I've been told that using plastic bags for disposal of cat waste is the official position of the State of California. I tried to find the actual policy statement online but failed. However, there are many sites with information concerning this issue. Following is some information from one of them. Although only sea otters are mentioned in this excerpt I have read that fresh water otters are also vulnerable to this parasite
"Scientists and researchers have recently discovered a correlation between Toxoplasma gondii and the decrease in the sea otter population off the California Coast. Since cats are the only creatures that shed the T. gondii parasite, through their feces, there seems to be a direct link. Don't Flush: Even if you use a "flushable litter," dispose of used litter, including feces and clumps by placing it in a plastic bag, tying tightly, and putting it in the garbage can. Land wastes, where your garbage will end up, are covered with soil and have membranes to prevent pollution of ground water."
When I change the entire contents of a litter box I use a large plastic garbage bag but in between I remove all solid waste and urine clumps at least once a day from each of our cat boxes and I use plastic bags from the grocery and other stores for this purpose. People also use them for picking up dog poo.
What are we supposed to do if plastic bags are banned? Are we to buy new bags for cat poo? That surely can't be the answer but I've yet to hear what the answer is by the "ban the plastic bag" people. This environmental issue needs to be addressed as there are a lot of cat owners out here who don't know what we are supposed to do: avoid plastic bags or save otters.