Human health risks from consuming cabbage (Brassica oleracea L. var. capitata) grown on wastewater irrigated soil

Assessment of heavy metal accumulation and health risk in three essential edible weeds grown on wastewater irrigated soil

The main problem facing Egypt recently is the shortage of available water resources. Therefore, farmers resort to use wastewater for irrigation. So, the present work aims to assess the impacts of wastewater irrigation on the productivity of three edible weeds (Cichorium endivia, Sonchus oleraceous and Beta vulgaris) and its effect on the nutritional value of plants and its risk on human health. This study will focus on Shibin Al Kanater region, and the physicochemical characteristics of drainage water, canal water, drainage water-irrigated soils and canal-irrigated soils were estimated. The vegetative and traits of edible weeds were determined including their photosynthetic pigments, organic and inorganic nutrients content, and heavy metals content. The health risk index (HRI) associated with consumption of polluted plants was created using the estimated exposure factor of a crop to the oral reference dosage of the toxic metal. The main results showed that biomass productivity of S. oleraceous, B. vulgaris and C. endivia increased due to drainage water irrigation with increasing percentage as 27.9, 19.6, and 19.1%, respectively. Irrigation with drainage water significantly increased the photosynthetic pigments of edible weeds. Irrigation with drainage water increased carbohydrate content, crude protein, total soluble sugar, and gross energy in all studied weeds. C. endivia, S. oleraceus and B. vulgaris plants irrigated with canal and drainage water could accumulate Fe, Zn, Cu, and Co in their roots. C. endivia, S. oleraceus and B. vulgaris plants irrigated with canal water indicated HRI more than the unit for Mn, Cu, Pb, and Cd. This research advises that regulation be put in place to prohibit irrigation using untreated drainage and to restrict the discharge of industrial, domestic, and agricultural wastewater into irrigation canals.

Acinetobacter schindleri SR-5-1 decipher morpho-physio-biochemical and nutritional improvements to Pisum sativum L. and Linum usitatissimum L. maintained under wastewater/cadmium stress

Metal retention in wastewater fertigated crops poses a potential hazard to food chain. Current work demonstrates the bioremediation and growth-promoting potential of Acinetobacter schindleri SR-5-1 by using nitrogen-fixing (pea) and non-nitrogen fixing (linseed) plants under cadmium (Cd) and wastewater irrigation regimes. Both plants were grown at 250 or 500 CdCl2 and 75 or 100% wastewater, each separately with and without A. schindleri SR-5-1 inoculation. The results revealed that Cd and wastewater significantly decreased growth, biomass, antioxidants, and nutrient acquisition through increased malondialdehyde, H2O2, and Cd accumulation. However, application of A. schindleri SR-5-1 significantly promoted morpho-physio-biochemical attributes while diminishing MDA and H2O2 under applied Cd and wastewater stress levels in both pea and linseed. Further, PGPR inoculation positively influenced pea and linseed seedlings through a substantial decline in Cd accumulation in roots/shoots and retained the optimal level of essential nutrients. It was inferred that both pea and linseed, with A. schindleri SR-5-1 application, exhibited higher growth and metabolism under Cd and wastewater stress but substantial tolerance was acquired under wastewater stress. Studied plants exhibited tolerance in order of 75% WW ≥ 250 µM Cd ≥ 100%WW ≥ 500 µM Cd treatment under A. schindleri inoculation. Current findings revealed the potential of A. schindleri to be exploited both for bioremediation and bio-fertilization under Cd, and wastewater-polluted regimes to reduce metal contamination of edible plants. It was suggested that with inoculation of A. schindleri SR-5-1, 75% WW dilution can be applied for irrigation of both nitrogen-fixing and non-nitrogen-fixing crops.

Diversity of Bacterial Soft Rot-Causing Pectobacterium Species Affecting Cabbage in Serbia

The aim of this work was to identify and characterize the pectolytic bacteria responsible for the emergence of bacterial soft rot on two summer cabbage hybrids (Cheers F1 and Hippo F1) grown in the Futog locality (Bačka, Vojvodina), known for the five-century-long tradition of cabbage cultivation in Serbia. Symptoms manifesting as soft lesions on outer head leaves were observed during August 2021, while the inner tissues were macerated, featuring cream to black discoloration. As the affected tissue decomposed, it exuded a specific odor. Disease incidence ranged from 15% to 25%. A total of 67 isolates producing pits on crystal violet pectate (CVP) medium were characterized for their phenotypic and genotypic features. The pathogenicity was confirmed on cabbage heads. Findings yielded by the repetitive element palindromic-polymerase chain reaction (rep-PCR) technique confirmed interspecies diversity between cabbage isolates, as well as intraspecies genetic diversity within the P. carotovorum group of isolates. Based on multilocus sequence typing (MLST) using genes dnaX, mdh, icdA, and proA, five representative isolates were identified as Pectobacterium carotovorum (Cheers F1 and Hippo F1), while two were identified as Pectobacterium versatile (Hippo F1) and Pectobacterium odoriferum (Hippo F1), respectively, indicating the presence of diverse Pectobacterium species even in combined infection in the same field. Among the obtained isolates, P. carotovorum was the most prevalent species (62.69%), while P. versatile and P. odoriferum were less represented (contributing by 19.40% and 17.91%, respectively). Multilocus sequence analysis (MLSA) performed with concatenated sequences of four housekeeping genes (proA, dnaX, icdA, and mdh) and constructed a neighbor-joining phylogenetic tree enabled insight into the phylogenetic position of the Serbian cabbage Pectobacterium isolates. Bacterium P. odoriferum was found to be the most virulent species for cabbage, followed by P. versatile, while all three species had comparable virulence with respect to potato. The results obtained in this work provide a better understanding of the spreading routes and abundance of different Pectobacterium spp. in Serbia.

Phytoaccumulation of zinc and its associated impact on the growth performance and tolerance index of six non-food crop plants grown in Zn-contaminated soil

Crop plant remediation and detoxification of Zn-contaminated soils may pose a significant threat to food safety and, thus, human health. Therefore, the current study was carried out to assess the ability of six non-food crop plants (NFCP); Zea mays L. cultivar 360 (T360), Z. mays cultivar 123 (T123), Helianthus annuus L., Brassica juncea (L.) Czern., Ricinus communis L., and Simmondsia chinensis (Link) C.K. Schneid to remediate and restore Zn-contaminated soils. The investigated plants tolerate 150 mg/kg of Zn content of the soil, where they had tolerance index (TI) > 1 for all growth criteria, except the root dry weight (DW) of S. chinensis. Z. mays T123 and R. communis were the most susceptible plants, while B. juncea and S. chinensis were moderately tolerant, while H. annuus was the most tolerant to high Zn concentrations in a growing medium. Increasing the soil Zn content led to a significant increase (p < 0.05) in Zn concentration in the various tissues of the six NFCPs. The studied NFCP did not translocate Zn to their grains/seeds; consequently, they can be used safely for Zn-contaminated soils. The Zn content in root and shoot was negatively correlated with the TI of their length and weight, while the translocation factor (TF) of Zn from root to shoot was positively correlated to the TI of the root length and weight. The six studied NFCPs were arranged based on their phytoremediation efficiency as follows: B. juncea (31.86%) > Z. mays T123 (31.14%) > Z. mays T360 (27.59%) > H. annuus (20.85%) > S. chinensis (20.29%) > R. communis (15.3%). All tested NFCPs accumulated significant concentrations of Zn in their roots and shoots, a high Zn uptake potential, and biomass at 150-450 mg/kg of Zn treatments, indicating that these plants are good candidates for the implementation of a new strategy of cultivating NFCP for phytoremediation of Zn-contaminated soils.

Safety assessment and sustainability of consuming eggplant (Solanum melongena L.) grown in wastewater-contaminated agricultural soils

Vegetables cultivated on contaminated agricultural soils are being consumed by the public, and consequently cause serious health concerns due to contaminants' dietary intake. The current study examines the safety and sustainability of eating eggplant (Solanum melongena) by looking into the possibility of heavy metals translocation from polluted soils to the edible sections, as well as the health hazards that come with it. Soil and eggplant samples were taken from three contaminated and other three uncontaminated farms to estimate their chemical constituents and plant growth properties. Based on the pollution load index data, the contaminated soils were highly polluted with Fe, Cu, Pb, and Zn; and relatively polluted with Cr, Mn, Cd, Mn, Co, and V. Under contamination stress, the fresh biomass, dry biomass, and production of eggplant were significantly reduced by 41.2, 44.6, and 52.1%, respectively. Likewise, chlorophyll a and b were significantly reduced from 1.51 to 0.69 mg g⁻¹ and 1.36 to 0.64 mg g⁻¹, respectively. The uncontaminated plant shoots had the highest quantities of N, P, and proteins (1.98, 2.08, and 12.40%, respectively), while the roots of the same plants had the highest K content (44.70 mg kg⁻¹). Because eggplant maintained most tested heavy elements (excluding Zn and Pb) in the root, it is a good candidate for these metals' phytostabilization. However, it had the potential to translocate Mn and Zn to its shoot and Pb, Cr, Mn, and Zn to the edible fruits indicating its possibility to be a phytoextractor and accumulator of these metals. Cd, Cu, Ni, Pb, Mn, and Co quantity in the edible sections of eggplant grown in contaminated soils exceeded the permissible level for normal plants, posing health hazards to adults and children. For safety issues and food sustainability, our investigation strongly recommends avoiding, possibly, the cultivation of eggplant in contaminated agricultural lands due to their toxic effects even in the long run.

Accumulation and translocation of eight trace metals by the different tissues of Abelmoschus esculentus Moench. irrigated with untreated wastewater

Due to water scarcity, the use of wastewater to irrigate crops is on the rise all over the world, including in Egypt (particularly untreated wastewater). The purpose of this study is to see if irrigation with untreated industrial wastewater in natural fields can cause Abelmoschus esculentus Moench. (okra plant) to accumulate and translocate eight trace metals (lead: Pb, cadmium: Cd, chromium: Cr, copper: Cu, iron: Fe, manganese: Mn, nickel: Ni, and zinc: Zn) in its different tissues. It was extended to look at the effects of wastewater irrigation on the farmed okra plants' growth characteristics, nutrients, colors, and organic content. Two studied sites at South of Cairo have been investigated: the first site (29°42'31.17" N and 31°15'11.56" E) represented by five cultivated fields irrigated with Nile water (control) and the second site (29°42'37.87" N and 31°17'14.53" E) fields irrigated with effluent received untreated industrial wastewater. Three composite soil and irrigated water samples were collected from each site. Because of wastewater irrigation, soil and plant nutrients (nitrogen, potassium, and phosphorus) decreased significantly (at P < 0.01), whereas trace metals increased significantly (at P < 0.01 and P < 0.05) for soil and plant samples irrigated with untreated wastewater. Due to irrigation with untreated wastewater, there was also a significant decrease in okra growth metrics (at P < 0.05) and leaves photosynthetic pigments: chlorophyll a and b, and carotenoids (at P < 0.01 and P < 0.05). In the plant's fruits (edible section) watered with wastewater, iron was the most abundant metal. Besides, Cd, Cu, Fe, Mn, Ni, and Zn concentrations were also in the phytotoxic range (42.57, 140.67, 2756.67, 1293.33, 1326.67, and 877.83 mg kg^-1, respectively). All trace elements examined accumulate in the roots of wastewater irrigated okra (Bioaccumulation factor > 1). Okra plants, on the other hand, did not have an accumulated trace metals strategy in their shoots since the translocation factor was less than one. Because of substantial trace metal accumulation in their edible sections, the scientists advised against eating okra plants grown in fields watered with untreated wastewater.

Effect of Marginal-Quality Irrigation on Accumulation of some Heavy Metals (Mn, Pb, and Zn) in TypicTorripsamment Soils and Food Crops

Lack of active sorption sites in sandy soils renders metals added by irrigation water more labile and increases their soil-to-plant transfer. Thus, this study investigated the long-term impacts of irrigation using sewage effluents and contaminated groundwater on metal accumulations in TypicTorripsamment soils, and edible parts of food crops. Nine sites in El-Gabal El-Asfar farm, south-eastern to the Nile Delta of Egypt, were selected. At each site, irrigation water, soil (0–30 cm), and the crop’s edible part were sampled in triplicates and analyzed for Mn, Pb, and Zn. Results revealed significant (p < 0.05) differences in metal concentrations among water sources. Thus, constant irrigation caused significant spatial variations in total and available metal contents in soils. Total contents of Pb (in four sites) and Zn (in all sites) exceed the lithosphere range, while the available contents of the three metals exceeded the safe limits in all soils. The index of geo-accumulation indicated no Mn pollution but showed elevated pollution risks for Pb and Zn. The three metals showed high availability ratios, proving the effect of light soil texture. The multivariate statistical analysis indicated that Mn and Zn had similar geochemical behaviors in soils. Metal contents in all crop’s edible parts surpassed the safe limits. The bioaccumulation factor (BAF) was less than 1.0 for Mn and Zn but higher than 1.0 for Pb. The highest BAFs occurred in cabbage leaves, indicating the phytoextraction potential of this species. Sufficient water treatment and proper remediation techniques are recommended to alleviate metal accumulation in food crops and their transfer via the food chain.

Heavy metals uptake by the global economic crop (Pisum sativum L.) grown in contaminated soils and its associated health risks

The aim of the present investigation was to determine the concentration of heavy metals in the different organs of Pisum sativum L. (garden pea) grown in contaminated soils in comparison to nonpolluted soils in the South Cairo and Giza provinces, Egypt, and their effect on consumers' health. To collect soil and plant samples from two nonpolluted and two polluted farms, five quadrats, each of 1 m2, were collected per each farm and used for growth measurement and chemical analysis. The daily intake of metals (DIM) and its associated health risks (health risk index (HRI) were also assessed. The investigated heavy metals were cadmium (Cd), arsenic (As), chromium (Cr), copper (Cu), nickel (Ni), iron (Fe), manganese (Mn), zinc (Zn), silver (Ag), cobalt (Co) and vanadium (V). Significant differences in soil heavy metals, except As, between nonpolluted and polluted sites were recorded. Fresh and dry phytomass, photosynthetic pigments, fruit production, and organic and inorganic nutrients were reduced in the polluted sites, where there was a high concentration of heavy metals in the fruit. The bioaccumulation factor for all studied heavy metals exceeded 1 in the polluted sites and only Pb, Cu and Mn exceeded 1 in the nonpolluted sites. Except for Fe, the DIM of the studied heavy metals in both sites did not exceed 1 in either children or adults. However, the HRI of Pb, Cd, Fe, and Mn in the polluted plants and Pb in the nonpolluted ones exceeded 1, indicating significant potential health risks to consumers. The authors recommend not to eat garden peas grown in the polluted sites, and farmers should carefully grow heavy metals non-accumulating food crops or non-edible plants for other purposes such as animal forages.

Seasonal variation of potentially toxic metal contamination in Yamuna riverine ecosystem, Delhi, India

The River Yamuna in Delhi region, the National Capital Territory (NCT) of India, carries potentially toxic metals such as Cr, Pb, Mn, Mg, Hg, Fe and Zn. These contaminants are discharged mainly from industrial wastes, agricultural and household activities and domestic sewage. A total of 12 stations (2.5 to 3.5 km apart from each other) were selected for the study, covering the upstream and downstream areas of river Yamuna in Delhi. The investigated sites were evaluated for significant difference between upstream and downstream locations of river Yamuna in three different time periods (June, October, February). Metal contamination were measured in water, sediments (2 μm) and nearby agriculture soil of the river Yamuna, and found with high metal loads as compared with the international standards, chiefly in the downstream sites as the river flows through the Delhi stretch. The multivariate statistical analysis revealed spatial and temporal variations in the metal concentrations which suggest seasonal variation and common point source of some metals while different sources of other metals. The contamination of the river water and adjoining agriculture soils points towards possible entry of these metals into the food chain. The study indicates that considering the current status of metal pollution, the surface water is not in good conditions for use as drinking purpose because of the high concentrations of few potentially toxic metals. Our study recommends regular monitoring of toxic metals in Yamuna river water and sediments, strict ban on the domestic, agriculture and industrial waste disposal for the restoration of the river to its natural state.

Efficacy of two seaweeds dry mass in bioremediation of heavy metal polluted soil and growth of radish (Raphanus sativus L.) plant

This study investigated the effect of Ulva fasciata and Sargassum lacerifolium seaweeds as heavy metal remediators for soil and on the growth of radish (Raphanus sativus L.). The soil was inoculated by dry biomass of each seaweed alone and by their mixture. Seaweeds inoculation increased the organic matter content, clay-size fraction, and nutrients in the soil. Seaweeds mixture treatment caused a significant reduction in the contents of Pb, Cu, Zn and Ni in the soil samples and reduced them to the tolerable limits (40.2, 49.3, 43.8 and 1.1 mg kg^-1, respectively), while Cd, Cr, Fe, and Mn contents were closely decreased to the tolerable limits. Biosorption of soil heavy metals by seaweeds decreased the bioaccumulated concentrations of metals in radish plant roots and/or translocated to its shoots compared to control. For seaweeds mixture-treated soil, cultivated radish roots were able to phyto-extract Cd, Cu, Cr, and Ni from the soil (bioaccumulation factor values > 1) of 7.45, 1.18, 3.13, and 26.6, respectively. Seaweeds inoculation promoted the growth of cultivated radish and improved the germination percentage and the morphological and biochemical growth parameters compared to control plants. The achieved soil remediation by dried seaweeds might be due to their efficient metal biosorption capacity due to the existence of active functional groups on their cell wall surfaces. Increased growth observed in radish was as a result of nutrients and growth hormones (gibberellins, indole acetic acid, and cytokinins) present in dried seaweeds. This study shows the efficiency of seaweeds as eco-friendly bioremediators for controlling soil pollution.

Prediction models for monitoring heavy-metal accumulation by wheat (Triticum aestivum L.) plants grown in sewage sludge amended soil

Prediction of heavy-metal concentration in the edible parts of economic crops, based on their concentration in soil and other environmental factors, is urgently required for human risk assessment. The present investigation aimed to develop regression models for predicting heavy-metal concentration in wheat plants via their contents in sewage sludge amended soil, organic matter (OM) content and soil pH. The concentration of heavy metals in the plant tissues reflected its concentration in the soil with high Fe followed by Al, Mn, Cr, Zn, Ni, Co, Cu, and Pb. Soil OM content had a significant positive correlation with all investigated heavy-metal concentrations in the different tissues of wheat plants, while soil pH was negatively significant with most heavy metals except spike Pb and grain Cr. The bio-concentration factor of Al, Cu, and Zn from soil to wheat root was >1, while that of shoot, spikes, and grains was <1 for all heavy metals. Significantly valid regression models were developed with fluctuated coefficient of determination (R²), high model efficiency (ME) values and low mean normalized average error (MNAE). The significant positive correlations between the concentration of some heavy metals in the soil and the same in wheat tissues indicate the potential of this plant as a biomonitor for these metals in contaminated soils. The significant correlations between heavy-metal concentrations in soil and its properties (pH and OM) with metal concentrations in wheat plants support the prediction model as an appropriate option. This study recommends the use of models with R² greater than 50% and recommend other researchers to use our models according to their own specific conditions.

Hazards assessment of the intake of trace metals by common mallow (Malva parviflora K.) growing in polluted soils

Human risks increase by consuming plants growing in trace/heavy metals contaminated soil irrigated with polluted water. The present study aims to assess the ability of common mallow to accumulate trace/heavy metals from polluted soils at South Greater Cairo, Egypt; and their hazardous effects on consumer's health. Five quadrats were used to collect soil and plant samples from three sites of un-polluted and polluted fields for chemical analysis and measurement of growth variables, as well as for assessing the daily intake of metals (DIM) and hazard quotient (HQ). Irrigation water analysis showed elevated concentrations of the investigated metals and mineral salts in the polluted area compared with the un-polluted one. Plant samples showed reduction in their growth parameters; as well as pigments and nutrient content in the metal-contaminated soil. In addition, Pb, Cd, Cu, Ni, Fe, Mn, Zn, and Co concentrations in the shoots and roots of plants grown in polluted fields were higher compared with plants grown in un-polluted site. The bioaccumulation and translocation factors of most investigated metals indicated the great ability of common mallow to accumulate such metals, which would increase the human intake of metals in their daily diets compared to their reference values (R_fD). The hazard quotient (HQ) of Pb, Cr, Fe, Mn and Zn for children and Pb, Cd, Fe and Mn for adults was >1, indicating health hazards for the consumers of common mallow cultivated in the polluted area.