More than 160 people, most of them children, have died in five villages across the northwest part of Nigeria as result of lead poisoning caused by illegal gold mining.

In March, residents of Zamfara State in Nigeria were poisoned when gold miners, without government approval, began crushing rocks containing gold ore to extract the precious metal. It was not known that the rock and soil contained high amounts of highly toxic lead, long known to cause serious damage to human nervous systems, especially in the young.

Children in the area were poisoned when they played with the discarded rock and soil.

A sad addition to the episode is that many more children than those initially exposed will suffer from the poisoning because it often takes time for the effects to show. In fact, lead poisoning can even be spread through breast milk to infants, showing itself in the form of serious nausea, convulsions, loss of coordination, loss of senses and eventually death.

Local officials believe about 300 people were poisoned but fear that number could grow if seasonal rains wash lead particles into neighboring water supplies and villages.

With the help of the U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO), Nigerian health authorities believe they have been able to contain the poisoning outbreak by stopping the mining and moving residents from the area.

Though one of Nigeria's poorest regions, Zamfara State is blessed with mineral wealth including large deposits of gold, copper, iron and sadly in this case, lead.

The most important issue at this point is getting aid to the affected and insuring how this type of calamity doesn't happen again. That may be difficult, however.

No evidence has been presented that suggests that either the government or the illegal miners knew of the hazardous conditions that existed there.

So unless the government invests in better environmental testing for rural regions of the country (I'm not going to hold my breath for that), there is no telling when the next crew of illegal miners searching for nothing more than riches and gold will find death and illness.