Metal Discharges by Sinaloa Rivers to the Coastal Zone of NW Mexico

Abstract

The aim of this work was to survey the discharges of dissolved and particulate Cd, Cu, Fe, Mn, Pb and Zn of the eight main rivers of Sinaloa State to the Mexican coastal environment. Zn was the most abundant dissolved metal and Fe was the most abundant particulate (8.02-16.90 and 51.8-1,140.3 μg/L, respectively). Only particulate Mn had significantly (p = 0.028) higher values in summer-fall (rainy season), whereas the significantly (p = 0.036) higher values of dissolved Zn were observed in winter and spring. The highest annual total discharges to Sinaloa coastal waters were those of the rivers San Lorenzo and Piaxtla (>2 × 10(3) m.t.) and the lowest those of rivers Baluarte and El Fuerte (349 and 119 m.t., respectively). Pb concentrations may become of concern, because they are higher than the value recommended for the welfare of aquatic communities of natural waters.

Humoral and Haemocytic Responses ofLitopenaeus vannameito Cd Exposure

“…The coastal environments of the Mexican Pacific receive metal contaminants from multiple sources, such as the several rivers flowing from important mining districts [1] and the waterways and canals draining the fertile coastal plains of the states of Sonora and Sinaloa, which support highly intensive agricultural activities [2, 3]. Because of this, the metal contents of the marine biota are under continuous scrutiny [4, 5], and among these the levels of cadmium detected in different aquatic organisms of the coastal environments of NW Mexico indicate that this metal might become of concern for aquatic life and possibly for human health [6].…”

Heavy Metals in Waters and Suspended Sediments Affected by a Mine Tailing Spill in the Upper San Lorenzo River, Northwestern México

“…In waters from the San Pedro River (Cananea mining district), which is affected by drainage from mine tailings, extremely variable levels were found (Gomez-Á lvarez et al 2009): 10-63,950 for Cd, 60-1,200,000 for Cu, \2-75,000 for Pb, and 10-54,000 lg L -1 for Zn. Frías-Espericueta et al (2014) examined eight rivers in the downstream portion of Sinaloa state (including the San Lorenzo River), in which the levels of the dissolved fraction were higher for Cd (0.32-1.06 lg L -1 ) and Pb (3.43-8.27 lg L -1 ) and lower for Cu (1.36-2.10 lg L -1 ) and Zn (8.0-16.9 lg L -1 ) than the levels found in this study. This rough comparison reveals that dissolved Cu and Zn are enriched in the waters of the El Comedero dam, upstream of the San Lorenzo River and in the Los Remedios River.…”

“…Sampling sites are from Fig. 1; SLD corresponds to a site in the San Lorenzo River 60 km downstream of El Comedero dam that was analyzed by Frías-Espericueta et al (2014). An asterisk indicates a concentration that exceeds the PEL for sediments (CCME 2001) or the WHO for water (UNEP 2008) Bull Environ Contam Toxicol upper waters.…”

“…2, bottom row). The concentrations of suspended Cd, Cu, Pb and Zn were higher in comparison to those from downstream waters of the San Lorenzo River (SLD) (Frías-Espericueta et al 2014). As, Ag and Hg data were not available for SLD.…”

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“…The state of Sinaloa releases only close to 2.2% of these discharges (9.8 x 10 3 kg y -1 ), but its coastal waters are likely to receive Hg 2+ fro m other sources, since they are the recipients of several rivers and streams which originate fro m the metal-rich Sierra Madre Occidental (Frías-Espericueta et al, 2014). In particular, the orig ins of the rivers reaching the central and southern part of the State (San Lorenzo, Elota, Piaxt la, Presidio and Baluarte) lie close or within the gold-producing mining regions 3, 5, 6 and 7 of the neighboring state of Durango (SGM, 2014).…”