Oily substances from gastral intersegmental glands of the antPachycondyla tridenta (Ponerinae): Lack of pheromone function in tandem running and antibiotic effects but further evidence for lubricative function

Summary Gas chromatographic analyses of volatizable material from gaster intersegmental complex glands ofP. tridentata revealed the presence of linoleic acid, palmitic acid, methyl oleate, and several long-chain hydrocarbons as major constituents, which form an oily fluid mixture. The nest relocation communication ofP. tridentata is tandem running. Tandem following is mediated by pheromones as demonstrated by dummy experiments with isolated gasters and thoraces and with glass balls. The secretions of all gaster complex glands, as well as hind gut contents and metapleural gland secretions, were unable to evoke tandem following. Morphology and position of the glands, lack of pheromonal function, oily properties, low volatility, and lack of antibiotic effects of these secretions strongly suggest a function as lubricants for the ants' gastral segments.     

绿色润滑剂的研究及进展

文章综述了国内外绿色润滑剂的研究及发展现状；简要地介绍了绿色润滑剂的特点、应用情况以及一些常用的生物降解性和毒性及生态毒性的测试方法与标准；分析了其发展所面临的挑战；并展望了其在2l世纪的发展趋势与应用前景。     

Quantal response of Paleomonetes africanus in locally formulated drilling mud lubricants

The toxic potency of three locally formulated drilling mud lubricants against Paleomonetes africanus, a brackish water crustacean commonly found in the oil producing Niger Delta (Nigeria), was evaluated. A 96?h exposure to quantal (lethal) doses of the mud lubricants gave LC₅₀ (median lethal concentration) of 350, 620 and 210?mg?L^?1, respectively. The mud lubricant with the highest molecular weight of 40,000?g?mol^?1 (lubricant 2) had the least toxicity on the organisms, attributable to the reduced rate of diffusion into the vital cells of the test organism. The higher toxicity of lubricant 3 over lubricant 1, despite its higher molecular weight, might be as a result of its higher acid value of 21.60?mg?KOH?g^?1. The results show that the test lubricants would be environmentally friendly within the baseline concentrations and lethal times (LT₅₀) measured.     

Environmental assessment of ester-based lubricants after application

GOAL, SCOPE AND BACKGROUND: Lubricants based on renewable resources are an environmentally friendly alternative to petrochemical products due to their better ecotoxicological performance and their excellent biodegradability. To improve the technical performance of lubricants, and to reduce friction and wear, the use of additives is nowadays obligatory. The collaborative research center SFB 442 aims at developing environmentally acceptable lubricants that facilitate the avoidance of these additives by transferring their function to suitable coatings. For a complete assessment of the ecological performance of these newly developed lubricants, the whole life cycle including production, application as well as disposal and fate in the environment is studied. In the following study the focus was on the application and its influence on the environmental behavior of the lubricant. The application of lubricants leads, among other things, to the intake of metals due to abrasion from tools, work pieces or mechanical components. Previous examinations indicated a possible influence of metals on the toxicity of eluates prepared from used lubricants (Erlenkaemper et al. 2005). To clarify if the apparent toxicity of used lubricants solely results from the intake of metals, the extractability of these metals from the oil matrix is determined. By combining chemical analyses with bioassays, the bioavailability of metals that are present in the extract is estimated. To further investigate the relevance of metals on toxicity, toxic units (TU) were calculated and related to the results of the bioassays. Interactions between the metals were investigated with aqueous mixtures of metal chlorides and calculations based on the concept of concentration addition and independent action. METHODS: A lubricant mixture was applied to a tribological test bench that simulates real conditions of use and extremely short time load, respectively. Samples were taken at particular times, water soluble fractions (WSF) of these fluids were prepared and dilution series were investigated in several bioassays. Concentration of metals and total organic carbon (TOC) were determined in the eluates. TUs were calculated according to Sprague (1970) and mixture toxicity was calculated according to the concept of concentration addition (Loewe and Muischnek 1926) and independent action (Bliss 1939). RESULTS: Analyses of the metal content of the lubricant and the eluates clearly revealed the availability of the metals in the aqueous extracts. Especially copper, zinc, nickel and chromium were found and their concentrations increased during the time of use. The water extractable fraction, e.g., of copper, rose from 8.8% to 45.3% of the total content in the lubricant after 33.5 hours of use. Tests performed with the algal growth inhibition assay and the luminescence inhibition assay revealed the uptake or absorption by the organisms and, thus, the bioavailability of the metals. The calculation of TUs partly indicated a possible influence of the metals on ecotoxicity of the eluates. Copper reached concentrations equal to or higher than the EC50 value of copper chloride in the growth inhibition assays with algae and Ps. putida as well in the immobilization assay with daphnids. TUs for copper are also larger than 1 for the algal growth inhibition assay. The EL50 values indicated that the luminescence inhibition assay was the most sensitive test system, with values between 4.7% and 9.6%. While the toxicity towards algae and V. fischeri in the growth inhibition assay decreased until both organisms were no longer influenced by the exposure, the EL50 values for the D. magna immobilization assay and the Ps. putida growth inhibition assay decreased with the progressing use of the lubricant. The tested metal salt mixtures showed that Ps. putida, algae and daphnids are the most sensitive organisms with EC50 values below 1 mg/l. DISCUSSION: Although the intake of metals mainly occurred via abrasion of particles, the results revealed the availability of these metals in water. The availability varied for each of the four metals. For both the algal growth inhibition assay and the luminescence inhibition assay, an uptake or absorption of the metals could be demonstrated. The calculated TUs indicated an effect in some bioassays that was not verified in the test itself. The influence of copper on V. fischeri, for example, was not confirmed while the EL50 values for the daphnid bioassay decreased, meaning that the eluates became more toxic with progressing use of the lubricant. The calculations of mixture toxicity based on the concept of concentration addition demonstrated good correlations with the tested metal mixtures, but also a different sensitivity of the organisms. CONCLUSIONS: The results presented here reveal the availability of those metals in water that were taken in during the use of the lubricant in a tribological test bench and, thus, have the possibility of interacting with the organisms. The availability of the metals in the bioassays was proven by chemical analyses. The calculation of TUs and the corresponding EL50 values, however, indicate different availabilities of the metals. The results of the metal salt mixtures show good correlations with calculations of mixture toxicity based on concentration addition. Moreover, the varying sensitivity of the organisms when exposed to eluates or metal mixtures indicates a different bioavailability of the metals and/or the presence of other compounds that exert toxic action. RECOMMENDATIONS AND PERSPECTIVES: For further investigations, the organic oil matrix and its influence on the toxicity have to be taken into account. The toxicity of the eluates may not only be due to metals; additional effects could arise from changes in the lubricant itself.     

Generic scenario for the impact of cooling lubricants into the hydrosphere

According to directive 93/67/EEC of the European Commission, this paper deals with the generic exposition evaluation of the environmental concentration of cooling Lubricant chemicals from the metal working industry into the hydrosphere. After considering the relevant life-cycle steps and the selection of a representative point source for the 'reasonable worst case', the emission per day Elocal(water) is determined. It leads to the predicted environmental concentration (PEClocal(water)) for the local stage in the compartment water. In order to gain the PEClocal(water) for an example--a corrosion inhibitor as additive in a cooling lubricant--, the relevant emission paths and the corresponding representative point source are described for the reasonable worst case. For non-water-miscible cooling lubricants, none of the operations in the life cycle leads to a release into the compartment water. To evaluate the hazard potential for cooling lubricant chemicals, the complete risk assessment has to be done. Also, the assessment has to be done for all high production volume chemicals, new substances and existing hazard chemicals. This means that even industrial categories like chemicals used in the textile industry or biocides and others have to be evaluated.