Streptomyces sp. MC1, previously isolated from sugar cane, has shown ability to reduce Cr(VI) in liquid minimal medium and soil samples. The objective of this work was to demonstrate the intracellular chromium accumulation by Streptomyces sp. MC1 under different culture conditions. This strain was able to accumulate up to 3.54 mg of Cr(III) per gram of wet biomass, reducing the 98% of Cr(VI) and removing 13.9% of chromium from the culture medium supernatants. Streptomyces sp. MC1 chromium bioaccumulation ability was corroborated by using Timm's reagent technique, a low-cost method, which has been used by first time to detect chromium deposits in bacteria. The results of atomic absorption spectrometry, scanning electron microscopy, and energy dispersive X-ray analysis suggest that the mechanism of Cr(VI) resistance observed in Streptomyces sp. MC1 includes adsorption coupled with reduction to Cr(III), and finally, Cr(III) bioaccumulation. This mechanism have special relevance to remediation of Cr(VI) contaminated environments by Streptomyces sp. MC1.

The aim of the present work was to determine peculiarities of accumulation of ionic state 137Cs in model experiments with seedlings of spring wheat (Triticum aestivum L., “Nandu”) using laboratory experiments and to evaluate the complex effect of 137Cs ionizing radiation and geochemical factors on the growth of this plant. 137Cs accumulation in seedlings is influenced by the presence of mineral substances in the nutritional medium and by the conditions of illumination. Mineral substances (K+, Ca2+, Mg2+, Cu2+, NH4 +, P5+, Fe3+) reduced the 137Cs accumulation coefficient of seedlings approximately three times. Addition of heavy metals as well as anionic group NO3 − to the growth medium caused insignificant changes in the level of radionuclide accumulation. In the model systems of RNA synthesis with wheat seedling cells nuclei isolated after complex treatment (in vivo) by 137Cs and HM showed clear inhibition of the RNA-polymerase II. This inhibition manifested itself as a complex effect of 137Cs ionizing radiation and heavy metals.

This work deals with the topic of qualification and prioritization of environmental impact in abandoned mining sites using fuzzy logic. It aims to classify old mining sites and describe their environmental impact through a numeric index. This is variable in the interval [0,1], and was named as index of environmental impact (I EI). Its determination was made through a fuzzy inference system that allows the integration of several characterization components. The system was supported by data obtained in five sites in NW Portugal, which is a paradigmatic region regarding the variety of typical environmental problems provoked by old metallic mines. These sites may be considered environmental patterns as they represent such regional diversity. In a general way, the I EI can be applied to other sites where the existence of abandoned mining structures generates environmental impact.

To evaluate the potential public health impact of exposure to airborne particulate matter, concentrations of PM10 and PM2.5 were measured at 16 monitoring stations in Pearl River Delta. Epidemiological studies were collected, and meta-analysis method was used to get the exposure-response functions for health effects on mortality of residents in China. Chinese studies reported somewhat lower exposure-response coefficients as compared with studies abroad. Both Poisson model and life-table approach were used to estimate the health effects including acute effects and chronic effects. For short-term exposure, 2,700 (95% confidence interval (CI), 2,200–3,400) premature deaths would be prevented annually if PM10 daily concentrations reduced to below World Health Organization (WHO) guideline value. Much more benefits would be gained for long-term exposure. The annual avoidable deaths would be 42,000 (95% CI, 28,000–55,000) and 40,000 (95% CI, 23,000–54,000) for PM10 and PM2.5, respectively, if the particulate matter annual concentrations were reduced to below WHO guideline values. And the average lifespan of residents would prolong 2.57 years for PM10 and 2.38 years for PM2.5 if reducing the PM annual concentrations. The benefits varied greatly in different areas and different manage strategies should be carried out to protect human health effectively.

The aim if this study was to assess the distribution of mercury in water, suspended particulate matter, surface sediments and biota from the Sado estuary, which, for the most part, is classified as a natural reserve, so as to evaluate its environmental quality status in terms of mercury contamination. Besides the diffuse sources of mercury coming into the Sado estuary, there are also additional contributions from the northern industrial zone and from the urban areas within the system. Applying national and international guidelines to different environmental matrices, the results obtained show that the system does not seem to be under environmental risk as far as mercury contamination is concerned. These quality guidelines can be used to rank and prioritise sites of concern. Hence, the area at the northern industrialised area deserves particular attention. The concentration of mercury in sediments of this area (0.54 mg kg⁻¹) simultaneously succeeded the European Union Water Framework Directive (EU-WFD) reference value, the OSPAR Convention Ecotoxicological Assessment Criteria (EACs) and is classified as class 2 in degree of contamination by the National legislation, which implies some legal restrictive rules. Considering the stations close to urbanised areas, one exceeded the OSPAR EACs for dissolved mercury, whilst the other exceeded the EU-WFD reference value for mercury concentrations in sediments. No statistical significant relations were found between mercury concentrations in biota (Ulva sp, Hediste diversicolor, Scrobicularia plana, Cerstoderma edule and Carcinus maenas) and in the abiotic matrices (sediment and water column, including mercury in its dissolved form and associated to suspended particulate matter). This paper provides an overview of the guidelines for Hg proposed for a considerable number of coastal systems of the northern hemisphere and highlights the complex interactions of Hg in the different environmental compartments in low contaminated systems.

The availability of metals to plants is a complex function of numerous environmental factors. Many of these factors are interrelated, and vary seasonally and temporally. The current study intended to understand the influence of seasonal fluctuations and the vegetation of salt marsh plants (SMPs; Halimione portulacoides, Juncus maritimus) on sediment’s mercury (Hg) and its pH and redox potential (Eh), as well as their cumulative effect on the plant’s Hg-accumulation and Hg-partitioning potential. The area selected for the study was Laranjo Basin at Ria de Aveiro lagoon (Portugal) where a known Hg gradient was existed due to chlor-alkali plant discharge. Three sampling sites (L1, L2 and L3) were selected along a transect defined by the distance from the main Hg source. Samples were also collected from the Hg-free site (R). Irrespective of the plant vegetation, Hg in sediments gradually increased with a decreasing distance towards Hg-point source. The sediment colonised by J. maritimus showed more Hg concentration compared with H. portulacoides irrespective of the season. As a whole, J. maritimus accumulated Hg more than H. portulacoides at all the sampling sites, whereas in root, stem and leaf, the concentration was ranked as: L1 > L2 > L3 in both the plant species and was differentially influenced by seasonal changes. Moreover, root of both plants exhibited highest Hg concentration compared with stem and leaf. In addition, the leaf of H. portulacoides exhibited more Hg than leaves of J. maritimus. Bioaccumulation and translocation factors and dry weight were differentially influenced by seasonal changes. Taking together the results, the physico-chemical properties of sediment especially the sediment-Eh seems to be influnced by the type of plant vegetation and seasonal changes which in turn may have influenced the chemistry of sediments; thus, it enfluences the bioavalability of Hg and the Hg-retention capacity of both salt marsh sediments (SMSs) and SMPs (bioaccumulation factor). Moreover, SMSs vegetated by J. maritimus exhibited a stronger capacity for the retention and phytostabilization of Hg belowground (in sediments and/or roots) than those dominated by H. portulacoides. Conversely, those SMSs extensively vegetated by H. portulacoides are expected to translocate more Hg to aboveground parts, acting as a potential source of this metal to the marsh ecosystem. Therefore, J. maritimus and H. portulacoides may be used repectively for phytostabilization (in rhizosediments) and phytoextraction (by accumulation in aboveground plant tissue for subsequent plant removal).

Since the 1950s, large areas of upland peat have been afforested in northern European countries. Due to the poor phosphorus (P) adsorption capacity and low hydraulic permeability in blanket peat soil and increased labile P sources, harvesting these blanket peat forests can significantly increase P concentrations in the receiving aquatic systems. This paper briefly reviews the current management practices on the control of P releases from forestry in Ireland and the UK, and proposes a possible novel practice—grass seeding clearfelled areas immediately after harvesting, which should reduce P release from blanket peat forest harvesting. The study was conducted in the Burrishoole Catchment in the west of Ireland. A field trial was carried out to identify the successful native grass species that could grow quickly in the blanket peat forest. The two successful grass species—Holcus lanatus and Agrostis capillaris—were sown in three blanket peat forest study plots with areas of 100, 360, and 660 m2 immediately after harvesting. Areas without grass seeding were used as controls. One year later, the P content in the aboveground vegetation biomass of the three study plots were 2.83, 0.65, and 3.07 kg P ha−1, respectively, which were significantly higher than the value of 0.02 kg P ha−1 in the control areas. The water extractable phosphorus in the three study plots were 8.44, 9.83, and 6.04 mg (kg dry soil)−1, respectively, which were lower than the value of 25.72 mg (kg dry soil)−1 in the control sites. The results indicate that grass seeding of the peatland immediately after harvesting can quickly immobilize significant amounts of P and warrants additional research as a new Best Management Practice following harvesting in the blanket peatland forest to mitigate P release.

We investigated sediments from 23 lakes situated in northeastern Poland and analyzed them for major constituents and selected heavy metals. Short sediment cores were collected from the deepest parts of the lakes, and subsequently, a surface layer (0–2 cm) and reference layer (50–52 cm) were sampled from each. In the collected samples, the content of the major constituents (organic matter, carbonates, and minerogenic material) and chosen heavy metals (Cd, Cu, Ni, Pb, and Zn) was analyzed. In the reference layer, representing natural metal content, we identified quite a substantial diversity among lakes, making it difficult to pinpoint one geochemical background value for the whole region. A multivariate analysis of the interrelationships among elements and a comparison of the median values revealed no statistically significant differences between surface and reference levels. The ratio of the mean content in the surface and reference sediments ranged from 0.9 to 1.6, indicating the lack of or only slight anthropogenic pollution in surface sediments. From a spatial perspective, higher metal contents were observed in the eastern part of the study area, but this trend manifested in both surface and reference sediments. Thus, the inference is that the recently accumulated sediments are characterized by a content that is representative of the natural geochemical background for the selected metals.

In the last 10 years, the number of field applications of zero-valent iron differing from permeable reactive barrier has grown rapidly and at present are 112. This study analyzes and compares such field applications. By using statistical analysis, especially ANOVA and principal component analysis, this study shows that chlorinated solvent contamination can be treated efficiently by using zero-valent iron material singly or associated with other technologies. In the analyzed sample of case studies, the association with microbial dechlorination increased significantly the performances of nanoscale iron. This is likely due to the synergistic effect between the two processes. Millimetric iron was always used in association with source zone containment; therefore, it is not possible to distinguish the contributions of the two techniques. The comparison also shows that catalyst addition seems to not dramatically improve treatment efficiency and that such improvement is not statistically significant. Finally, the injection technology is correlated to the type of iron and to the soil permeability.