This review examines the aims of and approaches to the Quantitative Microbial Risk Assessment (QMRA) of untreated recreational waters. The literature search was conducted on four databases and yielded 54 papers, which were analyzed on a quantitative (time-trend, geographical distribution, water type) and qualitative (aims, source of microbial data, pathogens and their measurement or estimation, ways to address variability and uncertainty, sensitivity analysis) basis. In addition, the parameters, implications, and limitations were discussed for each QMRA step. Since 2003, the number of papers has greatly increased, highlighting the importance of QMRA for the risk management of recreational waters. Nevertheless, QMRA still exhibits critical issues, above all regarding contamination data and dose-response relationships. To our knowledge, this is the first review to give a wide panoramic view on QMRA in relation to recreational exposure to untreated waters. This could be useful in identifying the current knowledge gaps and research needs.

In this study, a general methodology that is based on numerical models and statistical analysis is developed to assist in the definition of marine litter cleanup and mitigation strategies at an estuarine scale. The methodology includes four main steps: k-means clustering to identify representative metocean scenarios; dynamic downscaling to obtain high-resolution drivers with which to force a transport model; numerical transport modelling to generate a database of potential litter trajectories; and a statistical analysis of this database to obtain probabilities of litter accumulation. The efficacy of this methodology is demonstrated by its application to an estuary along the northern coast of Spain by comparing the numerical results with field data. The necessary criteria to ensure its applicability to any other estuary were provided. As the main conclusion, the developed methodology successfully assesses the litter distribution in estuaries with minimum computational effort.

Ten pharmaceutically active compounds (PhACs) were determined in northern Taiwan estuarine waters and Taiwan Strait (TS) seawater. The ecological risk of these PhACs was assessed using risk quotient (RQ), which is the ratio of the measured maximum concentration to the predicted no-effect concentration. Six PhACs were detected within the estuarine waters. Caffeine concentration (130–718 ng l⁻¹) was the highest among the analyzed PhACs. The distribution of PhACs in the Danshuei River Estuary generally exhibited addition behavior, except that caffeine showed conservative behavior. Carbamazepine, gemfibrozil, caffeine, and ketoprofen were detected in TS seawaters. Their concentrations follow the sequence: gemfibrozil > ketoprofen > caffeine > carbamazepine. The caffeine concentrations in TS seawaters were 2–3 orders of magnitude lower than those in Danshuei estuarine waters. With few exceptions for caffeine, erythromycin, and sulfadiazine posing low risk in some estuarine waters, most of the RQ values were <0.01, suggesting no adverse effects on aquatic organisms.

The effects of nutrient distribution and structure on the behavior and speciation of dissolved inorganic arsenic (DIAs) in coastal waters were analyzed based on the data of 48 surface water samples collected in the southwestern coast of Laizhou Bay and its adjacent rivers (SWLZB). The concentration of DIAs in the SWLZB ranged from 0.016 to 0.099 μmol l⁻¹ and generally decreased from west to south. The inshore waters exhibited higher DIAs level than the open ocean. The As⁵⁺/As³⁺ ratio was significantly positively correlated with the concentration of TDN, NO₃-N, PO₄-P, DSi, Chl-a and DO. The concentration of DIAs was strongly correlated with the concentration of PO₄-P and DSi, suggesting that adsorption/desorption was an important process for regulating the total DIAs concentration. The results indicated that the distribution of nutrients might well be an important environmental factor affecting the speciation and behavior of DIAs in surface water of the SWLZB.

The objective of the present study was to test whether the Atlantic ghost crab Ocypode quadrata is a reliable biomonitor of microplastic (MP) pollution of beach sediments. To test the hypothesis (H1) that the sediment is the main source of MP ingestion, the proportion of MP types (hard plastic, microfibers, pellet, soft plastic, and extruded polystyrene foam) in the gut content was compared with that on the strandline. The types of MPs in the gut content and sediment had similar proportions; black (~49%) and blue (~45%) microfibers were responsible for this similarity (55%), hence confirming H1. However, the second hypothesis (H2) that prevalence of MP in the gut content is related to its density on beach with distinct urbanization degree was not accepted. These results indicate that high trophic plasticity of the ghost crab and, consequently, multiple-sources of contamination may interfere with its use as a biomonitor of MP pollution.

Oxidant treatment of ballast water (BW) is commonly used in BW systems in order to minimize the transport of alien species. The release of disinfection by-products (DBPs) associated to the treatment of BW and cross-contamination of butyltin (BT) compounds through BW discharge is a topic of environmental concern. A chemical port baseline survey has been conducted in seven ports of the Adriatic Sea. Analysis have been performed on transplanted mussels, surface sediment, seawater, BW. Results showed an evidence of BT contamination, particularly in sediments, probably related to their illegal usage or to intensive shipping activities. Therefore, BW may act as a vector and contribute to re-buildup of BT contamination in the coastal regions.A baseline set of data concerning DBPs is provided, showing the preferential distribution of these compounds in the marine environment that will be useful for future considerations on monitoring and assessment of chemical contamination associated with BW.

A suite of eight polyhalogenated carbazole (PHCZ) congeners were detected in sediments of the Jiaozhou Bay wetland. 3,6-dichlorocarbazole (36-CCZ), and 3,6-dibromocarbazole (36-BCZ) were detected in all samples. The concentrations of ΣPHCZs ranged from 6.9 to 33.4 ng/g dry weight (dw). The recovery of surrogate standard ranged from 85 to 109%. Significant relationships were found between the concentrations of 36-CCZ and those of the other three detected compounds (36-BCZ, 36-ICZ, and 1368-BCZ). However, with regard to the other chemicals, only 1368-BCZ was related to 36-ICZ. The toxic equivalent (TEQ) was used to assess the relative toxicity of PHCZs, which ranged within 0.1–3.9 pg TEQ/g dw in sediment. The inventory of ΣPHCZs was 58.9 kg. These results indicate that PHCZs are widely distributed in the Jiaozhou wetland and the dyeing and finishing industries may be important contamination sources of PHCZs.

Metal/metalloid concentrations in water sediment and commercial fishes of Loreto Maritime National Park (MNP), Baja California Sur, Mexico were determined for a comprehensive geochemical study. In-situ physical characteristics (pH, conductivity, redox potential, dissolved oxygen, turbidity) of water clearly indicated the unique oceanographic properties of the Gulf of California. Likewise, the distribution pattern of metals/metalloid in water, sediments and fishes denoted the influences of local geology, longshore currents, upwelling process, natural hydrothermal vents and the 100-year old mining activities of Santa Rosalia region, situated to the north of Loreto. Calculated carcinogenic indices in commercial fish species showed safe human consumption. Thus, the present research validates a comprehensive geochemical study of protected areas upholding the need for continuous monitoring for a better conservation of coastal ecosystems.

Historically solid waste was commonly landfilled in the coastal zone in sites with limited engineering to isolate waste from adjacent coastal environments. Climate change is increasing the likelihood that these historic coastal landfills will erode releasing solid waste to the coastal zone. Historic coastal landfills are frequently located near designated ecological sites; yet, there is little understanding of the environmental risk posed by released waste. This research investigated inorganic and organic contaminant concentrations in a range of solid waste materials excavated from two historic coastal landfills, and the potential ecological impact should eroded waste be released to the coastal environment. Contaminant concentrations in the analysed waste materials exceeded sediment quality guidelines, indicating erosion of historic coastal landfills may pose a significant environmental threat. Paper and textile wastes were found to make a significant contribution to the total contaminant load, suggesting risk assessments should consider a wide range of solid waste materials.

In situ studies of plastic deterioration can help us understand the longevity of macroplastic as well as the generation of microplastics in the environment. Photo-oxidation contributing to the generation of microplastics in the marine environment was explored using four types of plastic (polyethene, polystyrene, poly(ethylene terephthalate) and Biothene® exposed in light and in shade, in both air and sea water. Metrics for deterioration were tensile extensibility and oxidation rate. Measurements were conducted at intervals between 7 and 600 days' exposure. Deterioration was faster in air than in sea water and was further accelerated in direct light compared to shade. Extensibility and oxidation were significantly inversely correlated in samples exposed in air. Samples in sea water lost extensibility at a slower rate. Polystyrene, which enters the waste stream rapidly due to its wide application in packaging, deteriorated fastest and is, therefore, likely to form microplastics more rapidly than other materials, especially when exposed to high levels of irradiation, for example when stranded on the shore.