Below is an image of a river with acid mine drainage flowing into it. Toxic Runoff
from a Mine
Riffle
Groundwater
This image shows how contaminated runoff can pollute a river and also
cause soil erosion
pollute groundwater
create algae blooms.
produce acid rain

the abdomen (less formally called the belly, stomach, tummy or midriff) constitutes the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. the region occupied by the abdomen is termed the abdominal cavity. the stomach secretes acid and enzymes that digest food. ridges of muscle tissue called rugae line the stomach. the stomach muscles contract periodically, churning food to enhance digestion. the pyloric sphincter is a muscular valve that opens to allow food to pass from the stomach to the small intestine.

the answer to your question is sperm