Atmospheric versus biological sources of polycyclic aromatic hydrocarbons (PAHs) in a tropical rain forest environment

To distinguish between pyrogenic and biological sources of PAHs in a tropical rain forest near Manaus, Brazil, we determined the concentrations of 21 PAHs in leaves, bark, twigs, and stem wood of forest trees, dead wood, mineral topsoil, litter layer, air, and Nasutitermes termite nest compartments. Naphthalene (NAPH) was the most abundant PAH with concentrations of 35 ng m(-3) in air (>85% of the sum of 21PAHs concentration), up to 1000 microg kg(-1) in plants (>90%), 477 microg kg(-1) in litter (>90%), 32 microg kg(-1) in topsoil (>90%), and 160 microg kg(-1) (>55%) in termite nests. In plants, the concentrations of PAHs in general decreased in the order leaves > bark > twigs > stem wood. The concentrations of most low-molecular weight PAHs in leaves and bark were near equilibrium with air, but those of NAPH were up to 50 times higher. Thus, the atmosphere seemed to be the major source of all PAHs in plants except for NAPH. Additionally, phenanthrene (PHEN) had elevated concentrations in bark and twigs of Vismia cayennensis trees (12-60 microg kg(-1)), which might have produced PHEN. In the mineral soil, perylene (PERY) was more abundant than in the litter layer, probably because of in situ biological production. Nasutitermes nests had the highest concentrations of most PAHs in exterior compartments (on average 8 and 15 microg kg(-1) compared to <3 microg kg(-1) in interior parts) and high PERY concentrations in all compartments (12-86 microg kg(-1)), indicating an in situ production of PERY in the nests. Our results demonstrate that the deposition of pyrolytic PAHs from the atmosphere controls the concentrations of most PAHs. However, the occurrence of NAPH, PHEN, and PERY in plants, termite nests, and soils at elevated concentrations supports the assumption of their biological origin.     

Avoidance behaviour of Enchytraeus albidus: effects of benomyl, carbendazim, phenmedipham and different soil types

Enchytraeids are typical inhabitants of many soils, contributing to vital processes of this environmental compartment. Indirectly they are involved in regulating the degradation of organic matter, as well as improving the pore structure of the soil. Due to their behaviour, they are able to avoid unfavourable environmental conditions. Avoidance tests with enchytraeids, initially developed with earthworms by several authors, are quick and easy to perform. With these tests a first assessment of the toxicity of a (contaminated or spiked) soil is possible in just 48 h by using the reaction of the enchytraeids as measurement endpoint. In this period of time the organisms can choose between the control soil and the other soil (a contaminated or spiked or another soil with different physico-chemical properties). In the tests reported here, the enchytraeids were exposed to control soils spiked with the fungicides Benomyl and Carbendazim and the herbicide Phenmedipham. Several chemical concentrations were tested in order to evaluate the avoidance behaviour to toxic substances. In fact, often these short-term screening tests gave results showing avoidance at concentrations in a range similar to the acute test results but, higher than in chronic tests. Further tests are needed to decide whether the results gained in this study can be extrapolated to other chemicals. It is proposed to standardize the Enchytraeid Avoidance Test as it is currently done for the Earthworm Avoidance Test by the International Standard Organization (ISO).     

An integrated assessment of estrogenic contamination and biological effects in the aquatic environment of The Netherlands

An extensive study was carried out in the Netherlands on the occurrence of a number of estrogenic compounds in surface water, sediment, biota, wastewater, rainwater and on the associated effects in fish. Compounds investigated included natural and synthetic hormones, phthalates, alkylphenol(ethoxylate)s and bisphenol-A. The results showed that almost all selected (xeno-)estrogens were present at low concentrations in the aquatic environment. Locally, they were found at higher levels. Hormones and nonylphenol(ethoxylate)s were present in concentrations that are reportedly high enough to cause estrogenic effects in fish. Field surveys did not disclose significant estrogenic effects in male flounder (Platichthys flesus) in the open sea and in Dutch estuaries. Minor to moderate estrogenic effects were observed in bream (Abramis brama) in major inland surface waters such as lowland rivers and a harbor area. The prevalence of feminizing effects in male fish is largest in small regional surface waters that are strongly influenced by sources of potential hormone-disrupting compounds. High concentrations of plasma vitellogenin and an increased prevalence of ovotestes occurred in wild male bream in a small river receiving a considerable load of effluent from a large sewage treatment plant. After employing in vitro and in vivo bioassays, both in situ and in the laboratory, we conclude that in this case hormones (especially 17 alpha-ethynylestradiol) and possibly also nonylphenol(ethoxylate)s are primarily responsible for these effects.     

Growth of Azotobacter chroococcum in chemically defined media containing p-hydroxybenzoic acid and protocatechuic acid

Growth and utilization of different phenolic acids present in olive mill wastewater (OMW) by Azotobacter chroococcum were studied in chemically defined media. Growth and utilization of phenolic acids were only detected when the microorganism was cultured on p-hydroxybenzoic acid at concentration from 0.01% to 0.5% (w/v) and protocatechuic acid at concentration from 0.01% to 0.3% (w/v) as sole carbon sources suggesting that only these phenolic compounds could be utilized as a carbon source by A. chroococcum. Moreover when culture media were added with a mixture of 0.3% of protocatechuic acid and 0.3% p-hydroxybenzoic acid, the microorganism degradated in first place protocatechuic acid and once the culture medium was depleted of this compound, the degradation of p-hydroxybenzoic acid commenced very fast.     

Distribution and partitioning of phosphorus in solid waste and sediments from drainage canals in the industrial belt of Delhi, India

Phosphorus is an essential and often limiting nutrient in both marine and freshwater ecosystems. However, its oversupply is of great concern in many environments due to its role in eutrophication. The concentration and distribution of sediment bound phosphorus species not only record its input into the environment, but also suggest their possible sources. It is recognized that the features of phosphorus behaviour have not been extensively studied in urban environments. In this study, phosphorus in solid waste and sediments from drainage canals within the industrial belt of Delhi were fractionated into five operationally defined forms, i.e., exchangeable or loosely sorbed phosphorus (Exch-P), Fe-bound phosphorus (Fe-P), authigenic apatite, CaCO3-bound phosphorus and biogenic apatite (Acet-P), detrital apatite (Det-P) and organic-bound phosphorus (Org-P), in order to assess the potential bioavailability status in these systems.     

Use of the aquatic lichen Dermatocarpon luridum as bioindicator of copper pollution: accumulation and cellular distribution tests

Laboratory experiments were conducted to investigate the potential use of the aquatic lichen Dermatocarpon luridum as bioindicator of copper pollution. Lichen thalli were exposed to 0.00, 0.25, 0.50, 0.75 and 1.00 mM copper in synthetic freshwater to solve the problems of metal bioavailability. The mineral composition of this media was prepared so that it corresponded to the ion composition of natural waters in D. luridum ecosystems. Sequential elution procedures using NiCl2 or Na2-EDTA (20 mM) were used to determine the distribution of metals at different cellular sites. The copper concentration extracted from thalli was correlated with pollution intensity, the greater correlation being with the Na2-EDTA extractant. The malondialdehyde concentration in thalli can be used as indicator of copper pollution; however, similar membrane degradation was observed for 0.25 and 0.50 mM copper and for 0.75 and 1.00 mM copper.     

Phenological development stages variation versus mercury tolerance,accumulation, and allocation in salt marsh macrophytes <Emphasis Type="Italic">Triglochin maritima</Emphasis> and <Emphasis Type="Italic">Scirpus maritimus</Emphasis> prevalent in Ria de Aveiro coastal lagoon (Portugal)

Efficient and sustainable management of rapidly mounting environmental issues has been the focus of current intensive research. The present study aimed to investigate the impact of plant phenological development stage variation on mercury (Hg) tolerance, accumulation, and allocation in two salt marsh macrophytes Triglochin maritima and Scirpus maritimus prevalent in historically Hg-contaminated Ria de Aveiro coastal lagoon (Portugal). Both plant samples and the sediments vegetated by monospecific stands of T. maritima and S. maritimus were collected from reference (R) and sites with moderate (M) and high (H) Hg contamination in Laranjo bay within Ria de Aveiro lagoon. Hg tolerance, uptake, and allocation in T. maritima and S. maritimus, physico-chemical traits (pH, redox potential, and organic matter content) and Hg concentrations in sediments vegetated by these species were impacted differentially by phenological development stages variation irrespective of the Hg contamination level. In T. maritima, Hg concentration increased with increase in Hg contamination gradient where root displayed significantly higher Hg followed by rhizome and leaf maximally at H. However, in S. maritimus, the highest Hg concentration was perceptible in rhizome followed by root maximally at M. Between the two studied plant species, S. maritimus displayed higher Hg tolerance index (depicted by higher plant dry mass allocated to reproductive stage) and higher available Hg at M (during all growth stages) and H (during senescent stage) when compared to T. maritimus. Both plant species proved to be Hg excluder (low root/rhizome–leaf Hg translocation). Additionally, T. maritima also acted as Hg stabilizer while, S. maritimus as Hg accumulator. It can be inferred from the study that (a) the plant phenological development stage variations significantly influenced plant Hg sensitivity by impacting sediment chemistry, plant growth (in terms of plant dry mass), Hg accumulation, and its subsequent allocation capacity, contingent to Hg contamination gradient; (b) S. maritimus accumulated higher Hg but restricted its translocation to above-ground part using exclusion process at both M and H due to its accelerated growth during Hg-tolerant reproductive/metabolically active phenological development stage greater than its counterpart T. maritima; and (c) the studied salt marsh plants although hailed from the same C3 and monocot group did not necessarily display similar phenotypic plasticity and behavior towards Hg-contaminated scenario during their life cycle.     

Learning About the History of Landscape Use for the Future: Consequences for Ecological and Social Systems in Swedish Bergslagen

Barriers and bridges to implement policies about sustainable development and sustainability commonly depend on the past development of social–ecological systems. Production of metals required integration of use of ore, streams for energy, and wood for bioenergy and construction, as well as of multiple societal actors. Focusing on the Swedish Bergslagen region as a case study we (1) describe the phases of natural resource use triggered by metallurgy, (2) the location and spatial extent of 22 definitions of Bergslagen divided into four zones as a proxy of cumulative pressure on landscapes, and (3) analyze the consequences for natural capital and society. We found clear gradients in industrial activity, stream alteration, and amount of natural forest from the core to the periphery of Bergslagen. Additionally, the legacy of top-down governance is linked to today’s poorly diversified business sector and thus municipal vulnerability. Comparing the Bergslagen case study with other similar regions in Russia and Germany, we discuss the usefulness of multiple case studies.     

Synergistic effect of Eugenia jambolana Linn. and Solidago canadensis Linn. leaf extracts with deltamethrin against the dengue vector Aedes aegypti Linn. at Mysore

With the goal in mind to minimize the application of environmentally hazardous chemical insecticides, the larvicidal activity of two plant extracts along with deltamethrin was studied at University of Mysore. The extracts of Solidago canadensis and Eugenia jambolana were employed for working out the synergistic efficacy against Aedes aegypti larvae, as the extracts of both the plants exhibited high efficacy when applied individually. The deltamethrin when analyzed separately, LC₅₀ and LC₉₀ values were 0.00045 and 0.00148 ppm, respectively. Synergistic studies with two plant extracts on deltamethrin revealed S. canadensis as more effective with synergistic factor(SF) of 4.090 for LC₅₀ value and 4.781 for LC₉₀ followed by E. jambolana with SF 1.80 for LC₅₀ and 2.467 for LC₉₀ at 1:1 ratio of the phytoextracts and deltamethrin. Thus, S. canadensis was found to be a better larvicidal and synergistic agent. Combination of phytochemical and insecticide were found to be more effective than insecticides or phytochemicals alone which could be a good ecofriendly and cost-effective approach to reduce the dose of chemicals with high residual effect to be applied in vector control programs.     

Elucidation of lead-induced oxidative stress in Talinum triangulare roots by analysis of antioxidant responses and DNA damage at cellular level

Hydroponic experiments were performed with Talinum triangulare (Jacq.) Willd. focusing the root cellular biochemistry with special emphasis on DNA damage, structural, and elemental analyses in Pb(NO₃)₂ exposed with 0, 0.25, 0.5, 0.75, 1.0, and 1.25 mM for 7 days. Lead (Pb) increased reactive oxygen species production, lipid peroxidation, protein oxidation, cell death, and DNA damage and decreased the protein content in a dose-dependent manner. Likewise, a dose-dependent induction of antioxidative enzymes superoxide dismutase and catalase by Pb was evident. Ascorbate peroxidase on the other hand responded biphasically to Pb treatments by showing induction at low (0.25 and 0.50) and repression at high (0.75–1.25 mM) concentrations. The estimation of proline content also indicated a similar biphasic trend. Scanning electron microscope and energy-dispersive X-ray spectroscopy analysis showed that 1.25 mM Pb treatment resulted in ultrastructural modifications in roots and stem tissue that was marked by the change in the elemental profile. The findings pointed to the role of oxidative stress in the underlying Pb phytotoxicity and genotoxicity in T. triangulare.