Wastewater Irrigation Research Articles

Reuse of wastewater for irrigation of coriander in Morocco: Evaluation of effects on crop growth parameters

AbstractCurrently, the convergence of climate change, population growth, and deteriorating water quality has triggered a scarcity of freshwater resources, presenting substantial hurdles for agricultural endeavors. Consequently, repurposing treated wastewater for agricultural use is gaining prominence. This strategy offers a noteworthy advantage by furnishing an alternative water source, distinct from conventional freshwater, for agricultural irrigation. The considered irrigation water categories encompass treated wastewater, sewage treated with supplementary fertilization, treated water of a specific quality, and treated water quality fortified with fertilizer. An assessment of the treated wastewater extracted from the Imzouren‐Bni Bouayach treatment facility was undertaken, encompassing scrutiny of its physical, chemical, and bacteriological attributes. This analysis yielded measurements for a range of parameters, including pH, temperature, electrical conductivity, dissolved oxygen, suspended matter, biochemical oxygen demand, chemical oxygen demand, total phosphorus, nitrate, nitrite, total coliforms, fecal coliforms, and fecal streptococci. These measurements align with acceptable thresholds for direct discharge and are following Morocco's established water quality standards tailored for irrigation. In light of the soil analysis, the soil is classified as alkaline, with a pH of 8.2, and displays low salinity, evidenced by an electrical conductivity of 2.42 mS/cm. Furthermore, the soil exhibits deficiencies in organic matter and essential nutrients, with carbon content measuring 0.84%, organic matter at 1.45%, nitrogen at 0.07%, phosphorus at 10.6 mg/L, and potassium at 56.5 mg/L. The utilization of treated wastewater for irrigation purposes bestows the crop with a dependable water supply, ensuring stability in its growth.

Influence of Industrial Wastewater Irrigation on Heavy Metal Content in Coriander (Coriandrum sativum L.): Ecological and Health Risk Assessment.

The primary objective of this study was to determine the heavy metal contents in the water-soil-coriander samples in an industrial wastewater irrigated area and to assess the health risks of these metals to consumers. Sampling was done from areas adjoining the Chistian sugar mill district Sargodha and two separate sites irrigated with groundwater (Site 1), and sugar mill effluents (Site 2) were checked for possible metal contamination. The water-soil-coriander continuum was tested for the presence of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Ni), lead (Pb), and zinc (Zn). The mean concentrations of all metals were higher than the permissible limits for all studied metals except for Mn in the sugar mill wastewater, with Fe (8.861 mg/L) and Zn (9.761 mg/L) exhibiting the highest values. The mean levels of Fe (4.023 mg/kg), Cd (2.101 mg/kg), Cr (2.135 mg/kg), Cu (2.180 mg/kg), and Ni (1.523 mg/kg) were high in the soil at Site 2 in comparison to the groundwater irrigated site where Fe (3.232 mg/kg) and Cd (1.845 mg/kg) manifested high elemental levels. For coriander specimens, only Cd had a higher mean level in both the groundwater (1.245 mg/kg) and the sugar mill wastewater (1.245 mg/kg) irrigated sites. An estimation of the pollution indices yielded a high risk from Cd (health risk index (HRI): 173.2), Zn (HRI: 7.012), Mn (HRI: 6.276), Fe (HRI: 1.709), Cu (HRI: 1.282), and Ni (HRI: 1.009), as all values are above 1.0 indicating a hazard to human health from consuming coriander irrigated with wastewater. Regular monitoring of vegetables irrigated with wastewater is strongly advised to reduce health hazards to people.

Potential hazards of typical small molecular organic matters in shale gas wastewater for wheat irrigation: 2-butoxyethanol and dimethylbenzylamine

2-butoxyethanol (BE) and dimethylbenzylamine (DMBA) are small molecular organic compounds commonly found in shale gas wastewater (SGW) and environmental samples, yet their environmental risks in exposure and irrigation reuse have not been thoroughly studied. From the perspectives of physicochemical properties and toxicity, seven groups of irrigation treatment were designed for wheat irrigation according to the concentration gradient. Overall, wheat growth was normal, but higher DMBA concentrations resulted in more severe growth inhibition. The absorption of BE by various tissues of wheat was positively correlated with its concentration, while the absorption of DMBA by wheat stems showed the same trend. Interestingly, there was no significant difference in the absorption of DMBA by wheat grains in different groups. The detection results of nutritional and heavy metal elements in wheat tissues showed that the presence of organic compounds changed the relative sensitivity of wheat leaves and grains to some elements (such as Mg, Mn, Mo, etc.) enrichment. The Cd and Pb contents of wheat grains in all groups complied with national safety standards, but the As or Cr concentration in wheat grains treated with BE or DMBA exceeded the limits in some cases. Transcriptome sequencing, GO annotation, and KEGG enrichment analysis revealed similar gene functions and metabolic pathways enriched by BE and DMBA. The safe and sustainable agricultural reuse of SGW still has great potential as a promising water resources management strategy.

Model based optimization of fertilization with treated wastewater reuse

Treated wastewater contains vital crop nutrients and offers the possibility for not only irrigation but also fertilization from a renewable source. The feasibility of replacing conventional chemical fertilizers with wastewater reuse is investigated, focusing on the implications of coupling irrigation and fertilization. We consider a multi-objective dynamic optimization problem of crop irrigation and fertigation with treated wastewater, with the objectives of maximizing crop production and minimizing environmental costs. A double modeling method is proposed that relies on both a modern complex crop model – the simulation model – and a low-order dynamical systems model – the control model – to solve efficiently the optimization problem, whilst maintaining a detailed representation of the system of study. Through a case study, we show that it is possible to achieve high levels of crop production. The maximum nutrient concentration of the reclaimed waters CNmax is a key parameter of the system performance: when CNmax is high enough, it is possible to substitute entirely conventional fertilization for irrigation with wastewater. However, when CNmax is small, our results highlight that meeting crop needs would require excessive irrigation, with the added risk of dilution of the nutrients already present in soil. We find that there is a maximum amount of nutrients that can be delivered efficiently to the soil-crop system and identify the conditions when wastewater irrigation is only be capable of providing a portion of the crop needs and should be complimented with other sources of fertilization. The double modeling method and the control model provide a means to estimate the key quantities to determine the best strategy to adopt for wastewater fertilization, as well as to obtain efficient and simple controls, that could be applied in practice.

Combination of intercropping maize and soybean with root exudate additions reduces metal mobility in soil-plant system under wastewater irrigation

The effects of root exudates and irrigation with treated wastewater on heavy metal mobility and soil bacterial composition under intercropping remain poorly understood. We conducted a pot experiment with maize and soybean grown in monocultures or intercultures, irrigated with either groundwater or treated wastewater. In addition, the pre-collected root exudates from hydroponic culture with mono- or inter-cropped maize and soybean were applied to the soil at four levels (0 %, 16 %, 32 % and 64 %). The results showed that application of root exudates increased plant growth and soil nutrient content. The analysis of “Technique for Order of Preference by Similarity to Ideal Solution” for higher plant biomass and lower soil Cd and Pb concentrations indicated that the best performance of soybean under treated wastewater irrigation was recorded under intercropping applied with 64 % of exudates, with a performance score of 0.926 and 0.953 for Cd and Pb, respectively. The second-best performance of maize under treated wastewater irrigation was also observed under intercropping applied with 64 % of exudates. Root exudate application reduced heavy metals migration in the soil-plant system, with a greater impact in intercropping than in monocropping. In addition, certain soil microorganisms were also increased with root exudate application, regardless of irrigation water. This study suggests that appropriate application of root exudates could potentially improve plant growth and soil health, and reduce toxic heavy metal concentrations in soils and plants irrigated with treated wastewater.

Tetracyclines uptake from irrigation water by vegetables: Accumulation and antimicrobial resistance risks

Wastewater irrigation may introduce antibiotic residues in the soil-plant systems. This study aimed to investigate the uptake of tetracyclines by spinach and collard greens and assess associated ecological and human health risks. Synthetic wastewater spiked with 1 ppm and 10 ppm of oxytetracycline, doxycycline, and tetracycline was used to grow vegetables in a greenhouse pot experiment. The uptake and accumulation of the tetracyclines were low and residual concentrations in the soil were negligible. All the tetracyclines were detected at concentrations ranging from 1.68 to 51.41 μg/g (spinach) and 1.94–30.95 μg/g (collard greens). The accumulation rate was in a dose-response scenario with a bioconcentration factor of 6.34 mL/kg (spinach) and 2.64 mL/kg (collard greens). Oxytetracycline had the highest accumulation in leaves, followed by doxycycline and tetracycline, and the residual concentrations followed the same order. The highest residual concentration was in soils receiving 10 ppm oxytetracycline. Residual concentrations in the soil were lower than accumulated levels and exerted negligible ecological risks. Tetracyclines accumulation in spinach significantly differed between the vegetables demonstrating a subspecies difference in uptake and accumulation. Ecological risk quotient (RQ) and human health risk quotient (HQ) were below thresholds that would exert toxicity and resistance selection impacts. Although RQs and HQs are low (<0.1), this study shows that the vegetables accumulate tetracyclines from irrigation water, posing plausible human health risks to allergic individuals. Similarly, the ecological risks cannot be ignored because the synergistic and antagonistic effects of sublethal concentrations can perturb ecosystem processes.

Morpho-anatomical adaptations of dominantly grown wild Datura inoxia to wastewater resource: Productivity and ecological issues

With the increasing global water scarcity, wastewater irrigation has become widespread, but it can have detrimental ecological consequences. Although wastewater contains valuable nutrients for plants, improper treatment or the use of untreated wastewater in irrigation can negatively impact soil fertility and plant growth. This study is divided into two parts: firstly, a phytosociological survey was conducted to identify plant species with the highest importance value index (IVI) in the vicinity of wastewater-irrigated areas. Secondly, a comparative morpho-anatomical analysis was carried out to investigate the morpho-anatomical adaptations of the species with the highest IVI under wastewater irrigation compared to normal water irrigation. The results of the phytosociological survey revealed the presence of 51 plant species in the vicinity of the wastewater-irrigated areas, with varying relative densities and coverage. Datura inoxia exhibited the highest IVI (28.79), followed by Xanthium strumarium (24.34), while Lippia nodiflora showed the lowest IVI (1.86). The morphological growth of D. inoxia was superior under normal water irrigation, but the average root length was greater under wastewater irrigation. Regarding cell anatomy, cell thickness and cell area characteristics in the dermal, ground, and vascular tissues of the stem and root tended to be greater under wastewater treatment. However, the opposite trend was observed in leaf anatomical analysis, possibly due to the combined effect of wastewater and climatic conditions. Stem and root xylem thickness were greater under wastewater irrigation, whereas phloem thickness was higher under normal water irrigation. The number of vascular bundles in the stem, root, and leaf was higher under wastewater treatment compared to normal water irrigation, but their arrangement was circular in the latter and scattered under wastewater irrigation. Datura inoxia demonstrated strong adaptive potential under wastewater irrigation, as indicated by its highest relative density, coverage, and IVI, suggesting its suitability for phytoremediation. However, due to the low relative density, coverage, and IVI of many other species, the use of untreated wastewater for irrigation cannot be appreciated.

Numerical modeling of groundwater flow and nitrate transport in karst and wastewater irrigated agricultural and forest landscapes, PA, USA

AbstractUnderstanding the influence of treated wastewater reuse for irrigation on nitrate groundwater contamination in karstic landscape is critical for developing long‐term management plans and assessing the sustainability of these practices. The Pennsylvania State University has been operating a secondary treated wastewater effluent irrigation site—the “Living Filter”—since the 1960s. The objective of this study is to develop a regional groundwater flow and nitrate transport model to assess the impact of treated wastewater and disposal of large volumes of wastewater for irrigation of agricultural and forested lands on nitrate groundwater contamination in a karst landscape in the Spring Creek Watershed in central Pennsylvania. The modular three‐dimensional finite‐difference ground‐water flow model (MODFLOW) was used to construct the groundwater flow model of the local aquifer and simulate three‐dimensional regional changes in the water table over time. The simulation of nitrate fate and transport in the aquifer was conducted by developing a groundwater mass transport model using MODFLOW and a modular three‐dimensional transport multi‐species model (MT3DMS). The calibrated groundwater model yielded a root mean square error of 5.41 ft for the area of irrigation and 24.67 ft for the entire modeled area. Results of the calibrated model show the extension of a nitrate plume over most of the study area with concentrations below 10 mg·L−1 under the current 2015 setting and the long‐term 2035 scenario of increased irrigation rates. The nitrate migration was dominated by the presence of two high conductivity groundwater troughs adjacent to the study area resulting in a near steady‐state total mass since the 1990s.

Domestic sewage wastewater irrigation in the semi‐urban ecosystem on soil physical–chemical properties and environmental food security perspectives of two vegetables

AbstractNowadays, using domestic sewage wastewater for agricultural irrigation is becoming increasingly important for sustainable water resources management. Several national and international programs have been implemented to mitigate wastewater. However, it is important to ensure that these measures are affordable, effective, and sustainable. The aim of the present study is to determine, after all these mitigations, whether these domestic sewage wastewaters can be used as a potential irrigation source and at the same time ensure environmental food security. With these objectives, we analyzed the consequences of domestic sewage effluent irrigation on soil physical–chemical properties and nutritive and nutraceutical properties of cultivated green vegetables, Luffa acutangula (L.) Roxb. and Lagenaria siceraria (Molina) Standl., in the semi‐urban ecosystem compared with well water irrigated crops in a rural area. The quality status of both well water irrigated and domestic sewage wastewater irrigated soil samples showed similar and/or comparable values, that is, domestic sewage wastewater irrigation does not harm the soil quality and both were comparable with the permissible limits of BIS (Bureau of Indian Standards) including heavy metal contents. And positively supporting the objective of our study, the nutrient status/proximate composition of both the vegetables in terms of protein, gross energy, carbohydrate, etc., were higher in domestic sewage wastewater irrigated crops compared with the well water irrigated crops. The antioxidant activity also exhibited a significant increase in the sewage wastewater irrigated crops rather than the well water irrigated ones. Hence the results of the present study state that due to the impact of the mitigation measures, domestic sewage wastewater is now pertinent to be used as an irrigation source and also a possible organic fertilizer without any ambiguity. Moreover, more field‐oriented studies may ensure the potential of wastewater irrigation for sustainable crop production without any pollution, particularly in a semi‐urban area.

Wastewater driven trace element transfer up the food chain in peri-urban agricultural lands of Lahore, Pakistan

In peri-urban agricultural lands of Lahore city, untreated wastewater from trans-boundary Hudiara drain is widely used for agriculture. The irrigated water may pose a hazard of trace element (TE) contamination in agricultural produce and consequently threat to human health. This study was designed to investigate the quality and transferability of TE contamination in water, soil, fodder and buffalo milk. Samples from the 4 assets and products were collected at upstream, midstream and downstream sites along Hudiara drain. Potentially toxic elements (Cd, Cu, Ni and Zn) were analyzed using standard methods. Physicochemical analysis of water, bioaccumulation factor (BAF) from soil to fodder and Pearson correlation of metal contamination in water, soil, fodder and milk were determined. TE contamination increased from upstream to downstream site. Highest Cd concentration in water, soil, fodder and milk was 0.29 mg/L (downstream), 1.10 mg/kg (midstream), 2.12 mg/kg (downstream) and 0.29 mg/L (downstream), respectively, which surpassed permissible limits for all the 4 mediums. Similar results were found with Cu, Ni and Zn which increased downstream and the concentrations higher than permissible limits in all mediums except soil. Significantly high Hazard Index (HI) values were recorded for irrigation wastewater (23.25–31.75), fodder (7.41–11.13), and milk (11.12–17.85), which were increasing down the stream of drain. All 4 metals have shown strong positive correlation among water, soil, fodder and milk, showing transferability risk up to food chain. Transfer of TE from soil to fodder was highest for Ni (BAF 8.44) and lowest for Zn (BAF 0.41) with the following ascending trend: Zn < Cd < Cu < Ni. The physicochemical parameters of drain water also did not meet the permissible limits for wastewater irrigation. Use of untreated water of Hudiara drain for agriculture in peri-urban areas of Lahore needs to be stopped until appropriate treatment and reuse.

Long-term performance of ZVI-stimulating anaerobic/aerobic system - PEI modified ceramic membrane SMBR in reusing food wastewater for irrigation: An industrial project and microbial community shift

A large-scale project was carried out using an integrated treatment system composed of anaerobic and aerobic unit followed by ceramic membrane SMBR for reclaiming 200 m3/d of food wastewater for the purpose of irrigation. Utilization of ZVI technology to facilitate the organic contaminants degradation in UASB and aerobic unit in the operation of successive 240 days was investigated. A membrane flux of around 30 LMH was stably attained in a novel PEI-modified flat sheet ceramic membrane SMBR equipped with in situ intensive mechanical cleaning bush system. The ceramic MBR system investigated had significantly alleviated membrane fouling and no severe membrane fouling occurred throughout the whole filtration process. Overall, the combined treatment system can produce high quality reusable water for irrigation and the final effluent had a COD of around 120 mg/L and BOD5 of around 32 mg/L, respectively. Finally, variations in dominant species in both initial sludge Day-1 and sludge Day-240 in ZVI assisting UASB and aerobic unit was further unraveled by the high throughput sequencing analysis.

Accumulation and Toxicity of Polycyclic Aromatic Hydrocarbons in Long-Term Soil Irrigated with Treated Wastewater

Our study focuses on examining the effects of treated wastewater irrigation (TWWI) on agricultural soils in water-scarce regions, with a specific emphasis on the presence and accumulation of polycyclic aromatic hydrocarbons (PAHs). This issue is particularly significant due to its potential threats to environmental security. During our research, we discovered the existence of 16 different PAHs in these soils, which are known to have harmful impacts on ecosystems and human health. The concentration of total PAHs ranged from 163.9 ng g−1 to 9177.4 ng g−1, with 4- and 5-ring PAHs being the most dominant contributors. The PAHs Fluoranthene and Pyrene were found to be the most prevalent in all soil samples. Comparing the PAH concentrations in our research area to those reported in other studies, we observed that the agricultural areas in our study were more contaminated. Through positive matrix factorization (PMF) and diagnostic ratios (DRs) analyses, we identified petroleum combustion, vehicular emissions, as well as coal, grass, or wood combustion as the primary sources of PAH contamination. We also noted a negative correlation between clay, silt, pH, and PAH concentrations, while a significant positive relationship was observed between total organic carbon (TOC), sand, and PAHs. Based on the computed environmental risk index value, the presence of PAHs in the area poses a moderate to high level of ecological risk. TWWI was identified as the main contributor to PAHs in the agricultural soils we studied. Therefore, it is crucial to establish and enforce standards for wastewater reuse in agricultural fields before irrigation takes place.

Investigating the effects of irrigation with indirectly recharged groundwater using recycled water on soil and crops in semi-arid areas

The utilization of direct wastewater for irrigation poses many environmental problems such as soil quality deterioration due to the accumulation of salts, heavy metals, micro-pollutants, and health risks due to undesirable microorganisms. This hampers its agricultural reuse in arid and semi-arid regions. To address these concerns, the present study introduces a recent approach that involves using indirectly recharged groundwater (GW) with secondary treated municipal wastewater (STW) for irrigation through a Soil Aquifer Treatment-based system (SAT). This method aims to mitigate freshwater scarcity in semi-arid regions. The study assessed GW levels, physicochemical properties, and microbial diversity of GW, and soil in both impacted (receiving recycled water) and non-impacted (not receiving recycled water) areas, before recycling (2015–2018) and after recycling (2019–2022) period of the project. The results indicated a significant increase of 68–70% in GW levels of the studied boreholes in the impacted areas. Additionally, the quality of indirectly recharged GW in the impacted areas improved notably in terms of electrical conductivity (EC), hardness, total dissolved solids (TDS), sodium adsorption ratio (SAR), along with certain cations and anions (hard water to soft water). No significant difference was observed in soil properties and microbial diversity of the impacted areas, except for EC and SAR, which were reduced by 50% and 39%, respectively, after the project commenced. The study also monitored specific microbial species, including total coliforms, Escherichia coli (as indicator organisms), Shigella, and Klebsiella in some of the harvested crops (beetroot, tomato, and spinach). However, none of the analysed crops exhibited the presence of the studied microorganisms. Overall, the study concludes that indirectly recharged GW using STW is a better sustainable and safe irrigation alternative compared to direct wastewater use or extracted hard GW from deep aquifers.

The impact of wastewater-irrigated urban agriculture on microbial quality of drinking water at household level in Addis Ababa, Ethiopia

ABSTRACT Wastewater irrigation may reintroduce fecal pathogens to households and cause drinking water contamination. The aim of this study was to assess the effect of wastewater irrigation on the quality of drinking water among wastewater-irrigating urban farming households. Drinking water samples from 52 households of farming communities in 19 sampling sites were collected twice at PoS and PoC. The microbial quality of the water was assessed using E. coli counted by membrane filtration. Samples collected from exposed households at PoC were 100% positive for E. coli with mean E. coli at PoC increased 10× from the PoS and 3× higher compared to PoC in the unexposed households. The absence of hand washing water (ATE = 8.14), water storing (ATE = 7.75) and intermittent water supply (ATE = 6.25) were significant factors for the increased E. coli at PoC. Breaking the path of the pathogens from the farm to the house and from PoS to PoC needsintervention.

Storage, Transport, and Fate of Perfluoroalkyl Acids (PFAAs) in a Wastewater Reuse and Groundwater Recharge System

AbstractPerfluoroalkyl acids (PFAAs), a group of synthetic compounds associated with adverse human health impacts, are commonly found in effluent discharged from wastewater treatment facilities. When that effluent is used for irrigation, the fate of PFAAs depends strongly on soil PFAA retention properties and effluent PFAA loading history. The relative importance of PFAA retention factors under natural field‐scale conditions remains uncertain, and the historical record of effluent PFAA concentrations is limited. Using soil cores collected from the Penn State Living Filter (irrigated with treated wastewater effluent for nearly 60 years), we evaluated PFAA mass balance in the irrigated soils and estimated historical effluent PFAA concentrations. Total accumulated perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) masses measured in soils in 2014 were more than 450 times greater than annual mass loads applied during the 2020 effluent irrigation. Column mass balance models reproduced the observed PFOS and PFOA profiles, providing an estimate of historical effluent PFOS and PFOA concentrations: 70–170 ng L−1 and 1,000–1,300 ng L−1, respectively. Estimated concentrations were comparable to measurements in other wastewater effluents in the 1990s and 2000s, indicating that wastewater‐irrigated soils can serve as integrated records of historical PFAA loading to the environment. Mass balance calculations suggest that PFOS breakthrough to groundwater occurred 50 years after the start of wastewater irrigation, whereas simulated PFOA breakthrough occurred after only 10 years of irrigation. While wastewater irrigation of soils facilitates retention and reduces effluent PFAA loading to surface waters, resulting PFAA storage in soils potentially creates long‐term sources of PFAAs to groundwater.

Biochar and mycorrhiza enhance soil carbon storage and reduce CO2 emissions in wastewater-irrigated turf

Abstract Irrigation with recycled wastewater can reduce freshwater demand and improve soil fertility, but it can also increase CO2 emissions from soil and contribute to global warming. This study investigated whether biochar and mycorrhiza can reduce CO2 emissions and enhance soil quality in wastewater-irrigated turf. A factorial experiment was conducted with four levels of biochar (0, 0.5, 1, and 1.5%), two mycorrhiza (with and without), and two types of irrigation water (freshwater and recycled wastewater). Soil CO2 and H2O emissions, moisture and temperature, and chemical and physical properties were measured for 3 months. Biochar and mycorrhiza treatments significantly reduced CO2 emissions by 19.4–45.0% compared to the control treatment. The combination of biochar at a 1.5% level with mycorrhiza had the highest emission-reducing effect. Biochar and mycorrhiza treatments also reduced H2O emissions by 8.1–14.6%, increased soil organic matter, carbon, and total nitrogen, regulated soil EC and pH, and improved soil porosity and aggregate stability. The results suggest that biochar and mycorrhiza can be effective strategies to mitigate CO2 emissions and improve soil quality in wastewater irrigation. The combination of biochar with mycorrhiza can have synergistic benefits for soil carbon storage and conservation.

Socioeconomic, environmental, and health impacts of reusing treated wastewater in agriculture in some Arab countries, including occupied Palestine, in view of climate change

The increase in water stress and shortage, facing many countries around the world, is one of the main difficulties confronting practical progress and sustainable development and management. Accordingly, managing the water assets of many countries around the world is nowadays a big challenge due to immense difficulties and vulnerabilities, including rapid industrialization and urbanization processes, population growth, geopolitical instability, and the effects of environmental changes, namely global warming and climate change. Because of global fresh waters scarcity and shortage, the demand for using non-conventional water resources, such as reusing treated wastewater for irrigation and industrial purposes, has become a nessitiy. However, the reuse of effluents for agricultural irrigation can have negative impacts on crop quality and soil conditions, as well as on public health and the environment. Moreover, improper management of agricultural irrigation with treated wastewater can also cause problems for plant production and soils’ physical and chemical propeties. This paper investigates the status of freshwater and wastewater in view of climate change, and socioeconomic, environmental, and health impacts of reusing treated wastewater for irrigation in the Arab region, with the focus on the Occupied Palestinian Territories (OPT), as an example. The paper concludes that: 1) Approximately 13.2 billion cubic meters (BCM) of wastewater is yearly produced in the Arab countries, of which 5.7 BCM (43.2%) is treated and 7.5 MCM (56.8%) is untreated and dumped in open environments; 2) Regarding the OPT, where more than 87% of its fresh water resources are controlled and forcefully taken by the Israeli occupation authorities, Palestinians discharge large amounts of untreated wastewater into open lands (as in the case of the occupied West Bank) and in the Mediterranean Sea (as in the case of occupied and besieged Gaza Strip); and 3) The reused portion of treated wastewater in the OPT is close to zero.

Effects of diclofenac, sulfamethoxazole, and wastewater from constructed wetlands on Eisenia fetida: impacts on mortality, fertility, and oxidative stress.

Soil contamination with micropollutants is an important global problem and the impact of these pollutants on living organisms cannot be underestimated. The effects of diclofenac (DCF) and sulfamethoxazole (SMX), their mixture (MIX), and wastewater containing these drugs on the mortality and reproduction of Eisenia fetida were investigated. The impact on the activities of antioxidant enzymes in earthworm cells was also assessed. Furthermore, the influence of the following parameters of the vertical flow constructed wetlands on wastewater toxicity was investigated: the dosing system, the presence of pharmaceuticals and the plants Miscanthus giganteus. The compounds and their mixture significantly affected the reproduction and mortality of earthworms. The calculated values of LC50,28 days values were 3.4 ± 0.3 mg kg-1 for DCF, 1.6 ± 0.3 mg kg-1 for SMX, and 0.9 ± 0.1 mg kg-1 for MIX. The EC50 (reproduction assay) for DCF was 1.2 ± 0.2 mg kg-1, whereas for SMX, it was 0.4 ± 0.1 mg kg-1, and for MIX, it was 0.3 ± 0.1 mg kg-1, respectively. The mixture toxicity index (MTI) was calculated to determine drug interactions. For both E. fetida mortality (MTI = 3.29) and reproduction (MTI = 3.41), the index was greater than 1, suggesting a synergistic effect of the mixture. We also observed a negative effect of wastewater (raw and treated) on mortality (32% for raw and 8% for treated wastewater) and fertility (66% and 39%, respectively) of E. fetida. It is extremely important to analyze the harmfulness of microcontaminants to organisms inhabiting natural environments, especially in the case of wastewater for irrigation of agricultural fields.

Uptake and accumulation of emerging contaminants in processing tomato irrigated with tertiary treated wastewater effluent: a pilot-scale study.

The reuse of treated wastewater for crop irrigation is vital in water-scarce semi-arid regions. However, concerns arise regarding emerging contaminants (ECs) that persist in treated wastewater and may accumulate in irrigated crops, potentially entering the food chain and the environment. This pilot-scale study conducted in southern Italy focused on tomato plants (Solanum lycopersicum L. cv Taylor F1) irrigated with treated wastewater to investigate EC uptake, accumulation, and translocation processes. The experiment spanned from June to September 2021 and involved three irrigation strategies: conventional water (FW), treated wastewater spiked with 10 target contaminants at the European average dose (TWWx1), and tertiary WWTP effluent spiked with the target contaminants at a triple dose (TWWx3). The results showed distinct behavior and distribution of ECs between the TWWx1 and TWWx3 strategies. In the TWWx3 strategy, clarithromycin, carbamazepine, metoprolol, fluconazole, and climbazole exhibited interactions with the soil-plant system, with varying degradation rates, soil accumulation rates, and plant accumulation rates. In contrast, naproxen, ketoprofen, diclofenac, sulfamethoxazole, and trimethoprim showed degradation. These findings imply that some ECs may be actively taken up by plants, potentially introducing them into the food chain and raising concerns for humans and the environment.

Microbial food safety of lettuce produced under irrigated wastewater from Onyasia River in Ghana

Fresh produce continues to be the main source of foodborne illness outbreaks, particularly in developing countries where water stress results in the use of surface wastewater all year round for irrigation of vegetables. The objective of the current study was to evaluate the microbial quality of lettuce irrigated with wastewater from Onyasia river. Lettuce and soil were sampled from selected vegetable farms on the Eastern gate of the Ghana Atomic Energy Commission land alongside surface wastewater from the Onyasia river, which is used as the main source for irrigation. Samples were analyzed for aerobic mesophilic plate counts, total coliforms count, fecal coliforms count, Salmonella counts and intestinal parasites using standard methods. Surface wastewater was found to be contaminated with mean fecal coliform counts of log 3.50 cfu/100 mL. Enterobacter cloacae, Acinetobacter baumannii, and Klebsiella pneumonia were also isolated from the wastewater samples. No intestinal parasite egg was detected in wastewater samples. While fecal coliforms and Salmonella spp were not detected, mean aerobic mesophilic plate counts (log 4.82 cfu/g) and total coliforms count (log 3.50 cfu/g) were recorded in the lettuce samples. Enterobacter asburiae, Acinetobacter baumannii, Klebsiella variicola and Citrobacter freundii were isolated from lettuce. Infective larvae of helminths were observed on lettuce samples at a density of 36/g-648/g with a mean of 342/g. Soil samples recorded a mean aerobic mesophilic plate counts of log 6.14 cfu/g, total coliforms count of log 4.90 cfu/g while fecal coliforms and Salmonella spp were not detected (<1 cfu/g) Soil samples yielded a mean infective larval count of 1941.5 larvae/g and a Strongyle count of 12 eggs/g. Even though less than 1 cfu/g of Salmonella spp were found, the study found lettuce to be contaminated with other foodborne bacteria pathogens, opportunistic bacteria pathogens, eggs and infective larvae of intestinal parasites of health importance. As a consequence, the microbial food safety risk associated with wastewater irrigated vegetables was observed to be high with possible public health implications. It is recommended that wastewater from the Onyasia River should be treated before use for irrigation of lettuce.