Occurrence and distribution of estrogenic substances in the northern South China Sea

Spatiotemporal variations and risk assessment of estrogens in the water of the southern Bohai Sea: A comprehensive investigation spanning three years

The ubiquitous and adverse effects of estrogens have aroused global concerns. Natural and synthetic estrogens in 255 water samples from the southern Bohai Sea were analyzed over three years. Total estrogen concentrations were 11.0-268 ng/L in river water and 1.98-99.7 ng/L in seawater, with bisphenol A (BPA) and 17α-ethynylestradiol (EE2) being the predominant estrogens, respectively. Estrogen showed the highest concentrations in summer 2018, followed by spring 2021 and spring 2019, which was consistent with the higher estrogen flux from rivers during summer. Higher estrogen concentrations in 2021 than in 2019 were driven by the higher level of BPA, an additive used in personal protective equipment. Estrogen exhibited higher concentrations in the southern coast of the Yellow River Delta and the northeastern coast of Laizhou bay due to the riverine input and aquaculture. Estrogens could disturb the normal endocrine activities of organisms and edict high ecological risks (90th simulated RQT > 1.0) to aquatic organisms, especially to fish. EE2 was the main contributor of estrogenic potency and ecological risk, which requires special concern. This is the first comprehensive study of estrogen spatiotemporal variations and risks in the Bohai Sea, providing insights into the environmental behavior of estrogens in coastal regions.

Summary recommendations on "Analytical methods for substances in the Watch List under the Water Framework Directive"

The Watch List (WL) is a monitoring program under the European Water Framework Directive (WFD) to obtain high-quality Union-wide monitoring data on potential water pollutants for which scarce monitoring data or data of insufficient quality are available. The main purpose of the WL data collection is to determine if the substances pose a risk to the aquatic environment at EU level and subsequently to decide whether a threshold, the Environmental Quality Standards (EQS) should be set for them and, potentially to be listed as priority substance in the WFD. The first WL was established in 2015 and contained 10 individual or groups of substances while the 4th WL was launched in 2022. The results of monitoring the substances of the first WL showed that some countries had difficulties to reach an analytical Limit of Quantification (LOQ) below or equal to the Predicted No-Effect Concentrations (PNEC) or EQS. The Joint Research Centre (JRC) of the European Commission (EC) organised a series of workshops to support the EU Member States (MS) and their activities under the WFD. Sharing the knowledge among the Member States on the analytical methods is important to deliver good data quality. The outcome and the discussion engaged with the experts are described in this paper, and in addition a literature review of the most important publications on the analysis of 17-alpha-ethinylestradiol (EE2), amoxicillin, ciprofloxacin, metaflumizone, fipronil, metformin, and guanylurea from the last years is presented.

Distribution, risk assessment, and quantitative source apportionment of heavy metals in surface sediments from the shelf of the northern South China Sea

The concentration of heavy metals (Cu, Pb, Zn, Cr, Co, and Ni) from 421 sediment samples from the shelf of the northern margin of the South China Sea (SNSCS) was analyzed. The heavy metal content and calculated potential ecological indicators (E_rⁱ < 40 and RI < 160) indicate that there is low potential ecological risk of heavy metal pollution in the SNSCS. The mean effects range-median quotient (M-ERM-Q) and hazard quotient (HQ) values of sediment toxicological characteristics indicate that heavy metals are a potential toxicological risk. The high-risk area is mainly distributed in the southwest of the nearshore SNSCS. The positive matrix factorization (PMF) analysis results showed that major contributors to heavy metal pollution were natural sources and anthropogenic activities in the SNSCS. The government should pay particular attention to the monitoring of heavy metals in the nearshore southwest of the SNSCS.

Spatial-temporal occurrence of contaminants of emerging concern in urban rivers in southern Brazil

The widespread use and misuse of antibiotics and pesticides has been linked with several risks to the environment and human health. In the present report, the results of the monitoring of 64 pharmaceuticals and 134 pesticides occurrence in an urban river in Southern Brazil are presented and discussed. Sampling campaigns have covered the period 2016-2018. The identification and determination of the analytes were achieved by high-resolution mass spectrometry. The data were analyzed using chemometric tools to obtain spatial-temporal models. Toxicological evaluation was achieved using acute toxicity (zebrafish standardized protocol), and determination of risk quotient. Within the 198 analytes included in the targeted analysis method for surface water, 33 were identified in an urban river during 2 years of monitoring, being 20 pharmaceuticals and 13 pesticides. Using high-resolution mass spectrometry, a suspect screening approach was established in an un-target analysis. The evaluation was carried out using a data bank built from consumption data of drugs and pesticides, in the metropolitan region of Porto Alegre - RS and their respective metabolites. The suspect screening analysis done with a data bank with more than 1450 compounds results in 27 suspect findings. The target analysis results showed a continuous prevalence of non-steroidal anti-inflammatories, analgesics, antipyretics, beta-blockers, corticoids, and antibiotics. Regarding the pesticides, the main classes were fungicides, especially those from triazol and strobilurin classes.

Investigation of free and conjugated estrogen fate and emission coefficients in three duck farms

Concentration animal feeding operation (CAFO) is an important source of environmental estrogen. However, to the best of our knowledge, the data on estrogen discharge during duck breeding and growth is insufficient. This study used liquid chromatography with tandem mass spectrometry (LC/MS/MS) to analyze the free and conjugated estrogen concentrations in the surface water, outlet water, groundwater, and duck manure/soil mixture at three duck farms in Taiwan. Natural estrogen species included estrone (E1), 17β-estradiol (E2), estriol (E3), estrone-3-sulfate (E1-3S), 17β-estradiol-3-sulfate (E2-3S), estrone-3-glucuronide (E1-3G), and 17β-estradiol-3-glucuronide (E2-3G), whereas synthetic estrogen included 17α-ethynylestradiol (EE2) and diethylstilbestrol (DES). This study showed that the total estrogen concentrations in the surface water and groundwater were 15.4 and 4.5 ng/L, respectively, which constituted 56% and 58%, respectively, conjugated estrogen. From the pond to the outlet water, the total estrogen concentration decreased by 3.9 ng/L (23% loss) in the duck farms. However, the estrogenic potency was slightly reduced from 0.91 to 0.88 E2 equivalent/L, showing a negligible decrease. From the pond to the outlet water, the field results showed that converting the conjugated estrogen into free estrogen in the duck farm-released water increased their environmental hazard. Primarily E1, with an average concentration of 0.9 ± 1.6 ng/g, was present in the duck manure. The estrogen excreted by the ducks in the pond (from surface water to outlet water) was estimated to be 0.18 kg/million head-year. Although the estrogen concentration in the duck farms was low, the environmental impact of CAFO should not be neglected.

Robust strategies to eliminate endocrine disruptive estrogens in water resources

The widespread occurrence and ubiquitous distribution of estrogens, i.e., estrone (E1), estradiol (E2), and estriol (E3) in our water matrices, is an issue of global concern. Public and regulatory authorities are concerned and placing joint efforts to eliminate estrogens and related environmentally hazardous compounds, due to their toxic influences on the environmental matrices, ecology, and human health, even at low concentrations. However, most of the available literature is focused on the occurrence of estrogens in different water environments with limited treatment options. Thus, a detailed review to fully cover the several treatment processes is needed. This review comprehensively and comparatively discusses many physical, chemical, and biological-based treatments to eliminate natural estrogens, i.e., estrone (E1), estradiol (E2), and estriol (E3) and related synthetic estrogens, e.g., 17α-ethinylestradiol (EE2) and other related hazardous compounds. The covered techniques include adsorption, nanofiltration, ultrafiltration, ultrasonication, photocatalysis of estrogenic compounds, Fenton, Fenton-like and photo-Fenton degradation of estrogenic compounds, electro-Fenton degradation of estrogenic compounds, ozonation, and biological methods for the removal of estrogenic compounds are thoroughly discussed with suitable examples. The studies revealed that treatment plants based on chemical and biological approaches are cost-friendly for removing estrogenic pollutants. Further, there is a need to properly monitor and disposal of the usage of estrogenic drugs in humans and animals. Additional studies are required to explore a robust and more advanced oxidation treatment strategy that can contribute effectively to industrial-scale applications. This review may assist future investigations, monitoring, and removing estrogenic compounds from various environmental matrices. In concluding remarks, a way forward and future perspectives focusing on bridging knowledge gaps in estrogenic compounds removal are also proposed.

Microplastic occurrence in the northern South China Sea, A case for Pre and Post cyclone analysis

Microplastics (MPs) have become a great concern owing to their persistence and ecotoxicity in various environmental compartments. MPs can be transported from land to oceans via the aquatic system, and the oceans are believed to be the final sink for MPs. To resolve the lack of data concerning MP contamination in the northern South China Sea (NSCS), coastal seawater and sediments were investigated. The sample sites included the coastal area from Hong Kong to western Guangdong Province, which provided a representative coverage of variable distance to the shore. MP particles were observed in all samples, suggesting a widespread MP pollution in NSCS. The average MP abundance was relatively high in South China Sea, but it was lower than that in other Chinese coastal areas. In all samples, the dominant MP polymer was polyethylene terephthalate fibers. No statistically significant correlation was found between the abundances of MPs in seawater and sediment. The MP distribution in surface water affected by the monsoon exhibited high abundance in the east and low in the west, and MPs were more abundant near the shore than away from it. The tropical cyclone had no obvious effect on the overall MP abundance except in the Hong Kong west marine water (R4), which may attribute to proximity to Hong Kong and other islands.

Occurrence, sources and environmental risk assessment of pharmaceuticals in the Sea of Marmara, Turkey

In the present study, the occurrence and spatial distribution of selected eleven pharmaceuticals were investigated in the Sea of Marmara, Turkey. Samples were collected from different depths of the nine stations in April and October 2019. Pharmaceuticals were analyzed using liquid-liquid and solid-phase extraction (SPE) methods followed by high-performance liquid chromatography (HPLC). All target pharmaceutical compounds were detected at least once in the study area. Gemfibrozil, which belongs to the lipid regulatory group, was the most frequently detected in seawater at high concentrations (<0.016-9.71 μg/L). Ibuprofen (<0.015-2.13 μg/L) and 17α-ethynylestradiol (<0.010-3.55 μg/L) were identified as the other frequently detected pharmaceuticals. In addition, the presence of these selected compounds in April was higher than in October. According to the risk assessment results, naproxen, diclofenac, clofibric acid, gemfibrozil, 17β-estradiol, and 17α-ethynylestradiol represent a high risk to aquatic organisms in the Sea of Marmara. These findings underline the importance of continued monitoring of these compounds as relevant organic contaminants in the study area to take appropriate measures to protect the ecosystem and, ultimately, human health.

Suppression mechanism of model humic constituents on laccase-enabled 17β-estradiol oxidation and oligomerization

Humic constituents (HCs) are ubiquitous in the aquatic ecosystems, and contain various functional groups that seriously impact the conversion of 17β-estradiol (17β-E2) by fungal laccase. The purpose of this study was to explore the influencing mechanism of HCs on Trametes versicolor laccase-enabled 17β-E2 oxidation and oligomerization. Herein, T. versicolor-secreted laccase could rapidly convert 99.2% of 17β-E2 (rate constant = 3.7 × 10^-2 min^-1, half-life = 18.7 min) into multifarious oligomers at 25 °C and pH 5.0, by phenolic radical-caused C-C and/or C-O self-linking routes, whereas HCs with O-phenolic hydroxyl groups (O-p-OH, i.e., catechol, pyrogallol, gallic acid, and caffeic acid) dramatically suppressed 17β-E2 oligomerization. Compared with HC-free, 17β-E2 rate constants weakened 6.3-15.8 fold in the presence of HCs containing O-p-OH. It is largely because the O-p-OH was preferentially oxidized by T. versicolor laccase to create the electrophilic O-quinone monomers/oligomers. These unstable reactive O-quinone intermediates strongly reversed 17β-E2 phenolic radicals to their monomeric molecules via two proton-transfer versus two electron-transfer channels, thus intercepting 17β-E2 oxidation and oligomerization. These findings highlight new insights into the effect of HCs containing O-p-OH on T. versicolor laccase-started 17β-E2 conversion, which is beneficial to re-understanding the fate and geochemical behavior of 17β-E2 in water.

Recognition and Selectivity Analysis Monitoring of Multicomponent Steroid Estrogen Mixtures in Complex Systems Using a Group-Targeting Environmental Sensor

The same class of steroid estrogen mixtures, coexisting in the environment of 17β-estradiol, estrone (E1), and ethinyl estradiol (EE2), have strong ability to disrupt the human endocrine system and are seriously prejudicial to the health of the organism and environmental safety. Herein, a highly sensitive and group-targeting environmental monitoring sensor was fabricated for a comprehensive analysis of multicomponent steroid estrogens (multi-SEs) in complex systems. This breakthrough was based on the highly sensitive photoelectrochemical response composite material CdSe NPs-TiO₂ nanotube and highly group-specific aptamers. The optimized procedure exhibited not only high sensitivity in a wide range of concentrations from 0.1 to 50 nM, indeed, the minimum detection limit was 33 pM, but also strong resistance to interference. The affinity and consistent action pockets of this sensor enable selective detection of multi-SEs in complex systems. It subsequently was applied for the analysis of multi-SEs from three real samples in the environment including medical wastewater, river water, and tap water to provide a means to clarify the fate of multi-SEs in the process of migration and transformation. This monitoring sensor has a brilliant application prospect for the identification and monitoring of the same class of endocrine-disrupting chemical mixtures in environmental complex systems.

Endocrine-Disrupting Compounds: An Overview on Their Occurrence in the Aquatic Environment and Human Exposure

Endocrine-disrupting compounds (EDCs) as emerging contaminants have accumulated in the aquatic environment at concentration levels that have been determined to be significant to humans and animals. Several compounds belong to this family, from natural substances (hormones such as estrone, 17-estradiol, and estriol) to synthetic chemicals, especially pesticides, pharmaceuticals, and plastic-derived compounds (phthalates, bisphenol A). In this review, we discuss recent works regarding EDC occurrence in the aquatic compartment, strengths and limitations of current analytical methods used for their detection, treatment technologies for their removal from water, and the health issues that they can trigger in humans. Nowadays, many EDCs have been identified in significant amounts in different water matrices including drinking water, thus increasing the possibility of entering the food chain. Several studies correlate human exposure to high concentrations of EDCs with serious effects such as infertility, thyroid dysfunction, early puberty, endometriosis, diabetes, and obesity. Although our intention is not to explain all disorders related to EDCs exposure, this review aims to guide future research towards a deeper knowledge of EDCs’ contamination and accumulation in water, highlighting their toxicity and exposure risks to humans.