Brian Altonen, MPH, MS

Equine Gastro-Intestinal Alkalosis; Bovine Ruminant-Gastro-Intestinal Alkalosis

Randolph Marcy noted that alkali water in the south pass area of Humboldt River, and along other southern routes, caused alkali poisoning.  His description of this is: 

“This disease first makes its appearance by swelling upon the abdomen and between the fore legs, and is attended with a cough, which ultimately destroys the lungs and kills the animal.”

The swelling of the abdomen is most likely due to a reaction between the alkaline material suspended in the water and the gastric acid in the stomach.  A similar reaction in cattle may be possible within the ruminant portion of the gut. Eructation and rumination together allow regurgitation-induced esophageal burning to ensue, depending upon the nature and acidity-alkalinity of the eructate/ruminate.  The more alkaline the imbibed streamwater is, the more likely eructation will result in inspiration of these fluids, thus resulting in a condition known as aspiration pneumonia.  And since this is an exothermic reaction, most likely internal thermal and chemical burning of the intestines, throat, and mouth can ensue, following by chemical damage of the respiratory tract once the regurgitated stomach/ruminant contents are aspirated. 

The key symptom to aspiration pneumonia is the eructation of pinkish to reddish froth from the respiratory passages and into the mouth.  This is an indicator that tissue damage has occurred due to the aspiration of a potentially damaging fluid.  Whereas normally this might be gastric-juice and the like, in this case it is either gastric acid, alkaline fluid from the stomach or ruminant, or aspirated alkaline water nearly directly into the lungs immediately upon ingestion.  In either of these cases, the consequences are such that   the liquid aspirated damages the lung tissue, damages the respiratory surfaces such as active alveoli, and causes scarring of the bronchioles and possible later onset of respiratory problems due to their closure or filling by blood and/or mucous. 

The bloating that ensues is most likely due to gas formation within a closed system–the gastrointestinal tract.  In the stomach, gas formation is from the interaction of carbonates and bicarbonates with gastric acid, in the gut it is from the slower-reacting carbonates, hydroxides, sulfur-rich minerals and perhaps other calcium binders.  Most will become potential gas producers due to their interaction with acids. 

The propensity of these conditions ensuing is not always evident upon viewing the waters.  Suspended particulates of carbonate-rich rocks such as limestone and gypsum (the slower-reacting intestinal-gas producer) are all that is needed to induce intoxication; neither may be visible as suspended particles.  The Gypsum and carbonates do lend a taste to the water though.  This makes it immediately evident, even to an unsuspecting emigrant, that the water is unsafe.  Other possible clues of unsafe water include the deposition of salts atop plants surfaces within the flood plains, especially those adjacent to the water, and the kinds of plants seen growing in th vitinity and their flavors when nibbled on.

Plants indicative of carbonate-ridden soil and waters include the ambitious pioneer weeds of the Pink Sub-Class (Caryophyllidae) within the Dicots.    Examples include various Docks (Rumex spp.), Amaranths, and Atriplex. 

Caught during its early stage, Marcy claimed this disease to be curable.  He recommends:

“The animal is first raked, after which a large dose of grease is poured down its throat; acids are said to have the same effect, and give immediate relief.  When neither of these remedies can be procured, many of the emigrants have been in the habit of mixing starch and flour in a bucket of water, and allowing the animal to drink it.  It is supposed that this forms a coating over the mucous membrane, and thus defeats the action of the poison.”

The head is drawn to the ground (“raked”), and grease introduced to the gut to hopefully prevent or slow the gas producing chemical reactions.  The reasons they suspected acids might work is uncertain; perhaps they cause the reaction well before the ingested toxin reaches a point in the intestinal tract where eructation is no longer possible. The starhc and flour formula, agains slows the reaction rate by interspersing itself between with the various reactant molecules within the gut.  The coating effect Marcy notes is possible, although temporary for the eosphagus.  Within the gut, it is perhaps slightly more effective against enabling severe injuries to ensue

Marcy provides an important clue to stream chemistry with his next sentences, in which he notes that Humboldt River has “less danger of the alkali” when the water is low.  He felt this was due to the feeding of Humboldt River by “pure mountain springs” during these periods of less rain, as well as the confinement of this bad water within the channel.  The high water levels on the other hand, he argues, due to rain cause the banks to overflow and thus allow water to escape the channel.  This in turn Marcy felt caused salts in the channel to dissolve into the water thus making it “more impure.”  Parts of Marcy’s statements are true.  More rain did mean higher waters and an increased likelihood that interaction would occur between water and nearby soil chemistry within the floodplain.  Yet, the more effective interaction would be the removal; of free, suspended Carbonate-nearing particulates within the soil, and the dissolution of free, unbound bicarbonates ready to form a gas after immersion.  The resulting change in chemistry was the development of an alkaline water due to the carbonates, which in turn was now more potentially damaging following ingestion.  In sum, a drought period, as was evident from ca. 1840 to 1948, left residual carbonate-producing material free-floating within soilbeds.  The ensuing heavy rains after 1848, redissolved this alkali into the water, made it harsher and thus more dangerous.  The incidence of this event can be seen in the trail diaries by recognizing the death of a horse, oxen or cow to fit the description of internal acid-base chemistry-induced gas-production, eructation, bloating, disorderly behavior, excitement, bellowing and then death.  The history of this as told by pioneers would appear in the diaries as accounts of bloated animals along the trail where they died.  A matter complicating this entire scenario, and perhaps making it more likely, is the changed foraging habits due to drought versus heavy rain periods, and due to the formation of vegetable bezoars, which could only increase the likelihood of intestinal blocking and then bloating.  Overall, the sensitivity of livestock depended upon various changes in weather, hydrology, soil chemistry and plant ecology along the Oregon Trail.