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This book provides an overview of the current state of knowledge about the main groups of contaminants of emerging concern (CECs) in the marine environment. The relevance of these pollutants and the interest they have aroused is manifested in the large number of studies published in the last two decades, covering different aspects, from their presence and distribution the marine environment, to their fate and ecological effects. The research conducted so far has allowed to establish the main challenges and future research needs, to advance in the environmental management of CECs and to preserve and protect more effectively the marine environment, with the aim of achieving its sustainable use. The advances made in the scientific knowledge about CECs resulted primarily from the emergence of robust and sensitive instrumentation and analytical methodologies, which have made it possible to identify and quantify this type of substances at low concentrations and in complex environmental matrices, increasing our understanding of the presence of CECs in the marine environment. Regarding their impact on marine ecosystems, one of the most relevant challenges is the need to obtain information on the long-term ecotoxicological effects of CECs and their transformation products, on the toxicity of their mixtures and on the interactions between CECs and other environmental stressors. It is also necessary to develop environmental quality criteria for marine matrices, considering the most suitable sentinel species for each group of CECs. Finally, it is urgent to investigate human exposure to CECs through the consumption of seafood and through other marine and nonmarine pathways.

Current-use pesticides (CUPs) are widely used, not only in agriculture but also for human health protection and other applications. Consequently, insecticides, herbicides, and fungicides enter the marine environment and have been found in seawater, marine sediment, and biota all over the world, but in general, at relatively low concentrations, particularly at certain distances from the main pollution sources. Depending on the environmental conditions and the properties and uses of the pesticides, different seasonal or spatial distribution patterns have been observed. Bioaccumulation of CUPs has also been evidenced in certain species, including in the Artic area; however, additional data are required using adequate sentinels for each of the CUPs groups. Regarding their risk to the environment, although there is considerable information on the biological effects of CUPs obtained from acute toxicity tests, which have shown different impacts depending on the studied biological group (primary producers, invertebrates, or fishes), more data are required, particularly for chronic exposure tests and new CUPs for which application has recently started.

Microplastics (MPs), highly heterogeneous in composition, pollute all marine compartments. Also, nanoplastics (NPs) may be present in oceans; however, the absence of adequate analytical techniques makes difficult their actual assessment of complex environmental matrices. The role of plastics as a pollution vector is relevant in the marine environment since they may transfer sorbed contaminants from one compartment to another and also favor bioaccumulation of some contaminants of emerging concern (CECs) in marine organisms. The sorption of CECs on plastics from the surrounding media increases the concentration of the environmental contaminants, acting as passive samplers and favoring the transport of certain contaminants in the marine environment. This chapter will review the most current information on the sources, distribution, analytical procedures, bioaccumulation, and biological effects of MPs and NPs and their potential role as a pollution vector for CECs in the marine environment.

Microplastics are gaining worldwide attention due to their omnipresence. The marine environment is one of the most affected systems; especially the sediment compartment. Microplastic separation from the sediment matrix is the first step to evaluate its abundance and availability. Nevertheless, a lack of consistency in extraction protocols is a fact. This paper describes the optimization of the microplastic extraction procedure from marine sediments. The Plackett-Burman saturated factorial design was used to identify the significant factors and to select optimum working conditions. With this purpose, the following variables were studied: the number of extractions; the amount of sediment; the settling time; the density separation solution volume; the agitation tim and the suitability of using wet or freeze-dried sediment. The Plackett-Burman design has revealed that the mos statistically significant variables were sediment mass and agitation time. The optimized method was applied for two marine sediments collected in the Mar Menor Lagoon.

The seasonal bioaccumulation of trace metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorinated pesticides (OCPs) in sea snail (Hexaplex trunculus) and sea cucumber (Holothuria polii) from Mar Menor lagoon were characterised. The highest concentrations of p,p'-DDE were detected in the central and south part of Mar Menor lagoon. However, the highest concentrations of metals in sea snail and holothurians were detected in the influence area of El Beal wadi. Biomagnification factors (BMF) in sea snail from cockle (sea snail-cockle concentration ratio) were higher than 5 for metal and organochlorinated compounds. However, similar concentrations were observed in both species for PAHs due to gastropods capability of metabolising these pollutants. Consequently, sea snail is proposed as a sentinel for trace metals, PCBs and OCPs in the coastal lagoons, not only due to its bioaccumulation and biomagnification capacity but also the easy sampling and amply distribution in many coastal areas.

The distribution of per- and polyfluoroalkyl substances (PFAS), alkylphenols, organotin compounds, phthalates, alkylated polycyclic aromatic hydrocarbons, current-use pesticides (CUPs) and personal care products (PCPs) was characterized in 29 surface sediments from two Spanish Iberian continental shelf areas (14 on the Atlantic and 15 on the Mediterranean coasts). Concretely, 115 organic contaminants were determined and a specific methodology was used for each contaminant group, including contaminants of emerging concern (CECs) and traditional ones, such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorinated pesticides (OCPs). PAHs, alkylated PAHs, alkylphenols and phthalates were found in all samples, showing mean concentrations per group higher than 20 ng/g (16-4974 ng/g d.w.) in the subregions under consideration (Galician, Cantabrian, Levantine-Balearic and Strait-Alboran). CUPs and PCPs were found in the majority of samples at very low concentrations of ng/g (1.4-46.8 ng/g d.w.), whereas organotins and PFAS were found principally in sediments from the Mediterranean subregions (2.5-3.9 ng/g d.w.). Different distribution patterns were observed for the contaminant groups and subregions under consideration as a consequence of the diverse predominant sources (industrial, urban, transport and agricultural activities) and environmental behavior (mainly hydrophobicity and persistence). Risk assessment confirmed the impact of phthalates, alkylphenols, PAHs and PCBs on Atlantic ecosystems and of alkylphenols, chlorpyrifos, phthalates, TBT, PAHs, OCPs and PCBs on the Mediterranean ones. Furthermore, the presence of CUPs, PCPs and PFAS in sediments from the Spanish continental shelf located between 2 and 31 km from the coast suggested that those contaminants may also provoke adverse effects on coastal marine ecosystems between their sources and their depositional areas. CAPSULE: Alkylphenols, phthalates and organotins may provoke

The levels and trends of organochlorine contaminants were determined along the Spanish Mediterranean coast from 2000 to 2013 using mussel, Mytilus galloprovincialis, as bioindicator species. The highest levels of PCBs and DDTs were found at industrial and urban locations, and at areas under the influence of the mouth of major rivers. Dieldrin and t-NNC were commonly detected, while HCHs, aldrin, isodrin, endrin and HCB were at levels not detectable at many areas. Significant declines on the levels of DDTs were observed at most of the areas studied. Conversely, no trends or weak downtrends for PCBs were observed in the areas more polluted by local sources, and in most areas less polluted, where PCBs inputs may be primarily from the atmosphere. Upward trends for PCBs were found in some areas from the Albor an Sea, probably related to the inputs of PCBs through the Strait of Gibraltar. Background concentrations for PCBs and p,p’-DDE have been calculated for this Mediterranean region.