Contents

**Preface XI**


Chapter 2 **The Hidden Face of Nitrogen Oxides Species: From Toxic Effects to Potential Cure? 19**

Ségolène Depayras, Tatiana Kondakova, Hermann Josef Heipieper, Marc GJ Feuilloley, Nicole Orange and Cécile Duclairoir-Poc


Preface

tal compartments.

Environmental contamination is a serious problem for our society worldwide, which contin‐ uously needs new monitoring and implementation of strategies for the preservation of envi‐ ronmental quality on the best plausible mode. Although a wise terminology with no strict definition is given for emerging pollutants, they can be defined as xenobiotic, synthetic or natural. In addition, different microbial communities that are not usually monitored or regu‐ lated have the possibility to introduce, by themselves, into the different environments and,

Emerging pollutants are closely associated with multiple man-made activities such as indus‐ try, transport, food production and urbanization, which are necessary for the development of our modern society. In several cases, discharge of emerging pollutants into the environ‐ ment has likely occurred for an extensive period of time, but detection, identification and quantification may not have been performed until new strategies and methodologies for rec‐ ognition were developed. In other cases, synthesis of new chemicals or novel applications are forms of use for known contaminants, and final disposal of preexisting chemicals, not necessarily toxic, can generate new sources of emerging pollutants in multiple environmen‐

Few regulatory agencies have proposed methods for establishing provisional safety levels of emerging pollutants. According to the United Nations Educational, Scientific, and Cultural Organization (UNESCO), these xenobiotics include mainly "…compounds found in phar‐ maceuticals, personal care products, pesticides, industrial and household products, metals, surfactants, industrial additives and solvents". The US Environment Protection Agency (US EPA) states that an emerging pollutant "… is a chemical or material that is characterized by a perceived, potential, or real threat to human health or the environment or a lack of pub‐ lished health standards….". However, today there is no international consensus on the term "emerging pollutants" and it remains problematic. It is not easy to conclude which type of xenobiotic, belonging to different classes, should or should not be included in the list of these contaminants because they represent a changing reality, dependent on perspective as well as timing. Emerging pollutants are currently not included in international legislation mostly because there is not enough information on toxicity, behavior and ecotoxicological effects to establish threshold values. In general, the chemical structure of emerging pollu‐ tants comprises diverse, and origin, and they can be released from either point or diffuse pollution sources, i.e., effluents of wastewater treatment plants from urban or industrial areas and atmospheric deposition or from crop and animal activities. Despite the rate of sci‐ entific publications covering the problematic of "emerging pollutants" input into the envi‐ ronment, the frequency of occurrence, the last fate and the deleterious effects, the knowledge of the real effects of this particular type of xenobiotic remains fragmentary.

then, exert unfavorable ecological and/or human health consequences.
