MONITORING environment USing BIOLOGICAL AND CHEMICAL INDICATORS
The number of different species in an ecosystem.
Indicators that assess the quality of water, such things as dissolved nutrients, and dissolved metals.
Organisms that indicate the quality of water, this includes fish, plants, worms, insects, plankton (microscopic algae and tiny animals), protozoa, bacteria and viruses.
Microscopic organisms like bacteria can cause serious health problems when present in large enough numbers.
pH Affect on Aquatic environments
Are animals without backbones that live in water
These organisms are used because they indicate different conditions of the water, for example, oxygen levels, temperature and pH.
Diversity of organisms decreases as pH increases and dissolved oxygen decreases.
MONITORING WATER QUALITY
Cloudiness in lakes is caused by increase in algal growth, which reduces the oxygen content of the lake affecting organisms that live there.
Clarity is not a good indicator of water quality because some chemicals and organisms cannot be seen with the naked eye. Also some water is more turbid than others.
Water quality is determined according to the use of the water.
Different GUIDELINES FOR WATER QUALITY IN 5 CATEGORIES OF WATER USE INCLUDE:
Human drinking water
Recreation such as swimming
Livestock drinking water
Protection of aquatic life
CHEMICAL FACTORS THAT AFFECT ORGANISMS
These are most commonly monitored as indicators of water quality:
Algae grows on top of lake in warm temperature
Water and atmospheric oxygen are not in contact and can not mix.
Algae dies and the organic matter is now food for bacteria, decomposition uses up more oxygen. Oxygen decreases, fish and aquatic insects cannot survive.
From earlier, rain and snow have a normal pH of 5.6 because of CO2 in the air dissolving in them
As acidity increases, organisms decrease, for example, most fish disappear when the water’s pH fall to 4.5
3. Heavy metals (Hg, As, Pb)
Metals that have a density of 5g/cm3 or more, meaning they are 5 times or more heavier than an equal volume of water.
Includes mercury, copper, zinc, lead, cadmium and nickel.
These metals occur naturally and are made into everyday items like tires, batteries, and some fertilizers.
Affect the normal development in children, as well as causing permanent brain damage or death.
4. Plant and nutrients (N, P, K)
Runoff from fertilizers increase the growth of algae and green plants.
Some pesticides have long-term effects, but most are designed to last only one growing season, to be broken down by bacteria therefore are no longer toxic.
Many cause pesticide-resistant pests to develop and quickly, because of their rapid reproduction
6. Salts (NaCl, MgS)
SPRING ACID SHOCK :
When acidic deposits build up in ice and snow during winter. Once it melts in spring, the acid meltwater flows into aquatic systems lowering its pH level. This affects microbiological organisms, and increases how much heavy metal can dissolve in water.
PARTS PER MILLION...(YAY MATH)
MEASURING CHEMICALS IN THE ENVIRONMENT
Parts Per Million:
Measures concentration dissolved in a million units of a substance
use parts per million (ppm) or milligrams per litre (mg/L)
one part per million means that one unit of an element or chemical can be found in one million units of solution.
PPM = (Amount of Solute) / (Amount of Solution ) x 1,000,000
Solution = Solute + Solvent
1g water = 1ml water
If you had 25 pieces defective in a shipment of 1,000 pieces.
Then 25/1000= .025 or 2.5% of that shipment is defective.
Now calculate that percentage by one million. 0.025 X 1,000,000 = 25,000 PPM.
Suppose you make a food colouring solution by putting 99 mL of water in a beaker and adding 1 mL of food colouring.
The concentration of food colouring in this beaker is 1 part food colouring per 100 parts solution, which is 1% or 0.01.
Now calculate that percentage by one million. 0.01 X 1,000,000 = 10,000 PPM.
Suppose I have 100g of a salt solution, and the solution has 205 PPM of NaCl (Salt). How many grams of salt is there in the solution?
First write out 205 ppm in a g/1,000,000 format = 205g/1,000,000g.
Now multiply the ratio from step two by the amount of solution in step one. 100g x 0.000205 = 0.0205g
In the 100g of salt solution there is 0.0205g of NaCl present.
Note: parts per billion (ppb) and parts per trillion (ppt) exist but the use of special equipment is necessary and only extremely hazardous substances are measured to this level, for example PCB’s.
Invertebrates found in water are determined by the amount of dissolved oxygen.
5 mg/L (= 5ppm) of dissolved oxygen supports most organisms
LEVELS OF DISSOLVED OXYGEN DEPENDS ON many things:
Temperature, colder water holds more oxygen
Turbulence due to wind, speed of water flowing mixes water and oxygen
Amount of photosynthesis by plants and algae
Number of organisms using the oxygen
High concentrations of phosphorus and nitrogen affect the amount of dissolve oxygen.
Substances that produce serious health problems or death when introduced into an organism.
Example: Lead or Arsenic
Describes how poisonous a substance is.
A measurement used to compare toxins. LD means lethal dose, ‘50’ represents 50%.
LD50 is the amount of a substance that causes 50% of a group of test animals to die if they are given a specified dose of the substance all at once.
The more toxic a substance is, the lower the LD50 number is.
Different types of chemicals affect organisms in different ways:
Theobromine is found in chocolate:
LD50 humans : 1000 mg/kg
LD50 cats : 200 mg/kg
LD50 dogs : 300 mg/kg
This compares the toxicity of different substances because it is comparing the dosage that will produce death.
Question: If a bar of dark chocolate has 810 mg of Theobromine and your dog who weighs 5 kg eats it, what will happen?
MONITORING AIR QUALITY
Air quality is determined by:
measuring the levels of pollutants in the air
estimating the amount of emissions from pollution sources (forest fires, industrial plants)
SULFUR DIOXIDE (SO2)
Forms when oxygen combines with sulfur
Causes smog and acid rain
Affects the respiratory system (throat and lungs) and irritates the eyes
Sources include burning fossil fuels (coal, oil, natural gas)
Are used to reduce SO2 emissions by 99%. SO2 reacts with limestone that converts it to gypsum used in manufacturing.
NITROGEN OXIDES (NOX)
Formed when nitrogen monoxide gas (NO) reacts with oxygen to form NO2, a brown gas
Causes smog and acid rain
Affects the respiratory system (throat and lungs) and irritates eyes
Sources include combustion in vehicles, generating plants, industrial processes
CARBON MONOXIDE (CO)
Forms when there is not enough oxygen to produce CO2, it has no colour and no odour, thus called the ‘silent killer’
Affects the amount of oxygen content carried by blood cells, causing headaches, sleepiness, chest pains, brain damage and death
Sources include combustion in vehicles, wood, natural gas, industrial processes and cigarette smoking
GROUND-LEVEL OZONE (O3)
Carbon monoxide, nitrogen oxides and volatile organic compound (VOCs) (organic chemicals that evaporate easily) react with oxygen in the presence of heat and sunlight, to create a a colourless, odourless gas called Ozone.
Affects people who have lung diseases (asthma, even a cold!), breathing problems and long-term lung damage especially for developing children
Affects crops (wheat, soybeans, onion) and can causes rapid deterioration in plastic
Sources include fuel combustion in vehicles and industry
MONITORING THE ATMOSPHERE
Atmospheric pollution effects the entire globe!
A change in global or regional climate patterns
Atmospheric gas that traps infrared (Heat) from being emitted back into space
THE GREENHOUSE EFFECT :
Atmospheric gases in the air trap heat from the Sun’s radiant energy (we wan’t this to an extent)
A greenhouse effect out of control
With more gases trapping more heat, the Earth’s temperature is increasing
An increase in the average global temperature
Water vapour and CO2 are the 2 main contributors to global warming
Leads to climate change, violent storms, flooding and the spread of disease
Caused by human activities and natural events (volcanic eruptions, forest fires), increasing the concentration of greenhouse gases
THE OZONE LAYER
A layer of ozone (O3) gas that resides in the upper atmosphere surrounding Earth
Absorbs ultraviolet radiation (UV) protecting the Earth’s surface
Forms naturally 15 to 50 km above Earth’s surface
As the layer thins, holes can be created allowing more UV radiation through which is damaging to organisms
Chemicals made of chlorine and fluorine that reacts with UV radiation which ultimately destroys ozone
The chlorine atom in CFC’s will react with 100 000 ozone molecules
CFCs are found in refrigerators, aerosol cans, fire extinguishers
The hole over the South Pole was created because the ice particles in the atmosphere speeds up the reaction that destroys ozone molecules
Monitoring the ozone Layer
Keeping track of something for a specific purpose. Chemicals are monitored to protect our water and air quality.
READ THE FOLLOWING:
Write down words you don't know
Write down science vocab word you have already encountered
Harmful Substances Spread and Concentrate in the Environment
Chemicals know no boundaries! They Transport Through Air, Soil & Water…and borders!
Transport of chemicals in Air
The 3 stages of transport of substances in air are:
1.Release of the chemical from the source, chemical is dispersed into the atmosphere (the chemicals scatter in various directions
2.Direction and distance of airborne chemicals are determined by :
pollutant’s properties (Weight, size, and surface area of molecule)
wind’s speed and direction
3. Deposition of the chemical in soil or water
chemical Transport in Soil
Water carrying chemical substances can do 4 things in or on soil:
Evaporate - leaving chemical traces on top of the soil
Transpiration - soak into the soil, then be taken up by plants
Collection - flow over top of soil eventually collecting in streams/river
Form leachate - soak through the soil and move downward dissolving substances as it goes, carrying them along (this liquid is called leachate)
Water that has percolated through a solid (like soil) and leached out some of the constituents.
Composition of the soil affects the rate of the leachate’s movement
Ex. clay prevents leachate’s movement
Soils with a lot of organic material slows the movement of chemicals if they are absorbed by the organic material
Chemical Transport in Groundwater
Spaces between soil contains air and water, chemicals in water moves to the water table.
The top of the groundwater zone.
It then travels down to the groundwater (the next zone) where there is no air spaces.
Groundwater moves in all directions (sideways, up, down) and can move very slowly (1m per year) or very quickly (1m per day)
The tiny spaces between soil grains, if these are tightly packed, the groundwater containing the chemical moves slowly (clay particles are tiny, compared to sand)
Soil that contains interconnected pores which allows the quick movement of groundwater
Transport of Hydrocarbons in Soil
Hydrocarbons are carried by water in the soil
Hydrocarbons that do not dissolve coat grains of soil and fills up the pores in the soil, thus, concentration increases and also cleanup is difficult
Hydrocarbons are toxic to plants and animals (humans too!)
chemical Transport in Surface Water
Substances enter surface water from air, groundwater, runoff, outflow from sewers and sewage treatment plants
If the substance does not easily dissolve, it attaches to solids and will not travel very far and become more concentrated in the area
Substance are at the whims of ocean currents (ex. gulf stream)
Changing the Concentration of Harmful Chemicals in the Environment
The concentration of pollutants can be changed using different techniques:
The scattering of a substance away from its source
Reduces the concentration of a pollutant by mixing the polluting substance with large quantities of air or water
Dispersion and dilution may not meet government standards in leaving an area clean enough.
The breakdown of materials by organisms such as earthworms, and micro-organisms like bacteria, fungi, algae and protozoa.
Factors Affecting Biodegradation:
Means that an organisms needs oxygen for the process
Requires no oxygen for the process
A technique that can be used to reduce the concentration of harmful chemicals in soil and groundwater by the planting of plants that absorb or accumulate (build up) large amounts of chemicals from the soil.
The plants are allowed to grow absorbing the chemicals, then are harvested and burned or composted.
These chemicals include metals, hydrocarbons, solvents, pesticides, radioactive materials, explosives and landfill leachate.
The breakdown of compounds by sunlight.
For example, photodegradable plastic, it is made up of chemicals that when they react with sunlight, they turn the plastic into a fine powder.
Hazardous Chemicals Affect Living Things
Is the increase in concentration of a chemical or element as it moves up the food chain. (Remember bioaccumulation refers to the accumulation of toxic substance in animal over time, ex. a polar bear accumulates more toxins as it eats seals over time)
For example, if algae are infected with mercury, insects eat many algae, each obtaining amounts of mercury; fish eat many of the infected insects therefore obtaining even more amounts of mercury; and this continues up the food chain.
How hazardous chemicals affect living things is also seen in the Case Study:
Hazardous Household Chemicals
Hazardous household chemicals includes:
paint and paint products
personal hygiene products
pesticides and fertilizers
An average household has between 12L and 40L of hazardous products
These products can cause burns, heart, kidney and lung ailments, cancer, death.
Designed to protect consumers and reduce risks in transporting, storing, using and disposing of hazardous materials.
Workplace Hazardous Materials
Information System (WHMIS) :
Provides information on hazardous materials using symbols.
Material Safety Data Sheets (MSDs):
Detailed information sheets about hazardous products, provided by the manufacturer; includes:
description (its composition, physical appearance and chemical characteristics)
first aid treatment
There are different labels for different purposes:
Ex. transport, use in the workplace, supply and disposal
New Product Regulations
To place a new product in the market, companies must provide information including
physical and chemical properties
Instructions for use/safety precautions
Toxicity to humans
First aid instructions in case of poisoning
Storage and transportation of Hazardous Chemicals
Is relevant to prevent accidents and injury
Some examples include:
Leave in original containers
Make sure they have secure lids
Place in storage areas where they cannot fall over and spill
Store in cool, dry, ventilated places away from heat
Transportation of Consumer Goods
Hazardous materials should be placed in the trunk
Containers should stand upright and should not be able to move
Never mix chemicals together in one container
Should be left in original container when being disposed of
Disposal of Hazardous Chemicals
Never down the drain or into soil
Sewage treatment plants and septic tanks cannot remove these chemicals
Can contaminate drinking water, soil and air, and harm organisms if disposed of improperly
Hazardous Waste Collection Sites
These sites are used to dispose of hazardous wastes like paints and fertilizers
Materials not recyclable are labelled and sent to incineration plants