Heavy metals toxicity assessment

1. Ecological
Risk
Assessme
nt of
Heavy
Metals
PRESENTED BY
AFIFA (2)
FAKIHA (12)
H.ARSALNA (30)
BISMAH (35)
QURAT UL AIN (17)
AFIFA GOHAR (48)
TAYYAB (41E )

2. Jens
Martensson
2
Heavy metals
Heavy metals are a group of metals and metalloids that have relatively high
density and are toxic even at ppb levels
Essential elements are often required in trace amounts in the level of 10–15 ppm
and are known as micronutrients.
EPA and the International Agency for Research on Cancer (IARC) have classified
heavy metals as human carcinogen.
Because of their high degree of toxicity, arsenic, cadmium, chromium, lead, and
mercury rank among the priority metals that are of public health significance.
Heavy metals are also considered as trace elements because of their presence in
trace concentrations (ppb range to less than 10ppm) in various environmental
matrices

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Martensson
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The HMs can be broadly
classified into two categories:
essential and nonessential
heavy metals
Essential HMs are those required by living organisms for carrying out the
fundamental processes like growth, metabolism, and development of
different organs. There are numerous essential heavy metals like Cu, Fe,
Mn, Co, Zn, and Ni required by plants as they form cofactors that are
structurally and functionally vital for enzymes and other proteins.
Nonessential heavy metals like Cd, Pb, Hg, Cr, and Al are not required by
plants, even in trace amounts, for any of the metabolic processes. Table
6.1 depicts the manifestation of toxicity induced by copper, zinc,
cadmium, and lead to different plant species.
There is a very narrow range of concentrations between beneficial and
toxic effects

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Martensson
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Properties
Unlike organic pollutants, heavy metals are nonbiodegradable and have
tendency to accumulate in living beings.
Heavy metals induce detrimental effects, including developmental toxicity, cell
death, neurotoxicity, oxidative stress, and immunotoxicity.
Owing to their bioaccumulative potential along the food chain, high toxicity,
prevalence, and persistence in the environment, heavy metals have become a
major public health concern.
Heavy metals commonly accumulate in living organisms because of the non-
biodegradable, toxic nature of heavy metals, and non-thermo degradable.

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Martensson
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Sources
Although heavy metals are naturally occurring elements that are found
throughout the earth’s crust, most environmental contamination and human
exposure result from anthropogenic activities such as mining and smelting
operations, industrial production and use, and domestic and agricultural use of
metals and metal-containing compounds metals are released into the
environment by both natural and anthropogenic sources such as industrial
discharge, automobiles exhaust, and mining.
Their multiple Industrial, domestic, agricultural, medical and technological
applications have led to their wide distribution in the environment; raising
concerns over their potential effects on human health and the environment.
Industrial sources include metal processing in refineries, coal burning in power
plants, petroleum combustion, nuclear power stations and high tension lines,
plastics, textiles, microelectronics, wood preservation and paper processing
plants.

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Martensson
Routes Of Exposure

7. Jens
Martensson
• effects of exposure to heavy metals can vary
depending on the type of metal, the route of
exposure, and the duration and level of exposure.
• Some heavy metals, such as lead and mercury, can
have serious health effects even at low levels of
exposure.
• Other heavy metals, such as copper and zinc, are
essential to human health in small amounts but can
be toxic at higher levels.
Routes Of Exposure
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Martensson
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Toxicokinetics
Toxicokinetics describes how the body handles a chemical, as a function of
dose and time, in terms of the concept of ADME (absorption, distribution,
metabolism and excretion): The rate of chemical absorption from the site of
application into the blood stream.

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Martensson
ABSORPTION
• Inhalation: Heavy metals can be inhaled as fumes, dust, or
mist. This is a common route of exposure for workers in
industries that involve metal processing, smelting, and welding.
• Ingestion: Heavy metals can enter the body through the
gastrointestinal tract, either by consuming contaminated food
or water or by accidental ingestion.
• Dermal Contact: Heavy metals can also enter the body
through the skin, for example, through contact with
contaminated soil or through the use of cosmetics or other
personal care products that contain heavy metals.
Toxicokinetic Of Heavy Metal
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Martensson
• DISTRIBUTION
• Some heavy metals, such as lead and cadmium, have a high
affinity for bone and can accumulate in bone tissue over time.
Other heavy metals, such as mercury, tend to accumulate in the
kidneys and brain.
• Some heavy metals, such as iron, are essential for the body's
normal function and are tightly regulated. Others, such as lead,
cadmium, and mercury, have no known essential function in the
body and can accumulate in the body over time with repeated
exposure.
Toxicokinetic Of Heavy Metal
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Martensson
• METABOLISM
heavy metals, such as lead, cadmium, and mercury,
have no known essential function in the body and can
accumulate in the body over time with repeated
exposure. These metals can disrupt normal cellular
processes and can bind to various proteins, enzymes,
and nucleic acids, altering their function.
Toxicokinetic Of Heavy Metal
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Martensson
• Lead: Lead can bind to several enzymes and proteins
in the body, causing them to malfunction.
• Cadmium: Cadmium can bind to metallothionein, a
protein that regulates the uptake and elimination of
heavy metals, which can lead to the accumulation of
cadmium in the body.
• Mercury: Mercury can bind to and inactivate enzymes
in the body, and can also form a complex with a
specific protein called metallothionein, which can lead
to the accumulation of the metal in the body.
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Martensson
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Toxic
Mechanisms
of Five Heavy
Metals:
Mercury,
Lead,
Chromium,
Cadmium,
and Arsenic

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Martensson
• Excretion
• Excretion of heavy metals refers to the process by which the
body eliminates these metals from the body. The excretion of
heavy metals varies depending on the specific metal and can
occur through urine, feces, sweat, or hair.
• Urine: Heavy metals such as lead, cadmium, and mercury can
be excreted through urine. However, the efficiency of excretion
through urine can vary depending on the individual's health
status, genetics and nutritional status.
Toxicokinetic Of Heavy Metal
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Martensson
• Feces: Some heavy metals such as lead and cadmium
can be excreted through feces.
• Sweat: Heavy metals such as cadmium and lead can be
excreted through sweat. However, the efficiency of
excretion through sweat is generally low compared to
urine and feces.
• Hair: Heavy metals can also be excreted through hair,
but it's not a common route of elimination, and hair
analysis is not a reliable indicator of exposure.
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Martensson
MERCURY
LEAD
CADMIUM
ARSENIC
Health effects of
Heavy Metals
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17. Jens
Martensson
Among lead's well-
known developmental
health effects
is stunting of skeletal
growth in children.
Moreover, lead is known
to delay fracture
healing and may
contribute to
osteoporosis.
Lead
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Permissible Standards for lead
are
• The lead standards
establish a permissible
exposure limit (PEL) of 50
μg/m3 of lead over an
eight-hour time-weighted-
average for all employees
covered.
• The calculated IRLs are 2.2
micrograms (µg) per day
for children and 8.8 µg
per day for females of
childbearing age.

18. Jens
Martensson
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19. Jens
Martensson
Mercury majorly cause Minamata
disease
It may
• Deteriorates nervous system
• Impairs hearing, speech, vision, and gait
• Cause involuntary muscles movements
• Corrodes skin and mucous membranes
• Cause chewing and swallowing to become difficult
Mercur
y
OSHA: The legal
airborne permissibl
e exposure
limit (PEL) is 0.1
mg/m3 averaged
over an 8-hour
work shift
Symptoms
include
• Tremors
• Insomnia
• memory loss
• neuromuscular
effects
• Headaches
• cognitive and
motor

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Martensson
Cadmiu
m
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Cadmium have many adverse effects
on different parts or organs of body
Respiratory system
• Pneumonia
• Destruction of mucous membrane
Kidney
• kidney stones
• Glomerular and tubular damage
Reproductive system
• Testicular necrosis
• Estrogen like effects
• Infection of steroid hormones
Skeletal system
• Loss of bones density
• Itai itai disease

21. Jens
Martensson
Permissible level of arsenic
• The permissible exposure limit for arsenic is no greater than 10 micrograms of
inorganic arsenic per cubic meter of air, averaged over any 8 hour period for a 40
hour workweek [OSHA 2001; NIOSH 2005].
• The current drinking water standard, or Maximum Contaminant Level (MCL), from the
U.S. Environmental Protection Agency (EPA) is 0.010 mg/L or parts per million
(ppm).
Arsenic
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Martensson
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23. Heavy metals

24. Jens
Martensson
The concentrations of heavy metals (Cr, Cd, Hg, Cu, Zn, Pb and As) in
sediment, and fish were investigated in the middle and lower reaches of
the Yangtze River, China. The samples were collected from the main
river and lakes in the Yangtze River basin at 17 sites in the middle reach
and from 10 sites in the lower reach. In total, 27 water and sediment
samples were collected.
HM concentration in sediments:
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Martensson
The lakes had the highest mean concentrations of Hg, Pb, Cr, Cu, Zn,
and OM, while the lower reach of the main river had the highest mean
concentrations of Cd, As, TN, and TP. Mean concentrations of metals in
the middle reach were relatively lower. This may be due to the
downstream movement of water. The heavy metal concentrations in the
sediments were higher in the lakes than in the river. We suggest that this
was due to the higher flow disturbance in the river that led to re-
suspension and downstream movement of pollutants.
HM in sediments
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26. Jens
Martensson
• The potential ecological risk index (RI) was introduced to assess the
degree of heavy metal pollution in sediments, according to the
toxicity of heavy metals and the response of the environment
• Hg posed a considerable ecological risk at five sites and a
moderate risk at two. Additionally, Cd and As also posed relatively
high ecological risks in these areas. The high ecological risks of
these three heavy metals in freshwater ecosystems are
consequences of their high toxic-response factors.
Ecological risk assessment
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27. Jens
Martensson
• In terms of their spatial distribution, sites with moderate or
considerable potential ecological risk indices for Hg and Cd
were located near to large cities (Wuhan, Nanjing, and
Jiangyin), or ports (Chenglingji), or lakes with high human
activity (Dongting Lake and Donghu Lake).
• The highest potential ecological risk indices for As were found
in the lower reach, mainly downstream of Poyang Lake.
• For other metals (Pb, Cu, Cr, and Zn), the potential ecological
risk indexes were low. The potential ecological risk indices for
single regulators indicated that the severity of pollution of the
seven heavy metals decreased in the following sequence: Hg >
Cd > As > Cu > Pb > Cr > Zn
Ecological risk assessment
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28. Jens
Martensson
• Two sites among twelve in the middle reach of the main river
exhibited moderate or considerable ecological risk. Most of the
lakes and sites in the lower reach of the main river posed
moderate or considerable ecological risk. The RI values were
clearly related to the degree of anthropogenic disturbance.
• For example, the Tian’ezhou wetland, which is a natural
conservation area in China, had the lowest heavy metal
concentrations and minimal potential ecological risk, while
sites near to big cities (such as Wuhan, Nanjing, and Jiangyin)
had relatively high ecological risks.
Ecological risk assessment
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29. Jens
Martensson
According to the potential ecological risk index, Hg represented
a moderate risk at 7.4% of sites, and a considerable risk at 18.5%
of sites; Cd posed a moderate risk in 37% and As in 22% of the
regions. The ecological risk for all factors (RI) showed that 7.4%
of sample sites belonged in the category of considerable risk,
and 33% were of moderate risk.
In accordance with the high potential ecological risk of the
metals Hg, Cd, and As in sediments, the four metals Pb, Cd, Hg
and As, were the most important with respect to health risks
Conclusion
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30. Jens
Martensson
Heavy metals in Landfill Leachate

31. Jens
Martensson
Introduction:
• Heavy metals contained in waste have for years been disposed of in dumps and
landfills.
• Organic matter in landfill leachate binds heavy metals strongly and colloidal matter has
a high affinity for heavy metals. The presence of organic complexes and colloidal-
bound heavy metals in leachate-polluted groundwater affects the total concentration
as well as the behavior of heavy metals in the aquifer.
• The purpose of this paper is to determine the distribution of heavy metals between
different species in leachate-polluted groundwater sampled down gradient of an
actual landfill.
• Organic bound species were determined by a speciation procedure involving an
anion-exchange column and the distribution of heavy metal species in the inorganic
part of the truly dissolved fraction was calculated using a geochemical speciation
model.

32. Jens
Martensson
Sampling Site:
• Two landfill-leachate polluted groundwater samples were collected down gradient at
two different depths of 7 m with area strongly anaerobic with a high content of organic
matter.
Sampling procedure:
• One leachate-polluted groundwater sample 2 m below the groundwater table with a
Teflon tube.
• Other with stainless steel tube 5 m below with low oxygen diffusion coefficient.
• Turbidity, pH, specific conductivity and temperature were monitored during the
pumping to ensure equilibrium before the samples were collected and no samples
were collected until all these indicator parameters had reached steady values.

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Martensson
Methodology:
Size Fractionation:
• The spiked leachate-polluted groundwater samples were separated into size fractions
using the pore sizes 0.40,0.010 and 0.001 mm.
Chemical Analysis:
• Specific conductivity, pH and alkalinity were measured immediately after the filtration
in all size-fractions.
Calculation of heavy metal species:
• A geochemical model was used in order to estimate dissolved inorganic species in the
samples.
Anion Exchange Technique:
• Reference solutions were used to caught only organic species and determined by TOC
content.

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Martensson
Heavy Metal Distribution:
• Four categories (inorganic colloidal metal species, , organic colloidal metal species,
organic dissolved metal species, inorganic dissolved metal species.
• For Cd, Cu and Pb the fractions of organic species dominated (>59%). The inorganic
colloidal species were 1-41% ,dissolved inorganic species only constituted a very small
part.
• Ni and Zn the dissolved inorganic species were 30% L1 of the metal content and for
about 70% in L2. In both groundwater samples 2-40% of the total content of Ni and Zn
was free metal ions, whereas the organic fractions contained 15-62% of the total
content of Ni and Zn.

35. Jens
Martensson
Conclusion:
• Colloidal matter was found in spiked leachate-polluted groundwater
samples, but the truly dissolved fraction (<0.001 mm) constituted 79-84% of
the total solids probably as inorganic salts and small organic molecules.
• Most of the colloids were small and consisted to a large extent of organic
matter. Fe, Ca, S and Cu were found in the colloidal fractions. This indicated
that both clay type particles, organic matter and precipitates were present
in sample.
• Speciation by an anion-exchange technique showed that the heavy metals
complexed strongly with the organic matter in leachate-polluted
groundwater, especially with respect to Cd, Cu and Pb. More than 60% of
Cd, Cu and Pb were found to be organic species.
• Results suggests except for Zn, heavy metals are strongly associated with
small-size colloidal matter, which is to a large extent organic matter. This
implies that the behavior of heavy metals in the environment may differ
from the behavior expected for truly dissolved heavy metal

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37. Jens
Martensson
Assessment of heavy metals to determine ecological risk
through measurement of biotic response in plants can
provide information on the extent of bioavailability of
metals and their influence on the natural state of
aquatic ecosystem.
A significant aspect of this lagoon is a series of events
that might have occurred during the last four decade.
Assessment of ecological risk by determination of heavy
metals in benthic sediment and investigation of
physiological response against heavy metals in
Avicennia marina leaves is the main objective of this
study. A. marina is the only mangrove species found
throughout the Rabigh lagoon.

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Martensson
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 Materials and methods
1. Study area
2. Experimental design and sample collection
3. Preparation of samples
4. Determination of heavy metals in plants and sediments
5. Determination of heavy metals in plants and sediments
6. Determination of sediment pollution
7. Ecotoxicological risk
8. Bioaccumulation of metal in mangrove
9. Analysis of antioxidant enzymes in mangrove A. marina
10. Data analysis

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Martensson
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Conclusions:
1. A. marina was evaluated in this study in relation to possible stress caused by heavy
metals in eight stations investigated at the Rabigh lagoon, Red Sea.
2. There was a significant correlation between heavy metal concentrations in A. marina
leaves and mangrove ecosystem sediments, except for Cu and Cd. This is an indication of
fluctuation in the bio concentration factor of both plants and sediment.
3. In total, the results of our findings established deterioration of the sediment in a gradual
pattern which has a potential for negative impacts on the biogeochemical cycle, with
potentially lethal consequences for biodiversity survival. Consequently, there is a need for
periodic and regular monitoring of the pollution status in this ecosystem, through the use of
biochemical markers in the mangrove A. marina

40. Laws and regulations for
heavy metals

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Martensson
• There are various laws and regulations in place to control the
release of heavy metals into the environment. These include;
• the Clean Air Act, the Clean Water Act, the Resource
Conservation and Recovery Act in the United States. The Clean
Air Act and Clean Water Act are two laws that specifically
regulate heavy metal emissions and discharges into the
environment
EPA sets limits on the amount of heavy metals that can be
present in drinking water, air, and soil.
Heavy metals
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Martensson
Heavy metals EPA
As 0.01
Pb 0.015
Cd 0.005
Cr 0.05
Hg 0.002
Zn 5.0
Cu 1.3
Permissible limits(ppm) in drinking
water
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43. Jens
Martensson
• The European Union also has regulations in place to control the
release of heavy metals, including the Heavy Metals in
Fertilizers Regulation and the REACH Regulation. These laws
and regulations are intended to protect human health and the
environment by limiting exposure to heavy metals, which can
have negative effects on both. The European Union has
regulations in place to limit the amount of heavy metals in
consumer products, including toys and jewelry, and sets limits
on heavy metal emissions from industrial sources.
Laws and regulations
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44. Jens
Martensson
• The Executive Body adopted the Protocol on Heavy Metals in
Aarhus (Denmark) on 24 June 1998. It targets three particularly
harmful metals: cadmium, lead and mercury. The Protocol aims
to cut emissions from industrial sources, combustion processes
and waste incineration.
• In 2012, Parties to the Protocol on Heavy Metals adopted
decision 2012/5 to amend the Protocol to introduce flexibilities
to facilitate accession of new Parties, notably countries in
Eastern Europe, South-Eastern Europe, and Central Asia. In
addition, they adopted decision 2012/6 to update guidance on
best available technologies (BAT), as contained in annex III.
Amendments entered into force on 8 February 2022.
Laws and regulations
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45. Jens
Martensson
• . In addition, they adopted decision 2012/6 to update guidance
on best available technologies (BAT), as contained in annex III.
Amendments entered into force on 8 February 2022.
• In 2013, the Minamata Convention on Mercury was adopted, a
treaty negotiated (UNEP). Building on the 1998 Protocol on
Heavy Metals, the Minamata Convention raised the profile of
mercury to the global level.
Laws and regulations
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46. Jens
Martensson
• The permissible limits for heavy metals in food and water vary
depending on the specific metal and the country or
organization setting the standards. For example, in the United
States, the Environmental Protection Agency (EPA) sets
maximum contaminant levels (MCLs) for certain heavy metals,
such as lead and arsenic, in drinking water. The European Union
has established maximum levels for a number of heavy metals
in food, such as cadmium in cocoa and chocolate products. It's
best to check with the relevant authorities in your country or
region for specific information on permissible limits for heavy
metals.
Laws and regulations
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47. Thank
You