Irrigation Of Vegetables Research Articles

Assessing bacterial diversity and antibiotic resistance dynamics in wastewater effluent-irrigated soil and vegetables in a microcosm setting

Water scarcity is one of the main challenges in sustainable agricultural development particularly in developing countries therefore, irrigation of food crops with wastewater effluent has become a common practice in order to meet the growing food demand. The aim of this study was to determine the impact of wastewater irrigation on bacterial community and antibiotic resistance dynamics in soil and vegetables in an agricultural setting. To determine bacterial diversity, occurrence and overall dynamics of antibiotic resistant genes (ARGs) in effluent irrigated soil and vegetables, 16S rRNA gene metagenomics, shotgun metagenomics and molecular PCR technique were utilized. A shift in bacterial community profile was observed as notable reduction in proteobacteria and increase in firmicutes phyla from the microcosm soil following wastewater effluent irrigation. Shotgun metagenomics revealed diverse ARGs belonging to at least nine different classes of antibiotics in the effluent wastewater. However, only blaTEM (beta-lactamase) and aadA (aminoglycoside) resistance gene sequences were identified in microcosm soil following irrigation and only blaTEM was detected on effluent irrigated vegetable surfaces (spinach and beetroots). From the study, only blaTEM gene was identified across all samples; effluent wastewater, effluent-treated soil, and vegetables. The data suggests a possible dissemination and persistence of the beta-lactamase blaTEM gene from effluent wastewater into agricultural soil and vegetables. This study enhances our understanding of antibiotic resistance spread and highlights the importance of monitoring antibiotic resistance in agro-systems, which is critical for informing policies aimed at sustainable use of wastewater effluent in water-stressed countries.

Global incidence of helminthic contamination of vegetables, cucurbits and fruits: A systematic review and meta-analysis

Accidental ingestion of infective stages of helminths through consumption of contaminated vegetables and fruits causes a wide range of food-borne diseases in humans. This systematic review and meta-analysis evaluated the global incidence of helminthic contamination of vegetables, cucurbits and fruits. Several databases (Science Direct, Web of Science, PubMed, Scopus, and Google Scholar) were searched for literature published prior to November 2020. Overally, 184 articles (32 countries) met the inclusion criteria. Among these, 137 studies documented helminthic contamination in vegetables, 46 in cucurbits and 9 were in fruits. The pooled incidence (95% confidence interval) was 31% (26%–37%) for vegetables, 20% (14%–27%) for cucurbits and 20% (8%–37%) for fruits. The highest incidence rate was found in the Western Pacific WHO region (54%; 9%–95%). The most prevalent parasitic agents were Ascaris lumbricoides eggs (12%; 9%–15%) and Strongyloides stercoralis larvae (12%; 8%–16%) in vegetables, S. stercoralis larvae (10%; 5%–15%) and Toxocara spp. eggs (10%; 3%–21%) in cucurbits, and Trichuris trichiura eggs (9%; 1%–22%) in fruits. The highest incidence rate was found to be associated with lower-middle income countries (34%, 28%–41%) and regions with a tropical rainforest climate (50%, 10%–91%). The potential role of vegetables, cucurbits, and fruits in the spread of helminthic parasites was revealed. Utilizing clean water for irrigation, proper washing and cooking of vegetables and improved sanitary practices can decrease the public health hazard regarding the consumption of vegetables, cucurbits, and fruits.

Health Risk Assessment and Multivariate Statistical Analysis of Heavy Metals in Vegetables of Khyber Pakhtunkhwa Region, Pakistan.

The level of heavy metals in vegetables grown in soil irrigated with various sources of water and the health risks associated with the consumption of these vegetables were assessed in this study. Samples of water, soil, and vegetables were collected from farmer fields. After digestion in acidic solution, analytical measurements were made using an atomic absorption spectrophotometer. The mean concentration of Pb, Cr, Cd, Cu, Zn, Ni, Fe, and Mn in the soil of two sampling area were in the range from 60.00 to 84.00mgkg-1, 68.00 to 98.00mgkg-1, 1.60 to 2.60mgkg-1, 26.10 to 33.20mgkg-1, 22.60 to 30.80mgkg-1, 50.10 to 78.30mgkg-1, 420.00 to 471.00mgkg-1, and 270.20 to 340.50mgkg-1, respectively. Heavy metals in soil varied significantly at (P ≤ 0.001) among sampling area. The nine heavy metals were divided into two clusters for wastewater and soil, according to cluster analysis. The number of variables was reduced using principal component analysis, which yielded three latent factors, one for wastewater and one for soil. Pb, Cr, Cd, Cu, Zn, Ni, Fe, and Mn concentrations were significantly higher at P ≤ 0.001 in nine vegetables grown on soil irrigated with untreated wastewater than in vegetables grown on fresh-tube well-water-irrigated soil. The health risks associated with metal intake were assessed using the estimated daily intake of metals (EDIM), hazard quotients (HQs), and hazard index (HI). The rates of metal transfer to vegetables have been determined. Except for Pb and Cd, all of the elements' EDMI values were found to be lower than their RfD values. The corresponding HRI values of metals in the various vegetables were found to be below 1, implying that vegetable consumption in the studied region poses no carcinogenic risk. Constant determination of heavy metals in all fruits and vegetables is essential for the assessment of health risks associated with dietary metal exposure. The study has provided valuable information to the general public about the use of wastewater for irrigation of vegetables.

Variation in Trace Minerals Content (Zn, Cd, As, Pb, Mn, Cr) of Irrigation Water, Soil and Vegetables Along Shagari Quarters Irrigation Site of Kano State

This work involves studying the variations of trace mineral contents (Zn, Cd, As, Pb, Mn and Cr) of irrigation water, soil and vegetables at shagari quarters irrigation site of Kano State of Nigeria between the months of June to December 2020. The irrigation water, Soil and vegetables samples were collected from shagari quarters irrigation site and analyzed using Standard analytical methods. The result of the analysis revealed that the concentrations (ppm) of the minerals ranged from Zn (0.71 to 1.75 for sample 5 to sample 2), Cd (0.00 to 0.003 for samples 3, 4, 5, 6, 7, 8 and to 2), As (0.00 to 0.48 for samples 6, 7, 8 and 9 to 2), Pb (0.00 to 0.008 for samples 3, 4, 5, 6, 7, 8 and to 1 and 2), Mn (0.11 to 1.50 for sample 4 to 2) and Cr (0.05 to 0.34 for sample 4 to 5 and 9). The minerals analysed are within the specification set by National Agency for Foods, Drugs Administration and Control (NAFDAC) and as such the Shagari quarters irrigation site as at June to December 2022 is not polluted and the crops are safe for human consumption. However, continuous monitoring is required.

Determination of Heavy Metals in Soil and Some Selected Vegetables Irrigated with Waste Water Along Asikolaye Stream Kaduna, Nigeria

Determination of Heavy Metals in Soil and Some Selected Vegetables Irrigated with Waste Water Along Asikolaye Stream Kaduna, Nigeria

Assessment of heavy metal concentrations in waste water irrigated vegetables

Shortage of good quality irrigation water in present changing scenario of climate forces farmers to use waste water for growing vegetables in urban and peri-urban areas which resulted in buildup of heavy metal in the food chain. Three commonly grown vegetables of city Multan; Onion, Brinjal and Tomato irrigated with waste water were selected to examine the heavy metal contents. The vegetables samples were collected from Haji Block Industrial Estate areas irrigated by waste water due to shortage of canal water. Total thirty samples of three vegetable were collected and analyzed. The results showed that the vegetable samples were contaminated with Pb, Cd and Ni. This study suggests that in future, waste water should be used after treatment to save the health of the masses. The re-use of waste water will help in proper management of soil health and will also save the soil water resources under present climatic conditions.

Prevalence of Pharmaceuticals in Surface Water Samples in Ghana

Pharmaceuticals, among the emerging contaminants, are pseudopersistent and recently of serious concern due to universal use, toxicity, and resistance development at low concentrations. This study was aimed at assessing the prevalence and risk of eight pharmaceuticals in surface water used for vegetable irrigation in Ghana’s Kumasi and Sunyani metropolises, which are influenced by hospitals, sewage treatment facilities, and market effluents. Samples were concentrated via solid-phase extraction (SPE) while liquid chromatography was used to identify and quantify the analytes. Ibuprofen, acetaminophen, and diclofenac were the detected analgesics in this study, with concentrations stretching from below detection limit (not detected) to 319.0 ng/L, while amoxicillin, trimethoprim, and cefuroxime were the detected antibiotics with a concentration range of no detection to 840.0 ng/L. Based on the available long-term data, an environmental risk assessment was conducted. Because of the presence of ibuprofen, the lowest trophic level and fish were shown to be at risk. The estimated risk quotient values for antibiotics resistance were above 1 for all the antibiotics investigated in surface water impacted by the wastewater of hospitals and pharmaceutical companies’ except surface water impacted by sewage treatment plants (STPs) and market wastewater. The existence of these pharmaceuticals in surface water does not only point to a general concern for the environment but also a potential health risk on humans and other lives as a result of their impact on drinking water and vegetable production in Ghana.

Possibilities of drip irrigation of vegetables in agricultural land of Uzbekistan

Reducing water consumption in crop irrigation in the world agriculture, studying soil moisture and water consumption by different irrigation methods, improving soil agrophysical properties and increasing productivity, as well as increasing the productivity of vegetable crops by various irrigation methods and improving phytosanitary conditions (weed and pest density, disease). Extensive research is being conducted to assess the level of one of the most pressing issues in agriculture is the development, improvement and widespread introduction of cost-effective irrigation methods in the spring and summer planting and care of vegetable crops in conditions of water scarcity.

Physico-chemical and bacteriological characterisation of surface water in Bamenda (North West Cameroon)

The Mezam River and its tributaries constitute a prominent water source for domestic use and vegetable irrigation in Bamenda Town (North West Cameroon). The river flows through the city and is thus vulnerable to impairment by substances from point and non-point sources. This current research aims to assess the degree of pollution of the Mezam River water to ascertain its suitability for various uses. A total of 24 water samples were collected from six segments of the Mezam River basin in the dry and rainy seasons during the years 2015 and 2016 in view of physico-chemical and bacteriological analyses. In situ measurement of physical parameters was taken in the field. The data were analysed by multivariate statistical techniques (principal component analysis and factor analysis). The results revealed that the river water is slightly acidic (pH = 5.45–6.47) and ion concentration is low (41.67–237.00 µS/cm). The water type is Ca-SO4 and Ca-Mg-(Cl + NO3) in the dry season and Ca-Mg-SO4 in the rainy season. High NO3− values (50 mg/l) are recorded at Nkimefueh. The Mezam River water is heavily polluted with indicator bacteria (0–500 CFU/100 ml) whose concentrations steadily increase from the reference point (YB) through sampling points in the city centre, suggesting the influence of human-induced activities. The population is urged to adopt a responsible behaviour towards waste disposal and refrain from disposing waste in water courses in order to safeguard the aquatic environment and also protect the health of the population.

Diverse biosphere influence on carbon and heat in mixed urban Mediterranean landscape revealed by high resolution thermal and optical remote sensing

A fundamental challenge in verifying urban CO2 emissions reductions is estimating the biological influence that can confound emission source attribution across heterogeneous and diverse landscapes. Recent work using atmospheric radiocarbon revealed a substantial seasonal influence of the managed urban biosphere on regional carbon budgets in the Los Angeles megacity, but lacked spatially explicit attribution of the diverse biological influences needed for flux quantification and decision making. New high-resolution maps of land cover (0.6 m) and irrigation (30 m) derived from optical and thermal sensors can simultaneously resolve landscape influences related to vegetation type (tree, grass, shrub), land use, and fragmentation needed to accurately quantify biological influences on CO2 exchange in complex urban environments. We integrate these maps with the Urban Vegetation Photosynthesis and Respiration Model (UrbanVPRM) to quantify spatial and seasonal variability in gross primary production (GPP) across urban and non-urban regions of Southern California Air Basin (SoCAB). Results show that land use and landscape fragmentation have a significant influence on urban GPP and canopy temperature within the water-limited Mediterranean SoCAB climate. Irrigated vegetation accounts for 31% of urban GPP, driven by turfgrass, and is more productive (1.7 vs 0.9 μmol m−2 s−1) and cooler (2.2 ± 0.5 K) than non-irrigated vegetation during hot dry summer months. Fragmented landscapes, representing mostly vegetated urban greenspaces, account for 50% of urban GPP. Cooling from irrigation alleviates strong warming along greenspace edges within 100 m of impervious surfaces, and increases GPP by a factor of two, compared to non-irrigated edges. Finally, we note that non-irrigated shrubs are typically more productive than non-irrigated trees and grass, and equally productive as irrigated vegetation. These results imply a potential water savings benefit of urban shrubs, but more work is needed to understand carbon vs water usage tradeoffs of managed vs unmanaged vegetation.

Results and prospects of the Astrakhan selection of vegetable and melon crops

Relevance. Since the increasing demand for agricultural products, especially at present in the conditions of import substitution, cannot be met without creating new highly productive varieties and hybrids.Material and methods. This article provides a description and comparative characteristics of economically valuable qualities and varieties of vegetable crops, the most common and in demand among the population, created by breeders of the All-Russian Research Institute of Irrigated Vegetable Growing and Melon Growing – a branch of the FSBSI "PAFSC RAS". The experiments were laid on the experimental fields.Results. As a result of many years of breeding work presented varieties belong to different variety types, they differ in groups of precocity, shape, size, color of fruits. Tomatoes – Astrakhan, Bulldog, Avdeevsky, Caspian, Malinovi shar, Moryana, Rychansky, Forward, Orange Avuri, Malinovi Supergol, etc. Varieties of sweet pepper – Atomor, Marble, Novichok VNIIOB, Sprinter, Lyudmila, etc. Varieties of eggplant – Albatross, Diamond, Astrakom, Nizhnevolzhsky, Swan, etc. Since 2021, the Gnomik tomato variety has been entered into the State Register, and the Zarnitsa sweet pepper variety is being tested. The Astrakhan region is also a center for the creation and production of melon crops, their fruits belong to dietary products, are used both fresh and for preservation, preparation of drinks, desserts, home cooking. Watermelon varieties – Astrakhan, Photon, Ilyasovsky, Portioned; melon – Lada, pumpkin – Kroshka and Kapelka, zucchini – Sosnovsky and Jubilee, squash – Tabolinsky.

First detection of diarrheagenic Escherichia coli pathotypes in the Mearim River Watershed, Maranhão State, Brazil

The Mearim River Watershed has multiple uses e.g. leisure, navigation, fishing and subsistence agriculture and constitutes the main source of supply for the populations of municipalities situated along its course. In addition to being a water supply source, the existence of the ‘pororoca’ (tidal bore) effect in a stretch of the lower course of the Mearim River attracts people from several Brazilian states and different countries, as it offers excellent conditions for surfing in fresh water. In this respect, given the importance of the watershed, this study was developed to report the detection of diarrheagenic Escherichia coli pathotypes in a stretch of the lower course of the Mearim River, located in the state of Maranhão, Brazil. Thirty water samples were collected from 10 sampling points. To quantify E. coli, the chromogenic enzymatic system was used and positive samples were isolated and biochemically identified. Pure cultures underwent DNA extraction by heating followed by polymerase chain reaction (PCR) characterization. At the time of the collections, an observation schedule was used to record information on the existence of rearing of livestock and domestic animals; businesses; residences; and fruit and vegetable farming on the riverbanks. The samples were analyzed for the mean populations of E. coli, which ranged from 444 to 2,585 MPN mL-1. Twenty bacterial isolates were identified and the diarrheal pathotypes ETEC, typical EPEC and atypical EPEC were detected. The detection of these pathotypes can represent an epidemiological risk and compromise several uses of this water resource, such as irrigation of fruits and vegetables consumed raw, fishing, animal watering and recreation. Structural investments in basic sanitation are essential to minimize environmental degradation resulting from anthropic activities and to act preventively in public health. In addition, the recovery of riparian forests along the watershed and the maintenance of vegetation in these areas are measures to reduce the transport of particles from the soil to the watercourses, improving the qualitative and quantitative characteristics of this water resource.

Tracking Fecal Bacterial Dispersion from Municipal Wastewater to Peri-Urban Farms during Monsoon Rains in Hue City, Vietnam.

Disease outbreaks attributed to monsoon flood-induced pathogen exposure are frequently reported, especially in developing cities with poor sanitation. Contamination levels have been monitored in past studies, yet the sources, routes, and extents of contamination are not always clear. We evaluated pollution from municipal wastewater (MWW) discharge and investigated fecal contamination by Escherichia coli (E. coli) in three agricultural fields on the outskirts of Hue City, Vietnam. After E. coli concentration was determined in irrigation water (IRW), MWW, soil, vegetables (VEG), and manure, its dispersion from MWW was tracked using multilocus sequence typing (MLST) and phylogenetic analyses during the wet and dry seasons. IRW was severely contaminated; 94% of the samples were positive with E. coli exceeding the stipulated standards, while VEG contamination was very low in both seasons. The confirmed total number of isolates was comparable between the seasons; however, results from MLST and phylogenetic clustering revealed more links between the sites and samples to MWW during the wet season. The wet season had four mixed clusters of E. coli isolates from multiple locations and samples linked to MWW, while only one mixed cluster also linking MWW to IRW was observed during the dry season. The most prevalent sequence type (ST) complex 10 and two others (40 and 155) have been associated with disease outbreaks, while other STs have links to major pathotypes. Irrigation canals are significant routes for E. coli dispersion through direct links to the urban drainage-infested river. This study clarified the genotype of E. coli in Hue city, and the numerous links between the samples and sites revealed MWW discharge as the source of E. coli contamination that was enhanced by flooding.

THE GROWING TECHNOLOGY OF MIXED SEEDED PLANTS AT STUBBLE-FIELD

One of the main measures to increase production in the field of grain and feed production in our republic is to increase the yield of grain and forage crops on plantations.The purpose of our research work is to study the effect of fertilization and irrigation rates on the yield, crop quality and soil fertility of crops sown in a mixture when planting honeysuckle. The results of research conducted in world agriculture show that mainly the yield and composition of mixed crops, the quality indicators of which depend on the components of the crops to be sown, their seeding rate and cultivation technology. As a result of studies conducted in the conditions of ancient irrigated gray-meadow soils of the Karabakh region of our republic, it was found that with 4 - fold vegetation irrigation (4200 m3), the yield of mixed sowing in the control version without fertilizers was 372 c/ha, while under the influence of mineral and organic mineral fertilizers, the yield increased and amounted to 447-627 c/ha. Based on the results of the study, it can be said that in order to obtain a high yield of green mass with the joint sowing of corn and soybeans, the optimal irrigation and fertilizer application rates were determined, the highest indicator was achieved in the variant where the fertilizer standards N120P150C150 were applied. In the course of the study, the influence of fertilizer application rates and optimization of the amount of irrigation on the quality indicators of feed, as well as on the yield obtained from mixed crops, was studied. As a result of the conducted analyses, the amount of raw protein, absolute dry matter, nitrate nitrogen in the natural mass, the yield of feed units per hectare and the amount of protein going for digestion were determined. Thus, the application of fertilizers within the optimal limits and the correct, timely supply of irrigation standards significantly increase the quality of the crop on a par with the yield on mixed crops, the soil fertility is preserved.

Water quality for agriculture use in Jequetepeque middle river basin, Peru

This research had the main objective to determine water quality for agriculture use in Jequetepeque middle basin river, Peru. Six sampling station were located (Kuntur Wasi bridge, La Monica sector, La Capilla sector, Yatahual village, El Pongo village and Yonan bridge). The physical-chemical, bacteriological parameters and SAR index was determined. The water quality in the study area was found within the Water Quality Standards by Supreme Decree N°004-2017-MINAM, according to Category 3: vegetable irrigation and animal drink, and D1: vegetable irrigation, it used without restrictions for different crops. It is important in relation to bacteriological assessment, the average values of thermotolerant coliforms exceeded water quality (1 000 NMP/100 ml) and indicating low organic pollution as consequence of the contributions or discharges of domestic origin. The SAR index found values lower than 3, therefore it is not limiting for agricultural activity. It is great importance to carry out water quality studies of all river basin in the country, especially to assess water quality for irrigation due to potential effect on human health and ecosystem conservation.

Pathogen and heavy metal contamination in urban agroecosystems of northern Ghana: Influence of biochar application and wastewater irrigation.

The benefit of biochar as a soil fertility enhancer is well known and has been broadly investigated. Equally, many tropical and subtropical countries use wastewater for irrigation in urban agriculture. To assess the related health risks, we determined pathogen and heavy metal fate associated with biochar application and wastewater irrigation in the urban agriculture of northern Ghana. Rice (OryzaL.) husk biochar (20 t ha-1 ), N-P-K 15-15-15 fertilizer (212.5kg ha-1 ), and their combinations were evaluated in a field-based experiment. Untreated wastewater and tap water served as irrigation water. Red amaranth (Amaranthus cruentus L.) was used as a test crop and was grown in wet (WS) and dry (DS) cropping seasons. Irrigation water, soil, and vegetables were analyzed for heavy metals, Escherichia coli, fecal coliform, helminth eggs, and Salmonella spp. Unlike the pathogens, analyzed heavy metals from irrigation water and soil were below the FAO/WHO permissible standard for agricultural activities. Wastewater irrigation caused E. coli concentrations ranging from 0.5 to 0.6 (WS) and from 0.7 to 0.8 (DS) log10 colony forming units per gram fresh weight (CFU gFW -1 ) on vegetables and from 1.7 to 2.1 (WS) and from 0.6 to 1.0 (DS) log10 CFU per gram dry weight (gDW -1 ) in soil. Average log10 CFU gFW -1 rates of 6.19 and 3.44 fecal coliform were found on vegetables, whereas in soil, 4.26 and 4.58 log10 CFU gDW -1 were observed in WS and DS, respectively. Helminth egg populations were high in wastewater and were transferred to the crops and soil. Biochar did not affect bacteria contamination. Pathogen contamination on vegetables and in soil were directly linked to the irrigation water, with minimal or no difference observed from biochar application.

Uptake of Arsenic by Irrigated Vegetables and Cooked Food Products in Burkina Faso

As compared to the Asian lowlands, environmental exposure to arsenic (As) in West Africa has received little attention. Recent studies have found geogenic As contamination of groundwater in many regions in Burkina Faso. As-contaminated groundwater is used for drinking and increasingly also for the irrigation of staple foods. This study assesses the extent to which irrigation and cooking of staple foods in Burkina Faso influence plant uptake and dietary consumption of As, respectively. Using a greenhouse experimental setup, we evaluated the transfer of As from irrigation water spiked with 0, 100, 500, and 1,000 μg/L As(V) to the organs and edible parts of seven commonly consumed vegetables (amaranth, carrot, green bean, lettuce, okra, spinach, and tomato). Next, we cooked the greenhouse-cultivated vegetables and externally purchased foods with As-free and As-spiked waters. The As content in all plant organs increased with increasing As in the irrigation water. With 500 μg/L, the concentrations of As in the edible parts (ordered from highest to lowest) were as follows: spinach (6.6 ± 0.5 μg/g); lettuce (3.9 ± 0.1 μg/g); carrot (3.5 ± <0.1 μg/g); amaranth (2.2 ± <0.1 μg/g); okra (0.9 ± <0.1 μg/g); green bean (0.8 ± <0.1 μg/g); and tomato (0.2 ± <0.1 μg/g). The edible parts of leafy vegetables irrigated with As-spiked water had a higher average As content (4.9 ± 4.5 μg/g) than root (2.9 ± 2.0 μg/g) and fruit/pod vegetables (0.8 ± 1.1 μg/g). Cooking with an excess volume of As-free water reduced the As content in the cooked vegetables by 39% on average, while cooking with As-contaminated water transferred As to the cooked food. The As content in steamed foods was 8 to 18 times lower than in boiled foods. Based on human health risk estimates, we generally recommend to avoid planting leafy and root vegetables in areas with As concentrations above 100 μg/L in irrigation water. In areas with elevated As contamination, mitigation strategies include the cultivation of fruit/pods vegetables such as tomato and okra and steaming the food instead of boiling.

HEAVY METALS IN THE FOOD CHAIN - CONSEQUENCES OF POLLUTING WATER BODIES

Purpose of the study: Heavy metals in food (vegetables, etc.) are harmful to humans due to their non-biodegradable nature, long biological half-lives, and their potential to accumulate in different body parts. Prolonged consumption of such heavy metal contaminated vegetables through foodstuffs may lead to chronic accumulation of heavy metals in human beings' kidneys and liver, disrupting numerous biochemical processes, leading to cardiovascular, neural, kidney and bone diseases. Method: The study on heavy metal concentrations in vegetables grown in the command areas of Varthur lake, Bangalore. The collected vegetable samples were analyzed using ICP-OES (Inductively Coupled Plasma-Optical Emission Spectroscopy) technique to assess the level of heavy metal in acid digested samples. Main Findings: The study has shown a significant accumulation of heavy metals in vegetables that correlated well with its concentrations in soil and lake water. The prolonged irrigation of vegetables using contaminated lake water has led to soil contamination, which ultimately resulted in contamination of vegetables due to the uptake and accumulation of heavy metals in edible portions of vegetables. Application of the Study: Urgent attention is needed to devise and implement appropriate means of regular monitoring of the toxic heavy metals from domestic sewage and industrial effluent and provide proper advice and support for the safe and productive use of wastewater for irrigation purposes to prevent excessive buildup of heavy metals in the food chain.

Impact of repeated irrigation of lettuce cultures with municipal wastewater on soil bacterial community diversity and composition.

The effect of wastewater irrigation on the diversity and composition of bacterial communities of soil mesocosms planted with lettuces was studied over an experiment made of five cultivation campaigns. A limited effect of irrigation with either raw or treated wastewater was observed in both α-diversity and β-diversity of soil bacterial communities. However, the irrigation with wastewater fortified with a complex mixture of fourteen relevant chemicals at 10 μg/L each, including pharmaceutical, biocide, and pesticide active substances, led to a drift in the composition of soil bacterial community. One hundred operational taxonomic units (OTUs) were identified as responsible for changes between treated and fortified wastewater irrigation treatments. Our findings indicate that under a realistic agronomical scenario, the irrigation of vegetables with domestic (treated or raw) wastewater has no effect on soil bacterial communities. Nevertheless, under the worst-case scenario tested here (i.e., wastewater fortified with a mixture of chemicals), non-resilient changes were observed suggesting that continuous/repeated irrigation with wastewater could lead to the accumulation of contaminants in soil and induce changes in bacterial communities with unknown functional consequences.

Comparative Analysis of Trace Elements Found in Commonly Used Vegetables Irrigated By Fresh And Waste Water in Karachi, Pakistan

Use of municipal waste water (both treated and untreated) has now become a common practice in urban and peri-urban areas. Mostly vegetables in urban cities like Karachi are being irrigated by sewerage water. In this study a comparison of sewage and fresh water-irrigated vegetables has been made with respect to trace metals. Among commonly used vegetables, green onion, cabbage, pumpkin, eggplant, bird’s eye chili and okra were selected. Two sets of these vegetables were collected, one from local farm where irrigation was done with well water and other set of samples was collected from Malir, Karachi where irrigation was done with waste water. Samples were analyzed for heavy metals i.e. K, Na, Pb, Zn, Cu, Cd, Fe, and As by Atomic Absorption Spectroscopy. It showed that both sets of samples were found to contain metal concentrations beyond the limits set by WHO/EU. Apart from tomato, the concentration of only Cd was near the standard value for both sets. Similar results were obtained for K except for pumpkin in which the concentration for waste water irrigated samples was fairly high. Amount of Cu and Fe were moderately higher than the standard in both samples. Arsenic in all the samples was considerably high while maximum concentration was obtained for Pd against the limits. These findings suggest waste water irrigated vegetables pose high risk to human health. The concentrations of As and Pb were high in fresh water samples possibly, the well water may contain metals, therefore it is important to know the source.