Sludge-based – or “reclaimed pulp” - beddings are made with fibers that are collected from pulp mill clarifier solids

Sludge is defined as a muddy or slushy mass, deposit, or sediment. In the case of pet bedding, it is the solid matter produced by water and sewage treatment processes. These types of pet beddings are made of “solids” discharged from pulp mill clarifier solids. Most pulp mills have an acid sewer and a basic sewer that blend together and dump into a large settling pond called a “clarifier.” The solids that are too small to make paper, combined with the “wash up water,” drain into the clarifier where the heavy particles settle to the bottom. These particles are then collected, screened to take out big chunks, “dewatered” through the use of a chemical flocculent, and then dried to create the bedding.

The color of the waste product varies with the different solids that make it into the sewer on a particular day, or because the sludge is collected from different paper or pulp mill products. The darker grey sludge is usually from the fly ash removed with the other exhaust pollution by scrubbers on the exhaust stacks.

Though the paper industry has made efforts to rid their waste streams of the most troubling compounds, tests conducted by independent laboratories (initiated by AWF) showed that detectable amounts of Dioxin remain in all samples of the reclaimed pulp paper beddings tested.

These tests showed that traces of Dioxin were present in gray and brown paper bedding products to a Toxic Equivalency Quotient (TEQ) of between 0.1 ng/kg (nanograms per kilogram) and 0.75 ng/kg. (A product with a TEQ of more than 0.75 ng/kg is considered unacceptable for human consumption.)

AWF took this testing to the next level when it asked the Michigan State University Diagnostic Center For Population and Animal Health (DCPAH) to review the test results. The reviewers said that the findings appear reasonable.

“Dioxin and dioxin-like compounds are considered to be ubiquitous, particularly in more industrialized nations,” wrote John P. Buchweitz, Ph.D., clinical toxicologist, and Andreas F. Lehner, Ph.D., analytical chemist, both from the Michigan State University Diagnostic Center For Population and Animal Health (DCPAH). They went on to state that: “Based on the findings of this limited initial study, it is important to note that pet beddings made with reclaimed pulp fibers are more likely to contain detectable levels of dioxin than wood shavings or byproduct papers.”

The review notes that DCPAH did not perform the testing on these products, and care should be taken in interpreting the results, and that “there is an inherent health benefit to minimizing cumulative dioxin exposures and such exposures should be avoided whenever practical.”

Drs. Buchweitz and Lehner conducted the review of previous testing of numerous small animal bedding products currently on the market. The tests, referenced previously, were performed using EPA (Environmental Protection Agency) Method 1613B, which “…is the EPA method of choice for Safe Drinking Water Act (SDWA) compliance testing and to meet the effluent monitoring requirements of the Pulp and Paper Industry,” states the review.

Buchweitz and Lehner also said, “We commend your company (AWF) for being proactive in limiting animal exposure to toxic polychlorinated debenzo-p-dioxins and –furans and feel certain that your ongoing monitoring program provides long term benefit to animal health.”