It has not yet gone away

We had a major flood here in June after a period of widespread heavy rain. The river system could not handle the rain. The building in which I work was flooded almost to the ceiling of the ground floor. The leaves on the trees outside still carry a layer of river mud on them, indicating just how high the water came. That river mud was deposited everywhere the river touched. The river is filthy and contaminated with any number of unhealthy elements. Even now, almost two months after the flood, the subsequent rainfall has not been enough to wash the mud deposits from many places along the riverbank. The parking lot at work still has river mud on it, which means that I get contaminated river particles on my shoes every day. The disaster may have passed, but the health hazard is still present on the ground. I do not want that in my home, so I remove my shoes at the door and ask my guests to do the same.