Influence of macroalgal diversity on accumulation of radionuclides and heavy metals in Bulgarian Black Sea ecosystems

Radionuclides and heavy metals were studied in green, brown and red Black Sea macroalgae by low-level gamma spectrometry and atomic absorption spectrometry. The samples were collected along the whole Bulgarian coast from 1996 to 2004. The levels have been depending on algae species, locations and year of sampling. The highest ¹³⁷Cs levels were found in red Ceramium rubrum species from all studied locations, while ²²⁶Ra and ²¹⁰Pb were up to three orders of magnitude higher in Bryopsis plumosa. The data showed that the red algae species (Rhodophyta) accumulate more heavy metals than the other phyla (except for Fe whose values were higher in green algae). The data confirmed that algae are valuable indicators of the environmental contamination. The observed elevated levels were mainly due to Danube, Dnieper and Dnester inputs in the NW corner of the Black Sea.     

Changes in the structure of chortobiont invertebrate community exposed to emissions from a copper smelter

The aboveground phytomass of meadow plants and the density of chortobiont invertebrates in secondary upland meadows were estimated using a biocenometer in three areas differing in the level of pollution with emissions from the Middle Ural Copper Smelter (Revda, Sverdlovsk oblast) in 2006 and 2007. As the smelter is approached, the total amount of phytomass (dry weight) decreases by a factor of 1.3–1.9, with the proportion of grasses reaching 100%; the total abundance of invertebrates increases two-to threefold due to sucking phytophages, which account for up to 80% of the invertebrate community. The abundance of gnawing phytophages near the smelter is reduced, with some taxa entirely missing (e.g., mollusks and phalangiid harvestmen). Rearrangements in chortobiont community structure are attributable to changes in the physiological state of plants and in the species diversity and architecture of the herbaceous layer, with consequent modification of hydrothermal conditions in it, as well as by the direct toxic effect of heavy metals.     

Interactions of Trametes versicolor, Coriolopsis rigida and the arbuscular mycorrhizal fungus Glomus deserticola on the copper tolerance of Eucalyptus globulus

The presence of high levels of Cu in soil decreases the shoot and root dry weights of Eucalyptus globulus. However, higher plant tolerance of Cu has been observed in the presence of the arbuscular mycorrhizal (AM) fungus Glomus deserticola. The hyphal length of G. deserticola was sensitive to low Cu concentrations, and the percentage of AM root colonisation and the metabolic activity of the AM fungus were also decreased by Cu. Therefore, a direct effect of Cu on the development of the AM fungus inside and outside the root cannot be ruled out. E. globulus colonised by G. deserticola had higher metal concentrations in the roots and shoots than do non-mycorrhizal plants; however, the absence of a higher root to shoot metal ratio in the mycorrhizal plants (1.70 ± 0.11) indicated that G. deserticola did not play a filtering/sequestering role against Cu. The saprobe fungi Coriolopsis rigida and Trametes versicolor were able to remove Cu ions from the asparagine–glucose growth media. However, plants inoculated with C. rigida and T. versicolor did not accumulate more Cu than non-inoculated controls, and the growth of the plant was not increased in the presence of these fungi. However, C. rigida increased the shoot dry weight, AM root length colonisation, and metabolic mycelial activity of plants colonised with G. deserticola in the presence of Cu; only this saprobe-AM fungus combination increased the tolerance of E. globulus to Cu. Inoculation with G. deserticola and C. rigida increased the E. globulus Cu uptake to levels reached by hyperaccumulative plants.     

Biosorption of Cu and Zn from aqueous solutions by dried marine green macroalga Chaetomorpha linum

The biosorption of the heavy metals Cu²⁺ and Zn²⁺ by dried marine green macroalga (Chaetomorpha linum) was investigated. The biosorption capacities of the dried alga for copper and zinc were studied at different solution pH values (2–6), different algal particle sizes (100–800 μm) and different initial metal solution concentrations (0.5–10 mM). An optimum pH value of 5 was found suitable for both metal ions biosorption for both metal ions. At the optimum particle size (100–315 μm), biosorbent dosage (20 g/l) and initial solution pH (pH 5), the dried alga produced maximum copper and zinc uptakes values (q_max) of 1.46 and 1.97 mmol/g respectively (according to the Langmuir model). The kinetic data obtained at different initial metal concentrations indicated that the biosorption rate was fast and most of the process was completed within 120 min. This study illustrated an alternative technique for the management of unwanted biological materials using processed algal material. C. linum is one of the fast-growing marine algae in the lake of Tunis and could be utilized as a biosorbent for the treatment of Cu²⁺ and Zn²⁺ contaminated wastewater streams.     

Information, power and environmental justice in Botany: the role of community information systems

In the environmental conflict that surrounds the sighting of hazardous waste facilities there is usually a volatile mix of disparities in power, expertise and information access as well as differing views on risk, which are all played out amidst commercial arrangements and environmental justice concerns. In recent times, the volatility of this mix has been further compounded by the growing climate of public concern and distrust surrounding scientific developments and technology. While there is no 'quick fix' to the complex conflict that this entails, community information systems (CISs) based on participatory models can help address the outstanding issues of capacity, information access, power inequities and environmental justice. CISs are an effective response to the five crucial elements of a toxic dispute, that is, the dialogue, capacity building, information access, evaluation of hazards and risk, and expertise. This paper will review the role of community accessible information systems in the dispute in Botany over the management and destruction of Orica Australia's stockpile of the persistent organic pollutant, hexachlorobenzene (HCB). It will focus on the role of CIS in responding to the challenges for expert information delivery, and in addressing the disparity of informational power within the toxic dispute.     

Copper and zinc bioavailabilities to ryegrass (Lolium perenne L.) and subterranean clover (Trifolium subterraneum L.) grown in biosolid treated Chilean soils

The purpose of this study was assessing Cu and Zn availabilities in soils amended with a biosolid through the determination of their sequentially extracted chemical forms and their relationship with the contents of these metals in ryegrass (Lolium perenne L.) and subterranean clover (Trifolium subterraneum L.) plant tissues cultivated in a greenhouse using four soils classified as Aquic Xerochrepts and Ultic Haploxeralfs representatives of potential areas for biosolids application in the central zone of Chile. The soils were treated with sewage sludge at a rate of 0 and 30 Mg ha⁻¹. The greenhouse experiment was carried out through a completely randomized block design in a 2 × 4 (biosolid rate × soil) arrangement, considering three repetitions per treatment. The soils used in the greenhouse experiment before and after cultivation, were sequentially extracted with specific reagents and conditions in order to obtain the following fractions: exchangeable, sodium acetate-soluble, soluble in moderately reducing condition, K₄P₂O₇-soluble, soluble in reducing condition, and soluble in strongly acid and oxidizing condition. It was established that Cu and Zn were predominantly found in soils in less available forms, associated to organic matter, oxides and clay minerals. Zinc concentration in ryegrass plants was higher than that found in subterranean clover plants in biosolid-amended soils. Zinc contents in ryegrass shoot and root correlated with the exchangeable, bound-to-carbonate, and bound-to-FeOx metal forms in control soil. Copper and Zn bioavailabilities were estimated through satisfactorily fitted multiple linear regression models, with determination coefficients from 0.77 to 0.99, which showed a positive contribution of the labile metal forms in soils, especially in relation to Zn in both plant species.     

太原地区公路旁土壤中重金属形态分布和生物有效性研究

采用盆栽试验结合形态分析技术研究了太原地区公路旁污染土壤中Pb,Cd,Cu和Zn的形态分布及其生物有效性。研究结果显示:除Cd外,残渣态是主要形态,可交换态的含量很少;土壤中Cd的碳酸盐结合态、可交换态含量较高,残渣态的含量很少;菜园土重金属的生物可利用性和迁移能力的顺序均是Cd>Cu>Zn>Pb,而高粱土的顺序是Cd>Zn>Cu>Pb,菜园土重金属的生物活性和迁移性较高粱土的大。农作物对Cd,Cu和Zn的累积能力远远大于对Pb的累积能力,且Cd,Cu和Zn向地上部转移的速度也明显比Pb快。研究成果将为评估污染土壤中重金属的危害提供科学依据。     

经过水泥固化的重金属废物的穿透渗漏实验

采用穿透渗漏实验方法研究了经水泥固化的重金属废物的长期渗漏行为。用由Ｐｂ＾２＋、Ｚｎ＾２＋、Ｃｕ＾２＋、Ｎｉ＾２＋和Ｃｒ＾６＋５种重金属组成的合成废物样品进行２组实验。实验研究了渗漏实验液流速、ＰＨ的变化和金属渗漏能力对固体废物长期渗漏行为的影响。     

Comparison of sediment metal:aluminum relationships between the eastern and gulf coasts of the United States

Aluminum is often used as a conservative tracer toseparate natural from anthropogenic components ofmetal contamination in marine sediments, butidentifying uncontaminated sites to develop baselinemetal:aluminum relationships can be problematic inpopulated areas. Here we present a new method foridentifying baseline relationships in high populationdensity areas. The method involves comparing theresidual from the metal:aluminum regression with anindependent estimate of laboratory measurement error,based on the premise that mean square error from theregression must equal laboratory measurement error forany data set that is free of anthropogenicallyenriched sites. The method is applied to data setsfrom the mid-Atlantic and Gulf coasts of the UnitedStates to test consistency in baseline relationshipsbetween these two coasts of geologically differentorigin. Differences in metal:aluminum relationshipsbetween coasts were found to be small and limited tothe least abundant trace metals.