A review of exposure assessment methods for epidemiological studies of health effects related to industrially contaminated sites

BACKGROUND: this paper is based upon work from COST Action ICSHNet. Health risks related to living close to industrially contaminated sites (ICSs) are a public concern. Toxicology-based risk assessment of single contaminants is the main approach to assess health risks, but epidemiological studies which investigate the relationships between exposure and health directly in the affected population have contributed important evidence. Limitations in exposure assessment have substantially contributed to uncertainty about associations found in epidemiological studies. OBJECTIVES: to examine exposure assessment methods that have been used in epidemiological studies on ICSs and to provide recommendations for improved exposure assessment in epidemiological studies by comparing exposure assessment methods in epidemiological studies and risk assessments. METHODS: after defining the multi-media framework of exposure related to ICSs, we discussed selected multi-media models applied in Europe. We provided an overview of exposure assessment in 54 epidemiological studies from a systematic review of hazardous waste sites; a systematic review of 41 epidemiological studies on incinerators and 52 additional studies on ICSs and health identified for this review. RESULTS: we identified 10 multi-media models used in Europe primarily for risk assessment. Recent models incorporated estimation of internal biomarker levels. Predictions of the models differ particularly for the routes ‘indoor air inhalation’ and ‘vegetable consumption’. Virtually all of the 54 hazardous waste studies used proximity indicators of exposure, based on municipality or zip code of residence (28 studies) or distance to a contaminated site (25 studies). One study used human biomonitoring. In virtually all epidemiological studies, actual land use was ignored. In the 52 additional studies on contaminated sites, proximity indicators were applied in 39 studies, air pollution dispersion modelling in 6 studies, and human biomonitoring in 9 studies. Exposure assessment in epidemiological studies on incinerators included indicators (presence of source in municipality and distance to the incinerator) and air dispersion modelling. Environmental multi-media modelling methods were not applied in any of the three groups of studies. CONCLUSIONS: recommendations for refined exposure assessment in epidemiological studies included the use of more sophisticated exposure metrics instead of simple proximity indicators where feasible, as distance from a source results in misclassification of exposure as it ignores key determinants of environmental fate and transport, source characteristics, land use, and human consumption behaviour. More validation studies using personal exposure or human biomonitoring are needed to assess misclassification of exposure. Exposure assessment should take more advantage of the detailed multi-media exposure assessment procedures developed for risk assessment. The use of indicators can be substantially improved by linking definition of zones of exposure to existing knowledge of extent of dispersion. Studies should incorporate more often land use and individual behaviour

Influence of liming and nitrogen forms on boron uptake by tobacco

The purpose of this study was to investigate the influence of soil liming and fertilizer nitrogen forms on the availability of soil B and its uptake by tobacco plant. A field experiment was conducted on an acid Typic Haploxeralf soil, located in Pieria, Northern Greece. The experimental design was factorial 3 x 3 with four replications. The first factor included three rates of lime (0, 4000, and 8000 kg/ha limestone) and the second three combinations of nitrogen forms i.e. a) NO3-N 100%, b) NH4-N 100%, c) N03-N 50% plus NH4-N 50%. Tobacco harvesting was done in four cuttings. Composite leaf samples were selected and analysed for B, Ca, and K. At the end of the experiment composite soil samples were also collected from each experimental plot and were analysed for pH, exchangeable cations and available B using the hot 0.01M CaCl2 extraction procedure. The results showed that soil liming increased soil pH proportionally to the amount of limestone applied. Fertilizer N forms did not significantly affect soil pH. Soil liming significantly decreased available B, which was strongly correlated with soil pH negatively. Boron concentration in tobacco leaves was significantly decreased up to deficiency levels being strongly correlated with available B positively but negatively with soil pH. Ca/B ratio was significantly increased indicating B deficiency. This ratio was strongly correlated with soil pH and exchangeable Ca. Fertilizer N forms did not cause any significant influence on B uptake. The latter was also true for potassium

Influence of biosolids application on some soil physical properties

Biosolids land application is a widely accepted option throughout the world because of its beneficial effects on soil chemical and physical properties and crop yield. These effects-e specially those pertaining to soil physical properties-have not been adequately studied in Mediterranean conditions. In a 3-yr field experiment, conducted in a clay loam (Typic Xerochrept) in central Greece, the influence of biosolids application on cotton yield and some physical soil properties was studied. The experimental design was completely randomized blocks with four biosolids rate (0, 10, 30, and 50 ton ha(-1) yr(-1)) and four replicates. We found that after 3 yr of biosolids application, organic matter content, water retention capacity, available water, and infiltration rate significantly increased, whereas bulk density and aggregate instability index decreased. Soil physical properties affected by the SS addition were significantly correlated with organic matter content. Organic matter content was positively correlated with cotton yield, water retention capacity, available water, and infiltration rate and negatively correlated with bulk density and aggregate instability index

Satellite Visible-Near Infrared Reflectance Correlates to Soil Nitrogen and Carbon Content in Three Fields of the Thessaly Plain (Greece)

Surface visible-near infrared (NIR) reflectance of bare soil by remote sensing devices has been used to infer topsoil properties such as organic matter, soil texture, water content, salinity, and crop residue cover. Spectral mapping of soil properties can be ultimately used as a tool for the implementation of site-specific management practices at the field scale or for soil-landscape modeling at a regional scale. The accuracy of prediction of soil properties with satellite imagery is affected by conditions and properties of the soil surface, by radiometric and atmospheric effects, and by spatial and spectral resolutions. In this study, a high-resolution World View 2 image was used to map soil reflectance in three 10-ha fields of differing soil types and textures that were located in different sections of the east Thessaly Plain. Radiance data from four visible-NIR channels were extracted from the same coordinates that soil samples were taken at two soil depths within each field. Point radiance values were correlated to soil organic matter, total carbon (C) and nitrogen (N) contents, their isotopic composition, carbonate content, nitrate content, pH, electrical conductivity, and soil texture that were analyzed in the laboratory. Strong correlation coefficients emerged between green/NIR image reflectance and total soil N, organic matter, and carbonate content across the three fields in both soil depths. The greatest negative correlation coefficient (R-2 = 0.77) was obtained between satellite NIR reflectance and soil N content. More data are needed to verify these relationships, but the results indicated the potential of high-resolution satellite imagery to quantify within-field and regional-scale variability of soil N and C in the Thessaly Plain

Absorção de metais pesados do lodo de esgoto pelo feijoeiro (Phaseolus vulgaris L.) Heavy Metal Uptake Of The Sewage Sludge By Bean Plants(Phaseolus vulgaris L.)

<abstract language="eng">Toxicity and uptake of heavy metals of sewage sludge by beans (Phaseolus vulgaris L.) were evaluated in green house experiments. Treatments consisted of 1,0 ; 2,0 and 5,0% (m/m) of dry sewage sludge, collected from Londrina (Bom Retiro and ETE-Sul) and Curitiba (ETE-Belém and RALF). Bean ( variety IAPAR 57) was sown three times at 0, 120 and 240 days after the treatments have been applied. Contents of Cd, Cr, Co, Cu, Ni, and Pb in bean tissues cultivated with 5,0% (m/m) of all sewage sludge were similar to the control and Ba contents were reduced by increasing the quantity of sewage sludge in the soil. The Zn content in tissue bean incresed from 86 mg kg-1 of control to 462 mg kg-1 by applying 5% (m/m) of sewage sludge in soil, but plant beans did not show toxicity symptons. The addition of 5% (m/m) of sewage sludge increased Mn content in plants, from 193 mg kg-1 of control to 1.960 mg kg-1, showing toxity in bean leaves when the contents were more than 500 mg kg-1. The addition of sewage sludges in soils increased only available Zn carbonate and Cu organic species

Olive yields and tree nutritional status during a four year period without nitrogen and boron fertilization

Nitrogen (N) and boron (B) are mobile elements in soil. Therefore, the application of these nutrients is typically performed annually, as a single dose, or even splitting it into several fractions in the case of N. In olive (Olea europaea L.), however, controversial literature has suggested that yearly application of N may not be required. In the case of B some authors indicated that one single application is sufficient for three or four years. Thus, the effect of these elements on olive yield, leaf N and B concentrations, as well as soil available N and B were investigated during a field trial performed in an olive orchard located in NE Portugal, in which N and B were not applied for four consecutive growing seasons. Fertilizer treatments consisted of the following: the control, which was a ‘complete’ fertilization plan where N and B were included (N+B treatment); –N treatment, with N excluded from the fertilization plan; and –B treatment, with B excluded. Available soil N and B were estimated from a pot experiment with Italian ryegrass (Lolium multiflorum L.) and from chemical laboratory extractions. Olive yield decreased significantly in the –N treatment in comparison to the control. A slight yield reduction in the –B treatment in comparison to the control was also observed. Leaf N and B concentrations decreased significantly in the –N and –B treatments, respectively, in comparison to the N+B treatment. Soil available N and B at the end of the experiment were significantly lower in the –N and –B treatments, respectively, in comparison to the N+B control. The results showed a continuous decrease in olive yield and leaf N and B concentrations, which reflected the reduction in soil available N and B in the treatments lacking the respective nutrient. Therefore, it seems prudent the recommendation of adjusted rates of N and B every year to prevent reduction in tree crop performance and improve nutrient use efficiency