Responses of morphological, physiological, and biochemical characteristics of maize ( Zea mays L.) seedlings to atrazine stress Abstract Atrazine is a synthetic herbicide applied to control broadleaf weeds in different crops. In many parts of the world, atrazine is mainly applied for controlling weeds in maize fields. However, studies on the possible adverse effects of atrazine on maize crop can hardly be found in literature. The present study was therefore conducted to evaluate the effect of atrazine on different characteristics of maize seedlings including germination, growth, chlorophyll contents, soluble sugars, proteins and proline levels, ions accumulation, cell viability, and cell injury. In addition, the effects of atrazine on reactive oxygen species (ROS) accumulation and antioxidant enzymes activities in maize seedlings were estimated. It was found that at high concentration, atrazine slightly but significantly inhibited seed germination and growth of maize seedlings. Light-harvesting pigments (chlorophylls a and b, and total carotenoids) exhibited a higher sensitivity to atrazine and were negatively impacted by atrazine at doses above 50 ppm. Atrazine caused an increase in soluble sugars at all tested doses and decrease in soluble proteins at the highest tested dose. Exposure of maize seedlings to atrazine resulted in an increased cell injury and decreased cell viability. Atrazine did not affect the concentration of Na+, K+, and Ca2+ ions in maize seedlings to any greater extent; however, some minor changes were observed in some cases. An increase in the stress marker, proline, was found upon exposure to atrazine. The observed effects of atrazine in maize seedlings can be attributed to oxidative stress as revealed by an increase in H2O2 content and higher activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) enzymes in atrazine-treated seedlings. The present investigation concludes that atrazine has the potential to adversely affect germination and growth of maize seedlings by inducing oxidative stress that causes increased cell injury and decreased cell viability as well as impairs the concentration of light-harvesting pigments.

Respiratory and non-respiratory symptoms associated with pesticide management practices among farmers in Ghana’s most important vegetable hub Abstract The data presented here are from the Offinso North District Farm Health Study (ONFAHS), a population-based cross-sectional study among vegetable farmers in Ghana. The paper addresses knowledge, pesticide handling practices, and protective measures related to pesticide use by self-reported symptoms for 310 adult farmers who completed a comprehensive questionnaire on pesticide management practices and health. In addition, an inventory was prepared using information supplied by pesticide sellers/dealers in this district. We report that cough and wheezing (but not breathlessness) are positively associated with stirring pesticide preparations with bare hands/drinking water while mixing/applying pesticides, and stirring pesticide preparations with bare hands/drinking water/smoking cigarettes while mixing/applying pesticides. There is a significant exposure-response association between the number of precautionary measures practiced while handling pesticides and cough and wheezing but not with breathlessness. We also found unsafe practices to be associated with sexual dysfunction, nervousness, and lack of concentration. The results also suggest a negative association between practice of any precautionary measure when mixing/applying pesticides and sexual dysfunction, nervousness, and lack of concentration. We found that in spite of the fact that farmers have adequate knowledge about the environment and health effects of pesticides, several unhygienic practices are in widespread use, indicating that knowledge is not necessarily always translated in action. Further action is necessary to promote the safe use of pesticides and to replace existing poor management practices among these and other farmers in Ghana.

Correction to: Assessing climate boundary shifting under climate change scenarios across Nepal The original version of this article unfortunately contained an error. All “50s” and “70s” were replaced by “1950s” and “1970s” throughout the published paper.

Stripping traditionally productive Calcisols for tandir oven manufacturing in Diyarbakır, a semi-arid region in SE Turkey Abstract There is a close connection between human history and different purposes for which land is used, and various purposes can lead to the loss of productive agricultural lands. The increasing population in recent decades has particularly increased the pressure on agricultural lands. Despite the large number of land/soil misuse studies conducted during this period, land/soil loss is a continuing process. We thus seek to highlight the land/soil loss caused by the use of soil materials for the construction of tandır ovens in Diyarbakır region. The use of traditional tandır ovens is particularly widespread in eastern and northeastern rural Anatolia of Turkey, for baking bread. Because the soil material used in the production of this oven does not have any production standards, tandır oven producers extract their material from the nearest available lands that are mostly productive. Consequently, this study was conducted by collecting samples from soil materials used in the production of tandır ovens to determine their agricultural productivity. Satellite imagery from different dates was also used to detect the effects of inappropriate soil extraction. A number of interviews were conducted to obtain information on the type of soils extracted for production. Laboratory analyses of samples collected from the extracted areas revealed that soils’ utilized for oven production physical and chemical properties, as well as their land characteristics (flatness, depth, and stoniness), were appropriate for crop production. Consequently, these results point to accelerated future soil degradation which will threat regions food production.

Evaluating deciduous tree leaves as biomonitors for ambient particulate matter pollution in Pittsburgh, PA, USA Abstract Fine particulate matter (PM2.5) air pollution varies spatially and temporally in concentration and composition and has been shown to cause or exacerbate adverse effects on human and ecological health. Biomonitoring using airborne tree leaf deposition as a proxy for particulate matter (PM) pollution has been explored using a variety of study designs, tree species, sampling strategies, and analytical methods. In the USA, relatively few have applied these methods using co-located fine particulate measurements for comparison and relying on one tree species with extensive spatial coverage, to capture spatial variation in ambient air pollution across an urban area. Here, we evaluate the utility of this approach, using a spatial saturation design and pairing tree leaf samples with filter-based PM2.5 across Pittsburgh, Pennsylvania, with the goal of distinguishing mobile and stationary sources using PM2.5 composition. Co-located filter and leaf-based measurements revealed some significant associations with traffic and roadway proximity indicators. We compared filter and leaf samples with differing protection from the elements (e.g., meteorology) and PM collection time, which may account for some variance in PM source and/or particle size capture between samples. To our knowledge, this study is among the first to use deciduous tree leaves from a single tree species as biomonitors for urban PM2.5 pollution in the northeastern USA.

Association of metals with geochemical phases in wetland soils of a Ramsar site in India Abstract Mobilization of metals in wetland ecosystems is a function of the behaviour of a specific metal species and is dependent largely on the prevailing micro-environmental conditions. Apparently, five different chemical forms of metals are known with varying affinity to binding sites, mobility, bioavailability and toxicity. Quantification of these forms of metals in the soils is imperative in predicting their biogeochemical fate and toxicity. In this context, we examined the association of Cu, Pb and Zn, with various geochemical phases in the soil profile of wetland system of Keoladeo National Park, a Ramsar site in India. The assessment covered the soil profile until 100 cm depth at every 25-cm intervals. Different operationally defined geochemical phases in the soil at different depths were examined during the study for respective metal concentrations. Hydrous oxides of Fe-Mn were the major carrier for all the three metals and the fraction associated with exchangeable phase was the least. The low organic matter content in the soil seems to be influencing the metal association with the organic matter (OM-S) phase, which was also a less preferred carrier for metals. For Cu (5.8–78.4%) and Pb (33.5–88.5%), Fe-Mn hydroxide phase was an important binding site and for Zn (31.02–79.03%), it was the silicate mineral matrix (RES phase). This suggests the importance of micro-environmental conditions in the wetland bed such as redox and pH in mobilization of metals. As metals such as Pb have high eco-toxicological potential, an assessment of fractional concentrations of metals provides insights into their mobility and bioavailability in aquatic ecosystems. This aids wetland managers to develop appropriate strategy to maintain quality of inflow water, the single most crucial factor for a wetland ecosystem, and thus controls the micro-environmental conditions.

The nature and way of root adaptation of juvenile woody plants Sorbus and Pyrus to drought Abstract The functional root traits of Pyrus pyraster (L.) Burgsd. and Sorbus domestica L. during early growth stages were evaluated. The aim of the study was to identify the functional traits of root systems that determine the adaptability of these woody species to drought conditions. The experiment was carried out under the controlled environment of a growth chamber. The root systems were analyzed using WinRhizo software. Several functional root traits were identified, including specific root length, root surface area, root length, root volume, root-to-shoot mass ratio (R:S), fine root (ϕ ˂ 2 mm) volume, coarse root (ϕ > 2 mm) volume, and fine-to-coarse root volume ratio (F/C). In drought, P. pyraster maintained the absorptive root surface unchanged, when increased the volume of the fine root fraction. The different strategy of adaptation to drought has been confirmed for S. domestica, which accumulated more dry mass in the root system in comparison to aboveground organs (significant increase of R:S ratio). The functional root traits analyzed here were species-dependent. The key functional traits that indicate the responses of studied tree taxa to drought conditions include root thickening, F/C, and R:S. Increased values of these parameters indicate the investment of the plant towards root extension. A higher proportion of fine roots increases the absorbing surface of the root system, thereby promoting water uptake from the soil.

Treatment of aqueous wastes by means of Thermophilic Aerobic Membrane Reactor (TAMR) and nanofiltration (NF): process auditing of a full-scale plant Abstract This work focuses on the Thermophilic Aerobic Membrane Reactor (TAMR) process. The research was carried out on a full-scale facility where, all along a 12-year period, daily monitoring and process audit tests were conducted for the process analysis and optimization. The plant treated -light and high-strength aqueous wastes and two different configurations were adopted: (1) thermophilic biological reactor + ultrafiltration (TAMR) and (2) TAMR + nanofiltration (TAMR + NF). In the latter case, the average chemical oxygen demand removal yield was equal to 89% and an effective denitrification (nitrogen oxides removal equal to 96%) was achieved by reducing the dissolved oxygen concentration in the bioreactor. Low specific sludge production was observed. Poor sludge settling properties were measured by a lab-scale settling test; respirometric tests (nitrogen uptake rate and ammonia uptake rate) showed the presence of denitrification and the inhibition of nitrification. Hydrodynamic tests revealed the presence of a significant dead space, thus showing room for improving the overall process performance. Finally, the rheological properties of the sludge were measured as a function of the biomass concentration, pH, temperature, and aeration scheme.

Land use regression for spatial distribution of urban particulate matter (PM 10 ) and sulfur dioxide (SO 2 ) in a heavily polluted city in Northeast China Abstract Particulate material 10 μm (PM10) and sulfur dioxide (SO2) are representative air pollutants in Northeast China and may contribute more to the morbidity of respiratory and cardiovascular disease than may other pollutants. Up to now, there have been few studies on the relation between health effect and air pollution by PM10 and SO2 in Northeast China, which may be due to the lack of a model for determination of air pollution exposure. For the first time, we used daily concentration data and influencing factors (different type of land use, road length and population density, and weather conditions as well) to develop land use regression models for spatial distribution of PM10 and SO2 in a central city in Northeast China in both heating and non-heating months. The final models of SO2 and PM10 estimation showed good performance (heating months: R2 = 0.88 for SO2, R2 = 0.88 for PM10; non-heating months: R2 = 0.79 for SO2; R2 = 0.87 for PM10). Estimated concentrations of air pollutants were more affected by population density in heating seasons and land use area in non-heating seasons. We used the land use regression (LUR) models developed to predict pollutant levels in nine districts in Shenyang and conducted a correlation analysis between air pollutant levels and hospital admission rates for childhood asthma. There were high associations between asthma hospital admission rates and air pollution levels of SO2 and PM10, which indicated the usability of the LUR models and the need for more concern about the health effects of SO2 and PM10 in Northeast China. This study may contribute to epidemiological research on the relation between air pollutant exposure and typical chronic disease in Northeast China as well as providing the government with more scientific recommendations for air pollution prevention.

Mobility, distribution, and potential risk assessment of selected trace elements in soils of the Nile Delta, Egypt Abstract Environmental pollution has received considerable attention over the last 50 years. Recently, there has been an increasing interest in pollution of the Nile Delta, Egypt, which is one of the longest settled deltaic systems in the world. Pollution in the delta is increasingly recognized as a serious health concern that requires proper management of ecosystems. Therefore, this project aimed to study the distribution and assess the risk associated with selected trace elements (TEs) in different soils (i.e., marine, fluvial, and lacustrine parent materials) in the northern Nile Delta. Mehlich-3 extraction was used to determine the availability of antimony, vanadium, strontium, and molybdenum in agro-ecosystems in this area and their spatial distributions were investigated. Five indices were used to assess ecological risk. Results showed that TEs were higher in the southern part of the study area because it is affected by multiple pollution sources. The available concentrations of TEs were Sr < V < Sb < Mo. The bioavailability of Sr was highest among the studied TEs. The studied indices suggested the study area was moderately polluted by Sr and Sb. Furthermore, the results showed that marine soils had higher TE levels then lacustrine and fluvial soils. The ecological risk assessment indicated that V and Mo were of natural origin, while Sr and Sb were anthropogenically linked. Therefore, the situation calls for planning to reduce pollution sources, especially in the protected north Nile Delta, so these productive soils do not threaten human and ecological health.