Figure 1. No Cu, Mn or Zn was detected in water from the reservoirs and artesian well studied. These results are similar to those reported by Sobral et al.
Cd levels in the water samples varied from 0. Cd is highly toxic and can cause poisoning when ingested in water or food McGrath et al. Field evaluation of Cd and Zn phytoextraction potential by the hyperaccumulators Thlaspi caerulescens and Arabidopsis halleri.
Environmental Pollution,v. The element is carcinogenic and can occur in agriculture through the use of pesticides and fertilizers Sharma et al.
Heavy metal contamination of soil and vegetables in suburban areas of Varanasi, India. Ecotoxicology and Environmental Safety, v. Cd contamination in the water samples may be due to excessive use of phosphate fertilizers Nacke et al. Availability of heavy metals Cd, Pb and Cr in agriculture from commercial fertilizers. Archives of Environmental Contamination and Toxicology, v.
Heavy metal contamination in brazilian agricultural soils due to application of fertilizers. Environmental risk assessment of soil contamination.
Rijeka: Intech Open, Field accumulation risks of heavy metals in soil and vegetable crop irrigated with sewage water in western region of Saudi Arabia. Saudi Journal of Biological Sciences, v. Bizarro et al. These values are relatively low; however, intensive farming using agrochemicals fertilizers and pesticides can increase heavy metal concentrations in the soil-water-plant system, especially in the case of elements poorly retained by the soil and easily lost to leaching Singh and Agrawal, SINGH, R.
Potential benefits and risks of land application of sewage sludge. Waste Management, v. There were no changes in Cd content as a function of varying monthly rainfall, and only a slight increase in some of the reservoirs after periods of intense rainfall, possibly due to large amounts of sediment carried by erosion or more intense percolation of the element in the soil.
Ni levels in the water samples ranged from 1. This may also partially explain the decline in Ni in the cultivated areas, given its greater movement in the soil, which may favor leaching, leading to Ni contamination of the groundwater and, consequently, dammed water, exacerbated by evaporation.
The rise in Ni levels after intense rainfall January and June may indicate the introduction of the metal along with sediment carried by erosion. Figure 2. Figure 3. Pb content varied between 0. Ramalho et al. The values recorded in our study were higher than the established standard of 0. This reservoir supplies farming area AC5, which displayed the highest soil heavy metal levels, possibly due to the use of agrochemicals and the irrigation water itself Vieira, VIEIRA, L.
Figure 4. As such, given its low mobility in the soil, it is suggested that this metal is transported primarily by erosion and concentrates in the reservoir water; since this water is used for irrigation, the element returns to the soil and risks contaminating the vegetables grown on the site.
It is important to underscore that Pb content in the water consumed in the city, which is drawn from the subsoil well and distributed to homes without prior analysis or treatment, ranged from 0.
Public Health Service. Atlanta, The influence of rainfall on Pb levels declined in the months following the heaviest precipitation, suggesting a possible dilution effect, since Pb concentration rose again when rainfall was low and remained stable during those months. In Brazil, there is almost no control over Pb pollution sources due to the lack of information on the actual exposure of the population Neves et al. Thus, further research is needed in order to support public health authorities in initiatives to control environmental damage.
The data in this study demonstrate the urgent need for additional studies on the issue, as well as environmental education measures and technical assistance, in order to reduce heavy metal contamination, thereby ensuring food security and water quality.
The water analyzed in the present study exhibited higher Cd, Ni and Pb levels than the maximum allowable limits under Brazilian legislation, indicating the need for a preventive monitoring program and immediate intervention initiatives aimed at the sources of contamination.
Rainfall influences the seasonal variation in heavy metal levels in water, exhibiting a greater effect on Pb concentration and a moderate influence on Cd and Ni. Abrir menu Brasil. Abrir menu. E-mail: laerciosantos18 gmail. Departamento de Agronomia. E-mail: agromccc yahoo. Colegiado de Agronomia. E-mail: mcesarsolos gmail. In this regard, a promising future direction is the exploration of supported metal ensembles e.
Going beyond acetylene hydrochlorination, the herein derived strategy to disentangle metal-support interactions and gain insights into the specific roles of textural and chemical properties of carbon is generally applicable to any carbon-supported metal-catalyzed reaction and thus provides a valuable tool to derive descriptors for a wide range of catalytic applications.
Further details on the catalyst synthesis and the preparation of the carbon supports are provided in the Supplementary Methods. Multiple characterization methods were employed to determine the composition, porosity, and structure of the fresh and used catalysts, as summarized in Supplementary Table 2.
The surface oxygen content and speciation were determined by thermogravimetric analysis TGA in He coupled to mass spectrometry MS. The acidity of the surface oxygen groups was probed via temperature programmed desorption TPD of NH 3.
All characterization techniques and procedures are detailed in the Supplementary Methods. The hydrochlorination of acetylene was evaluated at atmospheric pressure in a continuous-flow fixed-bed reactor set-up, depicted in Supplementary Fig. Quantification of reactants and products, determination of the yield of vinyl chloride, Y VCM , reaction rate, r , turnover frequency, TOF, space-time-yield, STY, and deactivation constants, k D , as well as the evaluation of carbon mass balances was conducted using the protocols detailed in the Supplementary Methods.
All catalytic tests were performed in the absence of mass and heat transfer limitations, as detailed in Supplementary Discussion. The authors declare that the data supporting the findings of this study are available within the article and its Supplementary Information file. Source data are provided with this paper. Zhai, Y. Carbon materials for chemical capacitive energy storage.
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Selina K. You can also search for this author in PubMed Google Scholar. All authors contributed to the writing of the manuscript. Peer review information Nature Communications thanks Simon Podkolzin and the other, anonymous, reviewer s for their contribution to the peer review of this work. Peer reviewer reports are available. Reprints and Permissions. Design of carbon supports for metal-catalyzed acetylene hydrochlorination.
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