Rapa Chinensis Research Articles

Utilizing sludge from catfish farming to produce vermicompost for improving soil quality

Abstract Earthworm organic waste is processed into vermicompost, which is of varying quality depending on the substrate. In vermicomposting, earthworms can promote nitrogen mineralization and effect nitrification. A challenging-to-absorb nutrient will be converted into a nutrient that plants can easily absorb to improve nutrients in soil and increase crop production. In this study, an experimental model of organic fertilizer production from catfish pond bottom sludge was implemented. Sludge from the bottom of catfish ponds is composted with water hyacinth in aquatic ponds to produce organic fertilizer, mature fertilizer is used as a substrate for vermicomposting. The impact of vermicompost on plant growth parameters was evaluated through its use to improve nutrients in soil. Sludge, compost, vermicompost, and soil quality were also evaluated for their physical and chemical properties. Results show that the growth coefficient of earthworms is 129.3±1.15% per 30 days, and the average amount of organic fertilizer created is 126±3.51 kg per 30 days. The quality parameters of vermicompost all meet national standards for organic fertilizer quality. The moisture and total organic matter content in mature fertilizer are 31% and 21.9%, respectively. The content of nutrients N and P increased compared to input materials, the corresponding values reached 2.84% and 0.96%. The C/N ratio is 7.7, microbiological and heavy metal indicators are within the accepted limits. In the experiment using vermicompost to cultivate Brassica rapa chinensis, the yield growth rate was the highest. After 21 days of planting, the growth rate is fast and the height reaches 25.0±0.38 cm. The biochemical composition ensures safety according to food regulations for leafy vegetables. Vermicomposting is recommended as a sustainable and suitable technique for catfish pond sludge utilizing.

Utilizing recycled pumice and oyster shell waste for cost-effective treatment to mitigate pollutants and toxicity in swine wastewater

Despite the abundant nutrients that could be reutilized in swine wastewater, inadequate wastewater management leads to excessive metals and organic matter, causing environmental impacts on aquatic and terrestrial ecosystems. In this study, we recycled waste pumice and oyster shells for the cost-effective treatment and reclamation of swine wastewater. The toxicity of the treated wastewater was assessed using the soil nematode Caenorhabditis elegans and Chinese cabbage Brassica rapa chinensis. Our findings showed significant removal of suspended solids, biochemical oxygen demand, chemical oxygen demand, total phosphorus, and heavy metals (As, Cu, Ni, and Zn) from the swine wastewater after treatment with pumice and oyster shells. Moreover, untreated wastewater significantly inhibited the germination of Chinese cabbage, a trend that was reversed in treated wastewater. Both treated and untreated swine wastewater stimulated the growth of Chinese cabbage. Additionally, untreated swine wastewater exhibited high toxicity to the growth and reproduction of C. elegans after 72 hours of exposure, whereas treated wastewater showed notably reduced toxicity. The recycled pumice and oyster shells significantly induced growth and showed no toxicity in Chinese cabbage. These results suggest that pumice and oyster shell waste can effectively reduce environmental toxicity in raw swine wastewater, offering a cost-effective wastewater treatment solution for small-scale pig farms.

The Formulation and Characterization of Antimicrobial Packaging from Chitosan and Curry Leaf (Murraya Koenigii) Essential Oil for Vegetables Packaging

This study formulated chitosan-based antimicrobial films incorporating curry leaf (Murraya koenigii) essential oil using the film casting method. The films were characterized with 0%, 1%, and 2% concentrations of essential oil, and evaluated through physical, mechanical, and biological tests. Physical and mechanical tests included tensile testing, film thickness, pH, and water solubility. The film thickness ranged from 0.04 mm to 0.08 mm, and pH values ranged from 3.84 to 4.93. Water solubility was 22.7%, 20.56%, and 40.17% for films with 0%, 1%, and 2% essential oil, respectively. Tensile strength was assessed alongside antimicrobial properties using the zone of inhibition method against E. coli and Bacillus cereus. The films showed significant inhibition zones for the gram-negative E. coli and minimal inhibition for the gram-positive B. cereus. Shelf-life tests on dwarf pak choi (Brassica rapa chinensis) and baby kailan (Brassica oleracea L.) demonstrated an extended shelf-life of up to 14 days using common storage methods such as on-top placement and wrapping. This study concludes that chitosan-based films infused with curry leaf essential oil exhibit promising antimicrobial properties, making them a viable food packaging material with considerable strength, elongation, and flexibility, effectively inhibiting foodborne pathogens.

The Effect of Mol of Rice Water Waste and Kepok Banana Peel to The Growth of Brassica rapa chinensis

MOL merupakan larutan fermentasi oleh mikroba dan bersumber dari bahan organik seperti kulit pisang. MOL berguna dalam mendorong penguraian bahan organik dan dapat digunakan sebagai pupuk organik cair karena mengandung NPK. Penelitian ini bertujuan untuk pengaruh fermentasi campuran air cucian beras putih dan kulit pisang kepok terhadap pertumbuhan tanaman pakcoy (Brassica rapa chinensis) dan untuk mengetahui konsentrasi terbaik MOL dari kulit pisang kepok yang diberikan. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) dengan 5 perlakuan dan 5 ulangan. Perlakuan pada penelitian ini adalah P0 (kontrol), P1 (10%), P2 (20%), P3 (30%), dan P4 (40%). Data dianalisis menggunakan analisis varians (ANOVA) yang dilanjutkan dengan Uji Duncan pada taraf signifikansi 5%. Hasil penelitian menunjukkan bahwa MOL kulit pisang kepok berpengaruh terhadap pertumbuhan tanaman pakcoy pada beberapa parameter yaitu berat basah, berat kering dan panjang akar tanaman namun tidak terhadap tinggi dan jumlah daun tanaman pakcoy. Perlakuan P2 (20%) menunjukkan hasil terbaik.

Enhancing the carbon content of coal gangue for composting through sludge amendment: A feasibility study

Cocomposting coal gangue and sludge eliminates the challenge of utilizing coal gangue. However, there is limited understanding about the feasibility of cocomposting sludge and coal gangue, as well as the composting indicators, functional microorganisms, and safety risks involved. Therefore, this study evaluated the feasibility of enhancing carbon composting in coal gangue by incorporating sludge along with sawdust as a conditioner. Three laboratory-scale reactors were designed and labeled as T1 (20 % coal gangue, 60 % sludge, and 20 % sawdust), T2 (40 % coal gangue, 40 % sludge, and 20 % sawdust), and T3 (60 % coal gangue, 20 % sludge, and 20 % sawdust). Seed germination and plant growth assessments were conducted to ensure compost stability and assess phytotoxicity to cabbage (Brassica rapa chinensis L.) in terms of growth and biomass. The results indicated that the temperature, pH, EC and ammonia nitrogen of all three reactor conditions met the requirements for product decomposition. Composting was successfully achieved when the sludge proportion was 20 % (T3). However, when the sludge proportion was markedly high (T1), the harmlessness of the compost was reduced. The germination indices of T1, T2, and T3 reached 95 %, 122 %, and 119 % at maturity, respectively. This confirmed that the harmless cycle, which involved promoting condensation and aromatization, enhancing decay, and reducing composting time, was shorter in T2 and T3 than in T1. Coal gangue can also serve as a beneficial habitat for microorganisms, promoting an increase in their population and activity. Potting experiments in sandy soil revealed that the mechanism of action of compost products in soil included not only the enhancement of soil nutrients but also the improvement of soil texture. The results of this study suggest that using coal gangue as a raw material for composting is an efficient and environmentally friendly approach for producing organic fertilizers.

Application of Micro-Nanobubble Aeration in Spinach (Amaranthus viridis) and Pakchoi (Brassica rapa Chinensis) Cultivation with the Wick System

This study aimed to determine the effect of micro-nanobubble generator (MNBG) aeration on the cultivation of spinach (Amaranthus viridis) and pakchoi (Brassica rapa chinensis) hydroponic wicks. The basic principle of this system is that the axis capillary action flows nutrients to the planting medium. There are no moving parts so the nutrients can settle rapidly and the dissolved oxygen content is limited. Micro-nanobubbles (MNB) have the characteristics of a long residence time in the water so that their generation can operate intermittenttly. This study aims to determine the effect of applying (MNBG) with a flow rate of 0.98 L/minute on root length, plant height, and wet weight of spinach and pakchoi plants in wick hydroponics. Cultivation was hold on a free environment. There are three kinds of treatment; without aeration (N0), aeration 15 minutes x 4 for 24 hours (N15), and aeration 30 minutes x 4 for 24 hours (N30). Variations in the types of materials used in this study were spinach and pakchoi, as per treatment was repeat five samples. The study used a Randomized Block Design (RBD). The measurement results compared by the One-Way ANOVA test (5% level), then continued with Duncan's test to determine the difference. The results showed that there was an effect of applying intermittentt MNBG aeration on the average weight and height of the spinach plants, N15 treatment was more effective than the N0 and N30. Intermittentt MNBG aeration did not show a significant difference in the average weight of pakchoi. Keywords: Aeration, Hydroponics, Spinach, Pakchoi, wick

Optimized core-shell lanthanide nanoparticles with ultrabright Ce3+-modulated second near-infrared emission for "lighting" plants.

Second near-infrared (NIR-II, 1000-1700 nm) photon-mediated fluorescence imaging has attracted extensive interest in the field of bioimaging. However, NIR-II fluorescent nanoprobes competent for plant imaging have been rarely developed. Herein, lanthanide-doped nanoparticle (LDNP) optimal core-shell structure and ultrabright NIR-II emission were developed for "lighting" plants. The Ce3+-doped active shell coated on the NaErF4:Tm core enables dual-mode red upconversion (UC) and NIR-II downconversion (DC) emission of LDNPs upon 980 nm laser excitation. Under the optimized doping content, the intensities of red UC and NIR-II DC emission were respectively boosted by 5- and 19-fold those of the core nanoparticles, which endowed LDNPs with ideal NIR-II emissive capabilities for optical imaging of plants. Significantly, the NIR-II fluorescent signal affords much higher signal-to-noise rate than the red UC. LDNPs were modified with polyethyleneimine to enable outstanding hydrophilicty and facilitate their uptake by plants. Arabidopsis thaliana and Nicotiana benthamiana were chosen as plant models for NIR-II imaging studies. The toxic effect of LDNPs after being transported into Brassica rapa chinensis was systematically studied on mice. The NIR-II imaging strategy offers a promising method for studying the uptake and transport of nanoparticles in plants.

Phosphorus recovery from high solid content liquid fraction of digestate using seawater bittern as the magnesium source

Phosphorus recovery from digestate is considered a challenge because the possible discharge can lead to eutrophication. This study focuses on phosphorus recovery as struvite from the liquid fraction of swine manure digestate at a high total solids concentration, by using a lab-scale crystallizer operated in continuous mode (7 L·d−1). A by-product of salt production (seawater bittern, SWB) was assessed as Mg source for the formation of struvite instead of a chemical dosage (MgCl2) within a circular economy approach. Different Mg/P (1.8:1; 2:1; 3:1) ratios and different TS contents (TS 3.5 and 4.5 %) were studied. The maximum P recovery of 85 % and N recovery of 52 % was obtained at 4.5 % of TS and Mg/P ratio of 2:1, corresponding to an overall P and N recovery on the raw digestate of 70 % and 46 %, respectively. The presence of struvite was confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM-EDS). Dried samples were then used as fertilizer in agronomic pot tests using Brassica rapa chinensis. Struvite obtained, showed comparable fertilizing properties in comparison with conventional fertilizers in terms of P (Mineral 5.6 ± 0.4; Poultry 5.7 ± 0.2; Struvite 5.9 ± 0.1 g kg−1), N and total biomass content such as chlorophylls ratio. The growth tests confirmed the possible use of struvite recovered as competitive alternative to conventional chemical phosphate fertilizers. The results showed that it can be possible to promote sustainable P recovery from high solids digestates by the combination of crystallizer reactor and Mg-salt byproducts.

Trace Elements Uptake in Brassica rapa chinensis Cultivated in Ultrabasic (Oxisol) and Ultisol Soils, North Borneo

The study aims to investigate the soil physico-chemical properties and trace elements uptake of Brassica rapa chinensis plants cultivated in ultrabasic (oxisol) and ultisoil soil of Ranau, North Borneo, Malaysia by inductively coupled plasma-optical emission spectrometry (ICP-OES). This study can contribute to propose a more sustainable soil management practice. All selected trace elements bioavailability in ultrabasic soil was significantly higher than ultisols except for Ca and Cd. There was no significant amount of difference in soil pH (slightly acidic) and electrical conductivity (slightly saline) between these soil types. However, a significant amount of difference between the percentage of soil moisture and organic matter between ultrabasic and ultisol soils was observed. These might contribute to the uptake of elements into the studied plant. The B. rapa chinensis is a hyperaccumulator of Cd and Pb for both type of soils. The B. rapa chinensis is an accumulator of As when grown in ultrabasic soil, while an accumulator of Co when grown in ultisol soil. Although Pb was not detected in ultisol soil as compared to ultrabasic soil, the concentration of Pb in plants cultivated in ultisol soil had exceeded the maximum permissible limit of Malaysia Food Regulation 1985. Soil amendment in frequently use agriculture sites needs to be conducted such as the addition of organic matter to reduce transfers of trace elements from soil to plants that can pose toxicity risk.

EFFECT OF DOLOMITE AND CHICKEN MANURE APPLICATION ON PAK CHOI (Brassica rapa chinensis) PRODUCTION AND CARBON DIOXIDE EMISSIONS IN TROPICAL PEATLANDS

The current study was aimed to determine the effect of ameliorant on Pak choi (Brassica rapa chinensis) productivity, CO2 emissions, and factors affecting the rate of CO2 emission. The study was carried out using a non-factorial completely randomized design with seven treatments. The imposed treatment are without ameliorant (control), 10, 20, 30 ton ha-1 chicken manure, 4 ton ha-1 Dolomite + Chicken Manure @ 10 ton ha-1, Dolomite 4 ton ha-1 + Chicken Manure @ 20 ton ha-1 and Dolomite 4 ton ha-1 + Chicken Manure @ 30 ton ha-1. The variables observed are the chemical properties of peat soil, fresh and dry weight of pak choi, CO2 emissions, and factors that affect CO2 emissions. The results of the study revealed that the combination of Dolomite and chicken manure has a significant effect on the studied parameters and the combination of 4 ton ha-1 dolomite + 30 ton ha-1 chicken manure had the highest pH change (average of 6.36), highest productivity, and CO2 emission (344.42 mg cm-2hr-1). Results of the study can be concluded that Dolomite and chicken manure has a significant effect on the various growth parameters of B. rapa chinensis and the properties of the peat soil.

Portable Raman leaf-clip sensor for rapid detection of plant stress

Precision agriculture requires new technologies for rapid diagnosis of plant stresses, such as nutrient deficiency and drought, before the onset of visible symptoms and subsequent yield loss. Here, we demonstrate a portable Raman probe that clips around a leaf for rapid, in vivo spectral analysis of plant metabolites including carotenoids and nitrates. We use the leaf-clip Raman sensor for early diagnosis of nitrogen deficiency of the model plant Arabidopsis thaliana as well as two important vegetable crops, Pak Choi (Brassica rapa chinensis) and Choy Sum (Brassica rapa var. parachinensis). In vivo measurements using the portable leaf-clip Raman sensor under full-light growth conditions were consistent with those obtained with a benchtop Raman spectrometer measurements on leaf-sections under laboratory conditions. The portable leaf-clip Raman sensor offers farmers and plant scientists a new precision agriculture tool for early diagnosis and real-time monitoring of plant stresses in field conditions.

Effects of chemical fertilizer and organic inputs on the population of Eisenia foetida and plant growth parameters of Brassica rapa chinensis

Agricultural farming is a main economic activity in Guyana and agricultural products are produced on a daily basis to provide food security for our growing population. As a result, chemical fertilizers are used extensively in agriculture farming for faster crop yields as opposed to the use of organic fertilizers which promotes healthy fruits, vegetables and a safer environment for soil organisms. This study investigated the effects of chemical fertilizer and organic inputs (cattle dung and grass clipping) on the population of Eisenia foetida and plant growth parameters of Brassica rapa chinensis. The findings revealed that E. foetida were negatively affected by the chemical fertilizer but the organic fertilizer showed positive effects over the study period 2016-2017. The application of chemical fertilizers (urea) and organic inputs (cattle dung and grass clipping) to the various treatments were done in parts based on the recommended dosage which was calculated to be a total of 750 grams for both cattle dung and grass clipping per pot for the organic treatment, a total of 7.5 grams per pot for the chemical treatment and no additives were applied to the soil in the control treatment. A total of 360 adult E. foetida were used for analytical purposes and 20 E. foetida were introduced per pot after a single B. rapa chinensis was planted.

Development of the cabbage webworm, Hellula undalis (Fabricius) (Lepidoptera : Pyralidae) on different brassica cultivars in Central Vietnam

The cabbage webworm, Hellula undalis (Fabricius) (Lepidoptera: Pyralidae) is a serious insect-pest on brassicas and other crucifers. Previous study has indicated that biology of H. undalis depends on host plant. The development time and survival rate of immature stages, longevity and fecundity of the cabbage webworm were investigated on three cultivars of brassica such as Indian mustard (Brassica juncea), leaf mustard (Brassica integrifolia) and pak choi (Brassica rapa chinensis). Developmental time from first instar larva to adult and life cycle of the webworm reared with pak choi were longer than those with leaf mustard and India mustard. Longevity and fecundity of the adults on pak choi were lower than those on leaf mustard and India mustard. The results indictated that pak choi was the less suitable host plant followed by leaf mustard and Indian mustard. Thus, the development of resistance plant cultivars should be intended as an integrated pest management measure in the control of H. undalis.

The role of chemical amendments on modulating ammonia loss and quality parameters of co-composts from waste cocoa pods

PurposeNitrogen loss as ammonia (NH3) in a waste cocoa pod co-composting process was determined following the addition of three potentialchemical amendments that could lower NH3 loss. Further, amended compost products were assessed for quality and possible phytotoxicity in a pot experiment.MethodsPod borer damaged cocoa pods were co-composted in lab-scale vessels under ambient conditions with double superphosphate, phosphoric acid, and gypsum at 2%, 5% and 1% of fresh weight, respectively. NH3 emitted during composting was trapped in standard H2SO4 and determined titrimetrically. Composting mixtures were sampled on days 0, 7, 56 and 90 to monitor pH, total C, total N, and C:N ratio. Mature co-composts were incorporated to the soil at 20 t ha−1 and growth response of Chinese cabbage plants (Brassica rapa chinensis) assessed for the phytotoxicity.ResultsThe chemical amendments were ineffective (p > 0.05) in preventing loss of NH3 but the quality of composting mixtures were significantly (p < 0.0001) improved. The manure compost generated had acceptable parameters (C, 31.2–31.9% and C:N ratio, 9–10:1) and were free from phytotoxicity for soil application as revealed by the response of Chinese cabbage crop.ConclusionsChemical amendments used in the co-composting process mainly modulated pH without any detrimental effects on quality. The results also demonstrated that the NH3 loss is insignificant from the cocoa waste-composting process. Further studies are required with increased rates of acidifying amendments like phosphoric acid to further augment the quality of cocoa pod composts.

Vegetables cultivated with exposure to pure and naturally occurring β-N-methylamino-L-alanine (BMAA) via irrigation

Bioaccumulation and biomagnification of β-N-methylamino-L-alanine (BMAA), a potent neurotoxin, has been demonstrated in various food webs. It is alarming as this intensification of BMAA will result in exposure to higher concentrations from a direct cyanobacterial source. As more food items are being identified as a source of BMAA and with the large variations in BMAA content, the aim of the present study was to evaluate BMAA uptake by, and accumulation in, two commonly consumed vegetables, Lactuca sativa and Allium fistulosum. Plants exposed to pure BMAA in controlled laboratory experiments, as well as vegetables naturally irrigated with water containing a BMAA producing cyanobacterial bloom were evaluated during growth and ripening. In the laboratory exposures, free BMAA was detected in both the edible ripe parts of L. sativa and A. fistulosum after 60 days of exposure to a total of 4.5 µg BMAA. However, in the bloom exposure samples no BMAA could be detected in the ripe vegetables of A. fistulosum, Cucurbita pepo, or Brassica rapa chinensis. The study emphasises the need to further screen items for BMAA to understand the human exposure risk as well as the difference between BMAA uptake patterns with free BMAA and that contained in cyanobacterial cells.

Water quality remediation using aquaponics sub-systems as biological and mechanical filters in aquaculture

This paper presents data obtained through trials on small-scale aquaponics sub-system which performs the roles of biological and mechanical filters for aquaculture water quality remediation. Aquaponics is a bio-integrated food production system, consisting of closed recirculating aquaculture combined with hydroponics. The trials were conducted on Nile tilapia (Oreochromis niloticus), and green beans (Phaseolus vulgaris) and the Chinese cabbage (Brassica rapa chinensis) over a period of 70 days. The results revealed that the system is more efficient in terms of plant growth and does not adversely affect the growth of captive stock of fish. Mean (± S.D.) values of water temperature, DO, pH, NH3-N, NO2-N, NO3-N and PO4-P during the trial were 25.2 ± 0.25 °C, 6.6 ± 0.13 mg/L, 7.14 ± 0.06, 0.23 ± 0.02 mg/L, 0.39 ± 0.22 mg/L, 0.89 ± 0.37 mg/L and 0.45 ± 0.04 mg/L, respectively. The average total weight gain by O. niloticus was 637.2 ± 8.49 g, and feed conversion ratio (FCR) was 1.47 ± 0.01 which indicated the efficiency of Nile tilapia in converting feed mass – a universally standard measure of efficiency of feed assimilation into weight gain, especially when there is no additional source of nourishment. High survival rate (95 ± 2.8%) was noticed during the trials. The average (±SD) values of biomass gain by P. vulgaris and B. rapa were 951.6 ± 1.6 g and 85.3 ± 13.4 g, respectively. The system was cost-effective and efficient in purging the toxic waste from water, resulting in remediation of water quality for the recirculating aquaculture system. This reflected the effectiveness of biofiltration which is currently assessed by its ability to completely remove the ammonia and minimize the generation of nitrite.

Feasibility of medical stone amendment for sewage sludge co-composting and production of nutrient-rich compost

The feasibility of medical stone (MS) amendment as an innovative additive for dewatered fresh sewage sludge (DFSS) co-composting was assessed using a 130-L vessel-scale composter. To verify successful composting, five treatments were designed with four different dosages (2, 4, 6, and 10) % of MS with a 1:1 mixture (dry weight) of DFSS + wheat straw (WS). The WS was used as a bulking agent. A control without any amendment treatment was carried out for the purpose of comparison. For DFSS co-composting, the amendment with MS improved the mineralization efficiency and compost quality in terms of CO2 emissions, dehydrogenase enzyme (DE), electrical conductivity (EC), water-solubility, and total nutrients transformation. The DTPA-extractable Cu and Zn were also estimated to confirm the immobilization ability of the applied MS. Seed germination and plant growth tests were conducted to ensure the compost stability and phytotoxicity for Chinese cabbage (Brassica rapa chinensis L.) growth and biomass, as well as chlorophyll content. The results showed that during the bio-oxidative phase, DOC, DON, AP, NH4+-N, and NO3−-N increased drastically in all the MS-blended treatments, except the application of 2% MS and the control treatment; significantly lower water-soluble nutrients were observed in the 2% MS and control treatments. A novel additive with 6–10% MS dosages considerably enhanced the organic matter conversion in the stable end-product (compost) and reduced the maturity period by two weeks compared to the 2% MS and control treatments. Consequently, the maturity parameters (e.g., EC, SGI, NH4+-N, DOC, and DON) confirmed that compost with 6–10% MS became more stable and mature within four weeks of DFSS co-composting. At the end of composting, significantly higher DTPA-extractable Cu and Zn contents were observed in the control treatment, and subsequently, in the very low application (10%) of MS. Higher MS dosage lowered the pH and EC to within the permissible limit compared to the control, while increased concentrations of water-soluble nutrients diminished the DTPA-extractable Cu and Zn contents. In addition, plant growth experiments demonstrated that the addition of compost with 150 kg ha−1 TKN improved the Chinese cabbage biomass and chlorophyll level. The highest dry weight biomass (2.78 ± 0.02 g/pot) was obtained with 6% MS-blended compost while the maximum chlorophyll content was found with application of 4% MS compost (41.84 SPAD-unit) for Chinese cabbage. Therefore, 6–10% MS can be recommended to improve DFSS composting and to reduce the period to maturity by two weeks when considering its composting effect on Chinese cabbage growth, biomass yield, and chlorophyll level. However, amendment with 6% MS is a more economically feasible approach for DFSS co-composting.

Assessment of veterinary drugs in plants using pharmacokinetic approaches: The absorption, distribution and elimination of tetracycline and sulfamethoxazole in ephemeral vegetables.

The present study was carried out to demonstrate novel use of pharmacokinetic approaches to characterize drug behaviors/movements in the vegetables with implications to food safety. The absorption, distribution, metabolism and most importantly, the elimination of tetracycline (TC) and sulfamethoxazole (SMX) in edible plants Brassica rapa chinensis and Ipomoea aquatica grown hydroponically were demonstrated and studied using non-compartmental pharmacokinetic analysis. The results revealed drug-dependent and vegetable-dependent pharmacokinetic differences and indicated that ephemeral vegetables could have high capacity accumulating antibiotics (up to 160 μg g-1 for TC and 38 μg g-1 for SMX) within hours. TC concentration in the root (Cmax) could reach 11 times higher than that in the cultivation fluid and 3–28 times higher than the petioles/stems. Based on the volume of distribution (Vss), SMX was 3–6 times more extensively distributed than TC. Both antibiotics showed evident, albeit slow elimination phase with elimination half-lives ranging from 22 to 88 hours. For the first time drug elimination through the roots of a plant was demonstrated, and by viewing the root as a central compartment and continuous infusion without a loading dose as drug administration mode, it is possible to pharmacokinetically monitor the movement of antibiotics and their fate in the vegetables with more detailed information not previously available. Phyto-pharmacokinetic could be a new area worth developing new models for the assessment of veterinary drugs in edible plants.

Heterogeneity of zeolite combined with biochar properties as a function of sewage sludge composting and production of nutrient-rich compost

In the present study, biochar combined with a higher dosage of zeolite (Z) and biochar (B) alone were applied as additives for dewatered fresh sewage sludge (DFSS) composting using 130-L working volume lab-scale reactors. We first observed that the addition of a mixture of B and Z to DFSS equivalent to 12%B+10% (Z-1), 15% (Z-2) and 30% (Z-3) zeolite (dry weight basis) worked synergistically as an amendment and increased the composting efficiency compared with a treatment of 12%B alone amended and a control without any amendment. In a composting reactor, the addition of B+Z may serve as a novel approach for improving DFSS composting and the quality of the end product in terms of the temperature, water-holding capacity, CO2 emissions, electrical conductivity, water-soluble and total macro-nutrient content and phytotoxicity. The results indicated that during the thermophilic phase, dissolved organic carbon, NH4+-N and NO3−-N increased drastically in all biochar amended treatments, whereas considerably low water-soluble nutrients were observed in the control treatment throughout and at the end of the composting. Furthermore, the maturity parameters and dissolved organic carbon (DOC) indicated that compost with 12%B+15%Z became more mature and humified within 35days of DFSS composting, with the maturity parameters, such as CO2 evolution and the concentration of NH4+-N in the compost, being within the permissible limits of organic farming in contrast to the control. Furthermore, at the end of composting, the addition of higher dosage of biochar (12%) alone and 12% B+Z lowered the pH by 7.15 to 7.86 and the electrical conductivity by 2.65 to 2.95mScm−1 as compared to the control, while increased the concentrations of water-soluble nutrients (gkg−1) including available phosphorus, sodium and potassium. In addition, greenhouse experiments demonstrated that the treatment of 150kgha−1 biochar combined with zeolite and that of 12%B alone improved the yield of Chinese cabbage (Brassica rapa chinensis L.). The highest dry weight biomass (1.41±0.12g/pot) was obtained with 12%B+15%Z amended compost. Therefore, 12%B+15%Z can be potentially applied as an amendment to improve DFSS composting.

Heavy metals in sludge during anaerobic sanitary landfill: Speciation transformation and phytotoxicity

Sanitary landfill persists as a predominant sludge disposal method in particular in China. In this study, successive subsurface sludge samples (0.3 m deep) were collected from a bioreactor landfill unit where an anaerobic process took place during a 500 d period. The sludge samples were analyzed for total concentrations of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) and their species distributions, together with selected sludge chemical properties. In addition, the sludge samples were subjected to phytotoxicity testing. The results showed that the mobilities of Cd and Ni were decreased with landfill time, while the mobilities of Cr, Cu, Pb and Zn remained consistently low over the landfill period. The residual amounts of all these heavy metals were increased with landfill time, suggesting that the anaerobic sanitary landfill is an effective sludge stabilization method to reduce the ecological risk of these heavy metals. The increase in the sludge pH value with landfill time tended to promote the precipitation of heavy metals. Moreover, the sludge stabilization was found to be indicated by the formation of humic substance (HS) and volatilization of volatile matter (VM). The germination index (GI) values of barley (Hordeum vulgare L.) and Chinese cabbage (Brassica rapa chinensis) seeds grown in the 500 d anaerobically stabilized sludge were approximately 5.2- and 4.1-times higher than the values of those grown in the fresh sludge. The final sludge extract did not cause any significant inhibitory effect on the germination of the two types of seeds.