Journal homepage: www.fia.usv.ro/fiajournal

Journal of Faculty of Food Engineering,

Ştefan cel Mare University of Suceava, Romania

Volume XVII, Issue 1- 2018, pag. 53 - 58

COMPARATIVE STUDY OF TOXIC METALS AND MICRONUTRIENTS IN

VEGETABLES IRRIGATED BY SEWAGE/FRESH WATER

Muhammad HAROON

1
, *Muhammad VAQAS

1 Department of Chemistry, Minhajuniversity Lahore, Lahore, Pakistan
2Health, Safety, Enviornment and Quality Department, Attock Refinery Limited, Rawalpindi, Pakistan,

muhammad_vaqas@yahoo.com

*Corresponding author

Muhammad VAQAS
Received November 22th 2017, 23th March 2018

Abstract: The purpose of this study was to compare the concentrations of micronutrients (Maganese,

Zinc, Copper, Iron and Chromium) and toxic metals (Lead and Cadmium) in edible part of ten
different species of vegetables, irrigated by sewage/fresh (tube well) water. It was found that the

irrigation source changes the concentration of micronutrients and toxic metals in the edible part of

vegetables leading to risks for humans’ health.

Keywords: micronutrients, edible part of vegetables, humans’ health risk, effect of irrigation source

1. Introduction

Irrigation is an artificial application of

water to soil. It is used to assist the growth

of agricultural crops, maintenance of

landscapes, and revegetation of disturbed

soils in dry areas, during periods of

inadequate rainfall; irrigation also includes

protecting plants against frost [1].

Vegetables are important protective food,

highly beneficial for the maintenance of

health and prevention of disease.

Increasing fruit and vegetable consumption

up to 600g per day (baseline) could reduce

the total worldwide burden of disease by

1.8% and reduce the burden of ischaemic

heart disease by 31% and ischaemic stroke

by 19%. For stomach, oesophageal, lung

and colorectal cancer, the potential

reductions were 19%, 20%, 12% and 2%

respectively [2].

Manganese is essential for development,

metabolism and the antioxidant system.

Nevertheless, excessive exposure or intake

may lead to neurodegenerative disorder

cause dopaminergic neuronal death [3].

Zinc is typically the second most abundant

transition metal in organisms after iron and

it is the only metal which appears in all

enzyme classes [4].

Excess zinc can be harmful. Excessive

absorption of zinc suppresses copper and

iron absorption. Copper deficiency leads to

tissue injury while high intake may

increase the chances of cancer especial

liver cancer. The patients with

hemochromatosis have high risk of liver

cancer and malignancies [5].

Iron is involved in numerous biological

processes and excess Iron typically

damages cells in the heart, liver and

elsewhere, causing adverse effects that

include coma, metabolic acidosis, shock,

liver failure, coagulopathy, adult

respiratory distress syndrome, long-term

organ damage, and even death [6].

In the form trivalent chromium Cr3+,

chromium is identified as an essential

http://www.fia.usv.ro/fiajournal
mailto:muhammad_vaqas@yahoo.com
http://en.wikipedia.org/wiki/Water
http://en.wikipedia.org/wiki/Soil
http://en.wikipedia.org/wiki/Agriculture
http://en.wikipedia.org/wiki/Landscape
http://en.wikipedia.org/wiki/Revegetation
https://en.wikipedia.org/wiki/Neurodegeneration
https://en.wikipedia.org/wiki/Manganese#cite_note-Emsley2001-23
https://en.wikipedia.org/wiki/Enzyme#Naming_conventions
https://en.wikipedia.org/wiki/Zinc#cite_note-Broadley2007-97
https://en.wikipedia.org/wiki/Heart
https://en.wikipedia.org/wiki/Liver
https://en.wikipedia.org/wiki/Coma
https://en.wikipedia.org/wiki/Metabolic_acidosis
https://en.wikipedia.org/wiki/Shock_(circulatory)
https://en.wikipedia.org/wiki/Liver_failure
https://en.wikipedia.org/wiki/Coagulopathy
https://en.wikipedia.org/wiki/Adult_respiratory_distress_syndrome
https://en.wikipedia.org/wiki/Adult_respiratory_distress_syndrome
https://en.wikipedia.org/wiki/Iron#cite_note-Cheney-152

Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava

Volume XVII, Issue 1 – 2018

Muhammad HAROON, Muhammad VAQAS, Comparative study of toxic metals and micronutrients in vegetables
irrigated by sewage/fresh water, Food and Environment Safety, Volume XVII, Issue 1 – 2018, pag. 53 – 58

nutrient. Its role is important in the action

of insulin [7]. In contrast, hexavalent

chromium Cr6+ is highly toxic and

mutagenic when inhaled [8].

Lead is a toxic metal and primary cause of

lead's toxicity is its interference with a

variety of enzymes because it binds to

sulfhydryl groups found on many enzymes

[9].

Cadmium intake through diet associates to

higher risk of endometrial, breast and

prostate cancer as well as to osteoporosis

in humans [10-12].

The main objective of this survey was to

determine the concentration of

micronutrients and toxic metals in the

edible part of vegetables so all the samples

were collected from Gujrawala, Punjab

Pakistan.

2. Matherials and methods

The collected samples were the edible part

of the vegetables irrigated either by fresh

water (tube well) or sewage water. All the

samples were collected in sunny days,

temperature range 25-30oC in paper bags

with complete labeling of name, date and

location.

The vegetables with some soil and dust

were washed with tap water first and then

with distilled water. All the samples were

primarily dried in open air covered with

filter papers and further dried in an oven at

temperature 70 - 80oC. All the dried

samples were grinded in wooden mortar in

such a way that mortar was cleaned

thoroughly each time after use to avoid the

intermixing of the samples. Sieving of the

grinded samples was done in a stainless

steel sieve of 5 mm mesh. The grinded

samples were kept in air tight polythene

bags labeled with sample number, in a dark

and cool place [13, 14].

The samples were digested by taking one

gram of the dried sample in a 100 ml

beaker and added 20 ml nitric acid (conc.).

The beaker was covered with a watch glass

and was allowed to stand for two hours

then placed on a hot plate inside a fuming

chamber until the solid particles nearly

disappeared then removed from hot plate

and allowed to cool. After that 10 ml of

72% perchloric acid was added and again

placed on the hot plate. Heated gently first

and then vigorously until solution in

beaker became clear and volume reduced

to about 5-6 ml then cooled and added 3ml

of 50% hydrochloric acid, again heated on

hot plate until volume of the solution is

reduced to 5 ml at the end it was allowed

to cool and added some distilled water.

The solution was transferred carefully to

100 ml measuring flask and made the

volume up to mark with distilled water,

shacked well and allowed to stand

overnight, filtered, and collected in labeled

plastic bottles. All the samples prepared

likewise and stored in dark. A blank test

solution was also prepared by adopting the

same procedure without taking vegetable

sample [15].

All the vegetable samples were analyzed

by atomic absorption spectrometer [Perkin

Elemer PinAAcleTM 900T] and

calculations were performed by following

formula [16].

Metal in vegetable sample:

(mg/kg) = (S-B)*dt*V / W

S = Sample Reading; B = Blank Reading;

dt = Dilution factor; V = Volume of first

dilution; W = Weight of sample.

3. Results and discussion

Manganese (Mn): The highest

concentration of manganese was found

94,53mg/kg in the Spinach (Spinacia

oleracea) grew near drain nala in the

village of Kot Mand Gujranwala and

irrigated with sewage water which comes

out from industries and houses. The

concentration of manganese was observed

in the range of 10,34 – 94,53 mg/kg in the

https://en.wikipedia.org/wiki/Chromium#cite_note-53
https://en.wikipedia.org/wiki/Hexavalent_chromium
https://en.wikipedia.org/wiki/Hexavalent_chromium
https://en.wikipedia.org/wiki/Mutagen
https://en.wikipedia.org/wiki/Chromium#cite_note-58
https://en.wikipedia.org/wiki/Enzyme
https://en.wikipedia.org/wiki/Sulfhydryl_group
https://en.wikipedia.org/wiki/Lead#cite_note-Pearson03-181

Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava

Volume XVII, Issue 1 – 2018

vegetable samples irrigated with sewage

water. The level of manganese was found

to be 8,75 – 78,78 mg/kg in the vegetables

irrigated with fresh water. In the nine

vegetable species, the manganese found

higher in the vegetables irrigated with

sewage water and lower in the vegetables

irrigated with fresh water (Fig. 1).

Fig. 1. Manganese (mg/Kg)

Zinc (Zn): The level of zinc in the

vegetables irrigated with sewage water was

ranged from 8,82 – 23,26 mg/kg. In the

nine vegetable species, the level of zinc

was found higher in the vegetables

irrigated with sewage water and lower in

the vegetables irrigated with fresh water.

The level of zinc in the vegetables irrigated

with fresh water was found in the range of

4,28 – 14,28 mg/kg. Similar concentration

of zinc was observed in the vegetable

specie Radish (Raphanus Sativus) irrigated

with both type of irrigation waters (Fig. 2).

Fig. 2. Zinc (mg/Kg)

Copper (Cu): The level of copper in the

vegetables irrigated with sewage water was

found in the range of 8,86 – 26,57 mg/kg.

The concentration of copper in the

vegetables irrigated with fresh water was

determined to be 16,84 – 5,80 mg/kg. The

highest amount of copper was found

26,57mg/kg in the fenu-greek (Trigonella

foenum - graecum) grew near drain nala in

the village of Qila Deso Singh Gujranwala

and irrigated with sewage water (Fig. 3).

Fig. 3. Copper (mg/Kg)

Iron (Fe): The concentration of iron in the

vegetables irrigated with sewage water was

found to be 48 - 584 mg/kg. In the eight

vegetable species, the amount of iron was

found higher in the vegetables irrigated

with sewage water and lower in the

vegetables irrigated with fresh water. The

concentration of iron in the vegetables

irrigated with fresh water was determined

to be 30 – 412 mg/kg. The highest amount

of iron was found 584 mg/kg in the

Spinach (Spinacia oleracea) grew near

drain nala in the village of Kot Mand

Gujranwala and irrigated with sewage

water which comes out from industries and

houses (Fig. 4).

Fig. 4. Iron (mg/Kg)

Chromium (Cr): It was examined that

most of the vegetables irrigated with

Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava

Volume XVII, Issue 1 – 2018

sewage water contained the higher

concentrations of chromium as compared

to the vegetables irrigated with fresh water.

The concentration of chromium in the

vegetables irrigated with fresh water was

evaluated in the range of 0.17 - 1.34mg/kg.

The chromium concentration in the

vegetables irrigated with sewage water was

determined to be 0.09 - 2.30 mg/kg. The

concentrations of chromium were not

found in the vegetables Lady’s finger

(Hibiscus rsculentis) and Radish

(Raphanus sativus) irrigated with fresh

water (Fig. 5).

Fig. 5. Chromium (mg/Kg)

Lead (Pb): The level of Pb concentrations

in the vegetables irrigated with sewage

water was found in the range of 0.48 -

4.23mg/kg. The concentration of lead was

observed in the range of 0.27 - 2.87 mg/kg

in the vegetable samples irrigated with

fresh water. The concentration of lead was

determined higher in the fenu-greek

(Trigonella foenum - graecum) irrigated

with fresh water as compared to that

irrigated with sewage water because it was

grown near the road side (Fig. 6).

Fig. 6. Lead (mg/Kg)

Cadmium (Cd): It was noted that most of

the vegetables contained higher

concentrations of cadmium in the

vegetables irrigated with sewage water

than those irrigated with fresh water. The

level of cadmium in the vegetables

irrigated with sewage water was found in

the range of 0.04 - 1.86 mg/kg. The highest

concentration of cadmium was determined

1.86 mg/kg in the Couliflower (Brassica

oleracea) irrigated sewage water grew in

the field of Francisabad, Gujranwala near

the drain stream containing industrial and

domestic effluents. The concentrations of

cadmium were determined to be 0.01 -

0.34 mg/kg in the vegetables irrigated with

fresh water (Fig. 7).

Fig. 7. Cadmium (mg/Kg)

Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava

Volume XVII, Issue 1 – 2018

Table1.

Concentration of metals in edible part of vegetables irrigated by sewage/ fresh (tube well) water

Sampl

e No.

Vegetable

name

Botanical

name

Mn Zn Cu Fe Cr Pb Cd

mg/K

1 1SW Lady’s

finger

Hibiscus

esculentis

34.46 8.34 14.53 120 0.09 2.34 0.36

2 1FW Lady’s

finger

Hibiscus

esculentis

40.24 5.86 9.8 84 ND* 1.78 0.08

3 2SW Mint Mentha

Spicata

58.26 23.26 16.25 247 0.92 4.23 0.06

4 2FW Mint Mentha

Spicata

42.48 10.67 12.61 188 0.46 2.87 ND*

5 3SW Fenu-
Greek

Trigonella
foenum-

graecum

26.73 8.92 26.57 435 1.64 0.8 0.62

6 3FW Fenu-

Greek

Trigonella

foenum-

graecum

23.98 6.44 14.73 421 0.52 1.26 0.03

7 4SW Spinach Spinacia

oleracea

94.53 16.23 20.44 584 2.3 2.48 0.68

8 4FW Spinach Spinacia

oleracea

78.78 9.45 16.84 408 1.06 1.24 0.06

9 5SW Bell pepper Capsicum

annuum

38.51 20.53 13.52 133 0.26 3.21 0.04

10 5FW Bell pepper Capsicum
annuum

29.76 14.28 12.78 141 0.35 2.08 ND*

11 6SW Cauliflowe

Brassica

oleracea

32.13 12.79 19.63 98 1.8 0.94 1.86

12 6FW Cauliflowe

Brassica

oleracea

30.42 10.33 15.32 98 0.98 0.57 0.34

13 7SW Radish Raphanus

sativus

24.55 8.82 10.27 161 0.36 2.86 0.05

14 7FW Radish Raphanus

sativus

18.98 8.82 11.62 30 ND* 2.04 0.02

15 8SW Bitter

Gourd

Momordica

charantia

75.84 22.84 22.34 61 2.16 0.48 0.22

16 8FW Bitter

Gourd

Momordica

charantia

57.47 16.45 14 54 1.34 0.27 0.22

17 9SW Vegetable

Marrow

Cucurbita

pepo

35.65 9.82 8.86 48 0.42 2.24 0.04

18 9FW Vegetable

Marrow

Cucurbita

pepo

27.94 4.28 8.22 34 0.17 1.91 0.01

19 10SW Apple

Gourd

Praecitrullu

s fistulosus

10.34 10.44 9.58 72 1.42 2.53 0.94

20 10FW Apple

Gourd

Praecitrullu

s fistulosus

8.75 5.33 5.8 55 0.87 1.94 0.28

ND*= Not Dectected

4. Conclusion

Sewage water irrigation is practicing in

various developing countries like Pakistan

and normally considers a source of good

production. This study shows that

concentrations of micronutrients (Mn, Zn,

Cu, Fe and Cr) and toxic metals (Pb and

Cd) in edible parts of the vegetables were

higher in vegetables irrigated by sewage

Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava

Volume XVII, Issue 1 – 2018

water so using the sewage water as

irrigation source is hazardous to humans

health.

5. Acknowledgments

We are thankful to Dr. Izhar ul Haq

(Minhaj University Lahore) and Dr.

Muhammad Adnan Iqbal (University of

Agriculture Faisalabad) for their support

and guidance.

6. References

[1]. SNYDER R. L. and MELO-ABREU J. P.,
Frost protection fundamentals practice and

economics, Vol. 1, Food and Agriculture

Organization of the United Nations, (2005).

[2]. SIEBERT S., JIPPE H., PETRA D., JEAN-
MARC F., SEBASTIAN F., and KAREN F., The

Digital Global Map of Irrigation Areas–
Development and Validation of Map Version 4,

Tropentag, Conference on International

Agricultural Research for Development. University

of Bonn, (2006).

[3]. EMSLEY J., Manganese, Nature's Building
Blocks: An A-Z Guide to the Elements. Oxford,

UK: Oxford University Press, 249-253 (2001).

[4]. BROADLEY M. R., WHITE P. J.,
HAMMOND J. P., ZELKO I., LUX A., Zinc in

plants. New Phytologist, 173(4): 677-702, (2007).

[5]. FABRIS N., MOCCHEGIANI E., Zinc-
human diseases and aging. Aging clinical and
Experimental Research, 7: 77-93, (1995).

[6]. CHENEY K., GUMBINER C., BENSON B.,
TENENBEIN M., Survival after a severe iron

poisoning treated with intermittent infusions of

deferoxamine. Journal of Toxicology: Clinical

Toxicology. 33(1): 61-6, (1995).

[7]. ANDERSON R. A., Chromium as an
Essential Nutrient for Humans. Regulatory

Toxicology and Pharmacology, 26 (1 Pt 2): S35-

S41, (1997).

[8]. WISE S. S., WISE JP. SR., Chromium and
Genomic stability. Mutation Research
/Fundamental and Molecular Mechanisms of

Mutagenesis, 733(1-2): 78-82, (2012).

[9]. ABRAHAM M. R., COLIN D. R.,
MARGARET K. H., GEORGE E. L., NORMAN J.

S., Lead. Rudolph's Pediatrics (21st ed.) McGraw-

Hill Professional, 369 (2003).

[10]. JULIN B., WOLK A., JOHANSSON J. E.,
ANDERSSON S. O., ANDREN O., AKESSON A.,

Dietary cadmium exposure and prostate cancer

incidence: A population-based prospective cohort

study. British Journal of Cancer, 107(5): 895-900,

(2012).

[11]. ENGSTROM A., MICHAELSSON K.,
VANTER M., JULIN B., WOLK A., AKESSON

A., Associations between dietary cadmium

exposure and bone mineral density and risk of

osteoporosis and fractures among women. Bone.

50(6): 1372-1378, (2012).

[12]. JULIN B., WOLK A., BERGKVIST L.,
BOTTAI M., AKESSON A., Dietary cadmium

exposure and risk of postmenopausal breast cancer:

A population-based prospective cohort study.

Cancer Research. 72(6): 1459-1466, (2012).
[13]. Agency for toxic substances and disease
registry. Toxicological profile for chromium. U.S.

Public health service, Department of Health and

Human Services, Atlanta, US, (1998).

[14]. AMMA M. K., Plant and Soil Analysis.
Rubber Research Institute, Rubber Board,

Kottayam-686009, Keral, (1990).

[15]. JONES J., Benton, Plant tissue analysis for
micronutrients, In J. J. Mortvedt et al., (ed)

Micronutrients in Agriculture. Soil Science Society

America, Madison, Wisconsin, U.S.A., 319-348,
(1972).

[16]. RECHARDS L. A., Diagnosis and
Improvement of Saline and Alkali soils. (ed) 1954,

Oxford and IBH Publishing Company, New Delhi,

(1968).

https://books.google.com/?id=j-Xu07p3cKwC
https://books.google.com/?id=j-Xu07p3cKwC
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4138963
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4138963
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3425979
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3425979
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3425979

1. Introduction
4. Conclusion