The image is well composed, and the colours make it aesthetically pleasing. I don't know how it could be improved to extend its ethnogrpahic import. Although it could be a little sharper.
I don'y have any suggestions to enrich the image, I think it communicates a lot as it is. If the presence of the figures taking the photographs was to be highlighted, perhaps the contrast could be increased. But that could take away from the focus of the photo and the caption, which is on the river, toxicity and the algae.