Determination of sediment toxicity of Gorjak stream by bioassays in vitro

Brojna teško razgradiva organska zagađivala (eng. Persistent Organic Pollutants; POPs) poput polikloriranih dibenzo-p-dioksina i furana (PCDD/F), polikloriranih bifenila (PCB), polikloriranih naftalena (PCN) i policikličkih aromatskih ugljikovodika (PAH) izrazito su toksična. POP-sovi u okoliš najčešće dospijevaju industrijskim otpadnim vodama. Ispuštanjem nepročišćenih industrijskih otpadnih voda u potok Gorjak, tvrtke Pliva Hrvatska d.d. i Kvasac d.o.o. desetljećima predstavljaju problem za širu zajednicu. Cilj ovog istraživanja bio je odrediti razinu toksičnosti sedimenta potoka Gorjak pomoću dva biotesta: (1) testa kronične toksičnosti (inhibicija rasta zelene alge Scenedesmus subspicatus); te (2) EROD testa određivanja aktivnosti staničnog detoksikacijskog sustava oksidaza miješanih funkcija. Testom kronične toksičnosti mjerili smo razrjeđenja uzoraka sedimenta pri kojima je dosegnuta 50%-tna inhibicije rasta alge S. subspicatus (IC50) u odnosu na kontrolnu grupu. Odredili smo EC50 vrijednosti koje predstavljaju ekvivalentnu količinu sedimenta, te izračunali toksične jedinice (TJ) dobivene prema izrazu TJ = 100 / EC50. Izvođenjem EROD testa izračunali smo TCDD toksične ekvivalente (TCDD TEQ). Rezultati pokazuju visoku toksičnost sedimenata na svim lokacijama, uz izrazito visoke vrijednosti neposredno nakon ispusta industrijskih otpadnih voda spomenutih tvrtki.Numerous persistent organic pollutants (POPs), such as polychlorinated dibenzo-p-dioxins and furans (PCDD/F), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs) and polyaromatic hydrocarbons (PAHs) are highly toxic. POPs get into environment mostly by industrial wastewaters. By releasing untreated industrial wastewater into the Gorjak stream, Industries Pliva Hrvatska d.d. and Kvasac d.o.o. for decades represent a problem for local community. The purpose of this research was to determine ecotoxicity of Gorjak stream sediment samples, using two bioassays: (1) chronic toxicity test (growth inhibition test with green algae Scenedesmus subspicatus), and (2) EROD test for determination of the activity of the mixed function oxygenases cellular detoxification system. Using chronic toxicity test we measured sample dilutions at which 50% growth inhibion of the algae was achieved (IC50) in comparison to the control group. EC50 values representing corresponding amount of sediment were determined and toxicity units (TU) obtained recalculated by expression TU = 100 / EC50. For the EROD bioassay we calculated TCDD toxicity equivalents (TCDD TEQ). Results showed high sediment toxicity at each location, with the highest values determined at location closest to the wastewater outlet of the above mentioned industrial facilities

Determination of sediment toxicity of Gorjak stream by bioassays in vitro

Brojna teško razgradiva organska zagađivala (eng. Persistent Organic Pollutants; POPs) poput polikloriranih dibenzo-p-dioksina i furana (PCDD/F), polikloriranih bifenila (PCB), polikloriranih naftalena (PCN) i policikličkih aromatskih ugljikovodika (PAH) izrazito su toksična. POP-sovi u okoliš najčešće dospijevaju industrijskim otpadnim vodama. Ispuštanjem nepročišćenih industrijskih otpadnih voda u potok Gorjak, tvrtke Pliva Hrvatska d.d. i Kvasac d.o.o. desetljećima predstavljaju problem za širu zajednicu. Cilj ovog istraživanja bio je odrediti razinu toksičnosti sedimenta potoka Gorjak pomoću dva biotesta: (1) testa kronične toksičnosti (inhibicija rasta zelene alge Scenedesmus subspicatus); te (2) EROD testa određivanja aktivnosti staničnog detoksikacijskog sustava oksidaza miješanih funkcija. Testom kronične toksičnosti mjerili smo razrjeđenja uzoraka sedimenta pri kojima je dosegnuta 50%-tna inhibicije rasta alge S. subspicatus (IC50) u odnosu na kontrolnu grupu. Odredili smo EC50 vrijednosti koje predstavljaju ekvivalentnu količinu sedimenta, te izračunali toksične jedinice (TJ) dobivene prema izrazu TJ = 100 / EC50. Izvođenjem EROD testa izračunali smo TCDD toksične ekvivalente (TCDD TEQ). Rezultati pokazuju visoku toksičnost sedimenata na svim lokacijama, uz izrazito visoke vrijednosti neposredno nakon ispusta industrijskih otpadnih voda spomenutih tvrtki.Numerous persistent organic pollutants (POPs), such as polychlorinated dibenzo-p-dioxins and furans (PCDD/F), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs) and polyaromatic hydrocarbons (PAHs) are highly toxic. POPs get into environment mostly by industrial wastewaters. By releasing untreated industrial wastewater into the Gorjak stream, Industries Pliva Hrvatska d.d. and Kvasac d.o.o. for decades represent a problem for local community. The purpose of this research was to determine ecotoxicity of Gorjak stream sediment samples, using two bioassays: (1) chronic toxicity test (growth inhibition test with green algae Scenedesmus subspicatus), and (2) EROD test for determination of the activity of the mixed function oxygenases cellular detoxification system. Using chronic toxicity test we measured sample dilutions at which 50% growth inhibion of the algae was achieved (IC50) in comparison to the control group. EC50 values representing corresponding amount of sediment were determined and toxicity units (TU) obtained recalculated by expression TU = 100 / EC50. For the EROD bioassay we calculated TCDD toxicity equivalents (TCDD TEQ). Results showed high sediment toxicity at each location, with the highest values determined at location closest to the wastewater outlet of the above mentioned industrial facilities

Time for a Nappy Change: controls affecting families’ nappy choices

Lifecycle assessments suggest that modern cloth nappies have fewer environmental impacts than their disposablecounterparts in terms of GHG, plastic and landfill (UNEP 2021). However, despite these apparent environmentalbenefits consumers still use predominantly disposable nappies. This paper will use theories of plannedbehaviour to explore the differences in perceived and actual behaviours between disposable and cloth nappyusers. A self-selecting web-based survey was used to recruit participants with children up to the age of fiveand explore their decision-making in this regard. The findings of the survey reveal that disposable nappy usersare more likely to prioritise convenience and to cite additional laundry loads as the main reasons for not usingcloth nappies. This is despite tending to have the necessary infrastructure (such as disposable income, spaceand washing facilities) to enable them to do so. This indicates that the perceptions of home-laundered clothnappies as inconvenient makes families more likely to opt for disposable nappies. Whilst cloth nappies weregenerally assumed to be more environmentally friendly and aesthetically pleasing by all parents irrespectiveof their choices, this was not enough to overcome the convenience and ease of use for the majority of participants.This study concludes that many disposable nappy users select disposable nappies with the assumptionthat they are easier and more convenient when this may not be the case. The implication of this study is thatinterventions which improve the convenience of cloth nappies and the perception of ease of use will encouragegreater uptake of cloth nappies.References.UNEP. (2021) Recommendations from Life Cycle Assessments Single-use nappies and their alternatives hostedby. United Nations Environment Programme

Physical-chemical treatment of landfill leachate : technological performance, spectral characterization and cost estimations

The generation of landfill leachate is a significant result of landfilling. Because of the high concentrations of pollutants in leachate, disposal of raw or insufficiently treated landfill leachate can cause harm to the environment. Biological processes are inefficient for the treatment of stabilized landfill leachate given the presence of recalcitrant organic compounds and low leachate biodegradability. As such, post-treatment is required to meet discharge standards. Therefore, this PhD thesis focused on the (post)-treatment of raw and biologically treated landfill leachate using four physical-chemical processes, i.e. ozonation, coagulation-flocculation, granular activated carbon (GAC) adsorption, and ion exchange. The aim was obtaining an optimized and cost effective integrated leachate treatment train. The research also used spectral and chemometric techniques to characterize dissolved organic matter (DOM) components in landfill leachate and to monitor how they are removed during treatment. The results show that (post)-treatment of raw and biologically treated leachate with a single physical-chemical step is inefficient as the environmental discharge standards are not met. However, combining coagulation-flocculation or ozonation with GAC adsorption significantly reduces the pollutant concentrations making it possible to meet the discharge standards. Spectral and chemometric analysis show that coagulation as a pre-treatment step removes high molecular weight humic compounds that would otherwise clog the GAC adsorption sites, and that GAC unselectively removes DOM components hereby improving the overall performance. Ion exchange can be used to recover ammonium from the raw landfill leachate with complete removal. Overall, (post)-treatment of raw and biologically treated leachate with coagulation-flocculation + GAC + ion exchange and coagulation-flocculation + GAC, respectively, are shown to be more efficient and cost effective than a treatment train without coagulation-flocculation pre-treatment