Yes/depends. Lead is still an issue but less common. Since the removal from most paints and gasoline, the incidence has dropped but the impact is still worrisome enough to be monitored. Random cases have emerged from kids gnawing on painted toys imported from overseas, home renovations, parents bringing home contaminated clothing for lead foundries. It can emerge in any ethnic/socioeconomic situation.
Yes. Lead paint in older buildings is still a source.
Yes they do. The major source of lead poisoning, is environmental, lead in residential housing, peeling paint inside and lead in the groundaround housing or where children play. Lead is a contaminant left from manufacturing sites.