NORFOLK, Va. — As floodwaters covered roads across Norfolk Tuesday, some people drove through them while others got out and walked right in. But health officials say once the rain stops, the biggest concern isn't always the water you can see — it's what's mixed into it. Marcia Snyder, an environmental health supervisor with the Norfolk Department of Public Health, said stormwater can pick up sewage, waste and other pollutants as it moves through neighborhoods and drainage systems. Floodwater can also carry chemicals from vehicles, homes and yards, creating hazards people may not realize they're walking through. "It can be contaminants from chemicals from automobiles… whatever type of paint thinners, things people have in their yards," Snyder said.