The toxins may include pesticide residues from nearby farms or lead paint that has flaked off ships over the years. The dredging process exposes the toxins to air, which may alter the chemistry of the toxins and may cause them to become more water-soluble and even more hazardous. Controlling Beach Cliff Erosion Attempts to control the erosion of cliffs along beaches, at best, have slowed down the process and, at worst, have actually accelerated the erosion. Covering the cliffs with plastic sheeting is generally ineffective because during severe storms when the sheeting is most needed it is often torn apart. Concrete coverings over eroding cliffs tend to erode as quickly as the cliffs they are designed to protect.
Seawalls are piles of rock and debris that are piled in front of the cliff.
The seawalls are designed to break up ocean currents and storm waves. However, unless the seawall is as high as the cliff and extends the entire length of the cliff, the sea will eventually erode behind the seawall and continue its destruction of the cliff. The best policy appears to recognize that shoreline cliff erosion is inevitable and to keep property development a significant distance away from the edges of the cliffs. As stated earlier, millions of people live near sea level. By the end of this century, rising sea levels could drown their homes and businesses, and force them inland.