Testing the ecotoxicology of vegetable versus mineral based lubricating oils: 1. Degradation rates using tropical marine microbes

Vegetable-derived lubricants (VDL) might be more biodegradable than mineral-derived lubricants (MDL) due to the absence of high molecular weight aromatics, but this remains largely untested in tropical conditions. In this laboratory study, the degradation rates of 2-stroke, 4-stroke and hydraulic VDLs were compared with their MDL counterparts in the presence of mangrove and coral reef microbial communities. While MDLs were comprised largely of unresolved saturated and some aromatic hydrocarbons, their VDL counterparts contained, potentially more degradable, fatty acid methyl esters. Degradation of some VDL was observed by day 7, with the 2-stroke VDL markedly consumed by mangrove microorganisms and the hydraulic VDL degraded by both microorganism communities after this short period. All of the VDL groups were significantly more degraded than the comparable MDLs mineral oil lubricants over 14 days in the presence of either mangrove or coral reef microbial communities. In general the mangrove-sourced microorganisms more efficiently degraded the lubricants than reef-sourced microorganisms.     

Investigations on the effect of chlorine in lubricating oil and the presence of a diesel oxidation catalyst on PCDD/F releases from an internal combustion engine

This paper reports on an intensive study into releases of polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated furans (PCDF) and polychlorinated biphenyls (PCB) from a diesel engine and the analysis of PCDD/F and PCB in crankcase lubricating oil. Experimental conditions were set and carefully controlled in order to maximize the possible impact of, and our ability to measure the effect of, changes in the levels of chlorine in the lubricant. Emissions to air were measured using modified EPA methods following the principles of the European EN 1948 standards. A series of 40 experimental runs were completed using three reference lubricants formulated to have three levels of chlorine present as a residual component (at levels of 12, 131 and 259 mg kg(-1) or ppm). The engine was run with and without the diesel oxidation catalyst. All lubricants were realistic oils and the use of unrealistic additives or doping of components - particularly chlorine - in the fuel and lubricant was carefully avoided. Analysis of fuel and lubricant (before and after testing) samples required strenuous attention to achieve acceptable recoveries and showed non-detectable levels of PCB and PCDD/F at a detection limit of around 1.5 ng I-TEQ kg(-1) (ppt), indistinguishable from the laboratory blank. The testing demonstrated the need for extreme care to be taken in developing measurement methods that are sufficiently sensitive for measuring chlorine content of fluids and PCDD/F in oils, the latter being particularly challenging. Mean emissions of PCDD/F with the diesel oxidation catalyst in place were 23 pg I-TEQ l(-1) of fuel and with the diesel oxidation catalyst removed 97 pg I-TEQ l(-1) of fuel. The results of this testing showed that the emissions of PCDD/F were greatly reduced by the presence of a diesel oxidation catalyst in the exhaust, a finding that has not been explicitly tested in previous work. They also show that emissions from the engine were not controlled by the level of chlorine in the lubricant and that emissions did not change in response to a much greater step change in the total chlorine entering the combustion chamber due to a change in the level of chlorine in the fuel. Emissions when the engine was configured with a diesel oxidation catalyst showed a consistent pattern that appears to be unique in the experience of the authors.     

Risk assessment for hazardous lubricants in machining industry

Knowing that over two-thirds of lubricant disposals return to the environment with no purification process, adequate strategies are demanded to reduce their risks. For this reason, the main focus of the present study is to describe an environment-friendly approach. In the first part, two widely used lubricants (mineral-based and vegetable-based) were introduced, and the reasons for their hazards were investigated. The composition of mineral-based lubricant was characterized by x-ray fluorescence elemental analysis. The result showed the presence of phosphorus, chlorine, and zinc dialkyl dithiophosphate in its composition that many scholars considered them to be the leading risk factor in the chemical composition of mineral-based lubricants. It has been focused on the potential risks of vegetable-based lubricants, which many researchers have identified as a safe lubricant. The Pseudomonas microbe was cultivated in the vegetable-based sample, and the result showed that although vegetable-based lubricants are compatible with humans, bacteria colony can quickly grow there without making any apparent changes that lead to harm to operators in a mysterious way. In the present work, the hypothesis of the safety of unreinforced vegetable-based lubricants has been rejected, and a new window on the environmental issues of vegetable-based lubricants has been presented. In the final, to eliminate environment-human risks and to reduce consumption of lubricant and natural resources to green manufacturing, a comprehensive study on the possibility of completely removing lubricant was performed. The results showed that the machining without lubricant could be replaced with the traditional method.

     

Black Disease (Terpios hoshinota): A Probable Cause for the Rapid Coral Mortality at the Northern Reef of Yongxing Island in the South China Sea

The northern reef of Yongxing Island, the largest reef island of the Xisha Islands in the South China Sea, was in good condition with significant cover of scleractinian corals until 2002. Surveys in 2008 and 2010, however, found that coral coverage had declined rapidly and severely, implying that catastrophic coral mortality occurred during the past 8 years. A blackish mat was observed covering live and dead corals in both 2008 and 2010 that was identified as an encrusting sponge, Terpios hoshinota, by special surface morphology and spicule structure. In addition, spicule residues were found on the surface of long-dead corals, indicating a previous invasion of T. hosinota. T. hoshinota is referred to as the "black disease" because it rapidly overgrows and kills corals. Our evidence indicates that outbreaks of black disease are at least partially responsible for the massive coral mortality at the northern reef of Yongxing Island over the past 8 years, although human activities and heat-related coral bleaching cannot be discounted as minor causes for this coral decline.     

Effects of pharmaceuticals on Daphnia survival, growth, and reproduction

Pharmaceuticals have been globally detected in surface waters, and the ecological impacts of these biologically-active, ubiquitous chemicals are largely unknown. To evaluate the aquatic toxicity of individual pharmaceuticals and mixtures, we performed single species laboratory toxicity tests with Daphnia magna, a common freshwater zooplankton. We conducted acute (6-day) and chronic (30-day) exposure pharmaceutical bioassays and evaluated survivorship and morphology of adults and neonates, adult length, resting egg production, brood size (fecundity), and the proportion of male broods produced (sex ratio). In general, exposure to a single pharmaceutical in the 1-100 microg/l range yielded no apparent effects on the normal life processes of Daphnia. However, chronic fluoxetine exposure (36 microg/l) significantly increased Daphnia fecundity, and acute clofibric acid exposure (10 microg/l) significantly increased sex ratio. A mixture of fluoxetine (36 microg/l) and clofibric acid (100 microg/l) caused significant mortality; the same fluoxetine concentration mixed with 10 microg/l clofibric acid resulted in significant deformities, including malformed carapaces and swimming setae. Mixtures of three to five antibiotics (total antibiotic concentration 30-500 microg/l) elicited changes in Daphnia sex ratio. We conclude: (1) individual and mixtures of pharmaceuticals affect normal development and reproduction of Daphnia magna, (2) aquatic toxicity of pharmaceutical mixtures can be unpredictable and complex compared to individual pharmaceutical effects, and (3) timing and duration of pharmaceutical exposure influence aquatic toxicity.     

Evaluation of municipal sewage treatment systems for pollutant removal efficiency by measuring levels of micropollutants

In order to evaluate the municipal sewage treatment systems used at Harbin municipal sewage treatment plant for their pollutant removal efficiency, raw sewage and effluent samples at different treatment stages from the sewage treatment systems were taken, priority pollutants (PPs) were identified and quantified using gas chromatography-mass spectrometry (GC-MS) and inductively coupled plasma-atomic emission spectrograph (ICP-AES). The test results indicated that there were one hundred and fifty species of organic pollutants identified in the raw sewage sample, and only ten species of PPs in all the sewage samples. The levels of dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), di-n-octyl phthalate (DnOP) in the sewage samples were 0.779-0.111 microg l(-1), 1.977-0.022 microg l(-1), 6.411-2.194 microg l(-1) and 7.152-2.953microg l(-1), respectively, and most of these phthalate esters (PAEs) were removed through anaerobic/aerobic (A/O) process; The levels of alachlor, acetochlor, atrazine were 0.074-0.021 microg l(-1), 0.160-0.096 microg l(-1) and 0.238-0.184 microg l(-1), respectively, and the total removal efficiency of atrazine was poorest through the sewage treatment systems. The levels of Cu, Cr, Se, Hg, Ni and Zn were 0.0030-0.2327 mg l(-1). It is therefore concluded from these results that the sewage treatment systems were efficient in removing most of the organic and inorganic compounds in this study, and so, the discharged effluent could cause little of the secondary pollution of the aquatic environment.     

Reproductive effects and bioconcentration of 4-nonylphenol in medaka fish (Oryzias latipes)

The objective of this study was to investigate the reproductive success (fertility and fecundity) of medaka (Oryzias latipes) exposed to 4-nonylphenol (4-NP) in water and the viability of their F(1) offspring. In addition, we measured the bioconcentration of 4-NP in eggs. After a 21-d exposure to 100microg/l 4-NP, medaka showed reduced egg production and fertility. Hepatic vitellogenin levels were increased significantly in males treated with 10, 50 and 100microg/l of 4-NP. In the F(1) generations, the hatchability and time to hatching of embryos in the 100microg/l treatment group were adversely affected, and 2-7microg 4-NP/g egg was found in spawned eggs (the bioconcentration factor: 30-100). These results indicate that (1) 4-NP adversely affected the reproduction (fecundity and fertility) of adult medaka, (2) 4-NP accumulated in eggs through maternal transfer and (3) these levels of 4-NP were associated with adverse effects in the F(1) offspring.     

Antioxidant responses to benzo[a]pyrene and Aroclor 1254 exposure in the green-lipped mussel, Perna viridis

In this study, the green-lipped mussel, Perna viridis (L.), was exposed to two concentrations of benzo[a]pyrene (B[a]P) (0.3 microg l(-1); 3 microg l(-1)) and two concentrations of Aroclor 1254 (0.5 microg l(-1); 5 microg l(-1)). In addition, a mixture of the contaminants was used (0.3 microg l(-1) B[a]P+0.5 microg l(-1) Aroclor 1254; 3 microg l(-1) B[a]P+5 microg l(-1) Aroclor 1254). All concentrations were nominal. A suite of enzymes [glutathione S transferase (GST), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR)], glutathione (GSH) level and lipid peroxidation (LPO) in the mussel gill and hepatopancreas were monitored over 18 days. CAT and GSH in gill tissue were positively correlated with concentration of Aroclor 1254. Activity of hepatic GST and SOD was significantly related to body burden of Aroclor 1254. LPO, GR and GPx in gill and hepatopancreas and hepatic GST were positively correlated with B[a]P concentration. The results indicate the importance of using biomarkers specific to the type of contaminant(s) that are likely to be present. Controlled laboratory experiments, such as this study, are useful in ascertaining biomarkers suitable for use with complex contaminant mixtures in the marine environment.     

Can corals be harvested sustainably?

The international trade in corals has been identified as a potential cause of localized depletion of coral populations in the major coral-exporting countries. The international coral trade is regulated by the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES) agreement, which requires that export of corals is not detrimental to the species. The primary coral importing regions (USA and Europe) have threatened to limit or ban coral imports unless sustainable practices can be demonstrated. The spatial and temporal scale at which sustainability is defined is important in evaluating sustainability, e.g. at geological, regional or local scales. Other major issues are: the ecology of the target species; management options including provision of no-take areas; and the potential for coral culture. Implementation of practices that enhance ecological sustainability in the coral harvest fishery is possible, but may be difficult in some developing countries because of limited natural-resource management capacity.     

Aflatoxin M1 contamination of milk and ice cream in Abeokuta and Odeda local governments of Ogun State, Nigeria

A survey was undertaken to determine the aflatoxin M(1) contamination of milk and some locally produced dairy products in Abeokuta and Odeda local governments of Ogun State, Nigeria. Samples of human and cow milk, yoghurt, "wara", ice cream and "nono" were collected randomly within the local governments and analysed for aflatoxin M(1) using the two-dimensional TLC. Aflatoxin M(1) contamination in the range of 2.04-4.00 microg l(-1) was noticed only in milk and ice cream. In particular, samples of human milk, cow milk and ice cream recorded high scores of 4.0 microg l(-1), 2.04 microg l(-1) and 2.23 microg l(-1), respectively in Abeokuta local governments and a score of 4.0 microg l(-1) for cow milk in Odeda local government. This indicates a high level contamination in the local governments since the weighted mean concentration of aflatoxin M1 in milk for African diet is 0.002 microg l(-1). Therefore the concentration of AFB1 in feeds which is transformed to AFM1 in milk should be reduced by good manufacturing and good storage practices. Furthermore, there is need for stringent quality control during processing and distribution of these products.     

Sulfamethazine and flubendazole in seepage water after the sprinkling of manured areas

Pharmaceuticals are widely used in modern livestock production and can reach the environment via the application of manure containing excreted drugs. Limited information is available on the transport and fate of veterinary medicines applied to soils. Therefore, we assessed the potential for the sulphonamide antibiotic sulfamethazine (SMT) and the antiparasitic drug flubendazole (FLUB) including their metabolites to move from agricultural manure to drainage waters at 1m depth. A comparison was made of losses from sites under different land use (grassland versus arable cropping) as well as losses from neighbouring plots under the same land use. Liquid manure from pigs treated with SMT and FLUB was spread on 10 x 30 m2 plots (750l per plot). SMT concentration in slurry ranged from 600 to 1700 microg l(-1) (metabolite acetyl-SMT 280-1700 microg l(-1)) and FLUB concentration ranging from 25 to 56 microg l(-1) (metabolite amino-FLUB 32-110 microg l(-1), hydroxy-FLUB 19-38 microg l(-1)). About 1h after application heavy rainfall (50mm in 2.5h) was simulated by sprinkler irrigation. Drainage flow started within 1h after the commencement of sprinkling. SMT and FLUB concentrations in leachate reached values of up to 16 microg l(-1) and 0.3 microg l(-1), respectively. Loss rates (relative to the applied amounts) from the neighbouring sites under arable cropping ranged from 2.8% to 5.4% for SMT and 0.8% to 3.1% for FLUB (including metabolites). On the permanent grassland plot, due to its multitude of macropores, loss rates reached values up to 10% for SMT and 16% for FLUB (including metabolites). These results demonstrate that the variability in leaching of veterinary drugs may be high even between large neighbouring plots, depending on site heterogeneity and land use.     

Effect of tris-(2-chloroethyl)-phosphate (TCEP) at environmental concentration on the levels of cell cycle regulatory protein expression in primary cultured rabbit renal proximal tubule cells

Tris-(2-chloroethyl)-phosphate (TCEP) is a typical organophosphate flame retardant and has been designated as a micropollutant in aquatic environment. However, the potential effect of TCEP at environmental concentration is mostly unknown. Thus, the purpose of this study was to investigate the renal effect of TCEP at environmental concentration using primary cultured rabbit renal proximal tubule cells (PTCs). The results showed that TCEP at 10 mg L(-1) decreased cell viability, 84.2% of the control, but increased lactate dehydrogenase, 150% fold of the control. TCEP at 10 mg L(-1) also inhibited expression of CDK4, cyclin D1, CDK2, and cyclin E (79.3%, 77.7%, 73.3%, and 67.8% of the control, respectively), but increased expression of p21(WAF/Cip1) and p27(Kip1) (167.7% and 141.3% of the control, respectively). TCEP decreased DNA synthesis and cell number, 77% and 70% of the control, respectively. Through study of cell viability, cell damage, cell cycle regulator expression, DNA synthesis and cell number, TCEP at 10 microg L(-1) only affected the cells that TCEP increased expression of p21(WAF/Cip1) and p27(Kip1), 118.6% and 121.5% of the control, respectively, but decreased DNA synthesis, 91.5% of the control. In conclusion, TCEP at 10 microg L(-1) significantly increased cell cycle regulatory protein expression (p21(WAF/Cip1) and p27(Kip1)), but slightly decreased DNA synthesis in primary cultured rabbit renal PTCs.     

A qualitative sampling method for monitoring water quality in temporary channels or point sources and its application to pesticide contamination

A water-sampling device to monitor the quality of water periodically and temporarily flowing out of concrete tubes, sewers or channels is described. It inexpensively and easily enables a qualitative characterization of contamination via these point-source entry routes. The water sampler can be reverse engineered with different sizes and materials, once installed needs no maintenance, passively samples the first surge, and the emptying procedure is short. In an agricultural catchment area in Germany we monitored an emergency overflow of a sewage sewer, an outlet of a rainwater sewer and two small drainage channels as input sources to a small stream. Seven inflow events were analysed for 20 pesticide agents (insecticides, fungicides and herbicides). All three entry routes were remarkably contaminated. We found parathion-ethyl concentrations of 0.3 microg l(-1), diuron up to 17.3 microg l(-1), ethofumesate up to 51.1 microg l(-1), metamitron up to 92 microg l(-1) and prosulfocarb up to 130 microg l(-1).     

Water Quality of Medium Size Watercourse Under Baseflow Conditions: The Case Study of River Sutla in Croatia

The study on medium size river Sutla in Croatia indicated considerable water contamination at specific sites during the baseflow period, probably associated to low flow-rate (0.73-68.8 m3 s(-1)), and consequently low dilution capacity of this river. Various aspects of contamination were observed: increased conductivity to 1,000 microS cm(-1), decreased dissolved oxygen level to 50%, 4-5 degrees C increased water temperature, increased concentrations of several dissolved trace elements (e.g., maximal values of Li: 45.4 microg l(-1); Rb: 10.4 microg l(-1); Mo: 20.1 microg l(-1); Cd: 0.31 microg l(-1); Sn: 30.2 microg l(-1); Sb: 11.8 microg l(-1); Pb: 1.18 microg l(-1); Ti: 1.03 microg l(-1); Mn: 261.1 microg l(-1); and Fe: 80.5 microg l(-1)) and macro elements (e.g., maximal values of Na: 107.5 mg l(-1); and K: 17.3 mg l(-1)), as well as moderate or even critical fecal (E. coli: 4,888 MPN/100 ml; total coliforms: 45,307 MPN/100 ml; enterococci: 1,303 MPN/100 ml) and organic pollution (heterotrophic bacteria: 94,000 cfu/ml). Although metal concentrations still have not exceeded the limits considered as hazardous for aquatic life or eventually for human health, the observed prominent increases of both metal concentrations and bacterial counts in the river water should be considered as a warning and incentive to protect the small and medium size rivers from the future deterioration, as recommended by EU Water Framework Directive.     

Toxic and essential trace elements in human milk from Greek lactating women: association with dietary habits and other factors

The aim of this study was to determine the concentration of some essential and toxic metals in the colostrum and transitory human milk in conjunction with various factors that may influence their concentrations i.e. diet, supplementation, place of residence, smoking, as well as socioeconomic and somatometric characteristics. Zinc, iron, copper, manganese, cadmium and lead were measured by AAS in 180 colostrum samples from healthy lactating women collected on third day postpartum. A second milk sample was collected in 95 (53%) subjects 14 days later. Dietary habits were assessed by a 7-day food frequency questionnaire and various characteristics and socio-economic factors were also recorded. The mean (+/-standard deviation) values of colostrum samples were: Zn 4905 +/- 1725 microg l(-1), Fe 544 +/- 348 microg l(-1), Mn 4.79 +/- 3.23 microg l(-1), Cu 381 +/- 132 microg l(-1), Cd 0.190 +/- 0.150 microg l(-1), Pb 0.48 +/- 0.60 microg l(-1). All metals with the exception of copper were found in lower concentrations in transitory samples. Cadmium and lead weekly intakes were found to be below the Maximum Tolerable Weekly Intakes as they have been established for infants by WHO or NRC. Our results revealed: higher Pb concentration in the samples from urban areas; effect of smoking on Cu level; dietary habits seem to play a role in metal levels in human milk as the logistic regression models revealed.     

Determination of commonly used polar herbicides in agricultural drainage waters in Australia by HPLC

The present study describes the application of different extraction techniques for the preconcentration of ten commonly found acidic and non-acidic polar herbicides (2,4-D, atrazine, bensulfuron-methyl, clomazone, dicamba, diuron, MCPA, metolachlor, simazine and triclopyr) in the aqueous environment. Liquid-liquid extraction (LLE) with dichloromethane, solid-phase extraction (SPE) using Oasis HLB cartridges or SBD-XC Empore disks were compared for extraction efficiency of these herbicides in different matrices, especially water samples from contaminated agricultural drainage water containing high concentrations of particulate matter. Herbicides were separated and quantified by high performance liquid chromatography (HPLC) with an ultraviolet detector. SPE using SDB-XC Empore disks was applied to determine target herbicides in the Murrumbidgee Irrigation Area (NSW, Australia) during a two-week survey from October 2005 to November 2005. The daily aqueous concentrations of herbicides from 24-h composite samples detected at two sites increased after run-off from a storm event and were in the range of: 0.1-17.8 microg l(-1), < 0.1-0.9 microg l(-1) and 0.2-17.8 microg l(-1) at site 1; < 0.1-3.5 microg l(-1), < 0.1-0.2 microg l(-1) and < 0.2-3.2 microg l(-1) at site 2 for simazine, atrazine and diuron, respectively.     

Effects of Cadmium and Zinc on the feeding behaviour of two freshwater crustaceans: Atyaephyra desmarestii (Decapoda) and Echinogammarus meridionalis (Amphipoda)

Lethal and sublethal effects of Cadmium and Zinc on two freshwater crustaceans were investigated. The 96-h LC50 for Cadmium and Zinc were 42.20 microg l(-1) and 5.43 mg l(-1) for Atyaephyra desmarestii, and 36.17 microg l(-1) and 4.61 mg l(-1) for Echinogammarus meridionalis, respectively. An increase in metal concentrations at sublethal levels resulted in significant reductions of the feeding rate of both species. The LOECs in the chronic feeding assays for Zinc were 1.29 mg l(-1) for A. desmarestii and 0.4 mg l(-1) for E. meridionalis. For Cadmium the LOEC was 6.53 microgl(-1) for both species. The results suggest the potential use of these two crustacean species as test organisms in ecotoxicological tests. Feeding assays appear to be a rapid, cheap and effective tool to be used in biomonitoring studies of Portuguese freshwaters.     

Speciation of inorganic arsenic in alimentary and environmental aqueous samples by using derivative anodic stripping chronopotentiometry (dASCP)

The purpose of this research was to develop a sensitive and accurate chronopotentiometric method at a gold film electrode, to determine trace and ultra trace levels of As(III) and As(V) in alimentary and environmental water systems. As(III) was directly determined in the aqueous matrix at a deposition potential of -300 mV for 180 s and at a constant anodic current of 2.5 microA, without any sample pre-treatment; moreover the chronopotentiometric method did not require a time-consuming de-oxygenation step prior to the analysis. A 3M HCl solution was chosen as the best stripping medium. The direct analysis of As(V) required the application of a high negative over-potential and, thus, measurements were characterized by poor reproducibility; therefore As(V) was determined after reduction to As(III) with KI in a strong hydrochloric acid solution. Under the optimised electrochemical conditions, detection limits of 0.08 microg As(III) l(-1) were achieved and no significant interferences from Cd, Cu, Pb, Zn and organic substances were observed. As(V) was the most abundant species in all the studied environmental and alimentary aqueous matrices. Amongst the beverages, tea and coffee presented the As(V) highest concentration ranges (934-1740 microg l(-1) and 850-1290 microg l(-1), respectively) while bottled mineral water the lowest (<1.61 microg l(-1)); whereas As(III) levels lower than 5.0 microg l(-1) were detected only in wine samples.     

The long-term environmental behaviour of strontium and barium released from former mine workings in the granites of the Sunart region of Scotland, UK

The concentrations of strontium and barium have been measured in water, sediment and the shells of mussels (Mytilus edulis) from a river system in the Sunart region of Scotland, UK. The aim was to establish the fate and mobility of these elements, which are slowly being released from old mine workings on the Strontian granites. Enhanced strontium (1500-2000 microg l(-1) and 250-290 microg l(-1)) and barium concentrations (316 microg l(-1) and 83 microg l(-1)) were found in the waters originating from the two mine drains studied. Both element were also found at significant levels in the river sediments taken from the vicinity of each drainage site (Sr: 225 microg g(-1) and 120-125 microg g(-1); Ba: 1380 microg g(-1) and 126-170 microg g(-1)). The data suggests that the sediments are acting as a reservoir for these group II cations from where they become distributed throughout the river system. Strontium is found to be incorporated into the shells (3.16-3.46 microg g(-1)) and pearls (3.57 microg g(-1)) of the blue mussel, located at the estuarine margin some 10 km downstream, at values close to the maximum expected (3.3% by weight of the calcium content). The study presents a view of the fate of barium and strontium in a river system over a prolonged period of time. As such it provides valuable information for studies that seek to model the impact of the accidental release of barium and strontium (including the important radionuclide 90Sr) into the environment.     

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.