PORTLAND, Maine — The city’s 5-cent fee on single-use paper and plastic shopping bags and a ban on foam cups and containers go into effect April 15.

The amendments to the City Code require fees at grocery and convenience stores, pharmacies and farmers markets for paper or plastic bags used to carry out purchases. The fees will not be assessed on smaller bags, such as those distributed in produce sections.

Retailers will keep the money, which isn’t expected to cover their costs for reusable bags and new packaging.

“I want to do my part,” Moran’s Market co-owner Paul Larson said last week. “But margins are so thin as it is.”

The sale and use of polystyrene food containers and cups also will be banned at stores and restaurants, except for packaging of seafood.

The fees and ban were approved after a year-long study by a task force led by Councilor Ed Suslovic, who said the fees will be very easy to avoid. He added he would like to see polystyrene foam use eliminated throughout the city.

But James Tarsetti Jr., owner of Pine Tree Paper on Warren Avenue, said the ban could be costly. Paper cups can cost four times as much as foam, and substitutes for foam food trays could be almost five times more expensive.

“The convenience stores will probably take the brunt of this,” Tarsetti said. “A lot of their stuff is going to go up.”

He said he expects those costs to be passed along to consumers.

Polly Wanzer, manager of the Rosemont Market and Bakery on Brighton Avenue, is an enthusiastic supporter of the changes.

She said plastic bags and foam containers have never been used at Rosemont stores, where compostable utensils are distributed and hot soup is sold in lined paper containers.

On Munjoy Hill, Hilltop Superette manager Nate Philbrick said his store also is prepared for the changes.

“There may be a bit of pain in the beginning, but in the end it will be a good thing,” he said.

The store already uses compostable take-out containers and soon will offer its own reusable bags, Philbrick said.

Larson, of Moran’s Market on Forest Avenue in Riverton, said he uses about four cases per week of foam containers for hot foods. At best, he said, the bag fee could offset some of his increased container costs.

The rules were enacted as a way to reduce bags and containers from the waste stream and to eliminate a source of litter, but Tarsetti said a shift to paper-based food containers will not necessarily increase recycling.

“Once paper is food-contaminated, it just becomes landfill,” he said. “It cannot become office paper.”

Frank Gallagher, spokesman for the ecomaine regional waste disposal consortium, said that may be an oversimplification because recyclability depends on how much contact the food has had with the container.

“A great example is a pizza box,” Gallagher said. “If there is a little bit of grease, it is (still) recyclable.”

He also said nothing in the Portland trash stream becomes “landfill” because ecomaine burns solid waste to generate energy.

The foam containers are not recycled, Gallagher noted, and while plastic bags are they routinely clog up sorting machines.

“We have to periodically shut down, usually at the end of the day, to cut those things free,” he said.

The bag fees also will require store owners to reprogram cash registers, with a wrinkle that fees may not be charged to the electronic benefits transfer cards used by customers on public assistance.

Clark Street Deli and Market manager Phillip Vaillancourt said his customers use the EBT cards, and he already is hearing backlash.

“Some customers think we are doing it ourselves,” he said, so he has posted the city notice and is hoping he won’t lose customers.

The complications come on a larger scale at the city’s two Hannaford supermarkets, on Forest Avenue and Riverside Street.

“The polystyrene ban has been easier to address,” company spokesman Eric Blom said last month. The stores will no longer be selling foam coolers or cups.

In advance of next week’s startup, Hannaford also is giving away reusable bags through April 14. Blom said as many as 100,000 could be distributed.

Starting April 15, Hannaford’s reusable bags will be sold for $1.29 each; the company will donate 25 cents to hunger relief for each bag. Proceeds from the 5-cent bag fees also will be donated to local organizations that fight hunger.

Portland resident Virginia Fox, loading one of the new, reusable bags into her car last week outside the Forest Avenue store, said she supports the fee.

“It is working exactly the way it is supposed to,” Fox said. “People need the motivation.”