Archives of

1. Introduction
ereals, especially wheat, rice, and barley
are among the main products and an integral
part of the human diet. They play
a vital role in human growth by providing
carbohydrates, proteins, minerals, and
micronutrients [1]. Consumption of wheat
grains and other grains is safe when the accumulation
of metals is within the permissible limits [2]. Khuzestan
Province in Iran has long had many opportunities in the
agricultural sector. Geographical features (fertile soil,
abundance of permanent and seasonal rivers, water and
land roads, etc.) have made this province one of the agricultural
hubs of Iran [3]. The resistance and stability
of heavy elements in the soil are much longer than other
contaminants, and soil contamination by heavy metals is
almost permanent [4]. Iron and steel industries, mining,
road transport, power plants, and waste incineration are
among the causes of heavy metals entering soil and water
in surface ecosystems [5-7].
Generally, as the concentration of heavy metals in the
soil increases, the amount of bioavailability of these elements
increases [8]. Excessive absorption of these elements
by plants and entering the food chain threatens
human health [9-12]. These metals in high amounts can
cause morphological disorders, growth retardation, increased
mortality, and genetic effects in humans [13, 14].
In Iran, 50% of the most common cancers are related to
the gastrointestinal tract, of which gastric cancer is more
common. Research has shown that environmental pollution
(from industrial areas or agricultural fertilizers) and
heavy metals in the environment and the food chain can
be among the most influential and essential factors in
causing this type of cancer [3, 5].
Prolonged consumption of foods with high concentrations
of heavy metals may increase the risk of disease in
humans [15]. However, when these metals are consumed
for a long time during their lifetime, they can have destructive
effects even in safe doses [16]. Therefore, to
assess the risk of a particular element, the period of consumption
should also be considered [17].
Khuzestan Province has a high potential for the production
of diverse, strategic, and industrial crops. However,
the province is affected by many industrial activities
such as refineries, petrochemicals, steel industries,
sugarcane factories, oil and gas companies, and improper
use of fertilizers, pesticides, and unhealthy irrigation.
Thus, these issues double the importance of this study
[18]. Accordingly, the main purpose of this study was
to determine the level of heavy metal contamination of
chromium, nickel, arsenic, copper, zinc, cadmium, and
lead in barley grains grown in Khuzestan Province and
to assess the health risk of their consumption in the age
groups of adults and children.
2. Materials and Methods
Study area
Khuzestan Pr o vince, with an area of 64236 km2 is
located between the latitudes of 29° 57› and 33° 0› N
and between the longitudes of 47° 40› and 50° 33› E
of the Gree n wich meridian in southwestern Iran. The
province›s total population is 4710509 people, equivalent
to 5.8 9 % of the country›s population. The geographical
location of the study area is shown in Figure 1.
Karun river, as the largest river in Iran, passing through
large areas of Khuzestan Province, has contributed significantly
to the region›s agriculture. However, along the
way, the river is closely related to a group of the most
important industries such as metallurgy, petrochemicals,
and oil and is also in contact with an essential part of municipal
and agricultural wastewater. So the presence of
any metal elements, especially heavy metals, in wastewater
to this river can be considered a potential cause of
pollution and danger [19].
Study sampling
The present study is an analytical study. In the present
study, to estimate the risk of barley consumption in
Khuzestan Province, 40 farms in 10 cities of the province
were designated for sampling. These farms were selected
for barley from Hindijan, Hamidiyeh, Azadegan,
Shadegan, and Shushtar counties.
Selected cities are marked with an asterisk in Figure 1.
In each city, four farms were designated for sampling.
After selecting the farms, the sampling was done during
the barley harvest season in 2019. Considering a total of
5 areas, four stations in each area, and three replications,
we prepared 60 samples. The samples were placed in
polyethylene plastics and transported to the laboratory.
Analysis and preparation of samples
Barley samples were washed with distilled water and
dried in the air. Then, they were ground using a mill and
weighed 1 g of each with a digital scale and were reduced
to ashes at 550°C for 5 h. Plants containing barley
ash were placed in a desiccator to cool. In the next
step, 2.5 mL of 6.0M HNO3 was added to dissolve the
C
Fouladi M, et al. Health Risk Assessment of MH in Barley. Arch Hyg Sci. 2021; 10(2):163-170.
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Spring 2021. Volume 10. Number 2
samples [20]. All required test dishes were washed with
0.30 nitric acid, rinsed with deionized distilled water,
and dried in an oven [21]. The dissolved samples were
then passed through a paper filter and volumized in a 20-
mL flask. The resulting solution was analyzed by Inductively
Coupled Plasma–Mass Spectrometry (ICP-MS) to
determine the concentration of heavy metals in barley
samples [22]. The samples were analyzed in Zarazma
Mineral Studies Laboratory in Tehran. Data analysis was
performed using SPSS software, and graphs were drawn
using Excel software.
Product crop pollution index
Heavy metal contamination levels in crops are assessed
using the product pollution index (CPI). In this study,
CPI is obtained by dividing the concentration of heavy
metals determined in barley samples by the standard value
of each metal. The CPI is calculated from Equation 1.
Equation 1) CPI=
pi
Spi
In Equation 1, Pi represents the measured concentration
of element i in the plant, and Spi represents the standard
allowable value of each element in the plant seed. For this
purpose, we used the value of the standard proposed by
FAO/WHO and the Chinese national standard (because it
covers more complete elements than JECFA) [23].
Heavy metal health risk assessment
To assess exposure to heavy metals, we calculated the
estimated daily intake index (EDI, mg/kg/d) according
to Equation 2 provided by the US Environmental Protection
Agency.
Equation 2) EDI= Cmetal×EF×ED×IR
BW×TA
In Equation 2, EDI is the rate of chronic daily uptake
of heavy metals (mg/kg/d). Cmetal is the rate of concentration
of heavy metals in the crop consumed (mg/
kg). IR refers to the average daily consumption of barley
crops (g/d). ED denotes the exposure period (60 years
for adults and 12 years for children). EF is the exposure
frequency (365 days). TA refers to the mean exposure
time (days) multiplied by EF in ED (for non-carcinogenic
risk) and for carcinogenic risk (365 × 70 years).
Finally, BW is the average body weight in kg (15 kg for
children and 70 kg for adults) [28, 29].
The Hazard Quotient (HQ) indicates the potential noncarcinogenic
risk for each heavy metal. HQ is defined as
the EDI rate (mg/kg/d) to the reference dose (RfD, mg/
kg/d) and is an estimate of the daily exposure of the human
population that is improbable to indicate a high risk
of life-threatening side effects. The method of calculating
HQ is given in Equation 3.
Equation 3) HQ= EDI
RfD
Figure 1:
Figure 2:
Figure 1. Geographical Location of the Study Area
Fouladi M, et al. Health Risk Assessment of MH in Barley. Arch Hyg Sci. 2021; 10(2):163-170.
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Spring 2021. Volume 10. Number 2
In Equation 3, the RfD values for selected heavy metals
in different exposure pathways are determined by the US
Environmental Protection Agenc y (USEPA). According
to the assessment of the overall potential risk imposed by
more than one heavy metal, HQ can be added to generate a
hazard index to estimate the consolidated risk (Equation 4).
Equation 4) Hazard Index=Σn
n=1
EDIn
RfDn
Table 1. Statistical summary of studied heavy metal concentrations in barley grain and crop contamination index (CPI) for this
plant (N= 60)
Contamination Index in Crops (Barley) Cr Pb Cd As Cu Zn Ni
Average concentration of metals in barley (mg/kg) 0.03 0.29 0.059 0.031 4.29 18.46 0.36
Standard deviation of metal concentration 0.013 0.131 0.025 0.021 1.86 5.25 0.16
The least 0.01 0.06 <LOD <LOD 1.2 7.5 0.11
The most 0.057 0.63 0.1 0.09 8.3 28.3 0.69
World Food Safety Standard * (mg/kg) 0.02 0.2 0.1 0.126 4.7 24 0.34
Internal standard ** (mg/kg) - 0.15 0.06 0.15 - -
Average CPI for each metal in wheat grain 1.50 1.45 0.57 0.24 0.91 0.77 1.06
CPI standard deviation 0.62 0.59 0.24 0.13 0.37 0.22 0.41
Number of infected samples based on CPI index 33 42 0 0 27 6 26
Percentage of infected samples based on CPI (%) 55 70 0 0 45 10 43.3
* [24-26], **[27]
LOD for As: 0.005, Cu: 0.013.
Figure 1:
Figure 2:
Figure 2. Risk of each heavy metal in HQ for children and adults due to barley consumption over one year
Fouladi M, et al. Health Risk Assessment of MH in Barley. Arch Hyg Sci. 2021; 10(2):163-170.
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Spring 2021. Volume 10. Number 2
If the HI exceeds 1, there is a chance of non-carcinogenic
effects, and the probability increases with increasing
value. Otherwise, there is probably no non-carcinogenic
effect [30].
For carcinogens, the risk is estimated as an increased
likelihood of developing cancer in a person’s lifetime
due to exposure to potential carcinogens. Potential carcinogenic
risk can be assessed using Equation 5:
Equation 5) Cancer Risk=EDI×SF
In Equation 5, Cancer Risk (CR) is the risk of carcinogenic
risk (without dimensions). It refers to the total risk
of carcinogenic risk, and SF is the carcinogenic slope
factor of each metal (1/mg/kg/d). The overall risk of
carcinogenicity is equal to the total risk of all exposure
pathways due to all individual metals. The SF values for
selected heavy metals at different exposure paths are determined
by USEPA. The permissible total risk range for
legislative purposes is 10-⁶ to 10-⁴. Typically, a CR less
than or equal to 10-⁶ indicates relatively effective immunity,
and a CR equal to or greater than 10-⁴ indicates a
potentially high carcinogenic risk.
3. Results
According to Table 1, the amounts of heavy metals in
the studied atmosphere in the five regions of the province
are ascending and as follows:
Zn (5.25±18.46) Cu>(4.29±1.86) >Ni (0.36±0.16)
Pb>(0.29±0.131)>Cd (0.059±0.025)> As(0.031±0.021)>
Cr (0.03±0.13)
The highest concentration is related to zinc, and the
lowest to chromium. According to the crop contamination
index, the number of infected samples and the corresponding
percentage of each are presented in Table 1.
Equation 3 was used to calculate the non-cancer risk
of the studied elements for one year. HQ is divided into
two age groups of adults and children in 40 stations of 10
study areas and is shown in Figure 2. The non-carcinogenic
risk classification of heavy metals was performed
by the US Environmental Protection Agency [31].
According to the USEPA classification, arsenic belongs
to group A carcinogens, and the IARC has also introduced
cadmium as a carcinogen. The carcinogenic risk
of these two elements was calculated with Equation 5 in
different regions, and the results are presented in Table 2
separately for adults and children.
4. Discussion
As mentioned in Table 1, the lowest CPI belonged to
arsenic (0.24±0.13) mg/kg and the highest to chromium
(1.50±0.62) mg/kg. According to Table 1, 10%, 43.3%,
45%, 55%, and 70% of the barley samples for zinc,
nickel, copper, chromium, and lead were above the standard,
respectively. In the case of cadmium and arsenic,
no sample exceeded the standard [32].
According to the study results, in the Ahvaz region, HQ
values of cadmium, arsenic, and copper for children are
above 1 and at level 3 (medium) chronic risk (chronic). The
non-carcinogenic health risk of heavy elements in children
increases significantly due to the increase in the intake of
the element relative to their body weight [17, 33, 34].
Figure 2 shows the degree of involvement of each
heavy element affecting the HQ index for children and
adults in each of the five regions (in the case of barley
species) separately. In Hindijan, Hamidiyeh, and
DashteAzadegan, copper, and cadmium have the highest
impact on the potential non-carcinogenic risk index in
both children and adults. In Shadegan and Shushtar regions,
Lead, arsenic, and cadmium have played the most
crucial role in increasing the HQ.
According to Table 2, the carcinogenic risk by consuming
barley in the study areas for adults was average
and for children was low. Therefore, the consumption of
barley in the study areas has little effect on increasing
the risk of cancer. Findings of this study were consistent
with the research of Djahed et al. in Iranshahr [22], Doabi
et al. in Kermanshah [24], Rezapour et al. in West
Table 2. Carcinogenic Hazards (CR) of heavy metals (Arsenic and Cadmium) due to barley consumption for adults and children
Content Risk at Carcinogenicity of Children Risk at Adult Carcinogenesis
Heavy metals
study stations Cancer risk (Cd) Cancer risk (As) Cancer risk (Cd) Cancer risk (As)
Mean (CR) of the whole area in
the case of barley: 2.8×10-⁶ 6.04×10-⁶ 2.2×10-⁶ 4.6×10-⁶
Fouladi M, et al. Health Risk Assessment of MH in Barley. Arch Hyg Sci. 2021; 10(2):163-170.
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Azerbaijan Province [33] in Iran, and other similar studies
on the higher risk of carcinogenicity in children compared
to adults [35, 36].
5. Conclusion
In areas with high heavy metal content in the soil and
high enrichment coefficients (heavy enrichment coefficients)
of heavy metals, we can reduce the potential
harm to human health by controlling the source of contamination,
adjusting cropping practices, setting planting
patterns, proper use of fertilizers or even reduce land use
change. The presence of nickel and chromium in agricultural
soils may be due to anthropogenic resources such as
fertilizer application, precipitation due to vehicle traffic,
and industrial activities [37]. Chromium and cadmium in
agricultural soils may be due to the use of wastewater for
field irrigation [38]. On the other hand, the association
of nickel with copper in agricultural soils is often due to
the use of municipal wastewater for irrigation [39]. The
presence of copper and arsenic in the first component
reflects the industrial activities or direct use of pesticides
for products, which is mainly related to the use of pesticides
and fungicides [40]. Copper is considered an indicator
of agricultural activities that are specifically related
to commercial fertilizers [37].
In this study, the risks of barley consumption (HQ
and CR) for children were much higher than for adults.
This finding indicates that children are more sensitive to
consuming foods contaminated with heavy metals than
adults. According to the USEPA assessment, the average
Risk of Carcinogenicity (CR) in the province’s barley
consumption for arsenic is 4 adults per million (low-risk
level 2) and 6 children per million (low-risk level 2), and
for cadmium, it was estimated at 2 adults per million
(low-risk level 2) and 3 children per million (low-risk
level 2) in the population of the province, which means
that the consumption of barley in Khuzestan Province in
the study areas is not endangered during the long life of
the consumer.
Ethical Considerations
Compliance with ethical guidelines
This article is a meta-analysis with no human or animal
sample.
Funding
This article was extracted from the PhD. dissertation of
the first author at the Department of Environment, Ahvaz
Branch, Islamic Azad University, Ahvaz (Research
Council Code: 106484131980721162301978).
Authors' contributions
Methodology: Maryam Mohammadi Rouzbahani;
Software, Validation, Formal Analysis: Sina Attar Roshan;
Writing – Original Draft Preparation:Masoumeh
Fouladi; Writing – Review & Editing: All outhors.
Conflict of interest
The authors declared no conflict of interest.
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