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A systematic tool to assess the Carbon Footprint (CF) and Water Footprint (WF) of pork production companies was developed and applied to representative Catalan companies. To do so, a cradle-to-gate environmental assessment was carried out by means of the LCA methodology, taking into account all the stages involved in the pork chain, from feed production to the processing of final products, ready for distribution. In this approach, the environmental results are reported based on eight different functional units (FUs) according to the main pork products obtained. With the aim of ensuring the reliability of the results and facilitating the comparison with other available reports, the Product Category Rules (PCR) for Catalan pork sector were also defined as a basis for calculations. The characterization results show fodder production as the main contributor to the global environmental burdens, with contributions higher than 76% regardless the environmental indicator or the life cycle stage considered, which is in agreement with other published data. In contrast, the results in terms of CF and WF lay above the range of values reported elsewhere. However, major discrepancies are mainly due to the differences in the co-products allocation criteria. In this sense, economic/physical allocation and/or system expansion have been mostly considered in literature. In contrast, no allocation was considered appropriate in this study, according to the characteristics of the industries and products under assessment; thus, the major impacts fall on the main product, which derives on comparatively higher environmental burdens. Finally, due to the relevance of fodder production in the overall impact assessment results, strategies to reduce greenhouse gases (GHG) emissions as well as water use associated to this stage were proposed in the pork supply chain.
Assuntos
Ração Animal/análise , Criação de Animais Domésticos/métodos , Pegada de Carbono , Tecnologia de Alimentos/métodos , Produtos da Carne/análise , Suínos/crescimento & desenvolvimento , Poluição da Água , Criação de Animais Domésticos/estatística & dados numéricos , Animais , Pegada de Carbono/normas , Pegada de Carbono/estatística & dados numéricos , Conservação dos Recursos Naturais , Tecnologia de Alimentos/estatística & dados numéricos , Efeito Estufa/estatística & dados numéricos , Modelos Estatísticos , Reprodutibilidade dos Testes , Espanha , Poluição da Água/análise , Poluição da Água/estatística & dados numéricosRESUMO
Bacterial exopolysaccharides (EPS) are extracellular polymer-based substances recently defined as potential plant biostimulants, as they can increase nutrient uptake, water retention, and resistance to abiotic stress. As sugar-based substances, the bacteria producing them need to grow in a sugar-rich substrate. Hence, some agri-food by-products could be used as suitable carbon sources for EPS production as a cost-effective and more sustainable alternative to conventional substrates. Thus, this study aimed to produce EPS from specific bacterial strains through solid-state fermentation (SSF) using agri-food waste as a low-cost substrate. Six residues and five bacterial strains were tested in a lab-scale SSF system. From the assessed substrate-strain combinations, Burkholderia cepacia with ginger juice waste (GJW) resulted in the most promising considering several process parameters (EPS production, cumulative oxygen consumption, biomass growth, reducing sugars consumption). Also, dynamic monitoring of the system allowed for establishing 5 days as a suitable fermentation time. Then, using response surface methodology (Box-Behnken design), the process was optimised based on airflow rate (AF), inoculum size (IS), and micronutrient concentration (MN). In this stage, the best conditions found were at 0.049 (± 0.014) L h-1 per gram of dry matter (DM) for AF, 8.4 (± 0.9) E + 09 CFU g-1 DM for IS, and 0.07 (± 0.01) mL g-1 DM for MN, reaching up to 71.1 (± 3.2) mg crude EPS g-1 DM. Results show the potential of this approach to provide a new perspective on the value chain for the agri-food industry by introducing it to a circular economy framework.
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The overuse and misuse of antibiotics have accelerated the selection of antibiotic-resistant bacteria, significantly impacting human, animal, and environmental health. As aquatic environments are vulnerable to antibiotic resistance, suitable management practices should be adopted to tackle this phenomenon. Here we show an effective, nature-based solution for reducing antibiotic resistance from actual wastewater. We utilize a bioreactor that relies on benthic (biofilms) and planktonic microbial communities to treat secondary effluent from a small urban wastewater treatment plant (<10,000 population equivalent). This treated effluent is eventually released into the local aquatic ecosystem. We observe high removal efficiency for genes that provide resistance to commonly used antibiotic families, as well as for mobile genetic elements that could potentially aid in their spread. Importantly, we notice a buildup of sulfonamide (sul1 and sul2) and tetracycline (tet(C), tet(G), and tetR) resistance genes specifically in biofilms. This advancement marks the initial step in considering this bioreactor as a nature-based, cost-effective tertiary treatment option for small UWWTPs facing antibiotic resistance challenges.
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The ever-increasing demand for phosphorus fertilisers for securing global food production, coupled with finite phosphate rock reserves, is one of the emerging problems in the world. Indeed, phosphate rock is listed as an EU critical raw material, triggering attention to find an alternative source to substitute the use of this limited resource. Cheese whey, characterized by a high content of organic matter and phosphorus, represents a promising feedstock for phosphorus recovery and recycling. An innovative application of a membrane system coupled with freeze concentration was assessed to recover phosphorus from cheese whey. The performances of a microfiltration membrane (0.2 µm) and an ultrafiltration (200 kDa) membrane were evaluated and optimized under different transmembrane pressures and crossflow velocities. Once the optimal operating conditions were determined, a pre-treatment including lactic acid acidification and centrifugation was applied to increase the permeate recovery. Finally, the efficiency of progressive freeze concentration for the treatment of the permeate obtained from the optimum conditions (UF 200 kDa with TMP of 3 bar, CFV of 1 m/s and lactic acid acidification) was evaluated at specific operating conditions (-5 °C and 600 rpm of stirring speed). Finally, 70% of phosphorus could be recovered from cheese whey using the coupled technology of the membrane system and freeze concentration. A phosphorus-rich product was obtained with high agronomic value, which constitutes a further step towards establishing a broader circular economy framework.
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To evaluate the effects of hydrological variability on pesticide dissipation capacity by stream biofilms, we conducted a microcosm study. We exposed biofilms to short and frequent droughts (daily frequency), long and less frequent droughts (weekly frequency) and permanently immersed controls, prior to test their capacities to dissipate a cocktail of pesticides composed of tebuconazole, terbuthylazine, imidacloprid, glyphosate and its metabolite aminomethylphosphonic acid. A range of structural and functional descriptors of biofilms (algal and bacterial biomass, extracellular polymeric matrix (EPS) concentration, microbial respiration, phosphorus uptake and community-level physiological profiles) were measured to assess drought effects. In addition, various parameters were measured to characterise the dynamics of pesticide dissipation by biofilms in the different hydrological treatments (% dissipation, peak asymmetry, bioconcentration factor, among others). Results showed higher pesticide dissipation rates in biofilms exposed to short and frequent droughts, despite of their lower biomass and EPS concentration, compared to biofilms in immersed controls or exposed to long and less frequent droughts. High accumulation of hydrophobic pesticides (tebuconazole and terbuthylazine) was measured in biofilms despite the short exposure time (few minutes) in our open-flow microcosm approach. This research demonstrated the stream biofilms capacity to adsorb hydrophobic pesticides even in stressed drought environments.
Assuntos
Praguicidas , Rios , Biofilmes , Transporte Biológico , Biomassa , Praguicidas/farmacologiaRESUMO
The rapid growth of the livestock sector in some areas of Europe has caused an imbalance between the generation of livestock manure and the availability of agricultural soil for its direct application as a fertilizer. Since the transport of pig slurry to other areas with nutrient-deficient soils is costly from an economic point of view due to its high water content, the application of new technologies for the concentration of this waste is considered key for reducing management costs. Consequently, the main objective of this study was to demonstrate the potential of vibratory shear enhanced processing (VSEP) operated with reverse osmosis membranes to recover nutrients from the liquid fractions of pig slurry (LF-pig slurry) and digestate (LF-digestate) and obtain concentrated fertilizing products. Use of the VSEP unit permitted reductions in the water contents of the LF-pig slurry and LF-digestate, around 77% and 67%, respectively. Both VSEP concentrates were characterized by their significant nutrient contents and showed a nitrogen fertilizer replacement value similar to that of mineral fertilizer as demonstrated in a barley crop pot-test, although the salinity of the digestate concentrate was identified as a key limitation, negatively impacting the agronomic yield of the test crop.
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Potash abandoned mines cause severe environmental damage to their bordering environment, with significant impacts on freshwater ecosystems mostly through uncontrolled discharge of hypersaline effluents. This study aimed to evaluate the ecological impact caused by a hypersaline effluent from an abandoned potash mine (Menteroda, Germany) on freshwater biofilms and, specifically, on diatom communities. Biofilm from a pristine stream was exposed under controlled conditions in microcosms to a mining effluent (ME), and its structural (algal biomass, community composition, diatom metrics) and functional (photosynthetic activity, nutrient uptake) responses were evaluated over time and compared with unexposed biofilms used as control. Biofilm exposed to ME showed drastic functional responses after one day of exposure, with a significant decrease in photosynthetic efficiency and nutrient uptake, that were recovered over time. Biofilm exposed to ME showed a progressive increase in diatom metrics (abundance, density and growth rate) over time, compared to the control. However, a significant decrease in diatom species diversity, richness and cell size was also observed in biofilm exposed to ME. This study revealed that the ME affected the biofilm causing short-term functional responses, which were recovered simultaneously with a drastic diatom community structure shift.
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Biofilmes/efeitos dos fármacos , Misturas Complexas , Diatomáceas/efeitos dos fármacos , Água Doce/química , Mineração , Poluentes Químicos da Água/toxicidade , Biofilmes/crescimento & desenvolvimento , Biomassa , Diatomáceas/crescimento & desenvolvimento , Ecossistema , Água Doce/microbiologia , Alemanha , Microbiota/efeitos dos fármacos , Salinidade , Poluentes Químicos da Água/análiseRESUMO
In recent decades, human activity coupled with climate change has led to a deterioration in the quality of surface freshwater. This has been related to an increase in the appearance of algal blooms, which can produce organic compounds that can be toxic or can affect the organoleptic characteristics of the water, such as its taste and odor. Among these latter compounds is geosmin, a metabolite produced by certain cyanobacteria that confers an earthy taste to water and which can be detected by humans at very low concentrations (nanogram per liter). The difficulty and cost of both monitoring the presence of this compound and its treatment is a problem for drinking water treatment companies, as the appearance of geosmin affects consumer confidence in the quality of the drinking water they supply. In this field study, the evaluation of four sampling sites with different physicochemical conditions located in the upper part of the Ter River basin, a Mediterranean river located in Catalonia (NE Spain), has been carried out, with the aim of identifying the main triggers of geosmin episodes. The results, obtained from 1 year of sampling, have made it possible to find out that: (i) land uses with a higher percentage of agricultural and industrial activity are related to high nutrient conditions in river water, (ii) these higher nutrient concentrations favor the development of benthic cyanobacteria, (iii) in late winter-early spring, when these cyanobacteria are subjected to both an imbalance of the dissolved inorganic nitrogen and soluble reactive phosphorus ratio, guided by a phosphorus concentration increase, and to cold-mild temperatures close to 10°C, they produce and release geosmin, and (iv) 1-2 weeks after cyanobacteria reach a high relative presence in the whole biofilm, an increase in geosmin concentration in water is observed, probably associated with the cyanobacteria detachment from cobbles and consequent cell lysis. These results could serve as a guide for drinking water treatment companies, indicating under what conditions they can expect the appearance of geosmin episodes and implement the appropriate treatment before it reaches consumers' tap.
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Polyhydroxyalkanoates (PHAs) are polyesters of significant interest due to their biodegradability and properties similar to petroleum-derived plastics, as well as the fact that they can be produced from renewable sources such as by-product streams. In this study, brewer's spent grain (BSG), the main by-product of the brewing industry, was subjected to a set of physicochemical pretreatments and their effect on the release of reducing sugars (RS) was evaluated. The RS obtained were used as a substrate for further PHA production in Burkholderia cepacia, Bacillus cereus, and Cupriavidus necator in liquid cultures. Although some pretreatments proved efficient in releasing RS (acid-thermal pretreatment up to 42.1â¯gRS L-1 and 0.77â¯gRS g-1 dried BSG), the generation of inhibitors in such scenarios likely affected PHA production compared with the process run without pretreatment (direct enzymatic hydrolysis of BSG). Thus, the maximum PHA accumulation from BSG hydrolysates was found in the reference case with 0.31⯱â¯0.02â¯g PHA per g cell dried weight, corresponding to 1.13⯱â¯0.06â¯g L-1 and a PHA yield of 23⯱â¯1â¯mg g-1 BSG. It was also found that C. necator presented the highest PHA accumulation of the tested strains followed closely by B. cepacia, reaching their maxima at 48â¯h. Although BSG has been used as a source for other bioproducts, these results show the potential of this by-product as a no-cost raw material for producing PHAs in a waste valorization and circular economy scheme.
Assuntos
Bacillus cereus/metabolismo , Burkholderia cepacia/metabolismo , Cupriavidus necator/metabolismo , Grão Comestível/química , Poli-Hidroxialcanoatos/biossíntese , Grão Comestível/metabolismo , Poli-Hidroxialcanoatos/químicaRESUMO
The global increase of cyanobacterial blooms occurrence has been associated with the presence of compounds that generate earthy and musty odor in freshwater systems, among which geosmin stands out. The lack of information on the factors associated to geosmin production by benthic organisms has driven the development of this study, whose main goal is to determine the effects of nutrient concentration and DIN:SRP ratio on geosmin formation and release. The experiment was performed in 18 microcosms under controlled conditions for 21 days, using a natural biofilm suspension from Ter river (NE, Spain) to promote biofilm settlement. Six treatments were set crossing three DIN:SRP ratios (A = 4:1, B = 16:1 and C = 64:1) with two nutrient concentrations (Low and High). After 7 days of experiment, geosmin was detected in biofilm, being higher under high nutrient concentration and low DIN:SRP ratio conditions. In this treatment, geosmin in biofilm reached its maximum concentration at day 16 (3.8 ± 0.9 ng/mg), decreasing at the end of the experiment (21d) due to cyanobacteria detachment and geosmin release into the water (136 ± 6 ng/L). Overall, this experimental study showed that high nutrient concentration and low DIN:SRP ratio favored the Oscillatoria genus development within biofilm communities, generating the optimal conditions for geosmin production. The interaction between these two factors was demonstrated to be a potential driver of benthic geosmin production and release, and should be monitored and controlled in rivers exploited for drinking water purposes.
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Naftóis , Odorantes , Biofilmes , Nutrientes , Odorantes/análise , EspanhaRESUMO
Respiration indices are suggested in literature as the most suitable stability determination and are proposed as a biodegradability measure in this work. An improved dynamic respiration index methodology is described in this work. This methodology was applied to 58 samples of different types of waste including municipal solid wastes and wastewater sludge, both raw materials and samples collected in a mechanical-biological treatment plant at different stages of biodegradation. The information obtained allowed to establish a qualitative classification of wastes in three categories: highly biodegradable, moderately biodegradable, and wastes of low biodegradability. Results were analyzed in terms of long and short-term indices and index expression: dynamic respiration indices expressed as average oxygen uptake rate (mg O(2) g(-1) dry matter [DM] h(-1)) at 1 and 24 h of maximum activity (DRI(1h), DRI(24h)); and cumulative oxygen consumption in 24 h of maximum activity and 4 d (AT(24h), AT(4)). The statistical comparison of indices and wastes is also presented. Raw sludge presented the highest biodegradability followed by the organic fraction of municipal solid waste and anaerobically digested sludge. All indices correlated well but different correlations were found for the different wastes analyzed. The information in the dynamic respiration profile allows for the calculation of different indices that provide complementary information. The combined analysis of DRI(24h) and AT(4) is presented here as the best tool for biodegradable organic matter content characterization and process requirements estimation.
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Compostos Orgânicos/metabolismo , Oxigênio/metabolismo , Resíduos/análise , Biodegradação Ambiental , Consumo de OxigênioRESUMO
The fate and degradation of 28 multiple-class veterinary pharmaceuticals in an on-farm pig slurry treatment plant based on solid-liquid separation and a nitrification-denitrification (NDN) sequence batch reactor (SBR) were evaluated for the first time. The pharmaceuticals detected at the highest concentrations in raw pig slurries belonged to the group of tetracycline antibiotics. Fluoroquinolone, lincosamide and pleuromutilin antibiotics and other drugs such as flubendazole and flunixin were also frequently detected. After solid-liquid separation, target compounds were distributed in an average of 64% onto the liquid fraction. Pharmaceuticals distributed in this fraction were removed in an average of almost 50% after being treated in NDN-SBR. Lincomycin was the compound with the highest removal percentage, reaching 100% reduction, while tetracyclines and fluoroquinolones showed moderate removal percentages (50 and 40%, respectively). Regarding nitrogen removal, NDN-SBR reduced a 77% of the content of this nutrient in the liquid slurry fraction.
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Desnitrificação , Nitrificação , Animais , Reatores Biológicos , Fazendas , Nitrogênio , SuínosRESUMO
The biological stability determines the extent to which readily biodegradable organic matter has decomposed. In this work, a massive estimation of indices suitable for the measurement of biological stability of the organic matter content in solid waste samples has been carried out. Samples from different stages in a mechanical-biological treatment (MBT) plant treating municipal solid wastes (MSW) were selected as examples of different stages of organic matter stability in waste biological treatment. Aerobic indices based on respiration techniques properly reflected the process of organic matter biodegradation. Static and dynamic respirometry showed similar values in terms of aerobic biological activity (expressed as oxygen uptake rate, OUR), whereas cumulative oxygen consumption was a reliable method to express the biological stability of organic matter in solid samples. Methods based on OUR and cumulative oxygen consumption were positively correlated. Anaerobic methods based on biogas production (BP) tests also reflected well the degree of biological stability, although significant differences were found in solid and liquid BP assays. A significant correlation was found between cumulative oxygen consumption and ultimate biogas production. The results obtained in this study can be a basis for the quantitative measurement of the efficiency in the stabilization of organic matter in waste treatment plants, including MBT plants, anaerobic digestion of MSW and composting plants.
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Compostos Orgânicos/metabolismo , Aerobiose , Anaerobiose , Oxigênio/metabolismo , Reprodutibilidade dos TestesRESUMO
In the present work, a complete study of the sewage sludge (SS) biodrying technology was conducted at bench-scale, aiming at assessing its performance and providing a valuable insight into the different gaseous emission patterns found for greenhouse gases (GHG) and odorant pollutants. As process key parameters, temperature, specific airflow, dynamic respiration index, final moisture content and Lower Calorific Value (LCV) were evaluated. At the end of the biodrying, a product with a 35.9% moisture content and a LCV of 7.1â¯MJ·kg-1product was obtained. GHGs emission factor was 28.22â¯kgCO2eq per Mg of initial mass of dry matter in the SS (DM0-SS). During the biodrying process, maximum odour concentration measured was 3043â¯ou·m-3 and the estimated odour emission factor of the biological treatment was 3.10Eâ¯+â¯07â¯ou per Mg DM0-SS. Finally, VOCs were completely identified and quantified. The most abundant VOCs found in the biodrying gaseous emissions were terpenes, sulphur-compounds and ketones.
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Gases de Efeito Estufa/química , Odorantes , Esgotos , Compostos Orgânicos Voláteis/química , TemperaturaRESUMO
Anaerobic digestion of manure is a common practice; however, the low biogas yield of manure can hamper the profitability of systems in small to medium farms. An increase in biogas yield could be achieved by co-digesting animal manure with co-substrates such as cheese whey. A Techno-economic assessment of anaerobic co-digestion of animal manure and cheese whey (cow, goat and sheep), has been carried out. The results obtained showed that for a farm with 250 adult cattle heads, the revenues generated in an anaerobic mono-digestion process are not able to offset the initial required investment. However, the co-digestion of manure with 30% of cheese whey showed a good economic performance and positive returns (Net Present values >0, Internal Rate of Return >11% and a Return of the investment in <10â¯years). Electricity selling price and biogas production are the key parameters to determine the profitability of the system.
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Queijo , Esterco , Soro do Leite/metabolismo , Anaerobiose , Animais , Biocombustíveis/economia , Bovinos , Fazendas , Feminino , Cabras , Gado , OvinosRESUMO
This study investigated, for the first time, the distribution and fate of 28 multiple-class veterinary pharmaceuticals and antibiotics (PhACs), and their corresponding antibiotic resistance genes (ARGs), in a full-scale on-farm livestock waste treatment plant. The plant relies on several technologies, including: anaerobic digestion (AD), solid-liquid separation, and two stages reverse osmosis (RO) of the liquid digestate. Tetracycline, fluoroquinolone, lincosamide and pleuromutilin antibiotics, together with anti-helmintic (flubendazole) and anti-inflammatory (flunixin) drugs were the most frequently detected compounds in livestock waste and in slaughterhouse sludge. This last fraction is used as co-substrate in the AD process and showed to be an important input source of PhACs and ARGs. In terms of treatment performance, AD exhibited moderate to low PhACs and ARGs reduction, while a large fraction (<50%) of the PhACs present in the digestate were distributed onto the solid fraction, after solid-liquid separation. Both solid and liquid digestates had relatively high copy numbers of ARGs. Finally, RO showed high rejection percentages for all PhACs (<90%), with concentrations in the low ng L-1 range in permeates, for most target PhACs. Nevertheless, moderate copy numbers of ARGs were detected in permeates.
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Agricultura , Resíduos de Drogas/análise , Resistência Microbiana a Medicamentos/genética , Gado , Drogas Veterinárias/análise , Eliminação de Resíduos Líquidos , Anaerobiose , Animais , DNA/isolamento & purificação , Osmose , Esgotos , Águas ResiduáriasRESUMO
In conventional single-stage anaerobic digestion processes, hydrolysis is regarded as the rate-limiting step in the degradation of complex organic compounds, such as sewage sludge. Two-stage systems have been proposed to enhance this process. However, so far it is not clear which are the best conditions for a two-stage anaerobic digestion process of sewage sludge, in terms of temperature and hydraulic retention time of each stage. The aim of this work was to determine the optimal conditions for the hydrolytic-acidogenic stage treating real sludge with a high concentration of total solids (40-50gL(-1)) and volatile solids (25-30gL(-1)), named high concentration sludge. The variables considered for this first stage were: hydraulic retention time (1-4 days) and temperature (55 and 65 degrees C). Maximum volatile fatty acids generation was obtained at 4 days and 3 days hydraulic retention time for 55 degrees C and 65 degrees C, respectively. Consequently, 4 days hydraulic retention time and temperature of 55 degrees C were set as the working conditions for the hydrolytic-acidogenic stage treating high concentration sludge. The results obtained when operating with high concentration sludge were compared with a low concentration sludge consisting of 17-28gL(-1) total solids and 13-21gL(-1) volatile solids. The effect of decreasing the influent sludge pH, when working at the optimal conditions established, was also evaluated.
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Esgotos/química , Anaerobiose , Concentração de Íons de Hidrogênio , Hidrólise , Oxirredução , Poluentes Químicos da Água , Purificação da ÁguaRESUMO
A complex mechanical-biological waste treatment plant designed for the processing of mixed municipal solid wastes (MSW) and source-selected organic fraction of municipal solid wastes (OFMSW) has been studied by using stability indices related to aerobic (respiration index, RI) and anaerobic conditions (biochemical methane potential, BMP). Several selected stages of the plant have been characterized: waste inputs, mechanically treated wastes, anaerobically digested materials and composted wastes, according to the treatment sequence used in the plant. Results obtained showed that the main stages responsible for waste stabilization were the two first stages: mechanical separation and anaerobic digestion with a diminution of both RI and BMP around 40% and 60%, respectively, whereas the third stage, composting of digested materials, produced lesser biological degradation (20-30%). The results related to waste stabilization were similar in both lines (MSW and OFMSW), although the indices obtained for MSW were significantly lower than those obtained for OFMSW, which demonstrated a high biodegradability of OFMSW. The methodology proposed can be used for the characterization of organic wastes and the determination of the efficiency of operation units used in mechanical-biological waste treatment plants.
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Reatores Biológicos , Eliminação de Resíduos/métodos , Aerobiose , Anaerobiose , MetanoRESUMO
In spite of being a widespread activity causing the salinization of rivers worldwide, the impact of potash mining on river ecosystems is poorly understood. Here we used a mesocosm approach to test the effects of a salt effluent coming from a potash mine on algal and aquatic invertebrate communities at different concentrations and release modes (i.e. press versus pulse releases). Algal biomass was higher in salt treatments than in control (i.e. river water), with an increase in salt-tolerant diatom species. Salt addition had an effect on invertebrate community composition that was mainly related with changes in the abundance of certain taxa. Short (i.e. 48 h long) salt pulses had no significant effect on the algal and invertebrate communities. The biotic indices showed a weak response to treatment, with only the treatment with the highest salt concentration causing a consistent (i.e. according to all indices) reduction in the ecological quality of the streams and only by the end of the study. Overall, the treatment's effects were time-dependent, being more clear by the end of the study. Our results suggest that potash mining has the potential to significantly alter biological communities of surrounding rivers and streams, and that specific biotic indices to detect salt pollution should be developed.