ReviewEmerging pollutants (EPs) in Latin América: A critical review of under-studied EPs, case of study -Nonylphenol-
Graphical abstract
Introduction
In the last two centuries, the use of chemicals has contributed to the economic and social development worldwide. As a result, thousands of chemical mixtures (synthetic and natural) are now present in the environment and daily life. Global production of synthetic chemicals has increased exponentially, between 1903 and 2000 the annual chemical production increased from 1 million to 400 million tons and from 2002 to 2011 > 50% of chemicals were classified as environmentally harmful and 70% with significant environmental impact. By 2017, 97.8 million tons were reported as hazardous to the environment and 91.8 million tons as hazardous to health (EUROSTAT, 2019; Gavrilescu et al., 2015; WWF, 2020). There are >80,000 chemicals that are used in manufacturing products to meet human needs such as, cleaning products, drugs (prescription and over the counter), cosmetics, fragrances, personal care products, among others. These products are used and disposed of globally in the environment after a manufacturing process as industrial waste directly impacting on water quality (Naidu et al., 2016).
In general, water quality research focuses on nutrients, microbial contaminants, heavy metals and priority pollutants. Recently, there has been acknowledged a new type of pollutants (“emerging pollutants”) that affect significantly the quality of water and causes potential public health and security problems (Bilal et al., 2019). However, due to its recent detection and low concentrations (μg L−1, ng L−1), there is a gap in knowledge about its occurrence, fate, behavior, risk assessment, and ecological and human effects. These compounds includes daily use products like surfactants, flame retardants, pharmaceuticals, personal care products, biocides, gasoline additives, polar pesticides and their degradation products. The main source of EPs are municipal wastewaters (Deblonde et al., 2011) and conventional water treatment plants that are not designed to remove this kind of pollutants and their degradation resistant metabolites, so they are disposed of directly into water bodies (Van Zijl et al., 2017). The investigation of the composition of EPs and their removal during wastewater treatment is scarce, due to the lack of monitoring programs because of the non-existing specific regulations (Rasheed et al., 2019). The occurrence of EPs in wastewater, its behavior during treatment and the production of drinking water are then key areas that require immediate studies.
Section snippets
Emerging pollutants and its importance in human and environmental health
EPs emissions have become an environmental global issue because of the limited regulations and worldwide consensus that establish legislations in this regard. The Environmental Protection Agency (EPA) defines the EPs as chemical compounds without regulations where its behavior, environmental and public health impacts are poorly understood (EPA, 2017). Some of these compounds present endocrine disruption activity and they have been defined as exogenic agents that interfere with the synthesis,
Regulatory frameworks for emerging contaminants and the problem of implementation
Outstanding in continuous monitoring measures and regulation of maximum permissible limits in environmental matrices are the United States and the European Union through their environmental regulatory agencies (Table 1). For example, the EPA created the Drinking Water Contaminant Candidate List which includes some drugs like carbamazepine, naproxen, sulfamethoxazole, ibuprofen, gemfibrozil, atenolol, diclofenac, erythromycin, and bezafibrate (EPA, 2018).
For the EU, it introduced a list of
Emerging pollutants in Latin America
Research on EPs in Latin America is recent even though their concentration levels have increased significantly in the past 10 years (Bedoya-Ríos et al., 2018; Botero-Coy et al., 2018; Hernández et al., 2015). In 1999, one of the first studies was published in this regard, where they reported to found drugs and its metabolites in water bodies from Rio de Janeiro and discussed the lack of information of EPs in Latin America (Stumpf et al., 1999).
The studies aimed at monitoring in different water
Case study of under-studied emerging pollutants in Latin America: nonylphenol
Nonylphenol ethoxylated (NPE) is a non-ionic surfactant usually employed as a surfactant in domestic and industrial detergent formulations (Quiroga et al., 2019; Vazquez-Duhalt et al., 2005). The use of NPE in detergents represents 80% of its demand because of the low cost and the great detergent capacity (Araujo et al., 2018). Another uses include herbicides, pesticides and in production of paper, textiles, plastics, rubbers and paints (Ferrara et al., 2011; Perron and Juneau, 2011). The high
Regulation for the use of nonylphenol and their ethoxylates
Strategies and regulations have been developed to urgently deal with EDCs, among them NP (Table 2). For example: (i) The EU restricted its use with the Directive 2003/53/EC which establishes that it must not be commercialized or used as a substance in mixtures in quantities equal or higher than 0.1% in mass of NP or 1% in mass of NPE (Union, 2003). Moreover, the Directive 775/2004 (02/2076) prohibited its use for the elaboration of pesticides (Union, 2006), (ii) The Water Framework Directive of
Environmental levels of NP in the water of Latin America compared to other regions
Even though the presence of EPs like the NP is known worldwide there is a gap of knowledge about its distribution in some geographic areas like Latin America (Llorca et al., 2017). A compilation of studies of NP concentrations in different water bodies worldwide is shown in Table 3. Even though there are similitudes between concentrations of NP found in different regions, it is important to acknowledge that the matrixes are different. For example, while in Mexico there are concentrations of NP
Technological development for substitution of NPE in detergents
NPE is substituted usually by ethoxylated alcohols; less effective surfactants but safer for the environment because of its fast biodegradation. However, some studies suggest that biodegradation byproducts have low solubility and are absorbed in residual sludges (Soares et al., 2008). On the other hand, natural surfactants may also substitute alkylphenol ethoxylates; for example, alkyl polyglucosides (APGs) are nonionic surfactants produced by removable raw materials like corn, potatoes, wheat
Conclusions
Emerging pollutants present a new global challenge about water quality with potentially important threats to human health and ecosystems. The importance of this issue is such that the United Nations included it in the Objectives of Sustainable Development as Goal No. 6 (Ensure access to water and sanitation for all). There is a lack of information about EPs occurrence in some regions of the world, significantly in developing countries such as the Latin American countries. This review identified
Declaration of competing interest
The authors declare that they have no known competing financial interest or personal relationships the could have appeared to influence the work reported in this paper.
Acknowledgements
The authors acknowledge grants and fellowships from the National Council on Science and Technology-Sectoral Research Fund for Education Basic-Science # A1-S-28176 and FAI-UASLP-23749-2019.
References (116)
- et al.
Nonylphenol and octylphenol in human breast milk
Environ. Int.
(2008) - et al.
Modeling the exposure of wild fish to endocrine active chemicals: potential linkages of total estrogenicity to field-observed intersex
Water Res.
(2018) - et al.
Emergent contaminants: endocrine disruptors and their laccase-assisted degradation – a review
Sci. Total Environ.
(2018) - et al.
Emerging contaminants of high concern and their enzyme-assisted biodegradation – a review
Environ. Int.
(2019) - et al.
Determination of 4-nonylphenol and 4-tert-octylphenol compounds in various types of wastewater and their removal rates in different treatment processes in nine wastewater treatment plants of Iran
Chin. J. Chem. Eng.
(2018) - et al.
A review of the effects of emerging contaminants in wastewater and options for their removal
Desalination
(2009) - et al.
An investigation into the occurrence and removal of pharmaceuticals in Colombian wastewater
Sci. Total Environ.
(2018) - et al.
The SOLUTIONS project: challenges and responses for present and future emerging pollutants in land and water resources management
Sci. Total Environ.
(2015) - et al.
Occurrence, fate and toxic effects of the industrial endocrine disrupter, nonylphenol, on plants - a review
Ecotoxicol. Environ. Saf.
(2019) Histological and ultrastructural alterations of the Italian newt (Lissotriton italicus) skin after exposure to ecologically relevant concentrations of nonylphenol ethoxylates
Environ. Toxicol. Pharmacol.
(2018)