ACS ES&T water最新文献

With a long evolutionary history and a need to adapt to a changing environment, cyanobacteria in freshwater systems use specialized metabolites for communication, defense, and physiological processes. Furthermore, many cyanobacterial specialized metabolites and toxins present significant human health concerns due to their liver toxicity and their potential impact to drinking water. Gaps in knowledge exist with respect to changes in species diversity and toxin production during a cyanobacterial bloom (cyanoHAB) event; addressing these gaps will improve understanding of impacts to public and ecological health. In the current report we detail community and toxin composition dynamics during a late bloom period. Species diversity decreased at all study sites over the course of the bloom event, and toxin production reached a maximum at the midpoint of the event. We also isolated three new microcystins from a Microcystis dominated bloom (1–3), two of which contained unusual doubly homologated tyrosine residues (1 and 2). This work provokes intriguing questions with respect to the use of allelopathy by organisms in these systems and the presence of emerging toxic compounds that can impact public health.

Activated carbon (AC) is a cornerstone in water treatment technologies and is renowned for its robust ability to eliminate a wide range of contaminants. However, the adsorption capability of AC diminishes over time and eventually reaches saturation. Given environmental and economic considerations, the regeneration of spent AC emerges as a preferable option. Advanced oxidation processes (AOPs) have been considered a promising approach for spent AC regeneration due to their high efficiency in degrading organic pollutants. This review provides an overview of established AOPs technologies for AC regeneration, elucidating their regeneration mechanisms and key influencing factors. A critical comparison of physicochemical transformations in postregeneration AC and the regeneration efficiency through various AOPs technologies is presented. Moreover, the review addresses some common overlooks in AC regeneration experimental designs and explores the scalability of AOPs regeneration technologies. Finally, future research directions were suggested to improve the AOPs-based regeneration technologies.

Artisanal and small-scale gold mining (ASGM) is a major source of mercury (Hg) contamination in Amazonian ecosystems, due to remobilization of geogenic Hg from mined soil, and anthropogenic Hg used for gold amalgamation. To assess these two relative contributions, Hg stable isotope composition together with geochemical variables were determined in sediment samples collected in the early 2000s across the main watersheds of French Guiana. Mercury in sediment was found associated with organic matter and Fe/Al oxides. Total Hg concentrations were correlated (p < 0.001) to both mass-dependent (δ²⁰²Hg) and odd-mass-independent fractionation (Δ¹⁹⁹Hg) indicating that the Hg isotopic composition of river sediments reflects the extent of contamination, with two isotopic end-members for pristine or geogenic (δ²⁰²Hg = −2.53 ± 0.23‰, Δ¹⁹⁹Hg = −0.62 ± 0.10‰) and for ASGM contaminated (δ²⁰²Hg = −0.42 ± 0.20‰, Δ¹⁹⁹Hg = −0.01 ± 0.07‰) sediments. A binary mixing model showed that the contribution of anthropogenic Hg in river sediments varied widely (ca. 0 to 100%) and reflected the geographical and historical monitoring of ASGM activities in French Guiana. These results highlight that Hg isotopic measurements in archived sediments allow retrospective assessment of Hg pollution in ASGM-impacted regions and evaluation of its temporal evolution.

Global warming and climate change have created various problems, one of which is the increase in harmful algal blooms (HABs) in freshwater systems. Annually, numerous freshwater bodies experience cyanobacterial HABs, which pose significant ecological and public health risks. In this study, we investigated a novel strategy for controlling cyanobacteria by inhibiting CO₂ fixation using glycolaldehyde (GLA) as a nonoxidative algicide. After treatment of Microcystis aeruginosa (M. aeruginosa), a model cyanobacterium, with various doses of GLA, changes in cell number and biomass were observed, along with alterations in the photochemical efficiency of Photosystem II and electron transfer processes in M. aeruginosa, as measured through chlorophyll a fluorescence transients. Treatment with GLA concentrations of 2.5 mM and above completely suppressed the growth and photosynthesis of the M. aeruginosa cells. However, the use of 0.5 mM GLA led to a hormetic effect in M. aeruginosa. When GLA was tested on cyanobacteria-laden water samples collected from a lake, primarily consisting of colonial M. aeruginosa cells, the obtained results indicated that GLA is equally effective against them. These results suggest that GLA could potentially control both M. aeruginosa and other phytoplankton. Our findings led us to consider target-specific approaches for the control and mitigation of cyanobacterial HABs.

Climate change causes sea levels to rise, threatening the lives of people living on coastal islands. However, none has studied how communities can adapt to the changing environment and build climate resilience. To address this issue, the work unlocks adaptation strategies for climate-induced sea level rise in coastal islands. The Thousand Islands (Indonesia) was used as a case study due to their low-lying areas and reliance on agriculture. This work identifies best practices and local challenges due to climate change that could be applicable to other coastal regions. Data collection was undertaken through semistructured interviews with stakeholders. It is evident that adaptation strategies in coastal regions need to be participatory due to the importance of local knowledge and community empowerment. Community’s adaptation initiatives include mangrove restoration and giant seawall construction. There was a 15% increase in species richness and a 10% increase in ecosystem resilience in areas where adaptive measures were applied. The barriers of climate adaptation cover the lack of resources and institutional constraints. It is crucial for the government to collaborate with stakeholders to implement climate adaptation strategies based on local needs. Overall, this work highlights the need for regional collaboration to tackle climate impacts on the rising sea level in coastal areas.

Conventional chemical monitoring using grab samples can hardly reflect the highly dynamic trends in the pollution in estuaries. Here, we examined the bioaccumulation characteristics of organic contaminants based on a 6-year (2015–2020) oyster biomonitoring campaign in the Pearl River Estuary. Using target and suspect analyses, 198 out of ∼1000 organic contaminants were detected with sum concentrations reaching 37,912 ng/g dry wt. By examining diverse contaminants with logK_ow ranging from −0.22 to 15 and half-life ranging from 2.6 to 379 d, distinct season-dependent bioaccumulation was recognized across chemical hydrophobicity and persistence. Approximately twice more contaminants with high hydrophobicity (logK_ow > 6) and half-life >10 d exhibited higher bioaccumulation during the wet season. Geographically, about two-fold more contaminants with moderate and high hydrophobicity exhibited higher levels in oysters from the more urbanized eastern coast than the western coast. The inclusion of diverse suspect analytes in biomonitoring helped to reveal chemical- and season-dependent bioaccumulation characteristics of organic contaminants in highly dynamic estuaries.

Emerging contaminants (ECs) are increasingly discharged into the aquatic environment and cannot be removed by conventional water treatment processes. The detection of various disinfection byproducts (DBPs) originating from ECs as possible precursors is challenging. Herein, liquid chromatography coupled with time-of-flight mass spectrometry was used for the suspect and nontarget screening of ECs and DBPs simultaneously in the effluent of drinking water treatment plants and distribution systems. Forty-one ECs and 27 DBPs were identified, corresponding to different confidence levels (1–3). Pesticides, pharmaceuticals, and personal care products accounted for approximately 63% of the ECs. Halophenols and halonitrophenols were the predominant categories of aromatic DBPs. Three EC species [4-nitrophenol, 3-methyl-4-nitrophenol, and enrofloxacin] and their confirmed DBPs [2,6-dichloro-4-nitrophenol, 2-bromo-6-chloro-4-nitrophenol, 2,6-dibromo-4-nitrophenol, 2-bromo-4-nitrophenol, and 3-chloro-5-(chloromethyl)-4-nitrophenol] were simultaneously detected in the drinking water distribution system. The intensity of aromatic DBPs initially increased and then decreased with transportation in branched drinking water distribution systems, consistent with the quantification results. Thus, the transportation process in drinking water distribution systems impacts DBP formation.

Biological wastewater treatment relies on microorganisms that grow as flocs, biofilms, or granules for efficient separation of biomass from cleaned water. This biofilm structure emerges from the interactions between microbes that produce, and are embedded in, extracellular polymeric substances (EPS). The true composition and structure of the EPS responsible for dense biofilm formation are still obscure. We conducted a bottom-up approach utilizing advanced glycomic techniques to explore the glycan diversity in the EPS from a highly enriched “Candidatus Accumulibacter” granular sludge. Rare novel sugar monomers such as N-Acetylquinovosamine (QuiNAc) and 2-O-Methylrhamnose (2-OMe-Rha) were identified to be present in the EPS of both enrichments. Further, a high diversity in the glycoprotein structures of said EPS was identified by means of lectin based microarrays. We explored the genetic potential of “Ca. Accumulibacter” high quality metagenome assembled genomes (MAGs) to showcase the shortcoming of top-down bioinformatics based approaches at predicting EPS composition and structure, especially when dealing with glycans and glycoconjugates. This work suggests that more bottom-up research is necessary to understand the composition and complex structure of EPS in biofilms since genome based inference cannot directly predict glycan structures and glycoconjugate diversity.

Unveiling novel glycans in ″Ca. Accumulibacter” EPS elucidates crucial insights into environmental bacterial interactions, influencing wastewater treatment efficiency and microbial community dynamics.