Both are charged with being accessories to a felony and destruction of evidence. Gold also is charged with removal of a body without authorization, said Sutter County sheriff's Lt. Butah Uppal.
DNA tests have shown the body parts belonged to McDonald's husband, Elmer McDonald, Uppal said.
Authorities aren't saying how or when Elmer McDonald died or whether anyone will be charged in his death.
Sutter County Sheriff J. Paul Parker said arrest warrants for McDonald and Gold were issued about three weeks ago, after investigators found a "considerable amount" of dried blood in April at the McDonalds' Sacramento mobile home.
"We've had them under surveillance since then," Parker told the Appeal-Democrat in Marysville, Calif. "This was complicated to trace this back the way it was."
The investigation began Nov. 22, when a severed leg was found in the river in southern Sutter County. Forensic pathologists determined the leg apparently was removed during a medical procedure.
Sutter County sheriff's deputies received a report of a possible body seen floating in the river south of Beer Can Beach on Dec. 11. A boat patrol didn't find a body.
On Feb. 26, a decomposed torso was found floating in the river in southern Sacramento County.
The grisly discoveries continued on March 13 when two fishermen found two decomposed arms down river from Beer Can Beach. The next day, detectives found a decomposed head in some berry bushes in the same area.
Sutter County sheriff's deputies said they initially contacted Gold on Nov. 15 after he was seen in the Beer Can Beach area with what appeared to be blood on his hands.
He told a deputy he was searching for a fishing spot and had cut himself in a fall. Gold, who had fishing gear in his truck, along with rope and plastic bags, was questioned briefly and given a warning about a broken license plate light on his truck.
Lela McDonald was being held at Sutter County Jail, while extradition was pending for Gold, who was being held at the Josephine County Jail in Oregon.