Methods
for Analysis of Metals
•
Spectroscopy
(Colorimetry, absorption spectrophotometry)
•
Emission
spectrometry (AES)
•
Inductively
coupled plasma- atomic emission spectroscopy (ICP-AES) and ICP-MS
•
Atomic
absorption spectroscopy (AAS)
•
X-ray
fluorescence (XRF)
•
Neutron
activation analysis (NAA)
•
Electrochemical
methods
•
Spark
source mass spectrometry (SSMS)
•
Chromatography
•
Conventional
methods
Monitoring
Techniques
Clearly the selection of
monitoring techniques for the determination of radioactive contaminants in
foodstuffs is mainly dependent on
–
the
concentration,
–
type
and number and location of the samples,
–
the
availability,
–
cost
and limit of detection of the facility and
–
the type of information required
Among these, lower limit of
detection is of prime importance
Clearly the selection of
monitoring techniques for the determination of radioactive contaminants in
foodstuffs is mainly dependent on
–
the
concentration,
–
type
and number and location of the samples,
–
the
availability,
–
cost
and limit of detection of the facility and
–
the type of information required
Among these, lower limit of
detection is of prime importance
Routs of
Entry
•
Ingestion
•
Inhalation
•
Injury/skin
Environmental
Levels of Heavy Metals
Type
|
Cu
|
Cd
|
Pb
|
Fresh
Food
|
~1mg/kg
|
0.005-0.1mg/kg
|
0.01-2.5
mg/kg
|
Drinking
Water
|
1 mg–1mg/L
|
< 5
mg/L
|
<
30 mg/L
|
Dry
Soil
|
2–100mg/kg
|
< 1
mg/kg
|
2 –
200 mg/kg
|
Ambient
Air
|
10–70ng/m3
|
1–3
ng/m3
|
0.02 –
10 mg/m3
|
Diseases
Caused by Heavy Metals
Lead
(Pb): Recognized as a heavy poison. Absorbed 10% (ingestion) and 15-30%
(inhalation). About 95% is deposited in bones and small quantities accumulate
in the brain causing following possible effects:
•
Damage IQ & learning ability
|
•
Criminal tendencies
|
•
CNS defects
|
•
Acute encephalopathy
|
•
Demyelination
|
•
Peripheral nerve dysfunction
|
•
Genetic disturbances
|
•
Restlessness
|
•
Suicidal tendencies
|
Acute poisoning causes GI colic & encephalopathy (frequent in
children). Anemia is chronic systematic effect.
Prolonged absorption – chronic encephalopathy.
Cadmium
(Cd): Absorbed 10-15% by inhalation and 50% by ingestion. Extremely toxic and
accumulates in human mainly in the kidneys and liver. Long term exposure causes
lung cancer and gastrointestinal disease, even intake of very small amounts
leads to dysfunction of kidneys. Acute inhalation – pneumonitis. Accidental –
fatalies.
Mercury
(Hg): Metal and its compounds y toxic. Used in medicines. Chronic poisoning
leads to reddening and bleeding of gums, digestive disturbances, deafness and
tumors of hands.
Thallium
(Tl): Very toxic, interfering Na-K metabolism. Used in medicines. Large doses
cause GI hemorrhage, gastroenteritis, a rapid heartbeat and headache. Chronic
cases lads to spinal card damage.
Arsenic
(As): Not essential, used for treatment of skin and anemia. Acute doses – death
in 1-2 hours. Chronic poisoning- damage GIT, CNS and skin. Carcinogenic–skin
& internal organs.
Nickel
(Ni): In traces, not highly toxic. Diet
contains 0.3-0.5 mg/d. Mainly effects enzyme systems. Poison mainly for brain
& lungs. Occupational exposure – cancers of nose, larynx, lung &
kidney.
Bismuth
(Bi), Gallium (Ga) and Indium (In) are moderately toxic.
Iron
(Fe): Essential micronutrients, required for proper functioning of hemoglobin
in blood circulation and transport/storage of oxygen. Vegetables best source.
Zinc
(Zn): Essential for growth. Mainly in liver, kidneys, muscles and pancreas.
Deficiency – Acrodermatis Entospathica/cardiovascular diseases. Acute –
gastroenteritis. Accidental poisoning – testicular diseases.
Chromium: Essential
for metabolism of glucose and lipids. Average intake is 30-100 mg/d. Deficiency increases the toxicity of Pb.
Chronic – skin diseases. Occupational exposure –bronchogenic carcinomas
(carcinogenic).
Copper
(Cu): Essential to human. Acts as a catalyst for fats. The adult daily
requirement has been estimated to 2 mg; however, excess is harmful causing
gastrointestinal disturbances, hemolysis, kidney and liver damages. Inhalation
causes irritation in respiratory tract.
Manganese
(Mn): Essential trace element, serve as liver & other enzymes. Poisoning –
mental disorders accompanying a syndrome resembling paralysis agitans, and
inflammation of the respiratory system.
Cobalt
(Co): Essential trace metal, with
vitamin B12 (coenzyme) – formation of erythrocytes.
Analysis
of beef meat for selected heavy metals
Sites
|
Time
|
Age
(yrs)
|
ppm
|
||
Pb
|
Cd
|
Cu
|
|||
1.
Pabbi
|
6 am
|
2
|
5.4
|
1.8
|
1.3
|
2.Hayatabad
|
7 pm
|
3
|
8.0
|
0.9
|
10.0
|
3.Board
|
8 pm
|
3-4
|
10.0
|
6.6
|
7.0
|
4.Palosi
|
10 pm
|
3½
|
6.6
|
7.0
|
10.0
|
5.Tehkal
Payan
|
11 am
|
2-3
|
10.0
|
6.3
|
2.0
|
6.Nothea
|
12
noon
|
3-4
|
10.5
|
3.0
|
12.0
|
7.Khyber
Bazar
|
3 pm
|
2-3
|
7.0
|
10.0
|
10.0
|
8.
Bacha Kkhan Chowk
|
4 pm
|
3
|
16.6
|
15.0
|
3.5
|
9.Hashtnagri
|
5 pm
|
3-4
|
10.0
|
10.0
|
13.0
|
2.5
|
0.1
|
1.0
|
|||
Analysis
of samples from raw sugar cottage industries
Site/City
|
No.
|
Cd
|
Pb
|
Cu
|
Fe
|
Mardan
Gur
|
1
2
3
|
0.40
0.09
0.05
|
0.08
-
0.04
|
0.29
2.60
0.35
|
7.2
7.6
6.4
|
Mean
Std
Dev.
C.V.
|
0.18
0.19
105.6
|
0.04
0.04
100.0
|
1.08
1.32
121.9
|
7.1
0.6
8.6
|
|
Peshawar
Gur
Market
|
1
2
3
4
|
0.08
-
0.03
0.04
|
-
0.17
0.22
2.00
|
0.93
0.35
4.0
-
|
10.9
6.4
7.2
10.0
|
Mean
Std.
Dev.
C.V.
|
0.04
0.03
86.8
|
0.60
0.94
157.2
|
1.32
1.83
138.4
|
8.6
2.1
25.0
|
|
Charsadda
Gur
|
1
|
0.03
|
0.03
|
4.0
|
6.05
|
Sugar
(Pesh)
|
1
|
0.04
|
1.60
|
-
|
10.0
|
Vegetables
grown on sewerage water
Sample
|
Fe
|
Cu
|
Ni
|
Pb
|
Mn
|
Co
|
Zn
|
Cd
|
Cr
|
Okra
|
|||||||||
Root
|
529.5
|
2.15
|
1.25
|
-
|
40.25
|
2.75
|
26.25
|
-
|
-
|
Stem
|
115.25
|
5.75
|
4.00
|
-
|
46.50
|
3.50
|
38.50
|
-
|
-
|
Leave
|
651.5
|
5.5
|
1.75
|
-
|
76.25
|
3.25
|
48.75
|
0.5
|
2.55
|
Fruit
|
157.75
|
6.0
|
2.0
|
-
|
56.0
|
2.25
|
63.0
|
-
|
-
|
Maize
|
|||||||||
Root
|
1751.5
|
9
|
4.5
|
0.5
|
62
|
5.5
|
71.5
|
4.5
|
21.0
|
Stem
|
105.5
|
2.5
|
0.5
|
-
|
32.5
|
3.5
|
34.0
|
-
|
-
|
Leave
|
411.5
|
4
|
1.0
|
-
|
49
|
1.5
|
39
|
-
|
-
|
Luffa
|
|||||||||
Root
|
1097.5
|
9.5
|
2.5
|
1
|
62
|
0.5
|
43.5
|
-
|
7
|
Leave
|
1361.5
|
9.0
|
3.5
|
-
|
81.5
|
2
|
67
|
-
|
10.5
|
Stem
|
109.5
|
3.5
|
3.0
|
-
|
41.0
|
1.5
|
17.5
|
-
|
6.0
|
Tomato
|
|||||||||
Root
|
1823.0
|
95.0
|
4.5
|
1.5
|
48.0
|
4.0
|
76.0
|
-
|
20.5
|
Stem
|
389.5
|
2.5
|
1.0
|
-
|
32.5
|
1.5
|
41.0
|
1.0
|
1.5
|
Leave
|
1644.5
|
4.5
|
3.5
|
-
|
47.0
|
2.5
|
27.0
|
-
|
3.5
|
Vegetables
grown on canal and tape water
Sample
|
Fe
|
Cu
|
Ni
|
Pb
|
Mn
|
Co
|
Zn
|
Cd
|
Cr
|
|
CANAL WATER
|
||||||||||
Okra
|
||||||||||
Root
|
1106.5
|
7.5
|
3.0
|
-
|
49.0
|
0.50
|
36.0
|
-
|
6.5
|
|
Stem
|
85.5
|
30.0
|
1.0
|
-
|
34.0
|
2.50
|
3.50
|
-
|
-
|
|
Leave
|
567.0
|
5.50
|
0.50
|
-
|
144.0
|
3.0
|
64.0
|
-
|
-
|
|
Fruit
|
182.5
|
8.5
|
0.50
|
-
|
46.5
|
3.5
|
58.0
|
-
|
-
|
|
Maize
|
||||||||||
Root
|
1751.5
|
9.0
|
4.5
|
0.5
|
62.0
|
5.5
|
71.5
|
4.5
|
21.5
|
|
Stem
|
105.5
|
2.5
|
0.5
|
-
|
32.5
|
3.5
|
34.5
|
-
|
-
|
|
Leave
|
411.5
|
4.0
|
1.0
|
-
|
49.0
|
1.5
|
39.0
|
-
|
-
|
|
Tomato
|
||||||||||
Root
|
963.5
|
11.0
|
1.0
|
-
|
58.0
|
1.0
|
80.0
|
-
|
3.5
|
|
Stem
|
165.5
|
2.5
|
2.5
|
-
|
34.0
|
2.0
|
18.0
|
1.0
|
-
|
|
Leave
|
1166.0
|
5.0
|
3.5
|
0.5
|
89.0
|
1.5
|
21.5
|
-
|
4.0
|
|
TAPE WATER
|
||||||||||
Brassica
|
||||||||||
Root
|
446.5
|
11.0
|
1.5
|
0.5
|
2.57
|
3.5
|
39.5
|
-
|
3.5
|
|
Stem
|
68.5
|
10.0
|
2.0
|
-
|
21.5
|
3.0
|
10.5
|
-
|
-
|
|
Leave
|
664.5
|
14.5
|
1.0
|
1.5
|
41.5
|
3.0
|
34.5
|
1.0
|
3.0
|
|
Fruit
|
162.0
|
16.5
|
1.0
|
-
|
30.5
|
2.5
|
48.5
|
-
|
-
|
|
Concentration
of selected elements whole plant grown on sewerage, canal and tape waters
Sample
|
Fe
|
Cu
|
Ni
|
Pb
|
Mn
|
Co
|
Zn
|
Cd
|
Cr
|
SEWERAGE WATER
|
|||||||||
Okra
|
1296.0
|
13.5
|
7.0
|
-
|
163.0
|
9.5
|
113.5
|
0.5
|
2.2
|
Maize
|
2268.5
|
15.5
|
6.0
|
0.5
|
143.5
|
10.5
|
144.5
|
4.5
|
21.0
|
Luffa
|
2568.5
|
22.0
|
9.0
|
1.0
|
184.5
|
4.0
|
128.0
|
-
|
23.5
|
Tomato
|
3857.0
|
18.0
|
9.0
|
1.5
|
127.5
|
8.0
|
144.0
|
1.0
|
25.5
|
CANAL WATER
|
|||||||||
Okra
|
1759.0
|
16.0
|
4.5
|
-
|
227.5
|
6.0
|
135.0
|
-
|
6.5
|
Maize
|
2149.0
|
14.0
|
5.5
|
-
|
165.0
|
4.5
|
122.0
|
-
|
19.5
|
Tomato
|
2295.0
|
185.0
|
7.0
|
0.5
|
181.0
|
4.5
|
119.5
|
1.0
|
7.5
|
TUBE-WELL WATER
|
|||||||||
Brassica
|
1179.5
|
35.5
|
4.5
|
2.0
|
90.0
|
9.5
|
84.5
|
1.0
|
3.0
|
Results
• Consumption of contaminated food
crops, meat and milk significantly increased the levels of trace metals in
human blood as compared to the control area.
• Indicates - food chains is one of
the major pathways of exposure of contamination of human blood with metals.
• Overall metal concentrations in
males were higher as compared to females which may be due to diet habits and
body mass along with other factors.
Old age
people had accumulated higher concentrations of trace metals as compared to
younger ones due to slow accumulation of the metals in their bodies
•
Pakistan
is losing Rs 622 million annually due to absence of laws on quality standards
in different sectors. Consumer Rights Commission of Pakistan (CRCP) has
expressed serious concerns over non-implementation of the National Quality
Policy of Pakistan.
•
The
Pakistan Standards and Quality Control Authority (PSQCA), registered 48,000
standards, most of which have been adopted from ISO.
•
But
Authority lacks the capacity to enforce them.
•
CRCP
demanded that the government should strengthen PSQCA and PNAC.
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