Some mulch is just very dark in color......not dyed at all. And I wouldn't be concerned about CCA treated wood included. It was removed from the household use market in 2003 and even before that, scraps, shavings etc. were considered hazardous waste and had to be disposed of at sites that handle those materials - I can't imagine anyone including it in a mulch product. The liability and possible expense/fines of doing so would be prohibitive if they were found out.

I would always get a soil test if I planned on growing edibles around a house.

Fair point about the likelihood of CCA contaminated mulch. It is specifically contrary to EPA code. CCA treatment is allowed, by exemption, but not if it ends up in a wood product that was not treated specifically for that products intended end use. CCA is not intended specifically for end-use in mulch.

I researched mulch colorants awhile back and posted some info here but I can't find it at the moment. The colorants they use are typically innocuous materials like iron oxide (rust) for browns and reds, and a different type of iron oxide is black. Carbon black might also be used (I don't know so I'll take dan's word for it). I don't believe modern carbon black is a toxic problem though. It is different from soot that gathers in a chimney which would probably have high levels of PAHs. Produced in a controlled environment, carbon black is almost pure carbon. One very common place it's used is printer toner.

In short, colored mulch shouldn't be a problem with your herbs.

Someone mentioned soil testing. If your house is actually newly built and it's on previously undeveloped land (farmland) I wouldn't worry about it. If it's an older house, particularly pre-1978, or built on land where older buildings stood, it would probably be a good idea to test for lead anyway. I can give you some pointers on that if you're interested.

The CDC has this to say about carbon black. It won't kill you straight out, but it's not good for you. I wear gloves when refilling printer toner (which is a mixture of carbon black and iron oxide).

https://www.cdc.gov/niosh/docs/81-123/pdfs/0102.pdf

Soil test for metals, pesticides. Its near the structure, and from the tar paper on the roof to the paint or masonry it has been running rain water and the leacheate from the structure into those beds.

"Soil test for metals, pesticides"

These soil tests are quite different from a basic soil analysis (pH, % of OM, nutrient levels) and generally quite a bit more expensive. Depending on the test done, you may also need to specify exactly what pesticide/contaminant you want the sample to be tested for. Different testing procedures are required for different materials or potential contaminants so one size does not fit all!

As tox mentioned previously, lead is really the only heavy metal of serious concern and even that is limited to certain urban conditions.

There are some metal self-test kits around. I think Osumex sells them for a surprisingly reasonable cost. I have no idea how well these work, nor to what extent they can be used quantitatively, and this certainly isn't an endorsement of their product, but you might want to check them and research them. One tests for incidence of a range of heavy metals, and others (which are perhaps more quantitative) are targeted at specific metals. I suspect these aren't an issue for this colored mulch, but there have been other questions in this forum expressing concern about heavy metals.

After reviewing the state of Washingtons heavy metal analysis report which is required before fert is sold in the state, I would look for Arsenic. Dioxins and Furans might be getting exotic.

The question was about colored mulch. There is no evidence that I can see in this situation why the OP's soil or mulch should be tested for any metals, other than possibly Pb as I mentioned if it is an older house. Or any other contaminants.

Why should standards for fertilizer impurities have any bearing on household mulch?

As for the carbon black: thanks for the link dan, and I will concede there is a potential health risk to this material or CDC and NIOSH would not have published limits for it. That said, they are primarily aimed at protecting workers who are around it all the time. NIOSH sets a permissible exposure limit in mg/cubic meter of air for breathable materials based on health effects (in this case, cancer from its PAH content). It is highly unlikely that using it to dye mulch is going to produce concentrations of particles in air around your house that are even within orders of magnitude of those worker safety limits. I'm no fan of dyed mulch but it is not a health risk.

"The question was about colored mulch. There is no evidence that I can see in this situation why the OP's soil or mulch should be tested for any metals, other than possibly Pb as I mentioned if it is an older house. Or any other contaminants.

Why should standards for fertilizer impurities have any bearing on household mulch?"

- Its the dyes usually that have the higher levels of crap from what I have been reading. There are no real controls, and as mulch, its going on the soil, albiet in an ornamental use.

If you have any links to what you have been reading, please share.

Fair point about carbon black in mulch. It's not as if you're going to be bathing in the stuff, and it certainly isn't going to be taken up by plants in a hazardous form. But it isn't great stuff to have around in large quantities.

I agree that the dye itself isn't a heavy-metal issue, though as noted, one might be careful about possible CCA contaminated mulch. Probably illegal, but anyone who would sell dyed mulch probably isn't too concerned about the environment.

Note that there is actually a certification process for quality mulches, done by the Mulch and Soil Council. So what you're looking for, or might try to establish, is whether this mulch was ever MSC certified. It's a voluntary industry standard, but it carries some weight.