Unit C Lesson 5: Chemical Factors in Water Systems
Completion requirements
Unit C Lesson 5: Chemical Factors in Water Systems |
Learning Targets |
Big Question: Which chemical factors in water systems might affect the health and distribution of living organisms?
Almost 75% of Earth's surface is covered in water, and there's even more water underground and in the atmosphere. Chemicals in water systems can affect the health of many organisms directly and indirectly.
Almost 75% of Earth's surface is covered in water, and there's even more water underground and in the atmosphere. Chemicals in water systems can affect the health of many organisms directly and indirectly.
At the end of this inquiry, you should be able to answer the following questions:
- What is a biological indicator?
- How do I measure toxicity?
- How do excess phosphate and nitrogen affect a body of water?
- How does acidity affect water quality?
- What are heavy metals?
- Why is dissolved oxygen important to water quality?
Pages 213, 214, 215, 217 and 219 to 222 in your text will help you answer these questions about chemical factors in water systems
Introduction
Water is one of our planets most important resources. In fact, it is a resource that we cannot live without. Water monitoring is performed daily to protect humans, animals, crops, as well as organisms that live in or near aquatic environments.
Water must be tested frequently to ensure that water is safe to use for
In this section, you will study the factors that affect the quality of water.
- human consumption.
- livestock consumption.
- recreational activities such as swimming.
- irrigation.
- aquatic life.
Biological Indicators: Using Organisms to Measure Environmental Impacts
Environmentalists and biologists monitor the presence of certain organisms called biological indicators (also known as bioindicators) to provide important information about the water quality of aquatic ecosystems. Typically, unpolluted water contains a greater diversity of organisms than polluted water does. Polluted water supports larger numbers of tolerant organisms (organisms that have adapted to polluted waters) and have less diversity.
Environmentalists and biologists monitor the presence of certain organisms called biological indicators (also known as bioindicators) to provide important information about the water quality of aquatic ecosystems. Typically, unpolluted water contains a greater diversity of organisms than polluted water does. Polluted water supports larger numbers of tolerant organisms (organisms that have adapted to polluted waters) and have less diversity.
Figure 1 – Bioindicators. like the water strider are very sensitive to changes in their environment.
Aquatic invertebrates (animals without backbones) are monitored because they represent an enormous diversity of body shapes, survival strategies, and adaptations. Many invertebrates are sensitive to physical and chemical changes in their habitats.
Invertebrates cannot "escape" pollution and are collected easily from many lakes, streams, and rivers to determine the general health of water systems.
Many invertebrates require clear, cool water, adequate oxygen, and a steady source of food to complete their life cycles. These invertebrates, in turn, provide food for species that live in or near the water system, such as fish, birds, and frogs.
Various invertebrates prefer specific living conditions. The presence or absence of these "indicator" species can reveal the general health of the body of water.
Invertebrates cannot "escape" pollution and are collected easily from many lakes, streams, and rivers to determine the general health of water systems.
Many invertebrates require clear, cool water, adequate oxygen, and a steady source of food to complete their life cycles. These invertebrates, in turn, provide food for species that live in or near the water system, such as fish, birds, and frogs.
Various invertebrates prefer specific living conditions. The presence or absence of these "indicator" species can reveal the general health of the body of water.
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Water Quality
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Organisms Present
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Good water quality
(Presence of intolerant organisms indicates a healthy water system with little pollution.)
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Moderate water quality
(These organisms can tolerate moderate amounts of pollution.)
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Poor water quality
(Organisms that are very tolerant of pollution indicate poor water quality.)
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Percentages and Parts per Million (ppm)
In previous courses, you studied the meaning of percentage. Percent means the number of items from a sample of 100. Parts per million (ppm) is like percentage, but instead the sample is one million. In percentage, 25% means 25 out of 100. In parts per million, 25 ppm means 25 out of 1 000 000.
In previous courses, you studied the meaning of percentage. Percent means the number of items from a sample of 100. Parts per million (ppm) is like percentage, but instead the sample is one million. In percentage, 25% means 25 out of 100. In parts per million, 25 ppm means 25 out of 1 000 000.
For example: What percentage of the animals in Figure 2 are cats? (The sample size is 100 animals).
Figure 2 – Calculating parts per million; what percentage of the animals in this image are cats?
There are 2 cats among 100 animals (cats and dogs).
To find the percentage...
2% of the animals in the table are cats.
To find the percentage...
\[\frac{\text{number of cats}}{\text{number of animals}}\]
\[\times \]
\[100\]
\[\frac{2}{100}\]
\[\times \]
\[100\]
2% of the animals in the table are cats.
Pollutants and Parts per Million
In Unit B Lesson 2, you studied the components of a solution.
A solution is a type of homogeneous mixture.
Water is a vital source of life for all living organisms. When water is affected by pollution, all living organisms connected in the web of life are affected. A pollutant is any material or form of energy that can cause harm to living organisms. Pollution is the result or outcome of a pollutant or pollutants being introduced into the environment. Pollution is an alteration to the environment that produces a condition that threatens living organisms. Environmentalists lobby governments to develop policies that provide safety guidelines in terms of the acceptable level of various materials.
In Unit B Lesson 2, you studied the components of a solution.
A solution is a type of homogeneous mixture.
- solution – a mixture of one or more solutes dissolved in a solvent
- solute – the substance that dissolves to form a solution
- solvent – the substance in which a solute dissolves
Water is a vital source of life for all living organisms. When water is affected by pollution, all living organisms connected in the web of life are affected. A pollutant is any material or form of energy that can cause harm to living organisms. Pollution is the result or outcome of a pollutant or pollutants being introduced into the environment. Pollution is an alteration to the environment that produces a condition that threatens living organisms. Environmentalists lobby governments to develop policies that provide safety guidelines in terms of the acceptable level of various materials.
To determine if something is a pollutant , environmentalists must determine how much of it is present. Levels of a substance can be measured in
Parts per million (ppm) means the number of particles in a sample of one million (1 000 000). Parts per million (ppm) is used to measure the concentration of extremely dilute solutions. If there are 2 lead atoms in 1 000 000 parts of solution (which contains 999 998 water molecules and 2 lead atoms), there would be 2 parts of lead per million (1 000 000) parts of solution. Think about the entire population of Calgary, which has a population of about one million people. Imagine two people in Calgary were wearing lead suits. The lead suit ppm of people in Calgary would be 2 ppm.
The equation for ppm is similar to the equation for percent. When calculating ppm, you multiply by 1 000 000 instead of 100 (which you would with percent).
The equations for ppm are:
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ppt (parts per thousand) - how many particles of the pollutant can be found in 1000 particles of water.
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ppm (parts per million) - how many particles of the pollutant can be found in 1 000 000 particles of water.
- ppb (parts per billion) - how many particles of the pollutant can be found in 1 000 000 000 particles of water.
Parts per million (ppm) means the number of particles in a sample of one million (1 000 000). Parts per million (ppm) is used to measure the concentration of extremely dilute solutions. If there are 2 lead atoms in 1 000 000 parts of solution (which contains 999 998 water molecules and 2 lead atoms), there would be 2 parts of lead per million (1 000 000) parts of solution. Think about the entire population of Calgary, which has a population of about one million people. Imagine two people in Calgary were wearing lead suits. The lead suit ppm of people in Calgary would be 2 ppm.
The equation for ppm is similar to the equation for percent. When calculating ppm, you multiply by 1 000 000 instead of 100 (which you would with percent).
The equations for ppm are:
«math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mtext»ppm=«/mtext»«mfrac»«mtext»mL§#160;of§#160;solute«/mtext»«mtext»mL§#160;of§#160;solution«/mtext»«/mfrac»«mo»§#215;«/mo»«mn»1«/mn»«mo»§#160;«/mo»«mn»000«/mn»«mo»§#160;«/mo»«mn»000«/mn»«/math» OR
«math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mtext»ppm=«/mtext»«mfrac»«mtext»g§#160;of§#160;solute«/mtext»«mtext»g§#160;of§#160;solution«/mtext»«/mfrac»«mo»§#215;«/mo»«mn»1«/mn»«mo»§#160;«/mo»«mn»000«/mn»«mo»§#160;«/mo»«mn»000«/mn»«/math»
Finding ppm
Example
0.5 mL of food colouring is added to water to form 2 000 mL of solution. What is the concentration of the food colouring in ppm?
0.5 mL of food colouring is added to water to form 2 000 mL of solution. What is the concentration of the food colouring in ppm?
Answer
Remember that the solute is substance dissolving in the solution.
«math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mtext»concentration«/mtext»«mo»=«/mo»«mfrac»«mtext»mL§#160;of§#160;solute«/mtext»«mtext»mL§#160;of§#160;solution«/mtext»«/mfrac»«mo»§#215;«/mo»«mn»1«/mn»«mo»§#160;«/mo»«mn»000«/mn»«mo»§#160;«/mo»«mn»000«/mn»«mspace linebreak=¨newline¨/»«mspace linebreak=¨newline¨/»«mtext»concentration«/mtext»«mo»=«/mo»«mfrac»«mtext»0.5§#160;mL§#160;of§#160;solute«/mtext»«mtext»2000§#160;mL§#160;of§#160;solution«/mtext»«/mfrac»«mo»§#215;«/mo»«mn»1«/mn»«mo»§#160;«/mo»«mn»000«/mn»«mo»§#160;«/mo»«mn»000«/mn»«mspace linebreak=¨newline¨/»«mspace linebreak=¨newline¨/»«mtext»concentration«/mtext»«mo»=«/mo»«mn»0«/mn»«mo».«/mo»«mn»00025«/mn»«mo»§#215;«/mo»«mn»1«/mn»«mo»§#160;«/mo»«mn»000«/mn»«mo»§#160;«/mo»«mn»000«/mn»«mspace linebreak=¨newline¨/»«mspace linebreak=¨newline¨/»«mtext»concentration«/mtext»«mo»=«/mo»«mn»250«/mn»«mo»§#160;«/mo»«mi»p«/mi»«mi»p«/mi»«mi»m«/mi»«mspace linebreak=¨newline¨/»«/math»
Remember that the solute is substance dissolving in the solution.
«math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mtext»concentration«/mtext»«mo»=«/mo»«mfrac»«mtext»mL§#160;of§#160;solute«/mtext»«mtext»mL§#160;of§#160;solution«/mtext»«/mfrac»«mo»§#215;«/mo»«mn»1«/mn»«mo»§#160;«/mo»«mn»000«/mn»«mo»§#160;«/mo»«mn»000«/mn»«mspace linebreak=¨newline¨/»«mspace linebreak=¨newline¨/»«mtext»concentration«/mtext»«mo»=«/mo»«mfrac»«mtext»0.5§#160;mL§#160;of§#160;solute«/mtext»«mtext»2000§#160;mL§#160;of§#160;solution«/mtext»«/mfrac»«mo»§#215;«/mo»«mn»1«/mn»«mo»§#160;«/mo»«mn»000«/mn»«mo»§#160;«/mo»«mn»000«/mn»«mspace linebreak=¨newline¨/»«mspace linebreak=¨newline¨/»«mtext»concentration«/mtext»«mo»=«/mo»«mn»0«/mn»«mo».«/mo»«mn»00025«/mn»«mo»§#215;«/mo»«mn»1«/mn»«mo»§#160;«/mo»«mn»000«/mn»«mo»§#160;«/mo»«mn»000«/mn»«mspace linebreak=¨newline¨/»«mspace linebreak=¨newline¨/»«mtext»concentration«/mtext»«mo»=«/mo»«mn»250«/mn»«mo»§#160;«/mo»«mi»p«/mi»«mi»p«/mi»«mi»m«/mi»«mspace linebreak=¨newline¨/»«/math»
Watch
Watch a video to learn more about calculating parts per million (ppm).
Complete the three ppm questions to ensure that you understand how to calculate parts per million.
Example 1
Suppose a 125 mL sample of pond water is found to have 0.00017 mL of phosphates. What is the concentration of phosphates in ppm?
Suppose a 125 mL sample of pond water is found to have 0.00017 mL of phosphates. What is the concentration of phosphates in ppm?
Example 2
A 7.5 g of ground water was found to contain 0.00006 g of zinc metal. What is the concentration of zinc in parts per million?
A 7.5 g of ground water was found to contain 0.00006 g of zinc metal. What is the concentration of zinc in parts per million?
Example 3
The concentration of nitrates in a sample is 6 ppm. In how many millilitres of the sample would there be 6 mL of nitrates?
The concentration of nitrates in a sample is 6 ppm. In how many millilitres of the sample would there be 6 mL of nitrates?
Remember that the solute is substance dissolving in the solution.
mL of solute x 1 000 000
mL of solution
0.00017 mL x 1 000 000
125 mL
= 1.36 ppm
mL of solute x 1 000 000
mL of solution
0.00017 mL x 1 000 000
125 mL
= 1.36 ppm
Remember that the solute is substance dissolving in the solution.
g of solute x 1 000 000
g of solution
0.00006 g x 1 000 000
7.5 g
= 8 ppm
g of solute x 1 000 000
g of solution
0.00006 g x 1 000 000
7.5 g
= 8 ppm
Because the concentration of the solution is 6 ppm, there are 6 mL in one million (1 000 000) mL.
mL of solute x 1 000 000
mL of solution
6 mL x 1 000 000
1 000 000 mL
= 6 ppm
mL of solute x 1 000 000
mL of solution
6 mL x 1 000 000
1 000 000 mL
= 6 ppm
Water Quality
Water in freshwater systems (streams, lakes, and rivers) is not pure H2O but also contains both organic and inorganic compounds. Water from aquatic environments must be tested and monitored continually to ensure that the water is suitable for the organisms living in the aquatic ecosystem. You will study the following factors in this section to determine how each factor affects water quality:
Water in freshwater systems (streams, lakes, and rivers) is not pure H2O but also contains both organic and inorganic compounds. Water from aquatic environments must be tested and monitored continually to ensure that the water is suitable for the organisms living in the aquatic ecosystem. You will study the following factors in this section to determine how each factor affects water quality:
- dissolved oxygen
- plant nutrients (such as nitrogen and phosphorus)
- acidity (pH level)
- heavy metals (such as lead and mercury)
- pesticides
- salts (such as sodium chloride and magnesium sulfate)
Watch
Watch the following video carefully. It does an excellent job of reviewing the concept of chemical concentrations in the environment, and also discusses the implications for water quality.
Dissolved Oxygen and Water Quality
Dissolved oxygen (DO) is oxygen that dissolves in water. The oxygen dissolved in lakes, rivers, and oceans is crucial for the organisms living in it. The more dissolved oxygen in a water system, the greater the biodiversity. As the amount
of dissolved oxygen drops below normal levels in bodies of water, the water quality decreases and creatures begin to die.
The level of dissolved oxygen (DO) depends on
- temperature (due to change in seasons) The higher the temperature of the water, the less oxygen is able to dissolve.
- turbulence (due to wind or the speed of moving water) The more that water moves, the more oxygen from the air is able to mix with the water.
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photosynthesis of aquatic plants or algae. Oxygen is a product in photosynthesis. The more photosynthesis that occurs in a body of water, the higher the concentration of dissolved oxygen in the water.
- number of organisms using up the oxygen. Oxygen is consumed during cellular respiration. The more organisms in the water, the lower the concentration of dissolved oxygen.
There is a delicate balance between the number of plants and the amount of dissolved oxygen in a lake, river, ocean, or stream. Most of the plant material in an aquatic environment is algae. During the day, all plants use carbon dioxide and
give off oxygen as the plants undergo photosynthesis. At night, the opposite is true. Plants use oxygen and give off carbon dioxide as the plants undergo cellular respiration.
When bacteria decompose dead plants, the bacteria use up a large quantity oxygen and gives off a large quantity of carbon dioxide. When the amount of algae and plants in a body of water is excessive, large amounts of dissolved oxygen are removed from the water when the plants die and start to decay and rot.
Factors that affect concentration of dissolved oxygen (DO) in water
When bacteria decompose dead plants, the bacteria use up a large quantity oxygen and gives off a large quantity of carbon dioxide. When the amount of algae and plants in a body of water is excessive, large amounts of dissolved oxygen are removed from the water when the plants die and start to decay and rot.
Factors that affect concentration of dissolved oxygen (DO) in water
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Factors that increase DO levels |
Factors that decrease DO levels
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cool water temperatures
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warm water temperatures
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| turbulence |
stagnant water
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| photosynthesis |
cellular respiration
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plant decay
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Watch
Dissolved oxygen is essential for the health of aquatic life! To review what affects oxygen levels in a waterway, watch "Dissolved Oxygen Testing".
Nitrogen, Phosphorus, and Water Quality
In Lesson 1 of this unit, you learned that fertilizer contains nitrogen and phosphorus to help plants grow. Applying nitrogen to a plant promotes leaf and stem growth whereas phosphorus encourages root and flower growth.
Nutrient pollution is the process by which too many nutrients, mainly nitrogen and phosphorus, are added to bodies of water causing excessive algae and plant growth (commonly called an algal bloom). Why is this so dangerous for aquatic ecosystems?
Phosphorus and nitrogen are very important for all living things, but too much of either element can cause problems. Excess phosphorus and nitrogen come from:
In Lesson 1 of this unit, you learned that fertilizer contains nitrogen and phosphorus to help plants grow. Applying nitrogen to a plant promotes leaf and stem growth whereas phosphorus encourages root and flower growth.
Nutrient pollution is the process by which too many nutrients, mainly nitrogen and phosphorus, are added to bodies of water causing excessive algae and plant growth (commonly called an algal bloom). Why is this so dangerous for aquatic ecosystems?
Phosphorus and nitrogen are very important for all living things, but too much of either element can cause problems. Excess phosphorus and nitrogen come from:
Figure 3 – Sewage outfalls
Figure 4 – Runoff from fertilized fields
When levels of phosphorus or nitrogen increase in a body of water, rapid plant and algae growth occurs. The thick layer of plant material can cause sunlight to be blocked from reaching all levels of the water.
As a result, much of the plant and algae dies and bacteria that feed on the decaying plants and algae thrive and multiply.
As a result, much of the plant and algae dies and bacteria that feed on the decaying plants and algae thrive and multiply.
Bacteria that decompose dead organic material dramatically increase in number due to the large amounts of dead plant matter decaying in the water system.
Bacteria use up dissolved oxygen during cellular respiration, which leads to decreasing levels of dissolved oxygen.
Bacteria use up dissolved oxygen during cellular respiration, which leads to decreasing levels of dissolved oxygen.
Fish and aquatic insects cannot survive in water systems with low oxygen levels.
5 ppm or 5 mg/L of dissolved oxygen is needed to sustain most aquatic organisms. The higher the concentration of dissolved oxygen, the more variety of organisms is present in the body of water.
5 ppm or 5 mg/L of dissolved oxygen is needed to sustain most aquatic organisms. The higher the concentration of dissolved oxygen, the more variety of organisms is present in the body of water.
Watch
Watch the video "Nutrient Pollution" to fully understand the damaging affects of Nutrient Pollution. As you watch the video, name four possible sources of nutrient pollution.
- Farms
- Lawn fertilizer
- Pet waste
- Run-off from city streets
- Faulty septic systems
- Sewage treatment plants
Watch the video "Nutrient Pollution" to learn more.
Acidity and Water Quality
The optimum pH in a lake, river, or ocean is between 6.0 and 8.0. As a body of water becomes more acidic, less fish are able to survive. At a pH of 4.5, most fish disappear.
The acidity of rivers, lakes, and oceans can be affected by several factors:
The optimum pH in a lake, river, or ocean is between 6.0 and 8.0. As a body of water becomes more acidic, less fish are able to survive. At a pH of 4.5, most fish disappear.
The acidity of rivers, lakes, and oceans can be affected by several factors:
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photosynthesis of aquatic plants
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cellular respiration of aquatic organisms
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acid rain contact with minerals in rocks
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concentration of carbon dioxide
carbon dioxide + water → carbonic acid
When carbonic acid is produced, it increases the acidity (or lowers the pH) of the water.
Photosynthesis removes carbon dioxide from the water so when photosynthesis occurs in a water system, the pH of the water increases. As a result, the pH of the water becomes closer to neutral. This benefits a lake, river or stream since most freshwater systems tend to be acidic.
Cellular respiration produces carbon dioxide. When cellular respiration occurs in a water system, the water becomes more acidic and the pH decreases.
Acid rain also affects the pH of bodies of water. Acid rain describes any form of precipitation with a pH lower than 5.6. The precipitation can occur in the form of rain, snow, fog, and acidic dust material that settles to Earth.
In the winter, acidic snow falls and stays until the spring. When it melts, a large volume of acidic water flows into the rivers, lakes, and streams. For a short time, the pH of the river drops. This is called acid shock. The eggs of most aquatic animals and insects can be killed by the change in pH. This affects the whole food chain and ecosystem.
Acid precipitation causes major problems when the snow melts and flows into aquatic systems. Spring acid shock causes serious harm to the eggs and young offspring of fish. As the acidity of water systems increases (pH decreases), the diversity of organisms decreases! Most fish disappear if the water’s pH falls to 4.5.
In the winter, acidic snow falls and stays until the spring. When it melts, a large volume of acidic water flows into the rivers, lakes, and streams. For a short time, the pH of the river drops. This is called acid shock. The eggs of most aquatic animals and insects can be killed by the change in pH. This affects the whole food chain and ecosystem.
Acid precipitation causes major problems when the snow melts and flows into aquatic systems. Spring acid shock causes serious harm to the eggs and young offspring of fish. As the acidity of water systems increases (pH decreases), the diversity of organisms decreases! Most fish disappear if the water’s pH falls to 4.5.
Minerals found in rocks also affect the acidity of water. If rainwater comes in contact with limestone, sandstone, or chalk, the pH increases. The presence of limestone and other calcium carbonate rock in lakes and streams helps to maintain a constant
pH because the minerals react with and neutralize the acid deposition.
Watch
Watch the video "Water Quality Parameters" to review the factors that affect the water quality.
Pesticides, Toxins, and Water Quality
In Lesson 1 of this unit you learned about the advantages and disadvantages of using pesticides. Some pesticides have long-lasting effects because they do not break down quickly. As a result, they remain in the environment for long periods of time. Pesticides that are used now are designed to persist in the environment for only one growing season.
In Lesson 1 of this unit you learned about the advantages and disadvantages of using pesticides. Some pesticides have long-lasting effects because they do not break down quickly. As a result, they remain in the environment for long periods of time. Pesticides that are used now are designed to persist in the environment for only one growing season.
When pesticides enter waterways, they can become toxic to unintended organisms. Toxicity describes how poisonous a substance is. The term LD50 is used to identify how dangerous a toxin or poison is.
LD50 stands for “lethal dose, 50%”. LD50 is the amount of a substance that causes 50% of the test population (often rats or mice) to die if they are given a specified dose of the substance all at once.
LD50 stands for “lethal dose, 50%”. LD50 is the amount of a substance that causes 50% of the test population (often rats or mice) to die if they are given a specified dose of the substance all at once.
| Substance |
LD50 (mg/kg)
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sucrose (cane sugar)
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29 700
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sodium bicarbonate (baking soda)
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4 220
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sodium chloride (table salt)
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3 320
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acetyl-salicylic acid (Aspirin)
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1 000
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| antifreeze | 460 |
| caffeine | 192 |
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DDT (pesticide)
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87 |
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sodium cyanide
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6.4 |
A large LD50 means it takes a large quantity of the material to cause a toxic response. An organism would need to ingest a large amount of sugar to become ill because it has a high LD50 value of 29 700 mg/kg.
Small LD50 values are trouble! Small amounts of sodium cyanide are extremely dangerous because it has a low LD50 value of 6.4 mg/kg. In other words, a small amount is lethal.
Heavy Metals and Drinking Water
The term heavy metal refers to any metallic chemical element that has a density of 5 g/cm3 or higher and is toxic or poisonous at low concentrations. Examples of heavy metals include mercury (Hg), cadmium (Cd), arsenic (As), chromium (Cr), thallium (Tl), and lead (Pb).
The term heavy metal refers to any metallic chemical element that has a density of 5 g/cm3 or higher and is toxic or poisonous at low concentrations. Examples of heavy metals include mercury (Hg), cadmium (Cd), arsenic (As), chromium (Cr), thallium (Tl), and lead (Pb).
Heavy metals are found naturally in the Earth's crust. As trace elements, some heavy metals such as copper (Cu), selenium (Se), and zinc (Zn) are used to maintain the metabolism of the human body. However, at higher concentrations, heavy metals can lead to poisoning.
When ingested, heavy metals cannot be broken down or destroyed. To a small extent they enter our bodies through drinking water, air, and food. Heavy metal poisoning could result from drinking water from lead pipes, inhaling air with toxins from factories, or ingesting toxins through food such as mercury in tuna fish.
It is important to recycle batteries instead of throwing them in the garbage. Heavy metals can leak from batteries in landfills and enter the water supply.
Interactive
Water Pollution
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Click here
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