salt

By Bettye Tish

In ancient times salt was a valuable commodity for its use in food preservation, so valuable that Roman soldiers were sometimes paid in salt (ever wonder where the word “salary” comes from?). Nowadays, few people think about the story behind the humble salt shaker on their kitchen table. Even fewer people think about its environmental impact. 

Sources of Salt

Edible salt is harvested from mining or evaporating saltwater resources. Salt is mined by injecting water deep underground to dissolve the salt and then extracting the brine. The brine is then dried through heating and purified at a processing facility. Aside from ecosystem degradation and the risk of groundwater contamination or a cave-in, this is a minimally invasive mining process. However, salt mining and refinement is a very energy-intensive process, often powered by burning fossil fuels. 

Salt can be obtained using significantly less GHG emissions through the process of solar evaporation. The solar evaporation of seawater into salt is a natural, slow process that requires a lot of land. Many speciality solar sea salts are harvested by hand and undergo very limited processing. Though this process has a minimal carbon footprint, it produces a by-product, bitterns, that can harm aquatic life in large amounts. 

Of the nearly 300 million metric tons of salt produced globally every year, only 6% reaches kitchen tables. The rest is used in everything from de-icing roads to manufacturing plastics. 

Many Salts, Many Environmental Impacts

But what makes Himalayan salt different from kosher salt or iodized salt? Here is a quick guide to what each type of salt means for sustainability…

• Iodized (table) salt - Contains iodide, an essential micronutrient. Iodide is often obtained from underground brine deposits during oil and natural gas mining. Although this brine can contaminate groundwater during extraction, only a very small amount of iodide is needed to enrich salt. 

• Sea salt - From evaporated sea water. Though very little energy is needed for its harvest, solar sea salt is rarely produced domestically and has many food miles. Large-scale sea salt evaporation ponds have been criticized for disrupting wildlife habitat. 

• Kosher salt - Distinguished only by coarse granules and a lack of additives. Depending on its sourcing, kosher salt causes environmental impacts associated with salt mining and carbon emissions from intense manufacturing. 

• Himalayan pink salt - Mined from Khewra Salt Mine in Pakistan. Though harvesting this salt lacks harmful chemicals, it still has the typical environmental concerns associated with salt mining and many food miles. Himalayan salt mining has also been criticized for unethical treatment of workers, who work in dangerous conditions often for less than $10 a day.

• Flake salt - Sea salt in a flattened, flakey form. If it is mechanically rather than naturally shaped it has a greater carbon footprint. 

Since all varieties of edible salt are made of the same mineral, NaCl, they can be used as substitutes for each other. For example, a recipe calling for 1¼  teaspoon of kosher salt can be made more green by using 1 teaspoon of sea salt instead. 

Don’t Go Low Sodium, Go Low Energy

Shopping for an eco-friendly salt is not as easy as looking for a sustainable certification on the package. In the United States, salt is considered a mineral by the USDA and cannot be certified organic. Try looking for salts that are “organic compliant,” meaning that they uphold the same organic standards (such as no additives). International quality certifications for salt, such as France’s Nature et Progrés, often signal low-energy production methods but such products rack up carbon emissions via high food miles. 

Aside from what is on the packaging, pay attention to the packaging itself. Many salts come in glass bottles, which are infinitely recyclable. Others are sold in containers primarily made of paper, which are lighter and take less energy to ship. Completely paper containers are compostable or recyclable; paper containers with a steel bottom can be recycled as well. 

To sum it all up, the next time you shop for salt, prioritize energy conservation by purchasing a less refined, solar sea salt. Bonus points if it is produced domestically! Whatever salt packaging you opt for, just make sure it ends up in the recycling or compost. 

Sources

• https://www.npr.org/sections/13.7/2014/11/08/362478685/from-salt-to-salary-linguists-take-a-page-from-science

• https://slate.com/technology/2010/03/are-some-kinds-of-salt-better-for-the-planet-than-others.html

• https://www.google.com/url?q=https://selectsalt.com/social/the-environmental-impact-of-himalayan-salt-harvesting-facts-and-myths/&sa=D&source=docs&ust=1710516029526001&usg=AOvVaw08Z-sMORasYKqdrD5TZBpO

• https://www.zmescience.com/feature-post/natural-sciences/geography/salt-extraction/

• https://mineralseducationcoalition.org/minerals-database/iodine/#:~:text=Relation to Mining,iodine is from this source.

• https://www.scirp.org/journal/paperinformation?paperid=119830

• https://selectsalt.com/social/the-environmental-impact-of-himalayan-salt-harvesting-facts-and-myths/

• https://www.thegoodloop.com/2022/02/25/the-environmental-impact-of-himalayan-pink-salt/

• https://www.cargill.com/salt-in-perspective/what-is-flake-salt-and-what-is-it-used-for

• https://www.bonappetit.com/story/kosher-salt-vs-sea-salt

• https://www.ams.usda.gov/sites/default/files/media/7 Salt and Preservatives FINAL RGK V2.pdf

• https://seasalt.com/salt-101/about-salt/organic-salt

• https://feedmrmurph.com/why-can-the-paper-container-with-a-steel-bottom-be-recycled-now/