This publication provides guidance to water-sector decision makers and planners on how to deal with the quality dimension of groundwater resources management in the World Bank's client countries. There is growing evidence of increasing pollution threats to groundwater and some well-documented cases of irreversible damage to important aquifers. This guide has been produced in the belief that groundwater pollution hazard assessment must become an essential part of environmental best practice for water supply utilities. The guide is particularly relevant for the World Bank's Latin American and Caribbean Region, where many countries have initiated major changes to modernize their institutional and legal framework for water resources management, but may not yet have considered groundwater at the same level as surface water, because of lack of awareness and knowledge of groundwater issues and policy options.

The objective of this study was to evaluate the quality of surface water used for irrigation in the Huallaga basin. We worked with water quality monitoring data in the basin conducted by the National Water Authority (ANA) counting 139 monitoring points, evaluating 41 parameters for the period 2014 - 2019, the Peruvian Water Quality Index (ICA - PE) intended for irrigation was calculated, using as reference values the Environmental Quality Standard (ECA) for surface water in category 3 D1 (irrigation water). Of the 139 monitoring points, 26 (18.71%) were of excellent quality, 62 (44.60%) of good quality, 35 (25.18%) of fair quality, 13 (9.35%) of poor quality and 3 (2.16%) of very poor quality. The main contaminants found were thermotolerant coliforms, Escherichia coli, which on average exceeded the ECA by 606 and 288 times and by 53.4% (1029/1927) and 38.9% (701/1803) respectively. Contamination by organochlorine pesticides, in 100% (10/10) of the chlordane measurements the RCT was exceeded and with respect to Endrin, Aldrin and DDT the RCT was exceeded in 40% (10/25). The pH, in 25.6% of the measurements the water was outside the ranges tending to alkalinity and for manganese, iron and aluminum, exceeded the ECAs in 17.7%, 13.3% and 11.2% respectively. The main contaminant sources are agricultural and municipal wastewater and the presence of critical points of solid waste. | El objetivo de este estudio fue evaluar la calidad del agua superficial destinada para riego en la cuenca Huallaga. Se trabajaron con los datos de monitoreo de calidad del agua en la cuenca realizados por la Autoridad Nacional del Agua (ANA) contando con 139 puntos de monitoreo, evaluando 41 parámetros para el periodo 2014 – 2019, se calculó el Índice de Calidad de Agua peruano (ICA – PE) destinado para riego, usando como valores de referencias al Estándar de Calidad Ambiental (ECA) para aguas superficiales en la categoría 3 D1 (aguas de regadío). De los 139 puntos de monitoreo, 26 (18,71%) de ellos resultaron con una calidad excelente, 62 (44,60%) con calidad buena, 35 (25,18%) con calidad regular, 13 (9,35%) con calidad mala y 3 (2,16%) con pésima calidad. Los principales contaminantes encontrados fueron los Coliformes Termotolerantes, Escherichia coli, que en promedio sobrepasaron el ECA en 606 y 288 veces y en el 53,4% (1029/1927) y 38,9% (701/1803) respectivamente. La contaminación por pesticidas organoclorados, en el 100% (10/10) de las mediciones del clordano se sobrepasó el ECA y con respecto al Endrín, Aldrín y DDT se sobrepasó el ECA en el 40% (10/25). El pH, en el 25,6% de las mediciones el agua se encontró fuera de los rangos tendiendo a la alcalinidad y para el manganeso, hierro y aluminio, sobrepasaron los ECAs en 17,7%, 13,3% y 11,2% respectivamente. Las principales fuentes contaminantes son las aguas residuales agrícolas y municipales, así como también la presencia de puntos críticos de residuos sólidos.

This study examines how environmental issues have been addressed in the water sector in Brazil, within the context of activities of the Federal Government, generally, and those implemented under Bank sector operations, in particular. The core focus of the study lies in the management of water quality, as it affects both the users of raw water, and those who are primarily concerned with the disposal of wastewater. The report considers the following three sectoral areas concomitantly - water resources management, water supply and sanitation, and, the environment - thus limiting its review, and focus to those themes which are key to the over-arching issue of water quality. Water resources management in the country relied upon heavy investments in medium, and large scale projects that provided basic infrastructure for water uses. However, these have produced questionable impacts in terms of reducing poverty, and inequality. One of the reasons for this, has been the poor infrastructure management, which despite its importance, has been largely underestimated. While improvements in the utilization of existing infrastructure in the water sector remain critical, it needs to be complemented by incentives to both service providers, and water users. Moreover, low economic, environmental, and social returns from investments in the water sector, reflect the tendency to distract attention from the objectives in the design, and implementation of projects. Thus, an assessment of water quality goals is required, which should be based on systematic evaluations of the costs, and benefits of reaching alternative standards, and explicit social objectives.