Zone Of Contamination Research Articles

Assessment of land use and monsoon impact on high nitrate groundwater and health risk in the hard rock aquifer, South India.

Groundwater sustainability in hard rock aquifers is compromised largely due to nitrate contamination from anthropogenic sources resulting in diminishing potable resources and attendant health issues. A purpose-driven study through an integrated approach was undertaken in the area of interest (hard rock aquifer) to assess the variations in nitrate concentration and resultant health impacts in response to variations in monsoon and land use patterns. Groundwater samples (n = 284) were collected for a period of three years (2017-2019) and analysed. From the analytical data, it is inferred that 27% and 9% of groundwater samples in the study area have high NO3- values of > 45mg/l and > 100mg/l, respectively. NO3- contamination zones mapping illustrates that NO3-contaminated area (> 45mg/l) varied seasonally 1164 km2 (2017), 1086 km2 (2018) and 1640 km2 (2019)) and high-risk area (NO3- > 100mg/l) has reduced drastically during 2018 due to dilution by monsoon (277 km2 (2017), 41 km2 (2018), 634 km2 (2019)). The lowest NO3- and Cl-concentrations are recorded during 2018 which coincides with high rainfall (2061mm). NO3- concentrations in response to land use pattern indicate that the hot spots (NO3- > 45mg/l and > 100mg/l) are observed in groundwater samples of residential areas which are vulnerable to contamination from domestic wastewater, septic tanks and other pollutants. Further, wastewater infiltration facilitated the dissolution of certain minerals in the unsaturated zone which enhanced the accumulation of NO3- and other ions in this aquifer. Mineral weathering, denitrification and evaporation processes also affected the groundwater chemistry. The health risk model (HQoral) indicates that groundwater in 1261 km2 (2017), 1232 km2 (2018) and 1669 km2 (2019) is unsuitable for drinking (HQ > 1) and causes adverse health risks to the local inhabitants. The study has identified areas from the central and southeastern regions significantly affected by nitrate pollution underpinning the necessity of using treated groundwater for drinking purposes.

Bioremoval of copper by filamentous fungi isolated from contaminated soils of Puchuncaví-Ventanas Central Chile.

Pollution represents a high risk to plants, animals, and human beings, causing an imbalance and affecting the environment. Soil is considered a universal sink, containing the highest load of environmental pollution. Puchuncaví-Ventanas sector, decreed as a saturated contamination zone in 1993, is considered one of the most affected areas by industrial pollution and belongs to one of the 5 sacrifice zones of Chile. The localities of Puchuncaví and Ventanas have heavy metal pollution levels that exceed up to 99% of the limits allowed by Canadian standards. The objective of this study was to characterize heavy metal tolerance and removal potential of filamentous fungi isolated from polluted soils for their use in decontamination systems and in situ soil improvement. Six fungal strains were selected based on their tolerance and a high capability to accumulate heavy metals, achieving copper bioaccumulation of 84% (Mortierella sp. strain LG01), 49% (Clonostachys sp. strain CQ23) and 48-77.5% (Trichoderma sp. strain LM01A). Trichoderma sp. strain LM01A was able to remove 41% of copper from contaminated soil under ex situ conditions. Some fungal strains belong to beneficial fungal genera, which are used as bioproducts in agriculture. The results of this study highlighted the use of Trichoderma sp. in soils contaminated, which may be of special interest in agriculture due to the large amounts of copper sulfate still applied as a pesticide in Chile and the world.

Electrokinetically-delivered persulfate and pulsed direct current electric field induced transport, mixing and thermally activated in situ for remediation of PAHs contaminated soil.

Herein, we proposed and proved a novel strategy that enhanced the delivery of persulfate (PS) to soil by electrokinetics (EK), and then applying a pulsed direct current (DC) electric field thermally activated the PS in situ, and synchronously promoted PS plume mixing, contaminants-free radicals reaction and continued to replenish PS to the soil, to achieve efficient degradation of contaminants in low permeability zones. Results showed that transport rate of PS in tested soil by EK was approximately 12.3 times than diffusion. Applying an irregular pulsed DC field maintained the targeted temperature (30-50℃) during activation phase, and generated two oxidative radicals (SO4∙-/∙OH). Concurrently, in the case, electromigration and electroosmosis have promoted the PS transport and the reactive mixing of PS/free radicals with polycyclic aromatic hydrocarbons (PAHs) contaminated soil and enhance the PAHs degradation. PS concentrations in pore fluid was characterized by an increase accompanied by continuous fluctuations. Eventually, in case of the long-term low-temperature activation (i.e., 30-40 ℃), a significant decreases (nearly 60%) in average concentration of PAHs in the whole soil cell was observed over 10 days. These results demonstrates that the novel strategy has great potentiality in the remediation of low permeability contaminated soil.

2D Resistivity Technique in Exploring Soil Contamination Zones, Kwashe Area, Duhok, North of Iraq

The impacts of leachate on the soil count as one of the main environmental issues, especially near waste dump areas. The Kwashe dumpsite is located in the Semel district, west of Duhok City. Different types of waste had accumulated from medical, construction, and household materials without any barrier or control of the contamination. Wastewater flows on the surface and percolates downward all over the area. Geophysical methods provide high-resolution data to investigate subsurface environmental conditions with no disturbance in the materials. In this study, the 2D resistivity technique by Ohm-Mapper device (G-858G) with a dipole-dipole arrangement was utilized along six resistivity profiles. the system uses one Transmitter to couple an active current signal to the ground and the voltage difference is recorded by one Receiver with separation distances of 2.5, 5.0, 10.0, and 15.0 m. The resistivity data from MagMapper software was transferred to Res2dinvx32 software to create an inversion model for the subsurface. The results showed two main parts: The upper part consists of soil material mixed with recent deposits and fill materials formed of alluvium deposits with resistivity values of 15-50 Ohm.m at a depth between 0.25-3.0 m. The bottom section represents leachate of bowl-shaped anomalies of very low resistivity values of less than 1.0 Ohm.m at various depths. The type of materials in the left and right edges of each of the models represent the main weak zone for leachate infiltration.

Management proposal of a naturally occurring wetland modeled as a constructed wetland

Environmental management and restoration aim to accelerate the recovery of ecosystems that have been affected by human activities. This paper presents the diagnosis and management proposal for the Valsequillo wetland, Puebla, Mexico. The study site is a natural wetland dominated by water hyacinth (Eichhornia crassipes) which performs a biofiltration process by reducing the pollutant load of the water. To increase the efficiency of the wetland, an annual harvest plan is proposed in this work. However, the ideal amount of biomass to harvest is unknown. In order determine the optimal annual harvest plan, this natural wetland was modeled as if it were a surface flow wetland by using the equations described. A total of 48 surface water samples were collected in three different seasons of the year (dry, rainy, and winter) and 34 water quality physicochemical parameters were measured. Additionally, two water quality indices were determined, namely: Overall Index Pollution (OIP) and Heavy Metal Evaluation Index (HEI) to determine the degree of contamination in different zones of the study area. The model results showed that in order to achieve the desired removal of total phosphorus (TP) or chemical oxygen demand (COD), 274 ha or 306 ha of aquatic plants must be harvested, respectively. The results of the modeling showed that this action will optimize the function of the wetland by improving the removal of total suspended solids (TSS, 6%), total nitrogen (TN, 24%) TP (31%), chemical oxygen demand (COD, 11%) and biochemical oxygen demand (BOD5, 101%).

Emergency unmanned airborne spectrometric (HPGe) monitoring system

After a nuclear or radiation event, emergency responders and radiation protection authorities need quick and credible information based on reliable accident and post-accident radiological data. However, risks to people in the vicinity of the source pose serious measurement challenges. Many problems could be solved by unmanned airborne monitoring systems, but the current ones are mostly based on non-spectrometric detectors carried by drones with low bearing, short flying range and flight time. Therefore spectrometric monitoring system based on High-Purity Germanium (HPGe) detector carried by powerful unmanned helicopter has been developed. The presented unmanned aerial spectrometric system is reliable and heavy-duty and enables quick and safe identification of released radionuclides, thus provides a basis for determining the plant damage state and for planning of emergency and contamination zones. The system will support timely, effective actions that protect the public and environment against the effects of ionizing radiation. The paper describes development and performance tests of this novel system.

A Systematic Approach to the Development of a Methodology for Comparative Analysis of Scenarios for the Shelter Object Transformation into an Ecologically Safe System

A comprehensive assessment of the impact of wildfires in the Chornobyl Exclusion Zone on the adjacent territory within a radius of 100 km in the spring of 2020 and 2022 was carried out, considering the potential and realized radioecological criticality of the territory. The realized radioecological criticality was expressed in the estimated specific activity of 137Cs in plants, which was formed as a result of aerial and root pollution of agricultural vegetation in farm fields and gardens during the transfer and deposition of radionuclides during fires. The specific activity of 137Cs in plants was calculated based on the data on the integrated volumetric activity of 137Cs, obtained by the WRF-LEDI model of atmospheric transport, using the set of models “AeralPlant — SoilPlant” depending on the biological stage of plant development. According to the results of the calculations, thematic mapping was carried out with the selection of zones of maximum and minimum contamination of the territory, taking into account potential radioecological criticality. Regardless of the volume activity of 137Cs in the air and the direction of air transfer, the spatial nature of the distribution of the most critical areas is preserved. As a result, the most critical areas were identified, where dangerous levels of radiation exposure on the population are possible due to atmospheric transport of radionuclides caused by wildfires and extreme weather phenomena (dust storms) in the Chornobyl Exclusion Zone. Different scenarios of the regional land use structure were considered and thematic assessment maps were built, which are the basis of preventive planning of rehabilitation measures in case of critical situations in accordance with radiation safety norms.

Оценка мощности амбиентного эквивалента дозы на лесных участках в юго-западных районах Брянской области

The large areas of forests in the Bryansk region are still contaminated with radionuclides released due to the accident at the Chernobyl NPP in April, 1986. The recovery of the economic and ecosystems potentials in the contaminated areas is the need to create a favorable living conditions for the population. This involves a full range of remediation activities in the contaminated areas aimed at the forests protection and regeneration. The aim of the work is to assess the ambient dose equivalent rate (ADER) in forest sites located in the zone of radioactive contamination. More than 1 thousand forest sites in the south-western part of the Bryansk region were surveyed from 2019 to 2022. The ADER and the density of the soil contaminated by Cs-137 for every surveyed forest site are available. The relationship between the ADER and the density of the soil radioactive contamination in various sites was analyzed. The dose rates were normalized with respect to the density of soil contamination. The ADER rates in the Bryansk forest areas ranged from 0.07 to 3.15 mSv/h. No reliable difference between the ADER in the areas of coniferous and deciduous forests was observed. There was reliable linear relationship between ADER and the density of soil contaminated by Cs-137. During forestry operations in radioactive contaminated areas the maximum permissible external radiation effective dose was the dose accumulated for the whole period of work in the forest sites with the average density of soil contaminated by Cs-137 of 450 kBq/m2.

ACCUMULATION OF 137Cs, Pb, Cd, Сu IN THE MUSCLE TISSUE AND LIVER OF PIGS GETTING DIFFERENT RATIONS

Experimental studies on young pigs of the large white breed were conducted on the territory of the physiological yard of the Polissia Institute of Agriculture of the National Academy of Sciences (III zone of radioactive contamination due to the accident at the Chernobyl Nuclear Power Plant). To conduct the experiment, 2 groups of experimental animals were formed: Group I (control) was fed with grain mixture № 1 with narrow-leaved lupine (alkaloid-free) and sunflower cake; II group (experimental) received grain mixture № 2 with genetically modified soy. Experimental pigs were kept in one room according to the accepted technology in group cages equipped with a wooden floor. The mode of feeding and drinking, parameters of the microclimate in both groups were the same. According to the results of tests conducted at the Ukrainian Laboratory of Quality and Safety of Agricultural Products, it was established that soybeans contain genetically modified deoxyribonucleic acid (DNA), have the target sequence of the 35S+FMV promoter of the cauliflower mosaic virus and the NOS terminator (nopaline synthase) of Agrobacterium tumefaciens. The specific activity of 137Cs in the longest back muscle of pigs varied by group within 3.7-10.3 Bq/kg and did not exceed permissible levels (DR-2006 = 200 Bq/kg). When used as part of the GM soybean grain mixture, the concentration of radiocesium in the muscle tissue of animals of the II (experimental) group relative to the control decreased by 6.6 Bq/kg, or by 64.1% with a statistically significant difference (Р> 0.95). Moreover, the accumulation rate of 137Cs in the longest back muscle of piglets was 0.46-0.95 and was 2.1 times higher in young pigs that received grain mixture No. 1 without GM soybeans, compared to the use of grain mixture No. 2. The concentration of Pb in the slaughter products of experimental animals was significantly lower than the MPC, while the level of contamination of the longest back muscle of pigs Cd exceeded the regulatory requirements by 1.40-1.44 times. The introduction of 60% (by mass) of corn gain and 10% of GM soybeans into the grain mixture instead of the same amount of wheat grain, lupine and sunflower cake for fattening young pigs in the III zone of radioactive pollution contributes to a smaller accumulation of heavy metals in meat: Pb – by 17.5%, Cd – by 2.8%, Cu – by 4.2%. Therefore, the transition coefficients of Pb and Cd into the muscle tissue of animals of the II (experimental) group relative to the analogues of the I (control) group increased by 1.24% and 3.02% respectively, and Cu decreased by 0.23%.

Assessment of Bacteria Contaminants in Different Zones and Point Sources of Sandy Beaches in Accra, Ghana.

Bacteria are ubiquitous in the marine environment. Increasing concern for human health has led to growing interest in contamination on public beaches. The presence of pathogenic microorganisms originating from anthropogenic activities such as defecation and disposal of sewage on beaches are of special concern. In this study, presence of pathogenic bacteria and bacterial load in beach zones and point sources were investigated. Sand core samples from the subtidal zone, intertidal zone, supratidal zone and point sources from 5 beaches in Accra, Ghana, were collected and analysed. Total aerobic, coliform and Escherichia (E. coli) counts were determined for each zone in the respective beaches. Bacteria isolates were presumptively identified using biochemical tests and confirmed with MALDI-TOF MS. Mean total aerobic count and total coliform counts ranged from 2.10 to 3.01 log CFU/g and 0.29 to 2.18 log CFU/g respectively while E. coli counts ranged from 0.12 to 1.71 log CFU/g for the beaches. Total aerobic count from point sources was 2.4-folds higher than the subtidal zone while total coliform counts were 5-folds higher in the point sources compared to the supratidal zone. Point sources had 10 times (P = .0016) more E. coli counts as compared to the subtidal zone. Isolates recovered (n = 35) belonged to 10 bacteria genera. These were Bacillus spp. (25.7%), Acinetobacter spp. (14.3%), Aeromonas spp. (14.3%), Klebsiella pneumoniae (14.3%), Aerococcus viridans (8.6%), Staphylococcus spp. (8.6%), Shewanella profunda (5.7%), Rheinheimera soli (2.9%), Pseudomonas aeruginosa (2.9%), and Exiguobacterium aurantiacum (2.9%). Point sources are major contributors to contamination on beaches. The presence of potentially pathogenic bacteria in beach sand could be a public health risk. Sensitization on cleanliness in the marine environment including beaches in Ghana is needed to enhance public health and safety.

Spatial Heterogeneity and Temporal Stability of Baseflow Stream Chemistry in an Urban Watershed

AbstractSynoptic sampling of streams is an inexpensive way to gain insight into the spatial distribution of dissolved constituents in the subsurface critical zone. Few spatial synoptics have focused on urban watersheds although this approach is useful in urban areas where monitoring wells are uncommon. Baseflow stream sampling was used to quantify spatial variability of water chemistry in a highly developed Piedmont watershed in suburban Baltimore, MD having no permitted point discharges. Six synoptic surveys were conducted from 2014 to 2016 after an average of 10 days of no rain, when stream discharge was composed of baseflow from groundwater. Samples collected every 50 m over 5 km were analyzed for nitrate, sulfate, chloride, fluoride, and water stable isotopes. Longitudinal spatial patterns differed across constituents for each survey, but the pattern for each constituent varied little across synoptics. Results suggest a spatially heterogeneous, three‐dimensional pattern of localized groundwater contaminant zones steadily contributing solutes to the stream network, where high concentrations result from current and legacy land use practices. By contrast, observations from 35 point piezometers indicate that sparse groundwater measurements are not a good predictor of baseflow stream chemistry in this geologic setting. Cross‐covariance analysis of stream solute concentrations with groundwater model/backward particle tracking results suggest that spatial changes in base‐flow solute concentrations are associated with urban features such as impervious surface area, fill, and leaking potable water and sanitary sewer pipes. Predicted subsurface residence times suggest that legacy solute sources drive baseflow stream chemistry in the urban critical zone.

Дозы облучения населения Беларуси вследствие аварии на Чернобыльской атомной электростанции на 2021-2025 гг.

In accordance with the Laws of the Republic of Belarus «On the social protection of citizens affected by the accident at the Chernobyl NPP» dated January 6, 2009 and «On the legal regime of territories exposed to radioactive contamination due to the accident at the Chernobyl NPP» dated May 26, 2012, the value of the average annual effective dose of exposure to residents is one of the indicators of the radiation situation in settlements contaminated with radionuclides as a result of the Chernobyl accident. The objective: to update the method for assessing the exposure doses to the population in the situation of existing exposure after the Chernobyl accident and, on its basis, to assess the average annual effective exposure dose to residents of settlements of the Republic of Belarus due to the Chernobyl accident for the period 2021-2025. The method for estimating the average annual effective doses due to external and internal irradiation to residents of radioactively contaminated settlements of the Republic of Belarus has been improved taking into account international recommendations in the field of radiation protection, changes in the radiation situation in the long-time period after the Chernobyl accident and the new data on individual dosimetry of internal exposure to the population based on the results of whole-body counter (WBC) measurements. An assessment of the average annual effective exposure doses to the population of the Republic of Belarus residing in the territory of radioactive contamination was carried out, and based on its results, the Catalog of average annual effective exposure doses to residents of 2193 settlements for the period 2021-2025 was compiled. According to the compiled Catalog of average annual effective exposure doses to residents of settlements located on the territory of radioactive contamination of the Republic of Belarus, in 29 settlements out of 2193, the total effective exposure dose can exceed 1 mSv/year, in addition, it is about 1 mSv/year in 5 settlements. In none of the settlements, the average annual effective radiation dose can exceed 5 mSv/year. Valid for the period 2021-2025 Catalog of average annual effective exposure doses to the residents of settlements located on the territory of radioactive contamination of the Republic of Belarus, along with data on the density of contamination of the territories of the Republic of Belarus with long-lived radionuclides, was used to compile the List of settlements and objects located in the zones of radioactive contamination, and to adopt a Resolution of the Council of Ministers of the Republic Belarus on designation of settlements to the corresponding zones of radioactive contamination.

The concentration of heavy metals in the energy crops phytomass when grown in the conditions of Zhytomyr Polissia

The high level of anthropogenic pressure on agro-landscapes recently leads to an increased level of their contamination with heavy metals, which are among the most harmful chemical pollutants for the environment. Heavy metals are transmitted through trophic chains with a pronounced cumulative effect, in connection with which their toxicity can appear suddenly on individual links of trophic chains. The danger from heavy metals is determined by the fact that, unlike organic pollutants, they do not break down, but change from one form to another. Based on the results of the study, it was established that the accumulation of heavy metals by energy plants depended on the type of crop. Thus, it was proved that the concentration of heavy metals in energy crops plants when grown in the territory of radioactive contamination was within the limit of permissible concentrations. The lowest concentration of toxicants was noted when all energy crops were grown without fertilizers. The subject of the study was energy crops (Silhium perfoliatum L., Sorghum almum Parodi, Bunias orientalis L., Sida hermaphrodita Rusby, Miscanthus giganteus G.), heavy metals in plants, sod-podzolic sandy soil, mineral fertilizers. Therefore, the purpose of our research was to determine the phytomass of energy crops grown in areas contaminated with radionuclides as a result of the accident at the Chernobyl Nuclear Power Plant to determine the concentration of toxic substances. When performing the work, both general and special research methods were used: field – for conducting stationary and short-term field experiments, analytical – for determining the content of heavy metals in plants crops (Silhium perfoliatum L., Sorghum almum Parodi, Bunias orientalis L., Sida hermaphrodita Rusby, Miscanthus giganteus G.). The research was conducted during 2017−2020 on sod-podzolic soils in the territory of the village. Khrystynivka, Zhytomyr region, which belongs to the zone of unconditional (mandatory) resettlement (2nd zone of radioactive contamination). Prospects for further research will be aimed at establishing patterns of distribution of heavy metals in soil layers when growing energy crops. Key words: Silhium perfoliatum L., Sorghum almum Parodi, Bunias orientalis L., Sida hermaphrodita Rusby, Miscanthus giganteus G., lead, cadmium, copper, zinc.

Peculiarities of the woodworking industry development in Ukraine and its regions

The article reveals the woodworking industry as a component of the wood processing complex and a perspective export-oriented sector of the Ukrainian economy. The purpose of the research is to identify the main trends and results of the development of the woodworking industry in the Ukraine regions in the pre-war period, to identify problems and to substantiate possible ways of solving them in the post-war period. The role and importance of the woodworking industry in the formation of the country's GDP was studied. The prerequisites for the formation and formation of the woodworking industry in Ukraine are characterized, namely, the level of forest cover in the country is analyzed, which directly affects the provision of raw materials for enterprises in the industry. Regional differences in natural conditions are determined, which is the reason for significant interregional differentiation of the development of the woodworking sector. The amount of produced forest products in the regions of Ukraine in the pre-war period was analyzed. It has been proven that the lack of raw materials remains a problem for the woodworking industry. It has been established that the forestry of Ukraine is characterized by a relatively low level of forest cover in the country, significant regional differentiation of forests, and a high proportion of ecologically significant forests; individual forests are provided for permanent use by enterprises; a significant area of forests grows in the zone of radioactive contamination; half of Ukraine's forests are artificially created and require increased care. It has been found that there is a dynamic and constantly growing demand for woodworking products. This attracts capital to the industry, increasing competition, which was quite high in the market for wood and wood products in Ukraine before the war. The woodworking industry market of Ukraine meets the conditions of effective competition, where small enterprises prevail. It was established that about 40% of the products of the woodworking industry are sold abroad. The most promising areas of industry are the manufacture of wood products, its processing and furniture production. Sawmill and planing production are the most export-oriented. At the same time, it was found that Ukraine will continue to be an exporter of mainly raw materials and products with a low share of added value. This reduces the efficiency of export activities and additionally creates pressure on the development of enterprises with a complex production cycle, increasing the shortage of wood raw materials. The article describes the current state and problems of the development of the woodworking industry during the war. The main directions of restoration of the woodworking sector of Ukraine in the post-war period are outlined.

Mass transfer enhancement of air sparging on VOCs contaminated low-permeability soil by establishing pressure gradient

As one of the most effective methods for remediating VOCs contaminated site, air sparging technology is not suitable to low-permeability soil due to the poor remediation efficiency. To solve this problem, an improved approach aiming for mass transfer enhancement by establishing pressure gradient in soil is proposed in this study, and the remediation efficiency, removal mechanism, as well as the mass transfer characteristic are comprehensively investigated. Test results showed that, using the proposed approach significantly reduced the time for exhaust air contaminants reaching concentration equilibrium, and improved the contaminant removal zone and extent in soil, which were especially strengthened at sparging pressures higher than 40 kPa. The total contaminant removal rate was improved by introducing the proposed approach, with a maximum improved removal rate of 23.7% at 100 kPa sparging pressure. In mechanism analysis, the recorded changes in total pore pressure and average liquid saturation illustrated the pressure drop and discrete drainage phenomena, confirming the pressure gradient and air sub-channels formed in low-permeability soil. Finally, contaminant mass transfer characteristic was quantitatively analyzed using the lumped parameter model, in which the mass transfer coefficient and the air channel influencing fraction were enhanced almost fourfold and fivefold respectively by introducing the proposed approach. Compared to the conventional approach, the improved remediation efficiency using the proposed approach tackled the in-situ remediation challenge on low-permeability soil, and further expanded the application scope of air sparging technology on VOC contaminated site.

Spatial Distribution, Ecological Risk Assessment and Source Analysis of Heavy Metals Pollution in Urban Lake Sediments of Huaihe River Basin.

Heavy metals in freshwater lake sediments often exist in various chemical forms. However, the investigation and evaluation of heavy-metal elements in the sediments of the study area have not been reported, and there is a lack of objective understanding of the concentration level of heavy-metal elements. Therefore, this study is the first to report the concentrations, sources, and potential ecological risks of heavy metals in the sediments of Chengdong Lake and Chengxi Lake in Huoqiu County, Anhui Province, China. The spatial distribution, pollution characteristics, potential pollution sources, and ecological risks of heavy metals in the sediments of Chengxi Lake and Chengdong Lake of Huoqiu City in the middle section of Huaihe River in Anhui Province, China have not been reported. In this study, the sediment samples of the two Lakes were collected systematically, and the concentrations of heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) were determined. The potential sources of heavy-metal elements in sediments were quantitatively analyzed according to the principal component analysis-absolute principal component fraction-multiple linear regression (PCA-APCS-MLR) receptor model. Descriptive statistics data showed that the enrichment degree of heavy metals in Chengxi Lake was higher than that in Chengdong Lake. The geo-accumulation index (Igeo) and pollution load index (PLI) indicated that there was moderate pollution for Cu, As, Hg, Ni, and Zn. The calculation results of the potential ecological risk index (Er) of the two lakes indicated that Cd (Er,max = 92.22, n = 60) and Hg (Er,max = 64.39, n = 60) showed a certain potential ecological risk in a small amount of sediment, while other heavy metals were classified as low risk. The mean sediment quality guideline quotient indicated that there was a moderate degree of potential adverse biological toxicity in lake sediments. Spatially, the seriously polluted contamination zones were the central position of Chengxi Lake and the northeast end of Chengdong Lake. The PCA-APCS-MLR receptor model revealed that Cr, Ni, Cu, and Zn were mainly from natural sources while Cd, As, Hg, and Pb elements were mainly from industrial sources and pesticide sources.

Differentiation between Impacted and Unimpacted Microbial Communities of a Nitrogen Contaminated Aquifer

Nitrogen contamination is ubiquitous across the globe; as a result of this, the need to understand and predict the extent and effects of nitrogen contamination on microbial ecosystems is increasingly important. This paper utilises a dataset that provides a rare opportunity to observe varying contamination conditions in a single aquifer and understand the differences between potential background bores and two different types of contamination spread across the other bores. Using physicochemical and microbiological community analysis, this paper aims to determine the impacts of the two contaminants, nitrate and ammonia, on the microbial communities and the differences between polluted and physicochemical background bores. Total nitrogen (N) varied by a factor of over 2000 between bores, ranging from 0.07 to 155 mg L−1. Nitrate (NO3−) concentrations ranged from 150 to <0.01 mg L−1; ammonium (NH4+) concentrations ranged from 26 to <0.1 mg L−1. MANOVA analysis confirmed an overall significant relationship (p = 0.0052) between N variables and the physicochemical data (or status) of the three areas of contamination dubbed ‘contamination zones’. The contamination zones were defined by no known presence of contamination in the uncontaminated bores, the presence of NO3− contamination and the presence of NO3− and NH4+ contamination. PERMANOVA analysis confirmed that there was an overall significant difference in the microbial communities between the three contamination zones (p = 0.0002); however, the presence of NH4+ had a significant effect (p = 0.0012). In general, the nitrate-contaminated bores showed a decrease in the abundance of individual OTUs. We further confirmed that NH4+ contamination had a significant relationship with an increased percentage of abundance occupied by the Planctomycetota phylum (specifically the Candidatus Brocadia genus). It was found that one of the two background bores (BS-004) was likely also representative of natural microbial background, and another (BS-002) showed characteristics that may be representative of past or intermittent contamination. This paper demonstrates a possible way to determine the microbial background and discusses the potential uses for this information.

Development of a vadose zone advanced monitoring system: Tools to assess groundwater vulnerability

AbstractPerforming repeat pore‐fluid sampling over long time‐scales can provide valuable information on unsaturated zone contaminants and their potential flux to ground water. This information can be used to manage groundwater remedies and identify contaminants that need to be sequestered in the vadose zone to minimize flux to ground water. Pore‐water samples are commonly used to obtain contaminant concentrations within the vadose zone, but existing methods are limited as they only provide a single sample at one location and time. The vadose zone advanced monitoring system (VZAMS) has been designed to integrate multiple technologies into a single down‐borehole system that allows for sampling of pore fluids (liquid and gas) to provide information about contamination and hydraulic conditions at multiple depths (∼0.3‐m intervals) within a cased borehole. Testing has been completed at the laboratory scale to verify the sampling elements of VZAMS, including geochemical testing for representative contaminants known to exist at the Hanford Site, located in southeastern Washington State. Physical tests focused on the ability of the sampler to draw fluid under unsaturated conditions. Initial geochemical testing showed that the stainless steel material used with the porous cuff may affect the sampled concentrations of redox‐sensitive contaminants under very dry conditions. Additional laboratory testing demonstrated that the VZAMS components are able to collect representative samples for substances of interest under expected field conditions. In this paper, the design and functionality of a novel instrument are demonstrated in support of subsequent testing in the field.

Structure and function response of bacterial communities towards antibiotic contamination in hyporheic zone sediments

Bacterial communities are crucial for processing and degrading contaminants in hyporheic zones (HZ). However, the effects of antibiotics on HZ bacterial communities have seldom been addressed. Here, using MiSeq 16S amplicon sequencing technology, the effects of acute exposure to Enrofloxacin, Sulfathiazole, Tetracycline hydrochloride, and Penicillin V potassium on HZ bacterial communities were investigated. Results revealed that HZ sediment communities responded differently to different classes of antibiotics, reflecting the distinct selection stress of antibiotics on HZ bacterial communities. Besides, HZ communities from the locations with more severe antibiotic contamination backgrounds (∼150 μg kg−1) were more resistant towards antibiotic treatment. Compared with small/non-significant changes in HZ community diversity and composition treated with ng L−1∼ug L−1 level antibiotics compared to the control group, treatments with antibiotics over mg L−1 level significantly reduced the diversity and changed the structures of HZ bacterial communities, and enhanced the resistance of the community to antibiotics by enriching antibiotic resistant bacteria. The exposure to mg L−1 level antibiotics also changed community functions by restricting the growth of functional bacteria, such as ammonia oxidizing bacteria (AOB) Nitrosomonas, resulting in ammonia accumulation in sediments. The results implied that at field-relevant concentrations, there was no or minor effect of antibiotics on HZ bacterial community structure and functions, and only those areas with high antibiotic concentrations would have effects.

Hydrochemical characterization of groundwater quality using chemometric analysis and water quality indices in the foothills of Himalayas.

Groundwater pollution of the watershed is mainly influenced by the multifaceted interactions of natural and anthropogenic process. To analyse the spatial–temporal variation and pollution source identification and apportionment, the dataset was subjected to a globally acknowledged coherent technique using water quality indices and chemometric techniques (principal component analysis (PCA) and cluster analysis. The bulk of the samples tested were below the BIS’s permissible levels. Groundwater samples from the pre- and post-monsoon seasons mostly contained the anions HCO−3 > Cl− > SO2−4 > NO−3, while the primary cations were Ca2+ > Mg2+ > Na+ > K+. Groundwater was alkaline and hard at most of the sites. According to hydro-geochemical facies and relationships, Piper diagrams, and principal component analysis, weathering, dissolution, leaching, ion exchange, and evaporation were the key mechanisms influencing groundwater quality. The hydrochemical facies classified the groundwater samples into the Ca-Mg-HCO3 type. For all the sampling locations, PIG was determined to be 0.43, 0.52, 0.47, 0.48, 1.00, and 0.70; respectively. The majority of the test locations fell into the low to medium contamination zone, as determined by the groundwater pollution index (PIG) and contamination index. Three principal components, which together account for 93.8% of the total variance, were identified via PCA. The study’s findings confirm the value of these statistical techniques in interpreting and understanding large datasets and offering reliable information to reduce the time and expense of programmes for monitoring and evaluating water quality.