Dust to Dust

5 comments

Leer en español

While there are many risks associated with the drying of the Salton Sea, perhaps the most concerning is the risk to public health. Previous posts on this blog discussed the health effects of dust from the Salton Sea, and that these health effects could end up costing around $29 billion. However, you may be thinking that these risks and costs are exaggerations or scare tactics. How could the dust from the Salton Sea make such a big difference when it is relatively small (343 square miles) when compared to the whole Salton Basin area of 8,360 square miles? Also, the majority of the basin is not covered by crops to reduce the wind erosion and transport of dust. So how can the drying of the Salton Sea which is approximately 3% of the total basin area, have such a disproportionate impact on the air quality? The answers to these questions lie in the composition of the sediment that lies below the Salton Sea.

However, we should first talk about the two measurements of airborne dust that are regulated by the U.S. Environmental Protection Agency (EPA): PM10 and PM2.5. The PM in these measurements stands for particulate matter and the numbers following them are the maximum diameter of the dust particles. For instance, PM10 is the mass of particles in the air with a diameter less than 10 micrometers. These diameters were chosen because particles less than 10 micrometers are small enough to travel into your lungs, and particles smaller than 2.5 micrometers can enter the bloodstream and cause the majority of the “haze” that leads to reduced visibility.[1] Therefore these two measurements are a good indicator of the potential health risks associated with dust, and in fact, Imperial County is already exceeding the EPA limits for these particulates.[2]

pm2_5_graphic_lg

Particle diameter sizes.
Obtained from U.S. EPA

So how will the drying of the Salton Sea cause PM10 and PM2.5 to increase so drastically that the health effects can add up to $29 billion?  The reason is the presence of salt, and more specifically, the type of salt in the sediment that will be exposed. A recent study by Buck et al. (2011) found that the type of salt forming a crust on recently exposed areas of the Salton Sea shore and its structural properties had a significant impact on the amount of PM10 emissions.[3] When minerals and environmental conditions are present that cause large salt crystals to grow, this generally forms a crust that will stabilize the soil and keep dust from being blown away. iMPerial-valley-dust-storm
A 2013 dust storm that impacted the Imperial Valley. Obtained from The Desert Review

However, at the Salton Sea, only small salt crystals are formed and these prevent soil aggregation, which destabilizes the soil and causes “…a continuous source of fine materials for dust emissions”.[4] This is one of the reasons why.the small area of the Salton Sea can have such a disproportionate impact on air quality and highlights the importance of maintaining water in the sea to prevent dust emissions. Luckily, the majority of the restoration plans keep this in mind, and several projects have been shown to successfully maintain habitat and perform dust abatement. However, action needs to be taken to implement these types of restoration before it is too late.

Written by Jaben Richards


[1] http://www3.epa.gov/airquality/particlepollution/basic.html

[2] http://www3.epa.gov/region09/air/imperial/index.html

[3] Buck B.J, J. King, and V. Etyemezian. 2011. Effects of Salt Mineralogy on Dust Emissions, Salton Sea, California. Soil Sci. Soc. Am. J. 75:1971–1985. https://dl.sciencesocieties.org/publications/sssaj/abstracts/75/5/1971

[4] Buck et al. (2011) As Above.

5 comments on “Dust to Dust”

  1. The dust is a huge problem. However, the destruction of the Pacific flyway is equally serious. Also, the sea is a visual feast. Aesthetics truly matter. Additionally, at least half of the variables in the California Environmental Quality Act have been seriously degraded thus far. They matter, too. Since the Sea lies in the Delta of the Colorado River, and thereby is subject to the public trust, the law requires consideration of these other factors.

    Like

    1. Thank you for your comment Mr. Cockroft. You bring up some interesting points. A few of which have been touched upon by previous posts (Bird is the Word), but stay tuned for more posts on these issues. Thank you for your passion regarding the Salton Sea.

      Like

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

w

Connecting to %s