Lawn chemicals, particularly those containing 2,4-D, have been linked to at least 2 types of canine cancers. The studies found that lawn chemicals travel to neighboring yards and inside houses, and chemicals have been found in the urine of dogs whose owners did not spray their lawns. The authors of the studies indicate how their findings can be used to further investigate human cancers.
A 6-year study from Tufts University School of Veterinary Medicine linked lawn pesticides to canine malignant lymphoma (CML). Based on the results of the questionnaire from dog owners, the study found that “specifically, the use of professionally applied pesticides was associated with a 70% higher risk of CML. The risk was also higher in those who reported the use of self-applied insect growth regulators. ”
A different study with similar methods found that herbicides also contribute to malignant canine lymphoma. The study found that herbicides containing 2,4-D doubled the risk of CML when dog owners used 2,4-D four or more times a year.
A study in 2013 concluded that 2,4-D herbicides and other lawn chemicals make the risk of canine bladder cancer “significantly higher”. Certain breeds, including Beagles, Scottish Terriers, Shetland Sheepdogs, West Highland White Terriers and Wire Hair Fox Terriers are more susceptible due to a genetic predisposition to bladder cancer. Exposure to chemicals can come from ingestion, inhalation or skin contact, and the amount of time needed to restrict pets from a sprayed area has not been determined.
The study found “Chemicals were detected in the urine of dogs in 14 of 25 households before the turf treatment, in 19 of 25 households after the turf treatment, and in 4 of 8 untreated households. Chemicals were commonly detected in grass residues from treated lawns, and from untreated lawns that suggest chemical drift from nearby treated areas. ”
Another study found 2,4-D herbicidal contaminants in the interior and in all houses, both before and after outdoor application. The study is evidence that pets absorb and track lawn chemicals, and lawn chemicals travel from their intended targets. The study concluded that “the elimination of shoes at the door and the activity level of children and pets were the most important factors affecting the levels of waste inside after application.”
Studies claim that they are important for the health of humans and pets. Non-Hodgkin lymphoma has a histology and epidemiology similar to CML, and has been linked to exposure to 2,4-D. 2,4-D has been localized to “possibly” cause cancer, and the agricultural use of 2,4-D has increased due to weed resistance.