Three-year lifecycle,large body,and very high threshold temperature in the cricket <Emphasis Type="Italic">Gryllus argenteus</Emphasis> for special adaptation to desiccation cycle in Malawi

In temperate climates, the initiation and termination of diapause synchronize the stress-tolerant stage with the stressful season and reproduction with the non-stressful season in many insects. Synchronization is often regulated by photoperiodism.Voltinism and the ultimate size of adults are also important determinants for their lifecycle, and different diapause stages and voltinism patterns are known in crickets.Here, we investigated the life history of the African cricket Gryllus argenteus from Malawi, which is a typical arid tropical highland. The climate is characterized by alternating arid and wet seasons, each of which lasts for half a year, and where the available heat mass is much less than lowlands at the same latitude. We first measured the nymphal duration at each rearing temperature and calculated the lower developmental threshold (t ₀) to be 20.19 °C based on Ikemoto and Takai (2000) and 19.38 °C based on a conventional line-fitting method. These values are very high relative to many other insects. The local temperature in winter does not fall below 15 °C, but this is much higher than the lethal limit. This suggested that critical stress in this locality was not coldness but low precipitation in winter. We estimated, based both on local temperature change and the Ikemoto and Takai’s t ₀, that G. argenteus required 3 years to complete its lifecycle unlike wet lowland species, where univoltinism or multi-voltinism are commonplace. Photoperiodism was observed in this species, but due to a lag between annual cycles in photoperiod, temperature, and humidity, photoperiodism alone cannot atune their lifecycle with local conditions.Synchronization in this species was achieved by three different adaptations: photoperiodism, high t ₀, and large body size, which give it a long lifecycle. Although the species cannot achieve a univoltine lifecycle because of its high t₀ value, it can escape from dry season by entering diapause at moderate temperatures, probably thereby achieving adaptive synchrony of lifecycle with both favorable and unfavorable seasons. A comparison between a conventional photothermogram and a newly formulated photohydrogram or photohygrogram demonstrates that even though sufficient heat is available, scarcity of water and thus scarcity of foliage should force the cricket to maintain diapause at intermediate temperature. The results suggested that high t ₀, large body size, and multi-ennial lifecycle mutually affect each other and formulate a unique adaptation under such an extreme environment.     

Hans-Joachim Schallna? (1957–2007)

Ohne Zusammenfassung     

Treibhausgasemissionen zukünftiger Erdgasbereitstellung für Deutschland

Ohne Zusammenfassung Original erschienen in UWSF – Z Umweltchem ?kotox 20(2):133–144 (2008) DOI: Herausgeber: Martin Pehnt und Eckard Helmers     

Phosphorus removal from municipal wastewater by hydrous ferric oxide reactive filtration and coupled chemically enhanced secondary treatment: part I--performance.

This work examines the performance of a hydrous ferric oxide (HFO) reactive filtration (RF) process with coupled chemically enhanced secondary treatment (RECYCLE) for phosphorus removal from municipal wastewater (HFO-RF-RECYCLE). A 3-month, 0.95-ML/d (0.25-mgd) demonstration of HFO-RF-RECYCLE was performed at a municipal wastewater treatment plant equipped with oxidation ditches and secondary clarifiers. Influent to the plant averaged 6.0 mg/L phosphorus, with a tertiary effluent average of 0.011 mg/L phosphorus. Iron doses to the plant were low, at 5 mg/L. Inline recycling of HFO solution rejects to the plant influent resulted in a maximum 90.3%, dose-dependent reduction of phosphorus in the secondary effluent at 4.5 ML/d (1.2 mgd). Other results included reduction of total suspended solids and turbidity. A mass balance analysis was performed. We conclude that HFO-RF-RECYCLE may allow very low levels of phosphorus discharge from municipal wastewater treatment plants with a ferric-iron-based tertiary filtration process and residual recycling.     

Aerobic and anaerobic transformations of sulfide in a sewer system--field study and model simulations.

The formation and fate of sulfide in a force main and a downstream-located gravity sewer were investigated in an extensive field study. Sulfide formation in the force main was significant. However, during 14 minutes of transport in the gravity sewer, the sulfide concentration decreased 30%, on average. An application of a conceptual sewer process model for simulating the formation and fate of sulfide was demonstrated. Overall, the model predicted that approximately 90% of the decrease of the sulfide concentration in the gravity sewer was the result of sulfide oxidation and that only a small fraction entered the sewer atmosphere, causing odor and corrosion. Even so, the model predicted concrete corrosion rates of up to 1.2 mm/y in the gravity sewer section.     

High levels of organochlorines in mothers' milk from Chennai (Madras) city, India

Mothers' milk from Chennai (formerly Madras), India and three other places Perungudi, the municipal dumping site of south Chennai area (situated at the suburb of Chennai), Chidambaram, a predominantly agricultural town situated 250 km south of Chennai and Parangipettai, a fishing village 15 km north of Chidambaram, all situated at or near the southeastern Bay of Bengal coast of India were found to contain measurable concentrations of HCHs, DDTs, PCBs, CHLs and HCB. A notable finding in this study is that Chennai mothers have higher levels of HCHs in their milk and hence may transfer considerably higher amounts of the chemical than the mothers from all the other three places of the present study indicating a higher health risk to Chennai's children. It was also found that the levels of the two organochlorine pesticides (HCHs and DDTs) increased in Chennai mothers' milk in the last decade. Food items collected from Chennai markets did not show any remarkably higher levels of any of the chemicals measured in this study. Levels of the two classical organochlorines (DDTs and HCHs) have declined in many of the food items when compared with our data collected two decades before in the same locations, showing the effectiveness of the recent ban on both these chemicals in the country. The sources, possible health risks and the ways to curtail the effects of HCHs, especially at Chennai, should be investigated further.     

Historical and geographical aspects of the increasing perfluorooctanoate and perfluorooctane sulfonate contamination in human serum in Japan

Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) have recently received attention due to their widespread contamination in the environment, as well as in wildlife and humans. We measured the PFOS and PFOA concentrations in historically recorded human serum samples at an age range between 20 and 59 years collected in Kyoto, 20 persons per each time point (n=100), and also the PFOS and PFOA concentrations in human serum samples at an age range between 20 and 59 years from 10 locations throughout Japan (n=200). The historical samples collected from 1983 to 1999 demonstrated that the PFOA concentrations in males and females from Kyoto have increased 4.4-fold and 4.3-fold at a rate of increase of 0.49 ng/ml/year and 0.42 ng/ml/year, respectively. In contrast, serum concentrations of PFOS reached a plateau in the late 1980s. There are also regional differences in both the PFOS and PFOA serum concentrations. The concentrations in serum [geometric mean (geometric standard deviation)] (ng/ml) in 2003-2004 ranged from 7.6(1.6) in the town of Matsuoka in Fukui prefecture to 27.8(1.6) in Kyoto city, and ranged from 2.3(1.5) in Matsuoka to 14.5(1.3) in Osaka city for PFOS and PFOA, respectively.     

Persistent organochlorines in raccoon dogs (Nyctereutes procyonoides) from Japan: Hepatic sequestration of oxychlordane

The present study determined the accumulation features of persistent organochlorines (OCs) such as polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), and chlordane compounds (CHLs) in wild raccoon dogs (RDs; Nyctereutes procyonoides) collected from Kanagawa prefecture in Japan during 2001. In livers of RDs, CHLs were remarkably dominant (20 times higher than PCBs) followed by PCBs>DDTs>HCHs>HCB, whereas the chemicals in muscles were in the order of CHLs>PCBs>HCHs>DDTs>HCB. The accumulation pattern of OCs in RDs was different from those in Japanese humans and avian species reported previously, which generally accumulate higher levels of DDTs and PCBs than CHLs. This result indicates that RDs have been exposed to relatively high levels of CHLs and have high metabolic and elimination capacity for DDTs. In fact, CHL levels in RDs were higher than those in humans and some avian species, while DDT levels in RDs were much lower than other animals. In particular, extremely high accumulation levels of oxychlordane, which is a metabolite from chlordanes and nonachlors, were observed in RD livers. The higher toxic potency of oxychlordane than parent compounds may suggest that RDs are at high risk by this metabolite. On lipid weight basis, PCBs, HCHs and HCB levels were almost similar in livers and muscles, suggesting that the tissue distribution of these compounds principally followed the lipid-dependent accumulation. However, accumulation levels of oxychlordane and p,p'-DDD in livers were significantly higher than those in muscles, and concentration ratios of liver to muscle (L/M ratios) of these compounds were greater than 1.0 in all the specimens. This phenomenon was similar to PCDD/DF congener accumulation patterns observed previously in RDs. When relationships between hepatic TEQs and L/M ratios were examined for oxychlordane and p,p'-DDD, L/M ratios for these compounds significantly increased with hepatic TEQ levels, suggesting their hepatic sequestration in TEQs-dependent manner.