EVALUATION OF WATER QUALITY IN CAJAMARCA, PERU Annual Monitoring Report 2004­2005 Prepared for: Compliance Advisor/Ombudsman (CAO) 2121 Pennsylvania Ave., NW Washington, DC 20433, USA and: La Mesa de Diálogo y Consenso CAO­Cajamarca Jr. Los Cerezos 127, Urbanizacion El Ingenio Cajamarca, Perú Project Team: David Atkins, Project Manager Carlo Calderon Eduardo Montoya Elizabeth Morales December 2005 Evaluation of the Quality of Water in Cajamarca, Peru Annual Monitoring Report, 2004­2005 Table of Contents 1. Introduction .....................................................................................................1 1.1 Investigation Overview......................................................................................3 1.2 Project Organization ..........................................................................................4 1.3 Report Organization...........................................................................................4 2. Study Overview................................................................................................5 2.1 Geographic Overview ........................................................................................5 2.2 Community Water Use ......................................................................................6 2.3 Mine Water Use.................................................................................................6 2.4 Participatory Monitoring Program Design..........................................................8 2.5 Sample Locations and Laboratory Design ..........................................................8 3. Data Quality Assessment ...............................................................................11 3.1 General Considerations....................................................................................11 3.2 Methods...........................................................................................................11 3.3 Laboratory Procedures.....................................................................................13 3.4 Analytical Data Validation...............................................................................14 3.5 Quality Assurance Samples (QA/QC) .............................................................14 3.5.1 Institution Data ................................................................................................14 3.5.2 Mesa Samples..................................................................................................15 3.5.2.1 Blank Samples.................................................................................................15 3.5.2.2 Duplicate Samples ...........................................................................................15 3.5.2.3 Standard Reference Samples............................................................................16 3.6 Conclusions ....................................................................................................16 4. Water Quality Assessment.............................................................................18 4.1 Baseline Water Quality ....................................................................................18 4.2 Water Quality Assessment Methods.................................................................19 4.2.1 General Water Law of Peru Standards..............................................................21 4.2.2 International Water Quality Guidelines for Different Uses ...............................22 4.2.2.1 Livestock Guidelines .......................................................................................22 4.2.2.2 Irrigation Guidelines ........................................................................................23 4.2.2.3 Human Consumption Guidelines......................................................................23 4.3 Water Quality Assessment Results...................................................................24 4.3.1 Porcon Basin ..................................................................................................25 4.3.1.1 Human Consumption Water Quality ................................................................25 4.3.1.2 Canal Water Quality ........................................................................................27 4.3.1.3 Critical Point Water Quality.............................................................................27 4.3.1.4 4.3.2 Rejo Basin.......................................................................................................28 4.3.2.1 Canal Water Quality ........................................................................................29 4.3.2.2 Critical Point Water Quality.............................................................................29 4.3.3 Honda Basin ...................................................................................................29 4.3.3.1 Canal Water Quality ........................................................................................30 4.3.3.2 Critical Point Water Quality.............................................................................30 4.3.4 Chonta Basin ..................................................................................................31 4.3.4.1 Canal Water Quality ........................................................................................31 4.3.4.2 Critical Point Water Quality.............................................................................32 4.3.5 Mine Monitoring Points..................................................................................33 5. Summary, Conclusions and Recommendations............................................34 5.1 Data Quality Assessment Summary .................................................................36 5.1.1 Mesa Duplicate Samples Compared to Institution Samples ..............................36 5.1.2 Quality Control Samples..................................................................................37 5.2 Water Quality Assessment Summary ...............................................................37 5.2.1 Porcon Basin ..................................................................................................37 5.2.1.1 Water Quality for Human Consumption...........................................................38 5.2.1.2 Water Quality for Agriculture ..........................................................................38 5.2.1.3 Water Quality in Critical Points .......................................................................38 5.2.2 Rejo Basin.......................................................................................................38 5.2.2.1 Water Quality in Critical Points .......................................................................39 5.2.3 Honda Basin ...................................................................................................39 5.2.3.1 Water Quality in Critical Points .......................................................................39 5.2.4 Chonta Basin ..................................................................................................39 5.2.4.1 Water Quality in Critical Points .......................................................................40 5.2.5 Mine Monitoring Points..................................................................................40 5.3 Conclusions .....................................................................................................40 5.4 Recommendations............................................................................................42 ANNEXES A. Sample Locations B. Water Quality Data Tables C. Statistical Summaries D. Water Quality Parameter Graphs E. Sampling Plan F. 2003 Mesa Water Study Summary and Recommendations G. Sampling Site Maps and Photos Evaluation of the Quality of Water in Cajamarca, Peru Annual Monitoring Report, 2004­2005 1. Introduction This report describes the objectives, methods, results, and conclusions of a participatory monitoring program to evaluate water quality in the vicinity of the Yanacocha Mining District. The Yanacocha Mining District is located in the Andes Mountains of northern Peru, approximately 15 km north of the city of Cajamarca. The mine is located on the Continental Divide at an elevation of approximately 4,000 m, and spans four basins, the Porcon, Rejo, Honda (Llaucano) and Chonta basin. The mine is operated by Minera Yanacocha S.R.L. (hereafter referred to as Minera Yanacocha). Minera Yanacocha is a joint venture of Newmont Peru Limited (51%), Compañía de Minas Buenaventura (44%), and the International Finance Corporation, the private sector lending arm of the World Bank, or IFC (5%). The monitoring program is being conducted on behalf of the Mesa de Diálogo y Consenso CAO­Cajamarca (the Mesa). The Mesa is a voluntary group of stakeholders with an interest in the economic, social, and environmental consequences of the operation of Minera Yanacocha S.R.L. (MYSRL). The Mesa includes participants from rural and urban communities, public and private institutions, and MYSRL, and was convened in September 2001 by the Compliance Advisor Ombudsman (CAO), the independent accountability mechanism of the private sector institutions of the World Bank, in response to two complaints filed on behalf of citizens in the Cajamarca area alleging adverse impacts caused by mining activities. The purpose of the Mesa is to use dialogue, conflict resolution, and consensus building approaches to promote communication,