Drainage Canals Research Articles

МІНЕРАЛЬНИЙ СКЛАД, ГЕОХІМІЧНІ ОСОБЛИВОСТІ І ВПЛИВ НА ДОВКІЛЛЯ ВІДВАЛУ ФОСФОГІПСУ НОВОРОЗДІЛЬСЬКОГО ЗАВОДУ СКЛАДНИХ МІНЕРАЛЬНИХ ДОБРИВ (ЛЬВІВСЬКА ОБЛ.)

Phosphogypsum of Novorozdilsky Plant of Complex Mineral Fertilizers (Lviv region) is a typical artificial neogenic mineral formation, solid waste by-product generated when sulphuric acid reacts with the phosphorus-containing ores (apatite or phosphorite concentrates) during manufacturing of phosphoric acid. The raw materials for fertilizer production at the plant were sulphuric acid, which was obtained from the sulphur ores of Rozdilske SMCE “Sirka”, apatite concentrate from the Khibiny deposit (Kola Peninsula) and, to a lesser extent, phosphorite concentrate from sedimentary phosphorites. The plant has not been operating since 1995, but 4.5 million tons of phosphogypsum and also acidic mineralized water in the settling lake have accumulated on its territory since then. Gypsum (85–95 %) and bassanite (5–10 %) dominate in the mineral composition of phosphogypsum, there are also undissolved apatite (up to 2–3 %) and trace amounts of minerals that were originally in apatite concentrate (quartz, nepheline, pyroxene, aegirine, feldspar, biotite, etc.). The surface of the phosphogypsum heap is a phytophilous man-made substrate that is actively overgrown with woody vegetation. This is due to the filtration properties of phosphogypsum Василь Дяків, Ельвіра Джумеля, Мирослав Ковальчук та ін. 106 ISSN 2078-6220. Мінералогічний збірник. 2022. № 72 (they promote water accumulation and leaching of phytotoxic compounds from the zone of active water exchange) and the presence of a significant amount of phosphates. Currently, a dense aspen-sea buckthorn forest grows on the slopes of the dump. Acidic infiltrates are formed in the process of infiltration of precipitation through the thickness of the phosphogypsum dump, they are accumulated in the settling lake (Central/Acid Lake). In terms of chemical composition, it is sulphate-phosphate sodium-magnesium-calcium water with high fluorine content and mineralization of 2931.6 mg/dm3. The cessation of the use of the lake (as a settling tank for the plant's circulating waters) and the constant accumulation of infiltrate have led to a number of environmental problems. Acidic infiltrates flow into the mine canal and significantly impair the quality of water in it. Only due to the dilution of infiltrates with clean water of the drainage channel (with a flow rate of three to four times higher) before flowing into the transboundary Dniester River hydrochemical composition of water meets the normative values of salt composition and content of major pollutants. Deterioration of the water quality of the mine canal and, as a consequence, pollution of the Dniester in case of prolonged drought or reduction of the debit of the drainage canal are envisaged. To minimize the negative impact of the phosphogypsum dump on the environment, a project to build a cascade of filter dams from local carbonate materials has been proposed. Limestones have the ability to neutralize acidic waters; they are highly permeable and contain sulphur, which causes the binding of heavy metals to insoluble compounds. Due to the interaction of carbonates with acidic infiltrates, water-insoluble calcium phosphates and calcium fluoride (fluorite) are formed, which helps to purify water from F and P, and newly formed hydrates reduce the moisture content of the phosphogypsum mixture with flotation tails. The proposed approach will make it possible to control a constant source of pollution and restore the ecological balance disturbed by economic activities

Coexistence of Lobelia dortmanna and Cladium mariscus, an ecological and paleobotanical study

Lobelia dortmanna L. (Lobeliaceae family) is an indicator species that is predominantly found in oligotrophic and acidic lakes. They are mainly distributed in northwestern Europe. Their occurrence in Poland is highly threatened by the increasing grade of human activity and environmental eutrophication; however, new sites of Lobelia were discovered in the last few decades, for example, in Lake Krzywce Wielkie situated in Bory Tucholskie National Park (BTNP), Poland. The existence of Lobelia in this lake was unexpected because Cladium mariscus was also found in the lake. Cladium has different ecological demands and is regarded as a species typical of calcareous habitats where calcium is found in abundance in the substrate. To explain the coexistence of both species in Krzywce Wielkie, pollen analysis of organic sediments was performed for four short cores collected from the littoral zone of the lake and for one long deep-water core. Additionally, macrofossil analysis was done for all the short cores. Pollen analysis revealed the existence of Cladium from the early Holocene period up to the present time. Pollen and seeds of Lobelia were found to be present since the beginning of the 20th century. Development of L. dortmanna and Myriophyllum alterniflorum populations and a decrease in the number of aquatic macrophytes in the eutrophic water indicate oligotrophication of water. This process started following the construction of drainage canal and the consequent water level decrease. This situation can be attributed to the abandonment of the agricultural areas adjoining the lake, which causes a decrease in the inflow of nutrients into the lake. Development of pine forest and establishment of BTNP enabled the protection and conservation of the surrounding catchment areas, thus restricting the potential eutrophication of the habitats.

Morphology Detection in Archaeological Ancient Sites by Using UAVs/Drones Data and GIS techniques

Today, Unmanned Aerial Vehicles (UAVs) or Drones are a valuable source of data on inspection, surveillance, mapping and 3D modelling matters. Drones can be considered as the new alternative of classic manned aerial photography due to their low cost and high spatial resolution. In this study, drones were used to study archaeological sites. The archaeological Nineveh site, which is a very famous site located in heart of the city of Mosul, in northern Iraq, was chosen. This site was the largest capital of the Assyrian Empire 3000 years ago. The site contains an external wall that includes many gates, most of which were destroyed when Daesh occupied the city in 2014. The local population of the city of Mosul has also largely overtaken the central part of this archaeological site, while the northern and southern parts are still uninhabited. The awareness of the existence of unchanged surface and ground forms in the northern or southern parts led us to prepare an urgent study to interpret the outer surface of those parts and to analyze any discovery in the surface morphology. So, drone data and GIS technologies were used in this study to find any discovery that could aid in understanding the original surface of this ancient site. Visual and digital interpretations of satellite images, drone images, and Digital Surface Models (DSMs) were used to analyze and study the data. As a final result, certain morphological features were identified in the southern parts of the ancient site which could be a new archaeological and compositional discovery with reference to the earlier activities of the ancient society during the Assyrian empires, represented by the ditches and building lands used by the ancient inhabitants. Small modern tunnels penetrated the ancient wall were also discovered in addition, to a drainage canal and a motorway newly constructed during the occupation of the city that had penetrated the archaeological land.

Evaluation of the use of prepaid water meter on some irrigation management performance indicators: A case study

Volume based pricing in irrigation is an important application method in solving excessive and illegal water use problems. It is essential to use a properly selected water meter to accurately measure the amount of water. In this study, the irrigation system performance of Kayack Water User Association (WUA) was comparatively analyzed for the years 2012 to 2017. The prepaid water meter has been used for water measurement in Kayacık irrigation scheme since 2015. While it could be irrigated on 11.754 ha in 2012, the irrigated area reached 19.528 ha in 2017. It was determined that there was a significant water saving and economic recovery after the installation of prepaid water meters in the irrigation scheme. The quantity of water, which was 7,414 m3ha-1 in 2012, decreased to 3,617 m3ha-1 in 2017. The cost recovery ratios were 76% and 107% in 2013 and 2017, respectively. Consequently, prepaid water meter usage provides so many advantages in service delivery, economics and productivity. In addition, the quantity of water discharged into the drainage canal has significantly decreased. It is recommended that prepaid water meter usage should be prevalence in irrigation operation.

Trypsin dose optimization for glaucoma induction in rabbit model

Glaucoma is a neurodegenerative disease identified by optic nerve damage and loss of retinal ganglionic cells. The aim of the study was to test the precise dose of trypsin to induce glaucoma in a rabbit model. Nine White New Zealand rabbits were randomly divided into three groups: Group one (G1) normal animals as control, group two (G2) the animals were injected with 0.2 ml of 0.04% trypsin and group three (G3) injected with 0.2 ml of 0.05% trypsin into posterior chamber of eye. A schiotz tonometer was used to measure intraocular pressure (IOP) before the injection, two days after injection and once a week until the end of the second week. At the end of the second week, the histology of the retina and optic nerve was studied. G3's intraocular pressure increased by 43.7%, while G2's intraocular pressure increased by 0.7% compared to G1. Retinal ganglionic cells (RGCs) decreased in G3 by 91.5% and G2 by 43.8% in comparison with G1. Optic nerve histology in G3 displayed decreased Schwann cell quantity with vacuolation and low orientation of nerve fibers compared with G1 and G2. Group three had the highest increase in IOP due to obstruction of drainage canal and preventing outflow of aqueous humor. This resulted in mechanical compression on the retina, ending with loss of RGC and degeneration of the optic nerve. The conclusion is that 0.2ml of 0.05% trypsin is the proper dose for the induction of glaucoma.

Observations of a Nuclear–follower Foraging Association between Spiny Softshell Turtles (Apalone spinifera) and Fish in an Urban Drainage Canal in Louisiana

The nuclear–follower relationship is a specialized interspecific foraging association in which the nuclear species excavates the substrate while foraging, and follower species access food items flushed or uncovered by the nuclear species. We observed a nuclear–follower association between Apalone spinifera (Spiny Softshell Turtle) and fish (Micropterus salmoides [Largemouth Bass] and Lepomis spp.) in an urban drainage canal (Wards Creek) in Baton Rouge, LA, during June and July of 2020. Groups of Largemouth Bass and Lepomis spp. numbering 0–2 and 1–20, respectively, followed foraging Spiny Softshell Turtles. When foraging, Spiny Softshell Turtles were observed moving along the creek bottom, thrusting their probosces into and vigorously excavating the substrate. The accompanying fish then entered the cloud of suspended sediment to pursue and capture prey. Excavation of the substrate by Spiny Softshell Turtles appears to be the critical component of this nuclear–follower relationship, flushing or exposing prey that would otherwise be unavailable to fish. This nuclear–follower relationship is apparently one of commensalism, i.e., while fish probably benefit from increased foraging success, few if any benefits accrue to foraging turtles.

Identifying Key Drivers of Peatland Fires Across Kalimantan's Ex-Mega Rice Project Using Machine Learning.

Throughout Indonesia ecological degradation, agricultural expansion, and the digging of drainage canals has compromised the integrity and functioning of peatland forests. Fragmented landscapes of scrubland, cultivation, degraded forest, and newly established plantations are then susceptible to extensive fires that recur each year. However, a comprehensive understanding of all the drivers of fire distribution and the conditions of initiation is still absent. Here we show the first analysis in the region that encompasses a wide range of driving factors within a single model that captures the inter‐annual variation, as well as the spatial distribution of peatland fires. We developed a fire susceptibility model using machine learning (XGBoost random forest) that characterizes the relationships between key predictor variables and the distribution of historic fire locations. We then determined the relative importance of each predictor variable in controlling the initiation and spread of fires. The model included land‐cover classifications, a forest clearance index, vegetation indices, drought indices, distances to infrastructure, topography, and peat depth, as well as the Oceanic Niño Index (ONI). The model performance consistently scores highly in both accuracy and precision across all years (>75% and >67.5% respectively), though recall metrics are much lower (>25%). Our results confirm the anthropogenic dependence of extreme fires in the region, with distance to settlements and distance to canals consistently weighted the most important driving factors within the model structure. Our results may help target the root causes of fire initiation and propagation to better construct regulation and rehabilitation efforts to mitigate future fires.

Assessment of current and future land use/cover changes in soil erosion in the Rio da Prata basin (Brazil)

In recent years, the Cerrado biome in Brazil (Brazilian savannah) has faced severe environmental problems due to abrupt changes in land use/cover (LUC), causing increased soil loss, sediment yield and water turbidity. Thus, this study aimed to evaluate the impacts of soil loss and sediment delivery ratio (SDR) over the last 30 years to simulate future scenarios of soil losses from 2050 to 2100 and to investigate an episode of sediment delivery that occurred in the Rio da Prata Basin (RPB) in 2018. In this study, the following were used: an estimation of soil losses for 1986, 1999, 2007 and 2016 using the Revised Universal Soil Loss Equation (RUSLE), an estimation of SDR, sediment export and sediment deposition using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, an association of RUSLE factor C to LUC data for 2050 and 2100 based on the CA-Markov hybrid model, and an estimation of future soil erosion scenarios for 2050 and 2100. The results show that over the last 30 years (1986–2016), there has been a reduction in the areas of highly intense and severe degrees. Future soil erosion scenarios (2050–2100) showed a 13.84% increase in areas of soil loss >10 Mg ha−1 year−1. The results highlighted the importance of assessing the impacts of LUC changes on soil erosion and the export of sediments to agricultural watersheds in the RPB, one of the best ecotourism destinations in Brazil. In addition, the increase in soil loss in the region intensified sediment yield events and increased water turbidity. Furthermore, riparian vegetation, although preserved, was not able to protect the watercourse, showing that it is essential to adopt the best management practices in the agricultural production areas of the basin, especially where ramps are extensive or the slope is greater than 2%, to reduce the runoff velocity and control the movement of sediments on the surface towards the drainage canals. The results of this study are useful for drawing up a soil and water conservation plan for the sustainable production of agriculture and maintenance of ecosystem services in the region.

Indicator for peat natural recovery in Sebangau National Park in Central Kalimantan, Indonesia

Most of the existing peatland area in Indonesia is degraded mainly due to human activities. This, in association with the construction of drainage canals, resulted in a lower water table compared to its natural condition, causing many changes. Although the criteria for damage and recovery have already been articulated into several existing regulations, yet the indicators for recovery have not been widely studied. For effective restoration, managers need to have basic data related to the initial condition of damaged areas or at least have data on areas that are able to recover naturally without human assistance. Random sampling was used to collect field data on vegetation structure and composition, including direct interviews with the resource persons. Observations made in several locations within the Sebangau National Park indicated that some areas are recovering naturally and relatively fast, although some are not. During 2017 forest fires, only 98.03 ha or burned areas were recorded. This can be seen from the species composition and the vegetation structure covering the studied area. Conditions in the field indicate that all peat forests have been fragmented through the existence of canals which are used for various activities.

Prevalence and Molecular Epidemiology of Cryptosporidium Infection in Clarias gariepinus Fish in Egypt.

This study investigated the prevalence and molecular detection of Cryptosporidium spp. in catfish (Clarias gariepinus). A total of 300 Carias gariepinus fish were collected from two freshwater sources: the Nile River (180) and drainage canals (120). The stomach and intestine epithelium of each individual fish sample were screened by modified Ziehl-Neelsen (mZN) staining technique for the detection of Cryptosporidium oocysts followed by the serological survey for detection of Cryptosporidium antibodies using Enzyme-Linked Immunosorbent Assay (ELISA) and molecular characterization using complemented DNA polymerase chain reaction (cPCR). ELISA showed higher prevalence of 69.3% than that prevalence obtained by mZN, 64% for the total examined Clarias gariepinus fish. Also, higher prevalence of Cryptosporidium infection 65.5% and 75.8% obtained by ELISA than 61.1% and 68.3% by mZN, in both fish groups from Nile River and Drainage canal, respectively. PCR analysis revealed the expected positive bands at 1056bp. DNA sequencing and phylogenetic analysis proved that the positive-PCR Cryptosporidium isolate identified in the present study was Cryptosporidium molnari. Freshwater fishes (Clarias gariepinus) are subjected to a high infection rate with Cryptosporidium spp.; the drainage canals obtained fishes showed higher prevalence than that collected from Nile River which indicates an important public health problem and a potential risk of drainage canals in Egypt. ELISA showed higher prevalence of cryptosporidiosis than mZN, for the total examined Clarias gariepinus fish and phylogenetic analyses confirmed this protozoal organism to be a novel species of Cryptosporidium molnari.

Turning old foes into new allies—Harnessing drainage canals for biodiversity conservation in a desiccated European lowland region

AbstractDrainage canals are widespread components of agricultural landscapes. Although canals have greatly contributed to biodiversity loss by desiccating wetlands, they have recently attracted conservation attention due to their potential to function as refugia for native species in intensively managed landscapes. However, their conservation role in complex landscapes composed of agricultural fields and desiccated but otherwise untransformed, semi‐natural habitats, on which canals still pose a heavy burden, is unknown. Improved understanding of drainage canals and related biodiversity in these landscapes could help unlock their potential and support synergistic land management for nature conservation and water resource management.We applied a multi‐taxon approach, including plants, butterflies, true bugs, spiders and birds, to (a) assess the conservation value of drainage canals with temporary water cover in a heavily drained European lowland region, (b) to test landscape‐level and local canal parameters for aiding prioritization among canals and (c) to propose a reconciliation‐based management framework that suits the interest of all stakeholders.We found that drainage canals and their banks concentrate more species across most taxa than semi‐natural, mostly grassland habitats, possibly due to micro‐environmental heterogeneity and the absence of low‐intensity annual management compared to grasslands. Canals traversing semi‐natural grasslands concentrate particularly high numbers of native species, but agricultural canals also support remarkable species richness. However, agricultural canals are important dispersal corridors for non‐native invasive plants, which may negatively affect native biodiversity. Canal size has little effect on biodiversity, but habitat stress is an important determinant. The higher the stress (due to sandiness and salinity), the higher the added value of canals to landscape‐wide biodiversity.Synthesis and applications. We show that drainage canals can harbour high biodiversity and should therefore be recognized as important novel ecosystems with high conservation value, even when cutting through semi‐natural grassland habitats. Canals have previously been considered detrimental to nature conservation due to their association with loss of wetlands. However, by reducing water loss with reversible obstructions, controlling invasive species and applying specific conservation measures, they may be turned into conservation allies without compromising long‐term interests of water management and agricultural land use.

Analysis of anthropogenic factors and health risks associated with overflow flooding of a drainage canal in Abidjan

Analysis of anthropogenic factors and health risks associated with overflow flooding of a drainage canal in Abidjan

Insecticide Resistance Variation among Three Culex pipiens (Diptera: Culicidae) Populations in Egypt

Several studies have reported on insecticide resistance in mosquitoes; however, there is a lack of information about the resistance of Culex pipiens in Egypt. This study was conducted to investigate insecticide resistance status in three Cx. pipiens populations. These populations were collected from two rural breeding sites and one urban site in Egypt. Al-Beshlawy drainage canal and El-Khartoum irrigation ditch were selected to represent rural sites in Giza and Beheira governorates, respectively. One man-made ground hole was selected in Tanta, Gharbia Governorate, as an urban breeding site. Insecticide residues were analysed in water samples collected from the three breeding sites. Four insecticides, malathion chlorpyrifos, deltamethrin and fipronil, were tested against Cx. pipiens third-instar larvae of three field populations and one insecticide-susceptible (reference) population. Four insecticide residues and one additive (piperonyl butoxide) were detected; only malathion and piperonyl butoxide concentrations exhibited significant differences among all breeding sites. The level of malathion residue in the Giza breeding site was significantly higher than those in the Gharbia and Beheira breeding sites. According to the lethal concentrations (LC50) of the applied insecticides, the susceptibility of Cx. pipiens third-instar larvae to different insecticides demonstrated the order fipronil > chlorpyrifos > deltamethrin > malathion. Variations in the percentage mortality of Cx. pipiens were observed following malathion application between the Gharbia population and with both Giza and Beheira populations. Culex pipiens populations exhibited low resistance to most tested insecticides; however, the populations of Giza and Beheira exhibited moderate resistance to malathion. The variation in the resistance of Cx. pipiens populations to malathion could provide new information about the intraspecific variation among some mosquito populations in Egypt.

PERENCANAAN ULANG SALURAN DRAINASE BERWAWASAN LINGKUNGAN JALAN SEMPALWADAK – KREBET SENGGRONG KABUPATEN MALANG

Road drainage is needed to prevent inudation as on Sempalwadak – Krebet Senggrong road Malang Regency. The inundation occurs as a result of uneven drainage construction so that the road becomes damaged and can distrupt people’s activities. The existing purpose of this thesis is to design an environmentally drainage and drainage canal, evaluate the hydraulic aspects of the drainage and drainage buildings, calculate construction costs, and plan scheduling. The data needed are topographic maps, rainfall data from the 3 closest stations: Blambangan, Bululawang, and Tangkilsari in 2010 until 2019, and the price of the Malang Regency work principal in 2020. The data is processed using the Gumbel I method, suitability test with Chi-Square method, and Smirnov-Kolmogorov by a period of 10 years, rain intensity with the Mononobe method and design flood discharge with the Rationel method. The calculation result the design rainfall is 109.63 mm/day; design flood discharge of 3.0807 m/second; environmentaly drainage using infiltration wells with dimensions of 0.7 meters with a depth of 1.8 meters; channel dimensions of 1 m x 1.2 m; construction costs of Rp. 7,797,328,046.09; construction duration 90 days.

Drainage canal impacts on smoke aerosol emissions for Indonesian peatland and non-peatland fires

Indonesia has experienced frequent fires due to the lowering of groundwater levels caused by drainage via extensive canal networks for agricultural development since the 1970s. However, the impact of canals on fire emissions is still poorly understood. Here we investigate canal impacts on smoke aerosol emissions for Indonesian peatland and non-peatland fires by quantifying the resulting changes of smoke aerosol emission coefficient (Ce) that represents total aerosol emissions released from per unit of fire radiative energy. First, we quantified the impacts of canal drainage and backfilling on water table depth (WTD) variations using field data and then expanded such impacts from field to regional scales by correlating field WTD to satellite terrestrial water storage (TWS) anomalies from Gravity Recovery and Climate Experiment. Second, we estimated Ce from fire radiative power and smoke-aerosol emission rates based on Moderate Resolution Imaging Spectroradiometer active fire and multi-angle implementation of atmospheric correction aerosol products. Finally, we evaluated the Ce variation with TWS anomalies. The results indicate: (a) Ce is larger in peatland fires than in non-peatland fires; (b) Ce increases significantly as TWS anomalies decrease for both peatland and non-peatland fires; and (c) Ce changes at nearly twice the rate in peatland for a given TWS anomaly range as in non-peatland. These phenomena likely result from the different fuel types and combustion phases prevalent under different moisture conditions. These findings support the Indonesian government’s recent peatland restoration policies and pave the way for improved estimation of tropical biomass burning emissions.

Assessment of Wastewater Irrigation Practices and Soil Properties in the Gazipur District of Bangladesh

The study deals with the assessment of wastewater irrigation practices and soil properties in connection with demographic information, availability of water sources, health hazards and the benefit-cost analysis in the Gazipur district of Bangladesh. A questionnaire survey was carried out to collect data on farmers' perceptions and responses to mainly agricultural production issues. It found that most respondents used wastewater because they had no alternative sources and sank their land during rush hour as well as the rainy season due to the lack of a proper wastewater disposal system by adjacent industries. The majority of respondents had skin problems from working with wastewater. No significant benefits were found from using direct wastewater in the fields. Irrigation costs could be reduced, however, fertilizer costs as well as the total cost of plant production were not adequate. The farmers did not get as much grown grain as they wanted. In addition, indirect wastewater users were rated better compared to direct users from the drainage canal. Farmers' perception showed that no major impact on the consumption of crops was noted, but rather the long-term use of wastewater in the field, which gradually reduced crop production and affected soil fertility. To evaluate Ca ++, Mg ++, K +, N, P, Cu, Pb, Cd and Ni from the investigation area; It was examined that the concentration of N, P and Cd was much higher than the standard limit. The heavy metal concentration series were as follows: Cd <Cu <Ni <Pb. In summary, the overall results of the study suggest that untreated or partially treated wastewater will slowly affect land and crop production in the long run.

Biomarkers of Exposure and Effect in Nile Tilapia (Oreochromis niloticus) Environmentally Exposed to Multiple Stressors in Egypt.

Chemical pollution poses adverse effects on aquatic organisms, including altered gene expression. This study, therefore, investigated the hepatic expression of biomarkers of exposure and effect in Oreochromis niloticus inhabiting the drainage canal of a sugarbeet factory (an industrially polluted habitat) and the Nile River (a reference habitat). Compared to the Nile River, the drainage canal contained significantly elevated levels of heavy metals (Cd, Fe, Mn, Co, and Pb), nitrate, ammonia, nitrite, chemical oxygen demand, and biological oxygen demand. The liver of O. niloticus from the drainage canal accumulated significantly higher concentrations of the heavy metals. O. niloticus from the drainage canal had significantly higher hepatic expressions of genes related to oxidative stress (GSTa, GPx, and NRF2), metal toxicity (MT), endocrine disruption (Vtg), and hypoxia (HIF1a) and a significantly lower hepatic expression of the apoptosis-associated CAS gene. CYP1A (a detoxification biomarker) expression did not exhibit significant differences. These results provide insights into complex adaptive responses of O. niloticus to multiple chemicals and support the utilization of molecular biomarkers as warning signals for water pollution.

Analysis of challenges, costs, and governance alternative for peatland restoration in Central Kalimantan, Indonesia

Restoration of degraded tropical peatland is considered to be one of the most cost-efficient measures in reducing greenhouse gas emissions and conserving biodiversity. Although benefits of restoration are often expected to substantially exceed the costs, most restoration projects are being carried out without clear cost analyses. This study provides empirical assessments of challenges and costs of the four peatland restoration projects managed by different proponents in Central Kalimantan, Indonesia based on key informant interviews, a follow-up survey and document analyses. We also reviewed existing policy contexts that can address some of the challenges to propose a governance alternative to sustain peatland restoration efforts. We found that many ecological challenges of peatland restoration projects were created by drainage canals leaving the peat to be dry and fire prone. Peatland degradation has been exacerbated by human activities and human-caused fires, and restoration efforts have faced many challenges due to lack of secure funding and complexity of governing the project implementation. The key informants we interviewed easily recognized direct costs for implementing restoration activities, but often left out indirect costs of addressing social challenges, such as expenses to engage local communities, in their assessments of the costs. Although our accounting is far from exhaustive, we found that indirect costs can add up to half of the total cost of peatland restoration projects. Current funding mechanisms for these projects mostly rely on international donors and private sectors, which make the long-term sustainability of the projects questionable. We argue that hybrid governance for a green business model, such as restoration and ecosystem services enterprises, with active participation from the public sector should be mainstreamed. The accounting framework developed in this study can be applied in other projects and should be further revised to systematically assess cost-effectiveness of restoration interventions.

Detection of potentially pathogenic Arcobacter spp. in Bangkok canals and the Chao Phraya River.

The management of pathogenic bacteria in waterways is a public health issue. Here, we investigated the concentrations of potentially pathogenic bacteria, Arcobacter spp. and Campylobacter spp., and Escherichia coli, by quantifying species-specific genes in surface water samples from canals and the Chao Phraya River from June 2017 to June 2018 in Bangkok, Thailand. We assessed the relationship between the specific bacterial concentrations, water quality, and seasonal changes. Arcobacter spp. were detected at high density in all samples and showed seasonal fluctuations according to analyses based on 16S rDNA and the invasion gene ciaB. High levels of 16S rDNA and dut gene of E. coli were detected in the polluted drainage canals. A high correlation was observed between E. coli and chemical and biochemical oxygen demand (COD and BOD), suggesting that untreated domestic wastewater was the source of the E. coli. In contrast, Arcobacter spp. were detected with high density even in water samples with relatively low COD, suggesting that Arcobacter spp. are more likely than E. coli to survive in the water environment. The analysis of 16S rDNA and ciaB gene sequence analyses indicated that the Arcobacter spp. isolated from the drainage canals were A. butzleri and A. cryaerophilus.

Seeding the drainage canal of a wastewater treatment system for the natural rubber industry with rubber for the enhanced removal of organic matter and nitrogen

Current pretreatment methods for wastewater from natural rubber (NR) factories either have low rubber recovery efficiency or are costly to operate. A wastewater treatment system was developed that combines a pretreatment canal (PTC) seeded with rubber, an anaerobic baffled reactor (ABR), and a down-flow hanging sponge (DHS) reactor. The PTC is simple to implement and contributes to not only rubber recovery but also organic matter removal in the ABR and nitrogen removal in the DHS reactor. In experiments, the PTC recovered 16.6% of residual rubber through coagulation. The ABR increased the chemical oxygen demand removal efficiency and methane recovery compared with other anaerobic reactors treating raw NR wastewater. The DHS reactor removed 30.7% of total inorganic nitrogen (TIN) by nitrification, anaerobic ammonia oxidation and denitrification. Feeding the bottom stage of the DHS reactor with sodium acetate solution increased the TIN removal efficiency to 87.8%. The water quality of the final effluent achieved the Vietnamese standards for the NR industry. Microbial community analysis was performed to identify the dominant microorganisms and mechanisms in the PTC, ABR, and DHS reactor.