Testing Water For Organic Pollutants: Methods And Techniques

Water is essential for life, but it can also be a source of harmful pollutants that can have serious health effects. These pollutants can come from a variety of sources, including industrial activities, agricultural practices, and even household waste. Testing water quality is crucial to ensure that the water we drink, cook with, and use in our daily lives is safe and contaminant-free. While there are many advanced laboratory methods available for water testing, this article will focus on low-tech, portable, and affordable field test methods that can be used by individuals and communities to monitor their water sources for organic pollutants.

Testing for heavy metals

Heavy metals such as lead, cadmium, and copper can be leached into the water supply from corroded pipes in the plumbing system. While this problem is more common in older homes with galvanized metal pipes, newer homes with corrosion-resistant PVC pipes may also experience corrosion as the pipes age. Therefore, it is important to test your water supply for heavy metals to identify the level of corrosion and determine if repairs are needed.

Consuming water with heavy metals can lead to cognitive illnesses and neurological problems. Heavy metal exposure can also cause unexplained fatigue, headaches, and digestive issues. Some essential heavy metals, such as iron, zinc, copper, and manganese, are necessary for human health but can be harmful in excessive amounts. Nonessential or toxic heavy metals like lead, mercury, cadmium, and arsenic have no biological function in the human body and can be harmful even at low levels of exposure.

There are commercially available test kits for detecting heavy metals in water, which typically use test strips or color disk tests. These kits are designed to be low-tech, portable, and field-testable, making them convenient for at-home use. However, it is important to note that at-home tests may not be as accurate or comprehensive as laboratory tests conducted by healthcare professionals.

To use a test strip kit, simply dip the strip into the water source for a few seconds and wait for it to change color. Then, compare the color of the strip to the provided color chart to determine the concentration of heavy metals in your water. Some kits may provide an eBook with additional information and instructions.

For more accurate and comprehensive results, consider sending your water sample to a certified laboratory for testing. Safe Home® offers a Metals in Water-Based Liquids Test Kit that can detect ten different metals. Their state-of-the-art instruments and rigorous quality controls guarantee precise and reliable results, with test results available within 7-10 business days.

Using test strips

Test strips are a low-tech, portable, and field-test method for chemical water quality monitoring. They are typically the most budget-friendly option, with test strips producing quick results. Some test strips may only test for one specific contaminant, while others can test for up to 20 different contaminants. They are small, single-use strips that change colour to indicate the concentration of a specific chemical. The user activates the paper or plastic strip by dipping it into the water sample, swishing it around, or by holding the strip in a stream of water. After a short wait, the user compares the colour of the test strip to a colour chart to determine the concentration of the chemical.

Test strips are extremely simple to use, but they are less accurate than other methods, especially if the user does not follow the instructions carefully. The readings are subjective, as the user must try to match the colour of the test strip to the printed chart. Outside conditions, such as lighting or colour blindness, can also make this task more challenging. Additionally, the tests are rushed, as the colour of the test strip continues to change even after it has been removed from the water sample.

Test strips are available for testing nitrate, iron, and manganese levels in water. Nitrate testing can help assess the impact of agricultural and human waste on water quality. High levels of nitrate are associated with agricultural pollution from fertilizers and animal waste. Iron and manganese can cause taste and odour problems, motivating consumers to seek out more appealing but potentially unsafe water sources.

There are also test strips available for testing lead levels in drinking water. These test strips provide a clear positive or negative result, indicating whether lead levels are below or above the EPA standard.

Colour disk kits

In a typical set-up, the user adds a powder packet or a few drops of a liquid reagent to a water sample in a reusable plastic tube. The user then places the sample tube in a small plastic viewing box. This viewing box contains a plastic disk with a colour gradient printed on it. The user rotates the colour disk to find the part that best matches the colour of the sample, and then reads the concentration of the chemical from the disk.

Monitoring for nitrate

Nitrate is a compound that occurs naturally but also has many human-made sources. It is present in some lakes, rivers, and groundwater. Consuming too much nitrate can be harmful, especially to babies, as it can affect how blood carries oxygen and cause methemoglobinemia, also known as "blue baby syndrome". This can result in serious illness or even death.

Test strips are small, single-use strips that change color to indicate the concentration of a specific chemical. The user activates the paper or plastic strip by dipping it into the water sample and swishing it around or by holding the strip in a stream of water. After waiting, the user compares the test strip color with a color chart to read the concentration of nitrate.

A nitrate electrode, used with a meter, consists of a probe with a sensor that measures nitrate activity in the water. This activity affects the electric potential of a solution in the probe, which is then transmitted to the meter and converted to a scale that is read in millivolts. The millivolts are then converted to mg/L of nitrate by plotting them from a standard curve. The accuracy of the electrode can be affected by high concentrations of chloride or bicarbonate ions in the sample water.

Testing for bacteria

Bacterial contamination of water can come from many sources, including waste, faecal matter, and insects that land in stagnant water. There are several methods to test for bacteria, but the plate count is the most reliable.

A water sample and a nutrient agar are placed and sealed in a clear dish. Agar contains substances that can help determine the type and amount of bacteria in the sample. After incubation for about 24 hours, colonies of bacteria will grow large enough to see with the naked eye. Analysts count the number of colonies on the plate.

There are also at-home testing kits available for purchase, which can provide results in as little as 24 hours. These kits can detect the presence or absence of coliform bacteria, including E. coli.

The pH level of the water can also indicate bacterial contamination. Drinking water typically has a neutral pH of 7, but certain bacteria will make water more acidic as they grow. You can test the pH of your water by adding a tablespoon of vinegar or bicarbonate of soda to a water sample and observing any changes in colour. If the pH of the liquid is acidic, the water will turn red or pink. If it is alkaline, it will turn green. A neutral pH will remain purple.

It is important to test water regularly for bacteria, especially if it is used for drinking, cooking, or bathing. The National Ground Water Association (NGWA) recommends testing private well water at least once a year.

Frequently asked questions