So what IS in the water?   Leave a comment

Before we get started, I’d like to get some geographical clarification out of the way. So far you’ve seen me use both the terms “Coachella Valley” (where I am from) and “Imperial Valley.” Essentially, the Salton Sea is what separates these two areas from each other. The Imperial Valley is further to the east and south toward San Diego. Both are heavy agricultural areas.

The Salton Sea situated in between Coachella and Imperial Valleys

Now let’s talk about water!

Scientific literature on the Salton Sea is in no short supply. Which, I suppose makes sense, since it represents one of the very unique examples of a large aquatic environment in a very dry and water-stressed area. This creates some very intriguing ecological situations. One of the most important factors in the Salton Sea’s ecology is the water itself. So, we know that it’s salty–hence the name “Salton Sea”–but what else is exactly in that foul-smelling water that caused developers to flee in the late 60s?

Well, first off there is salt. Lots of it. Selenium is a big one too. Pesticides such as DDT and phosphates play a big role as well. But, to be honest, I can’t even begin to pronounce most of the pollutants that have been experimentally found in the water and sediment of the Salton Sea. So let’s break this down in a little bit more scientific detail.

The Salton Sea is a terminal body of water, meaning it has no outflow of water. It’s only water loss occurs through evaporation. So, all of the salts that come into the sea via rivers, channels, or runoff simply stay there. During times of intense heat and little rain or water inflow to the sea, water level decreases causing salinity to increase. As salinity increases, this causes a decrease in dissolved oxygen, making the water a less habitable environment for larger marine organisms. “The Sea’s salinity will gradually increase to about 60 g/L by about 2018,” according to the Future of the Salton Sea Report. The report also includes that “Salinity’s influence may be indirect, complicating predator-prey interactions and adding stress in environments with poor water quality (Williams, 1998).” Water from the Colorado River accumulates salts as it flows toward the Southwest. The salt content of the sea derives from salts already stored in the sediment as well as inflow of salts to the sea. A major source of these salts is agricultural wastewater that flows in through the New and Alamo Rivers. Agricultural runoff in the Imperial Valley empties into the rivers, which then flows into the sea. According to the Salton Sea Authority:

Currently, the salinity level of the Salton Sea is 44 parts per thousand (ppt), compared to 280 ppt for Utah’s Great Salt Lake, about 210 ppt for Israel’s Dead Sea, 87 ppt for Mono Lake and 35 ppt for the Pacific Ocean.

Increasing Salinity of the Salton Sea

Salinity is a critical problem for the vitality of the Salton Sea, but it is only the tip of the iceberg. A study performed in 2008 and 2009 concluded that “Mean total selenium concentrations in water for both sampling periods ranged from 1.00 to 33.6 micrograms per liter, predominantly as selenate.” (May et. al) That’s great data, but what does this selenium content mean? Selenium is a naturally occurring element that is essential at low concentrations, but in high amounts can be toxic to most wildlife. This handy rundown of selenium is in Pacific Institute’s Future of the Salton Sea Report from 2004.

In general, the presence of selenium is a concern because of:
•    its ability to bioaccumulate in the food web;
•    the narrow range between the concentration that is nutritionally beneficial and that which is toxic;
•    its effect on fish and bird reproduction and embryonic development;
•    its role in causing immune deficiency; and
• its effect on human health from consumption of contaminated fish and birds. (Fairbrother and Fowles, 1990; Setmire et al., 1993; Cohen, 2005)

So much for fishing in the Salton Sea! Sport fishery is still a viable activity in these waters, but it would be substantially dangerous to human health if any fish from the sea were commercially sold. The toxic selenium levels also cause harm to the migratory bird populations of the Salton Sea. Selenium measurements in Salton Wildlife are already at levels of concern, and inflow of more selenium will only compound the problem. Selenium is commonly used in the manufacture of glass and electronics. Most of the selenium of the Colorado River water comes from areas, such as the Green River Valley in Utah, that have high selenium content in the sediment. Farmers know that if this mineral is absorbed into the soil it will kill plant roots, so they water the fields with more than necessary water in order to cause removal of the selenium through underground drains. These drains lead to the Salton Sea.

Water flooding the fields to protect crops from mineral leaching into the soil

Remember in 1928, when Coolidge declared the Salton Sea an official Agricultural Sump? Well, here are some of the consequences of that action. According to a study in 2001 and 2002, current-use pesticides are present in the water and sediment of the Salton Sea in levels that cause toxicity in animals. Regarding dissolved pesticides, the study states that: “Generally, the compounds with the greatest concentrations and frequency were those pesticides applied in the largest quantities, and include atrazine, chlorpyrifos, dachtal, diazinon, eptam, malathion, pendimethalin, and trifluralin.” This sames study found high levels of DDE and other DDT metabolites. The levels of these chemicals were a close match to the levels of DDT detected in earlier studies, when the pesticide was still in legal use. The samples taken here prove that DDT metabolites persist and continue to be transported in aquatic environments. Another study also found notable amounts of PCB (Polychlorinated biphenyls) in Salton Sea water and sediment. Toxic effects of PCB can include endocrine disruption and neurotoxicity.

Image showing sample sites of LeBlanc et. al's experiment. The two river inflows to the Salton Sea are also shown.

The presence of these chemicals will likely cause–and probably already are causing–increased defects, diseases, and reproductive deficiencies of wildlife in the Salton Sea. However, the presence of harmful and unnaturally occurring pesticides in the Sea are not a concern for some. Local farmers of the $1.1 billion dollar agricultural industry in the Coachella and Imperial Valleys rely on this body of water as  place to dump their waste and runoff. According to John Benson, a second generation farmer near Brawley, “The purpose of the sea is to receive agricultural drainage. That’s what it’s there for.” According to a press-Enterprise article, 50 pounds of selenium water are dumped into the Sea due to agricultural waste water. According to the same article, 3 million tons of salt are poured into the sea each year as well. Agricultural pollution has been largely unregulated in comparison to point-source Industry pollution in the United States, in part due to a very strong agriculture lobby.

“Agriculture is the number one non-point source pollution problem in this country,” said Jovita Pajarillo of the U.S. Environmental Protection Agency’s California office (Polakovic)

Farmers could treat their wastewater before dumping into the Salton Sea, but this is a very expensive process. Wastewater treatment of agricultural runoff would cost more than Colorado River irrigation costs. No prudent businessman farmer would endorse the expensive treatment of this water when the unmonitored dumping of it into the sea has been a viable option for so many years. With this are providing a large percentage of the country’s winter fruits and vegetables, many people view the success of agriculture to be a priority over the health of the Salton Sea. I don’t mean to overly criticize these people or cast them as traitors to teh environment. They are simply trying to secure economic livelihood in a setting of outrageous agricultural productivity.To them, the Salton Sea is a convenient trash bin for their agricultural wastes. No one in the government is regulating them to do otherwise, so why not?

Runoff Wastewater on it's way to the Salton Sea.

I think it would take more than just wastewater treatment to make agricultural in the Imperial and Coachella Valley environmentally friendly. It would require a massive overhaul of the growing model, including techniques and produce that do not require such heavy pesticide and water use. The crops being grown in the valley are not naturally suited to teh environment, hence rely on copious amounts of irrigation water. Not only does valley agriculture have a negative effect on the Salton Sea, its reliance on Colorado River water causes major ecological changes downstream of canal diversion points. Beyond even that immediate effect, the transcontinental shipping of this produce causes further environmental degradation (Carbon emissions) in this highly unsustainable “breadbasket in the desert” model.

I wish I was done talking about the icky things in Salton Sea waters, but I am not. I haven’t gotten to the smelly part yet. Aside from the smell of dead fish (which I’ll get to later), hydrogen sulfide gas is the main contributor to the sea’s foul odor. Hydrogen sulfide emits a smell like rotten eggs, and is created by sulfate-producing bacteria as a byproduct of oxidizing the organic detritus of the Salton Sea. This bacteria may create around 78,000 tons of sulfide each year–that’s a lot of rotten eggs. Furthermore, “the sulfide strips available oxygen from the water and dissolved oxygen levels plummet, killing fish, invertebrates, and plankton.” (Cohen)

A "Green Tide," green gypsum crystals resulting from the oxidizaiton of sulfide into sulfate. These "green tides" correspond to sulfide-induced fish kills in the sea.

As is plainly obvious by now, much of the water content of the Salton Sea ties in with agriculture in surrounding areas. Since Colorado River water is heavily controlled and diverted to agricultural use, there are few other sources of water intake for the sea besides agricultural runoff. The intake of the Alamo and New Rivers is also heavily polluted with agricultural runoff. Control of agriculture is closely tied with the health of the Salton Sea. Reading scientific reports and analysis, as well as informed opinions, about the chemical contents of the Salton Sea has convinced me of quite a few things.

One, that the Salton Sea at its present state is not a fit site for long-term recreation. That is, any recreation that gets you close to the water. Birdwatching I could approve of. Thousands of visitors come to the Salton Sea each year, whether it is for sport fishery, bird watching, or just to see this odd inland see for themselves.  Drastic measures to clean of this toxic dump of a lake would have to be made for it to be safe for human use. Anyone looking bright-eyed to another potential resort city boom at the Salton Sea is grossly deluded. This sounds harsh, but I think that our  view of the Salton Sea as a waste container has severely damaged any future relationship with it as a recreational hotspot. I’ve grown up with the notion that the Salton Sea is kind of gross, and that notion has only increased after doing some research.

Two, the Salton Sea now appears to me as a perfect example where the manta of “rid pollution through dilution,” or however it goes, has gone horribly awry. The chemicals that have found their way into the Sea aren’t going anywhere soon–unless that ‘anywhere’ is lodged in the sediment of the lake bed.

Imperial Valley Field

Three, the agricultural habits of the Coachella and Imperial Valley need to change. Farmers should be held accountable for where they are depositing wastewater. Since the Salton Sea is a designated agricultural sump, this is not a problem at the moment. But I believe stricter regulation, as well as more sustainable and environmentally friendly growing practices could drastically improve the future water quality of the Sea, as well as help to decrease irrigation water used in the region.

Four, although I might not fully understand the ecology behind the contaminants in the Salton Sea (and neither do many scientists, I am sure) it is absolutely terrifying. Any body of water that constantly spits out dead fish is likely to play on the postapocalyptic imagination. I am not trying to say that the sea is a harbinger of death and destruction–there are still examples of successful abundant life within its shores. Yet, I am skeptical how much longer this can last given the current model of Salton Sea uses as well as its decreasing volume.

Coachella Valley Farmland near Indio

Sources:

Sapozhnikova, Yelena et al. Pesticides and PCBs in sediments and fish from the Salton Sea, California, USA. Chemosphere. 18 December 2003.

Cohen, Micheal and Hyun, Karen. The Future of the Salton Sea With No Restoration Project. Pacific Institute, Oakland: May 2006.

Polakovic, Gary. Farm Runoff: It’s an Ongoing Challenge. Press Enterprise. Accessed: http://www.sci.sdsu.edu/salton/FarmRunoff.html

May, T.W., Walther, M.J., Saiki, M.K., and Brumbaugh, W.G., 2009, Total selenium and selenium species in irrigation drain inflows to the Salton Sea, California, October 2008 and January 2009: U.S. Geological Survey Open-File Report 2009–1123, 14 p.

LeBlanc, L.A., Schroeder, R.A., Orlando, J.L., and Kluvia, K.M., 2004, Occurrence, Distribution and Transport of Pesticides, Trace Elements and Selected Inorganic Constituents into the Salton Sea Basin, California, 2001-2002: US Geological Survey Scientific Investigations Report 2004-5117, 40 p.

About The Salton Sea. Salton Sea Authority. Accessed: http://www.saltonsea.ca.gov/about/about.htm

Basic Information About Selenium in Drinking Water. EPA. September, 2011.  http://water.epa.gov/drink/contaminants/basicinformation/selenium.cfm#two

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Posted December 4, 2011 by jacqueline2014 in Biology and Ecology

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