"People drunk water with elevated levels of lead"---Why is lead so bad for us? What does it cause

I've just seen this: http://ca.news.yahoo.com/brunswick-stude…

Why is lead so bad for us? What bad things does lead cause in our body?

Lead is a heavy metal which inhibits the action of essential metals in the body such as iron and copper. These metals have many functions which, when prevented, can lead to numerous complications. Acute lead poisoning can cause weakening of muscles, pins-and-needles and inflammation of the brain, which in turn can lead to headaches, nausea, vomiting and seizures. Chronic lead poisoning is associated with three main types of symptoms: gastrointestinal, neuromuscular and neurological. These include nausea, abdominal pain, slurred speech, headaches, loss of short term memory, anaemia and abnormal muscle movement. Exposure to high levels of lead can lead to kidney damage, high blood pressure and nerve damage. Clearly these complications can have fatal effects