Factual error: At a stop on the Niger River, before they arrived in Mali, Dirk tells Dr. Rojas of "the angel wing clam" and calls them "Petricola Pholadiformis" and says that "this river is the only place on the earth they are found." Three problems: First, Petricola Pholadiformis are actually called "False angel wing" and are found many places in the world in fresh water (but seldom in the Niger River). Second, what's known as the "Angel wing" shell (no "false" in its name) has "Cyrtopleura Costata" as its scientific name. Cyrtopleura Costata ("Angel wing") is found in salt water. Third, Dirk also said they "glow in the dark"; some varieties of Cyrtopleura Costata shells will glow if exposed to ultraviolet light but none glow from their own internal source. Petricola Pholadiformis shells don't glow at all.
Factual error: While on the yacht on the Niger River, Dr. Rojas points out Asselar on a map. Asselar is about 150 miles northwest of where she points.
Factual error: While in Labbezanga, Dirk returns to the yacht and says "We're going upriver to Gao." When the buoy later detects something, and Dirk begins to call out the coordinates, "16-degrees 20-minutes North, zero." he gets interrupted by Rudi. The problem is that Gao is at 16-degrees 16-minutes north latitude; if they made it up to 16-20N they would have already passed Gao.
Factual error: Before meeting the Imam, Dirk and Al sat down on a table, discussing. On the background there was the sound of adzan, Islamic call for prayer. However, the adzan was completely wrong.
Factual error: Dr. Rojas throws the sticks of dynamite onto the sandbank that eventually reveals the ironclad ship. The explosions generated by the dynamite however are fantasy. Dynamite does not explode like a fuel flamed explosion as seen on screen.
Factual error: Dirk is fighting on top of the solar plant with the guy who attacked Eva at the start of the film. Dirk shot him in the hand with a spear gun. It doesn't matter how tough the guy, is he would not be able to hit Dirk with that hand without being in excruciating pain.
Answer: So they will not discover the poisonining that is going on.