Environments, Volume 7, Issue 4 (April 2020) – 10 articles

It is widely known that agricultural practices can alter natural ecosystems, both from a qualitative and quantitative point of view. Indeed, over the years, the intensification of production through excessive or inappropriate use of pesticides and fertilisers in the agricultural sector has had a negative impact on natural resources. This negative environment impact has had both minor and major consequences for the natural resources present in the different areas of the European Union (EU). This variability depends mainly on the different agricultural training of farmers and on their ability to practise sustainable agriculture. Hence, with a specific set of agri-environmental indicators provided by the Eurostat database, this paper analyses the spatial and temporal variation of the agricultural land-use practices and the related environmental effects in EU countries. In pursuit of this aim, descriptive statistics and multivariate analysis (factor analysis and hierarchical cluster analysis) were adopted to determine the similarities/dissimilarities between the different types of agricultural production in the EU and the dominant dimensions of agricultural production and activities there in terms of their impact of natural resources in order to identify “homogeneity” among member states. The main contribution of this paper lies, above all, in the fact that the classification of these countries in four agro-ecosystems, with similar use of energy, pollution factors, and natural resources, could be useful as a tool for policymakers. Importantly, it could help them to define different incentives that could encourage farmers to adopt more sustainable agricultural production methods. Full article

The molecular structure of a commercial sample of humic acids (HA) was investigated by membrane dialysis experiments (MD) and low-pressure size-exclusion chromatography (LP-SEC). MD showed that HA molecules were retained by dialysis membrane with a cut-off of 6–8 kDa, independently from HA concentration (15 or 150 mg L⁻¹), NaHCO₃ concentration (0.005–2.0 mol L⁻¹), and from propan 2-ol (0–5 v/v %). SEC experiments at low pressure gave chromatograms with a broad peak, with an elution volume between those of the globular proteins bovine serum albumin (molecular weight = 66.5 kDa) and lysozyme from egg (molecular weight = 14.4 kDa). The pattern of the chromatogram did not vary with HA concentration, and second-run chromatograms of single eluted fractions showed relatively sharp peaks. From these data, we reveal that the commercial HA sample analysed has a macromolecular structure rather than being a supramolecular aggregate of relatively small molecules, as recently proposed for some samples of HA obtained from different sources. Full article

Aquatic oligochaetes, comprising a large number of species showing various degrees of resistance to chemical pollution, are recognized as valuable bioindicators of sediments’ quality. In the Geneva area (Switzerland), oligochaete tools were previously tested for assessing the biological quality of stream sediments, and effect thresholds of combined metals (quotients) in sediments were defined. The aims of the present study were to update this previous work with new data acquired in different cantons of Switzerland and to establish effect thresholds on oligochaete communities for individual metals and for combined metals. The oligochaete metrics “Oligochaete index of sediment bioindication (IOBS)”, “oligochaete density” and “percentage of tubificids without hair setae” proved pertinent for assessing the effects of metals and organic matter in sediments. We established a threshold effect level (TEL_oligo) and probable effect level (PEL_oligo) for eight metals in sediments (Cr, Ni, Zn, Cu, Pb, Cd, Hg and As) as well as a probable effect level for these metals combined (mPEL_oligo-Q). These thresholds could be used directly to screen for alteration of in situ communities restricted to sediments and/or for establishing sediment quality standards based on a combination of different biological and ecotoxicological tools. Full article

Plastic is one of the most commonly produced and used materials in the world due to its outstanding features. However, the worldwide use of plastics and poor waste management have led to negative impacts on ecosystems. Plastic degradation in the environment leads to the generation of plastic particles with a size of <5 mm, which are defined as microplastics (MPs). These represent a global concern due to their wide dispersion in water environments and unclear potential ecotoxicological effects. Different studies have been performed with the aim of evaluating the presence and impacts of MPs in the marine environment. However, the presence of MPs in freshwater systems is still poorly investigated, making data retrieval a difficult task. The purpose of this review is to identify the main aspects concerning MPs pollution sources in lakes and rivers, with a focus on freshwater sediments as a site of accumulation and as the habitat of benthic organisms, which are key components of food webs and play a fundamental role in energy/contaminant transfer processes, but are still poorly considered. Through this review, the sources and fate of MPs in freshwater are analysed, ecotoxicological studies focused on sediments and benthic fauna are exposed, the most frequently used sampling and analysis strategies are reported, and future trends of MPs analysis in this field are proposed. Full article

This paper presents integrated research on ecosystems of small lakes experiencing the direct impact of a copper-nickel ore processing plant, the “Kolskaya GMK” (MS KGMK), near the town of Monchegorsk Kola Peninsula, Russia. An integrated research method with the analysis of both abiotic and biotic components of aquatic ecosystems was used. It was found that the water ecosystems developed under the conditions of extreme pollution depleted the species composition of the hydrobionts and the number indices. Much of the pollution resulted in a transformation in the phytoplankton community structure: the share of mixotrophic algae and Cyanobacteria increased. Anthropogenic eutrophication resulted in a decrease in toxic impact. Despite high anthropogenic load, Salmonid and Coregonid species were found in a number of water bodies. The size and weight indices and the heavy metal accumulation intensity had a distinct gradient nature. The macrozoobenthos in the water bodies studied was characterized by depleted taxonomic composition and extremely low numbers. The basis of the zoobenthos was formed by chironomids Psectrocladius, Procladius, Cricotopus, and Orthocladius, spread widely in water bodies polluted with heavy metals. Full article

Five permanent sample plots (SPs; 200–250 trees per plot) were established in middle-aged high-grade suburban pine stands near the industrial city of Krasnoyarsk, Siberia, Russia. Needle damage, inventory parameters of the stands, and the defense response of the stem phloem were evaluated annually for the years 2002–2019 and attributed to acute or chronic toxic exposures (creeping fire or industrial pollutants, respectively). The results form a basis for using trees as bioindicators. A newly elaborated stem lesion test was formed from a hypothesis on the upward sugar transport for the regeneration of an injured crown, based on Eschrich’s model of bidirectional sugar transport in the phloem. The formation of a phloem lesion was induced by inoculation of the stem with a mycelial extract of the ophiostomatoid fungus Ceratocystis laricicola. The lesion length and its shift relative to the inoculation hole were measured. An increase in the length of needles at early stages of stand weakening by pollutants was found to correspond to the hormesis model (Selye’s adaptation syndrome). A possibility of assessing the chronology of pollutant toxicity and the duration of the recovery period after creeping fire was shown. Full article

In aquatic environment, engineered nanoparticles (ENPs) are present as complex mixtures with other pollutants, such as trace metals, which could result in synergism, additivity or antagonism of their combined effects. Despite the fact that the toxicity and environmental risk of the ENPs have received extensive attention in the recent years, the interactions of ENPs with other pollutants and the consequent effects on aquatic organisms represent an important challenge in (nano)ecotoxicology. The present review provides an overview of the state-of-the-art and critically discusses the existing knowledge on combined effects of mixtures of ENPs and metallic pollutants on aquatic organisms. The specific emphasis is on the adsorption of metallic pollutants on metal-containing ENPs, transformation and bioavailability of ENPs and metallic pollutants in mixtures. Antagonistic, additive and synergistic effects observed in aquatic organisms co-exposed to ENPs and metallic pollutants are discussed in the case of “particle-proof” and “particle-ingestive” organisms. This knowledge is important in developing efficient strategies for sound environmental impact assessment of mixture exposure in complex environments. Full article

Despite protection measurements and their natural position, groundwater resources are very vulnerable due to natural and anthropogenic impacts. This is especially emphasized in karst arid and semi-arid zones, due to increased requirements for water. Paper deals with the impacts of the sinkholes on groundwater quality on Abarkooh city in Iran. There are 28 sinkholes located in Abarkooh plain. The aims of the paper are to specify the characteristics and causes of sinkholes occurrence, as well as to specify the vulnerable areas and future development of sinkholes and their effect on the groundwater resources. Next step is defining of the original procedure for protection of groundwater resources in characteristic areas, as karst arid and semi-arid areas are. By taking into the account geological, hydrogeological and meteorological data, and finally through hydrogeochemical and geophysical analysis, final conclusions and recommendations for the protection of the groundwater resources are obtained. This has significant importance for water supply of the Abarkooh city in Iran. It should be noted that the mentioned methodology for the protection of groundwater resources could be applied in other arid and semi-arid areas. Full article

A variety of liquid unloading techniques are used to clear accumulated liquids from the wellbore to increase production rates for oil and gas wells. Data from national measurement studies indicate that a small subset of wells with plunger lift assist, that vent with high frequency and short event duration, contribute a significant fraction of methane emissions from liquid unloading activities in the United States. Compared to direct measurement of emissions at 24 wells in a field campaign, the most commonly used engineering emission estimate for this source category, which is based on the volume of gas in the wellbore, does not accurately predict emissions at the individual well (R² = 0.06). An alternative emission estimate is proposed that relies on the duration of the venting activity and the gas production rate of the well, which has promising statistical performance characteristics when compared to direct measurement data. This work recommends well parameters that should be collected from future field measurement campaigns that are focused on this emission source. Full article

The present study was conducted to ascertain the potential of spent coffee grounds (SCGs) as an alternative adsorbent for the removal of cadmium (Cd) from aqueous solutions. Therefore, Cd adsorption batch tests, using SCGs that had not undergone any chemical pretreatment, were conducted using Cd solutions with a wide concentration range (i.e., 0.1–120 mM) under various adsorption conditions, e.g., ion strength, pH, and solid/solution ratio. For comparison, zeolite, as a well-known common representative adsorbent, was included to determine the adsorption efficiency. The adsorption capacity of the SCGs increased with the decreasing ionic strength of the test solution from 200 to 0 mM of Ca(NO₃)₂ and the increasing solid:solution ratio from 1:4 to 1:400. The most significant factor influencing the adsorption capacity of the SCGs was the pH of the test solution, with increases in the adsorption capacity as the initial solution pH was increased from 2 to 10. However, the rate for Cd removal remained constant, at 71.19%, when the initial solution pH was between 4 and 8 due to the buffer capacity of SCGs. The obtained data were fitted with the Freundlich, Langmuir, and Dubinin-Radushkevich isotherm models. The Langmuir isotherm provided the best correlation for Cd adsorption onto SCGs (R² = 0.96) and zeolite (R² = 0.92), and the maximum Cd adsorption capacity of the SCGs was 19.32 mg g^-1, which was higher than that of zeolite (13.91 mg g⁻¹). These results mean that the SCGs can be utilized as alternative low-cost biosorbents to replace conventional adsorption materials. Full article