Investigation on the heavy-metal content of zinc-air button cells

Within the framework of a German government project (initiated by the Federal Environment Agency) to check the compliance of commercially available batteries with the German Battery Ordinance concerning their heavy metal contents, 18 different types of commercially available zinc-air button cells were analysed for their cadmium, lead and mercury contents. After microwave assisted dissolution with aqua regia, Cd and Pb were determined using inductively coupled plasma mass spectrometry (ICP-MS), and Hg was determined using inductively coupled plasma optical emission spectrometry (ICP OES) and atomic absorption spectrometry. Cd contents were found to be much lower than the permitted limits; Pb contents were also found to be below the limits. Hg contents were found to be near the limits, and in one case the limit was exceeded.     

Straßenversiegelung in Deutschland und ihre Beinflussung der Umwelt im Vergleich mit anderen OECD-Ländern

Since the increasing awareness of environmental damage, attention has focussed on the problems caused by the extension of car traffic. The number of cars has permanently increased over the years and is predicted to continue in the future. The number of cars registered worldwide already passed the number of 500 million in the year 1988 (OECD, 1995). Two major problems are linked to the increase in car traffic: The air pollution by engine conbustion and the so-called sealing of the ground by pavements. The streets dramatically cut into coherent areas, separate biotopes, animal and plant populations (BBR, 1998). Facts about grund sealing in Germany are presented and compared to those of other OECD-countries. Environmental consequences are discussed.     

Occurrence, fate and assessment of polar metamizole (dipyrone) residues in hospital and municipal wastewater

The occurrence and fate of residues from the therapeutic use of the non-steroidal anti-inflammatory drug metamizole have been studied in investigations of sewage effluents from a military hospital, municipal sewers and a sewage treatment plant (STP) in Berlin, Germany. The loads of the metabolites aminoantipyrin (AA), 4-acetylaminoantipyrin (AAA) and 4-formyl-aminoantipyrin (FAA), rapidly formed after the application of metamizole, were predicted from pharmacokinetic data and based on the evaluation of extensive data sets of on the administration in hospitals and private households. In parallel, the actual concentrations were measured within three field trials. For the military hospital, the estimated average annual discharges of AA/AAA and FAA were 10.5 and 3.2 kg, respectively. For the STP, annual loads of 333 and 133 kg were determined for AA/AAA and FAA, respectively. During sewage treatment, an average decrease of 26% of the loads was measured for AA/AAA whereas no changes were observed for FAA. Generally, the prediction of the loads resulted in an overestimation of the residue levels compared to those measured in the respective sewers. Thus, modeling of predicted loads or concentrations alone will not be sufficient for a realistic assessment. Concerns for human or other mammals' health are not expected from the occurrence of metamizole residues in the aquatic system measured at concentrations up to 7 microg l(-1) in STP effluents. However, a rest of uncertainty remains as it was not possible to derive a no observed effect level for the induction of rare but potentially fatal toxicological side effects reported for metamizole.     

Interactive effects of disturbance and dispersal directionality on species richness and composition in metacommunities

Dispersal among ecological communities is usually assumed to be random in direction, or to vary in distance or frequency among species. However, a variety of natural systems and types of organisms may experience dispersal that is biased by directional currents or by gravity on hillslopes. We developed a general model for competing species in metacommunities to evaluate the role of directionally biased dispersal on species diversity, abundance, and traits. In parallel, we tested the role of directionally biased dispersal on communities in a microcosm experiment with protists and rotifers. Both the model and experiment independently demonstrated that diversity in local communities was reduced by directionally biased dispersal, especially dispersal that was biased away from disturbed patches. Abundance of species (and composition) in local communities was a product of disturbance intensity but not dispersal directionality. High disturbance selected for species with high intrinsic growth rates and low competitive abilities. Overall, our conclusions about the key role of dispersal directionality in (meta)communities seem robust and general, since they were supported both by the model, which was set in a general framework and not parameterized to fit to a specific system, and by a specific experimental test with microcosms.     

Photosynthesis mediated decrease in cadmium translocation protect shoot growth of Oryza sativa seedlings up on ammonium phosphate – sulfur fertilization

Cadmium (Cd) stress responses in seedlings of two Indian rice cultivars, MTU 7029 and MO 16 were investigated under ammonium-based fertilizer amendment. Cd translocation was reduced by fertilizer treatment. An increase in the production of organic acids as well as nitrogenous compounds and maintenance of nutrient status were implicated for decrease in Cd translocation which in turn promoted shoot growth. Fertilizer treatment increased photosynthetic pigments and activity of antioxidant enzymes that ensured steady photosynthetic rate during Cd stress. MO 16 showed Cd exclusion characteristics when compared with MTU 7029. Photosynthesis performance of MO 16 was not affected by Cd treatments. These findings suggest that photosynthesis influenced decrease in Cd translocation enhanced shoot growth of seedlings during ammonium phosphate–sulfur fertilizer supplementation.     

Photoinhibition of Symbiodinium spp. within the reef corals Montastraea faveolata and Porites astreoides: implications for coral bleaching

It is speculated that differences in coral bleaching susceptibility may be influenced by the genotype of in hospite Symbiodinium and their differential responses to bleaching stressors. Photoinhibition of photosystem II (PSII), damage to the D1 (psbA) PSII reaction centre protein and production of reactive oxygen species by in hospite Symbiodinium are likely precursors of coral bleaching. In order to assess whether photorepair rates of in hospite Symbiodinium underlie the bleaching susceptibility of their hosts, photoinhibition (net and gross), photoprotection and photorepair rates were assessed in a bleaching-‘tolerant’ coral (P. astreoides) and a bleaching-‘sensitive’ coral (M. faveolata) using non-invasive fluorometric techniques and by blocking de novo synthesis of psbA. Previous studies using such techniques have demonstrated that in vitro Symbiodinium types ‘sensitive’ to bleaching stressors had reduced rates of photorepair relative to ‘tolerant’ Symbiodinum types. Our measurements demonstrated that Symbiodinium in the more bleaching tolerant P. astreoides had higher photorepair rates than Symbiodinium in M. faveolata. Higher repair rates in P. astreoides resulted in lower net photoinhibition relative to M. faveolata, where both corals exhibited similar susceptibility to photodamage (gross photoinhibition). Photoprotective mechanisms were observed in both corals; M. faveolata exhibited higher antennae-bed quenching than P. astreoides at low-light intensities, but at and above light-saturating intensities, which are different for each coral species, P. astreoides displayed more efficient non-photochemical quenching (Stern–Volmer quenching) of chlorophyll fluorescence than M. faveolata. Increased NPQ by P. astreoides at E/E _k ≥ 1 was not driven by antennae-bed quenching. The ability of in hospite Symbiodinium in P. astreoides to mitigate the effects of photoinhibition under high light conditions compared with Symbiodinium in M. faveolata, and their high repair capacity following photoinhibition, may be a key factor to consider in future bleaching studies and may underlie the relative bleaching tolerance of P. astreoides compared to M. faveolata.     

Pesticide risk mitigation by vegetated treatment systems: a meta-analysis

Pesticides entering agricultural surface waters threaten water quality and aquatic communities. Recently, vegetated treatment systems (VTSs) (e.g., constructed wetlands and vegetated ditches) have been proposed as pesticide risk mitigation measures. However, little is known about the effectiveness of VTSs in controlling nonpoint source pesticide pollution and factors relevant for pesticide retention within these systems. Here, we conducted a meta-analysis on pesticide mitigation by VTSs using data from the scientific literature and the European LIFE ArtWET project. Overall, VTSs effectively reduced pesticide exposure levels (i.e., the majority of pesticide retention performances was >70%). A multiple linear regression analysis of 188 retention performance cases identified the two pesticide properties, organic carbon sorption coefficient value and water-phase 50% dissipation time, as well as the VTS characteristics overall plant coverage and hydraulic retention time for targeting high efficacy of pesticide retention. The application of a Tier I risk assessment (EU Uniform Principle) revealed a higher toxicity reduction for hydrophobic and nonpersistent insecticides compared with less sorptive and not readily degradable herbicides and fungicides. Overall, nearly half (48.5%) of all pesticide field concentrations ( = 130) failed Tier I standard risk assessment at the inlet of VTSs, and 29.2% of all outlet concentrations exceeded conservative acute threshold levels. We conclude that VTSs are a suitable and effective risk mitigation strategy for agricultural nonpoint source pesticide pollution of surface waters. Further research is needed to improve their overall efficacy in retaining pesticides.     

Division of labor and slave raid initiation in slave-making ants

In social insect societies, division of labor, i.e., workers of a colony specializing in different tasks, is thought to improve colony performance. Workers of social parasitic slave-making ants focus on a single task, searching for and raiding host colonies to replenish their slave workforce. However, in the North American slavemaker Protomognathus americanus, some workers do not partake in raids but remain inside the colony. We analyzed raid participation, fertility, and cuticular hydrocarbon profiles of slavemaker workers and slaves to understand these behavioral differences and the regulation of division of labor in slavemaker colonies. Raid observations showed that some workers were repeatedly involved in raiding activities (exterior workers), whereas others stayed inside the nest (interior workers). Exterior workers were always infertile, while half of the interior workers were fertile. Analysis of cuticular hydrocarbons demonstrated differences between the groups. We also detected chemical differences between interior and exterior slaves, indicating an influence of the individuals’ tasks on their cuticular profiles. Task- and fertility-related profiles may allow selective nestmate recruiting. Division of labor should also adapt to varying conditions. Since slave raids are dangerous, they should only be initiated when the colony needs additional slaves. Exclusively fed by their slaves, slavemaker workers could determine this need via their nutritional status. In an experiment with various feeding regimes, colonies subjected to a lower food provisioning rate showed increased proportions of slavemaker workers searching for host colonies. Division of labor in slave-making ants, therefore, might be flexible and can change depending on the colonies’ needs.