Groundwater from the Mocorito River coastal aquifer (MORCA), located in the agricultural valley of Culiacan, Mexico, has been historically employed for both human consumption and irrigation of its overlaying agriculture fields. In order to assess the levels and distribution of As, Cd, Cr and Pb in MORCA, as well as, to determine their sources and to estimate their potential health risks, groundwater samples were collected from wells at eighteen sites during the dry and rainy seasons. In the dry season mean dissolved concentrations (μg L-1) of As, Pb, Cd and Cr were 3.19, 0.05, 0.02 and 0.15, respectively, and their total (unfiltered) concentrations were 4.10, 0.47, 0.05 and 0.52, respectively. While in the rainy season, their dissolved concentrations were 4.60, 0.03, 0.01 and 0.06, respectively and their total concentrations were 5.58, 0.25, 0.01 and 0.12, respectively. On average, concentrations of these four Potentially Toxic Elements (PTEs) were below national and international guidelines for drinking water. Concentrations of As exceeded the safe value proposed for the World Health Organization (10 μg L-1), at three sites and yielded relatively high values of both Chronic Daily Intake and Hazard Quotient. Lifetime Cancer Risk for As indicated the probability for developing this disease of 1 in 10, 000 inhabitants. Pearson’s correlation and principal component analysis (PCA-Varimax) were carried out. According to these, all the PTEs concentrations were mainly derived from natural lithogenic sources. Arsenic concentrations constitute potential human health concerns for both direct consumption and its bioaccumulation in local crops. Finally, due to high As concentrations in some sites in the aquifer, the implementation of a sustainable groundwater management plan in the MORCA, that include a monitoring of PTE levels, is recommended.