Joe Biden’s lead in the Democratic presidential race in Pennsylvania has fallen by 8 percentage points since October, according to a new poll of registered Democrats in the state.

The poll was released Thursday, five days before the Iowa caucuses begin the party’s nomination process and three months before the Pennsylvania primary.

Biden was the choice of 22% of registered Democrats surveyed, down from 30% in October, according to the Franklin and Marshall College poll.

In addition, former New York Mayor Michael Bloomberg debuted at 7% among Democratic candidates, after spending massively in the state. President Donald Trump’s approval rating ticked up despite his ongoing impeachment trial, and voters are closely split on an issue already being discussed in the presidential race in Pennsylvania: fracking for natural gas in Pennsylvania’s vast Marcellus Shale formation.

Pollsters interviewed 628 Pennsylvania registered voters from Jan. 20 to 26, and the results are subject to a margin of error of plus or minus 6.2 percentage points. Sub-samples of registered Democrats are smaller and subject to a higher margin of error.

Biden, whose campaign is based in Philadelphia and who often touts his Scranton roots, has argued that he is best positioned to beat Trump in Pennsylvania and other critical swing states in the general election.

His shift coincides with Bloomberg’s entrance into the race and a 3 percentage point gain for Vermont Sen. Bernie Sanders, the choice of 15% of Democrats polled, in line with his rise in other primary states. Massachusetts Sen. Elizabeth Warren, meanwhile, has dropped in the Keystone Poll from 21% in August to 14%.

Bloomberg debuts

In the two months since he entered the race, Bloomberg is already polling ahead of both former South Bend, Ind., Mayor Pete Buttigieg and Minnesota Sen. Amy Klobuchar.

Since announcing his run, he has averaged $1 million a week in television and radio advertising across Pennsylvania, according to data compiled by the ad-tracking firm Advertising Analytics. It’s an unprecedented $10.6 million investment in a state that won’t vote until April 28.

Bloomberg also opened a campaign field office in Old City and has 35 staffers already on the ground, with plans to scale up to 90 people in the state.

Bloomberg, who is self-funding his campaign, isn’t spending in the earlier voting states — betting that they will render split decisions and that he can do well on Super Tuesday, March 3, when about 40% of delegates will be allocated.

Impeachment hasn’t depressed Trump’s approval ratings

The impeachment trial in the Senate has done little to change how Pennsylvania residents feel about Trump. About two in five registered voters — 38% — believe he is doing an excellent or good job, up slightly from October.

Of respondents who approve of the president’s job performance, 83% said they’d vote for him no matter who runs against him. Conversely, three in five Pennsylvania voters said it’s time for a change. Of those voters, four in five (87%) said they’d vote against Trump no matter who becomes the Democratic nominee.

Pennsylvania is split on fracking

Pennsylvania residents are largely split on fracking, a contentious issue in the northeastern and southwestern regions of the state.

Proponents of fracking — natural gas drilling that uses hydraulic pressure to separate it from shale — emphasize that it has led to an increase in U.S. oil and gas production and created jobs. But the practice can cause contamination through groundwater and air pollution, among other concerns voiced by environmentalists.

Slightly more voters support (48%) than oppose (44%) fracking or shale drilling in the state. Opinion on whether fracking should be banned didn’t necessarily line up with opinion on the environmental risks. More people said they believe the environmental risks outweigh the economic benefits (49%) than the other way around (38%).

Support for a ban on fracking was highest in Philadelphia and Allegheny County. In the southwestern part of the state, where most of the fracking business is concentrated, only 28% of those polled said they’d support a ban, 55% said they’d oppose a ban, and 17% did not know.

Of the top-polling Democrats, Sanders and Warren want to ban fracking. Biden, Bloomberg, Klobuchar, and Buttigieg have said they want to limit or better regulate it. Trump, in Wildwood on Tuesday, said Democrats’ plans for a Green New Deal, which includes restrictions on fracking, would cost people jobs.

“Extreme liberals in Washington want to shut down U.S. energy, including through the so-called Green New Deal,” Trump told the crowd Tuesday. “Close your factories, get rid of your cows.”

Staff writer Andrew Seidman contributed to this article.