Waste into rivers: a residual issue? The case of the UNESCO’s site of the Quebrada De Humahuaca, NW Argentina

The Quebrada de Humahuaca in North West Argentina is a world heritage site listed by the UNESCO since 2003. As pollution is increasing dramatically, a pluridisciplinary, annual-long survey was conducted along the valley to determine dominant patterns in waste management and water quality. Along with the habit of discarding waste into the river, urbanizations have been identified as having a deep influence on the river water quality: iron together with maximum peaks of nitrite and nitrate are related with the anthropogenic activity at Humahuaca, whereas the concentrations of arsenic increase from north to south, with maximum peaks of up to 13.50 and 14.50 μg L −1 measured during the rainy season at Maimará and Volcán, respectively. In this underdeveloped region, economic struggles and waste management customs revealed as major factors causing the environmental degradation. The inclusion in the UNESCO’s sites list was insufficient in preserving this world heritage site. The approach discussed in this article suggests a straightforward analytical measurement of the river hydrochemical properties during the rainy season in arid/semi-arid regions with monsoonal regime, to assess the effects of waste dumping along watercourses. In addition to scientific evaluations, both public acceptance and the establishment of proper waste management infrastructure are fundamental to ensuring the preservation of human and environmental health.