scholarly journals Potential of different crop species for nickel and cadmium phytoremediation in peri-urban areas of Varanasi district (India) with more than twenty years of wastewater irrigation history

2013 ◽  
Vol 8 (1) ◽  
pp. 8 ◽  
Author(s):  
Sumita Pal ◽  
Harikesh Bahadur Singh ◽  
Amitava Rakshit
Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2737 ◽  
Author(s):  
Barkat Rabbi ◽  
Zhong-Hua Chen ◽  
Subbu Sethuvenkatraman

The projected increase of the world’s population, coupled with the shrinking area of arable land required to meet future food demands, is building pressure on Earth’s finite agricultural resources. As an alternative to conventional farming methods, crops can be grown in protected environments, such as traditional greenhouses or the more modern plant factories. These are usually more productive and use resources more efficiently than conventional farming and are now receiving much attention—especially in urban and peri-urban areas. Traditionally, protected cropping has been predominantly practised in temperate climates, but interest is rapidly rising in hot, arid areas and humid, tropical regions. However, maintaining suitable climatic conditions inside protected cropping structures in warm climates—where warm is defined as equivalent to climatic conditions that require cooling—is challenging and requires different approaches from those used in temperate conditions. In this paper, we review the benefits of protected cropping in warm climates, as well as the technologies available for maintaining a controlled growing environment in these regions. In addition to providing a summary of active cooling methods, this study summarises photovoltaic (PV)-based shading methods used for passive cooling of greenhouses. Additionally, we also summarise the current humidity-control techniques used in the protected cropping industry and identify future research opportunities in this area. The review includes a list of optimum growing conditions for a range of crop species suited to protected cropping in warm climates.


2021 ◽  
Vol 5 (2) ◽  
pp. 34-45
Author(s):  
N. Abdullahi ◽  
E. C Igwe ◽  
M. A. Dandago ◽  
N. B. Umar

The qualities of agricultural soil and water are diminishing continuously due to the rigorous anthropogenic activities currently stocking the soil with a lot of toxic chemicals including heavy metals. Heavy metals are highly persistent and non-biodegradable, control of their contamination is very tricky to handle. Their presence in soil and water is detrimental to food crops and humans. Various sources of heavy metals contaminants and the role of urban food production on human heavy metal contamination were discussed.Heavy metals have their way into the soil and food crops through wastewater irrigation and production in contaminated soil. The habitual heavy metals contamination sources for food crops are wastewater irrigation, abuse of agrochemicals, production in the contaminated field, atmospheric deposit when foods are exposed to contaminated air, and unethical mining activities. Agricultural soil in urban and peri-urban areas are heavily contaminated with heavy metal due to various anthropogenic activities. Wastewater irrigation intensify the contamination by supplying the soil with more heavy metals. The heavy metals are passed to food during production and subsequently to humans after consumption.


2017 ◽  
Vol 17 (5) ◽  
pp. 1479-1489 ◽  
Author(s):  
Shiyang Yin ◽  
Xiaomin Gu ◽  
Yong Xiao ◽  
Wenyong Wu ◽  
Xingyao Pan ◽  
...  

Although wastewater reuse in agriculture can ease water scarcity, this practice also alters the variation of groundwater recharge and groundwater levels. This study employed a geostatistical method to systematically investigate the spatio-temporal variations and storage fluctuations of groundwater in a wastewater irrigation area in a southeastern suburb of Beijing. Specifically, we generated an optimal geostatistical model for measuring groundwater levels. Furthermore, we proposed that universal kriging is a suitable method for examining groundwater spatial variations, whereas a raster-based model can provide high accuracy for studying groundwater fluctuations; the nugget effect value of groundwater levels increases with increasing exploitation intensity. Our results indicated that groundwater levels increased overall in the early stages of wastewater irrigation development, followed by local increases in some pockets in the middle stages of development, large-scale increases in the late stages and an increasing variation of magnitude over time. The results also showed that groundwater level declined less on farmlands than that in urban areas, suggesting that wastewater irrigation facilitates groundwater conservation by reducing groundwater exploitation and enhancing groundwater recharge. Our results are conducive to developing an effective groundwater management plan and for improving the accuracy of groundwater resource assessments.


1996 ◽  
Vol 22 (3) ◽  
pp. 167-174
Author(s):  
J A Cantrill ◽  
B Johannesson ◽  
M Nicholson ◽  
P R Noyce

2001 ◽  
Vol 60 (2) ◽  
pp. 99-107 ◽  
Author(s):  
Holger Schmid

Cannabis use does not show homogeneous patterns in a country. In particular, urbanization appears to influence prevalence rates, with higher rates in urban areas. A hierarchical linear model (HLM) was employed to analyze these structural influences on individuals in Switzerland. Data for this analysis were taken from the Switzerland survey of Health Behavior in School-Aged Children (HBSC) Study, the most recent survey to assess drug use in a nationally representative sample of 3473 15-year-olds. A total of 1487 male and 1620 female students indicated their cannabis use and their attributions of drug use to friends. As second level variables we included address density in the 26 Swiss Cantons as an indicator of urbanization and officially recorded offences of cannabis use in the Cantons as an indicator of repressive policy. Attribution of drug use to friends is highly correlated with cannabis use. The correlation is even more pronounced in urban Cantons. However, no association between recorded offences and cannabis use was found. The results suggest that structural variables influence individuals. Living in an urban area effects the attribution of drug use to friends. On the other hand repressive policy does not affect individual use.


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