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The health risk assessment is directly associated with the level of human exposure of the various contaminants, especially heavy metals through different mediums including air, water, and food items. In this study, the heavy metals were also estimated in the aquatic species and most frequently cultivated vegetation species, i.e. sorghum, wheat, grains, and rice, and compared with the standard permissible limits and the previously reported values for the same crops (Table 2.5). Further, the HRI due to heavy metal contamination was calculated as per the standard formula (Khan et al. 2010; Singh et al. 2018) and the guidelines of the United States Environmental Protection Agency (USEPA 2006) for the cultivated crop grains of wheat, maize, and rice to understand the potential human health issues of the dependent population (Figure 2.10).

Table 2.4 Sediment quality parameters of the Kanwar wetland.

Parameters	Current study
Physical parameters
WHC (%)	49.6–65.5
Bulk density (g/cc)	0.77–0.86
pH	6.5–8.76
Electrical conductivity (μS/Cm)	115–136
Macronutrients
Organic carbon (%)	0.14–2.7
Available N (mg/kg)	1110–5831
Available P (mg/kg)	79.1–665
Available K (mg/kg)	89–1017
Available S (mg/kg)	82.2–226.5
Micronutrients, i.e. heavy metals	Sediment quality guidelines
		GRSa	GDSb	UCCc	Ontario MoEd	USEPA
Cr (mg/kg)	34–234	150	97	83	26–110	25–75
Mn (mg/kg)	217–1108	1715	1075	600	460–1100	NA
Cu (mg/kg)	14.6–118	55	25	25	16–110	25–50
Zn (mg/kg)	119–608	106	76	71	120–820	90–200
Pb (mg/kg)	15.6–223	23	NA	17	31–250	NA
Cd (mg/kg)	0–1.6	0.55	NA	0.098	0.6–10	NA

GRS: Ganga river sediments; GDS: Ganga delta sediment; UCC: upper continental crust; MoE: Ministry of Environment; USEPA: United States Environmental Protection Agency.

^a Singh et al. (2003).

^b Datta and Subramanian (1998).

^c McLennan (2001).

^d McDonald et al. (2000).

Table 2.5 Heavy metal content in various species of the Kanwar wetland.

Species	Cr (mg/kg)	Mn (mg/kg)	Cu (mg/kg)	Zn (mg/kg)	Pb (mg/kg)	Cd (mg/kg)
Hydrilla	111–164	116–148	38.5–55	9.6–12.85	133–158	0.89–0.98
Eichhornia	172–224	72–88	48–72	8.0–18	212–252	1.8–2.8
Lotus	28–46	26–42	12–31	6.0–22	114–163	1.02–1.8
Fish	22–36	12.0–26	5.3–21.5	6.24–20	146–172	0.97–1
Sorghum	58–92	12.6–23	22.5–52	4.0–15	217–264	1.01–1.26
Wheat	38.3–42	24–25.7	27.2–39	8.52–9.63	95.9–101	0.98–1.25
Maize	32–34.41	16.5–19	15.2–16.9	7.15–8.27	89–111	0.97–1.1
Rice	42–46.63	8.14–8.93	23–25.44	5.5–6.2	101–105	0.9–1.15
Permissible limit	1a	1b	30b	50b	5c	0.3c
Indian Standardd	20	NA	30	50	2.5	1.5

NA: not available.

^a GB2762 (2012).

^b CODEX (2001).

^c FAO/WHO (2011).

^d Awashthi (2000).

Figure 2.10 Health risk index of heavy metals via cultivated crop grains in the Kanwar wetland.