Search results for "nitrate"

Geochemical characterization and health risk assessment in two diversified environmental settings (Southern Italy).

2021

An integrated approach using chemical and microbial indicators has been tested in two different sites of the Campania Plain (Southern Italy) with different land use covering and different hydrogeological features in order: (1) to define the water-rock interaction processes, (2) to differentiate sources of pollution in a detailed way (3) to evaluate the degree of water quality in the studied alluvial aquifer and (4) to identify the most worrying elements for human's health. Groundwater have showed a HCO3-Ca signature for both investigated sites, and a progressive enrichment in alkali ions has been highlighted moving from the boundary of the plain toward the coastal areas, due to groundwater …

Analytical method, pattern and sources of polycyclic aromatic hydrocarbons (PAHs) in the stone of the Temples of Agrigento (Italy)

2009

Abstract This study shows the extraction and analytical conditions for the determination of polycyclic aromatic hydrocarbons (PAHs) in the stone of archaeological and historical interest. The aim of this research was to determine the concentrations, distribution and the main sources of PAHs present in the surface layer of stone of the Temples of Agrigento. Together with PAHs, we analyzed sulphates and nitrates since it has been demonstrated that these are very destructive salts that play an important role in the deterioration of stones. Total PAHs at different sites of the Valley of Temples at Agrigento varied from 18 to 84 μg/kg. Analyses were performed by GC–MS. The relative abundance of …

Reduction of Nitrates in Waste Water through the Valorization of Rice Straw: LIFE LIBERNITRATE Project

2018

An improved and more sustainable waste management system is required for successful development of technologies based on renewable sources. Rice straw is submitted to controlled combustion reactions and the produced ashes are chemically treated to produce silica. After a chemical activation step, the activated silica shows potential as an adsorbent agent and will be used to remove the excess of nitrates in groundwater and wells in the area of Alginet (Valencia, Spain), selected as a vulnerable zone within the Nitrates Directive. The demonstration activity aims to have a local impact on municipalities of 200 inhabitants or fewer, decreasing from current nitrate concentrations close to 50 mg/…

Status Mutu Kualitas Air Laut Pantai Maruni Kabupaten Manokwari

2017

Penelitian ini bertujuan untuk mengetahui konsentrasi Amonia, Nitrat dan Ortoposfat serta parameter lainnya yang tertera pada baku mutu air laut untuk biota laut dan mengetahui status mutu kualitas air laut dengan menggunakan metode Indeks Pencemaran (IP). Konsentrasi ammonia dan nitrat dari dua periode pengamatan dalam satu wilayah Pantai Maruni secara konsisten menunjukkan hasil yang melebihi nilai ambang batas baku mutu lingkungan, sedangkan ortofosfat pada semua titik sampling masih dibawah nilai ambang batas baku mutu lingkungan sesuai Keputusan Menteri Lingkungan Hidup No. 51 Tahun 2004 tentang Baku Mutu Air Laut. Status mutu kualitas air laut Pantai Maruni berdasarkan analisis Indeks…

The Impact of the Changing Climate on the Supply and Recycling of Nitrate

2009

A high proportion of the nitrogen found in lakes and rivers is present in the form of nitrate. The concentration of nitrate in many surface waters has increased over the last forty years (OECD, 1982; Roberts and Marsh, 1987; Johnes and Burt, 1993). The main source of nitrate is diffuse drainage from agricultural land (Vinten and Smith, 1993) but point sources can be important in populated areas (Jarvey et al., 1998). In 1991, the European Union introduced the Nitrates Directive (91.676) to protect waters from pollution by nitrate leached from agricultural land.

Hydrothermal Synthesis of ZnO Crystals from Zn(OH)2 Metastable Phases at Room to Supercritical Conditions

2014

The originality of this work is to highlight the effect of temperature and pressure on the size and morphology of hydrothermal ZnO particles from ambient to supercritical conditions (T > 374 °C and P > 221 bar) using a unique continuous one-step process. Experiments were carried out from zinc nitrate (Zn(NO3)2) and potassium hydroxide (KOH) solutions in the ranges of 1–300 bar and 30–400 °C. The as-prepared particles of ZnO (flower, ellipsoid, and sphere) and e-Zn(OH)2 (polyhedral) sized from nano to micrometers were characterized by X-ray diffraction and electronic microscopy. The wulfingite phase (e-Zn(OH)2) was detected inside some powders especially at room temperature for higher pressu…

Analysis of toxic elements in plastic components for toys. Multi-elemental determination by x-ray fluorescence

1993

Abstract An x-ray fluorescence method is proposed for the multi-elemental determination of toxic elements in plastic articles for children, viz., Sb(III), Ba, Cd, Cr(III), Hg, Pb and As(III). Mineralization is achieved by using molten sodium hydroxide to decompose the organic matrix, with sodium nitrate as auxiliary oxidant. Stable solutions containing the chemical species for analysis are obtained. The species are separated from the solution by (co)precipitation, in a medium of NH+4-NH3 buffer (pH 8.5) with sodium diethyldithiocarbamate, sodium rhodizonate and Fe3+, which acts as a carrier. The precipitates deposited on filter-paper are placed in the x-ray spectrometer in fine layer morpho…

Importance of Sodium Nitrate in the Maturation Process of Gouda Cheese

2011

The aim of this study was to observe the dynamics of sodium nitrate during ripening, in was introduced in different amounts in the recipe. Sodium nitrate is the chemical compound also known as Chile saltpeter or Peru saltpeter, is used as an ingredient as a food preservative. Sodium nitrate should not be confused with the related compound, sodium nitrite. Sodium nitrate in the cheese gives a longer time of preservation (Moore J.C., 2010).

Ab Initio Study on the Mechanism of Tropospheric Reactions of the Nitrate Radical with Alkenes:  Propene

2000

Oxidative lung injury correlates with one-lung ventilation time during pulmonary lobectomy: a study of exhaled breath condensate and blood.

2015

OBJECTIVES: During lung lobectomy, the operated lung is collapsed and hypoperfused; oxygen deprivation is accompanied by reactive hypoxic pulmonary vasoconstriction. After lung lobectomy, ischaemia present in the collapsed state is followed by expansion–reperfusion and lung injury attributed to the production of reactive oxygen species. The primary objective of this study was to investigate the time course of several markers of oxidative stress simultaneously in exhaled breath condensate and blood and to determine the relationship between oxidative stress and one-lung ventilation time in patients undergoing lung lobectomy. METHODS: This single-centre, observational, prospective study includ…