This document is intended to provide an overview of the major components of surface and ground water quality and how these relate to ecosystem and human health. Local, regional and global assessments of water quality monitoring data are used to illustrate key features of aquatic environments, and to demonstrate how human activities on the landscape can influence water quality in both positive and negative ways. Clear and concise background knowledge on water quality can serve to support other water assessments.

The book attempts to covers the main fields of water quality issues presenting case studies in various countries concerning the physicochemical characteristics of surface and groundwaters and possible pollution sources as well as methods and tools for the evaluation of water quality status. This book is divided into two sections: Statistical Analysis of Water Quality Data;Water Quality Monitoring Studies.

The quality of drinking water is paramount for public health. Despite important improvements in the last decades, access to safe drinking water is not universal. The World Health Organization estimates that almost 10% of the population in the world do not have access to improved drinking water sources. Among other diseases, waterborne infections cause diarrhea, which kills nearly one million people every year, mostly children under 5 years of age. On the other hand, chemical pollution is a concern in high-income countries and an increasing problem in low- and middle-income countries. Exposure to chemicals in drinking water may lead to a range of chronic non-communicable diseases (e.g., cancer, cardiovascular disease), adverse reproductive outcomes, and effects on children’s health (e.g., neurodevelopment), among other health effects. Although drinking water quality is regulated and monitored in many countries, increasing knowledge leads to the need for reviewing standards and guidelines on a nearly permanent basis, both for regulated and newly identified contaminants. Drinking water standards are mostly based on animal toxicity data, and more robust epidemiologic studies with accurate exposure assessment are needed. The current risk assessment paradigm dealing mostly with one-by-one chemicals dismisses the potential synergisms or interactions from exposures to mixtures of contaminants, particularly at the low-exposure range. Thus, evidence is needed on exposure and health effects of mixtures of contaminants in drinking water. Finally, water stress and water quality problems are expected to increase in the coming years due to climate change and increasing water demand by population growth, and new evidence is needed to design appropriate adaptation policies. This Special Issue of International Journal of Environmental Research and Public Health (IJERPH) focuses on the current state of knowledge on the links between drinking water quality and human health.

This book covers water quality indices (WQI) in depth – it describes what purpose they serve, how they are generated, what are their strengths and weaknesses, and how to make the best use of them. It is a concise and unique guide to WQIs for chemists, chemical/environmental engineers and government officials. Whereas it is easy to express the quantity of water, it is very difficult to express its quality because a large number of variables determine the water quality. WQIs seek to resolve the difficulty by translating a set of a large number of variables to a one-digit or a two-digit numeral. They are essential in communicating the status of different water resources in terms of water quality and the impact of various factors on it to policy makers, service personnel, and the lay public. Further they are exceedingly useful in the monitoring and management of water quality. With the importance of water and water quality increasing exponentially, the importance of this topic is also set to increase enormously because only with the use of indices is it possible to assess, express, communicate, and monitor the overall quality of any water source. - Provides a concise guide to WQIs: their purpose and generation - Compares existing methods and WQIs and outlines strengths and weaknesses - Makes recommendations on how the indices should be used and under what circumstances they apply

This guidebook, now thoroughly updated and revised in its second edition, gives comprehensive advice on the designing and setting up of monitoring programmes for the purpose of providing valid data for water quality assessments in all types of freshwater bodies. It is clearly and concisely written in order to provide the essential information for all agencies and individuals responsible for the water quality.