Half of water samples test as unacceptable

SASKATOON — Water testing through the summer of 2017 found about half of Saskatchewan water sources sampled were unacceptable for livestock to drink.

Hot temperatures and dry conditions resulted in high levels of total dissolved solids (TDS) and sulfates in many locations. One extreme case of poor quality led to the deaths of more than 200 cattle in a community pasture near Shamrock.

Murray Feist, ruminant nutrition specialist at the provincial agriculture ministry, said 555 water bodies were sampled, including dugouts, wells, water lines, sloughs and other surface water sources. Sixty-two percent were dugouts, 13 percent were wells and the remainder came from the other sources.

Maximum acceptable limits are 5,000 milligrams per litre for TDS and 2,000 mg per litre for sulfates.

“About 40 percent of the dugouts in Saskatchewan had solids greater than 5,000,” Feist told the Saskatchewan Beef Industry Conference. “That’s a pretty high number.”

Sulfate levels were high enough that officials couldn’t recommend using about half of the water sources.

Feist said electrical conductivity is also a measure of water quality, although there is no value assigned to it for livestock use. But electrical conductivity can be used to calculate TDS and the two measurements then used to calculate sulfate levels.

He said the data from the 2017 samples are all over the place, from a high of 35,000 to an average of 4,900 microsiemens per centimetre, although he cautioned that the average doesn’t tell much.

However, Feist said that as electrical conductivity went higher, so did TDS.

Generally, TDS is considered to be 64 to 71 percent of the conductivity measurement. Dugout water tested in 2017 averaged 89 percent.

Each water sample is unique, however, and Feist said more work on the data is required. Sulfate levels in dugouts registered 41 percent of connectivity and were about 50 percent when sulfate levels were more than the maximum acceptable 2,000 mg per litre.

He told producers using handheld or desktop conductivity meters to assess water quality to be cautious. Some meters used in the 2017 sampling were more accurate than others and industrial meters measured more accurately against laboratory results.

“If you buy one, you have to test it and validate it against a known sample,” he said.

Given the dry conditions last year, and lack of snow in much of the south, producers should test water sources again this year before using them for cattle.

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