Which of the following is an example of a negative consequence of nonpoint source water pollution?

AIt is difficult to enforce laws which restrict nonpoint source water pollution.
BNonpoint sources of pollution are responsible for around 40% of river, lake and estuary pollution in the United States.
CNonpoint source water pollution only occurs in economically undeveloped regions.
DIt is difficult to prevent nonpoint source water pollution from running into point source water pollution.

Water pollution or water pollution is a modification of water, usually caused by human beings, which makes it improper or dangerous for human consumption, industry, agriculture, fishing and activities, as well as for animals.

Although water pollution can come from natural sources, such as the ash from a volcano, most of the current pollution comes from human activities.

The development and the industrialization suppose a greater use of water, a great generation of waste, many of which go to stop to the water and the use of means of fluvial and maritime transport that in many occasions, cause of pollution of the waters by your oil or fuel. Surface water is generally more vulnerable to anthropogenic pollution than groundwater, due to its direct exposure to human activity. On the other hand, a surface source can be restored more quickly than an underground source through seasonal runoff cycles. The effects on quality will be different for lakes and reservoirs than for rivers, and different for aquifers of rock or sand and sand gravel.

The presence of pollution generates what are called "forced ecosystems", that is, ecosystems altered by external agents, deviated from the situation of previous equilibrium forced to modify their operation to minimize the tension to which they are subjected.