Arsenic has deadly implications, from its ancient use as a poison to the ingredients in today’s pesticides and herbicides. Arsenic is a naturally occurring semi-metallic element from land to water to even the air. Inorganic arsenic is commonly present in groundwater in many US states at levels higher than recommended drinking water standards. Maine, New Hampshire, Arizona, and several other states are particularly prone to high levels of arsenic because of their unique rock formations. Arsenic-contaminated water is indeed an issue that needs to be addressed.
Read the details below on the risks of arsenic, how to test for arsenic in water, and how to remove arsenic from water.
What is Arsenic?
Arsenic is a toxic metal that occurs naturally in some soils and well water. Local industrial or mining activity can increase arsenic levels in well water. Arsenic is a highly toxic metal found in groundwater around the world. Groundwater is contaminated with inorganic forms of arsenic through natural sediments and various forms of pollution.
For example, pesticides can settle in nearby groundwater. Factories release excessive amounts of inorganic arsenic into the environment, and rainwater carries this arsenic into groundwater. Wells close to natural, industrial, mining, or agricultural deposits are particularly vulnerable to arsenic contamination.
Risk Associated with Drinking Arsenic Contaminated Water
Consuming excessive amounts of arsenic as per the EPA’s safe limit (currently 10 micrograms per liter or 10 parts per billion) can cause nausea, diarrhea, and skin disorders. When large amounts of arsenic are consumed over a long period, the metal can cause severe and chronic illnesses such as cancer and liver failure.
Drinking arsenic water may increase your risk of cancer, diabetes, and other serious health effects. Knowing how much arsenic is in your drinking water and how to reduce your exposure is important. To check the level of arsenic in drinking water, you need to test for it.
How to Test for Arsenic in Water?
It’s important to test the water to check its arsenic levels before treating it. The best way to test water is the use of arsenic testing kits. You can order these kits online and check your water quality by yourself. These kits are easy to use.
Although various arsenic test kits have different protocols to use, more or less, the same procedure is followed. Different reagents are given in the test kit in powder form. According to the instructions given on the kit, you need to add one or two reagents to the water sample and wait for 2 minutes at least. Then you have to add another reagent per instructions to the water sample, install a test strip into the turret cap, and tighten it. Wait for at least 10 minutes, and then remove the test strip to match its color with the reference chart. The Arsine reacts with the suspended test strip to form a color change from white to yellow or brown.
How to Remove Arsenic from Water?
There are the most effective ways of removing arsenic from water.
Reverse Osmosis Filter
Using a reverse osmosis filtration system is the most cost-effective way to remove arsenic from domestic water. Reverse osmosis can be considered filtration at the molecular level by using a special selective membrane. In this filtration system, water is forced through a special selective membrane. The membrane is microscopic, and its pores are specifically sized to accept water molecules. Larger molecules, including inorganic molecules such as lead and iron, chromium, and arsenic, are trapped on the membrane.
Research shows that RO is up to 95% effective in removing As (V). Most RO systems installed in homes are point-of-use (POU) systems. They are typically designed for production and use only a tiny amount of water, 2-3 gallons daily, usually kitchen sink. The system consists of a pre-filter that removes sand and grit membranes where RO occurs and an activated carbon polishing filter to help taste and odor control. Treated water is stored in a small tank and accessible from the faucet next to the regular faucet kitchen faucet.
Water softening systems are also called ion exchangers. The anion exchange system is a process that exchanges ions between the resin bed and running water. These systems soften water; remove iron and manganese, nitrate, and arsenic content. Water softeners are installed at the point of water entry in the house.
Mineral ions in the water supply are attracted to the resin bed, exchanging places with salt ions and leaving the water supply. A few ion exchange systems are equipped with special resin beds and use specific types of salts that can attract and remove arsenic ions. Conventional water filters are still useful in arsenic removal systems because removing high concentrations of hard minerals from the water supply enhances the effectiveness of reverse osmosis and KDF filtration.
KDF filters are one of the popular types of a cartridge filter that can be used to remove low to moderate levels of arsenic from well water. These filters use granular copper-zinc alloy media that react with certain dissolved metals in the feed water. This reaction causes an oxidizing effect that insolubilizes metal impurities. This allows the filtration system to extract arsenic and other metals using conventional screening stages easily.
KDF filter purification methods are suitable for filtering arsenic but tend to have lower performance and capacity than reverse osmosis filters. The KDF filter also deactivates when the cartridge becomes saturated with contaminants. This means that filter cartridges must be actively monitored and replaced to prevent arsenic from recontaminating the water supply.
Methods That Are Not Recommended for Arsenic Removal
Heating or Boiling Water
Primary water treatment methods such as boiling are unsuitable for removing dissolved metals such as arsenic. In fact, boiling of water can increase the arsenic levels in it.
UV irradiation is another effective method of disinfecting drinking water to reduce the health risks of pathogens. However, it does not affect arsenic.
Chlorine is the most common method used to reduce the risk of drinking water from microorganisms and some chemicals. However, in the case of arsenic, it is unaffected.
Carbon filters are the most common type of water treatment device for home use. Large GAC carbon filters can minimize arsenic levels but should not be considered an effective method of arsenic removal.
Excessive amounts of arsenic in drinking water are harmful to human health. If your water test result shows higher arsenic concentrations, you should opt for an effective filtration system for your home, as described in this guide.
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