Waterborne disease-related risk perceptions in the Sonora River basin, Mexico

Evolution of waterborne diseases: A case study of Khyber Pakhtunkhwa, Pakistan

Objectives

In Pakistan, the degradation of drinking water quality is exacerbated by the increasing population size and rapid industrialization. Contaminated water serves as the predominant source of numerous diseases, including diarrhea, gastroenteritis, and typhoid. This article explores the evolution of waterborne diseases across 21 districts of the Khyber Pakhtunkhwa province in Pakistan by monitoring changes in the clustering solutions.

Methods

The data employed in this study were sourced from 21 districts of KP by the Director-General Health Services. Cluster analysis was utilized to uncover patterns in waterborne disease incidence, while principal component analysis was employed to reveal underlying patterns and reduce dimensionality. Additionally, the MONItoring Clusters (MONIC) framework was applied for change detection, facilitating the identification of significant shifts in disease patterns over time and aiding in the understanding of temporal dynamics.

Results

Our analysis indicates that two clusters survived consistently over time, while other clusters exhibited inconsistency. Profiling of the surviving clusters (C12 → C24 → C32 → C43) suggests a gradual increase in cases of bloody diarrhea in the Swat Valley, Hangu, Karak, and Lakki Marwat regions. Similarly, profiling of the surviving clusters (⊙→ C22 → C34 → C44) suggests an increase in the acute watery diarrhea (non-cholera) and typhoid fever in the regions of Peshawar, Nowshera, and Swabi.

Conclusion

The findings of this study hold significant importance as they pinpoint the most vulnerable regions for various waterborne diseases. These insights offer valuable guidance to policymakers and health officials, empowering them to implement effective measures for controlling waterborne diseases in the respective regions of Khyber Pakhtunkhwa, Pakistan.

Acid spill impact on Sonora River basin. Part I. sediments: Affected area, pollutant geochemistry and health aspects

The Sonora River and its tributary streams (Tinajas, Bacanuchi) were impacted in 2014 by an acid solution spill (approximately 40,000 m³). This study aims to presents a clear and supported overview to determining the spill's consequences on the environment and the people inhabiting the area. The elements quantified were those found in the spilled solution: Al, As, Cu, Fe, Mn, Pb, and Zn. Potential Toxic Element (PTE) concentration means from 187 sediment samples were, in mg.kg^-1: Al = 7,307, As = 16.6, Ba = 128 Cu = 106 Fe = 15,764, Mn = 566, Pb = 46 and Zn = 99. Differences between PTE concentrations in the most impacted sediments and those of the local baseline, sampled in streams not affected by the spill and regional baseline values, were not statistically significant. The similarity of PTE concentrations among sediments may be explained by natural geological enrichment, historical mining impacts, and a low increase of PTE in sediments after the acid spill because of natural and anthropogenic attenuation. Mainly heavy rains, natural pedogenic carbonates, and remedial work done by the mining company (retaining dam, adding lime; precipitation, collecting formed solids, and transport to the mine). The Contamination Factor (C.F.), Enrichment Factor (E.F.), and Geo-accumulation Index (Igeo) were determined. The C.F. indicated low and moderate contamination in all elements. Cu exhibited the highest E.F., from moderate to significant enrichment. The Igeo generally ranged from -0.02 to 0.15. Cu and Zn were classified as moderately to heavily contaminated. In local baseline sediments, the Cu C.F. varied from moderate to very high contamination, the Cu E.F. from moderate to significant enrichment, while the As, and Pb Igeo ranged from uncontaminated to moderately contaminated. In general, normalization demonstrated a high degree of Cu enrichment at sites 1-14. Sequential extractions indicated that only Cu was found in all fractions, including a significant exchangeable fraction in the very impacted sediments (1-14). The other PTEs were distributed between the Fe/Mn oxide fraction and the residual phase. Principal Components Analysis for PTE concentrations indicated three different groups with similar geochemical patterns and allowing to identify the PTE potentially sources: the first sediments from sites 1-14 were the impacted sediments in accordance with pH and electrical conductivity results, the second group from sites 15-20 showed characteristics of the mineralized environment, and the third from sites 21-30 were unrelated to the spillage. The area impacted by the acid solution spill reached approximately 30 km downstream, just roughly 15% of the initially considered area.

Population awareness and attitudes toward waste-related health risks in Accra, Ghana

Despite significant knowledge about the potential health hazards of waste, there are few studies in African cities that investigate awareness of health issues related to waste management, although such research is needed to lower population exposure. This paper examines the case study of Accra in Ghana, a city dealing with serious health and pollution problems. Three focus groups and 157 households in Accra were surveyed on household waste disposal and awareness of waste-related health hazards. Surveyed households had limited knowledge of waste-related health hazards in their neighbourhoods. Although the households reported diseases that could be associated with environmental factors linked to waste management, 87% of all surveyed households did not think that someone in their household could have fallen ill of a disease that can be related to waste. In middle- and high-income neighbourhoods, waste burning increases substantially when waste is not collected.

Rapid water disinfection over a Ag/AgBr/covalent triazine-based framework composite under visible light

An Ag/AgBr/covalent triazine-based framework composite was successfully utilized for the rapid photocatalytic inactivation of bacteria under visible light.

Dengue Disease Risk Mental Models in the City of Dhaka, Bangladesh: Juxtapositions and Gaps Between the Public and Experts

Worldwide, more than 50 million cases of dengue fever are reported every year in at least 124 countries, and it is estimated that approximately 2.5 billion people are at risk for dengue infection. In Bangladesh, the recurrence of dengue has become a growing public health threat. Notably, knowledge and perceptions of dengue disease risk, particularly among the public, are not well understood. Recognizing the importance of assessing risk perception, we adopted a comparative approach to examine a generic methodology to assess diverse sets of beliefs related to dengue disease risk. Our study mapped existing knowledge structures regarding the risk associated with dengue virus, its vector (Aedes mosquitoes), water container use, and human activities in the city of Dhaka, Bangladesh. "Public mental models" were developed from interviews and focus group discussions with diverse community groups; "expert mental models" were formulated based on open-ended discussions with experts in the pertinent fields. A comparative assessment of the public's and experts' knowledge and perception of dengue disease risk has revealed significant gaps in the perception of: (a) disease risk indicators and measurements; (b) disease severity; (c) control of disease spread; and (d) the institutions responsible for intervention. This assessment further identifies misconceptions in public perception regarding: (a) causes of dengue disease; (b) dengue disease symptoms; (c) dengue disease severity; (d) dengue vector ecology; and (e) dengue disease transmission. Based on these results, recommendations are put forward for improving communication of dengue risk and practicing local community engagement and knowledge enhancement in Bangladesh.

[Risk of contamination from exposure to Rio Doce water: a case study on the population's perceptions in Tumiritinga, Minas Gerais State, Brazil]

The close relationship between local residents and the Rio Doce and the river's recurrent flooding lead to continuous exposure of the population to waterborne diseases. Given the epidemiological importance of such diseases in the region, this study analyzes the association between risk perception of contamination and river water use, as well as the heuristic mechanisms used by individuals to shape their personal perception of risk. Regression models coupled with thematic network analysis were applied to primary data from 352 households in 2012. The data are representative of urban residents of Tumiritinga, Minas Gerais State, Brazil. The results show that while 92.6% of respondents perceived high risk of waterborne diseases, only 11.4% reported not making direct use of the river. This apparent paradox is explained by the lack of information on transmission mechanisms, underestimating the perception of contamination. Public campaigns to promote preventive behavior should stress how waterborne diseases are transmitted, using simple examples to reach a wider local audience.

Modeling riverine pathogen fate and transport in Mexican rural communities and associated public health implications

The discharge of untreated or poorly treated wastewater to river systems remains a major problem affecting public and environmental health, particularly in rural communities of less developed countries. One of the primary goals in setting policies for wastewater management is to reduce risks to human health associated with microbial contamination of receiving water. In this study, we apply a surface water quality model to develop an Escherichia coli based indicator that reflects the quality of surface water and the potential impact to recreational users in a large, rural river in northwest Mexico (upper Sonora River). The model assesses the relative importance of streamflow variations and the uncertainty in E. coli removal coefficient parameters for the predictions of E. coli concentrations in the river. Given the sparse information on streamflow, we use a physically-based, distributed hydrologic model to generate tributary contributions to the river. We determined the best estimate and uncertainty of E. coli removal rates to explore the impacts of parameter uncertainty on the transport of E. coli downstream from two wastewater discharge zones. Our results depict the regions in the river that are in noncompliance with fresh water pathogen norms. The impact of streamflow variability and uncertainty in the removal rates of pathogen indicators was used to derive a range of river distances in noncompliance. The comparison between two sites with different streamflow behaviors was used to illustrate the impacts of streamflow spatiotemporal variability on pathogen indicators. We derive a simple relationship that can be used to assess the relative importance of dilution (ratio of wastewater discharge to river discharge) and pathogen removal (ratio of residence time to reaction time).

Socio-Environmental Health Analysis in Nogales, Sonora, Mexico

In Nogales, Sonora, Mexico, some neighborhoods, or colonias, have intermittent delivery of water through pipes from the city of Nogales’s municipal water-delivery system while other areas lack piped water and rely on water delivered by truck or pipas. This research examined how lifestyles, water quality, and potential disease response, such as diarrhea, differs seasonally from a colonia with access to piped water as opposed to one using alternative water-delivery systems. Water samples were collected from taps or spigots at homes in two Nogales colonias. One colonia reflected high socio-environmental conditions where residents are supplied with municipal piped water (Colonia Lomas de Fatima); the second colonia reflected low socio-environmental conditions, lacking access to piped water and served by pipas (Colonia Luis Donaldo Colosio). A survey was developed and implemented to characterize perceptions of water quality, health impacts, and quality of life. Water samples were analyzed for microbial and inorganic water-quality parameters known to impact human health including, Escherichia coli (E. coli), total coliform bacteria, arsenic, and lead. A total of 21 households agreed to participate in the study (14 in Colosio and 7 in Fatima). In both colonias metal concentrations from water samples were all well below the United States Environmental Protection Agency’s (US EPA’s) maximum contaminant levels. E. coli concentrations exceeded the US EPA’s drinking-water standard in Colosio but not Fatima. Total coliform bacteria were present in over 50 % of households in both colonias. Microbial contamination was significantly higher in the summer than in the winter in both colonias. Resulting analysis suggests that residents in colonias without piped water are at a greater risk of gastrointestinal illness from consumption of compromised drinking water. Our survey corroborated reports of gastrointestinal illness in the summer months but not in the winter. Chloride was found to be significantly greater in Colosio (median 29.2 mg/L) although still below the US EPA’s maximum contaminant levels of 250 mg/L. Ongoing binational collaboration can promote mechanisms to improve water quality in cities located in the US–Mexico border.