Shredded newspaper may also be used under other mulches in the landscape, where it is broken down by earthworms. Shredded computer or other office paper and glossy magazine-style paper decomposes slowly and may contain dioxins. There are enough concerns about the dioxin in bleached and glossy paper that it would be wise not to use them in the garden. Waxed paper almost never breaks down. There has been concern about using colored paper or ink, which contains heavy metals.
Many inks currently used are soy-based.
For similar reasons, in landscape plantings, cardboard or paper may be used under other mulches such as wood chips. In addition, there is the benefit of reusing paper products, which reduces costs and the need for their disposal in overcrowded landfills.