Evaluation of the Characteristics of Pollutant Discharge in Tomato Hydroponic Wastewater (HWW) for Sustainable Water Management in Korea

In South Korea, the use of hydroponic cultivation has been on the rise. However, this system produces a large amount of wastewater. In this study, the amount of wastewater generated by hydroponic tomato cultivation is identified, and a management plan is proposed. Based on the analysis of 103 tomato HWW samples, it was found that the electrical conductivity (EC) was 4.25 ± 1.01 dS/m, the nitrogen (N) content was 411.21 ± 122.64 mg/L, and the phosphorus (P) content was 47.74 mg/L, which caused eutrophication. Therefore, agricultural reuse and HWW treatment were proposed. Regarding the annual HWW load, 1 ha of hydroponics discharges 964.26 kg/ha of N, 111.95 of P, 937.46 of K, 795.14 of Ca, 313.83 of Mg, and 405.40 of S. The trace elements were heavy metals, which were calculated as Fe—4.03, Mn—0.77, Zn—1.08, B—2.25, Cu—0.38, and Mo—0.05 kg/ha. Since wastewater is a national source of drinking water, it needs to be collected and treated. Inter-item correlation analysis showed that most of the fertilizer components were correlated with the EC concentrations. This study can be used to determine the concentrations required for agricultural reuse and to determine the treatment capacity in HWW management

Contamination and Spatial Distribution of Metal(loid)s in the Stream Sediment near the Greenhouse

As greenhouse horticulture continues to increase in South Korea, the effects of metal(loid)s from wastewater discharges on stream sediments were analyzed. A total of 106 samples were analyzed for cadmium (Cd), boron (B), copper (Cu), nickel (Ni), lead (Pb), zinc (Zn), chromium (Cr), manganese (Mn), and iron (Fe). The coefficient of variation (CV) of the metal(loid)s components was 96.58% for Mn, 93.40 for Zn, 62.47 for B, 58.90 for Pb, and 58.14 for Cd, suggesting anthropogenic sources. Correlation analysis suggested a cumulative source for Cd-Zn and B, and cluster analysis suggested an anthropogenic source for Cu, Pb, B, and Mn. The contamination factor (CF) suggested the need to trace the source of contamination to Pb (3.21 ± 1.89) and B (1.33 ± 0.83) and EF to Pb (3.30 ± 1.81) and B (1.44 ± 0.94). The analytical results identify anthropogenic sources of Pb, B, and Cd. The high contamination of Cd suggests the influence of mining areas, and Pb suggests the influence of traffic, fertilizers, pesticides, and fossil fuels in greenhouses, in addition to the influence of mines. B confirmed the impact of the facility’s vegetable wastewater and suggested the need to further examine the cumulative impact of Mn, Fe, etc. By utilizing the facility horticulture wastewater for ecological restoration and other agricultural uses, we aim to prevent stream sediment pollution and realize a sustainable agricultural environment

Evaluation and Improvement Measures of the Runoff Coefficient of Urban Parks for Sustainable Water Balance

As the impermeable sidewalk area increases in urban areas, diverse problems related to water occur. The purposes of this research were to increase the rainwater infiltration rate through water balance analysis and estimate the runoff coefficient according to land cover types in urban parks. The regression equations and runoff coefficients relative to the rainwater infiltration rate were estimated according to the land cover types and applied to eight urban parks. In the results of the experiment, the runoff coefficient was 0.245 for vegetation areas, 0.583 for permeable sidewalks, 0.963 for sidewalk blocks, and 1.000 for impervious sidewalks, which had 100% outflow. The results show that the vegetation area in urban parks is significantly related to rainfall–runoff, infiltration, and evapotranspiration. The average of eight urban parks was 126.52 mm, indicating that 11.80% of the rainfall was recharged into groundwater. Additionally, the average runoff rate was 498.56 mm, indicating that 46.52% was leaked externally. Therefore, it is suggested to decrease the impermeable sidewalk areas in urban parks. Additionally, extending the waterway, swamp, and gravel sidewalk areas is suggested. Urban parks should be developed in order to contribute to hydrological control through the water balance in urban land use

Growth, Physicochemical, Nutritional, and Postharvest Qualities of Leaf Lettuce (<i>Lactuca sativa</i> L.) as Affected by Cultivar and Amount of Applied Nutrient Solution

The effects of different nutrient solution quantities on growth, physicochemical, nutritional, and postharvest qualities of lettuce were investigated. Two differently pigmented Korean leaf lettuce cultivars “Geockchima” and “Cheongchima” were grown in soilless perlite culture supplied with 250, 500, 1000, and 2000 mL·d−1·plant−1 nutrient solutions. Several growth parameters (plant height, leaf number, fresh weight, dry matter) were evaluated. The highest lettuce growth was observed when plants were supplied with 1000 mL·d−1·plant−1. Cultivating lettuces in the lowest nutrient solution quantity showed higher dry matter, crude fiber, osmolality, chlorophyll, and anthocyanin contents. Upon increasing the nutrient solution, the crispiness, greenness, and levels of ascorbic acid, nitrogen, and potassium, increased, while phosphorus and magnesium were unaffected, and calcium content declined. Postharvest qualities were better maintained in lettuces irrigated with the least amount of nutrient solution, extending their shelf life. We conclude that lettuce can be grown with 1000 mL·d−1·plant−1 for higher yield, and short-term storage and/or transportation. However, when lettuces need to be stored for a certain period, such as long-distance shipment, they should be cultivated with a limited nutrient solution, which requires further detailed investigation. The results of this study can be applied for distributing, storing, transporting, and marketing lettuce

Correction: Son et al. Variation in Pathogenic Organisms as Affected by Using Hydroponic Nutrient Wastewater in Horticultural Facilities. <i>Agriculture</i> 2022, <i>12</i>, 1340

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Traditional Medicine Analysis and Sustainable Use of Korean Pond Wetland Plants in the Agricultural Landscape

This study surveyed the most commonly observed plants at 40 pond wetlands in rural villages in Korea and assessed their use patterns in traditional medicine (TM) with reference to the contents of the Korea Traditional Knowledge Portal (KTKP). In this survey, 457 taxa in 108 families were identified. For these, there are use patterns in TM for 314 taxa; overall, 68.8% of the surveyed plants have uses in TM. The 314 taxa that have applications in TM involve 596 types of disease treatment and 771 types of efficacy. On average, for each taxon, there are 4.0 types of efficacy and 6.6 types of disease treatment. TM from 210 taxa have been described as applied to organs in 10 regions of the body: liver 123, lung 82, spleen 57, stomach 57, heart 45, large intestine 43, kidney 40, bladder 23, small intestine 16, and gall bladder 8. The results of this study will help support the conservation of pond wetlands that provide national biodiversity and various ecosystem services, by increasing the recognized value of pond wetlands even when they are no longer used in farming. Thus, this study can support educational materials for eco-experience and can be applied in the conservation of Korean pond wetlands

Variation in Pathogenic Organisms as Affected by Using Hydroponic Nutrient Wastewater in Horticultural Facilities

Among the horticulture facilities in Korea, the hydroponic cultivation method has been increasingly used. This study aimed to identify fungi and bacterial species in hydroponic cultivation and highlight the need for sterilization to recycle the discharged drainage. Samples were collected from a number of paprika, tomato, and strawberry hydroponic greenhouses. Vinyl and glass greenhouses were studied, and the drainage discharge was of two types: direct discharge and collection after discharge. In total, 24 fungal and six bacterial species were detected from 399 and 151 densities, respectively. The primary fungal and bacterial species identified were from the genera Fusarium, Pythium, and Phytophthora as well as Agrobacterium and Pseudomonas. Statistical analysis revealed that the species number and density of fungi and bacteria were higher in strawberry than in tomato or paprika. These values were higher for vinyl greenhouses than for glass greenhouses. This study on the reuse of drainage from hydroponic greenhouses may contribute to the recycling of resources and reduction in water pollutant emission; this will thus help us to implement sustainable horticulture practices

Effect of farmland type on the transport and spatial distribution of metal(loid)s in agricultural lands near an abandoned gold mine site: Confirmation of previous observations

In many parts of the world, metal(loid)s resulting from mining activities are causing significant environmental concern, in particular because they are contaminating agricultural lands. In this respect, a previous study in South Korea suggested that a specific agricultural practice, associated with the growing of rice in paddy fields, could contribute specifically to the geographic spread of metal(loid)s contamination away from mine sites. The purpose of the research described in this article was to confirm this hypothesis at a different site. Samples from the surface soil of agricultural lands were collected from 374 sites (267 paddy soils and 107 dry field soils). The concentrations of As, Pb, Cd, Cu and Zn from the samples were analyzed and descriptive statistics and multivariate statistical analysis were carried out to identify potential sources of these various elements. In addition, geographical information systems (GIS) technology was applied to analyze the interrelationship between the mining activities and the distribution of meta(loid)s in agricultural lands. The results clearly show that the transport and distribution of As and Pb originating from the abandoned mine are distinct depending on the agricultural practice that was adopted locally. The highest concentrations of As and Pb are in agricultural soils nearest the abandoned mine site (< 1 km) because of climatic factors such as wind and precipitation that affect the direct mobilization of metal-bearing mine wastes. However, the distribution characteristics of As and Pb in the oxidizing environment of dry field soils in general suggest that the degree of pollution by these elements fell notably as the distance from the abandoned mine increased. In the alternatingly oxidizing and reducing environment of paddy soils, by contrast, the distribution of As and Pb is noticeably different from those of the dry field soils. Arsenic in particular is widely distributed across the study area with a high level of pollution regardless of the distance from the abandoned mine. These results confirm the hypothesis that the transport characteristics of metal(loid)s initially mobilized from an abandoned mine site into the paddy soils are predominantly governed by the specific submerged environment of rice paddy soils and these specific environments impact a wider area than climatic factors

Analysis of metal(loid)s contamination and their continuous input in soils around a zinc smelter: Development of methodology and a case study in South Korea

Soil contamination due to atmospheric deposition of metals originating from smelters is a global environmental problem. A common problem associated with this contamination is the discrimination between anthropic and natural contributions to soil metal concentrations: In this context, we investigated the characteristics of soil contamination in the surrounding area of a world class smelter. We attempted to combine several approaches in order to identify sources of metals in soils and to examine contamination characteristics, such as pollution level, range, and spatial distribution. Soil samples were collected at 100 sites during a field survey and total concentrations of As, Cd, Cr, Cu, Fe, Hg, Ni, Pb, and Zn were analyzed. We conducted a multivariate statistical analysis, and also examined the spatial distribution by 1) identifying the horizontal variation of metals according to particular wind directions and distance from the smelter and 2) drawing a distribution map by means of a GIS tool. As, Cd, Cu, Hg, Pb, and Zn in the soil were found to originate from smelter emissions, and As also originated from other sources such as abandoned mines and waste landfill. Among anthropogenic metals, the horizontal distribution of Cd, Hg, Pb, and Zn according to the downwind direction and distance from the smelter showed a typical feature of atmospheric deposition (regression model: y = y0 + αe−βx). Lithogenic Fe was used as an indicator, and it revealed the continuous input and accumulation of these four elements in the surrounding soils. Our approach was effective in clearly identifying the sources of metals and analyzing their contamination characteristics. We believe this study will provide useful information to future studies on soil pollution by metals around smelters