Accumulation, distribution pattern and potential contamination of sulphur in vineyard soils of the Valdepeñas protected denomination origin

Soil is the basis for almost all global agriculture and the medium in which most terrestrial biological activity occurs. Viticulture represents an important agricultural practice in the Castilla-La Mancha (CLM) community. In this region, there are several protected denominations of origin (PDO), the largest being Valdepeñas. This paper describes the accumulation pattern of sulphur (S) in the vineyard soils of this PDO. Samples were collected from 90 vineyard soil profiles. Sulphur content was determined using an X-ray Fluorescence spectrometer in the solid mode on a powdered aliquot of each sample. The results indicated that the total S in soils varied from 0.54 to 6.90 (g·kg-1) in surface soil (0-30 cm) and from 0.39 to 2.80 (g·kg-1) on the subsurface layer (30-80 cm). When comparing the mean values of surface horizons to the subsurface horizons, S content lowered as soil depth increased. Kurtosis exceeded 45 % in all cases, which indicates a wide variability of concentrations. These findings can be explained by the continuous fertiliser and fungicide applications (and therefore S) in these production systems. Using the geoaccumulation index (Igeo), most soils were included in Class 0 (Igeo <0) and were, thus, S uncontaminated; only a few points can be considered pollutants. The obtained results should contribute to extend the scarce existing database on S in Mediterranean regions like that herein studied.

An approach for evaluating the bioavailability and risk assessment of potentially toxic elements using edible and inedible plants-the Remance (Panama) mining area as a model

Mining affects the environment, particularly through the persistence of accumulation of tailings materials; this is aggravated under tropical climatic conditions, which favours the release of potentially toxic elements (PTEs) bioavailable to the local flora and fauna and supposing a risk to human health. The Remance gold mine (Panamá), exploited intermittently for more than 100 years, and has remained derelict for over 20 years. Within the area live farmers who carry out subsistence agriculture and livestock activities. The objective of this study has been to study the transference of PTEs in the local agricultural soil-plants system, with the goal of identifying their bioavailability to perform a human risk assessment. The results obtained of the Bioaccumulation coefficient in local plants show very weak to strong absorption of As (< 0.001-1.50), Hg (< 0.001-2.38), Sb (0.01-7.83), Cu (0.02-2.89), and Zn (0.06-5.32). In the case of Cu in grass (18.3 mg kg^-1) and plants (16.9 mg kg^-1) the concentrations exceed the maximum authorised value in animal nutrition for ruminants (10 mg kg^-1). The risk to human health for edible plants exceeds the non-carcinogenic risk for rice, corn, cassava, and tea leaves for Sb (HQ 19.450, 18.304, 6.075, 1.830, respectively), the carcinogenic risk for Cu (CR = 2.3 × 10^-3, 7.7 × 10 ^-4, 1.1 × 10^-3, 1.0 × 10^-3, respectively), and the carcinogenic risk for As in rice, corn and tea leaves (CR = 8 × 10^-5, 3 × 10^-5, 3 × 10^-5, respectively). Urgent measures are needed to alleviate these effects.

Environmental challenges related to cyanidation in Central American gold mining; the Remance mine (Panama)

Mine tailings are a potential source of environmental pollution because they typically contain potentially toxic elements (PTEs) and the residue of chemical compounds used during extraction processes. The Remance gold mine (NW Panama) is a decommissioned mine with mining activity records dating from the 1800s and several periods of abandonment. Very little remediation work has been performed, and waste is exposed to climatic conditions. This study aimed to evaluate the PTEs and cyanide contents in mine waste after mining operations ceased some 20 years ago, and to evaluate the degree of pollution and the environmental risks they pose with the use of the Pollution Load Index (PLI) and the Ecological Risk Index (RI). Although the total cyanide (T-CN) concentration (1.4-1.9 mg kg^-1) found in most of the study area falls within the limits of gold mining tailing values for American sites (1.5-23 mg kg^-1), it is worth noting that the values of the tailings of the last used mining operation exceed it (25.2-518 mg kg^-1) and persist at the site. The PLI and RI suggest that the tailings from the mine and mine gallery sediments represent a source of pollution for soils and surrounding areas given their high content of PTEs (As, Cu, Sb, Hg) and T-CN, which pose serious ecological risks for biota. Therefore, it is necessary to draw up a remediation plan for this area.

Modeling and Assessing Potential Soil Erosion Hazards Using USLE and Wind Erosion Models in Integration with GIS Techniques: Dakhla Oasis, Egypt

Soil erosion modeling is becoming more significant in the development and implementation of soil management and conservation policies. For a better understanding of the geographical distribution of soil erosion, spatial-based models of soil erosion are required. The current study proposed a spatial-based model that integrated geographic information systems (GIS) techniques with both the universal soil loss equation (USLE) model and the Index of Land Susceptibility to Wind Erosion (ILSWE). The proposed Spatial Soil Loss Model (SSLM) was designed to generate the potential soil erosion maps based on water erosion and wind erosion by integrating factors of the USLE and ILSWE models into the GIS environment. Hence, the main objective of this study is to predict, quantify, and assess the soil erosion hazards using the SSLM in the Dakhla Oasis as a case study. The water soil loss values were computed by overlaying the values of five factors: the rainfall factor (R-Factor), soil erodibility (K-Factor), topography (LS-Factor), crop types (C-Factor), and conservation practice (P-Factor). The severity of wind-driven soil loss was calculated by overlaying the values of five factors: climatic erosivity (CE-Factor), soil erodibility (E-Factor), soil crust (SC-Factor), vegetation cover (VC-Factor), and surface roughness (SR-Factor). The proposed model was statistically validated by comparing its outputs to the results of USLE and ILSWE models. Soil loss values based on USLE and SSLM varied from 0.26 to 3.51 t ha−1 yr−1 with an average of 1.30 t ha−1 yr−1 and from 0.26 to 3.09 t ha−1 yr−1 with a mean of 1.33 t ha−1 yr−1, respectively. As a result, and according to the assessment of both the USLE and the SSLM, one soil erosion class, the very low class (<6.7 t ha−1 yr−1), has been reported to be the prevalent erosion class in the study area. These findings indicate that the Dakhla Oasis is slightly eroded and more tolerable against water erosion factors under current management conditions. Furthermore, the study area was classified into four classes of wind erosion severity: very slight, slight, moderate, and high, representing 1.0%, 25.2%, 41.5%, and 32.3% of the total study area, respectively, based on the ILSWE model and 0.9%, 25.4%, 43.9%, and 29.9%, respectively, according to the SSLM. Consequently, the Dakhla Oasis is qualified as a promising area for sustainable agriculture when appropriate management is applied. The USLE and ILSWE model rates had a strong positive correlation (r = 0.97 and 0.98, respectively), with the SSLM rates, as well as a strong relationship based on the average linear regression (R2 = 0.94 and 0.97, respectively). The present study is an attempt to adopt a spatial-based model to compute and map the potential soil erosion. It also pointed out that designing soil erosion spatial models using available data sources and the integration of USLE and ILSWE with GIS techniques is a viable option for calculating soil loss rates. Therefore, the proposed soil erosion spatial model is fit for calculating and assessing soil loss rates under this study and is valid for use in other studies under arid regions with the same conditions.

Ecological and Health Risk Assessments of an Abandoned Gold Mine (Remance, Panama): Complex Scenarios Need a Combination of Indices

The derelict Remance gold mine is a possible source of pollution with potentially toxic elements (PTEs). In the study area, diverse mine waste has been left behind and exposed to weather conditions, and poses risks for soil, plants and water bodies, and also for the health of local inhabitants. This study sought to perform an ecological and health risk assessment of derelict gold mining areas with incomplete remediation, including: (i) characterizing the geochemical distribution of PTEs; (ii) assessing ecological risk by estimating the pollution load index (PLI) and potential ecological risk index (RI); (iii) assessing soil health by dehydrogenase activity; and iv) establishing non-carcinogenic (HI) and carcinogenic risks (CR) for local inhabitants. Soil health seems to depend on not only PTE concentrations, but also on organic matter (OM). Both indexes (PLI and RI) ranged from high to extreme near mining and waste accumulation sites. As indicated by both the HI and CR results, the mining area poses a health risk for local inhabitants and particularly for children. For this reason, it will be necessary to set up environmental management programs in the areas that are most affected (tailings and surrounding areas) and accordingly establish the best remediation strategies to minimize risks for the local population.

Assessment of urban environmental quality through the measurement of lead in bryophytes: case study in a medium-sized city

The use of bryophytes as an indicator of environmental quality has been addressed on numerous occasions and in different places of the world under a variety of conditions. However, in Latin America their use is still limited. In the study described here, the presence and distribution of the bioaccumulation of lead in bryophytes has been evaluated in both contaminated and uncontaminated sites in Villavicencio (Colombia) and its surroundings. Villavicencio is a medium-sized city that is similar in size to many other cities in Latin America. A total of 52 samples of bryophytes were collected, of which 43 belong to points distributed in urban areas of the city (residential, commercial, highway), and the remaining nine are from uncontaminated areas (reference) taken in the surroundings of the city. The samples were treated with acid (nitric and hydrochloric) and subsequently measured by atomic absorption spectrometry. It was found that Pb concentrations in the commercial sector are between 1 and 6 times higher than in the residential and highway sectors. Spatial distribution maps of lead over the sampled territory were created using Arc-GIS 10.1. It is noteworthy that the values obtained are higher than those found in European cities.

Geochemical distribution of major and trace elements in agricultural soils of Castilla-La Mancha (central Spain): finding criteria for baselines and delimiting regional anomalies

Castilla-La Mancha (central Spain) is a region characterized by significant agricultural production aimed at high-quality food products such as wine and olive oil. The quality of agricultural products depends directly on the soil quality. Soil geochemistry, including dispersion maps and the recognition of baselines and anomalies of various origins, is the most important tool to assess soil quality. With this objective, 200 soil samples were taken from agricultural areas distributed among the different geological domains present in the region. Analysis of these samples included evaluation of edaphological parameters (reactivity, electrical conductivity, organic matter content) and the geochemistry of major and trace elements by X-ray fluorescence. The dataset obtained was statistically analyzed for major elements and, in the case of trace elements, was normalized with respect to Al and analyzed using the relative cumulative frequency (RCF) distribution method. Furthermore, the geographic distribution of analytical data was characterized and analyzed using the kriging technique, with a correspondence found between major and trace elements in the different geologic domains of the region as well as with the most important mining areas. The results show an influence of the clay fraction present in the soil, which acts as a repository for trace elements. On the basis of the results, of the possible elements related with clay that could be used for normalization, Al was selected as the most suitable, followed by Fe, Mn, and Ti. Reference values estimated using this methodology were lower than those estimated in previous studies.

Environmental assessment of potential toxic trace element contents in the inundated floodplain area of Tablas de Daimiel wetland (Spain)

Contamination of aquatic systems with potentially toxic trace elements (PTEs) is a major problem throughout the world. The National Park Tablas de Daimiel (NPTD) is considered to make up one of the two most important wetlands in the Biosphere Reserve called "Wet Spot." Since PTEs are good indicator of the prevailing environmental conditions and possible contamination, soil samples collected from 43 sites were analyzed in order to investigate the levels and its distribution of these elements, in the inundated floodplain area of the NPTD wetland. In addition, some physicochemical parameters such as pH, electrical conductivity and organic matter were measured. The total concentrations of 32 trace elements were determined by X-ray fluorescence. The results show that there was accumulation of lead (Pb), tin (Sn), selenium (Se), antimony (Sb), copper (Cu), vanadium (V), nickel (Ni), zinc (Zn), arsenic (As), strontium (Sr) and zirconium (Zr)-in some cases at high concentrations. The interpolated maps showed that the distributions of some of these elements and in some cases the trend in spatial variability are pronounced and decrease from the inlet to the outlet. The values for some elements are higher than the reference values, which is consistent with contamination (some values are higher by a factor of more than 10 compared to the reference). In the case of iodine (I), the levels at some sample points are significantly more than ten times the reference; Se appears in the range from 1.0 to 9.8 mg/kg, with an average value of 3.1 mg/kg, and these can be considered as seleniferous soils. The concentrations found are consistent with the introduction in the wetland of pollution by human activities, such as agricultural non-point sources, uncontrolled fertilization over many years, treatment with urban wastewater and other possible sources.