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Exploration of the pollution status of river-based water sources is important to ensure quality and safe drinking water supply for the public. The present study investigated physicochemical parameters of surface water in the upper segment of River Mahaweli, which provides drinking water to the Nuwara Eliya and Kandy districts of Sri Lanka. River surface water from 15 intakes and treated water from 14 Water Treatment Plants (WTPs) were tested for pH, water temperature, turbidity, EC, COD, 6 anions, 21 cations, 3 pesticides, and 30 antibiotics once every 3 months from June 2022 to July 2023. Except for turbidity and iron concentrations, all other parameters were within the permissible range as per the Sri Lanka Standard Specification for Potable Water (SLS 614:2013). The uppermost Kotagala WTP raw water had a high concentration of iron due to runoff from areas with abundant iron-bearing minerals. Turbidity increased as the river flowed downstream, reaching its highest value of 13.43 NTU at the lowermost Haragama. Four intakes had raw surface water suitable for drinking as per the Water Quality Index (WQI). Pollution increased gradually towards downstream mainly due to agricultural runoff, industrial effluents, and urbanization. Poor water quality at the upstream Thalawakale-Nanuoya intake was due to highly contaminated effluent water coming from Lake Gregory in Nuwara Eliya. Cluster analysis categorized WTP locations in the river segment into 3 clusters as low, moderate, and high based on contaminations. Principal component analysis revealed that the significance of the 41.56% variance of the raw water was due to the pH and the presence of heavy metals V, Cr, Ni, Rb, Co, Sr, and As. All treated water from 15 WTPs had very good to excellent quality. In general, heavy metal contamination was low as indicated by the heavy metal pollution index (HPI) and heavy metal evaluation index (HEI). The treatment process could remove up to 94.7% of the turbidity. This is the first attempt to cluster the river catchment of the Mahaweli River based on physicochemical parameters of river water. We present here the land-use pattern-based pollution of the river and efficacy of the water treatment process using the Mahaweli River Basin as a case study. Regular monitoring and treatment adjustments at identified points are recommended to maintain the delivery of safe drinking water. [ABSTRACT FROM AUTHOR]

Understanding the influence of long-term crop management practices on the soil microbial community is critical for linking soil microbial flora with ecosystem processes such as those involved in soil carbon cycling. In this study, pyrosequencing and a functional gene array (GeoChip 4.0) were used to investigate the shifts in microbial composition and functional gene structure in a medium clay soil subjected to various cropping regimes. Pyrosequencing analysis showed that the community structure (β-diversity) for bacteria and fungi was significantly impacted among different cropping treatments. Functional gene array-based analysis revealed that crop rotation practices changed the structure and abundance of genes involved in C degradation. Significant correlations were observed between the activities of four enzymes involved in soil C degradation and the abundance of genes responsible for the production of respective enzymes, suggesting that a shift in the microbial community may influence soil C dynamics. We further integrated physical, chemical, and molecular techniques (qPCR) to assess relationships between soil C, microbial derived enzymes and soil bacterial community structure at the soil micro-environmental scale (e.g. within different aggregate-size fractions). We observed a dominance of different bacterial phyla within soil microenvironments which was correlated with the amount of C in the soil aggregates suggesting that each aggregate represents a different ecological niche for microbial colonization. Significant effects of aggregate size were found for the activity of enzymes involved in C degradation suggesting that aggregate size distribution influenced C availability. The influence of cropping regimes on microbial and soil C responses declined with decreasing size of soil aggregates and especially with silt and clay micro-aggregates. Our results suggest that long term crop management practices influence the structural and functional potential of soil microbial communities and the impact of crop rotations on soil C turnover varies between different sized soil aggregates. These findings provide a strong framework to determine the impact of management practices on soil C and soil health.

In recent decades, the consumption of tea has increased due to its various associated health benefits, prompting growing concerns regarding the safety and quality of tea products. Nevertheless, there has been a significant dearth of scientific information regarding the microbiological status of black tea leaves. This study sought to bridge this knowledge gap by investigating the microflora present in tea leaves at various processing stages of black tea production. Samples were meticulously collected during distinct processing steps, and their culturable microorganisms were identified through sequence‐based methods. The results revealed that the predominant bacterial genus throughout the tea manufacturing process was Bacillus, constituting a substantial 77% of the identified bacterial population. Other leading genera included Klebsiella (8%), Lysinibacillus (4%), Escherichia (2%) with the remaining 9% comprising various other genera. Among the fungal community, Aspergillus and Penicillium species exhibited a significantly higher relative abundance, each comprising 24%. Furthermore, yeast communities included Debaryomyces, Candida, Hyphopichia, Rhodosporidiobolus, and Wickerhamomyces species. Lactobacillus fermentum was identified in the fermented tea leaves, highlighting its role in the fermentation process. Yeasts and molds were also present in the final tea product, indicating potential post‐processing contamination. The study did not detect any mycotoxins in any of the samples. These findings had indicated that presence of some microorganisms is extremely common in different processing stages while alien microorganisms are being introduced during manufacturing. Thus, emphasizing the need for stringent regulations and quality assurance practices within the tea industry to ensure the safety and quality. [ABSTRACT FROM AUTHOR]

Cryptosporidium is a protozoan parasite that causes gastroenteritis in both humans and animals. Cryptosporidium infections in humans and animals have been reported from many parts of Sri Lanka. During the present study, five international electronic databases were extensively searched for peer-reviewed research papers published on the prevalence of Cryptosporidium infections and their occurrence in probable sources in Sri Lanka, within the time frame from 1987 to 2023. Collected information revealed that Cryptosporidium oocysts are more commonly found in surface water compared to well water, and shallow wells have a higher occurrence than deep wells. Contamination of river water with Cryptosporidium is mainly from the faecal matter coming from various domestic, agricultural and wildlife animal species. In Sri Lanka, Cryptosporidium infections in captive non-human primates is possibly due to contaminated food and human interaction. In wild animals, infections are more common in species that feed on the ground, suggesting contaminated soil and water as the source of infection. Most of the infected animals are asymptomatic, and many had co-infections with other enteric parasites. Molecular analysis of Cryptosporidium samples from infected primates revealed the presence of four major clades of C. parvum, with some isolates closely related to zoonotic C. parvum genotypes. Information on the habitats of the infected primates suggests that livestock is the primary source of infection. Several studies have been conducted to investigate the prevalence of Cryptosporidium infection in various livestock animals, particularly in goats, cattle, buffaloes, and swine in Sri Lanka. These studies reveal high prevalence of asymptomatic Cryptosporidium infection in goats and the potential for the transmission of zoonotic C. parvum from goats, cattle and buffaloes to humans. Molecular epidemiological analysis identified new genotypes of Cryptosporidium in domestic bovids (cattle and water buffalo), with no evidence of the commonly reported zoonotic species C. parvum. Waterborne transmission is the most common mode of infection of Cryptosporidium that affect both humans and animals. Studies conducted in human populations are primarily based in hospitals and pre-schools, and conclude that Cryptosporidium infections are a common cause of diarrhoea in children under the age of five. In conclusion, Cryptosporidium infections occur in different species of animals and humans in Sri Lanka and the oocysts have been detected in surface water, which might be an important source of infection for animals and humans in the country. [ABSTRACT FROM AUTHOR]

Agriculture is heavily climate dependent. Tea cultivation is of no exception. Tea is cultivated in many developing nations around the globe and the climate change impact is to be mostly felt by developing nations in comparison to the developed. In countries such as Sri Lanka, where the major portion of export earning from agriculture comes from the tea industry, the climate change impacts would harm its progress. Hence, understanding how climate has been linked with production would pave the way for development of a country specific policy. To this end, this research attempted to measure the long-run relationship of the climate with the yield per hectare, using monthly data from 2005 to 2019. A panel Autoregressive Distributed Lag model (ARDL) was used to obtain long-run cointegration between minimum and maximum temperatures and the amount of rainfall received. Data on production and input variables were obtained from records kept at 37 largescale tea estates at monthly intervals. Monthly temperature and rainfall data were obtained from the Meteorological Department of Sri Lanka. Panel cointegration tests indicated that there is a coexisting long-run relationship between climate variables and the tea yield. Maximum temperature had a positive relationship with yield, but minimum temperature shows a long-run negative relationship. Rainfall is positively related. Production inputs show a long-run positive impact. Thus, the possible negative impacts of rising minimum temperature could be overcome if proper management practices are adopted in the long-run. [ABSTRACT FROM AUTHOR]

Elimination of vector mosquito larvae and their breeding environments is an effective strategy in dengue disease control. Present study examined larval density and water quality in breeding habitats and container preference of dengue vectors Ae. aegypti and Ae. albopictus. Larval surveys were conducted monthly in urban, semiurban, and rural sites in Kurunegala, Sri Lanka, from January 2019 to December 2021. Larval densities were recorded under the following three categories: type of container (16 types), type of material (6 types), and location (indoor/outdoor). Breeding preference ratios (BPRs) were calculated using Index of Available Containers and the Index of Contribution to Breeding Sites. Out of 19,234 wet containers examined, larval stages were found in 1,043 habitats. Ae. albopictus larvae were in all three areas whereas Ae. aegypti larvae were restricted to urban areas. Highest number of wet containers and highest positivity were reported from urban followed by semiurban. In general, discarded nondegradable items were the most frequent and mostly positive breeding sites. For Ae. aegypti, the most preferred breeding sites were gutters and concrete slabs. Ae. albopictus mostly preferred concrete slabs in urban areas and tyres in semiurban and rural areas. Material types such as rubber and concrete were mostly preferred by Ae. aegypti whereas ceramic was preferred by Ae. albopictus. Although plastic was the most available material type in all study sites, preference to plastic was low except for urban Ae. albopictus. Both species preferred urban indoor breeding habitats although outdoor breeding was preferred by Ae. albopictus in rural areas. Larval densities of Ae. aegypti and semiurban Ae. albopictus significantly correlated with the BPR of the container type and material type. Dengue vector larvae were found in a 6.7–9.4 pH range. Total dissolved solids and alkalinity positively correlated with preference. Information generated can be successfully used in waste management and public education for effective vector control. [ABSTRACT FROM AUTHOR]