The objectives of this study were to assess susceptibility to acidification and nitrogen (N) saturation caused by atmospheric deposition to northeastern US forests, evaluate the benefits and shortcomings of making critical load assessments using regional data, and assess the relationship between expected risk (exceedance) and forest health. We calculated the critical loads of nutrient N and of sulfur (S) + N using the steady-state mass balance method at >4,000 regional and national vegetation and soil monitoring network plots in the northeastern USA. Regional calculations of critical loads necessitate use of soil maps which provide a range for each soil characteristic resulting in a broad range of critical load of S + N and exceedance values. For the scenario most representative of regional conditions, over 80 % of the critical loads fell into the range of 850–2050 eq ha⁻¹ yr⁻¹; at 45 % of the plots, deposition exceeded the critical load. In contrast, the critical load for nutrient N, 200–300 eq ha⁻¹ yr⁻¹, was lower. Site measurements, especially to estimate soil weathering, would increase the certainty of the critical load. We observed significant negative correlations between critical load exceedance and growth (17 species) and crown density (4 species); we observed significant positive correlations of exceedance with declining vigor (four species), with crown dieback (six species) and crown transparency (seven species). Among the species which demonstrate the most significant detrimental responses to atmospheric deposition are balsam fir, red spruce, quaking aspen, and paper birch. These results indicate that significant detrimental responses to atmospheric deposition are being observed across the northeastern USA.

The present work tested effects of a revegetation pattern conducted using Paulownia fortunei (Seem.) Hemsl. (Scrophulariaceae) on soil chemical properties and actinomycete community structure identified by terminal restriction fragment length polymorphism (T-RFLP) technology of 16S rDNA. The results indicated that P. fortunei planting with time effectively improved organic carbon and total nitrogen contents, as well as pH in heavy metal-contaminated soils and, at the same time, enhanced the retention of heavy metals such as Pb, Zn, Cu and Cd in soils. T-RFLP profiles of soil actinomycete communities digested from two restriction enzymes (HhaI and RsaI) showed different specific TRF patterns across four sites with different revegetation time. Nonetheless, number and diversity of terminal restriction fragments for soil actinomycete community increased gradually with P. fortunei planting time and followed consistent patterns with soil organic carbon, total nitrogen, pH and heavy metal contents. Our results revealed a great potential of P. fortunei to remediate heavy metal-contaminated soils.

The aim of this study was to develop (1) a method for the calculation of the maximum legal rate at which meat and bone meal (MBM) and biosolids should be applied to land, which took into account the soil phosphorus (P) index, the dry solids and the nutrient and metal content of each material, and (2) a quick method to evaluate their impact, when applied at the estimated maximum and twice the maximum application rates, on the release of P and metals to surface runoff. Three types of biosolids—lime stabilised (LS), anaerobically digested (AD) and thermally dried (TD)—and two types of MBM (low and high ash) were examined. The nutrient and metal losses were examined using a 1-L capacity beaker, which contained an intact soil core. Treatments were applied at maximum and twice the maximum legal application rates and then overlain with 500 mL of water, which was stirred to simulate overland flow. At the maximum legal application rate, low ash MBM (1.14 mg L⁻¹) and TD biosolids (2.43 mg L⁻¹) had the highest losses of P. Thermally dried biosolids and LS biosolids exceeded maximum allowable concentrations (MAC) for manganese, but all treatments remained below the MAC for copper and iron, at the maximum legal application rate. Anaerobically digested biosolids and high and low ash MBM would appear to have potential for landspreading, but these results are indicative only and should be verified at field scale.

Kinetics and mechanism on discoloration of an azo dye, methyl orange (MO), by heterogeneous Fenton-like reaction using natural schorl as catalyst were investigated in this study. Among the three kinetic models (the first-order, the second-order, and the Behnajady-Modirshahla-Ghanbery (BMG)), the BMG kinetic model was the best one to describe MO discoloration at different reaction conditions, due to its highest determination coefficients. The BMG model parameter, 1/m, increased with initial hydrogen peroxide (H2O 2) concentration, and schorl dosage and reaction temperature increased while the pH solution decreased. The phenomenon indicated that the initial MO discoloration rate increased with the ascending of the initial H 2O2 concentration, schorl dosage, and reaction temperature and the descending of the pH solution. Meanwhile, another BMG parameter, 1/b, except for the one at pH=5, were all around 1, implying that the schorl-catalyzed Fenton-like reaction had high capacity for MO discoloration. The possible reason for these phenomena was interpreted from the point of view of OH generation and Fe dissolution. Generally speaking, the amount of hydroxyl radicals increased with initial H2O2 concentration, increased schorl dosage and reaction temperature, and decreased pH solution, playing an important role in the change of 1/m values. The concentration of soluble iron ions at all adopted experimental conditions ranged from 0.23 to 1.14 mg/L, much lower than the European Union directive (2 mg/L), which demonstrated that natural schorl would be a promising heterogeneous catalyst for the Fenton-like reaction. Finally, a possible mechanism for this process was put forward. © Springer Science+Business Media Dordrecht 2013.

Soil is one of the compartments most affected by the accumulation of pollutants from anthropic sources. The present study allowed the identification of the sensitivity of the Allium cepa test system to evaluate solubilized soils from two points in the area contaminated by heavy metals, as well as a point of reference. They are all located in the municipality of Triunfo, state of Rio Grande do Sul, Brazil. The parameters used for evaluation were germination index, mitotic index, chromosomal aberrations (CA), and index of mutagenicity index (IMUT) presented by A. cepa. Significant responses of CA were observed in the two samples of contaminated soil, but IMUT was significant only for soil 3. The toxicity and cytotoxicity indexes did not show significant responses. The results indicate that the A. cepa plant test system was sensitive to investigate the genotoxicity of the soil samples and can be used as an alert in studies on soil contamination. It was partially concordant with the mutagenic responses already detected for the Salmonella/microsome assay in previous studies.

The present study analyzes the acute and behavioral toxicity of two commercial formulations of endosulfan and atrazine (Gesaprim 90 WDG® and Zebra Ciagro®, respectively) on the cyclopoid copepod Mesocyclops longisetus. The studied behavior was the “escape ability” because of its ecological importance in natural predator–prey interactions. This was investigated using two experimental designs: (1) a simulated predator (applying a hydraulic device) and (2) a real one (the zooplanktophagous fish Cnesterodon decemmaculatus). Both pesticides resulted highly toxic to adults and nauplii at even relatively low concentrations and similar to those found in field studies. Copepods’ survival was not only directly affected but also indirectly through altering their escape behavior, which may have increased their vulnerability to predation. The escape ability, measured with the simulated predator was stimulated early (up to 6 h of exposition) but inhibited later (after 24 h of exposition). The predation experiments with the real predator were in accordance with these results. The comparison of both experimental designs corroborates the effectiveness of the hydraulic mechanism as a testing method.

The objectives of this study were to determine the acute toxicity of cadmium and to examine the bioaccumulation and elimination of cadmium in different tissues of the freshwater prawn Macrobrachium sintangese. It also evaluated the structural damage of gills and hepatopancreas of M. sintangese when administered to sublethal cadmium concentration and when exposed prawns were transferred to cadmium-free media. According to the mortality data, the 96 h LC₅₀ value of Cd to M. sintangese was 86 μg/L. The highest cadmium accumulation was observed in gills, followed by the hepatopancreas, and the abdominal muscle. After being transferred to cadmium-free media, the highest cadmium elimination was observed in abdominal muscle, followed by the gills and hepatopancreas. The gills of prawns exposed to cadmium exhibited a severe hyperplasia, vacuolization, and multiple necroses which resulted to the swelling of lamellae. After transferring the cadmium-exposed prawns into the control media, the histopathological effects decreased. Severe alterations to the hepatopancreatic tissue were observed in prawns exposed to cadmium. The tubular epithelial cells were heavily vacuolated and even ruptured. The number of large vacuoles and R cells appeared in the tubular epithelial cells of the hepatopancreas. After transferring to the control media, the histological alterations of the hepatopancreas decreased. The tubular epithelial cells began to rearrange to the normal structure. The number of R cells and B cells were noted in the epithelial cells. The thickness of tubular epithelial cells was comparable to the controls. Due to the sensitivity of M. sintangese to cadmium, therefore this species potentially can be used as a test organism in toxicity assays.

An electrokinetic technique was used to remediate As-, Cu-, and Pb-contaminated paddy soil in a real field on a pilot scale. A hexagonal electrode placement with one anode at the center and six cathodes at the vertices of the hexagon was installed in the field. After operation for 4 weeks, the average removal of Pb was 64.9 % in the top layer (0–0.4 m), 81.2 % in the middle layer (0.4–0.8 m), and 66.9 % in the bottom layer (0.8–1.2 m). The removal of As was 28.2 % in the top layer, 43.2 % in the middle layer, and 24.5 % in the bottom layer. The removal of Cu was 17.7 % in the middle layer and was not observed in the other layers. The relatively high removal of Pb might come from the more labile fraction of Pb in soil compared to As and Cu. However, the circulation of anolyte using an alkaline solution to enhance removal of As failed because the electrolyte leaked between the anode and surrounding soil. Effective circulation might enhance the performance of the electrokinetic process.

The aims of the present study were to identify the halophilic Archaea that can degrade aromatic hydrocarbons (namely, p-hydroxybenzoic acid, naphthalene, phenanthrene, and pyrene) and to determine their catabolic pathways in the process of degrading the hydrocarbons. It was determined nine archaeal isolates used p-hydroxybenzoic acid, naphthalene, phenanthrene, and pyrene as sole carbon and energy sources. The isolates were identified as Halobacterium piscisalsi, Halorubrum ezzemoulense, Halobacterium salinarium, Haloarcula hispanica, Haloferax sp., Halorubrum sp., and Haloarcula sp. by 16S rRNA gene sequences. Activity of catechol 1,2 dioxygenase and protocatechuate 3,4 dioxygenase enzyme of the ortho cleavage pathway were detected. Determination of the genes of these dioxygenases was also shown. This study clearly demonstrated for the first time that Halorubrum sp. and H. ezzemoulense among the isolates were able to grow at 20 % (w/v) NaCl, utilizing p-hydroxy-benzoic acid, naphthalene, phenanthrene, and pyrene as the sole carbon sources.

In this paper, the possible effect of surface ozone on soybean, wheat, rice, and maize crops in East Asia in 2000, 2005, and 2020 is estimated. Spatial distribution and temporal variation of surface ozone concentrations are simulated using the Models-3 Community Multiscale Air Quality Modeling System coupled with the Regional Emission Inventory in Asia (CMAQ/REAS). The effect of surface ozone on main crops in East Asia is evaluated based on accumulated exposure over a threshold of 40 ppb (AOT40 index) during a period of 3 months of the growing season. We demonstrate some of the implications for policy-making in air quality management for East Asia by highlighting the effect of elevated surface ozone concentrations on harvest losses and the corresponding value of the main crops. These concentrations are calculated based on three scenarios of emission reduction policies in 2020: policy success case (PSC), reference case (REF), and policy failure case (PFC). Assuming no future changes in land use or cropping patterns from 2000 to 2020, we find that the highest relative yield (RY) losses are in wheat and soybean in East Asia. The RY losses for wheat are estimated to range between 17 and 35 % in 2000, 21 and 49 % in 2005, 18 and 36 % in 2020 (PSC), 20 and 46 % in 2020 (REF), and 22 and 62 % in 2020 (PFC); the corresponding values for rice are 6 and 12 %, 6 and 17 %, 6 and 15 %, 6 and 17 %, and 7 and 20 %; for soybean, they are 12 and 16 %, 19 and 25 %, 18 and 33 %, 21 and 40 %, and 25 and 49 %; and for maize, they are 3 and 4 %, 5.7 and 6 %, 6 and 9 %, 9 and 11 %, and 12 and 14 %. Quantitatively, the estimated losses in production of wheat in East Asia in 2000, 2005, and 2020 (PSC, REF, and PFC scenarios) are 32.4, 44.3, 42.2, 54.0, and 72.3 t, respectively; for rice, 34.9, 39.4, 42.4, 46.5, and 54.6 mmt; for soybean, 1.9, 3.3, 3.6, 4.9, and 7.0 mmt; and for maize, 3.6, 8.1, 11.4, 15.4, and 21.5 mmt. The estimated values of crop losses in East Asia in 2000, 2005, and 2020 (PSC, REF, and PFC scenarios) are as follows: 13.8, 17.4, 18.2, 21.3, and 26.7 billion Int. $. Therefore, adaptation measures in the PSC scenario in contrast to the PFC scenario could save around 8.5 billion Int. $ across East Asian countries in 2020.