profiles of lead in the Central Pacific at 15 N and 20 S. Earth Planet Sci Lett 64(1):19–32
Gao B, Gao L, Gao J, Xu D, Wang Q, Sun K (2019) Simultaneous evaluations of occurrence and probabilistic human health risk associated with trace elements in typical drinking water sources from major river basins in China. Sci Total Environ 666:139–146
Garrett RG (2000) Natural sources of metals to the environment. Hum Ecol Risk Assess 6(6):945–963
Gaur VK, Gupta SK, Pandey SD, GopalK MV (2005) Distribution of heavy metals in sediment and water of river Gomti. Environ Monit Assess 102(1–3):419–433
Ghosh S, Ram SS, Bakshi M, Chakraborty A, Sudarshan M, Chaudhuri P (2016) Vertical and horizontal variation of elemental contamination in sediments of Hooghly Estuary, India. Mar Pollut Bull 109(1):539–549
Ghosh S, Bakshi M, Kumar A, Ramanathan AL, Biswas JK, Bhattacharyya S et al (2018) Assessing the potential ecological risk of Co, Cr, Cu, Fe and Zn in the sediments of Hooghly-Matla estuarine system. India. Environ Geochem Health 41(1):53–70
Ghosh S, Bakshi M, Mitra S, Mahanty S, Ram SS, Banerjee S et al (2019a) Elemental geochemistry in acid sulphate soils—a case study from reclaimed islands of Indian Sundarban. Mar Pollut Bull 138:501–510
Ghosh S, Majumder S, Roychowdhury T (2019b) Assessment of the effect of urban pollution on surface water-groundwater system of Adi Ganga, a historical outlet of river Ganga. Chemosphere 237:124507
Ghrefat H, Yusuf N (2006) Assessing Mn, Fe, Cu, Zn, and Cd pollution in bottom sediments of Wadi Al-Arab Dam, Jordan. Chemosphere 65(11):2114–2121
Giri S, Singh AK (2014) Assessment of surface water quality using heavy metal pollution index in Subarnarekha River, India. Water Qual Expo Health 5(4):173–182
González-Ortegón E, Laiz I, Sánchez-Quiles D, Cobelo-Garcia A, Tovar-Sánchez A (2019) Trace metal characterization and fluxes from the Guadiana, Tinto-Odiel and Guadalquivir estuaries to the Gulf of Cadiz. Sci Total Environ 650:2454–2466
Govil PK, Sorlie JE, Murthy NN, Sujatha D, Reddy GLN, Rudolph-Lund K et al (2008) Soil contamination of heavy metals in the Katedan industrial development area, Hyderabad, India. Environ Monitor Assess 140(1–3):313–323
Henderson GM et al (2007) GEOTRACES—an international study of the global marine biogeochemical cycles of trace elements and their isotopes. Chem Erde-Geochem 67(2):85–131
ISI (1991) Indian Standard Institute. Drinking water specifications. New Delhi, India
Ismail A, Toriman ME, Juahir H, Zain SM, Habir NLA, Retnam A et al (2016) Spatial assessment and source identification of heavy metals pollution in surface water using several chemometric techniques. Mar Pollut Bull 106(1):292–300
Jolly YN, Akter JS, Kabir AI, Akbar S (2013) Trace elements contamination in the river Padma, Bangladesh. J Phys 13:95–102
Jumbe AS, Nandini N (2009) Impact assessment of heavy metals pollution of Varturlake, Bangalore. J Appl Nat Sci 1(1):53–61
Kaiser HF (1958) Thevarimax criterion for analytic rotation in factor analysis. Psychometrika 23:187–200
Kar D, Sur P, Mandai SK, Saha T, Kole RK (2008) Assessment of heavy metal pollution in surface water. Int J Environ Sci Technol 5(1):119–124
Karar K, Gupta AK (2006) Seasonal variations and chemical characterization of ambient PM10 at residential and industrial sites of an urban region of Kolkata (Calcutta), India. Atmos Res 81(1):36–53
Karbassi AR, Tajziehchi S, Afshar S (2015) An investigation on heavy metals in soils around oil field area. Glob J Environ Sci Manag 1(4):275–282
Kazi TG, Arain MB, Jamali MK, Jalbani N, Afridi HI, Sarfraz RA et al (2009) Assessment of water quality of polluted lake using multivariate statistical techniques: a case study. Ecotoxicol Environ Saf 72(2):301–309
Konhauser KO, Powell MA, Fyfe WS, Longstaffe FJ, Tripathy S (1997) Trace element geochemistry of river sediment, Orissa State, India. J Hydrol 193(1–4):258–269
Krishna AK, Satyanarayanan M, Govil PK (2009) Assessment of heavy metal pollution in water using multivariate statistical techniques in an industrial area: a case study from Patancheru, Medak District, Andhra Pradesh, India. J Hazard Mater 167(1–3):366–373
Li S, Zhang Q (2010) Risk assessment and seasonal variations of dissolved trace elements and heavy metals in the Upper Han River, China. J Hazard Mater 181(1–3):1051–1058
Li S, Xu Z, Cheng X, Zhang Q (2008) Dissolved trace elements and heavy metals in the Danjiangkou Reservoir. China Environ Geol 55(5):977–983
Low KH, Zain SM, Abas MR, Salleh KM, Teo YY (2015) Distribution and health risk assessment of trace metals in freshwater tilapia from three different aquaculture sites in Jelebu Region (Malaysia). Food Chem 177:390–396
Luo XS, Ding J, Xu B, Wang YJ, Li HB, Yu S (2012) Incorporating bioaccessibility into human health risk assessments of heavy metals in urban park soils. Sci Total Environ 424:88–96
Mahato MK, Singh PK, Tiwari AK (2014) Evaluation of metals in mine water and assessment of heavy metal pollution index of East Bokaro Coalfield area, Jharkhand, India. Int J Earth Sci Eng 7(04):1611–1618
Manon K, Mathieu G, Denise B, Maria LT, Laurent M, Maria-Chiara Q, Rémy G (2019) Leaching behavior of major and trace elements from sludge deposits of a French vertical flow constructed wetland. Sci Total Environ 649:544–553
McDonough WF, Sun SS (1995) The composition of the Earth. Chem Geol 120(3–4):223–253
Mitra S, Ghosh S, Satpathy KK, Bhattacharya BD, Sarkar SK, Mishra P, Raja P (2018a) Water quality assessment of the ecologically stressed Hooghly River Estuary, India: a multivariate approach. Mar Pollut Bull 126:592–599
Mitra S, Sarkar SK, Raja P, Biswas JK, Murugan K (2018b) Dissolved trace elements in Hooghly (Ganges) River Estuary, India: Risk assessment and implications for management. Mar Pollut Bull 133:402–414
Mukhopadhyay SK, Biswas HDTK, De TK, Jana TK (2006) Fluxes of nutrients from the tropical River Hooghly at the land–ocean boundary of Sundarbans, NE Coast of Bay of Bengal, India. J Mar Syst 62(1–2):9–21
Munoz-Olivas R, Camara C (2001) Speciation related to human health. In: Ebdon L, Pitts L, Cornelis R, Crews H, Donard OFX, Quevauviller P (eds) Trace element speciation for environment, food and health. The Royal Society of Chemistry, Cambridge, UK, pp 331–353
Nieder R, Benbi DK, Reichl FX (2018) Role of potentially toxic elements in soils. In: Soil components and human health. Springer, Dordrecht
Olıas M, Nieto JM, Sarmiento AM, Cerón JC, Cánovas CR (2004) Seasonal water quality variations in a river affected by acid mine drainage: the Odiel River (South West Spain). Sci Total Environ 333(1–3):267–281
Osibanjo O, Daso AP, Gbadebo AM (2011) The impact of industries on surface water quality of River Ona and River Alaro in Oluyole Industrial Estate, Ibadan, Nigeria. Afr J Biotechnol 10(4):696–702
Ouyang Y, Nkedi-Kizza P, Wu QT, Shinde D, Huang CH (2006) Assessment of seasonal variations in surface water quality. Water Res 40(20):3800–3810
Oyem HH, Oyem IM, Usese AI (2015) Iron, manganese, cadmium, chromium, zinc and arsenic groundwater contents of Agbor and Owa communities of Nigeria. Springerplus 4(1):104
Pati S, Dash MK, Mukherjee CK, Dash B, Pokhrel S (2014) Assessment of water quality using multivariate statistical techniques in the coastal region of Visakhapatnam, India. Environ Monit Assess 186(10):6385–6402
Paul D (2017) Research on heavy metal pollution of river Ganga: a review. Ann Agrar Sci 15(2):278–286
Pertsemli E, Voutsa D (2007) Distribution of heavy metals in lakes doirani and kerkini, northern Greece. J Hazard Mater 148(3):529–537
Philippe A, Schaumann GE (2014) Interactions of dissolved organic matter with natural and engineered inorganic colloids: a review. Environ Sci Technol 48(16):8946–8962
Rai PK (2008) Heavy metal pollution in aquatic ecosystems and its phytoremediation using wetland plants: an ecosustainable approach. Int J Phytorem 10(2):133–160
Rajasegar M (2003) Physico-chemical characteristics of the Vellar estuary in relation to shrimp farming. J Environ Biol 24(1):95–101
Raknuzzaman M, Ahmed MK, Islam MS, Habibullah-Al-Mamun M, Tokumura M, Sekine M, Masunaga S (2016) Assessment of trace metals in surface water and sediment collected from polluted coastal areas of Bangladesh. J Water Environ Technol 14(4):247–259
Ramakrishnaiah CR, Sadashivaiah C, Ranganna G (2009) Assessment of water quality index for the groundwater in Tumkur Taluk, Karnataka State, India. J Chem 6(2):523–530
Reza R, Singh G (2010) Assessment of river water quality status by using water quality index (WQI) in industrial area of Orissa. Int J Appl Environ Sci 5(4):571–580
Rudra K (2014) Changing river courses in the western part of the Ganga–Brahmaputra delta. Geomorphology 27:87–100
Sadhuram Y, Sarma VV, Murthy TR, Rao BP (2005) Seasonal variability of physico-chemical characteristics of the Haldia channel of Hooghly estuary, India. J Earth Syst Sci 114(1):37–49
Saleem M, Iqbal J, Shah MH (2019) Seasonal variations, risk assessment and multivariate analysis of trace metals in the freshwater reservoirs of Pakistan. Chemosphere 216:715–724
Samani AV, Karbassi AR, Fakhraee M, Heidari M, Vaezi AR, Valikhani Z (2015) Effect of dissolved organic carbon and salinity on flocculation process of heavy metals during mixing of the Navrud River water with Caspian Seawater. Desalin Water Treat 55(4):926–934
Samanta S, Dalai TK (2016) Sources and cycling of metals in the Ganga (Hooghly) River estuary, India: role of sediment resuspension and solute–particle interactions. In Goldschmidt conference abstract Vol. 2716
Samanta S, Dalai TK (2018) Massive production of heavy metals in the Ganga (Hooghly) River estuary, India: global importance of solute-particle interaction and enhanced metal fluxes to the oceans. Geochim Cosmochim Acta 228:243–258
Samanta S, Amrutha K, Dalai TK, Kumar S (2017) Heavy metals in the Ganga (Hooghly) River estuary sediment column: evaluation of association, geochemical cycling and anthropogenic enrichment. Environ Earth Sci 76(4):140
Samanta S, Dalai TK, Tiwari SK, Rai SK (2018) Quantification of source contributions to the water budgets of the Ganga (Hooghly) River estuary, India. Mar Chem 207:42–54
Sarkar SK, Saha M, Takada H, Bhattacharya A, Mishra P, Bhattacharya B (2007) Water quality management in the lower stretch of the river Ganges, east coast of India: an approach through environmental education. J Clean Prod 15(16):1559–1567
Satpathy KK, Panigrahi S, Mohanty AK, Sahu G, Achary MS, Bramha SN et al (2013) Severe oxygen depletion in the shallow regions of the Bay of Bengal off Tamil Nadu Coast. Curr Sci 104(11):1467–1469
Schintu M, Marrucci A, Marras B, Atzori M, Pellegrini D (2018) Passive sampling monitoring of PAHs and trace metals in seawater during the salvaging of the Costa Concordia wreck (Parbuckling Project). Mar Pollut Bull 135:819–827
Sekhar C, Chary NS, Kamala CT, Shanker, Frank H (2005) Environmental pathway and risk assessment studies of the Musi River's heavy metal contamination—a case study. Hum Ecol Risk Assess 11(6): 1217–1235
Senapati NK, Sahu KC (1996) Heavy metal distribution in Subarnarekha river, east coast of India. Indian J Mar Sci 25:109–114
Şener Ş, Şener E, Davraz A (2017) Evaluation of water quality using water quality index (WQI) method and GIS in Aksu River (SW-Turkey). Sci Total Environ 584:131–144
Shazili NAM, Yunus K, Ahmad AS, Abdullah N, Rashid MKA (2006) Heavy metal pollution status in the Malaysian aquatic environment. Aquat Ecosyst Health Manag 9(2):137–145
Singh UK, Kumar B (2017) Pathways of heavy metals contamination and associated human health risk in Ajay River basin, India. Chemosphere 174:183–199
Singh KP, Malik A, Mohan D, Sinha S (2004) Multivariate statistical techniques for the evaluation of spatial and temporal variations in water quality of Gomti River (India)—a case study. Water Res 38(18):3980–3992
Singh UK, Ramanathan AL, Subramanian V (2018) Groundwater chemistry and human health risk assessment in the mining region of East Singhbhum, Jharkhand, India. Chemosphere 204:501–513
Stucker JD, Lyons WB (2017) Dissolved trace metals in low-order, urban stream water, Columbus, Ohio. Appl Geochem 83:86–92
Takayanagi K, Gobeil C (2000) Dissolved aluminum in the upper St. Lawrence Estuary. J Oceanogr 56(5):517–525
Tao Y, Yuan Z, Xiaona H, Wei M (2012) Distribution and bioaccumulation of heavy metals in aquatic organisms of different trophic levels and potential health risk assessment from Taihulake, China. Ecotoxicol Environ Saf 81:55–64
Tariq M, Ali M, Shah Z (2006) Characteristics of industrial effluents and their possible impacts on quality of underground water. Soil Environ 25(1):64–69
Tom M, Fletcher TD, McCarthy DT (2014) Heavy metal contamination of vegetables irrigated by urban stormwater: a matter of time? PLoS ONE 9(11):e112441
Ul-Saufie AZ, Yahaya AS, RamliNA RN, Hamid HA (2013) Future daily PM10 concentrations prediction by combining regression models and feedforward backpropagation models with principle component analysis (PCA). Atmos Environ 77:621–630
Upadhyay AK, Gupta KK, Sircar JK, Deb MK, Mundhara GL (2006) Heavy metals in freshly deposited sediments of the river Subernarekha, India: an example of lithogenic and anthropogenic effects. Environ Geol 50(3):397–403
USEPA (1989) Risk Assessment Guidance for Superfund. In: Human Health Evaluation Manual (Part A), vol. 1. United States Environmental Protection Agency, Washington DC. Report EPA/540/1-89/002.
USEPA (1991) United States Environmental Protection Agency, Human Health Evaluation Manual, Supplemental Guidance, Standard Default Exposure Factors. OSWER Dir. 9285. pp 603
USEPA (2004) Risk assessment guidance for superfund. Volume I: human health evaluation manual (Part E, Supplemental Guidance for Dermal Risk Assessment) (Vol. 5). EPA/540/R/99
USEPA (2006) ENERGY STAR overview of 2006 achievements. U.S. Environmental Protection Agency, Climate Protection Partnerships Division, Washington, DC (March 1)
USEPA (2011) Exposure Factors Handbook. United States Environmental Protection Agency. http://cfpub.epa.gov/ncea/risk/recordisplay.cfm.deid.236252
Wang J, Liu G, Liu H, Lam PK (2017) Multivariate statistical evaluation of dissolved trace elements and a water quality assessment in the middle reaches of Huaihe River, Anhui, China. Sci Total Environ 583:421–431
Wen LS, Santschi P, Gill G, Paternostro C (1999) Estuarine trace metal distributions in Galveston Bay: importance of colloidal forms in the speciation of the dissolved phase. Mar Chem 63(3–4):185–212
WHO (World Health Organization) (2008) Guidelines for drinking-water quality (electronic resource), incorporating 1st and 2nd addenda. 3rd edn. World Health Organization, Geneva, Switzerland
WHO (World Health Organization) (2011) Guidelines for Drinking-water Quality, 4th edn. World Health Organization, Geneva, Switzerland
WHO (2004) Water, sanitation and hygiene links to health facts and figures. World Health Organization, Geneva
Winkler LW (1888) The determination of dissolved oxygen in water, Berlin. DeutChem Gas 21:2843–2855
Wu B, Zhao DY, Jia HY, Zhang Y, Zhang XX, Cheng SP (2009) Preliminary risk assessment of trace metal pollution in surface water from Yangtze River in Nanjing Section, China. Bull Environ Contam Toxicol 82(4):405–409
Wuana RA, Okieimen FE (2011) Heavy metals in contaminated soils: a review of sources, chemistry, risks and best available strategies for remediation. ISRN Ecol. https://doi.org/10.5402/2011/402647
Xiao J, Wang L, Deng L, Jin Z (2019) Characteristics, sources, water quality and health risk assessment of trace elements in river water and well water in the Chinese Loess Plateau. Sci Total Environ 650:2004–2012
Yidana SM, Yidana A (2010) Assessing water quality using water quality index and multivariate analysis. Environ Earth Sci 59(7):1461–1473
Zhang J, Gao X (2015) Heavy metals in surface sediments of the intertidal Laizhou Bay, Bohai Sea, China: distributions, sources and contamination assessment. Mar Pollut Bull 98(1–2):320–327
Zhou J, Ma D, Pan J, Nie W, Wu K (2008a) Application of multivariate statistical approach to identify heavy metal sources in sediment and waters: a case study in Yangzhong, China. Environ Geol 54(2):373–380
Zhou Q, Zhang J, Fu J, Shi J, Jiang G (2008b) Biomonitoring: an appealing tool for assessment of metal pollution in the aquatic ecosystem. Anal Chim Acta 606(2):135–150
We are thankful to the Scientific and Engineering Research Board (SR/FT/LS-155/2011 dated 25.04.2013), Department of Science and Technology, Govt. of India for funding this research in University of Calcutta. We are also thankful to the University of Calcutta and CU-UPE facility for providing instrumental and infrastructural facilities.
Scientific and Engineering Research Board (SR/FT/LS-155/2011 dated 25.04.2013), Department of Science and Technology, Govt. of India.
The authors declare that they have no conflict of interests.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Analytical procedure, Accuracy and Precision data of Standard Reference Materials of (SRM 1643f). Table S2. Detailed calculation of WQI, risk assessment and HQ. Table S3. Seasonal physicochemical properties of water of river Hooghly (n = 3 for each site and season). Table S4. Seasonal distribution of PTE in river Hooghly (n = 3 for each site and season). Table S5. Pearson’s Correlation analysis between toxic elements in water of river Hooghly (n = 162). Table S6. ANOVA co-efficients of toxic elements between sampling locations in different seasons. Table S7. ANOVA co-efficients of toxic elements in river Hooghly considering three seasons. Table S8. Relative Weight (Wr) of studied water quality parameters.
About this article
Cite this article
Ghosh, S., Bakshi, M., Mahanty, S. et al. Spatiotemporal distribution of potentially toxic elements in the lower Gangetic delta and their implications for non-carcinogenic health risk management. Geosci. Lett. 8, 19 (2021). https://doi.org/10.1186/s40562-021-00189-5