Levels of metals, PCBs, PCNs and PAHs in soils of a highly industrialized chemical/petrochemical area: temporal trend

In 2005, the concentrations of various metals and organic pollutants were analyzed in soils collected in different areas of Tarragona (Catalonia, Spain), where an important chemical/petrochemical complex is located. The levels of seven elements (As, Cd, Cr, Hg, Mn, Pb and V), as well as those of polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs) and polycyclic aromatic hydrocarbons (PAHs) were determined in soils, and compared with those obtained in a background study carried out in 2002. Only Cd and Pb showed significant higher concentrations in the petrochemical zone, while no significant differences were found for the remaining elements. In turn, vanadium was the only element showing a significant increase in the concentration between 2002 and 2005. With regard to the organic pollutants, no significant differences were found according to the area of sampling. However, an increase in naphthalene levels was observed during the period 2002-2005 in soils of the chemical and petrochemical areas. According to the present results, it is suggested that the levels of vanadium must be periodically monitored to assure that the important industrialization of Tarragona does not mean health risks for the population living near the complex.     

Monitoring PCDD/Fs and other organic substances in workers of a hazardous waste incinerator: a case study

The aim of this study was to measure, 6 years after regular operations, the concentrations of a number of organic substances in blood and urine of 19 workers employed at a hazardous waste incinerator (HWI) in Spain, and to establish the temporal variation with respect to baseline data and previously performed surveys. This facility was the first, and so far the only HWI in that country. The levels of hexachlorobenzene (HCB), polychlorinated biphenyls (PCB 28, 52, 101, 138, 153 and 180) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in six composite plasma samples, while concentrations of di-, tri, and pentachlorophenols, as well those of 1-hydroxypyrene were measured in the urine of these workers. The current mean PCDD/F concentration, 10.4 ng I-TEQ/kg lipid, was significantly lower than that found in the baseline survey, 26.7 ng I-TEQ/kg lipid and similar to that found in the previous (2004) study (7.7 ng I-TEQ/kg lipid). PCDD/F levels in plasma were similar or even lower than those recently reported for various non-exposed populations. For the remaining analyzed substances in plasma and urine, there was not any significant increase in comparison with the levels found in the baseline survey. On the other hand, no marked differences between the concentrations of organic substances in plasma or urine were found according to the respective workplace (plant, laboratory and administration). The results of the present survey indicate that after 6 years of regular operation, the workers at the HWI are not occupationally exposed to PCDD/Fs and other organic substances in their workplaces.     

A neural-fuzzy approach to classify the ecological status in surface waters

A methodology based on a hybrid approach that combines fuzzy inference systems and artificial neural networks has been used to classify ecological status in surface waters. This methodology has been proposed to deal efficiently with the non-linearity and highly subjective nature of variables involved in this serious problem. Ecological status has been assessed with biological, hydro-morphological, and physicochemical indicators. A data set collected from 378 sampling sites in the Ebro river basin has been used to train and validate the hybrid model. Up to 97.6% of sampling sites have been correctly classified with neural-fuzzy models. Such performance resulted very competitive when compared with other classification algorithms. With non-parametric classification-regression trees and probabilistic neural networks, the predictive capacities were 90.7% and 97.0%, respectively. The proposed methodology can support decision-makers in evaluation and classification of ecological status, as required by the EU Water Framework Directive.     

Distribution and temporal variation of trace metal enrichment in surface sediments of San Jorge Bay, Chile

Cu, Pb, and Hg concentrations were determined in surface sediment samples collected at three sites in San Jorge Bay, northern Chile. This study aims to evaluate differences in their spatial distribution and temporal variability. The highest metal concentrations were found at the site “Puerto”, where minerals (Cu and Pb) have been loaded for more than 60 years. On the other hand, Hg does not pose a contamination problem in this bay. Cu and Pb concentrations showed significant variations from 1 year to another. These variations seem to be a consequence of the combination of several factors, including changes in the loading and/or storage of minerals in San Jorge Bay, the dredging of bottom sediments (especially at Puerto), and seasonal changes in physical–chemical properties of the water column that modify the exchange of metals at the sediment–water interface. Differences in the contamination factor and geoaccumulation index suggest that pre-industrial concentrations measured in marine sediments of this geographical zone, were better than geological values (average shale, continental crust average) for evaluating the degree of contamination in this coastal system. Based on these last two indexes, San Jorge Bay has a serious problem of Cu and Pb pollution at the three sampling locations. However, only Cu exceeds the national maximum values used to evaluate ecological risk and the health of marine environments. It is suggested that Chilean environmental legislation for marine sediment quality—presently under technical discussion—is not an efficient tool for protecting the marine ecosystem.     

Long-term environmental monitoring of persistent organic pollutants and metals in a chemical/petrochemical area: human health risks

Organic pollutants such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs) and polycyclic aromatic hydrocarbons (PAHs), as well as some metals are periodically monitored in soil and vegetation samples collected in Tarragona County (Spain). We here report the temporal trends of the concentrations of the above pollutants between the initial survey (2002) and that recently (2009) performed. The area under evaluation was divided into 4 sections (chemical, petrochemical, urban/residential and unpolluted). In general terms, urban soils presented the highest concentrations of PCDD/Fs, PCNs and PAHs, confirming that traffic is a very important emission source of these pollutants. In addition, substantially higher levels of PAHs and some metals were found in vegetation samples from the petrochemical complex. The assessment of health risks of these contaminants indicated that the current concentrations of micropollutants did not mean additional non-carcinogenic or cancer risks for the population living in the zone.     

Monitoring dioxins and furans in the vicinity of an old municipal waste incinerator after pronounced reductions of the atmospheric emissions

In order to get an overall picture of the environmental impact of an old municipal solid waste incinerator (MSWI) from S. Adrià del Besòs (Barcelona, Catalonia, Spain), a monitoring program addressed at determining the levels of a number of pollutants in the vicinity of the facility was initiated in 1998. In March 1999, an adaptation was carried out due to EU legislation on pollutant emissions from the stack. As a result, emissions of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were notably reduced, and a significant (30%) decrease was found in the levels of PCDD/F in herbage samples collected in the vicinity of the MSWI. In March 2001, herbage samples were collected at the same sampling points and the PCDD/F levels measured again. The current PCDD/F concentrations range from 0.23 to 1.43 ng I-TEQ kg(-1) (dry matter), with median and mean values of 0.58 and 0.66 ng I-TEQ kg(-1) (dry matter), respectively, while in the 2000 survey the PCDD/F concentrations ranged from 0.22 to 1.20 ng I-TEQ kg(-1) (dry matter), with median and mean values of 0.57 and 0.61 ng I-TEQ kg(-1) (dry matter), respectively. Although the current PCDD/F concentrations in herbage samples are comparable to those found in recent surveys carried out in various places of Catalonia, an exhaustive evaluation of the data, including principal component analysis, indicates that other emission sources of PCDD/Fs also have a notable environmental impact on the area under direct influence of the MSWI.     

Neurological and neuropsychological deterioration in artisanal gold miners from the town of Andacollo,Chile

It is widely known that human exposure to mercury vapor can cause neurological and neuropsychological deterioration. We have investigated if a population of Chilean artisanal gold-mining workers heavily exposed to elemental mercury (Hg⁰) display neurological and neuropsychological impairment. Male volunteers occupationally exposed to Hg⁰ (“gold miners”, n = 35) were recruited and compared with a group of unexposed workers (n = 40). Blood specimens were obtained from both groups for total mercury quantification. Upon neurological examination, 71% of the “gold miners” group showed abnormalities expressed as frontal impairment, tremor, or simultaneously frontal impairment, parkinsonism, and pyramidal syndrome. In contrast, only 16% of the individuals in the control group displayed neurological abnormalities. The “gold miners” group also showed impairment of the neuropsychological performance and the distribution of abnormal scores for almost all the neuropsychological tests applied was significantly higher in this group compared to the control group. Educational level, alcohol intake, and smoking habits did not influence the outcome of the neurological or neuropsychological examinations. Finally, despite that the higher blood mercury concentrations were found in the “gold miners” group, they were not significantly different from the values obtained in the control group.     

Observations on metal trends in soil and vegetation samples collected in the vicinity of a hazardous waste incinerator under construction (1996–1998)

The temporal variation in metal concentrations in soil and vegetation samples collected in an area of Catalonia (Spain), which will be under the potential influence of a new hazardous waste incinerator was determined. In 1996 and again in 1998, As, Be, Cd, Cr, Hg, Mn, Ni, Pb, Sn, Tl and V were measured in 40 soil and 40 herbage samples collected at 250–4000 m from the facility at the same sampling points. Data of both surveys and the percentages of variation are here presented for all metals. Results are shown according to the main wind directions in the area, as well as distances from the new facility. During the period 1996–1998, a general decrease was noted for most metals. Only the levels of Hg were significantly increased during this period. The present results will be useful for future surveys aimed to evaluate the environmental impact of metals derived from emissions of the new plant.     

Levels of metals in soils of Alcalá de Henares,Spain: human health risks

The concentrations of aluminium (Al), arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), tin (Sn), thallium (Tl), vanadium (V), and zinc (Zn) were determined in soil samples collected in Alcalá de Henares (Madrid, Spain). Human health risks derived from metal inhalation and ingestion of soils were also assessed. For noncarcinogenic risks, the current levels of metals were usually lower than those considered as safe for the general population. With respect to the potentially carcinogenic elements As, Be, Cd, and Cr, the concentrations of Be, Cd, and Cr were lower than the reference values, while the average As concentration (3.4 microg/g) was higher than the safety limit for risk cancer. In general terms, the potential human health impact of ingestion/inhalation through soils of the analyzed elements seems to be rather small.     

Annual variation in the levels of metals and PCDD/PCDFs in soil and herbage samples collected near a cement plant

In May 2000, the levels of a number of metals (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sn, Tl, V and Zn) and polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in soil and herbage samples collected near a cement plant from Sta. Margarida i els Monjos (Catalonia, Spain). To determine the temporal variation in the concentrations of metals and PCDD/PCDFs, in May 2001 soil and herbage samples were again collected at the same sampling points and analyzed for the levels of metals and PCDD/PCDFs. In general terms, metal concentrations in soils did not change between May 2000 and May 2001, while significant decreases in the levels of Cr, Ni and V were found in herbage. On the other hand, no significant differences in the mean I-TEQ values of PCDD/PCDFs were found in soil and herbage samples. The results of this survey show that according to the annual variation in the levels of metals and PCDD/PCDFs the environmental impact of the cement plant on the area under its direct influence is not relevant.