**4. Conclusion**

In this study, the levels of heavy metals showed significant variations only due to the climatic season; the dry season has a more significant influence on the increase in levels of all the metals included in this study. As discussed throughout the chapter, high temperatures in the area cause phenomena of evaporation, concentration, and precipitation of pollutants from the water column to the sediments. The organic matter levels have a high relationship with Fe. Likewise, this metal shows significant associations with Cd and Cu, which indicates that the generated source is the same. It is concluded that the contributions of Fe, Mg, and Mn come from the agricultural and livestock activities carried out along the "Palizada" river, where its high agricultural and livestock productivity is an essential characteristic of the municipality.

Likewise, the absence of effective programs for monitoring and controlling pollutants in the Mexican coastal environment, the growing industrialization, and urbanization have caused more than 30% of the rivers and lagoons in the Gulf of Mexico to be contaminated. The sediments represent a reservoir of heavy metals that contributes significantly to the bioavailability of aquatic organisms. On the other hand, the levels of organic matter in some sites exceed the criteria that have been established for marine areas where these levels should not be greater than 10%. These high levels of organic matter corroborate that the "Palizada" river directly influences anthropogenic discharges and rain slides.
