ASSESSMENT OF LEAD IN SOIL OF RURAL
AND URBAN AREA OF GUJRAT BY USING GIS
TECHNIQUE
SYNOPSIS
BY
Ayesha Ahsan
Roll No.
18081561-001
BS ENVIRONMENTAL SCIENCES
Department of Environmental Sciences
UNIVERSITY OF GUJRAT
Session (2018-2022)
INTRODUCTION
Contamination of soils by heavy metals is of widespread occurrence as a result of
human, agricultural and industrial activities. Among heavy metals, lead is a potential
pollutant that readily accumulates in soils and sediments (Sharma, P., & Dubey, R. S,
2005). Lead is one of the major heavy metal of the antiquity and has gained considerable
importance as a potent paints, gasoline and explosives as well as disposal from
municipal sewage sludge enriched in Pb (Chaney, R. L., & Ryan, J. A, 1994). Lead is
a highly noxious and non-disintegrative heavy metal which comprises 0.002% of
Earth's crust. It is the second most toxic metal after As because of its toxic effects on
living organisms (ATSDR, 2015). Lead accumulation in soils is of serious concern in
agricultural production due to the harmful effects on soil micro-flora, crop growth and
food safety. In soil, speciation of lead greatly affects its bioavailability and thus its
toxicity on plants and microbes. The extensive use of lead has caused environmental
and human problems in many parts of world. Elemental lead is odorless, silver-bluishwhite in color, soft, highly malleable, ductile and relativity poor conductor of electricity
(Kushwaha, A., Hans, N., Kumar, S., Rani, R., A, 2018).
Studies have proven that lead have detrimental effects on soil microbial activity,
especially microbial respiration (Doelman and Haanstra, 1984). Even on short-term
exposure of metal causes significant decrease in microbial activity. Soil enzyme activity
that is chemical in nature and depends greatly upon the microbial diversity. From a
group of enzymes phosphatase are one of the important enzyme that helps in catalysing
the hydrolysis of phosphate from organic monoester linkages. Phosphate released is
very important for both plants and microorganisms (Hemida et al. 1997).
Bioavailability and mobility of Pb in polluted soils is governed by several soil physiochemical properties such as pH, ion exchange capacity, metal speciation, redox
potential, soil microbial community, concentration of ligands, competing cations and
soil mineralogy (Zulfiqar et al. 2019). Significant exposure to lead is an environmental
threat to optimal health and to physical development in young children that affects all
socio-economic groups. Lead absorbed into the body, whether by oral ingestion or by
inhalation enters the blood stream where it rapidly becomes attached to red blood cells
or is transported to soft tissues. Subsequently, it is transferred to bone where the
reservoir is large with long half-life. Lead in blood is primarily bound to RBC (99%)
rather than plasma and lead to lead toxicity which can cause immunity issues, nervous
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system disorders and many other relating issues (Flora, S. J., Flora, G., & Saxena, G.
2006).
Lead occurs in all ecological spheres (Pourrut et al., 2011) and pollutes the environment
by means of pedogenic as well as anthropogenic practices. Its mobilization, erosion and
volcanic eruption are natural sources which contribute only minute fraction of
environmental contamination (Yokel and Delistraty, 2003). The contribution of natural
sources of lead to concentrations in the environment is low compared to the contribution
from human activities (Breen, J.J. and Stroup, C.R. (eds.), 1995). Some of the minerals
of granite rocks, principally those containing radioactive elements (for example,
monazite, xenotime, uraninite, thorite, zircon, allanite, titanite) contain greater
concentrations of lead. Sedimentary rocks contain comparatively small amount of lead,
average lead concentration, 32 mg/kg for carbonaceous shale, 23 mg/kg for siltstone,
mudstone, claystone, and noncarbonaceous shale, 17 mg/kg for sandstone, and 11
mg/kg for limestone and dolomite (Lovering, T. G. 1969). Through human activities
such as mining, smelting, refining, manufacturing, and recycling, lead finds its way into
the air, water, and surface soil. Lead-containing manufactured products (gasoline, paint,
printing inks, lead water pipes, lead-glazed pottery, lead-soldered cans, battery casings,
etc.) (McElvaine et al. 1992). Lead is the major pollutant in both Terrestrial and aquatic
ecosystem. Besides natural weathering processes the main sources of lead pollution are
exhaust fumes of automobiles, chimneys of factories using lead, effluents from the
Storage battery, industry, mining and smelting of lead ores, metal plating and finishing
operations, fertilizers, pesticides and additives in pigments and gasoline (Eick, M.J et
al., 1999).
Heavy metals are highly hazardous to the environment and organisms. It can be
enriched through the food chain. Lead in contaminated soil and dust can find its way
into the food and water supply. Once the soil suffers from heavy metal contamination,
it is difficult to be remediated. Agriculture and food waste, farmyard manure, logging
and timber industry wastes, municipal wastes, municipal sludge, organic wastes, metal
processing solid wastes, coal ash, fertilizer, marl, commodity impurities, atmospheric
deposition are the Different sources of Pb contaminating soils annually in the world. In
the past, soil contamination was not considered as important as air and water pollution,
because soil contamination was often with wide range and was more difficult to be
controlled and governed than air and water pollution. However, in recent years the soil
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contamination in developed countries becomes to be serious. It is thus paid more and
more attention and became a hot topic of environmental protection worldwide (Su, C.
2014). Heavy metals in the atmosphere are mainly from gas and dust produced by
energy, transport, metallurgy and production of construction materials. Excepting
mercury, heavy metals basically go into the atmosphere in the form of aerosol and
deposit to the soil through natural sedimentation and precipitation, etc. For example,
the lead pollution (Lin, Z., Harsbo, K., Ahlgren, M., & Qvarfort, U. 1998) stated that
in a downtown, Central Sweden, was reported mainly from the urban industrial copper
plant, sulfuric acid plant, paint factory, and the large amount of waste from mining and
chemical industries. Due to transporting by wind, these fine lead particles spread from
industrial waste heap to surrounding areas.
City/Country
Beijing
Guangzhou
Shanghai
Changsha
Hong Kong
Qingdao
Baoji
Luoyang
Wenzhou
Nanjing
Cincinnati
Pb (mg/kg-1)
28.60
108.55
70.69
89.40
94.60
62.00
25380.55
65.92
65.22
107.30
41.00
Syria
France
Spain
Iran
Turku, Finland
17.00
43.14
1505.45
46.59
17.00
Table 1. The content of Pb in urban soils worldwide mg/kg-1 (Su, C. 2014).
In Pakistan, a study by Aga Khan University in Karachi showed that 80% of children
aged 36 to 60 months had blood lead concentrations 10 µg/dl and that living near the
city centre, application of surma and child's habit of hand-to-mouth activity were
associated with elevated lead concentrations in blood. A survey for lead poisoning in
lead factory workers in Pakistan showed median blood lead levels of 61.20
micrograms/dl. In this issue of JPMA, Agha et al present their study on blood lead
levels in traffic policemen in Islamabad which shows that these policemen have
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markedly elevated blood lead levels. In another study on policemen from Karachi,
which has a greater concentration of public and private transport vehicles, the mean
blood lead levels were higher than the study in Islamabad. The major environmental
sources of lead exposure include, air, dust, soil, drinking water and food contaminated
with lead. Occupations that impose greater risk for lead poisoning include welding, iron
foundry workers, glaze workers, ship breaking, plumbing, traffic police, repair of
automobile radiators, paint industry, lead smelting and refining, pottery and ceramic
ware production and many others (Kazmi, T., & Omair, A. 2005). The source of lead
in the ready to use henna is from the artificial chemical additives in henna paste, added
to enhance the color and also to speed up the dying of the henna tattoo in hand, feet,
and body (Rehan, I. et al., 2019). Traffic density is continuously increasing in the
Punjab, the most populated province of Pakistan. Traffic load is very high mainly
comprised of trucks, buses, vans and animal driven carts, industrial emissions and lead
containing waste etc. is the cause of releases large quantities of metals (Khalid, N. et
al., 2018), that deposits on soil and deteriorate soil quality. According he Punjab
Environmental Quality standards the permissible level of lead for industrial emission is
50 mg/Nm3, for effluents by municipal and industries it is 0.5 mg/l, for air it is annually
1 µg/m3 and by mean of 24 hours it is 1.5 µg/m3 (Punjab Environmental Quality
Standards by EPD, 2016)
In Gujrat city, Pakistan Pb concentration was found higher at all locations and Kachari
Chowk holds the maximum concentration of Pb in soil samples while other locations
were not significantly different from each other. Contamination level of Pb was at
elevated levels in metropolitan areas when large number of vehicles passed at the timing
of rush hours. The heavy metals emitted from automobiles exhaust dispersed in the
atmosphere and then accumulated in the surrounding environment, soil plant, fruits
(which kept by vendors in open air). Further these heavy metals taken up by human
beings and biomagnified in food chain and food web. Approximately 3600 automobiles
passing through this point which includes, rickshaws, motor bikes, cars, buses/mini
buses, hiace/bolan etc. Lead also entered into the atmosphere by wind erosion, during
sludge transportation and sludge extraction (Bashir N., et al., 2017). A study was
conducted by yang. (2011) that Pb contamination was due to over urbanization and
industrialization but in current study this might be due to congested traffic pollution.
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Heavy metals in urban soils may go into the human body through skin absorption and
inhalation of dust, etc., and thus directly damage, especially children's health. They also
affect the urban environmental quality and damage human health indirectly through
polluting the food, water and atmosphere. Pb mainly enters human body through the
digestive tract and respiratory tract, and then goes into the blood circulation in the form
of soluble salts, protein complexes or ions, etc. 95% of the insoluble phosphate lead
accumulates in bones. Pb is strongly pro-organizational. It affects and damages many
of the body organs and systems, such as kidney, liver, reproductive system, nervous
system, urinary system, immune system and the basic physiological processes of cells
and gene expression (Su, C. 2014). A study was conducted by Yabe et al. (2010) found
that the contaminated soil dust in the city was an important factor to affect human
health. According to the survey, there is about 30% of Chinese children's blood whose
content of Pb exceeds the home standard (100 g/ L); this rate in cities is more than 60%.
The heavy metal contaminate in agricultural soil becomes the part of crops and
ultimately become the part of food chain and damage human health (Aeliona et al.,
2008).
Lead when exposed to human it causes several effect such as Hematopoietic System,
Renal Effects, Neurological and neurobehavioral Effects, Immunological Effects,
Reproductive Toxicity, Effects on Bone, Carcinogenic effects, cardiovascular
disorders, Oxidative stress. Acute poisoning is uncommon. It results from inhalation of
large quantities of lead, or through ingestion of large oral dose. The clinical symptoms
of acute poisoning are characterized by metallic taste, abdominal pain, vomiting,
diarrhea, anemia, oliguria, collapse and coma. Chronic effects are more common and
can be described in three stages of progression The early stage is characterized by loss
of appetite, weight loss, constipation, irritability, occasional vomiting, fatigue,
weakness, gingival lining on gums and anemia, The second stage is marked by
intermittent vomiting, irritability, nervousness, tremors and sensory disturbances in the
extremities, most often accompanied by stippling of red blood cells and a severe stage
of toxicity is characterized by persistent vomiting, encephalopathy, lethargy, delirium,
convulsions and coma (Flora, S. J., Flora, G., & Saxena, G. 2006).
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Objectives of the Study
Problem Statement
Significance of the Study
Hypotheses
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