Wednesday, 12 May 2021

Waste | Definition of Waste | Types of Waste | Sources of Waste


Waste (also known as rubbish, trash, refuse, garbage, junk) is any unwanted or useless materials. Waste is any substance that is discarded after primary use or is worthless, defective, and of no use.

Waste, also referred to as garbage or rubbish, is unwanted material that is discarded. 

Types of waste:

a) Chemical waste                                               

b) Biomedical waste 

c) Solid waste 

d) Liquid waste  

e) Gaseous waste  

f) Animal by-products

g) Special Waste 

Types of Waste

Sources of Waste:

a) Domestic waste

b) Commercial waste

c) Agricultural waste

d) Industrial waste

Sources of Waste

Sunday, 23 June 2019

Greenhouse Gases | Greenhouse Effect | Impact of greenhouse gases on environment


The term “greenhouse” was first used by Nils Gustaf Ekholm (Swedish meteorologist) in 1901. Greenhouse gases are surrounding the earth's atmosphere to prevent the loss of heat into outer space. These gases are essential to sustain life on earth.

Greenhouse Effect

The abundance of Greenhouse gases in the atmosphere due to anthropogenic activities are dangerous to life on earth:

The global community is facing the issue of increased concentration of greenhouse gases which have ultimate repercussions on human life and our natural climate.

Greenhouse Gases: CO2, CH4, N2O, Water vapors, etc

Global Warming

The UN climate conference of Paris agreed by I95 countries to reduce the emissions of CO2 and other greenhouse gases. The aim was to limit the global temperature below 2 ÂșC (relative to pre-industrial climate). According to Climatologists the increased concentration of greenhouse gases in the atmosphere due to human activities (burning of fossil fuel and deforestation) is warming the planet earth. These gases act in a glass of a greenhouse which allows the sunlight to enter and prevent the heat from escaping. The rise in atmospheric temperature is directly related to an increase in anthropogenic emissions of greenhouse gases. Water vapors, Methane, Carbon dioxide, Nitrous oxides, Ozone, and Chlorofluorocarbon are the most abundant greenhouse gases in the atmosphere whereas Chlorofluorocarbon is artificial gas. It is not found naturally in the environment. The percentage contribution of greenhouse gases includes water vapors (36-70%), carbon dioxide (9-26%), Methane (4-9%), Ozone (3-7%).

Impact of Greenhouse Gases on Environment: 

  • Impact on human life
  • Global Warming
  • Sea level rise
  • Economic Impact
  • Impact on Agriculture
  • Effects on Aquatic system
  • Effects on Hydrological Cycle

Control Measure of Greenhouse Gases:

  • Financing low carbon energy
  • Clean development mechanism
  • Green energy portfolio standard

Following initiatives are mandatory to reduce the effects of greenhouse gases:

  • Conservation of energy
  • Use of renewable energy
  • Reforestation
  • Methane gas recovery from solid waste
  • Banning of CFC production
  • National standards of pollutants
  • International conferences and seminars

Thursday, 20 June 2019

Ocean Acidification | Ocean carbon sink | Causes of Ocean Acidification

What is Ocean Acidification?

Ocean acidification occurs due to the change in ocean chemistry which happens due to the uptake of atmospheric chemicals like carbon, sulfur, and nitrogen. The anthropogenic release of carbon dioxide (CO2) is the dominant cause of ocean acidification while in several coastal areas, sulfur and nitrogen are also significant.

The ocean is a sink of Carbon:

The ocean absorbs atmospheric carbon dioxide (CO2).
Carbon capture and storage is called carbon sequestration.
Oceans capture and store carbon from the atmosphere.

Causes of Ocean Acidification:

For the past 200 years, the rapid increase in anthropogenic atmospheric CO2, which directly leads to decreasing ocean pH through an air-sea gas exchange, has been and continues due to the following reasons.
The rapid increase in atmospheric CO2 in the past 200 years due to anthropogenic activities is the leading factor in decreasing ocean pH due to air and sea gas exchange. The primary causes of ocean acidification are as follows.

  • Combustion of fossil fuel
  • Cutting of forest (Deforestation)
  • Industrialization
  • Production of cement
  • Land-use changes                                                                                           

How carbon dioxide (CO2) is the main cause of ocean acidification?  (Chemical reaction)

When CO2 dissolves in seawater, carbonic acid is produced via the reaction:

In seawater CO2 dissolves and form carbonic acid through the reaction below:

CO2 + H2O.................................  H2CO3

The carbonic acid splits in seawater and releases hydrogen ions and bicarbonate:

H2CO3......................................H+ + HCO3-

The increased concentration of hydrogen ions in seawater increases acidity in oceans. 

The result of the release of hydrogen ions in seawater is that it reacts with any carbonate ion and forms bicarbonate.

H++ CO 32--.................................H2CO3-

The above phenomena remove carbonate ions from seawater and it creates difficulty for aquatic organisms to form calcium carbonate (CaCO3) which is necessary for their shell formation.

Ocean Acidification

How aquatic life affected by ocean acidification? 

The ocean acidification affects some species of microscopic algae and calcifying plankton which are the base of marine chain and food for larger organisms i.e. fish and whales. The equilibrium chemical condition and pH level are important to build calcium-based shells and other structures for many seawater organisms like clams, mussels, sea urchins, microscopic plankton, etc. Ocean acidification affects their growth, reproduction, and survival in such a particular environment.

 Ocean Acidification


The ocean acidification will diminish the ocean's capability to capture and store atmospheric carbon and it will severely affect marine life. If concrete steps will not take to curb ocean acidification then its repercussions will be felt by the global economy by disrupting the food chain. 

Tuesday, 18 June 2019

Groundwater Pollution

The earth’s 97.5% water is saline and only 2.5% is fresh water and 68.9% of the freshwater is locked in ice caps and glaciers and 29.9% of fresh water is found on the sub-surface. In developed countries, 95% population having access to safe drinking water and 90% population has sufficient sanitation facilities.  Almost 50% of the groundwater used in cities is obtaining from wells, boreholes, and springs. One fifty million population of Latin Americans and greater than 1000 million Asian are depending on groundwater. Groundwater contamination is a very noteworthy environmental concern of the time. Regardless of its importance, groundwater resource is not properly managing. There are various probable sources of groundwater pollution in cities including point, non-point, and linear sources. Point sources include industrial effluents, domestic sewage, and storm overflow, non-point sources include construction work, agriculture activities, and atmospheric deposition and linear sources are roads and sewer system. The groundwater contamination can be resulting from leakage of sewage. Anthropogenic activities such as agriculture, industrial, and municipality are responsible for discharging and recharging contaminants into groundwater. The groundwater quality deterioration resulting from leachate percolation mainly occurs during the monsoon season and escalating the diseases related to groundwater contamination. Groundwater contamination occurs mostly in the vicinity of landfill and municipal waste disposal sites and increasing the chances of percolation in aquifers. The presence of emerging organic pollutants can be well examined and analyzed in wastewater and surface water as compared to groundwater. Emerging organic pollutant's major source is wastewater whereas surface water carries its maximum load. Approximately 2.3 billion population across the world is suffering from diseases related to polluted water. Worldwide, approximately polluted drinking water and insufficient sanitation kill 1.6 million children below the age of five years, and 84% of them are residing in villages. Water contamination is the foremost health and environmental issue in Pakistan. The main sources of groundwater pollution in Pakistan are the discharging of waste effluents into water bodies by many industrial units including textile, fertilizers, pesticides, steel, dying chemicals, cement, leather, etc. In Pakistan 20-40 % of hospital beds are occupied by patients with waterborne diseases like diarrhea, hepatitis, typhoid, dysentery, cholera, etc.  One-third of all deaths occur across the country owing to waterborne diseases. Heavy metals present in drinking water can damage vital organs i.e. kidney, liver, and central nervous system. They also cause abnormality in blood composition. There is a dire need to cope with the issue by responsible authorities to protect the health of citizens.

Groundwater Contamination

Sunday, 16 June 2019

Effects of Acid Rain on Plants | Effects of Acid Rain on Aquatic Life | Effects of Acid Rain on Human Health | Effects of Acid Rain on Soil | Effects of Acid Rain on Buildings

Effect on Plants:

An acid rain damage plant leaves (Necrosis). It leaches the minerals or nutrients from the soil through surface runoff and affects the growth and development of crops and forests.

Effects of Air Pollution on Plants and Vegetables

    Harmful Effects on Aquatic Life:

  • Acid rain increases acidity in water bodies
  • It stops the hatching of fish eggs
  • It changes the population ratio of fish
  • It affects the ecosystem

Effects on Human Health:

Acid rain can cause Asthma and Bronchitis disease. In the atmosphere, both SO2 and NOx react to form fine sulfate and nitrate particles that can be inhaled into the lungs.

Effects on Soil:

Acid rain affects the chemistry of soil and the availability of minerals in the soil. Nutrients availability has a strong relation with soil pH. When the pH of water decreases metals solubility decreases. Acid rain leaches the mineral ions through surface runoff or it pushes deeper into the soil and finally plants roots cannot get minerals from deeper horizons of soil which affects their growth.

Effects on the Built Environment:

Calcium carbonate is the major component of marble and it easily reacts with sulfuric acid (transported by acid rains) and forms calcium sulfate according to the reaction:

CaCO3 + H2SO4 → CaSO4 + CO2 + H2O

Calcium sulfate (CaSO4) is a thousandfold more soluble in water than Calcium carbonate (CaCO3) due to which it is easily washed out by the rain.

Effects of air pollution on monuments

    Fig: Material removal from the artifact surfaces erases its characters.


Acid Rain is a very serious and dangerous issue facing the modern world. To cope with acid rain there is a dire need to reduce gaseous emissions (burning of fossil fuel), find alternative sources of energy, protect the resources and restore the damage done by acid rain.


Thursday, 13 June 2019

Acid Rain | Acid Rain Definition | How is acid rain formed?

Acid Rain Definition:

Acid rain is any form of precipitation that is unusually acidic (elevated level of hydrogen ions) due to anthropogenic gaseous emissions in the atmosphere. Acid rain contains acidic components such as sulfuric acid and nitric acid.

Acid Rain

Brief History of Acid Rain:

The term acid rain was coined by Robert Angus Smith (Scottish pharmacist) in Manchester, England in 1872. He noticed a high level of acidifying rain falling over the industrial area of England as compared to less polluted areas near the coast. Little attention was given to his work until the 1950s when biologists observed the decline of fish population in the lakes of southern Norway and finally traced the problem of acid rain. Similar findings were also noticed in the 1960s in North America. These findings spurred intense research to understand the origin of the acid rain phenomena.

Measuring Acid Rain: (How it can be determined if rain is acid rain)

Acid rain is measured on a pH scale. Acid rain is one of the most serious environmental problems that emerged due to air pollution. Normal or unpolluted rainfall has a pH of 5.6 because carbon dioxide and water in the air react together to form carbonic acid, a weak acid.

CO2 + H2O............   H2CO3 (carbonic acid).

The term acid rain is applied to any type of precipitation with a pH level below 5.

Acid Rain Formation: 

Acid rain is the consequence of air pollution. When moisture of air reacts with oxides of carbon, sulfur, and nitrogen in the atmosphere to produce a mixture of carbonic, sulfuric, and nitric acids.

                   Acid Rain

  Acid Rain

Causes and Sources of Acid Rain:

  • Anthropogenic activities are the main cause of acid rain which includes the burning of fossil fuel.
  • The emission of gases from automobiles.
  • Burning of coal from Power plant 
  • The emission of gases from industries
  • Both Sulfur dioxide and Nitrogen dioxide are the major sources of acid rain formation.

Dry and Wet Deposition:

Wet deposition refers to fog,  acid rain, and snow. Wet deposition of acid rain affects a variety of plants and animals. Dry deposition refers to acidic gases and particles. Almost half of the acidity in the atmosphere falls back to the ground through dry deposition.

What is acid rain?

Waste | Definition of Waste | Types of Waste | Sources of Waste

Definition: Waste (also known as rubbish, trash, refuse, garbage, junk) is any unwanted or useless materials. Waste is any substance that is...