Unexpected behavior of Zn,Cd, Cu,and Pb in soils contaminated by ore processing after 70 years of burial

Environmental Chemistry Letters - Heavy metals in contaminated ore processing areas present a risk of contamination of waters and life. Therefore, the most mobile fractions of metals, which can be...     

Striking the balance: Challenges and perspectives for the protected areas network in northeastern European Russia

Increasing anthropogenic pressure on the largest remaining tracts of old-growth boreal forest in Europe necessitates additional conservation of ecosystems and biodiversity in northeastern European Russia. In a regional network comprising 8 % of the Nenets Autonomous District and 13.5 % of the Komi Republic, 248 areas have varying protected statuses as state nature reserves (zapovedniks), national parks, reserves/sanctuaries (zakazniks), or natural monuments. Due to increased natural resource extraction in this relatively pristine area, designation of additional protected areas is critical for the protection of key ecological sites. The history of ecological preservation in these regions is herein described, and recent recommendations for incorporating additional ecologically representative areas into the regional network are presented. If the protected area network can be expanded, the overall environmental stability in these globally significant ecosystems may remain intact, and can help Russia meet the 2020 Aichi conservation targets, as set forth by the Convention of Biological Diversity.     

Corrected first-order model of DEHP degradation

Corrected first-order model was applied to describe the biological removal of di-(2-ethylhexyl) phthalate (DEHP) in sludge-amended soil along with batch and continuous-flow anaerobic reactors with different initial/influent DEHP concentrations and hydraulic retention times. Only two kinetic parameters - the first-order rate coefficient k describing the overall kinetics of the process and the coefficient alpha characterizing the fraction of non-degradable DEHP - were used to fit the array of experimental data published earlier. The values of k and alpha estimated for DEHP removal from different sludges at 35 degrees C varied within the range of 0.03-0.07 d(-1) and 0.25-0.5, respectively. In sludge-amended soil, the first-order kinetic coefficient k increased from 0.007 to 0.028 d(-1) and the fraction of non-degradable DEHP alpha decreased from 0.6 to 0.5 with the increase in incubation temperature from 5 to 20 degrees C. The rate coefficient k increased by a factor of 2 when the temperature increased from 5 to 10 degrees C or from 10 to 20 degrees C.     

Assessment of elemental composition and properties of copper smelter-affected dust and its nano- and micron size fractions

A comprehensive approach has been developed to the assessment of composition and properties of atmospherically deposited dust in the area affected by a copper smelter. The approach is based on the analysis of initial dust samples, dynamic leaching of water soluble fractions in a rotating coiled column (RCC) followed by the determination of recovered elements and characterization of size, morphology and elemental composition of nano-, submicron, and micron par ticles of dust separated using field-flow fractionation in a RCC. Three separated size fractions of dust (<0.2, 0.2–2, and >2 μm) were characterized by static light scattering and scanning electron microscopy, whereupon the fractions were analyzed by ICP-AES and ICP-MS (after digestion). It has been evaluated that toxic elements, which are characteristics for copper smelter emissions (As, Cu, Zn), are accumulated in fraction >2 μm. At the same time, up to 2.4, 3.1, 8.2, 6.7 g/kg of As, Cu, Zn, Pb, correspondently, were found in nanoparticles (<0.2 μm). It has been also shown that some trace elements (Sn, Sb, Ag, Bi, and Tl) are accumulated in fraction <0.2, and their content in this fraction may be one order of magnitude higher than that in the fraction >2 μm, or the bulk sample. It may be assumed that Sn, Sb, Ag, Bi, Tl compounds are adsorbed onto the finest dust particles as compared to As, Cu, Zn compounds, which are directly emitted from the copper smelter as microparticles.

     

Shell-boring versus tube-dwelling: is the mode of life fixed or flexible? Two cases in spionid polychaetes (Annelida, Spionidae)

Free crawling was an original life style, and the ability to build tubes and bore into shells evolved independently in various annelids and more than once within the family Spionidae. Absence of morphological differences between the shell-boring (SB) and tube-dwelling (TD) spionid worms and the innate ability of borers to build tubes raised a question whether the mode of life is fixed or flexible. Sequence data of three gene fragments of the mitochondrial 16S rDNA and nuclear 18S and 28S rDNA (in total 1,677 bp) have shown that SB and TD individuals of Dipolydora carunculata from the Sea of Japan were genetically identical, whereas those of Polydora triglanda from Taiwan were genetically distant and not conspecific. These data indicate that some species are constrained to a certain mode of life, while others are flexible and individuals can be either SB or TD depending on the place of settlement in the end of their larval development.     

Seasonal nitrogen fluxes of the Lena River Delta

The Arctic is nutrient limited, particularly by nitrogen, and is impacted by anthropogenic global warming which occurs approximately twice as fast compared to the global average. Arctic warming intensifies thawing of permafrost-affected soils releasing their large organic nitrogen reservoir. This organic nitrogen reaches hydrological systems, is remineralized to reactive inorganic nitrogen, and is transported to the Arctic Ocean via large rivers. We estimate the load of nitrogen supplied from terrestrial sources into the Arctic Ocean by sampling in the Lena River and its Delta. We took water samples along one of the major deltaic channels in winter and summer in 2019 and sampling station in the central delta over a one-year cycle. Additionally, we investigate the potential release of reactive nitrogen, including nitrous oxide from soils in the Delta. We found that the Lena transported nitrogen as dissolved organic nitrogen to the coastal Arctic Ocean and that eroded soils are sources of reactive inorganic nitrogen such as ammonium and nitrate. The Lena and the Deltaic region apparently are considerable sources of nitrogen to nearshore coastal zone. The potential higher availability of inorganic nitrogen might be a source to enhance nitrous oxide emissions from terrestrial and aquatic sources to the atmosphere.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01665-0.     

Radioactive isotopes in atmospheric aerosols over Russia and the Sea of Japan following nuclear accident at Fukushima Nr. 1 Daiichi Nuclear Power Station in March 2011

Artificial radionuclides, such as iodine-131 (¹³¹I), cesium-134 (¹³⁴Cs), and cesium-137 (¹³⁷Cs), as well as natural isotopes of beryllium-7 (⁷Be) and potassium-40 (⁴⁰K) have been registered in atmospheric aerosols over Vladivostok selected from 11 March to 17 June 2011. Additionally, ¹³⁴Cs and ¹³⁷Cs were detected in atmospheric aerosols over Tomsk selected from 16 March to 17 June 2011. Artificial radionuclides were also discovered in atmospheric wet depositions sampled in Vladivostok from 3 to 17 May 2011. Moreover, these radionuclides have been registered in atmospheric aerosols over the sea surface of the Sea of Japan selected from 3 to 31 May 2011 during an expedition of the “Nadezhda” sailing ship. From 18 March to 15 April, an increase in concentrations of atmospheric aerosols over Vladivostok from 108.8 to 321.5 μg/m³ has been registered. It was accompanied by increased activity concentrations of ¹³⁴Cs, ¹³⁷Cs, and the ¹³¹I. During the period from 18 March to 15 April, activity concentrations of ¹³⁷Cs and ¹³⁴Cs in atmospheric aerosols increased 100 times compared with the minimum detectable concentration (MDC) level and peaked in the weekly sample gathered from 8 to 15 April (145.0 and 105.3 μBq/m³, respectively). Variability of concentrations of natural isotopes of ⁷Be and ⁴⁰K was not greater than 1 order of magnitude throughout the sampling period. Maximal values of ¹³⁷Cs and ¹³⁴Cs concentrations (1,281.5?±?141 and 384.4?±?42.3 μBq/m³, respectively) in Tomsk were reached in samples taken from 1 to 2 April. For the atmospheric aerosol samples from the Sea of Japan, the largest concentration of ¹³¹I (392.3?±?215.7 μBq/m³) was detected from 13 to 19 May, while all other samples had much lower concentration values. Synoptic analysis of back trajectories movement of air masses showed that the radioactive cloud came to Vladivostok from the regions of Siberia and northeastern part of China. Synoptic analysis for Tomsk showed that during the period of maximal activity concentrations (1–9 April), air masses were arriving from the European part of Russia and north of Kazakhstan.     

Destruction of EDTA using Ce(IV) mediated electrochemical oxidation: a simple modeling study and experimental verification

Mediated electrochemical oxidation (MEO) is a recent development in the environmental research field for the complete destruction of organic pollutants. This study presents the destruction of EDTA by cerium(IV) MEO process in nitric acid medium. The destruction reaction was carried out in a continuous stirred tank reactor under various conditions. A simple kinetic model was developed to analyze and simulate the organic destruction in the MEO process. The model was based on the calculation of the total mass balance, the component mass balance, and the energy balance in the reactor and also in the heating jacket. The sensitivity to key operating conditions such as the initial EDTA concentration (50-200 mM), EDTA feeding time (30-180 min), reaction temperature (323-363 K), and the rate laws corresponding to zero-, first-, second-, and third-order reaction were analyzed. It was found that the model simulated agreed well with the experimental data for EDTA oxidation. The results obtained showed the suitability of the MEO process for the effective mineralization of high concentrations of EDTA.     

Simulating transport of 129I and idealized tracers in the northern North Atlantic Ocean

Transport of the radioactive tracer Iodine-129 (¹²⁹I, T _1/2 = 15.7 Myr) in the northern North Atlantic Ocean has been investigated using a global isopycnic Ocean General Circulation Model (OGCM) and observed data. ¹²⁹I originates mainly from the nuclear fuel reprocessing plants in Sellafield (UK) and La Hague (France), and is transported northwards along the Norwegian coast, and then into surface and intermediate layers in the Arctic Ocean through the Barents Sea and the Fram Strait, but also partly recirculating south along the eastern coast of Greenland. In the North Atlantic Subpolar Seas, ¹²⁹I is mainly found in dense overflow waters from the Nordic Seas being exported southwards in the Deep Western Boundary Current, and to a lesser extent in surface and intermediate layers circulating cyclonically within the Subpolar Gyre. Observed concentration of ¹²⁹I along a surface transect in the eastern Nordic Seas in 2001 is captured by the OGCM, while in the Nansen Basin of the Arctic Ocean the OGCM overestimates the observed values by a factor of two. The vertical profile of ¹²⁹I in the Labrador Sea, repeatedly observed since 1997 to present, is fairly realistically reproduced by the OGCM. This indicates that the applied model system has potential for predicting the magnitude and depth of overflow waters from the Nordic Seas into the North Atlantic Subpolar Seas. To supplement the information obtained from the ¹²⁹I distribution, we have conducted a number of idealized tracer experiments with the OGCM, including tracers mimicking pure water masses, and instantaneous pulse releases. New insight into time-scales of tracer transport in this region is obtained by utilizing a few recently developed methods based on the theory of Transit Time Distribution (TTD) and age of tracers. Implications for other types of “anomalies” in the northern North Atlantic Ocean, being anomalous hydrography or chemical tracers, and how they are interpreted, are discussed.