Poor Water Quality Research Articles

Exploring the complexities of slum vulnerability in Haryana, India: a qualitative research journey into economic, social, physical, and health dimensions

ABSTRACT Purpose The study explores the conditions contributing to slum dweller’s vulnerability to poor health and examines interplay between economic, physical/infrastructural, and social factors affecting health status to inform policy and programme. Methods The methodology deployed for data analysis was mixed deductive-inductive. A deductive framework was adapted for categorizing the data into four broad themes: Economic, Physical/Infrastructure, Social, and Health. Using Braun and Clarke’s principle, we also mapped sub themes based on researchers’ insights with the experiences shared by the slum populations. The study was conducted across 13 districts in slum areas to gather information from vulnerable groups based on the 40 focus group discussions. Findings Poverty serves as a primary driver of domestic/internal migration from rural to urban areas, aggravating issues such as illiteracy, unemployment, and inadequate living conditions, which predispose slum dwellers to various health problems. Limited access to food, poor water quality, and improper waste disposal further compound health risks. People living in slums face economic, social, and physical vulnerabilities leading to health vulnerability and outcome. Conclusions Enhancing the health and well-being of slum dwellers requires adopting an integrated and comprehensive approach of policy intervention, community mobilization, and multisectoral intervention.

Diatoms as an Indicator of Water Quality in the Kuils River, Western Cape, South Africa

Rivers are crucial hydrological cycle components, supporting ecosystems and human activities. Managing and protecting river water quality is essential. Diatoms, microscopic algae, are widespread and sensitive to changes in water quality, making them effective bioindicators. This study focused on the Kuils River in the Western Cape, South Africa, where diatom sampling was conducted at four sites. Their communities are affected by different physicochemical parameters, such as changes in pH, salinisation, eutrophication, and organic enrichment. A total of 98 diatom species were identified. The Omnidia software was used to calculate the Generic Diatom Index, Specific Pollution Index, and Trophic Diatom Index. Historical physicochemical data such as pH, chemical oxygen demand, and phosphorus were obtained from the Department of Water and Sanitation between 2019 and 2021 and were used to provide a reference for comparing diatoms. The results showed clear signs of pollution, as shifts in diatom species composition were observed. Pollution-tolerant species such as the Nitzschia palea (Kützing) W Smith 1856, Navicula viridula (Kützing) Ehrenberg 1838, Eunotia bilunaris (Ehrenberg) Schaarschmidt 1880, and Ulnaria ulna (Nitzsch) Compère 2001 dominated, while less pollution-tolerant species like Gomphonema parvulum f.saprophilum Lange-Bertalot and E. Reichardt 1993 and Stephanocylus meneghinianus (Kutzing) Kulikovskiy, Genkal, and Kociolek 2022 were less abundant. Both diatom indices and physicochemical data indicated poor water quality in the Kuils River. The study concludes that diatoms are a valuable tool for biomonitoring river water quality and recommends their use alongside traditional physicochemical methods for future assessments of river systems.

Water Quality Assessment using Selected Macroinvertebrate Based Indices and Water Quality Index of Sungai Air Hitam Selangor

A study was conducted from July to December 2022 at Sungai Air Hitam, a small tributary of the Selangor River located within the Tanjung Karang Sub-basin in Malaysia (coordinates: 3° 24' 27" N, 101° 25' 54" E to 3° 28' 14" N, 101° 26' 59" E). This confluence is situated near three major downstream water treatment plants. The study assessed six water quality parameters—pH, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), ammonia (NH3), and suspended solids (SS)—to calculate the Water Quality Index (WQI). Macroinvertebrates were sampled simultaneously using the dipping net method to obtain biotic indices for further evaluation of water quality. The results indicated that the WQI classified Sungai Air Hitam as Class III, with scores ranging from 56.9 to 64.6, suggesting the river is suitable for water supply and fisheries. However, the Biological Monitoring Working Party (BMWP) index categorized the water quality as poor, with scores between 30 and 42. Similarly, the Average Score Per Taxon (ASPT) ranged from 3.25 to 5.25, indicating pollution or environmental impact, while the Family Biotic Index (FBI) further classified the river as having poor to very poor water quality, with scores between 6.57 and 8.11. Overall, the study suggests that Sungai Air Hitam has experienced some degree of ecological degradation. These findings emphasize the need for continuous monitoring and remediation efforts to preserve and restore water quality.

Growing mismatches of supply and demand of ecosystem services in the Netherlands

A sufficient supply of goods and services from ecosystems is vital to ensure human well-being. This study evaluates whether the demand for goods and services within the Netherlands is met by Dutch ecosystems, could otherwise be provided through technology and/or by imports, or remains (partially) unmet. Additionally, this study shows the dynamics of supply and demand of these services over time. The results reveal that no ecosystem service supply is fully meeting the total demand provided by Dutch ecosystems. Additionally, for the majority of the services (10 out of 17), the gap between supply and demand widened over the last two decades, indicating a growing mismatch. Imports and technology only partly close the gap between supply and demand. The growing mismatch between supply and demand is expected to lead to increasing negative impacts on human well-being, such as poor air and water quality, heat stress in urban areas, increasing flood risks, limiting opportunities for outdoor recreation and loss of biodiversity. Our findings show that current policy goals to maintain and restore ecosystem services are not on track in the Netherlands. Urgent action is necessary to enhance the sustainable utilization of natural resources and to optimize the balance between supply and demand. Priority should be given to goods and services facing unmet demand where imports or technological solutions are not feasible, particularly those where the gap between supply and demand is widening.

Acoustic‐tagged American Shad utilize historic habitat following dam removal in northern Delaware

AbstractObjectiveThe anadromous American Shad Alosa sapidissima, a once commercially important species in the mid‐Atlantic region, experienced population declines due to overfishing, poor water quality, and impediments to accessing freshwater spawning habitat. Efforts at the regional and national scale substantially addressed the former two obstacles to facilitate population growth, but dam modifications or removal are still ongoing. In 2019, the state of Delaware removed the first barrier to anadromous fish passage on the Brandywine River (a tributary of the Delaware River), Dam 1.MethodsA total of 24 American Shad were surgically tagged with acoustic transmitters from 2021 to 2022 above recently removed Dam 1 and tracked in the Delaware River estuary and coastal waters of the Atlantic Ocean.ResultThe length of available habitat increased by 1.3 km, and 75.0% of surgically tagged American Shad used historic spawning grounds in the Brandywine River following dam removal. Nine individuals exhibited long‐term residency in the Brandywine River from May to June, demonstrating the importance of this newly available habitat to spawning adults. Additionally, one fish returned to the Brandywine River between years, displaying interannual spawning site fidelity and iteroparity. We also observed exploratory behavior of three additional American Shad that exited and returned to the Brandywine River within the same year.ConclusionOverall, we document a successful collaborative network via receiver array maintenance to answer questions regarding anadromous fish migration and habitat use following dam removal.

Effects of Channelization on Macroinvertebrate Assemblages in a Small Stream: The Case of Awetu in Jimma City, Ethiopia

Freshwater ecosystems are increasingly modified worldwide by anthropogenic activities. Land use change is one of the leading factors responsible for stream ecosystem degradation. Physical habitat disturbance due to channelization is among the factors responsible for the loss of biodiversity and degradation of river water quality worldwide. Since 2020, Jimma City municipality has been beautifying the city and one of the activities is channelizing using concrete embankment, a part of the Awetu stream that runs through the city. The main aim of this study is to assess the effect of channelization on macroinvertebrate assemblages and the water quality of the Awetu stream. A cross-sectional study was conducted in April 2022. Macroinvertebrates, water samples, and habitat data were collected from 21 sampling sites along the three segments of the stream (upstream, channelized, and downstream). Data were analyzed for different macroinvertebrate metrics and water quality parameters. Canonical Correspondence Analysis was used to examine the overall relationship between macroinvertebrate assemblages and water quality parameters. The upstream site has better macroinvertebrate assemblages than channelized and downstream sites (p<0.05). The downstream site showed better assemblage compared to the channelized site, though it was not significant. Regarding water quality parameters, a significant variation was observed between channelized and, un-channelized sites (upstream and downstream) (p<0.05). The habitat condition score varied from 47 (poor) at channelization to 150 (suboptimal) upstream. Upstream sites were found to have relatively better macroinvertebrate assemblages, better water quality, and good habitat conditions. The downstream sites had lower macroinvertebrate assemblages, poor habitat conditions, and degraded water quality compared to the upstream sites. The channelized segment had the poorest habitat, with poor macroinvertebrate assemblages and water quality. Thus, the conservation of habitat conditions along the channelized segments of the Awetu stream is recommended to improve the water quality and macroinvertebrate assemblage.

Evaluation of the migration and environmental effects of metal elements within cementitious gangue-fly ash backfill in underground coal mines

Cementitious gangue-fly ash backfill (CGB) is used as a green mining technology worldwide. However, under the coupled effects of geological stress and groundwater, the metal elements in the CGB tend to migrate into nearby strata, which can consequently result in pollution of the groundwater environment. In this paper, the influence of initial pH and stress damage on the migration behavior of metal elements in CGB is quantitatively studied through the multi-physical field coupling model of stress-permeability-concentration. The enhanced Nemerow index evaluation method is used to comprehensively evaluate the impact of these metal elements migration behaviors on the groundwater environment. The research results show that: (1) When the stress damage of the CGB increases from 0.76 to 0.95, the Darcy velocity at the bottom of the CGB first increases, then decreases, and finally stabilizes at 2.01 × 10−7 m/s. The longest time to reach the maximum Darcy velocity is 3 a. (2) When the damage of the CGB is 0.95, the farthest migration distances of Al, Cr, Mn, Fe, Ba, and Pb are 40.8, 34.0, 29.8, 31.9, 38.8 and 32.1 m, respectively. (3) The alkaline environment stimulates the migration of Al, Cr, Fe, Mn, and Pb, whereas Ba migrates farther under acidic conditions. The farthest migration distance of Ba is 31.6 m under pH 3. (4) The enhanced Nemerow index indicates that when stress damage increases from 0.76 to 0.95, the areas with poor water quality increase from 0 to 1.71 %, and no area is classified as very poor grade. When the initial pH changes from 3 to 11, 100 % of the region is classified as fair or above. The initial pH of the CGB has a relatively slight influence on the groundwater environment. This study provides experimental data and theoretical basis for the environmental evaluation of CGB.

Parasitic intestinal infection in students of disabilities centers in Sanaa governorate, Yemen

Background: Intestinal parasite infections remain prevalent in low-income countries, especially among children, due to poor drinking water quality and insufficient personal and environmental cleanliness. This study sought to diagnose, prevent, and manage intestinal parasites in individuals with special needs in Sanaa Governorate. Method: We collected stool samples from 232 students, aged 1 to 18, of which 143 were male and 89 were female. We collected data using a validated standard questionnaire. We processed and analyzed fecal samples using a wet mount preparation, adhering to the standing concentration technique. Results: We found an overall prevalence of intestinal parasitic infection of 83.6%. E. histolytica (76.7%), G. lamblia (8.6%), A. lumbricoides (0.4%), H. nana (6.5%), S. mansoni (0.4%), Ent. vermicularis (6.5%), and S. stercoralis (2.2%). Conclusions: In children, E. histolytica was the most common intestinal parasite infection. There are few methods of transmission and protection for students with special needs.

Biodegradation-assisted removal of sulfur-based odor compounds in rural drinking water using durable chitosan/polyvinyl alcohol biochar aerogels

Rural drinking water often suffers from unpleasant odors like dimethyl sulfide (DMDS) and dimethyl trisulfide (DMTS) due to poor raw water quality and limited treatment options. This study introduces durable chitosan/polyvinyl alcohol (PVA) biochar aerogels-supported bioflims in ultrafiltration (BAB-UF) reactors, where the incorporation of PVA significantly enhances structural integrity, biodegradation resistance, and functional lifespan, providing an efficient, sustainable solution for removing odorous compounds from rural water. Experimental results showed the enhanced chitosan/PVA porous biochar aerogels (CPPCA) displayed excellent biocapacity and structural stability. After 63 days of continuous operation, the degradation rate of biochar aerogels with 0.2 wt% PVA (CP2PCA) was only 8.2 %. The one-step membrane reactors utilizing PVA-enhanced aerogels achieved removal efficiencies for DMDS/DMTS pollutants of up to 98.4 %, surpassing systems without PVA. These findings indicate the potential for improved aerogels in rural drinking water treatment, providing a viable solution for effective and low-maintenance water purification.

Analysis of Human Resources Quality in Seaweed Production Development in Sumenep

This research highlights the need for an integrated approach to enhance human resource quality for the sustainable development of seaweed production in Sumenep Regency. By focusing on Pagar Batu Village, Saronggi District, a significant seaweed-producing area, this study aims to support community welfare, particularly for coastal communities. Using a descriptive qualitative method with a case study approach, the research explores the dynamics of local seaweed cultivation, focusing on conditions as they naturally occur. Data collection involved observations, interviews, and documentation to capture a comprehensive view of seaweed production. Findings reveal both supporting factors, such as cooperative teamwork and adequate equipment, and obstacles like unpredictable weather, poor water quality, and fluctuating prices. Training programs organized by local authorities show potential in increasing technical knowledge, though outreach is still limited. This research underscores the importance of capacity building and technical training to address these challenges, fostering sustainable productivity and economic growth in Sumenep's seaweed sector.

Spatial-Temporal Characteristics and Driving Factors of Surface Water Quality in the Jing River Basin of the Loess Plateau

Water quality safety in the water source constitutes a crucial guarantee for public health and the ecological environment. This study undertakes a comprehensive assessment of the water quality conditions within the Jing River Basin of the Loess Plateau, emphasizing the spatial and temporal characteristics, as well as the determinants influencing surface water quality in the Shaanxi section. We utilized data from seven monitoring stations collected between 2016 and 2022, employing an enhanced comprehensive Water Quality Index (WQI) method, redundancy analysis (RDA), and Spearman’s correlation analysis. The results show that the average annual WQI value of the water quality of the Shaanxi section of the Jing River increased from 68.01 in 2016 to 76.18 in 2022, and the river’s water quality has gradually improved, with a significant improvement beginning in 2018, and a series of water quality management policies implemented by Shaanxi Province is the primary reason for the improvement. The river’s water quality has deteriorated slightly in recent years, necessitating stricter supervision of the coal mining industry in the upper section. The river has an average WQI value of 73.70 and is rated as ‘good’. The main pollution indicators influencing the river’s water quality are CODMn, COD, BOD5, NH3-N, and TP. From the upstream to the downstream, the water quality of the river shows a pattern of increasing and then decreasing, among which S4 (Linjing Bridge in Taiping Town) and S5 (Jinghe Bridge) have the best water quality. The downstream part (S6, S7) of the Jing River near the Weihe River has poor water quality, which is mostly caused by nonpoint source contamination from livestock and poultry rearing, agricultural activities, and sewage discharge. Redundancy analysis revealed that the spatial scale of the 2500 m buffer zone best explained water quality changes, and the amount of bare land and arable land in land use categories was the key influencing factor of river water quality.

Integrating Hydrodynamic Modeling with Ecological Risk Assessment for Selecting Sites for Artificial Reef Deployment: Avoiding Coastal Pollution Risks in Kish Island, Persian Gulf

The decline of natural coral reefs has spurred interest in artificial reef construction and reef rehabilitation efforts. However, many restoration programs are failing because of poor water quality and localized pollution factors. This paper examines one etiology of coral restoration failure, highlighting the need for careful site selection based on hydrodynamic, biological, and pollution criteria. Using Kish Island as a case study, we outline a procedure for determining placement of artificial reefs to minimize external pollution impacts, which could be applied to any reef site worldwide. Our integration of computational modeling and geographic information systems enables the tracking of pollution dispersion and increases the power of restoration efforts. The RQ Plume modeling, used alongside compound pollutant modeling, can identify hotspots with the highest potential to degrade marine environments, particularly reefs. Conservation efforts should prioritize pollution mitigation, as seen in the case of sunscreen pollutants at Kish Island, where regulatory action and public education can contribute to reef protection. This comprehensive approach underscores the critical role of water quality in successful reef restoration and conservation strategies.

Unravelling integrated groundwater management in pollution-prone agricultural cities: A synergistic approach combining probabilistic risk, source apportionment and artificial intelligence

Groundwater is vital for agricultural cities, but intensive farming and fertilizer use have increased contamination risks, particularly for non-carcinogenic health hazards. This study reveals the sources of contaminants in groundwater, their health impacts, and targeted strategies in such cities. The study analyzed 115 groundwater samples, with the main groundwater chemical type being HCO₃-Na·Ca. Significant exceedances were found in Mg²⁺, HCO₃−, F−, total hardness (TH), and Mn, with HCO₃− and Mg²⁺ surpassing standards in nearly all samples. The average Comprehensive Environmental Water Quality Index (CEWQI) was 100.68, indicating that overall groundwater quality in the study area is good. High-quality water is mainly found near reservoirs and rivers, while urban and eastern regions have relatively poorer water quality. The proportion of groundwater unsuitable for drinking is low. Monte Carlo risk assessments revealed that F− and NO₃− pose non-carcinogenic risks to both adults and children, with NO₃− presenting a higher potential health risk. The Positive Matrix Factorization (PMF) model identified that groundwater pollution primarily results from natural geological processes and human activities, with agriculture being the major anthropogenic factor. AI-based zoning strategies highlighted industrial areas and high-fluoride zones as critical areas requiring enhanced prevention and control measures.

Monitoring soil salinization and waterlogging in the northeastern Nile Delta linked to shallow saline groundwater and irrigation water quality

Soil salinization and waterlogging are critical environmental issues affecting agricultural productivity and cultural heritage preservation, particularly in arid regions. This study investigated soil degradation processes in the archaeologically and agriculturally significant northeastern Nile Delta of Egypt. The objective was to assess the severity of soil degradation and identify key drivers related to water resources and soil characteristics to aid in the development of management strategies. The research employed a multi-faceted approach, including hydrochemical analyses (of groundwater, irrigation water, and soil), water quality indices calculations, statistical analyses, and satellite data. The results revealed high levels of soil salinization in the northern and central areas, with 64% of soil samples classified as strongly and very strongly saline. Soil chemistry indicated salinization sources linked to sodium chloride dominance. Satellite data from Sentinel-2 images and SRTM digital elevation data showed widespread severe waterlogging in the northern lowlands. The Irrigation Water Quality Index (IWQI) values indicated that 87.5% of irrigation water samples posed severe restrictions due to high salinity and sodium hazards, which were mismatched with the low soil permeability observed in 81% of the collected samples exhibiting clay texture and covering most of the study area. Furthermore, shallow groundwater at depths of 0.5–3 m with high salinity was detected, where total dissolved solids exceeded 20,000 mg/L, and Na-Cl water types prevailed, indicating saltwater intrusion. A strong positive correlation (r > 0.83) was found between shallow saline groundwater and soil salinity. The combination of poor irrigation water quality, shallow saline groundwater tables, and low-permeability soils created a synergistic effect that severely compromised soil health and agricultural productivity. It also posed severe risks to the structural integrity of archaeological sites and buried artifacts through accelerated physical and chemical weathering processes. This necessitates an urgent mitigation strategy to combat soil degradation in this critical area.

Spatiotemporal Dynamics of Water Quality: Long-Term Assessment Using Water Quality Indices and GIS

The severe contamination of groundwater supplies in rural areas is a global problem that requires strict environmental measures. Related to this, one of the most important challenges at present is the elimination of local sources of pollution. Therefore, this research examined the local water quality changes following the construction of the sewerage network, under the framework of long-term monitoring (2011–2022) in Báránd, Hungary, using water quality indices and GIS (Geographic Information System) techniques. In order to understand the purification processes and spatial and temporal changes, three periods were determined: the pre-sewerage period (2011–2014), the transitional period (2015–2018), and the post-sewerage period (2019–2022). Forty monitoring wells were included in the study, ensuring complete coverage of the municipality. The results revealed a high level of pollution in the area in the pre-sewerage period. Based on the calculated indices, an average of 80% of the wells were ranked in categories 4–5, indicating poor water quality, while less than 8% were classified in categories 1–2, indicating good water quality. No significant purification process was detected in the transitional period. However, marked changes were observed in the post-sewerage period as a result of the elimination of local sources of pollution. In the post-sewerage period, the number of monitoring wells ranked as excellent and good increased significantly. Additionally, the number of wells assigned to category 5 decreased markedly, compared to the reference period. The significant difference between the three periods was confirmed by the Wilcoxon test as well (p &lt; 0.05). Based on interpolated maps, it was found that, in the post-sewerage period, an increasing section of the settlement had good or excellent water quality. In addition to an assessment of long-term tendencies, the annual fluctuations in the water quality of the wells were also examined. This showed that the purification processes do not occur in a linear pattern but are influenced by various factors (e.g., precipitation). Our results highlight the importance of protecting and improving groundwater resources in municipal areas and the relevance of long-term monitoring of water adequate management policy.

Microbiological quality of drinking water from three flood-prone communities along the Odaw River in Accra, Ghana

ABSTRACT Access to safe drinking water is considered a fundamental human right, yet, in most developing countries, this is not the case, as microbial contamination of drinking water is commonly responsible for the transmission of many waterborne diseases, including cholera, typhoid fever, diarrhoea, and dysentery. The study aimed to assess the microbiological quality of drinking water from three communities along the Odaw River in Accra, known for their poor waste disposal practices and incidents of flooding. Water samples were collected from community tap water and locally manufactured sachet water from three flood-prone communities along the Odaw River, namely, Alajo, Avenor, and Agbogbloshie, and analyzed for the presence of indicator organisms: total coliforms, faecal coliforms, and Escherichia coli (E. coli). All brands of sachet water sampled from the three communities had no microbial contamination. Conversely, most community tap water showed contamination with indicator organisms that exceeded the international standard of 0 per 100 mL for potable water. The presence of faecal coliforms and E. coli in community shared tap water is an indication of poor water quality and may present a risk for waterborne disease outbreaks among households and communities.

Geoenvironmental determinants influencing chronic kidney disease of unknown etiology in the dry zone of Sri Lanka: a study based on a cohort of at-risk communities.

Chronic kidney disease of unknown origin (CKDu) has emerged as a serious health risk for farming communities in remote semi-arid lowland regions of Sri Lanka, with geoenvironmental factors widely believed to be associated with the etiology. Although numerous case-control studies have been carried out to determine the causes of CKDu, none have been conducted in at-risk communities. The main objective of this study is to identify the potential geo-environmental risk factors associated with the at-risk community in the Wilgamuwa region, a CKDu endemic area in Sri Lanka. The study collected and analyzed 92 water sources currently or previously used in the study area for major cations, anions, and trace elements, mainly As, Cd, Pd, Mn, Zn, Ba and Sr. The major cations and anions in CKDu-susceptible groundwater varied Si4+ > Ca2+ > Na+ > Mg2+ > K+ and HCO3- > Cl- > SO42- > NO3- > F- > PO43- > Br-. The higher average values of Si4+, F- and total hardness (TH) were reported in groundwater consumed by communities at risk of CKDu, with average values (in mg/L) of Si4+-46, F--0.62, and TH-178. Considering the Water Quality Index (WQI) values, 73% of groundwater sources are classified as poor water quality, and the groundwater quality mainly depends on the fluoride distribution in the region. According to the Hazard Quotient (HQ), the risk of adverse health effects from exposure to F- and SiO2 increased in magnitude in the order of male < female < children. Health hazards due to As, Cd and Pb exposure fell between the 'no-risk' and 'low-risk' categories. As outlined in this study, continuous monitoring of vulnerable communities for environmental exposures to key groundwater constituents is important in the dry zone of Sri Lanka.

Prolonged alkali water irrigation: impacts of treatment strategies on soil health and microbial dynamics

BackgroundThe extent of natural salt-laden groundwaters used for irrigation is increasing worldwide, which is a fast-emerging threat to agroecosystems and global food security. The salt buildup in the soil is linked to deteriorated soil chemical, physical, and biological health and decreased land productivity. Alkali waters with high residual sodium carbonate (RSC) is one of the severe poor-quality waters that deteriorate soil. We evaluated soil microbial dynamics and soil health at critical growth stages of rice crop receiving two-decade-long irrigation with three levels of alkali water and two reclamation strategies. These included good-quality water (GQW), alkali water (ALKW) with an RSC concentration of 5 me L⁻1 (ALKW1), ALKW with an RSC concentration of 10 me L⁻1 (ALKW2), ALKW2 treated to neutralize RSC to 5 me L⁻1 using gypsum (CaSO4·2H2O; ALKW2 + GYP), and ALKW2 treated with sulfuric acid (H2SO4; ALKW2 + SA). Eleven microbial parameters were used to develop a soil microbial activity index (SMAI), and eight soil health indicators were correlated with changes in SMAI and crop productivity.ResultsThe SMAI peaked under good-quality water (GQW) conditions (0.84–0.89), while the lowest values were recorded under ALKW2 (0.06–0.18). Neutralized alkali waters, ALKW2 + SA and ALKW2 + GYP, significantly improved SMAI with corresponding values of 0.25–0.35 and 0.13–0.32, respectively. SMAI across all stages correlated positively (R2 = 0.91–0.98) with rice yield. Microbial activity varied with the crop growth stage, peaking at tillering. Gypsum application alone, aimed at neutralizing alkalinity from an RSC of 10 to 5 me L⁻1, proved insufficient in bringing the SMAI up to the ALKW1 (RSC level of 5 me L⁻1).ConclusionsThe application of dilute sulfuric acid demonstrated better results in restoring the soil microbial activity index than gypsum amendment; however, sulfuric acid treatment depends on native calcium carbonate (CaCO3) dissolution for its effectiveness. It may not suffice for soil stability improvement in the long term, especially when native CaCO3 is low. Therefore, integrating gypsum and dilute sulfuric acid for RSC neutralization is worthwhile; however, further assessment is needed to confirm their combined impact on soil biochemical and physical properties.

Surface water quality in Costa Rica: new initiatives and challenges

ABSTRACT Despite Costa Rica's reputation for being a leader in environmental policy and its thriving nature-based tourism industry, the nation has had poor surface water quality. Reasons for poor water quality include the lack of sewerage treatment, overuse of septic tanks, and the application of large quantities of agrichemicals. Although Costa Rica has policies to maintain surface water quality, they have not been sufficiently implemented. Recent initiatives have addressed surface water quality, including an ambitious plan to expand treated sewerage systems in all urban areas. Current efforts to meet this goal have focused on the San Jose metropolitan area and coastal communities. This paper reviews the advances and challenges to Costa Rica's efforts to improve water quality.

Application of lactic acid bacteria to improve the food safety of sago starch

Sago starch production in local industries is still carried out traditionally and uses poor-quality water. This production causes sago starch to be fermented spontaneously, resulting in sour sago and possibly contamination by pathogenic bacteria. Lactic acid bacteria (LAB) can produce lactic acid and are suitable for use as a starter. Adding LAB as a starter in sago starch fermentation is expected to reduce the number of pathogenic bacterial growths, thereby increasing food safety in sago starch. This research aimed to obtain LAB and evaluate their use in sago starch fermentation to improve food safety. LAB selection was conducted by testing the LAB tolerance ability to low pH and the adaptability of the LAB growth in sago starch. This study was carried out using and without a LAB liquid starter. The water source during the fermentation originated from drinking water and the sago starch industrial factory. The fermentation was carried out for ten days at room temperature with an observation every two days. The results showed that fermented sago starch using drinking water did not harbor E. coli, Salmonella, or Shigella bacterial contamination. In contrast, sago starch fermented using water from the factory harbored these bacterial contaminations. Adding LAB IL1 isolate as a starter in fermentation showed the ability to reduce the number of pathogenic bacteria in sago starch.