Environmental chemistry is the scientific study of the chemical and biochemical phenomena that occur in natural places. Environmental science deals with ecosystem maintenance; by using the combined knowledge of the science fields that include the area of physics, geography, astro, biology and chemistry. Environmental Science & Environmental Chemistry in Contamination and Pollution Environmental Science & Environmental Chemistry in The Atmosphere Environmental Science & Environmental Chemistry in The water Environmental Science & Environmental Chemistry in The Soil and Rocks Environmental Science & Environmental Chemistry in The Trace Toxics

1. Difference Between Environmental Science & Environmental Chemistry
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Difference Between Environmental Science & Environmental Chemistry
Environmental Chemistry: - Environmental chemistry is the scientific study of the chemical
and biochemical phenomena that occur in natural places. It can be defined as the study of the
sources, reactions, transport, effects, and fates of chemical species in the air soil and water
environments: and the effect of human activity and biological activity on these.
Environmental chemistry is an interdisciplinary science that includes atmospheric, aquatic and
soil chemistry, as well as heavily relying on analytical chemistry and being related to
environmental and other areas of science.
▪ Environmental chemistry involves first understanding how the uncontaminated
environment works which chemicals in what concentrations are present naturally and
with what effects. Without this it would be impossible to accurately study the effects
humans have on the environment through the release of chemicals.
▪ Environmental chemists draw on a range of concepts from chemistry and various
environmental sciences to assist in their study of what is happening to a chemical species
in the environment. Important general concepts from chemistry include understanding
chemical reactions, and equations solutions, units, sampling, end analytical techniques.
▪ Environmental chemistry refers to the occurrence, movements, and transformations of
chemicals in the environment. Environmental chemistry deals with naturally occurring
chemicals such as metals, other elements, organic chemicals, and biochemical’s that are
the products of biological metabolism. Environmental chemistry also deals with synthetic
chemicals that have been manufactured by humans and dispersed into the environment,
such as pesticides, polychlorinated biphenyls (PCBs), dioxins, furans, and many others.
The occurrence of chemicals refers to their presence and quantities in various
compartments of the environment and ecosystems
▪ Environmental chemistry focusing only on the chemical aspects of the environment such
as chemical reaction happening; their mechanism; their composition; their quantity and
rate of it; its effects and sources on environment.

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Environmental Science: - environmental science deals with ecosystem maintenance; by
using the combined knowledge of the science fields that include area of physics, geography,
astro, biology and chemistry.
Environmental science is major field that can addresses environmental challenges by applying a
scientific knowledge in earth and environmental science, biology and chemistry can coupled
with the required selection of emphasis area.
For Example : The phenomena of earthquakes happen in environment can be explained by the
environmental science is as follows;
The geographical – distribution or, location from which it arise and where its felt could be
explained by the knowledge of geography. The phenomenon happens explained; by the
knowledge of physics. The environmental changes occur with it effects soil, water, atmosphere
composition could be explained by the chemistry and effect be biology.
Another Example: An – imagine chemical spill resulting from equipment failure. In this case
environmental science could examine this situation like;
i. Where will the spill go and what is the impact upon biological, chemical, & physical
system?
ii. What is the environmental risk of this spill to habitats, humans and animals?
iii. What will be long – term impact of this chemical spill on environmental system?
iv. How can I educate my community about this spill and its impact on environment?
v. How can my community prevent from this happening again?

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Environmental Science & Environmental Chemistry in
Contamination and Pollution
Contamination and pollution both refer to the presence of chemicals in the environment, but it is
useful to distinguish between these two conditions. Contamination refers to the presence of one
or more chemicals in concentrations higher than normally occurs in the ambient environment,
but not high enough to cause biological or ecological damages. In contrast, pollution occurs
when chemicals occur in the environment in concentrations high enough to cause damages to
organisms.
✓ A pollution result in toxicity and ecological changes, but contamination does not cause
those damages. Chemicals that are commonly involved in pollution include the gases
sulfur dioxide and ozone, diverse kinds of pesticides, elements such as arsenic, copper,
mercury, nickel, and selenium, and some naturally occurring biochemical’s.
✓ In addition, large concentrations of nutrients such as phosphate and nitrate can cause
eutrophication, a type of pollution associated with excessive ecological productivity.
✓ Although any of these chemicals can cause pollution in certain situations, they most
commonly occur in concentrations too small to cause toxicity or other ecological
damages.
✓ Modern analytical chemistry has become extremely sophisticated, and this allows trace
contamination of potentially toxic chemicals to be measured at levels that are much
smaller than what is required to cause demonstrable physiological or ecological damages.

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Environmental Science & Environmental Chemistry in
The Atmosphere
Nitrogen gas (N) comprises about 79% of the mass of Earth's atmosphere, while 20% is
oxygen (O), 0.9% argon (Ar), 0.035%, (CO), and the remainder composed of a variety of trace
gases. The atmosphere also contains variable concentrations of water vapor, which can range
from 0.01% in frigid arctic air to 5% in humid The atmosphere also can contain high
concentrations of gases, vapors, or particulates that are potentially harmful to people, other
animals, or vegetation, or that cause damages to buildings, art, or other materials. The most
important gaseous air pollutants (listed alphabetically) are ammonia (NH3), fluoride (F, usually
occurring HF), nitric oxide and nitrogen dioxide (NO and NO2, together known as oxides of
nitrogen, or NO), ozone (O3), peroxyacetyl nitrate (PAN), and sulfur dioxide (SO2).
• Vapors of elemental mercury and hydrocarbons can also be air pollutants. Particulates
with tiny diameters (less than 1μm) can also be important, including dusts containing
such toxic elements as arsenic, copper, lead , nickel, and vanadium, organic aerosols
that are emitted as smoke during combustions (including toxins known as polycyclic
aromatic hydrocarbons),and non-reactive minerals such as silicates.
• Some so-called "trace toxics" also occur in the atmosphere in extremely small
concentrations. The trace toxics include persistent organochlorine chemicals such as the
pesticides DDT and dieldrin, polychlorinated biphenyls (PCBs), and the dioxin,
TCDD. Other, less persistent pesticides may also be air pollutants close to places where
they are used.

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Environmental Science & Environmental Chemistry in
The water
Earth's surface waters vary enormously in their concentrations of dissolved and suspended
chemicals. Other than the water, the chemistry of oceanic water is dominated by sodium
chloride. (NaCl), which has a typical concentration of about 3.5% or 35 g/l. Also important
are sulfate (2.7 g/l), magnesium (1.3 g/l), and potassium and Calcium (both 0.4 g/l). Some
saline lakes can have much larger concentrations of dissolved ions, such as Great Salt Lake, in
Utah, which contains more than 20% salts.
a) Fresh waters are much more dilute in ions, although the concentrations are variable
among water bodies. The most important cations in typical fresh waters are calcium
(Ca ), magnesium (Mg ), sodium (Na ), ammonium (NH4+), and hydrogen ion (H ;
this is only present in acidic waters, otherwise hydroxy ion or OH occurs). The most
important anions are bicarbonate (HCO3
-) sulfate (SO4+2), chloride (Cl), and nitrate
(NO3). Some fresh waters have high concentrations of dissolved organic compounds,
known as humic substances, which can stain the water a tea-like color. Typical
concentrations of major ions in fresh water are: calcium 15 mg/l, sulfate 11 mg/l,
chloride 7 mg/l, silica 7 mg/l, sodium 6 mg/l, magnesium 4 mg/l, and potassium 3
mg/l.
b) The water of clean precipitation is considerably more dilute than that of surface
waters such as lakes. For example, precipitation at a remote place in Nova Scotia
contained 1.6 mg/l of sulfate, 1.3 mg/l chloride, 0.8 mg/l sodium, 0.7 mg/l nitrate,
0.13 mg/l calcium, 0.08 mg/l ammonium, 0.08 mg/l magnesium, and 0.08 mg/l
potassium. Because that site is about 31 mi (50 km) from the Atlantic Ocean its
precipitation is in influenced by sodium and chloride originating with sea spray. In
comparison, a more central location in North America had a sodium concentration of
0.09 mg/l and chloride 0.15 mg/l.

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c) Pollution of surface waters is most often associated with the dumping of human or
industrial sewage, nutrient inputs from agriculture, acidification caused by acidic
precipitation or by acid-mine drainage, and industrial inputs of toxic chemicals.
Eutrophication is caused when nutrient inputs cause large increases in aquatic
productivity, especially in fresh waters and shallow marine waters into which
sewage is dumped or that receive runoff containing agricultural fertilizers.
d) Surface waters acidified by atmospheric depositions commonly develop pH of about
4.5–5.5. Tens of thousands of lake and running-water ecosystems have been damaged in
this way. Acidification has many biological consequences; including toxicity caused
too many species of plants and animals, including fish.
e) Some industries emit metals to the environment, and these may pollute fresh and
marine waters.
f) For instance, lakes near large smelters at Sudbury, Ontario, have been polluted by
sulfuric acid, copper, nickel, and other metals, which in some cases occur in
concentrations large enough to cause toxicity to aquatic plants and animals.
g) Mercury contamination of fish is also a significant problem in many aquatic
environments. This phenomenon is significant in almost all large fish and sharks , which
accumulate mercury progressively during their lives and commonly have residues in their
flesh that exceed 0.5 ppm (this is the criterion set by the World Health Organization
for the maximum concentration of mercury intended for human consumption). It is
likely, however, that the oceanic mercury is natural in origin, and not associated with
human activities.
h) Many fresh-water also develop high concentrations of mercury, also commonly
exceeding the 0.5 ppm criterion. This phenomenon has been demonstrated in many
remote lakes. The source of mercury may be mostly natural, or it may originate with

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industrial sources whose emissions are transported over a long distance in the atmosphere
before they are deposited to the surface. Severe mercury pollution has also occurred near
certain factories, such as chloralkali plants and pulp mills.
i) The most famous example occurred at Minamata, Japan, where industrial discharges led
to the pollution of marine organisms, and then resulted in the poisoning of fish-eating
animals and people.
Environmental Science & Environmental Chemistry in
The Soil and Rocks
The most abundant elements in typical soils and rocks are oxygen (47%), silicon (28%),
aluminum (8%), and iron (3–4%). Virtually all of the other stable elements are also present in
soil and rocks, and all of these can occur in a great variety of molecular forms and minerals.
Under certain circumstances, some of these chemicals can occur in relatively high
concentrations, sometimes causing ecological damages.
▪ This can occur naturally, as in the case of soils influenced by so-called serpentine
minerals, which can contain hundreds to thousands of ppm of nickel. In addition,
industrial emissions of metals from smelters have caused severe pollution.
Soils near Sudbury, for example, can contain nickel and copper concentrations up
to 5,000 ppm each. Even urban environments can be severely contaminated by
certain metals.
▪ Soils collected near urban factories for recycling old automobile batteries can contain
lead in concentrations in the percent range, while the edges of roads can contain
thousands of ppm of lead emitted through the use of leaded gasoline.

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Environmental Science & Environmental Chemistry in
The Trace Toxics
Some chemicals occur in minute concentrations in water and other components of the
environment, yet still manage to cause significant damages. These chemicals are sometimes
referred to as trace toxics. The best examples are the numerous compounds known as
halogenated hydrocarbons, particularly chlorinated hydrocarbons such as the insecticides
DDT, DDD, and dieldrin, the dielectric fluids PCBs, and the chlorinated dioxin, TCDD.
These chemicals are not easily degraded by either ultraviolet radiation or by metabolic reactions,
so they are persistent in the environment.
▪ In addition, chlorinated hydrocarbons are virtually insoluble in water, but are highly
soluble in lipids such as fats and oils. Because most lipids in ecosystems occur within the
bodies of organisms, chlorinated hydrocarbons have a marked tendency to bioaccumulate
(i.e., to occur preferentially in organisms rather than in the non-living environment). This,
coupled with the persistence of these chemicals, results in their strong tendency to food-
chain/web accumulate or biomagnifies (i.e., to occur in their largest concentrations in top
predators).
▪ Fish-eating birds are examples of top predators that have been poisoned by exposure to
chlorinated hydrocarbons in the environment. Some examples of species that have been
affected by this type of ecotoxicity include the peregrine falcon (Falco peregrinus),
bald eagle (Haliaeetus leucocephalus), osprey (Pandion haliaetus), brown pelican
(Pelecanus occidentalis), double-crested cormorant (Phalacrocorax auritus), and
western grebe (Aechmophorus occidentalis). Concentrations of chlorinated
hydrocarbons in the water of aquatic habitats of these birds is generally less than 1 μg/l
(part per billion, or ppb), and less than 1 ng/l (part per trillion, or ppt) in the case of
TCDD.
▪ However, some of the chlorinated hydrocarbons can biomagnified to tens to

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hundreds of mg/kg (ppm) in the fatty tissues of fish-eating birds. This can cause severe
toxicity, characterized by reproductive failures, and even the deaths of adult birds, both of
which can cause populations to collapse.
▪ Other trace toxics also cause ecological damages. For example, although it is only
moderately persistent in aquatic environments, the insecticide carbofuran can accumulate
in acidic standing water in recently treated fields.
If geese, ducks, or other birds or mammals utilize those temporary aquatic habitats, they
can be killed by the carbofuran residues. Large numbers of wildlife have been killed this
way in North America.
Conclusion:
✓ From this discussion we can learn that the two terms environmental science and
environmental chemistry are two different terms, the environmental – science can deals
with the combined knowledge of science to maintain the environment that is ecosystem
(under the science facts phenomenon that explain by science).
✓ while the terms environmental – chemistry mean limited to the knowledge of chemistry,
to explain the facts happen in environment such as to study composition or formation or,
degradation of chemical or, substances involved in that phenomenon of environment( i.e.
reaction, formation, mechanism, elimination, sources, control, and alternate source to
eliminate or, form it if necessary).
Written By: Amir Hassan
Govt. Post Gradaute College Mardan KP Pakistan.
Comments To
Amirhassan741@gmail.com
The End!!!

10. Written By
Amir Hassan
Govt Post Graduate College Mardan KP Pakistan.
Comments To
Email: amirhassan741@gmail.com
https://www.slideshare.net/amirhassan27