What often happens to rocks that undergo chemical weathering?

They will crumble easily. When they're worn on so much they start to break down.
Chemical weathering represents a second stage of rock disintegration in which small pieces of rock produced by physical weathering are then further broken apart by chemical processes.

Read more: Weathering - Chemical Weathering - Acid, Rock, Water, and Mineral - JRank Articles http://science.jrank.org/pages/7356/Weathering-Chemical-weathering.html#ixzz4hq1FAd65

He should put sand around the spill in order to contain it so that it won't spread

In some developing nations the percentage of the animal protein from fish in the diet can be as high as 25 percent.  about 85% of fish caught is used for human consumption.  the remainder is converted into fishmeal and fish oil.