Preface

Emerging contaminants are synthetic or natural compounds and microorganisms produced and used by humans that tend to have adverse ecological and human health effects once they reach the environment. These contaminants are present in everyday life in personal care products, pharmaceuticals, detergents, surfactants, pesticides, and so on. Up until the 1990s, most of these contaminants were not identified by environmental monitoring programs because their production and use were not intended to have harmful consequences for the environment and living organisms. However, not only are these contaminants themselves problematic but so are their metabolic/degradation products. Today, there are many emerging contaminants, including domestic and industrial chemicals, hospital medicaments, and farming chemicals. All these compounds are persistent in the environment (water, soil, sediments), can spread far and wide, can bioaccumulate easily, and are toxic. This book, *Emerging Contaminants*, discusses a wide variety of toxins that have adverse effects on our lives.

The first section provides detailed information about the classification, sources, adverse effects, and toxicology of emerging contaminants as well as some of the most used analytical techniques for their quantification. People use many substances at home, in hospitals, and in agricultural and industrial processes. On one hand, these substances are necessary for our wellbeing, but on the other hand, they can damage the environment, organisms, and human health. Many of these substances end up in the environment through wastewater, farming activities, industrial wastes, water treatment processes, and so on. The classification of emerging contaminants is based on their use (such as pesticides, antibiotics, etc.). The chapters in the first section give a clear picture of the main classes of these pollutants as well as additional information concerning their origin in the environment and the problems that they cause. These contaminants are found in low levels (trace to ultra-trace) in the environment, in the ppt–ppm range. Even at these levels, emerging contaminants can have toxic effects. For the analyst, identifying contaminants at ultra-trace concentrations is a challenge, therefore special attention is paid in this section to analytical techniques for sample treatment and quantification, especially in water and biota samples.

One of the most important groups of emerging contaminants is pesticides. As such, the second section of this book presents some recent work on pesticides. Many chemical formulations are used for many years in agriculture as insecticides, fungicides, herbicides, rodenticides, and so on. The use of pesticides in agriculture is necessary, but it must be done carefully and in a controlled way because their use can cause soil pollution, food contamination, and broader environmental pollution that affects water ecosystems. Many pesticide formulations, due to their adverse environmental and health effects, have been banned, such as some organochlorine pesticides like DDT, aldrin, heptachlor, chlordane, etc.). Despite being banned, these compounds and their metabolites persist in the environment. Nowadays, pesticides continue to be in use in agriculture in many other formulations, mostly with N, S, and P; therefore chemical, biological, and toxicological monitoring should always be at the center of attention for institutions and scientists.

The third section of the book is dedicated to the impact of pharmaceutical active compounds (PhACs) in the environment. More than 3000 chemical substances are used as medicines for humans and animals. Human and veterinary drugs (antibiotics, antiseptics, antihistamines, endocrine disruptors, and many other classes) are vital, but their use can be problematic for the environment and living things. Hospital wastewaters are the main sources of pharmaceuticals in the environment. These molecules can promote drug tolerance or resistance to target organisms (e.g., antibiotic resistance in bacteria, or analgesic tolerance in humans) and unwanted effects in non-target organisms (e.g., alteration of sex ratio and decreased fertility) even in low concentrations. Their levels in hospital wastewaters and the environment are reported from ngL-1 to ugL-1. Besides their parent molecules, PhACs are often excreted as metabolites that can be even more toxic than native molecules.

The fourth section of the book presents information on some other classes of emerging contaminants such as polybrominated biphenyl ethers, microplastics, industrial base contaminants, and others. Due to their persistence, these contaminants persist in the environment for a long time after their use. In addition, because of their chemical structures they can accumulate easily in organisms and thus cause various problems not only to those organisms but also to the food chain because of the biomagnification process.

*Emerging Contaminants* is an informative book for researchers in the field and we hope it will direct more attention to the numerous toxic compounds that we confront in our everyday lives.

## **Aurel Nuro** Department of Chemistry, Faculty of Natural Sciences, Tirana University, Tirana, Albania

**1**

Section 1

What are Emerging

Contaminants?

Section 1
