Ultra-structural changes in the reproductive system of overwintering females of Acartia longiremis

As the only member of its genus, and along with only a few other marine copepod species, Acartia longiremis Lilljeborg overwinters as adult females in "active diapause" in the plankton. This study describes the changes in ultra-structure of the resting reproductive system from August to January, and evidence for fertilization in overwintering North Norwegian A. longiremis. Gonads in overwintering individuals remain in an undifferentiated state from September to January, i.e. without oocyte development or oocyte migration into the oviduct and its diverticulae. Lipid stores in close association with the reproductive system appear to be utilized for the development of primary oocytes after the overwintering period.     

Optimisation and use of tandem-in-time mass spectrometry in comparison with immunoassay and HRGC/HRMS for PCDD/F screening

Rapid screening of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans using quadrupole ion storage tandem-in-time mass spectrometry (QISTMS) conjointly with polyclonal antibody immunoassay has been considered. The optimisation of the fragmentation of the parent ion in the trap has been completed. The analysis of fly ashes from a municipal waste incinerator contaminated at different levels has then been realised. Results obtained using QISTMS, HRMS and immunoassay are compared.     

Enhanced transport of pesticides in a field trial with treated sewage sludge

This study was designed to provide high-density data on spatial distribution of three herbicides with different physiochemical characteristics in a sludge-amended and non-amended control field over the course of an irrigation season. The field experiment was carried out on a sandy loam Hamra Red Mediterranean soil (Rhodoxeralf) at Bet Dagan, Israel. After a single 50 mm irrigation event, the mean centers of mass (COM) in the control field were at 15.6, 14.9, and 17 cm for bromacil, atrazine and terbuthylazine, respectively; in the sludge-amended field, mean COMs were at 28.8, 31.2, and 34.1 cm, respectively. After 500 mm of irrigation in the control field, the COM depth distribution of the three pesticides was inversely correlated with octanol-water (Kow) distribution coefficients and soil sorption coefficients (Koc), and positively correlated with aqueous solubilities. After 500 mm irrigation in the sludge-amended field, the mean terbuthylazine COM was at 19.8 cm versus 13.8 cm for the control field, demonstrating a sustained enhanced effect on terbuthylazine transport. Downward transport of atrazine was also enhanced by sludge amendment, albeit less than terbuthylazine. Bromacil was preferentially accumulated in the upper soil layers of the sludge-amended field as compared with the control field after 500 mm irrigation. The enhanced transport of all three pesticides in the sludge-amended field after a single irrigation event is attributed to development of preferential flow pathways around hydrophobic clods of sludge. Enhanced transport of terbuthylazine, and to a lesser extent, atrazine, throughout the irrigation season, is attributed to their transport as complexes with dissolved, colloidal and suspended organic matter derived from sludge degradation.     

Hydroxyl radical scavenging role of chloride and bicarbonate ions in the H2O2/UV process

Simultaneous effect of inorganic anions, such as chloride and bicarbonate ions, on the scavenging of hydroxyl radicals (HO*) in the H2O2/UV process is the focus of this paper. The model compound of n-chlorobutane (BuCl) was used as the probe of HO*. By changing the pH conditions (2-9) and the concentrations of NaCl (0.25-2500 mM) and NaHCO3 (25 mM), the variation of HO* concentrations and the rate of H2O2 decomposition were compared. In general, the BuCl and H2O2 follow closely the first-order reaction within the first 10 and 40 min, respectively. In the presence of chloride alone at the pH range of 2-6, the HO* concentration in the reaction mixture increases with the increase of pH, and the HO* concentration at pH = 6 is 100 times of that at pH = 2. Including bicarbonate species in the solution, the peak HO* concentration was found at a certain pH, which shifts from 4, 5, to 5-7, as the molar ratios of chloride/bicarbonate species increase from 1 to 100. In addition, without bicarbonate species HO* concentration decreases significantly with increasing chloride concentration but remained rather unchanged beyond 1250 mM. In contrast, the HO* scavenging in the presence of bicarbonate species became relatively significant only when the chloride concentration reached beyond 250 mM. Throughout all experiments of different water quality conditions, the H2O2 decomposition rate remains rather unchanged.     

Genotoxic damage in free-living Algerian mouse (Mus spretus) after the Coto Doñana ecological disaster

The Do?ana National Park (Spain), one of the most important wildlife sites in the West of Europe, was affected (25 April 1998) by the spill of acidic waste rich in toxic metals (mainly zinc, lead, copper, etc.), arsenic and aromatic amines from the Aznalcollar mine accident. Micronuclei test with May Grunwald-Giemsa and with CREST-antikinetocore staining using DAPI as counter-staining were performed on peripheral blood erythrocytes from Algerian mice to evaluate genotoxic damage. Animals were collected in four locations each differently affected by the disaster. Higher frequencies of micronuclei and CREST-positive micronuclei were observed in the sites, which were reached by toxic sludge and contaminated water in comparison with those located within the park. The results obtained applying the two methods indicate that DAPI staining is more sensitive in detecting micronuclei. Genotoxic biomonitoring should be further carried out in the area to control the mutagenetic level in natural populations.     

Seasonal aerosol sulfate trends for selected regions of the United States

Site and regional trends in seasonally averaged particle SO4(2-) concentrations were examined for a large portion of the United States using data collected by the CASTNet air monitoring network. Trends were analyzed for overlapping periods of 1988-1999 and 1992-1999. The largest absolute SO4(2-) decreases--approximately -0.4 microg/m3/yr--between 1988 and 1999 occurred in summer for sites in the Ohio River Valley and areas to the east. Generally, the largest SO4(2-) reductions were found for summer, but larger relative reductions often occurred for spring and autumn. Sulfate changes during 1992-1999 were quite different from those found for 1988-1999 and were not entirely consistent with changes in SO2 emissions. In some locations, the 1992-1999 period saw smaller declines in SO4(2-), while in other places seasonal SO4(2-) actually increased. Increases were mostly confined to summer and autumn across the southern and southwestern states. Multivariate analysis of ambient sulfur levels, by region, versus SO2 emissions reveals that annual emissions are associated with more than 80% of the variance in seasonal sulfur (SO2 and SO4(2-)) in more than three-quarters of the cases examined. The weakest associations were found for the southeastern United States.     

Photodegradation of Pyrimethanil induced by iron(III) in aqueous solutions

In this study an abiotic process was suggested to evaluate the behaviour of Pyrimethanil (antibotrytic fungicide) in real matrices. This process consists of a photodegradation of the fungicide carried out in the presence of iron(III) in three types of buffer; acetate, phosphate and citrate. The experimental results show that the nature of buffered solutions influences both the rate of disappearance of Pyrimethanil and, in the case of citrate, also the kind of by-products formed during the photodegradation process. For each case examined, the breakdown products were identified by using liquid chromatography (LC) or gas chromatography (GC), coupled with mass spectrometry (MS). The degradation pathways of the fungicide were proposed and the relative kinetic constants were evaluated. The abiotic photodegradation process shows the possibility of different pathways for Pyrimethanil degradation in environmental matrices such as the soil, plants and foodstuffs, where iron (free and/or bonded) is a natural component.     

Precaution,uncertainty and causation in environmental decisions

What measures of uncertainty and what causal analysis can improve the management of potentially severe, irreversible or dreaded environmental outcomes? Environmental choices show that policies intended to be precautionary (such as adding MTBE to petrol) can cause unanticipated harm (by mobilizing benzene, a known leukemogen, in the ground water). Many environmental law principles set the boundaries of what should be done but do not provide an operational construct to answer this question. Those principles, ranging from the precautionary principle to protecting human health from a significant risk of material health impairment, do not explain how to make environmental management choices when incomplete, inconsistent and complex scientific evidence characterizes potentially adverse environmental outcomes. Rather, they pass the task to lower jurisdictions such as agencies or authorities. To achieve the goals of the principle, those who draft it must deal with scientific casual conjectures, partial knowledge and variable data. In this paper we specifically deal with the qualitative and quantitative aspects of the European Union's (EU) explanation of consistency and on the examination of scientific developments relevant to variability and uncertain data and causation. Managing hazards under the precautionary principle requires inductive, empirical methods of assessment. However, acting on a scientific conjecture can also be socially unfair, costly, and detrimental when applied to complex environmental choices. We describe a constructive framework rationally to meet the command of the precautionary principle using alternative measures of uncertainty and recent statistical methods of causal analysis. These measures and methods can bridge the gap between conjectured future irreversible or severe harm and scant scientific evidence, thus leading to more confident and resilient social choices. We review two sets of measures and computational systems to deal with uncertainty and link them to causation through inductive empirical methods such as Bayesian Networks. We conclude that primary legislation concerned with large uncertainties and potential severe or dreaded environmental outcomes can produce accurate and efficient choices. To do so, primary legislation should specifically indicate what measures can represent uncertainty and how to deal with uncertain causation thus providing guidance to an agency's rulemaking or to an authority's writing secondary legislation. A corollary conclusion with legal, scientific and probabilistic implications concerns how to update past information when the state of information increases because a failure to update can result in regretting past choices. Elected legislators have the democratic mandate to formulate precautionary principles and are accountable. To preserve that mandate, imbedding formal methods to represent uncertainty in the statutory language of the precautionary principle enhances subsequent judicial review of legislative actions. The framework that we propose also reduces the Balkanized views and interpretations of probabilities, possibilities, likelihood and uncertainty that exists in environmental decision-making.     

Effects of 17alpha-ethinylestradiol on the reproduction of the cladoceran species Ceriodaphnia reticulata and Sida crystallina

Single-species tests allow the assessment of chronical effects of endocrine disruptors on organisms under laboratory conditions. In the current study, three-generation tests with Ceriodaphnia reticulata and Sida crystallina were carried out to examine the influence of the synthetic hormone 17alpha-ethinylestradiol (EE) on the reproduction of these cladoceran species. For each species, six different concentrations (10-500 microg/l EE) and two controls were tested with eight replicates for a duration of 4 weeks. The test was initiated by transferring one neonate individual into a test vessel which was incubated under standardized conditions. Every 2 days, the medium was renewed and life history parameters such as survivorship of the adults and juveniles, clutch size, first appearance and number of produced offspring were investigated. Acute toxicity tests showed that C. reticulata (EC50 (24 h) 1814 microg/l) was more sensitive towards the substance compared to S. crystallina (EC50 (24 h) >4100 microg/l). The juvenile phase of S. crystallina was significantly shorter at concentrations above 100 microg/l EE. For C. reticulata, 17alpha-ethinylestradiol caused a higher mortality of the newly hatched juveniles at EE concentrations above 200 microg/l. No effects were found for mortality of adult animals, birth rate, number of juveniles per female and net reproduction rate of S. crystallina and C. reticulata. Thus, sublethal effects on parental generation exposed to EE lead to disturbances in reproduction and to affection of their offspring. Negative consequences for the population dynamic cannot be excluded, e.g. the decrease of a population.     

Hypersaline cyanobacterial mats as indicators of elevated tropical hurricane activity and associated climate change

The Atlantic hurricanes of 1999 caused widespread environmental damage throughout the Caribbean and US mid-Atlantic coastal regions. However, these storms also proved beneficial to certain microbial habitats; specifically, cyanobacteria-dominated mats. Modern mats represent the oldest known biological communities on earth, stromatolites. Contemporary mats are dominant biological communities in the hypersaline Bahamian lakes along the Atlantic hurricane track. We examined the impacts of varying levels of hypersalinity on 2 processes controlling mat growth, photosynthesis and nitrogen fixation, in Salt Pond, San Salvador Island, Bahamas. Hypersalinity (> 5 times seawater salinity) proved highly inhibitory to these processes. Freshwater input from Hurricane Floyd and other large storms alleviated this salt-inhibition. A predicted 10 to 40 year increase in Atlantic hurricane activity accompanied by more frequent "freshening" events will enhance mat productivity, CO2 sequestration and nutrient cycling. Cyanobacterial mats are sensitive short- and long-term indicators of climatic and ecological changes impacting these and other waterstressed environments.