Biochemical effects of clomazone herbicide on piava (Leporinus obtusidens)

This study aims to verify the effects of the clomazone concentration used in rice fields on acetylcholinesterase (AChE), thiobarbituric acid reactive substances (TBARS), protein carbonyl and catalase activity in tissues of piava (Leporinus obtusidens). LC(50)-96h was 5.0 mg L(-1) and the fish were exposed to 1/10 of LC(50)-96 h: 0.5 mg L(-1) of clomazone for 96 and 192h. The same parameters were also assayed after a recovery period of 192 h in clean water. AChE activity was reduced only in the brain and heart of fish exposed for 96 h. AChE activity was decreased in the brain, muscle and heart tissues after 192 h of exposure. After 192 h of recovery period, AChE activity remained diminished in brain and muscle and showed a decrease in eye. However, after 192 h of recovery, AChE activity in heart was recovered. Fish showed increased TBARS levels in brain at all experimental periods. TBARS levels decreased in liver and muscle tissues after 192 h of exposure. The increase in muscle TBARS persisted in fish transferred to clean water. Protein carbonyl in the liver was increased in all periods studied including the recovery period. Catalase activity was reduced during all periods. The present study demonstrates the occurrence of disorders in AChE, TBARS, protein carbonyl and catalase activity in piava. The results also show changes in fish after exposure to an environmentally relevant concentration of clomazone. Most effects observed persisted after the recovery period. Thus, these parameters may be used to monitor clomazone toxicity in fish.     

Seasonal variation of extracellular enzymatic activity (EEA) and its influence on metal speciation in a polluted salt marsh

The influence of salt marsh sediment extracellular enzymatic activity (EEA) on metal fractions and organic matter cycling was evaluated on a seasonal basis, in order to study the relation between organic matter cycles and the associated metal species. Metals in the rhizosediment of Halimione portulacoides were fractioned according to the Tessier's scheme and showed a similar pattern regarding the organic-bound fraction, being always high in Autumn, matching the season when organic matter presented higher values. Both organic-bound and residual fractions were always dominant, being the seasonal variations due to interchanges between these two fractions. Phenol oxidase and beta-N-acetylglucosaminidase had higher activities during the Spring and Summer, contrarily to peroxidase which had higher activity during Winter. Protease showed high activities in both Spring and Winter. These different periods of high organic matter hydrolysis caused two periods of organic metal bound decrease. Sulphatase peaks (Spring and Winter) matched the depletion of exchangeable metal forms, probably due to sulphides formation and consequent mobilization. This showed an interaction between several microbial activities affecting metal speciation.     

Alteration of potential harmful elements levels in sediments and biota from the central Mediterranean Sea (Aeolian Archipelago) following an episode of intense volcanic activity

In this paper levels of four (Hg, Cd, Pb, As) potential harmful elements (PHE) were measured in three different environmental matrices (sediments, macroalgae and fishes) from the Aeolian Archipelago and control areas both after 1 and 10 months from a volcanic activity of particular relevance occurred at the end of October 2002. Results were analysed on a multivariate statistical basis with the aim to evaluate: (I) general levels of pollution and increase of PHE due to the event; (II) differences observed among tested matrices in the time of recovery after the occurrence of the critical event; (III) the biological enrichment of PHE along the trophic web produced by the geological event. Results evidenced that volcanic emissions could represent a local source of particular relevance able to determine great enrichments of considered PHE in sediments and biological species. After 10 months from the event, levels in sediments and macroalgae notably decreased, whereas fish species evidenced an increase, principally related to the bioaccumulation phenomena. On the basis of the biological enrichment factors (BEF), major enrichments were evidenced after 1 month whereas, after 10 months, were recorded values reliable to an incomplete recovery. Concerning Cd, the BEF higher levels reported for the species Serranus cabrilla was probably related both to the diet and to the specific detoxification rates of this species.     

Atmospheric composition change research: Time to go post-normal?

For more than two decades a number of frameworks for scientific knowledge production are being proposed by science and technology researchers. They all advocate an extended involvement of non-specialists, in particular when it comes to knowledge production applicable to practical societal problems. We look to what extent these new frameworks have taken ground within a particular research community: the ACCENT Network of Excellence which coordinates European atmospheric chemistry and physics research applicable to air pollution and climate change. We did so by stimulating a debate through a “blog”, a survey and in-depth interviews with ACCENT scientists about the interaction between science, policy making and civil society, to which a great deal of ACCENT member contributed in writing or verbally. Most of them had interactions with policy makers and/or the general public, and they generally believe that interactions with spheres other than the scientific are needed. While such interactions give personal insight and satisfaction, they seem to have little impact on the goals and the practice of the scientific work itself. Extended frameworks of science production that go beyond the disciplinary mode seem to emerge at the level of individual scientists, yet they still need to find their way to the level of scientific project management. In this paper we discuss the justifications and barriers to implement a higher degree of extended knowledge integration in applied science projects such as ACCENT. It is felt that the community of atmospheric chemists and physicists is mature for such an implementation and recommendations are given to help and make this happen.     

Biochemical effects of acetaminophen in aquatic species: edible clams Venerupis decussata and Venerupis philippinarum

Acetaminophen (paracetamol) is one of the most used pharmaceutical drugs, due to its antipyretic and analgesic properties that turn it into a primary choice in varied pathologies and conditions. However, and despite its massive use, acetaminophen is not exempt of adverse effects, especially when administered in over dosage, which are related to the formation of toxic metabolites by oxidative pathways. It is thus possible to observe that toxicity caused by acetaminophen is usually mediated by reactive oxygen species and can result in multiple effects, ranging from protein denaturation to lipid peroxidation and DNA damage. The occurrence of acetaminophen has been reported in the aquatic environment, being important to address the potential exertion of toxic effects on nontarget environmentally exposed organisms. The present study intended to characterize the effects of acute acetaminophen exposure on physiological traits (antioxidant defense, oxidative damage) of two species of bivalves, namely, the edible clams Venerupis decussata and Venerupis philippinarum. Results showed a significant increase in all oxidative stress biomarkers, evidencing the bioactivation of acetaminophen into a deleterious prooxidant, triggering the onset of deleterious effects. Furthermore, strong interspecific differences were observed among responses of the two tested species, which was a major issue due to intrinsic ecological implications when one considers that both species share the same habitat.     

Characterization of humic-rich hydrocolloids and their metal species by means of competing ligand and metal exchange--an on-site approach

An improved on-site characterization of humic-rich hydrocolloids and their metal species in aquatic environments was the goal of the present approach. Both ligand exchange with extreme chelators (diethylenetetraaminepentaacetic acid (DTPA), ethylendiaminetetraacetic acid (EDTA)) and metal exchange with strongly competitive cations (Cu(II) were used on-site to characterize the conditional stability and availability of colloidal metal species in a humic-rich German bogwater lake (Venner Moor, Münsterland). A mobile time-controlled tangential-flow ultrafiltration technique (cut-off: 1 kDa) was applied to differentiate operationally between colloidal metal species and free metal ions, respectively. DOC (dissolved organic carbon) and metal determinations were carried out off-site using a home-built carbon analyzer and conventional ICP-OES (inductively-coupled plasma-optical emission spectrometry), respectively. From the metal exchange equilibria obtained on-site the kinetic and thermodynamic stability of the original metal species (Fe, Mn, Zn) could be characterized. Conditional exchange constants Kex obtained from aquatic metal species and competitive Cu(II) ions follow the order Mn > Zn > > Fe. Obviously, Mn and Zn bound to humic-rich hydrocolloids are very strongly competed by Cu(II) ions, in contrast to Fe which is scarcely exchangeable. The exchange of aquatic metal species (e.g. Fe) by DTPA/EDTA exhibited relatively slow kinetics but rather high metal availabilities, in contrast to their Cu(II) exchange.     

Environmental exposure of pharmaceuticals and musk fragrances in the Somes River before and after upgrading the municipal wastewater treatment plant Cluj-Napoca,Romania

Background, aim, and scope

Pharmaceutically active substances are a class of emerging contaminants, which has led to increasing concern about potential environmental risks. After excretion, substantial amounts of unchanged pharmaceuticals and their metabolites are discharged into domestic wastewaters. The absence of data on the environmental exposure in Eastern Europe is significant, since use patterns and volumes differ from country to country. In Romania, the majority of wastewater, from highly populated cities and industrial complex zones, is still discharged into surface waters without proper treatment or after inefficient treatment. In respect to this, it is important to determine the environmental occurrence and behavior of pharmaceuticals and personal care products (PPCPs) in wastewaters and surface waters. The objective of the present study was to investigate the occurrence of selected PPCPs during the transport in the Somes River by mass flow analysis before and after upgrading a municipal wastewater treatment plant (WWTP) in Cluj-Napoca, which serves 350,000 inhabitants and is the largest plant discharging into the Somes River. The concentrations of PPCPs at Cluj-Napoca can be correlated with the high population and a high number of hospitals located in the catchment area leading to higher mass flows. The results of this study are expected to provide information, with respect to the Romanian conditions, for environmental scientists, WWTP operators, and legal authorities. The data should support the improvement of existing WWTPs and implementation of new ones where necessary and, therefore, minimize the input of contaminants into ambient waters.

Materials and methods

The PPCPs were selected on the basis of consumption at the regional scale, reported aquatic toxicity, and the suitability of the gas chromatography/mass spectrometry (GC/MS) method for the determination of the compounds at trace levels. The studied PPCPs, caffeine (stimulant), carbamazepine (antiepileptic), pentoxifylline (anticoagulant), cyclophosphamide (cytostatic), ibuprofen (analgesic), and galaxolide (musk fragrance), were determined in samples of the Somes River. The analytes were enriched by solid-phase extraction and subsequently determined by GC/MS. Caffeine, pentoxifylline, and galaxolide were determined underivatized, whereas the acidic pharmaceuticals carbamazepine, cyclophosphamide, and ibuprofen were determined after derivatization with N-methyl-N-(trimethylsilyl)-trifluoroacetamide.

Results and discussion

The concentrations in the Somes River varied from below 10 ng/L up to 10 μg/L. A substantial decrease of the exposure in the Somes River could be observed due to the upgrade of the municipal WWTP in Cluj-Napoca. The loads in the river stretch between Cluj-Napoca and Dej (Somes Mic) varied strongly: caffeine (400–2,000 g/day), carbamazepine (78–213 g/day), galaxolide (140–684 g/day), ibuprofen (84–108 g/day). After the upgrade of the WWTP Cluj-Napoca, the concentrations in the Somes of caffeine, pentoxifylline, cyclophosphamide, galaxolide, and tonalide were significantly reduced (over 75%). One might be cautious comparing both studies because the relative efficiency of the WWTP’s removal of PPCP was not evaluated. However, the significantly lower concentrations of most compounds after the upgrade of the WWTP Cluj-Napoca allow one to infer that the technical measures at the source substantially reduced inputs of contaminants to the receiving river. Dej loads of the poorly biodegradable substance carbamazepine increased by a factor of 2–3 as a result of wastewater discharges into the river. The disproportionate increase in caffeine loads by a factor of 4 below Cluj-Napoca indicates inputs of untreated wastewater from the Somes Mare due to the discharge of untreated wastewater derived from Bistrita, Nasaud, and Beclean (115,000 inhabitants).

Conclusions

The relative contribution of treated and untreated wastewater in surface water might be assessed by measuring chemical markers. Recalcitrant pharmaceuticals like carbamazepine are suitable as chemical markers for estimating the relative contribution of wastewater in surface water. The easily degradable caffeine might be a good indicator for raw sewage and hardly treated wastewaters.

Recommendations and perspectives

Municipal WWTPs have the potential of a significant contribution in reducing the load of contaminants to ambient waters. The efficiency of the wastewater treatment in Cluj-Napoca improved considerably after the upgrade of the WWTP. Therefore, it is crucial that several WWTPs must be implemented or improved in the Somes Valley Watershed in order to reduce the discharge of contaminants in the Somes River from these point sources.