Anne Johnson is a principal and vice president of global corporate sustainability with consulting firm Resource Recovery Systems.

And she believes developing nations, which are major contributors to ocean plastics, have plenty of work ahead before they can even consider an effective recycling program that would help keep plastics out of the oceans.

"Recycling is an advanced solid waste practice on the part of consumers. If consumers aren't really well-schooled in terms of collecting their trash, separating it, recycling is not something that is intuitive to them," she said at the recent Plastics Caps & Closures 2017 conference in Chicago.

"And in countries where you have really poor basic solid waste infrastructure, you often have consumers that don't also have good basic practice in solid waste management," she said during an interview at the conference. "You have to school them to that. I think that there is a learning curve. We've seen it in this country."

Attitudes and actions regarding solid waste marine debris is a hot-button issue around the world, but it's particularly challenging in developing countries in Asia that are viewed as major sources of ocean plastics.

"When we look at where a lot plastic debris comes from in the marine environment today, it's in countries that have very poor basic sanitation practices and essentially no recycling practices," said Johnson, who is the former director of the Sustainable Packaging Coalition. "So we really need to start on very foundational things there, building those landfills, building those practices and getting to recycling. That it also means working on basic solid waste policies and enforcing those policies.

"We need to get in the basic solid waste elements first," Johnson said at the conference sponsored by Plastics News.

An estimated 8 million to 12 million metric tons of plastics enter the oceans each year, Johnson said in a presentation at the conference.

Major sources of ocean plastics are Indonesia, China, the Philippines, Vietnam and Thailand.

Attitudes toward solid waste, recycling and littering result in people simply throwing their trash on the ground, which gets swept into waterways and then the ocean.

The Ellen MacArthur Foundation has been out front in bringing attention to the ocean plastics issue and has previously estimated that the equivalent of one garbage truck full of plastics finds its way into oceans every minute.

The foundation also estimated that there will be more plastic than fish by weight in the ocean by 2050 if current practices do not change.

Caps and closures, which can easily become separated from their bottles, are particularly dangerous for seabirds who see them floating and mistake them for food, Johnson said.

An estimated 90 percent of seabirds have plastic in their guts, she told the conference audience.