Degree of phosphorus saturation of an Oxisol amended with biosolids in a long-term field experiment

When applied to agricultural soils, phosphate fertilizers and the mineral or organic compounds present in solid and/or liquid waste may raise phosphorus (P) content and increase soil P saturation. The degree of phosphorus saturation (DPS) is a good indicator of potential P loss from agricultural soils. The purpose of this study was to calculate the DPS of samples from an Oxisol amended for 5 years with biosolids and mineral fertilizer. DPS was calculated based on P, iron, and aluminum extracted by ammonium oxalate and oxalic acid (DPS_ox) or by Mehlich-1 solution (DPS_M1). Treatments included NPK mineral fertilization (175 kg ha^?1 of P), B1?=?19.02 t ha^?1 of biosolids (350 kg ha^?1 of P), B2?=?38.17 t ha^?1 of biosolids (703 kg ha^?1 of P), B3?=?76.26 t ha^–1 of biosolids (1,405 kg ha^?1 of P), and a control (no P added). Water-extractable P (WEP) was also measured. Critical levels of DPS_ox and DPS_M1 (21 and 24 %, respectively) were only achieved in the topsoil (0–0.1 m) at the highest biosolid dose. Concentration of WEP was positively correlated to DPS_ox and DPS_M1. The DPS_M1 method may be an alternative to DPS_ox for assessing the environmental risk of P loss from soil into surface runoff.     

Indoor pollution and burning practices in wood stove management

This study evaluates effects of good burning practice and correct installation and management of wood heaters on indoor air pollution in an Italian rural area. The same study attests the role of education in mitigating wood smoke pollution. In August 2007 and winters of 2007 and 2008, in a little mountain village of Liguria Apennines (Italy), indoor and outdoor benzene, toluene, ethylbenzene, and xylene (BTEX) concentrations were measured in nine wood-heated houses. During the first sampling, several mistakes in heating plant installations and management were found in all houses. Indoor BTEX concentrations increased during use of wood burning. Low toluene/benzene ratios were in agreement with wood smoke as main indoor and outdoor pollution source. Other BTEX sources were identified as the indoor use of solvents and paints and incense burning. Results obtained during 2007 were presented and discussed with homeowners. Following this preventive intervention, in the second winter sampling all indoor BTEX concentrations decreased, in spite of the colder outdoor air temperatures. Information provided to families has induced the adoption of effective good practices in stoves and fire management. These results highlight the importance of education, supported by reliable data on air pollution, as an effective method to reduce wood smoke exposures.

Implications:Information about burning practices and correct installation and management of wood heaters, supported by reliable data on indoor and outdoor pollution, may help to identify and remove indoor pollution sources. This can be an effective strategy in mitigate wood smoke pollution.     

Volatile Organic Compounds from Coal Tar and Soil Vapor Samples at MGP Sites

This study characterized organic compounds found in New York State manufactured gas plant (MGP) coal tar vapors using controlled laboratory experiments from four separate MGP sites. In addition, a limited number of deep (0.3–1.2 m above coal tar) and shallow (1.2–2.4 m above coal tar) soil vapor samples were collected above the in situ coal tar source at three of these sites. A total of 29 compounds were consistently detected in the laboratory-generated coal tar vapors at 50°C, whereas 24 compounds were detected at 10°C. The compounds detected in the field sample results were inconsistent with the compounds found in the laboratory-generated samples. Concentrations of compounds in the shallow soil vapor sample were either non-detectable or substantially lower than those found in deeper samples, suggesting attenuation in the vadose zone. Laboratory-generated data at 50°C compared the (% non-aromatic)/(% aromatic) ratio and indicated that this ratio may provide good discrimination between coal tar vapor and common petroleum distillates.     

A hybrid biological process of indoor air treatment for toluene removal

Bioprocesses, such as biofiltration, are commonly used to treat industrial effluents containing volatile organic compounds (VOCs) at low concentrations. Nevertheless, the use of biofiltration for indoor air pollution (IAP) treatment requires adjustments depending on specific indoor environments. Therefore, this study focuses on the convenience of a hybrid biological process for IAP treatment. A biofiltration reactor using a green waste compost was combined with an adsorption column filled with activated carbon (AC). This system treated a toluene-micropolluted effluent (concentration between 17 and 52 µg/m³), exhibiting concentration peaks close to 733 µg/m³ for a few hours per day. High removal efficiency was obtained despite changes in toluene inlet load (from 4.2 × 10^?3 to 0.20 g/m³/hr), which proves the hybrid system’s effectiveness. In fact, during unexpected concentration changes, the efficiency of the biofilter is greatly decreased, but the adsorption column maintains the high efficiency of the entire process (removal efficiency [RE] close to 100%). Moreover, the adsorption column after biofiltration is able to deal with the problem of the emission of particles and/or microorganisms from the biofilter.

ImplicationsIndoor air pollution is nowadays recognized as a major environmental and health issue. This original study investigates the performance of a hybrid biological process combining a biofilter and an adsorption column for removal of indoor VOCs, specifically toluene.     

Agricultural adjustment,population dynamics and forests redistribution in a subtropical watershed of NW Argentina

Patterns of land-use and land-cover change are usually grouped into one of two categories defined by the dominant trend: (1) deforestation resulting from expanding agriculture and (2) forest expansion, usually related to the abandonment of marginal lands. At regional scale, however, both processes can occur simultaneously even in the absence of net change. Given the focus on net change, such redistribution of agricultural and natural and seminatural lands has been generally overlooked. The interaction between agriculture modernization, human demography and complex topographic gradients of northwestern Argentina has resulted in processes of both forest recovery and deforestation, thus providing the opportunity to analyze patterns and driving forces of land-cover redistribution. We analyzed 20 years (1986–2006) of land-cover change in a subtropical watershed in relation to topographic and demographic variables. Although net forest change represented <1 %, forests redistribution affected 7 % of forest lands. There was a consistent geographic segregation of deforestation and forest recovery, with forests expanding over steep highlands and agriculture expanding over lowland irrigated areas. Population trends were not associated to forest expansion in lowlands but they explained 32 % of forest recovery in highlands. Highland forest expansion and lowland deforestation, respectively, imply conservation opportunities for humid montane forests and the environmental services they provide (e.g., watershed conservation) and threats for the conservation of dry forests and its biodiversity. Our study exemplifies the importance of land-use redistribution (rather than net change) with relevant environmental consequences at regional scale.     

Spatial variability of precipitation in Spain

The spatial variability of annual and seasonal precipitation in the conterminous land of Spain has been evaluated by using correlation decay distance analysis (CDD). The CDD analysis essentially explores how the correlation between neighbouring stations varies according to distance. We analysed CDD independently for the decades 1956–1965, 1966–1975, 1976–1985, 1986–1995, and 1996–2005 using only those stations with no missing values for each decade. To this end, 972, 1,174, 1,242, 773 and 695 complete series were used for each decade, respectively. In particular, for each station and decade, we calculated the threshold distance at which the common variance between target (i) and neighbour series is higher than 50 % (r ²  = 0.5) to evaluate whether current density of the climate data set captures the spatial variability of precipitation within the study area. Results indicate that, at an annual scale, neighbouring stations with 50 % of common variance are restricted on average to about 105 km, but this distance can vary from 28 to 251 km within the study area. The lowest variability is located to the SW and in winter, while the higher spatial variability is found to the north, in the Cantabrian area, and to the east, in the Mediterranean and Pyrenees, during summer. Our results suggest that current density of climate stations (those operating in 2005) is good enough to study precipitation variability at an annual scale for winter, spring and autumn, but not enough for summer.     

Contamination levels of polychlorinated biphenyls in wild versus cultivated samples of female and male mussels (Mytilus sp.) from the Northwest Coast of Iberian Peninsula—new application for QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) methodology

A newly analytical method based on QuEChERS extraction followed by gas chromatography with mass spectrometry (GC-MS) analysis was developed and validated for the quantification of 18 PCBs in wild (from Matosinhos Beach, Portugal) and cultivated (from Ria de Arousa, Spain) mussel samples, pooled by sex. Wild animals showed higher PCB levels than cultivated mussels, with males from both origins, presenting an upper contamination profile comparing with females. This fact seems to be correlated with few biometric parameters, but other interdependencies, not addressed herein, such as distinct lipid contents between sexes, as a consequence of the gametogenic stage, may also explain this data. Overall, data reiterate the importance of investigating the presence of PCBs in marine biological samples, which can act both as bioindicators of environmental contamination, either as food quality controls for human health.     

Bioremediation assessment of diesel–biodiesel-contaminated soil using an alternative bioaugmentation strategy

This study investigated the effectiveness of successive bioaugmentation, conventional bioaugmentation, and biostimulation of biodegradation of B10 in soil. In addition, the structure of the soil microbial community was assessed by polymerase chain reaction-denaturing gradient gel electrophoresis. The consortium was inoculated on the initial and the 11th day of incubation for successive bioaugmentation and only on the initial day for bioaugmentation and conventional bioaugmentation. The experiment was conducted for 32 days. The microbial consortium was identified based on sequencing of 16S rRNA gene and consisted as Pseudomonas aeruginosa, Achromobacter xylosoxidans, and Ochrobactrum intermedium. Nutrient introduction (biostimulation) promoted a positive effect on microbial populations. The results indicate that the edaphic community structure and dynamics were different according to the treatments employed. CO₂ evolution demonstrated no significant difference in soil microbial activity between biostimulation and bioaugmentation treatments. The total petroleum hydrocarbon (TPH) analysis indicated a biodegradation level of 35.7 and 32.2 % for the biostimulation and successive bioaugmentation treatments, respectively. Successive bioaugmentation displayed positive effects on biodegradation, with a substantial reduction in TPH levels.     

Use of hairy roots extracts for 2,4-DCP removal and toxicity evaluation by Lactuca sativa test

2,4-Dichlorophenol (2,4-DCP) is widely distributed in wastewaters discharged from several industries, and it is considered as a priority pollutant due to its high toxicity. In this study, the use of different peroxidase extracts for 2,4-DCP removal from aqueous solutions was investigated. Tobacco hairy roots (HRs), wild-type (WT), and double-transgenic (DT) for tomato basic peroxidases (TPX1 and TPX2) were used to obtain different peroxidase extracts: total peroxidases (TPx), soluble peroxidases (SPx), and peroxidases ionically bound to the cell wall (IBPx). All extracts derived from DT HRs exhibited higher peroxidase activity than those obtained from WT HRs. TPx and IBPx DT extracts showed the highest catalytic efficiency values. The optimal conditions for 2,4-DCP oxidation were pH 6.5, H₂O₂ 0.5 mM, and 200 U mL^?1 of enzyme, for all extracts analyzed. Although both TPx extracts were able to oxidize different 2,4-DCP concentrations, the removal efficiency was higher for TPx DT. Polyethylene glycol addition slightly improved 2,4-DCP removal efficiency, and it showed some protective effect on TPx WT after 2,4-DCP oxidation. In addition, using Lactuca sativa test, a reduction of the toxicity of post removal solutions was observed, for both TPx extracts. The results demonstrate that TPx extracts from both tobacco HRs appear to be promising candidate for future applications in removing 2,4-DCP from wastewaters. This is particularly true considering that these peroxidase sources are associated with low costs and are readily available. However, TPx DT has increased peroxidase activity, catalytic efficiency, and higher removal efficiency than TPx WT, probably due to the expression of TPX1 and TPX2 isoenzymes.     

The integrated biomarker response revisited: optimization to avoid misuse

The growing need to evaluate the quality of aquatic ecosystems led to the development of numerous monitoring tools. Among them, the development of biomarker-based procedures, that combine precocity and relevance, is recommended. However, multi-biomarker approaches are often hard to interpret, and produce results that are not easy to integrate in the environmental policies framework. Integrative index have been developed, and one of the most used is the integrated biomarker response (IBR). However, an analysis of available literature demonstrated that the IBR suffers from a frequent misuse and a bias in its calculation. Then, we propose here a new calculation method based on both a more simple formula and a permutation procedure. Together, these improvements should rightly avoid the misuse and bias that were recorded. Additionally, a case study illustrates how the new procedure enabled to perform a reliable classification of site along a pollution gradient based on biomarker responses used in the IBR calculations.