Surface Water Concentrations Research Articles

Antibiotics in the rice-crayfish rotation pattern: Occurrence, prioritization, and resistance risk

Antibiotics are extensively utilized in aquaculture to mitigate diseases and augment the productivity of aquatic commodities. However, to date, there have been no reports on the presence and associated risks of antibiotics in the emergent rice-crayfish rotation (RCR) system. This study investigated the occurrence, temporal dynamics, prioritization, sources, and potential for resistance development of 15 antibiotics within the RCR ecosystem. The findings revealed that during the crayfish breeding and rice planting periods, florfenicol (FFC) predominated in the RCR's surface water, with peak and average concentrations of 1219.70 ng/L and 57.43 ng/L, and 1280.70 ng/L and 52.60 ng/L, respectively. Meanwhile, enrofloxacin (ENX) was the primary antibiotic detected in RCR soil and its maximum and average concentrations were 624.73 ng/L and 69.02 ng/L in the crayfish breeding period, and 871.27 ng/L and 45.89 ng/L in the rice planting period. Throughout the adjustment period, antibiotic concentrations remained relatively stable in both phases. Notably, antibiotic levels in surface water and soil escalated during the crayfish breeding period and subsided during the rice planting period, with these fluctuations predominantly influenced by FFC and ENX. Source analysis indicated that the antibiotics in RCR predominantly originated from aquaculture activities, supplemented by water exchange processes. Utilizing the entropy utility function and a resistance development model, FFC, clarithromycin (CLR), and roxithromycin (ROX) in surface water, along with ENX, CLR, and ROX in soil, were identified as priority antibiotics. FFC, ENX, and ROX exhibited a medium risk for resistance development. Consequently, this study underscores the necessity to intensify antibiotic usage control during the crayfish breeding period in the RCR system to mitigate environmental risks.

HydroFATE (v1): a high-resolution contaminant fate model for the global river system

Abstract. Pharmaceuticals and household chemicals are neither fully consumed nor fully metabolized when routinely used by humans, thereby resulting in the emission of residues down household drains and into wastewater collection systems. Since treatment systems cannot entirely remove these substances from wastewaters, the contaminants from many households connected to sewer systems are continually released into surface waters. Furthermore, diffuse contributions of wastewaters from populations that are not connected to treatment systems can directly (i.e., through surface runoff) or indirectly (i.e., through soils and groundwater) contribute to contaminant concentrations in rivers and lakes. The unplanned and unmonitored release of such contaminants can pose important risks to aquatic ecosystems and ultimately human health. In this work, the contaminant fate model HydroFATE is presented, which is designed to estimate the surface-water concentrations of domestically used substances for virtually any river in the world. The emission of compounds is calculated based on per capita consumption rates and population density. A global database of wastewater treatment plants is used to separate the effluent pathways from populations into treated and untreated and to incorporate the contaminant pathways into the river network. The transport in the river system is simulated while accounting for processes of environmental decay in streams and in lakes. To serve as a preliminary performance evaluation and proof of concept of the model, the antibiotic sulfamethoxazole (SMX) was chosen, due to its widespread use and the availability of input and validation data. The comparison of modelled concentrations against a compilation of reported SMX measurements in surface waters revealed reasonable results despite inherent model uncertainties. A total of 409 000 km of rivers were predicted to have SMX concentrations that exceed environmental risk thresholds. Given the high spatial resolution of predictions, HydroFATE is particularly useful as a screening tool to identify areas of potentially elevated contaminant exposure and to guide where local monitoring and mitigation strategies should be prioritized.

Instability evolution of expansive soil slope due to short duration-varying intensities of rainfall

This study examines the evolution of instability in induced expansive soil slopes under varying rainfall intensities. The destabilization evolution of expansive soil slopes and their stability under three different rainfall intensities were revealed through indoor modelling and numerical simulation. The findings indicate that slopes are not destabilized by short duration and low rainfall intensity alone. Slope failure under strong rainfall intensity follows a three-stage evolutionary process. As rainfall intensity increases, the slope's water content, soil pressure, and pore water pressure increase. However, the stress at each monitoring point of the slope affected by rainfall follows a different pattern. Under low rainfall intensity, the water content of the slope surface is higher than that of the slope foot. Under strong rainfall conditions, the water content of the slope foot is higher than that of the slope surface. Therefore, it is important to implement seepage prevention measures on the slope surface and drainage measures on the slope foot to ensure slope stability. Rainfall affects the soil pressure at each monitoring point of the slope, causing unloading on the slope surface and fluctuation at the foot of the slope. This phenomenon becomes more pronounced with increasing rainfall intensity. Numerical simulation confirms that the overall horizontal displacement distance of the slope increases with rainfall intensity, but the horizontal displacement range becomes shallower. The slope's maximum horizontal displacement occurs at its foot, with values of 0.29 m and 0.34 m under moderate and heavy rainfall, respectively, representing a growth rate of 17 %. Settlement of the slope under different rainfall intensities was greatest at the top of the slope area. The lateral stresses generated by the settlement resulted in soil uplift at the leading edge of the slope.

Detection of Autumnal Concentration of Coscinodiscus granii in the Southern Baltic—A Method for In Situ Measurement of Marine Particles

Efficient means for measuring the abundance and species composition of phytoplankton in situ continue to pose a big challenge to scientists. Hitherto, analyses and interpretations have been based mainly on small numbers of data acquired from microscopic examinations of water samples. Hence, information on devices facilitating such measurements is highly desirable. This paper examines the opportunities offered by the LISST-100X instrument for measuring in situ the concentrations and spatially variable biovolumes of a species dominant in the southern Baltic during the autumnal bloom. Microscopic analysis of phytoplankton in water sampled from different locations in the southern Baltic confirmed earlier results, indicating that this bloom was due to the overriding prevalence of one microplankton diatom species—Coscinodiscus granii. Combining the microscopic measurements of C. granii cell sizes with the size distribution ranges employed by the LISST-100X yielded equivalent spherical diameters (EDSs) ranging from 47.4 to 188.0 µm, with maxima in the 78.4–92.6 and 92.6–109 ranges. Comparative analysis of the particle size distribution (PSD) spectra was used to separate the abundance of C. granii from the total suspended particulate matter (SPM). Spatial in situ measurements in 2012 and 2014 of C. granii concentrations in surface waters showed that both its abundance and its percentage contribution to the total SPM were highly variable. Over a distance of several km, these concentrations varied from values close to zero to 0.2 µL L−1 in 2012 and from 0.3 to 0.9 µL L−1 in 2014, whereas the percentage in the total SPM was found to vary locally from a few to c. 50%. The proposed method and results demonstrate the success of the LISST-100X instrument in detecting size and volume concentrations of phytoplankton in size classes ranging from 1.25 to 250 μm. However, the correct interpretation of LISST data requires that the dominant phytoplankton species concentration in the suspensions be large enough for the signal (peak) to be readily visible against the background PSD of other SPM.

Comparison of measured and predicted herbicide concentrations in surface water catchments in Belgium.

In the process of approval of active substances and authorization in the European Union and at the member state level, it must be shown by the applicant that an unacceptable risk for nontarget organisms in the aquatic environment by the active substance can be excluded. To achieve this aim, standardized models, scenarios, and agreed pesticide input parameters have to be used to calculate the exposure as defined by the FOrum for the Co-ordination of pesticide fate models and their Use (FOCUS). During a period of daily surface water sampling lasting 3.5 years, a survey was conducted among farmers in the highly vulnerable catchment of Grote Kemmelbeek in Belgium to collect agronomic data on crops, application dates, and application rates of 12 applied herbicides and one metabolite. Daily surface water concentrations for the same herbicides were measured over 2.5 years for a second, much larger but less vulnerable, catchment of Kleine Aa (KAa). A comparison of realistic worst-case predicted environmental concentrations in surface water (PECsw) according to FOCUS with measured concentrations shows that, in the GKb catchment, the PECsw was never exceeded for six substances, was exceeded on only 1-2 days for five substances, and was exceeded on 9-27 days for two substances. For the KAa catchment, the PECsw was only exceeded on twodays for one compound and never for the other 12 compounds. These numbers correspond to a level of protection of the FOCUS PECsw between 100% and 97% and are much higher than the regulatory protection goal of 90%. These two case studies demonstrate the protectiveness of the FOCUS surface water approach. Integr Environ Assess Manag 2024;20:1447-1462. © 2024 Bayer AG. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Application of standardized methods to evaluate the environmental safety of polyvinyl alcohol disposed of down the drain.

The purpose of this research was to use polyvinyl alcohol (PVOH) 18-88 as a case study to evaluate the environmental fate, ecotoxicity, and overall safety profile of water-soluble, nonmodified PVOH polymers used in detergent films. An OECD 303A Wastewater Treatment Plant Simulation Study was conducted with dissolved organic carbon as the analytical endpoint to evaluate the removal of PVOH 18-88 during wastewater treatment. During the plateau phase, high levels of removal due to biodegradation were observed (average 97.4 ± 7.1, range: 88%-116%). The OECD 303A study quantitatively verified that surface water is the dominant receiving compartment for PVOH 18-88 post wastewater treatment. Acute algae, invertebrate, and fish embryo (fish embryo acute toxicity test [FET]) ecotoxicity studies quanitified the 50% lethal/effect concentration (L/EC50) for PVOH 18-88. Due to the potential for the chorion to impact PVOH 18-88 bioavailability, both chorionated and dechorionated FET tests were conducted. L/EC50 > 1000 mg/L for FET (chorionated and dechorionated), invertebrate, and algae were observed. The Sustainable Futures (US) and REACH (EU) frameworks were used to evaluate environmental risk. For the US assessment, the Exposure and Fate Assessment Screening Tool was used to predict the single day lowest flow over a 10-year period (1Q10) surface water concentration and the seven consecutive days of lowest flow over a 10-year period (7Q10) surface water concentration and compared with acute and chronic concentrations of concern. For the EUassessment, the European Union System for the Evaluation of Substances was used to predict local and regional exposure concentrations and compared to the predicted no effect concentration. For both regulatory assessments, the exposure concentrations were >2 orders of magnitude below the effect concentrations. Integr Environ Assess Manag 2024;20:1693-1705. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Metabolites are overlooked in environmental risk assessments and monitoring of pharmaceuticals: The case study of pantoprazole

The proton-pump inhibitor pantoprazole (PPZ) is one of the most consumed pharmaceuticals worldwide. Despite its high usage, reported PPZ concentrations in environmental water samples are comparatively low, which can be explained by the extensive metabolism of PPZ in the human body. Since most previous studies did not consider human PPZ metabolites it can be assumed that the current environmental exposure associated with the application of PPZ is substantially underestimated. In our study, 4′-O-demethyl-PPZ sulfide (M1) was identified as the predominant PPZ metabolite by analyzing urine of a PPZ consumer as well as the influent and effluent of a wastewater treatment plant (WWTP) using liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS). M1 was found to be ubiquitously present in WWTP effluents (max. concentration: 3 000 ng/L) and surface waters in Germany. On average, the surface water concentrations of M1 were approximately 30 times higher than those of the parent compound PPZ. Laboratory scale experiments demonstrated that activated carbon can considerably adsorb M1 und thus improve its removal during wastewater and drinking water treatment. Laboratory ozonation experiments showed a fast oxidation of M1, accompanied by the formation of several ozonation products. Certain ozonation products (identities confirmed via synthesized reference standards) were also detected in water samples collected after ozonation in a full-scale WWTP. Overall lower signal intensities were observed in the effluents of a sand filter and biologically active granular activated carbon filter, suggesting that the compounds were significantly removed during these post-ozonation treatment stages.

Development of a fast‐response system with integrated calibration for high‐resolution mapping of dissolved methane concentration in surface waters

AbstractDissolved gas concentrations in surface waters can have sharp gradients across marine and freshwater environments, which often prove challenging to capture with analytical measurement. Collecting discrete samples for laboratory analysis provides accurate results, but suffers from poor spatial resolution. To overcome this limitation, water equilibrators and gas membrane contactors (GMCs) have been used for the automated underway measurement of dissolved gas concentrations in surface water. However, while water equilibrators can provide continuous measurements, their analytical response times to changes in surface water concentration can be slow, lasting tens of minutes. This leads to spatial imprecisions in the dissolved gas concentration data. Conversely, while GMCs have proven to have much faster analytical response times, often lasting only a few minutes or less, they suffer from poor accuracy and thus require routine calibration. Here we present an analytical system for the high accuracy and high precision spatial mapping of dissolved methane concentration in surface waters. The system integrates a GMC with a cavity ringdown spectrometer for fast analytical response times, with a calibration method involving two Weiss‐style equilibrators and discrete measurements in vials. Data from both the GMC and equilibrators are collected simultaneously, with discrete vial samples collected periodically throughout data collection. We also present a mathematical algorithm integrating all data collected for the routine calibration of the GMC dataset. The algorithm facilitates comparison between the GMC and equilibrator datasets despite the substantial differences in response times (0.7–2.1 and 4.1–17.6 min, respectively). This measurement system was tested with both systematic laboratory experiments and field data collected on a research cruise along the US Atlantic margin. Once calibrated, this system identified numerous sharp peaks of dissolved methane concentration in the US Atlantic margin dataset that would be poorly resolved, or outright missed with previous measurement techniques. Overall, the precision and accuracy for the technique presented here were determined to be 11.2% and 10.4%, respectively, the operating range was 0–1000 ppm methane, and the e‐folding response time to changes in dissolved methane concentration was 0.7–2.1 min.

Microplastics plastisphere is an important eco-site for nitrous oxide emission in lakes: A case study of various lakes in Wuhan, China

This study used correlation analyses to examine the microbial mechanisms linking microplastics and nitrous oxide (N2O) fluxes in 18 typical lakes in Wuhan city. The microplastic abundances were 502 ± 212 items/m3 in the surface water and 305 ± 216 items/kg in dry sediments. The microplastics were predominantly black and fiber shaped in both surface water and sediments. The N2O flux was positively correlated with total phosphorus (p < 0.01), suspended particles (p < 0.01), total nitrogen (p < 0.05), and dissolved inorganic nitrogen (p < 0.01) in surface water. nirK/nosZ I was negatively correlated with the N2O flux and positively correlated with dissolved N2O concentration in surface water (p < 0.05). The microplastic abundance in surface water was positively correlated with nosZ II in water (p < 0.01) and nirK/nosZ I in sediment (p < 0.001). The microplastics in sediments were negatively correlated with nirK/nosZ I in water (p < 0.001) and positively correlated with nirS in sediment (p < 0.05). The predominant plastisphere denitrifiers in this study were nirS-type in sediments and nirK-type in surface water. The predominant denitrifier in surface water was Flavobacterium, where it had far higher relative abundances compared to sediments. The co-occurrence network between nitrifiers, denitrifiers, and water quality indexes implied that denitrifiers competed strongly in sediments, while they cooperated in surface water. Looking at the whole microbial community, the competitive and cooperative relationships were more complex in the sediment samples. The N2O flux was positively correlated with the plastic degradation function in sediment (p < 0.05), implying the plastisphere was a significant contributor. Microplastics in lakes, i.e., the plastisphere, may be a novel microbial colonization site that could be vital to ecosystem N2O emissions.

Prevalence of Microplastic Pollution in Freshwater Ecosystem: A Case Study of Thal Canal

Microplastic pollution in the aquatic ecosystems is a hot global debate due to wide spread effects on human life and environment. This study aims to identify microplastic pollution presence in the Main Line (ML) Thal canal, its distributaries and provide an overall estimation of microplastics concentration in surface water of Thal Canal. Six major sampling points at ML canal and distributaries were assessed for microplastic prevalence out of which five locations showed microplastic contamination. Size, structure and type of microplastic were assessed using light microscopy and FTIR. The study provided baseline information about the prevalence of microplastics in Thal Canal and evaluated their categories according to their size, color and type of polymers. Microplastics concentration in the canal ranged from 6.4 ± 0.5 to 8.8 ± 0.5 particles/m³. Films, mostly transparent in coloration, were the most prominent microplastic type appeared in this study. Polyethylene with 55% presence was the most prevalent type of microplastics found in the canal and the distributaries. This study provides a better understanding of the extent of microplastic pollution assessment in Thal canal with equal emphasis on Microplastic presence in distributaries which may be beneficial in identifying the introduction of microplastics at sources.

Comprehensive assessment of exposure and environmental risk of potentially toxic elements in surface water and sediment across China: A synthesis study

China faces a serious challenge with water pollution posed by potentially toxic elements (PTEs). Comprehensive and reliable environmental risk assessment is paramount for precise pollution prevention and control. Previous studies generally focused on a single environmental compartment within small regions, and the uncertainty in risk calculation is not fully considered. This study revealed the current exposure status of 11 PTEs in surface water and sediment across China using previously reported concentration data in 301 well-screened articles. Ecological and human health risks were evaluated and the uncertainty related to calculation parameters and exposure dataset were quantified. PTEs of high concern were further identified. Results showed Mn and Zn had the highest concentration levels, while Hg and Cd had the lowest concentrations in both surface water and sediment. Risk assessment of individual PTE showed that high-risk PTEs varied by risk receptors and environmental compartments. Nationwide, the probability of aquatic organisms being affected by Mn, Zn, Cu, and As in surface water exceeded 10 %. In sediment, Cd and Hg exhibited high and considerable risk, respectively. As was identified as the major PTE threatening human health as its carcinogenic risk was 1.45 × 10−4 through direct ingestion. Combined risk assessment showed the PTE mixture in surface water and sediment posed medium and high ecological risk with the risk quotient and potential ecological risk index of 1.76 and 558.36, respectively. Adverse health effects through incidental ingestion and dermal contact during swimming were negligible. This study provides a nationwide risk assessment of PTEs in China's aquatic environment and the robustness is verified, which can serve as a practical basis for policymakers to guide the early warning and precise management of water pollution.

Controls on distributions of aluminium, manganese and cobalt in the South Atlantic Ocean along GEOTRACES transect GA10

Trace metals (TMs) manganese (Mn), cobalt (Co), and aluminium (Al) have important geochemical and biological roles in the ocean. Here, we present full depth profiles of dissolved (d) and particulate Al, Mn, and Co along the latitude of 40 °S in the South Atlantic Ocean from the GEOTRACES GA10 cruises that operated in austral spring 2010 and summer 2011. The region is characterized by enhanced primary productivity and forms a key transition zone between the Southern Ocean and South Atlantic Subtropical Gyre. The mean concentrations of dAl, dCo, and dMn (±standard deviation) were 3.36 ± 2.65 nmol kg−1, 35.3 ± 17.6 pmol kg−1, and 0.624 ± 1.08 nmol kg−1, respectively. Their distributions in surface waters were determined by external sources and complex internal biogeochemical processes. Specifically, surface ocean dCo was controlled by the interplay between phytoplankton uptake, remineralization and external inputs; dMn was likely determined by the formation and photoreduction of Mn-oxides; and dAl was supplied by atmospheric deposition and removed by scavenging onto particles. Fluvial and sedimentary inputs near the Rio de La Plata estuary and benthic sources from the Agulhas Bank resulted in elevated dTM concentrations in near-shore surface waters. These externally sourced dTMs were effectively delivered to the open ocean by offshore diffusion and/or advection, and potentially facilitated enhanced primary productivity along the transect.The distributions of dTMs at depth were predominantly controlled by the mixing of North Atlantic Deep Water (NADW) and waters of Antarctic origin (e.g., Upper Circumpolar Water (UCDW) and Antarctic Bottom Water (AABW)). The calculated endmember concentrations of dAl and dCo in NADW showed minor decreases in the SASTG following north–south transport, suggesting removal rates of 0.064 nM/year and 0.035–0.075 pM/year, respectively. The endmember concentration of dCo in AABW was maintained at ∼30 pmol kg−1 without evidence for scavenging removal in the Southern Ocean and SASTG (time frame >400 years). The concentrations of dMn in NADW and AABW were between 0.1 and 0.16 nmol kg−1, and any elevated dMn concentrations were ascribed to local external inputs (e.g., from sediments in the Argentine Basin and hydrothermal activity near the Mid-Atlantic Ridge). Hence, four controlling factors (sources, internal cycling, water mass mixing and time) need to be considered when assessing TM distributions in the global ocean, even for TMs that are vulnerable to scavenging removal processes. Because the deep waters formed in high latitude oceans are crucial components of the global thermohaline overturning system, any processes (e.g., glacier melting, upwelling and sinking, and biological activity) that impact the preformed dTM concentrations in high latitude oceans will determine the downstream dTM distributions. Therefore, the sources and sinks of TMs and associated biological activity in high latitude oceans could engender basin to global scale impacts on seawater distributions of Al, Co, and Mn and their stoichiometric relationships with macronutrients, and the global biogeochemical cycles of these scavenged-type TMs.

Browning from headwaters to coastal areas in the boreal region: Trends and drivers

Browning of freshwaters, mainly caused by increased terrestrial organic carbon loading, has been widely studied during the last decades. However, there are still uncertainties regarding both the extent of browning in different aquatic ecosystems and the actual importance of different driving forces and mechanisms. To refine understanding of the extent and causes of browning and its temporal variation, we gathered a comprehensive dataset including 746 Finnish water quality monitoring stations representing various waterbody types: streams, rivers, lakes, and coastal waters. Monotonic trend analyses revealed that TOC concentrations increased in all waterbody types during the study period from 1990 to 2020, whereas non-linear trends indicated that upward trends in TOC concentrations have substantially decreased since the mid-2000s. However, despite the upward trends levelling off, non-linear analyses also indicated decreases in TOC concentrations at only a few stations. As a result, the TOC contents of the majority of Finnish waterbody types in 2020 were at a higher level than in 1990. To examine the driving forces of increasing TOC concentrations, we selected 100 riverine catchments and linked the detected trends to 24 different drivers, including both hydrometeorological and catchment characteristics. The increased TOC concentrations in surface waters could be connected to diverse human impacts: hydrometeorological variables impacted by climate change, decreased acidic deposition, and land use in terms of peatland drainage. The importance of increased temperatures was emphasized, and its role as a driver of increased leaching of organic carbon in the forthcoming years is expected to grow with climate change.

Surface Water (SW) and Shallow Groundwater (SGW) Nutrient Concentrations in Riparian Wetlands of a Mixed Land-Use Catchment

Precipitation patterns, water flow direction, and local land-use practices affect surface water (SW) and shallow groundwater (SGW) nutrient concentrations in riparian wetlands. Given physical process complexities, spatiotemporal quantification of nutrients and physical factors influencing nutrient concentrations are needed to advance wetland water resource management. To address these needs, a study was conducted in riparian wetlands of a mixed land-use catchment in West Virginia (WV), USA. Observed data included SW–SGW levels and nutrient concentrations, including nitrate (NO3-N), nitrite (NO2-N), ammonium (NH4-N), orthophosphate (PO43-P), total nitrogen (total_N), and total phosphorus (total_P) from January 2020 to December 2021. Water samples were collected monthly from stream gauge sites (n = 4) and co-located piezometers (n = 13). Results showed that, on average, gaining stream conditions were observed in upstream sites, and losing stream conditions were observed in downstream sites. Observed nutrient profiles between SW and SGW included SW exhibiting a higher average NO3-N concentration (0.42 mg/L), while SGW displayed an elevated NH4-N concentration (1.55 mg/L) relative to other nitrogen species. Significantly high (p &lt; 0.05) SW NO3- concentrations in summer and fall were attributed to increased precipitation and corresponding water level and, therefore, pressure head and transport fluctuations. Principal Component Analysis (PCA) showed differences in nutrient concentrations based on the water source type and catchment land use, explaining 65% of data variability. Spearman correlation analysis illustrated the correlation among nutrient concentrations, land use, and water level changes in SW and SGW environments. This study provides needed baseline data on nutrient dynamics for a riparian wetland in a mixed land-use catchment, supplying science-based information to advance land and water management practices in the study watershed and similar physiographic watersheds globally.

Effects of Acute and Developmental Exposure to Bisphenol S on Chinese Medaka (Oryzias sinensis).

Bisphenol S (BPS), one of the substitutes for bisphenol A (BPA), is widely used in various commodities. The BPS concentrations in surface water have gradually increased in recent years, making it a predominant bisphenol analogue in the aquatic environment and raising concerns about its health and ecological effects on aquatic organisms. For this study, we conducted a 96 h acute toxicity test and a 15-day developmental exposure test to assess the adverse effects of BPS exposure in Chinese medaka (Oryzias sinensis), a new local aquatic animal model. The results indicate that the acute exposure of Chinese medaka embryos to BPS led to relatively low toxicity. However, developmental exposure to BPS was found to cause developmental abnormalities, such as decreased hatching rate and body length, at 15 dpf. A transcriptome analysis showed that exposure to different concentrations of bisphenol S often induced different reactions. In summary, environmental concentrations of BPS can have adverse effects on the hatching and physical development of Chinese medaka, and further attention needs to be paid to the potential toxicity of environmental BPS.

Assessments of heavy metal contaminations of surface water and sediment of Pülümür Stream (Türkiye)

The primary considerations within aquatic ecosystems are water and sediment quality, rendering it imperative to assess their concentrations, pollution levels, origins, and ecological hazards. In this study, heavy metal concentrations in surface waters and sediments of the Pülümür Stream were investigated to assess the level, distribution, source of pollution and the associated human risks. Water and sediment samples from the river were collected monthly from February 2021 to January 2022 and examined using the Inductively Coupled Plasma Mass Spectrometry (ICP– MS) technique. Metal concentrations in the sediment followed a decreasing or derivative sequence of Fe > Al > Mn > Ni > Cr > Zn > Cu > Pb > As >Cd > Hg. The ecological indices of the stream water have low degrees of contamination by heavy metals. Igeo and EF showed that most of the sites are moderately to highly polluted due to Ni, and Cr, while PLI and PERI showed a progressive deterioration of the environment at site 9. Moreover, the modified hazard quotient (mHQ) indicates low ecological risk for Cu, Pb, Zn, Cd, Hg metals, while Ni, As and Cr reach high pollution at sediment sites. Pearson correlation analysis revealed that the presence of Zn, Cu, Pb, Hg, and Mn metals in the sediment analysis has a lithogenic source, and As, Ni, Cd, and Cr accumulate due to human activities, mainly domestic and agricultural irrigation wastes and mining wastes, all of which affect the aquatic environment. According to this study, more attention should be paid to the comprehensive monitoring of metals in the water and sediment for both aquatic biota and human risk of the Pülümür River.

A feasible approach to measure metal concentrations in drill hole waters on site for mineral exploration

The new technologies used in the green transition towards carbon-free societies typically demand extensive use of metals. This leads to a heavily growing need for exploration and extraction of ore deposits. Exploration can be facilitated by measuring metal concentrations in ground and surface waters carrying trace concentrations of metals leached from nearby deposits. Currently, measuring metal concentrations in water is slow and expensive and it cannot be done on-site, which hinders the discovery of new ore deposits. To address this challenge, we have developed a method to collect and concentrate the dissolved metals in a solid filter and measure the metal concentrations directly from the filter with a portable X-ray fluorescence spectrometer. The permeable filter is made of mesoporous silicon modified with bisphosphonates. Two types of adsorbing materials for the filters were prepared based on scalable production methods: i) regenerative etching of metallurgical grade silicon powder, and ii) magnesiothermic reduction of silica from barley husks. Empirical calibrations were prepared in a concentration range of 10–200 μg/L for Mn, Co, Ni, Cu, Zn, and Pb using water samples prepared by spiking well water with standard metal solutions. Both filter types were tested for their ability to adsorb metals from the real water samples taken from drill holes. The developed system was able to detect metal concentrations down to 12 μg/L (ppb) showing its potential for on-site measurements of dissolved metals in water samples, which could be feasible in the discovery of new mineral deposits. This innovation enables smart sampling during exploration and provides real-time information on metal concentrations in water.

Effect of phthalate absorption on the physical properties of ophthalmic hydrogels: A comparative study of ophthalmic hydrogel materials

Ophthalmic hydrogels are known for their hydrophilicity, which although beneficial for eye comfort, also predisposes them to absorbing external compounds, including potentially harmful phthalates. This study investigated the absorption of dimethyl phthalate and diethyl phthalate, plasticizers found in numerous consumer products by ophthalmic hydrogels. The results demonstrate differential absorption capacities between the two hydrogels, attributed to their distinct compositions. The interaction between hydrogels and phthalates is found to be predominantly physical, as evidenced by unchanged chemical structures post-absorption. Notably, phthalate absorption alters surface properties, including surface free energy and water content, while oxygen permeability remains unaffected. These findings underscore the complexity of hydrogel-phthalate interactions and the necessity of accounting for environmental pollutants in the design of ophthalmic materials. This research contributes to the development of safer, more environmentally resilient ophthalmic hydrogels, emphasizing the importance of further studies to mitigate the effects of contaminants like phthalates on contact lenses and other ophthalmic devices.

Determining the likelihood and cost of detecting reductions of nitrate‑nitrogen concentrations in groundwater across New Zealand

Nitrate‑nitrogen (NO3-N) is a contaminant of concern in groundwater worldwide. Stakeholders need information on the ability to detect changes in NO3-N concentrations to prove that land management practices are meeting water quality aims. We created a database of quarterly to monthly NO3-N measurements in 948 sites across New Zealand; 186 of those sites had mean residence time (MRT) data. New Zealand has set a target of sufficient land use mitigations in the next 30 years to ensure steady state surface water concentrations do not exceed 2.4 mg L−1. Here we assess whether the current monitoring network could identify the impacts of these mitigations, assuming that the mitigations are successfully implemented at the source. Only 41 % of the network could detect statistically significant reductions with the current standard quarterly sampling after 30 years of monitoring. The percentage of sites increased to 60 % with increased monitoring frequency (often weekly) but this required a 100–300 % increase in monitoring costs. However, policy makers and stakeholders typically require information on policy and mitigation effectiveness within 5–10 years. Detection within 5–10 years was very unlikely (0–20 % of sites) regardless of the sampling frequency. Importantly, these analyses include the impacts of groundwater lag and temporal dispersion on the likelihood of detecting change, ignoring these impacts, incorrectly, yields a much higher likelihood of detecting reductions. We conclude that the current monitoring network is unlikely to be fit for the purpose of detecting NO3-N reductions within practical timeframes or budgets. Furthermore, we conclude that lag and temporal dispersion effects must be included in detection power calculations; we therefore recommend that MRT data is regularly collected. We also provide a python package to enable easy detection power calculations with lag and temporal dispersion impacts, thereby supporting the development of robust change-detection monitoring networks.

Seasonal variation and spatial distribution of heavy metal (loid)s concentration in groundwater and surface water from hard-rock terrain, Ranchi, India

Seasonal variation and spatial distribution of heavy metal (loid)s concentration in groundwater and surface water from hard-rock terrain, Ranchi, India