Heavy metals in fish, fruits and vegetables from Rajshahi, Bangladesh: A statistical approach

Abstract

Vegetables, fruits, and fishes are the main routes of exposure to heavy metals for most of the Bangladeshi population.
Thus, the present study was conducted to determine the content of lead (Pb), manganese (Mn), chromium, (Cr), cadmium (Cd), and arsenic (As) in some key vegetables, fruits, and fishes purchased from the city market of Rajshahi using atomic absorption spectrometry.
The Pb, Mn, Cr, Cd, and As concentrations ranged from 0.42 to 23.99, 1.13 to 8.11, 0.17 to 2.50, 0.15 to 3.02, and 0.07 to 0.15 mg/kg dry weight respectively. The estimated amounts of heavy metals were lower than the recommended values, but considerable attention should be paid to the Pb and Cd concentrations. Especially, among five heavy metals in three food categories, fish samples were highly contaminated by Pb. The results revealed that the estimated daily intakes of heavy metals were within the respective recommended daily dietary allowance established internationally. The biggest contribution of daily intakes of heavy metals came from the vegetables, which could be due to its high consumption rate.
Results of one way ANOVA test demonstrated that heavy metal concentrations were statistically significant (p < 0.05) among the different vegetable, fruit, and fish species. Furthermore, no significant correlation was found between the heavy metals in vegetables, fruits, and fishes except Pb-Cd (r = 0.899, α = 0.05) in fruits.

Full text

Journal of Nature Science and Sustainable Technology ISSN: 1939-0324
Volume 6, Number 3 © 2012 Nova Science Publishers, Inc.
HEAVY METALS IN FISH, FRUITS AND VEGETABLES
FROM RAJSHAHI, BANGLADESH:
A STATISTICAL APPROACH
Narottam Saha1

, M. R. Zaman1 and M. Safiur Rahman2
1Environmental and Tracer Studies Laboratory,
Department of Applied Chemistry and Chemical Engineering,
Faculty of Engineering, University of Rajshahi,
Rajshahi, Bangladesh
2Department of Environmental Engineering, Faculty of Engineering,
Dalhousie University, Halifax, Nova Scotia, Canada
ABSTRACT
Vegetables, fruits, and fishes are the main routes of exposure to heavy metals for
most of the Bangladeshi population.
Thus, the present study was conducted to determine the content of lead (Pb),
manganese (Mn), chromium, (Cr), cadmium (Cd), and arsenic (As) in some key
vegetables, fruits, and fishes purchased from the city market of Rajshahi using atomic
absorption spectrometry.
The Pb, Mn, Cr, Cd, and As concentrations ranged from 0.42 to 23.99, 1.13 to 8.11,
0.17 to 2.50, 0.15 to 3.02, and 0.07 to 0.15 mg/kg dry weight respectively. The estimated
amounts of heavy metals were lower than the recommended values, but considerable
attention should be paid to the Pb and Cd concentrations. Especially, among five heavy
metals in three food categories, fish samples were highly contaminated by Pb. The results
revealed that the estimated daily intakes of heavy metals were within the respective
recommended daily dietary allowance established internationally. The biggest
contribution of daily intakes of heavy metals came from the vegetables, which could be
due to its high consumption rate.
Results of one way ANOVA test demonstrated that heavy metal concentrations were
statistically significant (p < 0.05) among the different vegetable, fruit, and fish species.
Furthermore, no significant correlation was found between the heavy metals in
vegetables, fruits, and fishes except Pb-Cd (r = 0.899, α = 0.05) in fruits.
Keywords: Heavy metals, foodstuff, food contamination, dietary intake
 Corresponding Author: narottam.saha@yahoo.com

Narottam Saha, M. R. Zaman and M. Safiur Rahman
238
1. INTRODUCTION
During the last decades healthy eating habits have received increased attention.
Vegetables, fishes, and fruites are important components of human diet and it is well-known
that consumption of these food items on a regular basis is one of the possible health
improving practices. However, except occupational exposures at related industries, diet is the
main route of human exposure to heavy metals, which are one of the potential hazards
associated with foodstuffs (Marti-cid et al., 2008). Consequently, the levels of metals in basic
foodstuffs are of great interest from the toxicological and nutritional point of view. Natural
and anthropogenic activities, for example, solid-waste disposal, atmospheric deposition, and
the application of sewage sludge and waste water irrigation on land are the main sources of
heavy metal contamination in the environment (Cui et al., 2005). The use of agrochemicals
such as fertilizers and metal-based pesticides play an important role in the contamination of
foodstuffs by heavy metals, especially in the developing countries where the use of
agrochemicals is not well controlled. Heavy metals are stable and persistent environmental
contaminants. Heavy metals present in the environment in minute quantities become part of
various food chains through biomagnification and their concentration increases to such a level
that may prove to be toxic to both humans and other living organisms. Prolonged
consumption of foodstuffs enriched with heavy metals may lead to the chronic accumulation
of metals in the kidney and liver of humans causing disruption of numerous biochemical
processes, leading to cardiovascular, nervous, kidney, and bone diseases (Banerjee et al.,
2010). Some heavy metals such as cadmium (Cd) and arsenic (As) are considered to be
carcinogenic (Feig et al., 1994), Hg and Pb are associated with the development of
abnormalities in children (Gibbes and Chen, 1989). while some others heavy metals such as
copper (Cu), zinc (Zn), chromium (Cr), manganese (Mn) lie in the narrow “window” between
their essentiality and toxicity, i.e., they are nutritionally essential at lower levels but can also
be toxic when certain limits are exceeded (Loutfy et al., 2012). The toxic effect of metals can
change according to the characteristics of metals. Generally, heavy metals create toxic effect
by forming complexes with organic compounds (Akbulut et al., 2011).
It is very important to have reliable database on contamination levels in commonly
consumed foodstuffs for elucidating the present status of heavy metal contamination and to
ensure food safety. Monitoring and assessment of heavy metals in foodstuffs from market
sites have been carried out in some developed (Milacic and Kralj, 2003; Marti-Cid et al.,
2008) and developing countries (Loutfy et al., 2012; Radwan and Salama, 2006; Al Jassir et
al., 2005; Santos et al., 2006; Sharma et al., 2008). It is reported that Bangladeshi foodstuffs
showed relatively high concentration of heavy metals grown in different regions of
Bangladesh (Alam et al., 2003). No data, however, are presently available regarding the status
of heavy metals in foodstuffs commonly consumed by the population of Rajshahi city, the
biggest city in northern Bangladesh (Figure 1). Bangladesh extends between longitudes
88o01´ and 92o40´ east and latitudes 20o25´ and 26o38´ north. Geographically, Bangladesh
consists of the great flood plain of the Bengal Delta bordered by the Himalaya– Arakan–
Yoma mountain range complex in the north and east.
This investigation was initiated with the following objectives (i) to monitor the levels of
selected heavy metals Pb, Mn, Cr, Cd, and As in the vegetables, fruits, and fishes, purchased
from Shaheb Bazar (central market) of Rajshahi City, Bangladesh, (ii) to estimate the dietary

Heavy Metals in Fish, Fruits and Vegetables from Rajshahi, Bangladesh
239
intake exposure for adults through the consumption of these food commodities, and (iii)
lastly, to evaluate the potential health risks by comparing the estimated daily dietary intake
with the appropriate safe intake levels.
Figure 1. Study area (Shaheb Bazar), Rajshahi District, Bangladesh.

Narottam Saha, M. R. Zaman and M. Safiur Rahman
240
2. MATERIALS AND METHODS
2.1. Sample Collection
Fresh vegetables, fruits, and fish samples were purchased in triplicate from Shaheb Bazar
(Figure 1) monthly from June 2010 to August 2010 in required amounts and rapped in
polyethylene bags to transport to the laboratory.
These food items were grown in different parts of the suburban city such as Khorkhori,
Mohongonj, Tanor, Godagari, Bagmara, Nowhata, Puttia, Banaeshor, Porsa etc and
transported to the city market for public consumption. The details of different foodstuffs
sampled during the experiment were given in Table 1.
Table 1. Samples with their local, English, scientific and family name
Category
Local name
(Bangla)
English name
Scientific name
Family
Vegetable
Alu
Potato
Citrullus lanatus
Cucurbitaceae
Potol
Pointed gourd
Trichosanthes dioica
Cucurbitaceae
Korola
Bitter gourd
Momordica charamtia
Cucurbitaceae
Dherosh
Okra
Abelmoschus esculentus
Malvaceae
Kakrol
Tesla gourd
Momordica
cochinchinensis
Cucurbitaceae
Misti Kumra
Sweet gourd
Cucurbita maxima
Cucurbitaceae
Begoon
Brinjal
Solanum melongena
Solanaceae
Lalshak
Red amaranth
Amaranthus gangeticus
Amaranthaceae
Payaj
Onion
Allium cepa
Lilliaceae
Mula
Radish
Raphanus sativus
Cruciferae
Fruit
Kalojam
Black berry
Syzygium cumini
Rosaceae
Am
Mango
Mangifera indica
Anacardiaceae
Payara
Guava
Psidium guajava
Myrtaceae
Kala
Banana
Musa sapientum
Musaceae
Litchi
Litchi
Litchi chinensis
Sapindaceae
Fish
Tilapia
Mozambique
tilapia
Oreochromis mossambicus
Cichlidae
Rui
Rohu
Labeo rohita
Cyprinidae
Ilish
Hilsa shad
Tenualosa ilisha
Clupeidae
Katol
Catla
Catla catla
Cyprinidae
Boal
Wallago
Wallago attu
Siluridae
2.2. Sample Pretreatment
The samples were thoroughly cleaned, first under tap water to eliminate dust, dirt,
possible parasites or the eggs and then washed again with double distilled water (DDW).
Non-edible parts were removed according to common household practices and the edible
portion was chopped into small pieces. The small pieces of samples were air dried to remove

Heavy Metals in Fish, Fruits and Vegetables from Rajshahi, Bangladesh
241
the extra water and then dried in an oven at 80oC until a constant weight was obtained. The
dried samples were crushed using mortar and pestle and passed through a 100-mesh sieve.
The resulting fine powder was stored in airtight plastic vials inside desiccators until digestion.
2.3. Analytical Procedure
One gm of each vegetable samples were taken into the 250 ml digestion vessel. 15 ml of
tri-acid mixture (concentrated HNO3, HClO4, H2SO4; 5:1:1) was added to the vessel and
heated at 80oC till the solution became transparent (Sharma et al., 2007; Sharma et al., 2008;
Gupta et al., 2008). The digested vegetable samples were cooled and filtered through the
Whatman No. 42 filter paper and the filtrates were diluted to 50 ml with double distilled
water.
One gram of dried powder of each fruit and fish sample was digested in a 250 ml
digestion vessel by adding 10 ml of HNO3 (65%) and 2 ml of H2O2 (30%) at 80oC until a
clear solution was appeared and then filtered (Whatman No. 42) on cooling. Final volume
was made in a 50 ml volumetric flask with double distilled water (Zaman et al., 2010).
Table 2. Standard working conditions for Shimadzu AA-6800 atomic absorption
spectrophotometer
Element
Wave length
(nm)
Slit width
(nm)
Lamp current
(mA)
Atomizer
Detection limit
(mg/L)
Pb
283.3
0.5
10
Flame
0.04
Mn
285.2
0.5
8
Flame
0.02
Cr
357.9
0.5
10
Flame
0.01
Cd
228.8
0.5
8
Flame
0.006
As
193.7
1.0
12
Graphite
furnace
0.001
The concentrations of Pb, Mn, Cr, Cd, and As in all digested solutions were determined
by an atomic absorption spectrophotometer (model AA-6800, Shimadzu Corporation, Japan).
The instrument was fitted with specific lamp of particular metal.
Calibration of the instrument was performed using manually prepared standard solution
of respective heavy metals as well as drift blank. Standard stock solutions of 1000 ppm for all
the heavy metals were obtained from Kanto Chemical Co. Inc, Tokyo, Japan. These solutions
were diluted for desired concentrations to calibrate the instrument. Acetylene gas was used as
the fuel and air as the support. Standard working conditions for Shimadzu AA-6800 atomic
absorption spectrophotometer were tabulated in Table 2. The results were expressed as mg/kg
or ppm of dry weight.
2.4. Statistical Analysis
Duplicate analyses were performed for each sample and the duplicate tests were
statistically similar in paired-samples t-test, at 95% significance level. Variations in the
concentration of analysed heavy metals with respect to various vegetable samples, different

Narottam Saha, M. R. Zaman and M. Safiur Rahman
242
fruit samples, and different fish species were analysed using one way analysis of variance
(ANOVA) test. The significance of differences in heavy metal concentrations amongst
foodstuffs of three different categories (vegetable, fruit, and fish) were also tested with one
way ANOVA. Possibilities less than 0.05 were considered statistically significant (p < 0.05).
Data were processed using Microsoft Excel 2010 and the Statistical Package for Social
Science (SPSS 15.0 for Windows).
3. RESULTS AND DISCUSSION
3.1. Concentrations of Pb, Mn, Cr, Cd, and As in Foodstuffs
Heavy metals are the major contaminants of food supply that affect the nutritive values of
vegetables, fruits, and fishes, and eventually pose deleterious effects to human population.
National and international regulations on food quality have lowered the maximum
permissible levels of toxic heavy metals in human diet. Therefore, increasing attention should
be paid to control the food quality in terms of heavy metals.
The mean concentrations and range of Pb, Mn, Cr, Cd, and As measured in vegetables,
fruits, and fishes studied were given in Table 3. The concentrations of heavy metals were
determined based on sample dry weight. The metal concentrations showed variations among
different vegetable/fruit/fish collected from Shaheb Bazar as shown in Figure 2. The observed
variation in heavy metal concentrations for all types of analyzed foodstuffs could be due to
variable capabilities of absorption and accumulation of heavy metals (Pandey and Pandey,
2009), variations in growth period and growth rates (Moseholm et al., 1992), climatic
differences of the producing areas (Santos et al., 2006). The order of the levels of heavy
metals obtained from different kinds of vegetables, fruits, and fishes were Pb> Mn> Cr> Cd>
As, Mn> Cd> Cr> Pb> As, Pb> Mn> Cd> Cr> As respectively. Arsenic (As) was the least
available heavy metal in three examined food categories.
3.1.1. Levels of Lead
The results (Table 3 and Figure 2) revealed that the concentrations of lead varied from
1.37 mg/kg (Potato) to 10.43 mg/kg (Sweet gourd and Radish) in vegetables, 0.42 mg/kg
(Banana) to 1.45 mg/kg (Mango) in fruits and 1.44 mg/kg (Mozambique tilapia) to 23.99
mg/kg (Catla) in fishes. The EU Commission Regulation (European Union, 2006) and the
Codex Alimentarius Commission (2001, 2004) set the maximum level (ML) of 0.3 mg /kg
FW for brassicas, leafy vegetables and herbs, and 0.1 mg /kg FW for all remaining vegetables
and fruits.
In Australia and New Zealand, the ML of Pb set by the Australian and New Zealand
Food Authority (ANZFA) (ANSTAT, 2001) is 0.1 mg /kg FW for all vegetable types
excluding Brassicas (0.3 mg /kg FW). Mean Pb content in vegetables was higher than the
recommended limit, whereas mean fruits Pb content was lower than this prescribed limit
(considering 79% moisture content). Another study reported a maximum allowable level of
0.01 mg of Pb/kg based on fresh weight (Al-Chaarani et al., 2009). As lead (Pb) is not being
translocated readily in plants, it could be suggested that Pb found in different vegetable and
fruit samples were originated from atmospheric deposition.

Heavy Metals in Fish, Fruits and Vegetables from Rajshahi, Bangladesh
243
Table 3. The range and mean concentrations (mg/kg) of heavy metals in vegetables,
fruits, and fishes
Heavy metals
Vegetable
Fruit
Fish
Range
Mean
Range
Mean
Range
Mean
Pb
1.37-0.43
5.10
0.42-1.45
0.97
1.44-23.99
15.55
Mn
1.36-8.11
4.54
2.01-5.09
3.22
1.13-5.22
3.27
Cr
0.17-1.93
1.07
0.51-2.50
1.16
0.42-1.23
0.70
Cd
0.15-1.75
1.05
0.58-3.02
1.57
0.22-2.11
1.36
As
0.07-0.15
0.11
0.09-0.13
0.17
0.10-0.15
0.13
Figure 2. Mean and maximum concentration of heavy metals in foodstuffs.
Vehicular Pb emission could also be likely source of lead pollution in areas close to
agricultural field, especially in developing countries. The concentrations Pb in vegetables
(1.37-10.43 mg/kg) were several folds lower than those were reported in West Bengal, India

Narottam Saha, M. R. Zaman and M. Safiur Rahman
244
(21.59-57.63 mg/kg) (Gupta et al., 2008); in Gujranwala city, Pakistan (15.75-22.5 mg/kg)
(Khan et al., 2003) and the mean concentration of Pb (409 mg/kg) found in Turkey by
Turkdogan et al. (2002). However, present results were similar to the findings of Liu et al.
(2006) in China (0.18-7.75 mg/kg); Liu et al. (2005) (1.97-3.81 mg/kg); Sharma et al. (2007)
in Varanasi, India (3.09-15.74 mg/kg) and Demirezen et al. (2006) in Kayseri,Turkey (3.3-
10.7 mg/kg). The observed levels of Pb in fruits were comparable with the values (0.01-2.19
mg/kg) in seasonal fruits of Pakistan reported by Jaffar et al. (2003). Tripathi et al. (1997)
(Bombay city, India) found the mean concentration of 7.4 µg of Pb/kg in fruits. The European
maximum permitted concentration (MPC) (European Union, 2006) of Pb established for fish
muscle is 1.44 mg/kg DW (considering 79% moisture content). Catla exhibited highest Pb
concentration (23.99 mg/kg) followed by Hilsa shad (21.31 mg/kg), Wallago (16.46 mg/kg),
Rohu (14.57 mg/kg), and Mozambique tilapia (1.44 mg/kg). Our study revealed that all
examined fish samples exceeded the recommend level for human consumption. The high
contamination of fish samples could be due to the agricultural runoff and for discharging
domestic sewage into the nearby rivers and ponds. The concentration of Pb in fishes from
central market of Rajshahi city was higher than the fishes from Saudi market (244-22 ng/g)
(Al-Bader, 2008); the edible carnivorous fishes from Arabian Sea (0.01±0.02 - 0.41±0.02
µg/g) (Azmat et al. 2006), and the mean Pb concentration (2.08 µg/g) recorded in the muscle
tissue of three species of fish from the fresh water Dhanmondi Lake, Bangladesh (Begum et
al., 2005). Saudi Arabia set maximum limits of lead in fish and shellfish of 2 µg/g (SASO,
1997).
3.1.2. Levels of Manganese
Manganese is an essential metal for proper body function. But it is toxic at quite high
concentration. Mn contents for vegetables were recorded between 1.36 to 8.11 mg/kg (in
Sweet gourd and Onion respectively), for fruits between 2.01 to 5.09mg/kg (in Blackberry
and Banana respectively), and for fishes between 1.13 to 5.22 mg/kg (in Catla and Rohu
accordingly) (Table 3 and Figure 2). No maximum is specified for Mn in foodstuffs. Many
researchers reported the Mn concentration in vegetables. In our study, the level of
contamination was several times lower than the vegetables that had been reported by Khan et
al. (1989) (5.99 to 72.6 mg/kg). Manganese level in vegetables from industrial area of
Thessaloniki, N. Greece was (1.86 to 66 µg/g) (Voutsa, 1996); from Challawa industrial area,
Kano State, Nigeria was (1.00-6.00 μg /g) in tomato while cabbage had the least
concentrations (0.22-1.22 μg/ g) (Akan et al., 2009). In this study, the mean Mn level of 3.22
mg/kg was measured in fruits from central city market, Rajshahi. Zahir et al. (2009) measured
the Mn content of 0.05 mg/kg and 0.037 mg/kg in Mango and Banana respectively from
Karachi city markets (Pakistan), which were lower than our values. On the contrary, the
reported values of Mn in Mango and Banana by Mahdavian et al. (2008) were several folds
higher than our value.
Manganese content in the examined samples was lower than that was reported by Mendil
et al. (2005) in lakes in Tokat, Turkey (11.1 to 72.9 µg/g); by Begum et al. (2005) in
Dhamondi Lake, Bangladesh (8.8 to 23.5 µg/g). In terms of Mn in fish, it was recorded from
0.59 to 11.74µg/g in Lake Tanganyika, Tanzania (Chale et al., 2002); (0.78 to 2.27 µg/g) in
the Kola Region, Russia (Moiseenko et al., 2001); (0.25 to 12.38 mg/kg) in frozen and canned
marine fish of Korea (Islam et al., 2010).

Heavy Metals in Fish, Fruits and Vegetables from Rajshahi, Bangladesh
245
3.1.3. Levels of Chromium
Chromium is usually found in its trivalent forms (Cr+3) in biological and food samples,
although it can be found in hexavalent form (Cr+6), which is toxic. Cr+3 is necessary for
insulin activity. The maximum concentration of Cr was 1.93 mg/kg (Red amaranth) and the
minimum was 0.17 mg/kg (Sweet gourd) in vegetable. Whereas, Cr content varied from 0.51
mg/kg (Guava) to 2.50 mg/kg (Blackberry) in fruit, and 0.42 mg/kg (Rohu) to 1.223 mg/kg
(Catla) in fish. Cr concentrations in vegetables and fruits were lower than the recommended
limit of 11.04 mg/kg and 2.4 mg/kg dry weight set by FAO/WHO (2001) and CMH (2005)
respectively. PFA (Prevention and Food Adulteration Act) safe limit of chromium for
vegetables is 20 mg/kg (Gupta et al., 2008). The FAO/WHO guideline value of chromium in
vegetables is 0.1-0.2 µg/g (Akan et al., 2009). In this study, the vegetable Cr content was
several folds lower than that reported in Titagarh, West Bengal, India (34.83-96.30 mg/kg)
(Gupta et al., 2008). Schuhmacher et al. (1993) observed the level of Cr in Tarragona
Province, Spain, (0.01-0.21µg/g) for Northern area and (0.01-0.22 µg/g) for Southern area. Cr
concentration in radish (1.18 mg/kg) was higher than the value of 0.38 mg/kg obtained from a
suburban area of Zhengzhou city, Henan Province, China (Liu et al., 2006) but lower than the
concentration of 3.69 mg/kg had been reported in wastewater irrigated site of a dry tropical
area of India (Sing et al., 2010). From the viewpoint of public health, fruit consumption has
been shown to be beneficial for well-being that reduces the risk of many chronic diseases
(Passos et al., 2003). The chromium content in fruits was comparable with the reported values
by Hamurcu et al. (2010) in Turkey (0.18 to 0.32 mg/kg). The concentration range of Cr in
fruits from Pakistan was found between 0.10 to 22 mg/kg (jaffar et al., 2003). The Cr content
in the fish samples studied was below the maximum permissible limit of 8 mg/kg suggested
by USEPA (Islam et al., 2010). Chromium concentration in the muscle of different fresh
frozen fish of Korea was recorded between 0.10 to 1.03 mg/kg and in canned fish between
0.09 to 1.32 mg/kg (Islam et al., 2010).
3.1.4. Levels of Cadmium
Cadmium is a non-essential metal in foodstuffs and it accumulates principally in the
kidneys and liver. In all samples analyzed, its level ranged from 0.15 mg/kg (Pointed gourd)
to 1.74 mg/kg (Red amaranth) in vegetable, 0.58 mg/kg (Banana) to 3.02 mg/kg (Mango) in
fruit, and 0.22 mg/kg (Catla) to 2.11 mg/kg (Wallgo) in fish. The present concentrations of
Cd in all vegetables and fruits samples were observed to be higher than the safe limits
prescribed by EU commission regulation (European Union, 2006). Various values had been
previously reported for vegetables which included 10.37 mg/kg to 14.58 mg/kg in west
Bangal, India by Gupta et al. (2008). Our values were comparable with the values found in
Kano State, Nigeria (Akan et al., 2009). The observed values of Cd in fruits were greater than
the values of 0.06-0.16 mg/kg in some fruits grown at the roadsides of Turkey that had been
reported by Hamurcu et al. (2010). Some seasonal fruits available in Pakistan, showed
Cadmium concentration ranged from 0.05 (Guava) to 7.31(Mango) mg/kg (Jaffar et al.,
2003). According to Australian National Health and Medical Research Council (ANHMRC)
(Bebbington et al., 1977), and Western Australian Food and Drug Regulation (Plaskett and
Potter, 1979) maximum limit of cadmium in fish is 2.0 mg/kg FW and 5.5 mg/kg FW
respectively. The mean concentration of Cd in fish in this study was considerably lower than
the prescribed limits.

Narottam Saha, M. R. Zaman and M. Safiur Rahman
246
3.1.5. Levels of Arsenic
Within the selected vegetable, fruit, and fish samples arsenic (As) concentration noticed
from 0.07 mg/kg (Okra) to 0.15 mg/kg (Pointed gourd), 0.09 mg/kg (Litchi) to 0.13 mg/kg
(Blackberry), and 0.10 mg/kg (Catla) to 0.15 mg/kg (Wallgo) respectively. The recommended
and tolerance limit of arsenic in foodstuffs, water, and soil were prescribed as 1.0 mg/kg, 0.05
mg/kg and 20 mg/kg respectively (Anon, 1987). Arsenic concentration in vegetables from
Bangladesh ranged from 5 to 540 µg/kg, with a mean of 54.5 µg /kg (Rmalli et al., 2005).
According to Alam et al. (2003), the highest levels of arsenic were detected in ghotkol, taro
(loti from arum plant) and snake gourd with values of 446, 440 and 489 µg /kg, respectively.
Compared to these, the mean arsenic content in vegetables investigated in this study was
lower. Has-Schon et al. (2008) reported that the maximum allowable concentration (MAC) in
all tissues of all sorts of fishes in Croatia is 2 mg/kg or in most other countries is 1.0 mg/kg.
Maximum standard limit of As in fish is 1.4 mg/kg (wet wt. basis) for human consumption
(Nauen, 1983). According to Anon (1987) the maximum permissible limit of As in fish is 3.0
mg/kg. Saudi Arabia set a maximum contamination level of As in fish and shellfish that is 1
µg/g (SASO, 1997).
The concentrations of arsenic in fishes imported from Bangladesh and on sale in the
United Kingdom were ranged from 97 to 1318 µg /kg, with a mean value of 350 µg /kg, had
been reported by Rmalli et al. (2005). However, it is likely that the majority of this is present
as nontoxic arsenobetaine. The speciation of arsenic is not the subject of this study, but it had
been widely reported that arsenic in fish was present as nontoxic arsenobetaine.
Arsenobetaine had been reported to constitute about 70% of total arsenic in all fish tissue
samples (Ebisuda et al., 2002). In the muscle tissue of Catla from Pakistan, the As
concentration irrigated with lake water and canal water was 3.31 and 0.785 mg/kg
respectively (Arain et al., 2009) which amounts 34 times and 8 times higher than the values
observed in the present work for Catla.
3.2. ANOVA Analysis
The concentration of Pb, Mn, Cr, Cd, and As differed significantly (p < 0.05) in analyzed
ten different vegetable samples (Table 4). The concentration variation was also significant in
five different fruit samples and in five species of fish muscles (Table 4). Significant
differences in Pb, Mn, and Cd concentrations amongst three different food categories
(vegetable, fruit, and fish) were observed (Table 4). Whereas, Cr and As concentrations were
non-significant among these three categories.
3.3. Correlation between Heavy Metals in Vegetable, Fruit, and Fish
In the present study, to investigate the concentrations of heavy metals in vegetable, fruit,
and fish, correlation coefficients between metals were calculated as shown in Table 5. The
results showed that the strong positive correlation (r = 0.899) was recognized between the Cd
and Pb content of studied fruits. However, no significant correlation was found between other
metals content in vegetable, fruit, and fish samples.

Table 4 Results of ANOVA comparisons for five heavy metals concentrations in vegetable, fruit, and fish samples collected
from the central market (Shaheb Bazar) of Rajshahi city
Effect
Pb
Mn
Cr
Cd
As
df
F
p
df
F
p
Df
F
p
df
F
p
df
F
p
Vegetable samplesa
9
858.39*
0.000
9
11783.88*
0.000
9
1476.42*
0.000
9
92.52*
0.000
9
77.40*
0.000
Fruit samplesb
4
69.51*
0.000
4
1362.31*
0.000
4
6998.93*
0.000
4
178.70*
0.000
4
3.94*
0.036
Fish samplesc
4
1938.66*
0.000
4
2653.54*
0.000
4
551.83*
0.000
4
376.13*
0.000
4
37.50*
0.000
Three food categoriesd
2
38.11*
0.000
2
3.19*
0.049
2
2.68ns
0.077
2
3.24*
0.047
2
1.71ns
0.189
aVegetable samples: ten vegetable samples (see Table 1).
bFruit samples: five fruit samples (see Table 1).
cFish samples: five fish samples (see Table 1).
dThree food caterories: vegetable, fruit, and fish.
*p < 0.05; ns, non-significant

Narotam Saha, M. R. Zaman and M. Safiur Rahman
248
Table 5. Person correlation coefficients between heavy metals in vegetable,
fruit, and fish
Pb
Mn
Cr
Cd
As
Vegetable
Pb
1
Mn
-0.195
1
Cr
-0.468
0.235
1
Cd
0.240
-0.208
0.009
1
As
-0.320
0.070
0.559
-0.499
1
Fruit
Pb
1
Mn
-0.686
1
Cr
-0.551
-0.037
1
Cd
0.889*
-0.306
-0.797
1
As
-0.116
-0.063
0.339
-0.250
1
Fish
Pb
1
Mn
0.090
1
Cr
0.492
-0.703
1
Cd
-0.255
0.614
-0.535
1
As
0.125
0.858
-0.430
0.841
1
* Correlation is significant at the 0.05 level (2-tailed).
3.4. Dietary Intake of Pb, Mn, Cr, Cd, and As
The estimated dietary intake of different elements in vegetables, fruits, and fishes was
shown in Table 6, the recommended level was also included to compare and to assess whether
the heavy metals levels found in foodstuffs studied were safe for human consumption.
Contributions of vegetables, fruits, and fishes to the intake of different heavy metals were
depicted in Figure 3. The major Pb contributor was fish with 53%, followed by vegetable
(45%), and fruit (2%).
The relative contribution of vegetable, fish, and fruit to Mn intake was 70%, 19%, and
11% respectively. The relative contribution vegetable, fruit, and fish to Cr and Cd were
identical (67%, 17%, and 16% respectively).
The biggest contribution of daily intake of Mn, Cr, and Cd came from vegetable due to
the high consumption rate and Pb from fish. Although fruits contained the highest Cd and Cr
concentrations, vegetables came first in contribution to the Cd and Cr intake, as the intake of
food contaminants depends on both the contaminants concentration in the foodstuffs and on
the consumption rate of that food. Our data for Pb, Cd, and Cr were in accordance with the
daily intake estimated from the analyzed foods reported by Loutfy et al. (2012); 0.17 mg/day
for Pb, 0.03 mg/day for Cd, and 0.03 mg/day for Cr.
Our findings showed that Pb, Mn, Cr, Cd, and As intake in vegetables, fruits, and fishes
were well below the recommended dietary allowance (Table 6), suggesting no possible health
risk to consumers. The EDIs of five individual heavy metals from three food categories are
well below the oral reference dose (RfD) recommended by USEPA (2000).

Heavy Metals in Fish, Fruits and Vegetables from Rajshahi, Bangladesh
249
Table 6. Comparison of the daily dietary intakes of heavy metals from vegetable, fruit,
and fish with the recommended daily dietary allowances for a 60-kg adult
Elements
Estimated daily intake (EDI) in
mg/day/person
Recommended
daily dietary
allowance
(mg/day/person)
References
Vegetable
Fruit
Fish
Pb
0.13
0.01
0.16
0.21a
JECFA (2000);
WHO (1993)
Mn
0.12
0.02
0.03
2.0-5.0b
NRC (1989)
Cr
0.03
0.01
0.01
0.05-2b
NRC (1989)
Cd
0.03
0.01
0.01
0.06a
JECFA (1989)
As
0.00
0.00
0.00
0.13a
JECFA (1989)
The average per capita consumption of vegetable, fruit, and fish was 126, 29, and 48 g wet-
wt./day/person (Ali and Hau, 2001). Conversion factor (wet wt. to dry wt.) = 4.8
a PTDI: Provisional tolerable daily intake
b ESADDI: Estimated safe and adequate daily dietary intake
Figure 3. Contribution of vegetable, fruit, and fish to dietary intakes of Pb, Mn, Cr, and Cd in
percentage of daily intake. Estimated daily intake of As was negligible and it was not mentioned in
the pie chart.

Narottam Saha, M. R. Zaman and M. Safiur Rahman
250
CONCLUSION
In conclusion, the mean concentrations of Pb, Mn, Cr, Cd, and As in vegetables, fruits,
and fishes were found to be below the maximum permissible limits of various international
authorities except Pb that exceeded the recommended limit in vegetables and fishes, and Cd
in vegetables and fruits. Consumption of foodstuffs with elevated levels of heavy metals may
lead to high level of accumulation in the body causing related health disorders. The daily
intake of each heavy metal reported here through vegetables, fruits, and fishes was below the
respective recommended dietary allowance and the vegetables played major role in supplying
daily intake of heavy metals. Thus, adult exposure to the selected heavy metals through the
examined key food commodities in this study did not appear to be a source of unacceptable
risk at present. This study suggests that periodical monitoring and exposure assessment
studies are needed for heavy metals, at least for Pb and Cd in most of the food commodities.
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