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International Conference on

Recent Trends in Environmental Sustainability

ESCON22/ETERM/56
Toxicity and bioaccumulation of heavy metals in spinach grown on wastewater irrigated
soil

Aneeza Sardar1, Muhammad Shahid*1, Natasha1, Sana Khalid1, Ghulam Mustafa Shah1,
Muhammad Mubeen1, Muhammad Tahir1
1Department of Environmental Sciences, COMSATS University Islamabad, Vehari- Campus,
61100 Pakistan
Correspondence: muhammadshahid@cuivehari.edu.pk

Abstract
Freshwater scarcity and its contamination by toxic elements are becoming a most alarming
issue worldwide. Cultivation of leafy vegetables by the application of wastewater showed that
there was an elevated level of heavy metals accumulated in these plants. Therefore, the current
study explores the soil contamination, plant (spinach) contamination and human health risks
associated with the heavy metals after wastewater and groundwater irrigation. A pot
experiment was conducted using vegetable (spinach) as a model vegetable and irrigated with
wastewater, freshwater and groundwater alone and in combinations. All the samples
(wastewater, soil and harvested plants) were analyzed for metals concentration including (As,
Cd, Cu, Cr, Fe, Mn, Ni, Pb and Zn) in addition to other physicochemical parameters. Different
human health risks parameters were also measured by the assessment of estimated daily intake,
cancer risk, hazard quotient and integrated index. Elevated level of heavy metals were observed
in canal water and tube-well water as compared to three wastewaters. Moreover, the
concentration of heavy metals was higher in soil irrigated with a combination of wastewater
along with canal water and tube-well water as compared to the wastewater alone. Heavy metals
such as Cu, Cr, Fe, Mn, Pb and Zn significantly increased in the spinach plants. The highest
concentration of heavy metals was present in the plants irrigated with canal water and tube-
well water. The risk indices showed high carcinogenic risk (for As, Cd, Cr and Ni) and non-
carcinogenic risk (for As, Cd, Cu and Pb) from the consumption of metal contaminated spinach.
The integrated health risk parameter such as hazard index (HI) confirmed that As, Cu, Pb and
Zn are major hazardous elements to human health and the consumption of these toxic elements
via ingestion of crops (grown on the wastewater) on daily basis can cause several risks to the
human health. From this study, it is concluded that high concentration of the heavy metals was
present in spinach plants which can induce a number of risks to the human health upon
ingestion. Hence, this study didn’t encourage the use of mixed water treatment for crop
cultivation in the study area (District Vehari).

Keywords: Metals, Hazard index, spinach, carcinogenic risk, Spinach

Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus

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