This 2012 survey article looks at a selection of studies up to several decades old with varied methodologies. The conclusion (my paraphrase): Needs more research. Can we get a grant?
A further search hits a 2018 NatGeo summary Fact or Fiction: Can You Really Sweat Out Toxins?
…new findings, published [paywall] in the journal Environment International, show that even when we do excrete environmental pollutants through our pores, the amounts we can sweat out are minuscule… For most pollutants, they’re so low that they’re essentially meaningless, says Pascal Imbeault, who led the new study. Imbeault is an exercise physiologist at the University of Ottawa…
At most, Imbeault and his colleagues found, a typical person doing 45 minutes of high-intensity exercise a day could sweat a total of two liters a day—normal background perspiration included—and all that sweat would contain less than one-tenth of a nanogram of these pollutants.
To put that in perspective, “the amount in sweat is 0.02 percent of what you ingest every day on a typical diet,” Imbeault says. If you really pushed it on your exercise regime, you might release up to 0.04 percent of your average daily intake of pollutants.
What that means is that there’s no way you could sweat enough to get rid of even one percent of what you’ll eat in your food that day . …there are more effective ways to remove high levels of metals from the blood, such as chelation therapy. And you pass more BPA out of your body in urine than in sweat.
So, to remove toxins, drink water and urinate. This is GQ so I won’t suggest targets.