Arsenic in waters, soils, sediments, and biota from Mexico: An environmental review

We reviewed over 226 studies dealing with arsenic (As) in water bodies (124 sites or regions; 5,834 samples), soils (44; 2,700), sediments (56; 765), rocks (6; 85), mine waste (25; 582), continental plants (17 (77 species); 571), continental animals (10 (32 species); 3,525) and aquatic organisms (27 (100 species) 2,417) in Mexico. In general, higher As concentrations were associatedwith specific regions in the states ofHidalgo (21 sites), San Luis Potosi (SLP) (19), Baja California Sur (15), Zacatecas (5), and Morelos (4). High As levels have been detected in drinking water in certain locations of Coahuila (up to 435 mu g L-1) and Sonora (up to 1004 mu g L-1); in continental surficial water in Puebla (up to 780 mu g L-1) andMatehuala, SLP (up to 8684 mu g L-1); in groundwater in SLP (up to 16,000 mu g L-1) and Morelia, Michoacan (up to 1506,000 mu g L-1); in soils in Matehuala, SLP (up to 27,945 mu g g(-1)) and the Xichu mining area, Guanajuato (up to 62,302 mu g g(-1)); and in sediments in Zimapan, Hidalgo (up to 11,810 mu g g(-1)) and Matehuala, SLP (up to 28,600 mu g g(-1)). In contaminated arid and semi-arid areas, the plants P. laevigata and A. farnesiana exhibit the highest As levels. These findings emphasize the human and environmental risks associated with the presence of As in such regions. A synthesis of the available techniques for the removal of As in water and the remediation technologies for As contaminated soils and sediments is given. The As occurrence, origin (geogenic, thermal, mining and anthropogenic) and evolution in specific regions is summarized. Also, the mobilization and mechanisms to explain the As variability in continental environments are concisely given. For future research, a stratified regional sampling is proposed which prioritizes critical sites for waters, soils and sediments, and biota, considering the subpopulation of foods from agriculture, livestock, and seafood. It is concluded that more detailed and comprehensive studies concerning pollution levels, as well as As trends, transfer, speciation, and toxic effects are still required. (C) 2020 Elsevier B.V. All rights reserved.