Contaminant Concentrations Research Articles

Instantaneous detection and location of contaminant sources in intelligent buildings: A distributed Kalman filter scheme

Indoor Air Quality (IAQ), as a common concern of Intelligent Buildings (IBs), is easily compromised by contaminants which may result from accidents, pathogens or terrorist attacks. Once some contaminant occurs in one zone, it will be quickly diffused to other zones through windows, doors or Heating, Ventilation and Air Conditioning (HVAC) systems, which makes detecting and locating the contaminant source a significant challenge. In this paper, a distributed Kalman filter (DKF) based scheme for detecting and locating the multiple contaminant sources is developed. Firstly, a distributed state-space model of contaminant diffusion is established with the help of the multizone simulation program-CONTAM and the Multi-Chamber theory. Then, a multi-agent based distributed monitoring framework is constructed, where each agent equipped for each zone runs a Kalman filter using both the information of the local zone and the residuals of the interconnected zones. The decoupling strategy is employed to determine the filter gains to guarantee the optimal contaminant concentration estimations. Compared with existing methods, the proposed scheme can detect and locate multiple contaminant sources instantaneously. Meanwhile, it has the advantages of low computation and communication consumptions. A model of a realistic 11-zone experimental center created on CONTAM is used to demonstrate the effectiveness and superiority of the proposed scheme.

Rapid quality control for recycled coarse aggregates (RCA) streams: Multi-sensor integration for advanced contaminant detection

Recycling coarse aggregates from construction and demolition waste is essential for sustainable construction practices. However, the quality of recycled coarse aggregates (RCA) often fluctuates significantly, in contrast to the more stable quality of natural aggregates. Contaminants in RCA notably compromise its quality and usability. Therefore, automating the quality control of RCA is necessary for the recycling industry. This study introduces an industry-focused, innovative, and rapid quality control system that combines Laser-Induced Breakdown Spectroscopy (LIBS) with 3D scanning technologies to enhance the detection of contaminants in RCA streams. The system involves a synchronized application of LIBS for spectral analysis and 3D scanning for the physical characterization of different materials. Results reveal that the dependability of single-shot LIBS analysis has been enhanced, thus elevating the precision of contaminant detection. This improvement is achieved by accounting for the laser shot's angle of incidence and focal length adjustments. The introduced technology holds potential for application in the real-time examination of substantial volumes of RCA, facilitating a rapid and reliable quality control method. This rapid assessment technique delivers online data about the concentration of contaminants in RCA, including recycled fine aggregates, cement paste, bricks, foam, glass, gypsum, mineral fibers, plastics, and wood. This data is both essential and sufficient for choosing a cost-effective mortar recipe and guaranteeing the performance of the final concrete product in terms of strength and durability in construction projects. The system can monitor the quality of RCA flows at throughputs of 50 tons per hour per conveyor, characterizing approximately 4000 particles in every ton of RCA, in this way signaling the most critical contaminants at levels of less than 50 parts per million. With these characteristics, the system could also become relevant for other applications, such as characterizing mining waste or solid biofuels for power plants.

Continental-scale nutrient and contaminant delivery by Pacific salmon.

The movement of large amounts of nutrients by migrating animals has ecological benefits for recipient food webs1,2 that may be offset by co-transported contaminants3,4. Salmon spawning migrations are archetypal of this process, carrying marine-derived materials to inland ecosystems where they stimulate local productivity but also enhance contaminant exposure5-7. Pacific salmon abundance and biomass are higher now than in the last century, reflecting substantial shifts in community structure8 that probably altered nutrient versus contaminant delivery. Here we combined nutrient and contaminant concentrations with 40 years of annual Pacific salmon returns to quantify how changes in community structure influenced marine to freshwater inputs to western North America. Salmon transported tonnes of nutrients and kilograms of contaminants to freshwaters annually. Higher salmon returns (1976-2015) increased salmon-derived nutrient and contaminant inputs by 30% and 20%, respectively. These increases were dominated by pink salmon, which are short-lived, feed lower in marine food webs than other salmon species, and had the highest nutrient-to-contaminant ratios. As a result, the delivery of nutrients increased at a greater rate than the delivery of contaminants, and salmon inputs became more ecologically beneficial over time. Even still, contaminant loadings may represent exposure concerns for some salmon predators. The Pacific salmon example demonstrates how long-term environmental changes interact with nutrient and contaminant movement across large spatial scales and provides a model for exploring similar patterns with other migratory species9.

Performance Evaluation of a Pilot-Scale Constructed Wetland with Typha latifolia for Remediation of Domestic Wastewater in Zimbabwe

The management of wastewater remains a challenge, particularly in developing countries. The potential use of constructed wetlands to treat wastewater is promising but their contaminant removal efficiencies, particularly in a tropical country such as Zimbabwe, are not fully understood. A pilot-scale study was undertaken in Zimbabwe to evaluate the efficiency of vertical-flow constructed wetlands planted with Typha latifolia in the treatment of domestic wastewater. Four pilot subsurface vertical-flow constructed wetland units (measuring 1 m × 1 m × 1.1 m) were built from concrete. The units were filled with waste rock from a nickel mine. Three units were planted with Typha latifolia while the fourth one was left unplanted, acting as the control. Each unit was loaded with wastewater at a rate of 220 dm3/day. Physico-chemical and bacteriological parameters were analyzed during the winter season. Physico-chemical and bacterial contaminant concentrations were significantly lower in the effluent than in the influent, and the system achieved maximum removals for BOD5, COD, TDS, TSS, nitrates, phosphates, phosphate pentoxide, phosphorus, and E. coli of 56.01%, 82.87%, 30.61%, 90.40% 17.26%, 35.80%, 36.19%, 40.64%, and 90.28%, respectively. The study shows that constructed wetland systems can be successfully established for the removal of physical, chemical, and microbial contaminants from domestic wastewater.

Assessment of drinking water quality and identifying pollution sources in a chromite mining region

Water sources near mining regions are often susceptible to contamination from toxic elements. This study employs machine learning (ML) techniques to evaluate drinking water quality and identify pollution sources near a chromite mine in Iran. Human health risks were assessed using both deterministic and probabilistic approaches. Findings revealed that concentrations of calcium (Ca), chromium (Cr), lithium (Li), magnesium (Mg), and sodium (Na) in the water samples exceeded international safety standards. The Unweighted Root Mean Square water quality index (RMS-WQI) and Weighted Quadratic Mean (WQM-WQI) categorized all water samples as 'Fair', with average scores of 67.95 and 67.19, respectively. Of the ML models tested, the Extra Trees (ET) algorithm emerged as the top predictor of WQI, with Mg and strontium (Sr) as key variables influencing the scores. Principal component analysis (PCA) identified three distinct clusters of water quality parameters, highlighting influences from both local geology and anthropogenic activities. The highest average hazard quotient (HQ) for Cr was 1.71 for children, 1.27 for adolescents, and 1.05 for adults. Monte Carlo simulation for health risk assessment indicated median hazard index (HI) of 4.48 for children, 3.58 for teenagers, and 2.98 for adults, all exceeding the acceptable threshold of 1. Total carcinogenic risk (TCR) exceeded the EPA's acceptable level for 99.38 % of children, 98.24 % of teenagers, and 100 % of adults, with arsenic (As) and Cr identified as the main contributors. The study highlights the need for urgent mitigation measures, recommending a 99 % reduction in concentrations of key contaminants to lower both carcinogenic and non-carcinogenic risks to acceptable levels.

Utilizing RSM-CCD for optimizing the removal of Cr(VI) and tetracycline over a new recyclable Fe3O4/SiO2/ZIF-67 composite: Isotherms, kinetics, and mechanism

Pollution of water resources by a range of organic and inorganic non-degradable contaminants is becoming increasingly problematic. This study presents a novel Fe3O4/SiO2/ZIF-67 (FSZ) nanocomposite for removing tetracycline (TC) and hexavalent chromium (Cr6+). The synthesis began with the preparation of Fe3O4, SiO2, and ZIF-67 components. Following this, various loadings of the binary SiO2/ZIF-67 were prepared. Finally, the ternary FSZ adsorbents were synthesized by impregnating 1, 3, 5, 7, and 9 wt% of Fe3O4 nanoparticles (NPs) onto the optimized binary SiO2/ZIF-67 NPs. Characterization techniques such as SEM, TEM, BET, EDS, XRD, and XPS were performed. The removal efficiencies were optimized using the RSM-CCD, considering factors like composite dosage, reaction time, pH levels, and contaminants concentration. Optimal composite dosages of 0.69 g/L for TC and 1.68 g/L for Cr6+, pH values of 6.05 for TC and 6.06 for Cr6+, reaction times of 90 min for TC and 57 min for Cr6+, and contaminant concentrations of 25.47 mg/L for TC and 2683.2 ppb for Cr6+ were achieved. Removal rates of 98.53 % for TC and 97.45 % for Cr6+ were achieved under optimal conditions. Moreover, various kinetic and isothermal adsorption models were applied. The FSZ composite maintained high removal efficiencies for Cr6+ (81.14 %) and TC (79.82 %) after four cycles. Its performance was assessed in various water types, including deionized water, river water, and municipal wastewater. Additionally, the FSZ composite effectively removed other contaminants, achieving high efficiencies for cadmium (95.18 %), lithium (83.42 %), arsenic (88.29 %), sulfamethoxazole (87.38 %), doxycycline (96.15 %), and cefixime (81.97 %). Finally, the mechanisms responsible for the removal of TC and Cr6+ were evaluated. The sustainable synthesis of FSZ provides a valuable foundation for future studies focused on Cr6+ and TC removal, offering a potential solution to pressing environmental challenges.

Ageing durability of SiR under prolonged voltage stress, contaminant flow and contaminant concentration: a statistical approach

Ageing durability of SiR under prolonged voltage stress, contaminant flow and contaminant concentration: a statistical approach

Sustainable urban water management: Evaluating two pilot-scale advanced decentralized treatment systems for removal of organic contaminants of emerging concern in reclaimed groundwater

The rapid growth of population and the effects of climate change have placed unprecedented pressure on urban water supplies and pollution control. Consequently, it is essential to explore new local water resources in water-strained areas. To this end, this work focuses on evaluating pollutant removal effectiveness of decentralized treatment systems for groundwater reclamation. Two pilot-scale treatment trains, Treatment Line 1 (L1) and Treatment Line 2 (L2), which use membrane-free (with granulated activated carbon as the main process) or membrane-based (with reverse osmosis as the primary technology), were compared for their effectiveness in reducing concentrations of organic contaminants of emerging concern (CECs). Additionally, the effect of sodium hypochlorite addition for biofilm control on the contaminant removal performance was also examined. Results from the analysis of nearly 120 trace organic compounds (only 21 were detected in the raw water) showed that L2 significantly overperformed L1. Furthermore, the addition of a pre-chlorination step did not improve the removal performance. Regarding trace organic compounds, L1 without pre-chlorination averaged an overall good removal performance (94 ± 12%). However, Irbesartan, gemfibrozil and gabapentin showed moderate removals (50–90%) and Valsartan was poorly removed (<50%). After pre-chlorinating L1, the overall removal performance decreased (86 ± 20%). Nearly one third of the target contaminants showed moderate removal (50–90%), with Irbesartan and Valsartan exhibiting poor attenuations (<50%), highlighting that negatively-charged compounds were challenging to eliminate. In contrast, L2 exhibited very high removals (>99%) on all studied trace organic contaminants regardless of pre-chlorination. Our study also identified several indicator compounds to monitor CEC removal. Finally, considering the trade-offs between cost and final water use (non-potable), L1-based schemes with intermittent pre-chlorination could be the preferred implementation option. The results of this work will offer valuable insights into decentralized treatment systems, assisting decision-makers in choosing suitable approaches for sustainable urban water management.

Histological Based Environmental Monitoring of the Lower Nun River: Using the Histo-morphometry of Kidney, Gills, Liver, and Testes of Coptodon zillii

It is an ecotoxicological study aimed at using chemical and bio-monitoring methods to pollution status of the Lower Nun River (LNR) basin using the histo-morphometry of the Liver, Kidney, Gills, and the Testes of Coptodon zillii. Based on literature review on the environmental burdens of the LNR, the following Target Chemicals (TC) were chosen for the study: Cadmium (Cd), Chromium (Cr), Copper (Cu), Nickel (Ni) and Lead (Pb). The study involved the sampling of water, sediment and feral fish from two stations along the LNR, Peremabiri (PER) and Igbomotoru(IGB) – Experimental sites.Water and sediment samples were analyzed to ascertain the physico-chemical concentrations of potential contaminants, while the harvest fish organs of liver, kidney, gills and testes were subjected to histological study to ascertain the exposure effect. Control fishes were harvested from African Aqua-culture Centre (ARAC) – Reference Site. Analyzed sediment and water values were used to evaluate Environmental Water Quality Index (EWQI) and sediment quality, while the fish organs were analyzes and used for pollution certification and stratification. Study results showed that EWQI of PER was poor (41.9); sediment quality showed that Cr, CU and Pb were above the Maximum Allowable Toxicant Concentration (MATC) for fresh water body. Fish from IGB showed worse lesion prevalence and organ histopathologic Index (Iorg) when compared to PER, with ARAC having the best outcome. The environmental pollution status (EPS) LNR was normal at PER and was slightly polluted at IGB. The study gave credence to the use of histology as a biomarker to assess sublethal effects of environmental stressors, and in determination of the pollution status.

Statistical analysis and optimization of mechanical-chemical electro-Fenton for organic contaminant degradation in refinery wastewater

Refinery wastewater (RWW) poses significant environmental challenges due to its high concentration of organic contaminants, necessitating effective treatment solutions. This study employs the mechanical design of the Electro-Fenton (EF) technique as a feasible alternative for treating RWW. The anode and cathode electrodes, made of stainless steel and iron, respectively, were utilized to conduct organic removal (OR) from RWW. To maximize performance, two metric optimization design techniques were examined: Box Behnken Design (BBD) and response surface methodology. The analysis of variance revealed a high coefficient of determination value (R2 = 0.9685), indicating a second-order provable relationship between the response and self-governing variables. Additional statistical analysis was performed to assess the validity and reliability of the suggested approach. A predictive regression model was developed based on unresolved values, demonstrating a high level of agreement with experimental values. This model identified the optimal equation for the empirical model to predict OR based on predetermined parameters. Based on the BBD, the percentage of OR reached 93.45 % at pH 3, temperature, and electrolysis time of 60 °C, and 30 minutes, respectively. The implications of this study suggest that the optimized Electro-Fenton technique could serve as a robust solution for addressing the environmental impact of RWW, contributing to sustainable wastewater management practices.

Predicting the spread of contamination in water distribution networks laid on sloping terrains

Contamination in domestic and drinking water during the conveyance process is one of the biggest health risks of all time. This is a very common hazard that is expected in the areas where water, sewer, and drainage pipes are laid in trenches near each other. The extent of the contamination spread in the case of intrusion through a pipe leak for water distribution networks (WDNs) laid on sloping terrain is not known. This article deals with the simulation and hydraulic analysis of organic contaminant intrusion in WDNs with significant consideration of the slope of the laid pipes. The source of organic contamination is considered to be the nearby leaking sewer water. The effects of sloping terrain on contaminant spread in the pipe network are studied in detail by injecting contaminant concentrations at eight different critical locations in the network. The results of contamination spread after a particular time at all nodes are compiled, and by using statistical techniques, a relation between the contaminant spread and pipe slope is proposed. The presented model is validated by comparing the actual values of the contaminant in water samples obtained at the site with the calculated ones, and it shows that the values deviate within the range of ±2% only, which is considered a good match. The research proves to be beneficial for the management of water distribution through pipe networks against contaminants to maintaining water quality and public health.

Prediction of biomarker peak of infrared spectra between pork fat and chicken meat fat using fourier transform infrared spectroscopy technique and clotter plot method

The increasingly widespread contamination of chicken meat by pork requires a method to identify the presence of these contaminants quickly and cheaply. Apart from analyzing the spectrum of various pure animal fats, this research also aims to vary the concentration of pork fat and chicken fat to know the FTIR peak spectrum, which will change with changes in concentration. The presence of spectral peaks that change can be identified due to changes in pork fat concentration, which also shows a typical peak spectrum position in pork fat. Variations in the concentration of pork fat contaminants in chicken fat consist of the ratio of the mixture of pork fat (PF) and chicken fat (CF), namely 90:10 (PC1), 80:20 (PC2), 70:30 (PC3), 60:40 (PC4), 50:50 (PC5), 40:60 (PC6), 30:70 (PC7), 20:80 (PC8), and 10:90 (PC9). A scatter plot, a graph usually used to see the relationship pattern between 2 variables, is employed in this research to visualize the changes in spectral peaks with varying concentrations of pork fat in chicken fat. The data scale must be an interval and ratio scale to use a scatter plot. Biomarker wavelengths were identified from the spectra of four animal fats and palm oil at positions 2948.9 and 3007 cm−1, separated by four animal fats and palm oil at a certain distance, thus indicating that these wavelengths could be used to identify non-halal samples. Keywords: Chicken, Clotter plot, Fat, Infrared, Meat, Pork, Spectra

Review: Urban Water Security and Safety

“Water security” and “water safety” is defined differently. As the terms are related they may lead to confusion and misinterpretations, depending on the context. Water security generally refers to a lack of resources of an acceptable quality, i.e. water scarcity that may be related either to an excess of water demand or drought impacts (with links to climate change and e.g. salt water intrusion into coastal aquifers). Further, water security is closely related to food security, energy security, health security and ecological security. From a (human) security viewpoint, however, water security may also be understood in the light of possible intentional degradation of the resources, e.g. criminal or terrorist act leading to a deliberate (chemical or biological) contamination of water supply systems. Water safety on the other hand refers to the quality or chemical status of the water resources that has to comply with the defined quality standards for drinking water specifically to protect human health, both from elevated concentrations of contaminants and natural geogenic elements. This review gives a snapshot of various (ground)water safety and security issues written by authors from different sectors and disciplines. Illustrating and clarifying the many societal challenges related to water security and safety in cities.

P-Phenylenediamines and p-phenylenediamine quinone derivatives in rubber consumer products and typical urban dust: Sources, transformation profiles, and health risks

N,N′-Substituted p-phenylenediamines (PPDs) are widely used as antioxidants in the rubber industry and are released into the environment in large quantities during the production and use of rubber products. We quantified PPDs and PPD quinone derivatives (PPD-Qs) in rubber consumer products, including car tires, rubber belts, rubber gloves, rubber cables, and rubber hoses, to obtain information on the degree of weathering over time during their use. Additionally, we investigated the occurrences and sources of PPDs and PPD-Qs in dust samples collected from four typical urban environments (roads, parking lots, automotive repair shops, and residences). The detected compounds included the highly toxic N-(1,3-dimethylbutyl)-N′-phenyl-1,4-phenylenediamine quinone, which can cause acute mortality of coho salmon (Oncorhynchus kisutch). Concentrations of PPDs in the automotive repair shops reached 56.0 μg/g, and were much higher than in the other environments, while the residential samples had the lowest contaminant concentrations. In road and residential samples, N,N′-di-2-naphthyl-p-phenylenediamine accounted for 17 %–30 % of the PPDs, and may have originated from different sources. We preliminarily identified 32 transformation products, and 11 of these were N,N′-di-2-naphthyl-p-phenylenediamine transformation products. The average daily intakes of PPDs and PPD-Qs were calculated to assess the health risks of dust exposure in each environment. Workers had high total intakes of PPD [60.3 ng/(kg day)] and PPD-Qs [20.1 ng/(kg day)], and were at some risk of occupational exposure. These results improve our understanding of the environmental occurrences, sources, transformation, and health risks of PPDs and PPD-Qs.

The role of Ni- and Cd-resistant rhizobacteria in promoting the growth of rice seedlings and alleviating the combined phytotoxicity of Ni and Cd

The problem of potentially toxic metal pollution is increasingly acute with the development of human society. In this study, we investigated the remediation of nickel (Ni) and cadmium (Cd) co-contamination through inoculating rice with three new-isolated Ni- and Cd-resistant plant growth-promoting rhizobacteria (PGPR) Y3, Y4, and Y5. These three strains possessed growth-promoting properties, including 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, the ability of indoleacetic acid (IAA) production, phosphate solubilization, siderophores production, and exopolysaccharide (EPS) development. According to 16S rDNA sequence homology, strains Y3, Y4, and Y5 were identified as Pseudomonas sp., Chryseobacterium sp., and Enterobacter sp., respectively. Based on the results of rice germination experiments conducted under combined toxicity, we set the contamination concentrations for Ni2+ at 20 μg mL−1 and Cd2+ at 40 μg mL−1. Then we conducted potting experiments at these concentration levels to study the effects of strains Y3, Y4, and Y5 on rice growth under synergistic Ni and Cd stress. The results indicated that the inoculated strains Y3, Y4, and Y5 were effective in promoting the growth of rice seedlings under the combined stress of Ni and Cd, and conferring tolerance to Ni and Cd by increasing the antioxidant enzyme activities of the seedlings. Among them, strain Y3 exhibited stronger ACC deaminase activity, IAA production capacity, and EPS production capacity, showing the most pronounced growth-promoting effect on rice. It was demonstrated that after inoculation with strain Y3, the germination rate of rice seeds increased by 43 %, the fresh weight of stems improved by 35 %, and the chlorophyll content enhanced by 70 % and other growth-promoting phenomena. Additionally, under Ni and Cd stress, strain Y5 performed better than strain Y4 in terms of IAA production capacity and its influence on rice root growth, suggesting that IAA production might play a specifically essential role in root growth under Ni and Cd stress.

The use of R code for modeling and simulation of 2-D contaminant migration through a soil for the pulse source

&lt;p&gt;In this study, based on an existing analytical solution for the two-dimensional transport of contaminants in a saturated soil layer, for the pulse source, the R program code was developed. The simulation is used to obtain the profiles of contaminant concentration, for a steady groundwater velocity, as a function of distance from the source and time. The problem is analytically solved by leveraging the similarity between the Gaussian (normal) distribution and contaminant concentration distribution, the development of the analytical model (i.e., solution of partial differential equation) by using this similarity is explained step by step since it may be of interest to researchers. Contaminant propagation is modeled using R software, which helps to understand how contaminants migrate through a saturated soil layer. This approach aids in comprehending the mechanisms and spatial dynamics of contaminant dispersion, facilitating the prediction and management of soil and groundwater contamination. The provided R code can be altered for different parameters and time intervals.&lt;/p&gt;

The use of R code for modeling and simulation of 2-D contaminant migration through a soil for the pulse source

&lt;p&gt;In this study, based on an existing analytical solution for the two-dimensional transport of contaminants in a saturated soil layer, for the pulse source, the R program code was developed. The simulation is used to obtain the profiles of contaminant concentration, for a steady groundwater velocity, as a function of distance from the source and time. The problem is analytically solved by leveraging the similarity between the Gaussian (normal) distribution and contaminant concentration distribution, the development of the analytical model (i.e., solution of partial differential equation) by using this similarity is explained step by step since it may be of interest to researchers. Contaminant propagation is modeled using R software, which helps to understand how contaminants migrate through a saturated soil layer. This approach aids in comprehending the mechanisms and spatial dynamics of contaminant dispersion, facilitating the prediction and management of soil and groundwater contamination. The provided R code can be altered for different parameters and time intervals.&lt;/p&gt;

Fish Health Altered by Contaminants and Low Water Temperatures Compounded by Prolonged Regional Drought in the Lower Colorado River Basin, USA.

The goal of this study was to assess health of male Common Carp (carp, Cyprinus carpio) at four sites with a wide range in environmental organic contaminant (EOC) concentrations and water temperatures in Lake Mead National Recreation Area NV/AZ, US, and the potential influence of regional drought. Histological and reproductive biomarkers were measured in 17-30 carp at four sites and 130 EOCs in water per site were analyzed using passive samplers in 2010. Wide ranges among sites were noted in total EOC concentrations (>10Xs) and water temperature/degree days (10Xs). In 2007/08, total polychlorinated biphenyls (tPCBs) in fish whole bodies from Willow Beach (WB) in the free-flowing Colorado River below Hoover Dam were clearly higher than at the other sites. This was most likely due to longer exposures in colder water (12-14 °C) and fish there having the longest lifespan (up to 54 years) for carp reported in the Colorado River Basin. Calculated estrogenicity in water exceeded long-term, environmentally safe criteria of 0.1-0.4 ng/L by one to three orders of magnitude at all sites except the reference site. Low ecological screening values for four contaminants of emerging concern (CEC) in water were exceeded for one CEC in the reference site, two in WB and Las Vegas Bay and three in the most contaminated site LVW. Fish health biomarkers in WB carp had 25% lower liver glycogen, 10Xs higher testicular pigmented cell aggregates and higher sperm abnormalities than the reference site. Sperm from LVW fish also had significantly higher fragmentation of DNA, lower motility and testis had lower percent of spermatozoa, all of which can impair reproduction. Projections from a 3D water quality model performed for WB showed that EOC concentrations due to prolonged regional drought and reduced water levels could increase as high as 135%. Water temperatures by late 21st century are predicted to rise between 0.7 and 2.1 °C that could increase eutrophication, algal blooms, spread disease and decrease dissolved oxygen over 5%.

Brownfield Topsoil Vertical Heterogeneity: Implications for Germination and Soil Microbial Functioning.

Soil vertical heterogeneity refers to the variation in soil properties and composition with depth. In uncontaminated soils, properties including the organic matter content and nutrient concentrations typically change gradually with depth due to natural processes such as weathering, leaching, and organic matter decomposition. In contaminated soils, heavy metals and organic contaminants can migrate vertically through leaching or root uptake and translocation by plants and macrobiota, if present, leading to vertical heterogeneity in contaminant concentrations at different depths. Contaminants can alter soil properties, and we investigated the implications of soil vertical heterogeneity for germination and microbial functioning. We collected soil from an urban brownfield and created two conditions: structured soil samples collected with the soil core intact and mixed (unstructured) samples. When planted, the germination rate was significantly lower in the structured conditions (3.1 ± 1.7%) compared to mixed soils (17 ± 4.6%), suggesting that the vertical heterogeneity of contaminated soil influenced plant germination. To map the vertical distribution of contaminants and nutrient cycling rates in the structured soil samples, we collected 10 cm-deep soil cores from the barren site and a neighboring vegetated reference site and measured heavy metal concentrations, soil enzyme activities, and organic matter content in five 2 cm vertical layers. In the barren soil cores, metals were found concentrated in the top 2 cm layer, while in the vegetated soil cores, metals were uniformly distributed. No significant differences were observed for the organic matter content or moisture along depth. Published studies on vertical distribution of enzyme activities and metal concentrations have treated the top 10-20 cm as a single layer and thus would have not revealed the thin (<2 cm thick) metal cap on the surface of the barren soil core. Despite the metal cap, enzyme activities in the top layer were similar to those in the lower layers of the barren soil core, suggesting that high metal concentrations do not limit soil enzyme activity under all circumstances. Investigating vertical heterogeneity in postindustrial soils can inform efforts to convert industrial barrens to vegetated environments.

Biological Hazard Behind Lao Cuisine: Microbial Quantities and Efficacy of Difference Cleaning Detergents for Fresh Vegetables

This research aims to investigate the prevalence of bacterial hazards in fresh lettuce and peppermint sold in Nonkoh and Thatluang organic markets in Vientiane during dry and rainy seasons. Microbial counts were determined using Escherichia coli and Coliform plate count (3M PetrifilmTM) in two freshly consumed vegetables. To reduce microbial contamination, five different solutions were evaluated, including sodium chloride (NaCl) at 5 g/L (T1), viagra juice (CH3COOH) at 50 ml/L (T2), breaking soda (NaHCO3) at 5 g/L (T3), potassium permanganate (KMnO4) at 0.2 g/L (T4) and tap water is a control (T0). The results showed that the number of E.coli in lettuce was ranged from102 - 2 × 105 CFU/g and from 2 × 105 - 2 × 106 CFU/g in peppermint, exceeding the safety limit by Codex (&lt;106 CFU/g). The coliforms counts were similar in both vegetables ranged from 2 × 105 - 2 × 106 CFU/g in lettuce and from 105 - 2 × 106 CFU/g in peppermint. During the dry season, E. coli was more prevalent in the Thatluang organic market (3.77 Log10 CFU/g) than in the Nonkoh market (2.33 Log10 CFU/g), but during the rainy season, both markets had similar results. The concentration of microbial contaminants in peppermint did not differ between the two seasons. In the cleaning experiment showed that T4 the most effective solution for reducing E. coli and Coliform levels, achieving reductions of 0.7-1.9 Log10 CFU/g (35.2-54.6%), and 2.0-2.2 Log10 CFU/g (33.6–39.1%), respectively. Therefore, a concentration of potassium permanganate (KMnO4) 50–100 mg/L (50-100 ppm) is recommended for vegetable cleaning purposed.