Veterinary Antibiotics in Agricultural Runoff in the BC Watershed

Posted on May 16, 2016

Image of livestock drinking from a typical watershed, a close relationship between antibiotics and their environmental impactDid you know that more than half of all antibiotics used in the world are used on farm animals? Though intended to improve the health and well being of livestock, these veterinary antibiotics are making their way into the environment through agriculture runoff, causing environmental and potential human health issues.  At CARO, we are constantly working on ways to provide our clients a better understanding of emerging contaminants of concern in BC’s Lower Mainland and across Western Canada.

This is the second recent post on the topic since focusing attention soil and water samples for antibiotics – read our first post about our expanded pharmaceuticals and personal care products testing capabilities here.

In this post, we will share with you details on a new CARO Technical Poster that was presented by two of our two members of our scientific team at the Canadian Trace Organic Workshop in Saskatoon, SK, titled “Veterinary Antibiotics in Agricultural Runoff in the BC Watershed”.


Veterinary antibiotics are used in the livestock industry to prevent and treat disease, and to improve growth and reproductive performance. These antibiotics can be found in animal excretions and have the potential to enter the aquatic environment when contaminated manure is used as fertilizer on cropland. Runoff from agricultural land into nearby aquatic environments creates a pathway for receptors to be exposed to antibiotics.

Scientists have found that as much as 90% of antibiotics administered to the animals orally may be excreted in urine or manure as an unchanged molecule (read more here).  Other than cropland application, pathways to the environment include the excretion of waste products by grazing animals, the accidental dispersion of feed and manure dust, or through the leaking of animal-water handling or storage equipment.

The CARO Approach

CARO watershed sampling region. For this project, water and sediment samples were collected at various locations throughout the agricultural area of the lower Sumas watershed. Using LC QQQ and EPA methodology, we tested for 24 antibiotics from 5 separate compound classes currently approved for use in agricultural practices.

NameFormulaClassVeterinary Use
MonensinC36H62O11IonophoresCattle, chicken, turkey
ChlortetracyclineC22H23ClN2O8TetracyclinesChicken, turkey, swine, cattle, sheep
TylosinC46H77NO17MacrolidesCattle, swine, chicken
LincomycinC18H34N2O6SLincosamidesSheep, chicken, duck, goat, turkey, cattle
SulfadimethoxineC12H14N4O4SSulfonamidesCattle, piglet, horse


What did we find?

The presence of the antibiotic monensin was found at several sites in both the water and sediment.  It is currently used for the prevention and control of coccidiosis, a disease affecting the intestines.  It is considered to be extremely toxic to humans and therefore not used as a human pharmaceutical.

The long-term effects of low-level concentrations as well as the effects of antibiotic-resistant bacteria on the environment are not known. Further year-round monitoring would be necessary to determine the full extent of this environmental issue.

Now What?

caro-order-now-buttonWith our extensive analytical testing capabilities, CARO is here to help better understand the chemicals in your food, soil or other environmental samples.  Visit our store to order a Pharmaceutical & Personal Care Products Testing in Water sampling kit today, that includes all the testing containers, sampling guidelines and results once the sample is submitted.

Do you have other questions? Please contact us anytime to discuss your analytical needs, including testing for antibiotics.


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