SANTA ROSA -- Nine-year-old activist and entrepreneur Vivienne Harr has joined an Oakland nonprofit to create a new brand of lemonade that aims to fight child slavery.

Harr, of Fairfax, has partnered with Fair Trade USA, the nation's largest fair trade certifier, to launch Make a Stand Lemon-aid, an organic bottled beverage that will be sold in grocery stores across the Bay Area. There's no price tag -- customers can pay what they choose for the lemonade -- and half of the profits go to organizations that work to end child slavery, including UNICEF, the Nepal Youth Foundation, the International Programme on the Elimination of Child Labor and Free the Slaves.

Harr will join Fair Trade USA to introduce the new line of lemonade at Molsberry Market on Sunday, 4-7 p.m., at 522 Larkfield Center in Santa Rosa.

Make a Stand Lemon-aid is the culmination of Harr's yearlong effort to raise money and awareness for the cause by setting up a roadside lemonade stand everyday, rain or shine. She raised more than $100,000 to donate to Not for Sale, a Half Moon Bay organization that combats human trafficking.

More information and lemon-aid at www.makeastand.com.

Contact Heather Somerville at 925-977-8418. Follow her at Twitter.com/heathersomervil.