Environmental Monitoring and Assessment最新文献

Toxic metals are known pollutants to pose high toxicity to the environment and humans when they occur above threshold levels. In order to meet the requirements of environmental quality standards established by pertinent regulations, analytical processes that perform quick, accurate, and precise determination of such pollutants are becoming more and more important. This study offers a rapid, efficient, and sensitive method for cadmium determination in tap water samples by slotted quartz tube–flame atomic absorption spectrometry (SQT-FAAS). A spray-assisted droplet formation-liquid phase microextraction (SADF-LPME) method was developed to simultaneously extract and preconcentrate cadmium ions using microliter volumes of solvent in agreement with green analytical chemistry. Hydrazone type complexing ligand and diphenylcarbazone were tried to check the complex formation efficiencies. The optimum extraction conditions were determined by comprehensive examination of the parameters affecting complexation and extraction. The limit of detection/limit of quantification values for the DPC and L-4 hydrazone ligands under optimum conditions were 0.70/2.4 µg/L and 1.1/3.5 µg/L, respectively. The linear dynamic range for cadmium was found to be 2.0–75 µg/L, and the correlation coefficient (R²) was higher than 0.99. The method has been successfully applied to tap water samples, with recovery results close to 100% validating the accuracy of the method.

Microplastic pollution is an emerging threat to freshwater ecosystems, yet remains insufficiently monitored in regions where water quality assessment still depends largely on conventional physicochemical parameters. This study investigates microplastic contamination in a freshwater ecosystem in Kallakurichi, Tamil Nadu, and its sub-lethal effects on the sentinel fish Puntius sophore. Surface water and fish specimens were collected from multiple sampling stations and examined for microplastic presence using Fourier Transform Infrared Spectroscopy (FTIR), followed by histopathological evaluation of intestinal, hepatic, and renal tissues and haematological assessment. Although physicochemical parameters were within permissible limits, FTIR confirmed the presence of polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET), predominantly in the form of fibres. Histopathological alterations, including epithelial lifting, vacuolization, necrosis, and inflammatory infiltration, showed a dose-dependent pattern of tissue damage. Haematological changes further indicated stress-related physiological responses. These findings demonstrate that P. sophore functions as a sensitive bioindicator for microplastic exposure and highlight a critical gap in current water quality monitoring frameworks, which fail to detect emerging micropollutants. The study underscores the urgent need to include microplastic indices in freshwater monitoring programs to safeguard aquatic biodiversity and public health.

Non-point source pollution from stormwater runoff has become one of the main contributors to pollution in urban water bodies. In this study, we aimed to quantify changes in limnological variables (including nutrients), pollutants (heavy metals, microplastics, hydrocarbons), and microbial communities (coliform bacteria and phytoplankton), with particular emphasis on precipitation events in an urban drainage reservoir. To achieve this, we sampled three urban runoff channels that drain water from two main areas of Santa Fe City (Argentina) over an entire hydrological year, including four rainfall events. The results revealed differences among the drainage channels, with hydrocarbons and nitrogen contamination predominating in channel 1, organic matter in channel 2, and eutrophic conditions in channel 3. In all cases, coliforms bacteria and Escherichia coli levels exceeded permitted limits for most of the year, and phytoplankton communities were dominated by species indicative of organic matter pollution and eutrophication. Precipitation events only significantly affected dissolved inorganic nitrogen forms (positive correlation) and hydrocarbons (negative correlation). These findings highlight the importance of integrated stormwater management to reduce pollutant loads, with different management strategies tailored to each runoff channel and urban area.

The Dongting Lake Basin (DLB) is integral to ensuring ecological security in the middle reaches of the Yangtze River. Alterations in land use and the degradation of ecological functions present significant challenges to the region’s sustainable development. However, existing research has either focused on ecologically fragile upland watersheds such as the Loess Plateau or on highly urbanized regions such as the Yangtze River Delta, leaving a knowledge gap concerning composite basins like the DLB where ecological, agricultural, and urban functions interact dynamically. This study, focusing on the DLB, evaluates ecosystem service functions utilizing the InVEST model. Circuit theory is employed to identify ecological source areas, pinch points, corridors, and barrier points, thereby facilitating the construction of an ecological security pattern. The findings of the study are as follows: (1) Between 2000 and 2020, land use changes in the DLB followed a pattern of two decreases and two increases. (2) During the same period, the water conservation and soil retention functions of the DLB initially declined and subsequently recovered, while carbon sequestration functions were concentrated in the lake area. Urban expansion resulted in localized habitat degradation. (3) The ecological source areas of the DLB in 2000, 2010, and 2020 were identified as 18,925.38 km², 14,770.23 km², and 30,941.38 km², respectively. Ecological corridors numbered 97, 193, and 191; ecological barriers numbered 37, 54, and 45; and ecological bottlenecks numbered 75, 71, and 33. (4) An ecological security pattern was established, characterized by a one core, three zones, three corridors, two axes, and multiple nodes framework. This structure is defined by a central ecological core anchored by DLB, three differentiated management zones for conservation, restoration, and control, three primary ecological corridors to ensure connectivity, two axes delineating urbanization pressures, and multiple critical ecological nodes requiring targeted action. By explicitly linking ecosystem service assessment with circuit-theory-based connectivity analysis, this study advances current ESP research by addressing multi-scale land use conflicts in a composite ecological-agricultural-urban watershed. The results not only demonstrate the remarkable recovery of ecological source areas under national restoration policies, but also provide a novel framework for coupling ecosystem service dynamics with ecological security pattern construction. Thus, this work fills an important knowledge gap and offers a transferable reference for building ecological security in other large river basins.

River systems often retain the imprint of historical mercury (Hg) contamination over long time scales since decreasing trends after reduced Hg inputs are impeded by legacy storage in sediments. Here, we report temporal and spatial variations of total mercury (THg) concentrations in sediments of the Elbe River, Germany. Temporal THg trends (1996–2019) were investigated at five long-term monitoring sites in harbors and groyne fields. In contrast to well-documented declines of THg in suspended particulate matter (SPM) in recent decades, significant trends of decreasing THg in sediments were only found for two harbors, while the other sites exhibited no decreasing trends. Spatial distribution patterns of THg in sediments (0.11–10.6 mg kg⁻¹) showed increases in areas of the Middle Elbe downstream of the confluences of the tributary rivers Mulde and Saale. Similar spatial patterns of increasing concentrations were observed in floodplain soils (0.04–4.20 mg kg⁻¹) and SPM (0.37–1.84 mg kg⁻¹). Regardless of the spatial origin or sample type (sediments, floodplain soils, SPM), the binding forms of Hg studied by sequential extraction showed a clear dominance of strongly bound Hg extractable with 12 M HNO₃. While this seems to indicate a low mobility of Hg, uptake into aquatic food webs may occur following methylation. Our results demonstrate that the reduction of Hg releases into the Elbe River basin has so far only been able to improve sediment quality in some parts. Deposits of Hg-containing sediments will therefore remain a future problem with implications for the continued exceedance of environmental quality standards and the management of waterways.

Population growth and agricultural expansion cause major changes in land use and land cover (LULC) in Ethiopia. Cultivated lands are mostly expanding without land suitability evaluation. Consequently, crop yields are not increasing as expected. This is particularly the case in the highland catchments draining toward Lake Tana, where severe consequences such as deforestation and the degradation of soil and land can be observed. In this study, the impacts of long-term LULC dynamics on the land suitability potential for selected major crops in three sub-catchments of Lake Tana, Ethiopia (Gilgelabay, Gumara and Ribb), were evaluated. Time series of Landsat images from three periods (1988, 1998, and 2017) were classified. Land suitability was analyzed via a multi criteria approach based on spatial input data such as elevation, soil, and slope maps. The overall accuracy for all LULC classifications was good to very good (89.7% to 91.6%). Five major LULC classes were distinguished: agriculture, forest, shrub/bushland, grassland, and water. In all three catchments, the results revealed that agricultural land was the dominant land cover that expanded at the expense of the other land cover types to 80%-90% in all catchments in 2017. The rate of change in agricultural land in the Gilgelabay catchment (4041.3 ha/yr) was greater than that in the Gumara (1374.5 ha/yr) and Ribb (1362.3 ha/yr) catchments. This is possibly due to the availability of other LULC classes. The natural vegetation of Gilgelabay, Gumara, and Ribb has decreased by 16.0%, 10.5%, and 1.1%, respectively, over the past three decades. However, the present LULC change trends are unsustainable, and any remaining natural vegetation should be maintained. The results from the land suitability analysis revealed that the land suitability for teff, corn, and rice is likely to change with climate change in the future. To ensure sustainable land use management, modifying land use on the basis of land suitability should be preferred over traditional practices to improve crop production. This can be achieved in close collaboration with all stakeholders, including local communities, the government, and NGOs.

The principal impacts of road infrastructure on wildlife include biodiversity loss, habitat fragmentation, increased human presence, and the creation of barriers or boundaries. These effects can have significant repercussions, particularly for amphibians and reptiles. In tropical ecosystems, information on the impacts of roads within Protected Natural Areas (PNA) is limited. Therefore, this research seeks to identify hotspot areas exhibiting high mortality rates among herpetofauna within and outside the Selva El Ocote Biosphere Reserve, Chiapas, Mexico. Given the biological characteristics of herpetofauna, particularly their ectothermic nature, coupled with the relatively more pristine vegetation within the PNA, it is anticipated that the most significant incidence of roadkill will occur within the PNA limits. In this regard, 20 road surveys were conducted along 5-km transects on two highway corridors from July 2019 to March 2020. A total of 140 instances of road mortality among herpetofauna were documented, comprising 52 amphibians and 88 reptiles. The kilometric index for global roadkill abundance was calculated to be 0.28 roadkilled individuals per kilometer. Furthermore, six roadkill hotspots were identified within the Selva El Ocote Biosphere Reserve, three outside the reserve boundaries. The critical regions identified in this study encompass a variety of endangered (5) and native species (2). These locations, which exhibit elevated mortality rates among herpetofauna, will serve as the basis for developing strategies to mitigate the impact of roadways on these taxa within Selva El Ocote.

Bisphenol analogues (BPs) are increasingly detected in various environmental media and have uncertain ecological outcomes. Despite growing industrial use, comprehensive assessment data on their distribution and behavior remain limited. This study involves assessing the concentrations of several BPs (BPB, BPE, BPF, and BPAF) in the Sitalakhya River, revealing seasonal trends and their distribution patterns. A total of 90 samples (60 water, 30 sediment) were collected during the rainy and winter seasons. Gas Chromatography-Mass Spectrometry (GC–MS) technique was used to determine the presence and concentration variation of these emerging BP analogues. In the rainy-season water samples, BPF was dominant, ranging from (0.94–5.37) μg/L, followed by BPAF (0.32–1.64) μg/L, BPE (0.46–1.49 μg/L, and BPB (0.12–2.36) μg/L, respectively. Samples obtained from water sources in winter also contained BPF as the most abundant (1.98–7.46) μg/L. In the sediment sample, the leading BP was BPAF, ranging from (64.14–224.40) μg/g dw, followed by BPB (22.07–135.16), BPF (9.52–150.62), and BPE (10.42–120.55) μg/g dw, respectively. Water samples showed strong positive correlations among BPs, while sediment samples lacked significant associations. The study provides a comprehensive insight into the presence of these emerging contaminants in the urban river system of Dhaka, highlighting the need for regular monitoring.

Pesticide use in intensive agricultural systems poses a growing concern for human and environmental health. In Costa Rica, large-scale pineapple cultivation involves frequent agrochemical applications, increasing the potential for contamination of groundwater and agricultural products. This study evaluated human health risks associated with pesticide residues detected in groundwater and pineapples from the Northern Region of Costa Rica, where intensive pineapple production takes place. Concentration data from ten groundwater sources and 30 pineapple samples collected between 2015 and 2018 were analyzed. Non-carcinogenic risk (estimated as a hazard quotient, HQ) and carcinogenic risk were determined for adults and children using U.S. EPA reference doses and cancer slope factors. Nine pesticides were detected in groundwater and nine in pineapples, with bromacil (up to 3.8 μg/L) being the most frequent compound in water and carbendazim (up to 0.027 mg/kg) in the fruit. All hazard quotients (HQ < 1) indicated no non-carcinogenic risk for either exposure route. Carcinogenic risks were only assessed for imazalil and diuron, with values for imazalil in groundwater ranging from 2.4 × 10⁻⁷ to 3.3 × 10⁻⁶, slightly exceeding the reference threshold (1 × 10⁻⁶) in children. Risk values from pineapple consumption were lower (≤ 10⁻⁷) compared to those from groundwater intake, suggesting minimal concern. Although overall risks remain low, the detection of residues in both water and fruit reveals multiple exposure pathways and highlights the need for cumulative risk assessments. Strengthening environmental monitoring and promoting integrated pesticide management are essential to safeguard public health in regions under intensive agricultural production.