Spatial and temporal trace metal distribution of a Peruvian basin: recognizing trace metal sources and assessing the potential risk

Abstract

Recent efforts have been made to determine the environmental impact of mining over the past 11 years in the Jequetepeque River basin, in northern Peru. We have now analyzed data from two studies to elucidate the spatial and temporal trace metal distributions and to assess the sources of contamination. These two studies were carried out from 2003 to 2008 by a Peruvian government administration and from 2008 to 2010 by us. We analyzed 249 samples by principal component analysis, measuring: pH, electrical conductivity, total dissolved solids, total suspended solids, chloride, weak-acid-dissociable cyanide, total cyanide, nitrite and nitrate, ammonium, sulfate, and trace metals and metalloids (Al, As, Ca, Cd, Cu, Cr, Fe, Mg, Mn, Ni, Pb, and Zn). Within the spatial distribution of the basin, the highest Al, As, Cu, Fe, Ni, and Pb concentrations were found at the closest point to the mine sites for both periods of time, with the higher peaks measured during the first years of the sampling data. Temporal trends showed higher concentrations of Cu and Fe in samples taken before 2005, at which point the two mines were closed. Risk assessment was quantified by the hazard quotient as related to water ingestion. The risk for human health posed by the concentrations of several trace metals and metalloids was found to be highly adverse (As and Cr), significant (Al, Cd, Cu, Fe, and Pb), or minimal (Ni and Zn).

Experimental Study of Mobility and Kinetic Characterization of Trace Elements in Contaminated Sediments from a River Basin in Northern Peru

“…The amount of trace elements released is quite significant as was discussed previously (Figure 4) and it is related with the higher mobility index obtained for sediments M3 and M4. This fact can be correlated with the results reported by Yacoub et al (2013) in which high concentrations of the trace elements were detected and measured in water samples from 2003 to 2010 in several sampling campaigns at the Jequetepeque basin. Concentrations of Cd, Pb, As, and Cu in water were estimated (following the hazard quotient methodology) to be of significant risk to human health and also to the environment at the river basin .…”

“…It was evaluated using classical chemical monitoring methods for trace-level pollutants present in water and sediment (Yacoub et al 2012;Yacoub et al 2013;Yacoub et al 2014). From these findings, the present study seeks to deepen the knowledge about the most polluted sites in environmental terms by an accurate estimation of metal bioavailability and potential risk.…”

Virtual water trade and the contestation of hydrosocial territories

“…Peasant communities have been protesting for a decade. Mining expansion into the Quilish mountains and opening of the new Conga mine are contested by inhabitants of the hydrosocial territory, as those mines will affect negatively their water quality and quantity (Yacoub, Blazquez, Pérez-Foguet, & Miralles, 2013). In 2010 the army was sent to Cajamarca to repress massive protest rallies violently.…”

Territorios hidrosociales y minería en Cajamarca. Perú

“…Ubicación de los monitoreos realizados en la cuenca del Jequetepeque en el Perú Elaboración propia. Basada en Yacoub, 2013. nes se entretejen con consideraciones biofísicas de la geología, geomorfología, hidrología y ecología de las zonas para delimitar el espacio y la cantidad de muestras a estudiar. Hemos observado cómo -de manera recurrente-se discuten las características del monitoreo descritas, excluyendo precisamente del análisis ciertas substancias presumiblemente asociadas a la empresa minera.…”

“…Existen algunas limitaciones en el caso de la DESA, que en cierto momento obtuvo quejas por parte de la población local de diversos sectores campesinos, en-26 Para más detalles ver Yacoub, Blázquez, Pérez-Foguet y Miralles, 2013;Yacoub, Pérez-Foguet, Miralles y Valderrama, 2014. 27 Stratus Inc., 2003CAO, 2007;DESA, 2008;Yacoub, Blazquez, Pérez-Foguet y Miralles, 2013;Yacoub, Pérez-Foguet, Miralles y Valderrama, 2014. tes gubernamentales o personal de la universidad.…”