Dr. Tume-Zapata, Pedro

The objective of this study is to ascertain the spatial distribution of Cu, Pb and Zn in order to determine the degree of contamination in urban soils from Talcahuano (Chile) and to identify the influence of possible contamination sources. A total of 420 samples were collected from the study area based on the following criteria: 140 topsoil samples (TS) (0–10 cm), 140 subsoil samples (SS) (10–20 cm) and 140 deep soil samples (DS) (150 cm). The soils were characterized for their physical characteristics such as grain size distribution, pH, organic matter content etc. and the concentrations of Cu, Pb and Zn were analyzed by Atomic Absorption Photospectrometry following Aqua Regia digestion. Correlations combined with spatial analysis were implemented in order to distinguish the sources of the trace metals and whether they are geogenic or anthropogenic of origin. Several simple and robust statistical methods were applied to the data sets in order to evaluate useful and robust background values. The degree of contamination along with the geoaccumulation index, enrichment factors and contamination factors were also evaluated. The median concentrations obtained for the studied trace metals includes: Cu 23.1 mg kg− 1, Pb 10.2 mg kg− 1 and Zn 56.7 mg kg− 1. In general, the concentrations of Cu, Pb and Zn decrease with depth however, in certain sites the subsoil samples (SS) levels show higher concentrations than topsoil samples (TS). A possible explanation could be related to the uncontrolled clandestine landfill sites using both construction material debris and/or industrial solid wastes. Correlation analysis suggests that Cu, Pb and Zn are contributed by external sources. The spatial distribution of Cu, Pb and Zn in topsoil samples (TS) displays a spatial pattern extending along major roadway environments and emission sources. Estimated background values determined with the iterative 2σ-technique yields 43.7 mg kg− 1 for Cu, 17.5 mg kg− 1 for Pb and 91.7 mg kg− 1 for Zn respectively. The geochemical index, enrichment factor and the contamination factor all register a moderate to high contamination level in some of the soil samples.

As a common component of urban ecosystems, urban soils generally have elevated concentrations of potentially hazardous elements originating from both point and diffuse sources of pollution in cities. This study focuses on the port city of Arica in northern Chile, where anthropogenic activities may have led to contamination of the uppermost topsoil layer. The purpose of this study is to (1) establish background content levels of potentially hazardous elements in topsoils of different land uses using different statistical approaches and (2) assess the degree of topsoil pollution and identify the local sources of pollution using multivariate statistical and geostatistical methods. Data from a Chilean Government CONAMA report were analyzed. Geostatistical methods such as kriging were applied to identify the spatial distribution of potential hazards elements. Potentially hazardous elements' background values were determined by median + 2MAD, inflection points within cumulative frequency plots and upper whisker of a Tukey's boxplot. Multivariate statistical methods were applied in the identification of trace metal sources (anthropogenic vs natural origin). Soil pollution assessment was performed using the geoaccumulation index (Igeo), enrichment factor (EF), contamination factor (Cf) and integrated pollution index (IPI). The maps obtained show high baseline values for some elements (As, Cu, Pb and Zn), which denote a clear anthropogenic contribution due to the long period of constant human activities in the study area. Therefore, background values are estimated with the median + 2 × MAD procedure and yielded As (17.4 mg kg− 1), Ba (23.3 mg kg− 1), Cr (13.6 mg kg− 1), Cu (37.4 mg kg− 1), Ni (8.3 mg kg− 1), Pb (313 mg kg− 1), V (101 mg kg− 1) and Zn (235 mg kg− 1). The calculated soil pollution indexes Igeo, EF, Cf and IPI revealed significant ecological impacts. Copper and As are the two trace elements with the highest contaminated soil values; however, Cu, Pb and Zn have greater numbers of soil sample sites in the moderately to heavily contaminated range. The IPI showed extremely high pollution index in ten soil sites in Arica. Moreover, significant differences were observed with different land uses, where soils along the railway line and industrial area are the most polluted.

Purpose: The objectives of this study were (1) to determine the concentrations and background concentrations of Ba, Co, Cr, Mn, and Ni in the urban soils of Talcahuano (Chile); (2) assess the level of contamination in the urban soils based on different pollution indexes; and (3) to identify natural or anthropogenic sources in order to obtain a spatial distribution of the pollutants. Material and methods: A total of 420 samples were collected from the study area as follows: 140 topsoil samples (TS) (0–10 cm), 140 subsoil samples (SS) (10–20 cm), and 140 deep soil samples (DS) (150 cm). The soils were characterized, and the concentrations of Ba, Co, Cr, Mn, and Ni were analyzed by atomic absorption photospectrometry following aqua regia digestion. Correlations and principal component analysis combined with spatial analysis were implemented in order to distinguish the sources and their classification as geogenic or anthropogenic. Several simple and robust statistical methods were applied to datasets in order to explore their potential in the evaluation of a useful and robust background values. The degree of contamination along with the geoaccumulation index, enrichment factor, and contamination factor were also evaluated. Results and discussion: The median concentrations obtained for various elements includes Ba 461 mg kg−1, Co 82.7 mg kg−1, Cr 134 mg kg−1, Mn 311 mg kg−1, and Ni 56.1 mg kg−1. In general, the concentrations of Ba, Co, Cr, Mn, and Ni decrease with depth. Correlations and principal component analysis suggest that Cr, Mn, and Ni are contributed by external sources. The spatial distribution of Cr, Mn, and Ni in TS displays a spatial pattern extending along industrial environments and emission sources. Conclusions: The estimated background values determined with the iterative 2σ-technique includes 536 mg kg−1 for Ba, 95.9 mg kg−1 for Co, 208 mg kg−1 for Cr, 464 mg kg−1 for Mn, and 90.5 mg kg−1 for Ni. The geochemical index, enrichment factor, and the contamination factor register a moderate to considerable contamination in some soil samples.

Tailings usually provide an unfavorable substrate for plant growth because of their multi-stress environment. Plants growing on naturally metal-enriched soils are of particular interest in this perspective, since they are genetically tolerant to high metal concentrations and have an excellent adaptation to extreme conditions. Soil and plant samples were taken in Peru, at a polymetallic mine (mainly Ag, Pb and Cu) in Cajamarca Province, Hualgayoc district. Top soils (0–20 cm) were analyzed for physical and chemical properties by standard methods. Total As, Cu, Pb and Zn concentrations in top soils were determined by ICP–OES. Similar metals in plants were analyzed separately (aerial and root system) by ICP–MS. Translocation Factor (TF) and Shoot Accumulation Factor (SAF) were determined to assess the tolerance strategies developed by these species and to evaluate their potential for phytoremediation purposes. The non-polluted soils had near neutral pH (6.8 ± 0.1), a great content of organic carbon (42 ± 4.0 g kg−1) and a silt loamy texture. Soil and plant samples were taken at four locations (CA1, CA2, CA3, CA4) as well as the local reference topsoil (CA0). The range of total soil values in mg kg−1 is as follows: As 280–1029; Cu 256–2070; Pb 3992–16,060 and Zn 11,550–28,059, respectively. Unusual elevated concentrations of Pb (over 1000 mg kg−1) and TF greater than one were detected in shoots of six different plants species (Ageratina sp., Achyrocline alata (Kunth) DC., Cortaderia hapalotricha Pilg., Epilobium denticulatum Ruiz & Pav., Taraxacum officinale Weber and Trifolium repens Walter). Ageratina sp and E. denticulatum also showed elevated concentrations of Zn (over 10,000 mg kg−1) and TF greater than one in some studied locations. However, the SAF was smaller than one. Controlled-environment studies must be performed to definitively confirm the Pb hyperaccumulation character of the cited plant species.

The contents for six elements (Ba, Cu, Ni, Pb, V and Zn) have been assayed in soils of Manresa, an area famous for its environmental sceneries in Central Catalonia region. This area is affected by a rapid transition from a traditionally agricultural-based economy to an increasingly industrial-based economy, and has formed a complete industrial structure. Twenty-seven soils (topsoil and subsoil) were sampled and heavy metals concentrations were analysed with an inductively coupled plasma-mass spectrometer (ICP-AES) after acid digestion with HNO3 and HCl and Xray fluorescence (XRF). The background values, calculated after the removal of concentrations above the upper whisker for studied metals were in mg·kg-1: Ba: 904, Cu: 43.9, Ni: 38.7, Pb: 35.4, V: 110 and Zn: 131. The enrichment factor also shows enriched samples for Cu, Pb and Zn. The degree of soil contamination was assessed on the basis of geoaccumulation index and upper whisker method. Five percent of the soils was contaminated by at least one trace metal. The heavy metal showing the greatest number of samples with slight enrichment anomalies was Pb. The following data sets were influenced mainly by natural element dispersion and accumulation processes. Only Cu and Pb should be associated to anthropogenic pollution. However, Cu, Pb and Zn are grouped in very similar way with a general pattern increase in the NE direction for Pb and Zn and N for Cu. The relationships between the X-ray fluorescence and aqua regia methods were highly significant for Cu, Ni, Pb and Zn.