Com as mãos na terra: estratégias de promoção em nutrição agroecológica / Hands on earth: promotion strategies in agroecological nutrition

Introdução: É notório que a alimentação e a nutrição adequada constituem requisitos indispensáveis para a promoção e a proteção da saúde. Objetivo: Contribuir para a melhoria do acesso a alimentos saudáveis de famílias em um Bairro da periferia urbana do Município de Sobral através de hortas comunitárias, orgânicas e sustentáveis como estratégia de promover Educação Alimentar e Nutricional. Métodos e Materiais: Estudo descritivo com características de intervenção comunitária sob a abordagem qualitativa. A amostra inclui 15 pessoas de famílias beneficiárias do Programa Bolsa Família, acompanhadas pelo Centro de Saúde da Família. Foram realizados quatro encontros educativos sobre alimentação saudável com enfoque na inclusão de frutas, legumes e verduras. Além, do manejo de hortas para o cultivo do próprio alimento. Resultados: Os encontros tiveram duração de 8 horas ao dia, totalizando 24 horas. O momento foi oportuno para treinamento ofertado por um técnico em olericultura orgânica pela entidade parceira, que transmitiu os conhecimentos de maneira prática, em que os participantes aprenderam a preparar a terra, a semear, plantar, regar, colher. No decorrer do treinamento a nutricionista pesquisadora, transmitiu informações nutricionais. Os encontros aconteceram em dias seguidos, nos turnos manhã e tarde. Conclusão: Diante do que foi vivenciado, a pesquisa se mostrou útil para melhoria do grau de conhecimento das participantes, promoveu reflexão crítica sobre a segurança alimentar e nutricional. Ressaltou a importância de se cultivar o próprio alimento para torná-lo acessível.

This study aims at contributing to the improvement of access to healthy food for families in a neighborhood of the urban outskirts of the Municipality of Sobral through community organic and sustainable vegetable gardens as a strategy to promote Food and Nutrition Education. It is a descriptive study with characteristics of community intervention using a qualitative approach. The sample includes 15 people from families benefited from the Family Grant Program (Bolsa Família), accompanied by the Family Health Center. Four educational meetings were held on healthy eating with a focus on the inclusion of fruits and vegetables. In addition, the participants were also taught how to manage vegetable gardens for the cultivation of the food itself. The meetings lasted 8 hours a day, totaling 24 hours. The moment was ideal to provide training offered by an organic olericulture technician provided by the partner entity, who shared the knowledge in a practical way, where the participants could learn how to prepare the earth, to sow, to plant, to water, and to harvest. During the training, the nutritionist researcher also shared nutritional information. The encounters took place on consecutive days, during the morning and afternoon shifts. In view of what was experienced, the research proved to be useful for improving the participants' knowledge on the topic, promoting a critical reflection on food and nutritional security. It also emphasized the importance of cultivating the food itself to make it accessible.

Contribution of the carbonized rice husk added to the substrate in the production of vegetable seedlings

The carbonized rice husk (CRH) is an agro-industrial residue with great potential for use in mixtures with other substrates for the production of vegetable seedlings. Thus, the purpose of this study was to evaluate the effect of the addition of CRH to the commercial substrate for the production of greenhouse seedlings. The evaluated vegetables were lettuce, broccoli and mustard, cultivated in polystyrene foam (Styrofoam®) trays. Five treatments were evaluated: 100% of the commercial substrate (CS); 25% of CRH + 75% of CS; 50% of CRH + 50% of CS; 75% CRH + 25% CS; and 100% CRH, in a completely randomized design with twelve replicates. The substrates were evaluated for their physical and chemical characteristics. The morphometric evaluations were: number of leaves per plant, plant height, shoot fresh matter yield, root length, and shoot and root dry matter yield. The data were submitted to regression analysis, and the homogeneity of the variance between the experiments was confirmed by the Cochran test. With the addition of CRH to the substrate, there was an increase in total porosity and P content and a reduction in density, water holding capacity, cation exchange capacity, electrical conductivity, and N, K, S, Ca and Mg contents. The carbonized rice husk added to the commercial substrate is a viable alternative for the production of lettuce, broccoli and mustard seedlings. The quality of the vegetable seedlings was higher when there was a 25% CRH + 75% CS mixture.

Preliminary assessment of weed population in vegetable and fruit farms of Taif, Saudi Arabia / Avaliação preliminar da população de plantas daninhas em fazendas de hortaliças e frutas de Taif, Arábia Saudita

A significant level of yield losses in the vegetable and fruit farms are attributed to the weed populations of the area. This study was conducted for eighteen months during 2019-2020 to assess the presence of various weed families, related species, and their densities in the vegetable (CROP A) and fruit (CROP B) farms of Taif, Saudi Arabia. During the study, fourteen and ten weed families were noted in the vegetable and fruit farms of the studied area, respectively. Poaceae family weeds (729) were significantly higher in numbers followed by the families Asteraceae (414), Chenopodiaceae (338), and Gisekiaceae (153). In the vegetable farms, two weed species of the family Poaceae including Setaria viridis (437) and Eleusine indica ssp (277) were present in the higher numbers followed by Chenopodium murale (166) of the Chenopodiaceae family. In the fruit farms, the weed species Cynodon dactylon of the family Poaceae represented the highest weed density (172) followed by Gisekia pharnaceoides L. species (153) of family Gisekiaceae and Portulaca oleracea (59) belonging to the family Portulacaceae. The vegetable and fruit farms of the Taif region face severe weed pressure that affects the cultivated crops. This study depicts a comprehensive picture of weed diversity and density in the vegetable and fruit farms of the area. The results of this study will be beneficial in developing effective weed management practices for better crop production.

Um nível significativo de perdas de rendimento nas fazendas de hortaliças e frutas é atribuído às populações de ervas daninhas da área. Este estudo foi conduzido por dezoito meses durante 2019-2020 para avaliar a presença de várias famílias de ervas daninhas, espécies relacionadas e suas densidades nas fazendas de vegetais (CROP A) e frutas (CROP B) de Taif, Arábia Saudita. Durante o estudo, catorze e dez famílias de plantas daninhas foram observadas nas fazendas de hortaliças e frutas da área estudada, respectivamente. As plantas daninhas da família Poaceae (729) foram significativamente maiores em número, seguidas pelas famílias Asteraceae (414), Chenopodiaceae (338) e Gisekiaceae (153). Nas hortas, duas espécies de plantas daninhas da família Poaceae, incluindo Setaria viridis (437) e Eleusine indica ssp (277), estavam presentes em maior número, seguidas por Chenopodium murale (166) da família Chenopodiaceae. Nas fruticulturas, a espécie de plantas daninhas Cynodon dactylon da família Poaceae representou a maior densidade de plantas daninhas (172) seguida das espécies Gisekia pharnaceoides L. (153) da família Gisekiaceae e Portulaca oleracea (59) pertencentes à família Portulacaceae. As fazendas de hortaliças e frutas da região de Taif enfrentam uma forte pressão de ervas daninhas que afeta as culturas cultivadas. Este estudo apresenta um quadro abrangente da diversidade e densidade de plantas daninhas nas fazendas de hortaliças e frutas da região. Os resultados deste estudo serão benéficos no desenvolvimento de práticas eficazes de manejo de plantas daninhas para uma melhor produção das culturas.

Transgenic merA and merB expression reduces mercury contamination in vegetables and grains grown in mercury-contaminated soil.

KEY MESSAGE: Arabidopsis, tobacco, tomato and rice with merA/merB expressed reduced mercury concentration of leaves, fruits or grains. These mercury-breathing plants produce agricultural products with acceptable levels of mercury from contaminated soil. Mercury contamination in plant food products can cause serious health risks to consumers. Transgenic approaches to enhance mercury phytoremediation have been accomplished with expression of bacterial merA and merB genes to convert toxic organic mercury to less toxic elemental mercury. However, little is known whether these genes can be used to produce safe foods from plants grown on mercury-contaminated land. We have used Arabidopsis and tobacco as model plants for leafy vegetables, and tomato and rice as representative fruit and grain crops to investigate whether merA and merB expression allows for production of safe foods from mercury-contaminated soils. Our results show that grown on heavily contaminated land with mercury, merA and merB expressing transgenic plants can produce vegetables, fruits and grains safe for human and animal consumption, while the wild-type plants cannot. The merA and merB transgenic plants can also efficiently remove mercury from soil. With increasing mercury contamination problems for the agricultural land worldwide, the use of the merA and merB genes can help produce safe food from mercury-polluted land and also remediate contaminated soils.

Effects of LED spectra on growth, gas exchange, antioxidant activity and nutritional quality of vegetable species.

This research aimed to investigate the effects of three LED spectra on growth, gas exchange, antioxidant activity and nutritional quality of three vegetable species. The compressible vegetable facilities (CVF) were developed and three kinds of typical LED lights (spectra) were set, including white LED light (W), red-blue-green LED light (RBG), and red-blue-white LED light (RBW). Three vegetable species, i.e. lettuce (Lactuca sativa L. cv. Rome), cherry radish (Raphanus sativas L. cv. Hongxin) and cherry tomato (Lycopersicon esculentum M. cv. Mosite), were chosen and grown (matrix culture) in the three LED lights for 40, 40 and 100 days, respectively. The results indicated that the vegetable plants grew well and were compact in the RBG and RBW treatments. There was the highest biomass or fruit (tomato) in the RBG treatment and the least one in the W treatment for three vegetable species. There were no significant differences in harvest index, ratio of shoot to root, and water content among three treatments. The production efficiency values of 9.0-9.7, 9.9-13.5 and 11.8-12.5 g DW d-1 m-2 for lettuce, radish and tomato plants in the RBG and the RBW treatments were higher than those in the W treatment. The photosynthetic and transpiration rates of three vegetable species in the RBG treatment were the highest among three treatments and the W treatment had the least one. There were significant effects of three spectra on antioxidant activities of three vegetable species. Higher PPFD percentages of blue in the RBG light and the RBW light increased the antioxidant activities of all vegetable plants compared the W light. But it had no significant difference between the RBG light and the RBW. The organic components including soluble sugar (SS) and protein (Prt) of lettuce and radish plants were affected significantly by three spectra, but not for tomato plants. The contents of Mg and Zn of radish plants in the RBG treatment were higher than those in other treatments. There were significant positive effects of RBW treatment on the contents of N and Mg of tomato plants. The different spectra did not affect the contents of N-NO3 and Cu of vegetable plants. This study demonstrated that the RBG light (spectrum) significantly enhanced the growth, gas exchange, antioxidant activity of the lettuce, radish, and tomato cultivars used in this study, and there are significant effects of different LED spectra on the nutritional quality (including organic components and several mineral elements) of the different species.

Composition and quality traits of vegetables grown in a low-tech aquaponic system at different fish stocking densities.

BACKGROUND: Aquaponics is considered a sustainable system for the production of fish and vegetables. However, little is known about the effects of different system variables on vegetable quality. Hence, the aims of this study were to evaluate the influence of aquaponics on the composition and quality traits of three vegetable species in relation to stocking density of the common carp (Cyprinus carpio L.), in comparison with those of plants grown in hydroponics. RESULTS: The highest cumulative vegetable marketable yield was obtained in low-density aquaponics (APL), followed by hydroponics (HP) and high-density aquaponics (APH). Vegetable quality traits showed species-specific responses. In general, phosphorus concentration was higher in plants grown in APH and lower in those grown in HP, while the opposite was observed for nitrate concentration. In lettuce (Lactuca sativa L.), sugar content was the highest in APH, whereas for Swiss chard (Beta vulgaris L. subsp. vulgaris Cicla group), the aquaponics treatments increased only glucose content. No differences in sugar content were observed in Catalogna (Cichorium intybus L. Catalogna group). The lowest and highest phenolic acid concentrations in the aboveground biomass of Catalogna and lettuce were observed in HP and APH treatments, respectively. For Swiss chard, APH treatment resulted in the highest caffeic acid content, whereas ferulic acid was the highest in HP. CONCLUSIONS: Aquaponics at low stocking density increased plant yield, compared to HP, without compromising vegetable quality, whereas aquaponics at high stocking density improved vegetable quality, but at the expense of yield. © 2020 Society of Chemical Industry.

Lymphocytes exposed to vegetables grown in waters contaminated by anticancer drugs: metabolome alterations and genotoxic risks for human health.

Wastewater irrigation of crops may be effective to avoid depletion (about 70%) of freshwater resources. However, the use of reclaimed waters containing persistent microcontaminants such as antineoplastic drugs is of high environmental concern. These active compounds may affect human health with potentially severe adverse effects. To better understand the impact on human health following irrigation of crops with reused contaminated waters, we exposed four edible plants, Brassica rapa, Lactuca sativa, Raphanus sativus, and Triticum durum, to two commonly used antitumoral drugs: 5-fluorouracil (5-FU), and Cisplatin (CDDP), using metabolomics as a potential functional genomics tool to combine with genotoxicity experiments. The metabolome of the treated and untreated plants was analysed to detect biochemical alterations associated to the exposure, and the potential genotoxic damage related to human exposure to the treated plants was evaluated using the comet assay in human lymphocytes, which are characterized by high sensitivity to genotoxic substances. The edible species were able to assimilate 5-FU and CDDP during the treatment, affecting the biochemical pathways of these plants with subsequent metabolome modifications. These metabolic alterations differed according to the specific species used for the test. Furthermore, all vegetables treated with two concentrations of the selected drugs (10 and 100 µg/L) caused significant (p < 0.0001) genotoxic damage in the cells of the immune system at a higher level than in the lymphocytes directly exposed to single antineoplastic drugs.

Immobilization of heavy metals in vegetable-growing soils using nano zero-valent iron modified attapulgite clay.

Nowadays, the problem of heavy metal pollution in vegetables is received wide attention. In this work, attapulgite clay (ATTP), as a cheap and readily available inorganic mineral material, was modified with nano zero-valent iron (nFe0@ATTP) for heavy metal immobilization in soil. Batch experiments were employed to evaluate the optimal remediation performance by ATTP before and after modified with nFe0 through planting Pakchoi (Brassica chinesis L.) in Cd, Cr, and Pb contaminated soil from Changsha. The results showed that amendments can all increase the pH value of soils, and notably decrease the concentration of extractable Cd, Cr, and Pb in soil. The germination rate and root length of Pakchoi were promoted, and the activities of peroxidase (POD), catalase (CAT), and malondialdehyde (MDA) contents were notably reduced besides superoxide dismutase (SOD) activity after treatments with ATTP and nFe0@ATTP. Vicia faba-micronucleus test indicated that the application of amendments reduced the toxicity of heavy metals on the genetic material of Vicia faba root tip cells. The nFe0@ATTP were found to well convert Cd, Cr, and Pb into less bioavailable state in soil, thus blocking heavy metal uptake by plants. This material could be a promising amendment for heavy metals contaminated soil.

Health Risk Assessment of Potentially Toxic Trace and Elements in Vegetables Grown Under the Impact of Kajaran Mining Complex.

Mining industry is one of the priority sectors of Armenia's economy. However, mining complexes without treatment facilities, such as those in Armenia, have adverse environmental impact. Moreover, soil contamination can pose a potential risk to human health, particularly, through the consumption of food crops. In this study, 12 soil and 32 vegetable composite samples were collected from the city of Kajaran where Armenia's biggest copper and molybdenum mine is located. The concentrations of Cu, Mo, Cd, Hg, As, and Pb were analyzed using atomic absorption spectrophotometer. Diet study was conducted using food frequency questionnaire. Non-carcinogenic and carcinogenic risks to human health through vegetable consumption were assessed. The results indicated that different vegetables have different trace element uptakes. Also, the transfer factors (TFs) for each vegetable varied across elements. TFs were less than 1 for the majority of trace elements. Nevertheless, in some samples of studied vegetables, the concentrations of Hg, Cd, and Pb exceeded the maximum allowable levels. THQ of Mo exceeded 1 for all the studied vegetables, while THQ of Cu exceeded 1 for potato and bean, indicating a potential health risk posed by chronic exposure. Exceedingly high levels of Mo exposure can be related to high incidence of anemia among Armenians, since Mo interacts with Cu and is a potential cause of copper deficiency-induced anemia. With regard to cancer risk, none of the carcinogenic risk values exceeded the threshold level.

Composting of municipal solid waste by different methods improved the growth of vegetables and reduced the health risks of cadmium and lead.

Reutilization of putrescible municipal solid wastes (MSW) in agriculture can provide valuable plant nutrients. However, it may pose serious noncarcinogenic health risks for a human when contaminants, especially the heavy metals in MSW, end up in plants through the waste-soil-plant continuum. This study examined the effects of composting methods viz. aerobically (AC), anaerobically (ANC), and aerobic-anaerobically (AANC) composted MSW material on (i) fertilizer value: vegetable yield, nitrogen (N) mineralization, and apparent N recovery (ANR); and (ii) associated health risks: selected heavy metal concentration, daily intake of metals (DIM), health risk index (HRI), hazard index (HI), and target hazard quotient (THQ) when applied to a loamy soil. All the aforementioned compost materials were incorporated into the sandy loam soil filled in pots and carrot and spinach were cultivated for 85 and 90 days, respectively. After soil application, between 51 and 56% of the applied organic N was mineralized from ANC material, while the values in case of AC and AANC were 26-31% and 34-40%, respectively. Consequently, dry matter yield and vegetable N uptake from composts were in the order ANC > AANC > AC (P < 0.05). Further, vegetable ANR was the highest from ANC (56 and 56%) than AANC (42 and 45%), and AC (30 and 33%) for spinach and carrot, respectively (P < 0.05). Interestingly, plant uptake of lead and cadmium was lowest from ANC as compared to AC or AANC (P < 0.05), irrespective of the vegetable type. Consequently, DIM, HRI, and THQ for these metals were substantially lower in the former as compared to the latter compost materials. Further, HI from ANC material was 50% lower over the unfertilized control indicating the absence of noncarcinogenic human health risks via vegetable intake. This all indicates that from viewpoint of sustainable waste recycling in agriculture, anaerobic composting is superior to the other composting methods.

Differences in the uptake and bioconcentration of dichlorodiphenyltrichloroethane by eight vegetable cultivars and their health risk assessments.

Dichlorodiphenyltrichloroethane (DDT) is not easily degraded in soils, which will pose a threat to human health. We investigated the differences of eight vegetables' capacity to take up DDT, removing DDT from soil, and tolerating DDT (monitoring the responses of growth, root morphology and photosynthesis of vegetables to DDT). These vegetables included Chinese mustard (two genotypes, B.jf and B,jm), napa cabbage (two genotypes, B.coz and B.coc) and Bok choy (four genotypes, B.cz, B.cq, B.cs and B.chg). The results demonstrated that 5 mg kg-1 DDT did not display significant effects on the growth of most vegetables in this study. As compared to the control, 5 mg kg-1 DDT significantly increased the shoot and root biomass, the fine root numbers, and the fine root ratio for the genotype of B.chg. However, 5 mg kg-1 DDT exposure showed a negative effect on the shoot growth of two genotypes of napa cabbage. In general, 5 mg kg-1 DDT did not significantly affect the photosynthesis and root morphology of most vegetables in this study. Consuming these vegetables had a low non-cancer health risk, but showed a high cancer health risk. In addition, among the eight vegetables, B.chg accumulated less DDT in the edible parts and had low values of HRnon-cancer and HRcancer for consuming these vegetables containing DDT. Planting these vegetables might promote the degradation of DDT reducing its residual amount in soil.

Salinity stress enhances color parameters, bioactive leaf pigments, vitamins, polyphenols, flavonoids and antioxidant activity in selected Amaranthus leafy vegetables.

BACKGROUND: Amaranthus tricolor is a unique source of betalain (ß-cyanin and ß-xanthin) and a source of natural antioxidants, such as leaf pigments, vitamins, polyphenols and flavonoids in leafy vegetables. It has substantial importance for the food industry, since these compounds detoxify reactive oxygen species in humans and are involved in defense against several diseases. In addition, previous research has shown that salt stress elevates these compounds in many leafy vegetables. Therefore, we evaluated the effect of salinity stress on these compounds. RESULTS: Three selected A. tricolor genotypes were studied under three salinity levels to evaluate the response of these compounds. Genotype, salinity stress and their interactions significantly affected all the traits studied. A significant and remarkable increase in L, a*, b*, chroma, ß-cyanin, ß-xanthin, betalain, total carotenoids, ß-carotene, ascorbic acid, total polyphenolic content, total flavonoid content and total antioxidant capacity were observed under 50 and 100 mmol L-1 NaCl concentrations. Bioactive leaf pigments, ß-carotene, vitamin C, phenolics and flavonoids showed good antioxidant activity due to positive and significant interrelationships with total antioxidant capacity. CONCLUSIONS: Amaranthus tricolor can tolerate salinity stress without compromising the high quality of the final product. Therefore, it could be a promising alternative crop in saline-prone areas around the globe. © 2018 Society of Chemical Industry.

Productivity and Antioxidant Activity of Wild, Reconstituted, and Hybrid Strains of the Pink Oyster Mushroom, Pleurotus djamor (Agaricomycetes), from Mexico.

The genus Pleurotus is the third most commonly produced edible fungi in the world. In addition, species of genus Pleurotus have functional properties such as anticancer, antiviral, antimicrobial, anti-inflammatory, and antioxidant activities, which are mainly attributed to phenolic compounds. For these reasons, this study evaluated the productivity and antioxidant activity (AA) of 2 wild strains (white and pink), 2 reconstituted strains (called "BB" and "RR"), and 4 hybrid strains (H1, H2, H3, and H4) of P. djamor from monokaryotic components (neohaplonts). The results showed that the white wild-type strain and the reconstituted strains exhibited the best production potential, expressed as biological efficiency and mycelial growth rate. The carpophores of hybrid strains H1 and H3 had the greatest AA, as evaluated with DPPH radical scavenging and reducing power assays, respectively. The H3 strain had the highest total phenol (TP) content. Pearson correlations led us to conclude that the mycelial growth rate has a regular inverse correlation with TP and a regular direct correlation with AA of methanolic extracts from carpophores and myce-lia. This is, to our knowledge, the first report in the literature about the effect of Pleurotus strain hybridization through a chemical de-dikaryotization process on TP content.

Metal contents and potential health risk assessment of crops grown in a former mining district (Romania).

The Cd, Cu, Pb and Zn contents in home-grown crops in a former mining district were determined in order to evaluate the non-carcinogenic long-term potential health risk related to crop consumption. The potential health risk was investigated by estimating the daily intake and the hazard quotients. For all crop categories, the daily intake and the target hazard quotient were below the threshold values for Cd, Cu, and Zn. The daily intake of Pb exceeded the oral reference dose, while the target hazard quotient for vegetables was above 1, indicating a potential health risk. The total target hazard quotient for the individual metals decreased in the following order: Pb>Cd>Cu>Zn. This study confirmed that the daily consumption of crops grown in contaminated soils could pose health risks to humans.

Effects of cadmium and copper mixtures to carrot and pakchoi under greenhouse cultivation condition.

A pot experiment was undertaken to investigate the effects of Cd and Cu mixtures to growth and nutrients (sugar, carotene or vitamin C) of carrot and pakchoi under greenhouse cultivation condition. The study included: (a) physical-chemical properties of soil and soil animals in response to Cd and Cu stress; (b) bioaccumulation of heavy metals, length, biomass, contents of sugar and carotene (vitamin C) of carrot and pakchoi; (c) estimation the effects of Cd and Cu mixtures by multivariate regression analysis. The results implied that heavy metals impacted negative influence on soil animals' abundance. The metals contents in plants increased obviously with Cd and Cu contamination in soil. The biomass production and nutrients declined with Cd and Cu contents increasing. Cd (20 mg kg-1) treatment caused maximum reduction of sugar content (45.29%) in carrot root; maximum reduction in carotene content (75.73%) in carrot, 75.1% sugar content reduction and 70.58% vitamin C content reduction in pakchoi shoots were observed with addition of Cd (20 mg kg-1) and Cu (400 mg kg-1) mixture. The results of multivariate regression analysis indicated that combination of Cd and Cu exerts negative effects to both carrot and pakchoi, and both growth and nutrients were negatively correlated with metals concentrations. It is concluded that the Cd and Cu mixtures caused toxic damage to vegetable plants as Cd and Cu gradient concentrations increased.

Responses of bacterial community to dibutyl phthalate pollution in a soil-vegetable ecosystem.

Phthalate esters (PAEs) are a type of plasticizer that has aroused great concern due to their mutagenic, teratogenic, and carcinogenic effects, wherefore dibutyl phthalate (DBP) and other PAEs have been listed as priority pollutants. In this study, the impacts of DBP on a soil-vegetable ecosystem were investigated. The results showed that DBP could accumulate within vegetable tissues, and the accumulative effect was enhanced with higher levels of DBP contamination in soils. DBP accumulation also decreased vegetable quality in various ways, including decreased soluble protein content and increased nitrate content. The diversity of bacteria in soils gradually decreased with increasing DBP concentration, while no clear association with endophytic bacteria was observed. Also, the relative abundance, structure, and composition of soil bacterial communities underwent successional change during the DBP degradation period. The variation of bulk soil bacterial community was significantly associated with DBP concentration, while changes in the rhizosphere soil bacteria community were significantly associated with the properties of both soil and vegetables. The results indicated that DBP pollution could increase the health risk from vegetables and alter the biodiversity of indigenous bacteria in soil-vegetable ecosystems, which might further alter ecosystem functions in agricultural fields.

Estimating CO2 gas exchange in mixed age vegetable plant communities grown on soil-like substrates for life support systems.

If soil-like substrate (SLS) is to be used in human life support systems with a high degree of mass closure, the rate of its gas exchange as a compartment for mineralization of plant biomass should be understood. The purpose of this study was to compare variations in CO2 gas exchange of vegetable plant communities grown on the soil-like substrate using a number of plant age groups, which determined the so-called conveyor interval. Two experimental plant communities were grown as plant conveyors with different conveyor intervals. The first plant community consisted of conveyors with intervals of 7 days for carrot and beet and 14 days for chufa sedge. The conveyor intervals in the second plant community were 14 days for carrot and beet and 28 days for chufa sedge. This study showed that increasing the number of age groups in the conveyor and, thus, increasing the frequency of adding plant waste to the SLS, decreased the range of variations in CO2 concentration in the "plant-soil-like substrate" system. However, the resultant CO2 gas exchange was shifted towards CO2 release to the atmosphere of the plant community with short conveyor intervals. The duration of the conveyor interval did not significantly affect productivity and mineral composition of plants grown on the SLS.

Impact of storm runoff on Salmonella and Escherichia coli prevalence in irrigation ponds of fresh produce farms in southern Georgia.

AIMS: To examine Salmonella and Escherichia coli in storm runoff and irrigation ponds used by fresh produce growers, and compare Salmonella serovars with those found in cases of human salmonellosis. METHODS AND RESULTS: We collected water before and after rain events at two irrigation ponds on farms in southern Georgia, USA, and collected storm runoff/storm flow within the contributing watershed of each pond. Salmonella and E. coli concentrations were higher in ponds after rain events by an average of 0·46 (P < 0·01) and 0·61 (P < 0·05) log10 most probable number (MPN) per 100 ml respectively. Salmonella concentrations in storm runoff from fields and forests were not significantly higher than in ponds before rain events, but concentrations in storm flow from streams and ditches were higher by an average of 1·22 log10 MPN per 100 ml (P < 0·001). Eighteen Salmonella serovars were identified from 155 serotyped isolates, and eight serovars were shared between storm runoff/storm flow and ponds. Seven of the serovars, including five of the shared serovars, were present in cases of human illness in the study region in the same year. However, several serovars most commonly associated with human illness in the study region (e.g. Javiana, Enteritidis, and Montevideo) were not found in any water samples. CONCLUSIONS: Salmonella and E. coli concentrations in irrigation ponds were higher, on average, after rain events, but concentrations of Salmonella were low, and the ponds met FDA water quality standards based on E. coli. Some similarities and notable differences were found between Salmonella serovars in water samples and in cases of human illness. SIGNIFICANCE AND IMPACT OF THE STUDY: This study directly examined storm runoff/storm flow into irrigation ponds and quantified increases in Salmonella and E. coli following rain events, with potential implications for irrigation pond management as well as human health.

From lesser-known to super vegetables: the growing profile of African traditional leafy vegetables in promoting food security and wellness.

There are hundreds of traditional leafy vegetables and wild food plants of horticultural and nutritional significance in Africa. These lesser-known crops and wild food plants that are highly adapted to harsh growing conditions thrive with little care and are available when other sources of food fail or are out of season. They are rich in micronutrients and are often the cheapest sources of many essential vitamins and minerals in many localities. Many of them are very important functional foods in African traditional diets and are rich in nutraceuticals, including polyphenols, tannins, flavonoids and flavonols, that exert demonstrable antioxidant, free radical scavenging and enzyme inhibition activities and have antimicrobial properties that provide scientific justification and possible mechanisms for their use in the management of a wide range of ailments, including diet-related, non-communicable diseases such as diabetes, hypertension and cardiovascular diseases. African traditional leafy vegetables are invaluable in promoting food security and wellness in Africa on account of their availability and affordability, their great nutritional value, chemotherapeutic and health-promoting properties and other unique qualities. Long recognised by the rural populace as quality food items, they are becoming more popular even with the more affluent urban elites. There is the need to develop improved management practices for these super vegetables to promote their cultivation and boost their exploitation for food security and wellness in Africa. © 2018 Society of Chemical Industry.

Levels of some heavy metals in vegetables from artisanal mining sites of Dilimi River, Bukuru and Barkin Ladi North Central Nigeria: any public health concern?

Background: North Central Nigeria is the food basket of Nigeria but is also known for its artisanal mining with attendant public health consequences which is hitherto unquantified. Vegetables grown close to these mining sites may be contaminated with heavy metals. Objective: This study has estimated health risk associated with heavy metals HM (Cd, Cr, Cu, Zn, Se and Ni) in vegetables harvested inform the mining areas of Dilimi, Bukuru and Barkin Ladi by calculating the Daily intake, Target Hazard Quotient (THQ), Hazard Index (HI) and the Cancer risk (CR) for adults and children in the local population. Material and methods: Vegetable, soil, irrigation water and sediments samples were collected, digested, ashed and analyzed for HM using an Atomic Absorption Spectrometer (AAS). Results: The concentration of heavy metals in vegetables were in the order Cd < Se < Cr < Cu < Ni < Zn. There were higher HM levels in soil than vegetables samples. The daily intake of HM from vegetable consumption decreased in the following order Cd < Se < Cr < Cu < Ni < Zn. At least 62.5% of vegetable samples had THQ values > 1 in Dilimi, Bukuru and Barkin ladi (Adults) while 13% of vegetable samples had THQ values > 1 in children. The THQ of nickel ranged from 0.38-2.73 and 0.21-1.53 in adults and children respectively. The bio-concentration factor ranged from 0.026-7.52, 0.01-0.36 and 0.0011-1.23 in Dilimi, Bukuru and Barkin Ladi respectively for all the studied heavy metals. The cancer risk values ranged from 0.011-0.04 and 0.00066-0.02 across all the studied areas for adults and children respectively. HI values for adults were all >1 and also the total cancer risk was above the acceptable range of 10-4. Conclusion: Since THQ is > 1 in most of the samples, HI values > 1 for adults in all the vegetable and cancer risk above the acceptable limit consumption of vegetables from the study areas is not free of risk.