The 87Sr/86Sr ratio of horticultural products
mostly derives from that of the bioavailable Sr fraction of the soil
where they grow and, therefore, varies according to the local geolithological
features. This study investigated the intra- and intertree variability
of the 87Sr/86Sr ratio in two apple orchards
in South Tyrol and its relation with the soil 87Sr/86Sr ratio. In both orchards, a moderate homogeneity of the 87Sr/86Sr ratio was observed among subsamples of
the same tree part (shoot axes, leaves, apple peels, and pulps). Moreover,
the 87Sr/86Sr ratio homogeneity among tree parts
was high intratree and low intertree. The variability of the 87Sr/86Sr ratio within the tree and within the orchard
is explained in light of the 87Sr/86Sr ratios
of the soil. This 87Sr/86Sr variability within
orchards does not preclude its use as a geographical tracer; however,
this aspect should be evaluated to correctly design a sampling campaign
or to generalize the results.
Abstract. Understanding the hydrological and hydrochemical functioning of glacierized
catchments requires the knowledge of the different controlling factors and
their mutual interplay. For this purpose, the present study was carried out
in two sub-catchments of the glacierized Sulden River catchment
(130 km2; eastern Italian Alps) in 2014 and 2015, characterized by a
similarly sized but contrasting geological setting. Samples were taken at
different space and timescales for analysis of stable isotopes in water,
electrical conductivity, and major, minor and trace elements. At the monthly sampling scale, complex spatial and temporal dynamics for
different spatial scales (0.05–130 km2) were found, such as
contrasting electrical conductivity gradients in both sub-catchments.
For the entire
Sulden catchment, the relationship between discharge and electrical
conductivity showed a monthly hysteretic pattern. Hydrometric and geochemical
dynamics were controlled by interplay of meteorological conditions,
topography and geological heterogeneity. A principal component analysis
revealed that the largest variance (36.3 %) was explained by heavy metal
concentrations (such as Al, V, Cr, Ni, Zn, Cd and Pb) during the melting
period, while the remaining variance (16.3 %) resulted from the bedrock
type in the upper Sulden sub-catchment (inferred from electrical
conductivity, Ca, K, As and Sr concentrations). Thus, high concentrations of
As and Sr in rock glacier outflow may more likely result from bedrock
weathering. Furthermore, nivo-meteorological indicators such as daily maximum
air temperature and daily maximum global solar radiation represented
important meteorological controls, with a significant snowmelt contribution
when exceeding 5 ∘C or 1000 W m−2, respectively. These
insights may help in better understanding and predicting hydrochemical
catchment responses linked to meteorological and geological controls and in
guiding future classifications of glacierized catchments according to their
hydrochemical characteristics.
This article presents the case study of a waste incinerator located in a region rich in natural and environmental resources, and close to the city of Bozen, where there are about 100,000 inhabitants. Local authorities paid special attention to the effect of the plant on human health and the surrounding environment. Indeed, among the measures adopted to control the emissions, in 2003 an automatic sampling system was installed specifically to monitor polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/F) emissions during the complete operation time of the plant. The continuous sampling system was coupled directly to aerosol spectrometers for the determination of fine and ultra-fine particles in the emissions of the plant. The measurement results suggest that the waste incineration plant of Bozen is not a significant source of PCDD/F, or fine and ultra-fine particles. Immission measurements from other monitoring systems confirmed these results.
The Sr/Sr ratio of a produce is generally linked with the soil geological features of the growing areas. This study aimed at assessing to which extent the addition of external Sr by agricultural practices, like irrigation and mineral nutrient supply, influences this relationship. In a first experiment, oat plants in two soils reflected the Sr/Sr of the soil. However, this link was significantly altered at increasing levels of external Sr soil supplies. In a second experiment, apple trees transplanted in pots modified their original Sr/Sr, which became progressively closer to the soil Sr isotope ratio. The addition of tap water and fertilizers, with different Sr isotopic signatures, slightly affected plant Sr/Sr. Results confirm the potential of the Sr/Sr ratio as a geographical tracer of agricultural commodities, but whenever the range of Sr/Sr variability among soils from different geographical areas is narrow, the influence of external Sr-sources may smooth over these diversities.
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