This is a striking image that pulls the viewer's attention to the center of the frame, eliciting in the viewer the same focused attention evident in the intent stares of the fishermen themselves. At first glance, the picture is enigmatic--it is not clear exactly what is happening or why. The text provided by the caption provides the crucial details, although the toxicity present in the scene remains almost incidental to it--effectively invisible to the viewer, blandly quotidian to those exposed to it. The effect is to remind us of the ways in which toxicity is subtly insinuated into everyday life, taking on a matter-of-fact character that makes it all the more insidious.
Scientists are constantly “measuring” toxicity, and a lot of times it’s the only way to prove toxicity. Sometimes the measurements even need to exceed a certain amount to be taken seriously. This visual talks about the toxicity captured by the senses as the author puts it. Our bodies can also “measure” toxicity.