Search Results (6)

The ongoing anthropogenic pollution of the biosphere with As, Cd, Hg and Pb will inevitably result in an increased influx of their corresponding toxic metal(loid) species into the bloodstream of human populations, including children and pregnant women. To delineate whether the measurable concentrations of these inorganic pollutants in the bloodstream are tolerable or implicated in the onset of environmental diseases urgently requires new insight into their dynamic bioinorganic chemistry in the bloodstream–organ system. Owing to the human exposure to multiple toxic metal(loid) species, the mechanism of chronic toxicity of each of these needs to be integrated into a framework to better define the underlying exposure–disease relationship. Accordingly, this review highlights some recent advances into the bioinorganic chemistry of the Cd²⁺, Hg²⁺ and CH₃Hg⁺ in blood plasma, red blood cells and target organs and provides a first glimpse of their emerging mechanisms of chronic toxicity. Although many important knowledge gaps remain, it is essential to design experiments with the intent of refining these mechanisms to eventually establish a framework that may allow us to causally link the cumulative exposure of human populations to multiple toxic metal(loid) species with environmental diseases of unknown etiology that do not appear to have a genetic origin. Thus, researchers from a variety of scientific disciplines need to contribute to this interdisciplinary effort to rationally address this public health threat which may require the implementation of stronger regulatory requirements to improve planetary and human health, which are fundamentally intertwined. Full article

This article introduces a new web-based and freely accessible tool, the Nitrate Fate tool (NFt), for the assessment of groundwater vulnerability to nitrate pollution in a variety of pedoclimatic conditions. The contamination of water resources by nitrate, in fact, represents a growing and persistent global environmental problem, and the utilization of practical tools to assist personnel working in the agricultural sector is key for mitigating the impact on land use, while maintaining farmers’ incomes. The (NFt) has been developed and integrated into the geospatial decision support system, LandSupport, as a way to support multiple stakeholders in conducting the so-called what-if scenario analysis (e.g., what would happen to the crop production if I substitute a quote of inorganic fertilizer with the same quote of an organic one?). The tool couples a state-of-art crop-growth model—which simulates crop growth dynamics, the nitrogen and carbon cycles—with a novel transfer function model in order to assess the transport of nitrate through the unsaturated zone to the groundwater table. Within the LandSupport platform, the results are shown both as coloured maps and as cumulative charts representing the travel times and the concentrations of root leachate to groundwater table depths. This work details the tool’s rationale, the coupling of the models, and their implementation. Moreover, this article shows examples of applications supporting several public authorities and end-users, underlining that, by combining all of the information on soils, groundwater table depths, management and climates, it is possible to obtain a comprehensive understanding of nitrogen transport dynamics. Two case studies are presented: the Piana del Sele and the eastern plain of Naples, both located in the Campania region of Italy. The results of the tool’s applications reveal significant groundwater vulnerability in both plains, mainly due to the shallow groundwater table depths, resulting in remarkably fast mean nitrate travel times ranging from 0 to 6 years. Finally, the tool provides a reproducible and replicable solution, and future implementation is foreseen for additional case studies all over the world. Full article

Indiscriminate and injudicious application of inorganic fertilizers and irrigation, respectively, cause declines in crop productivity as well as environmental pollution. Therefore, judicious use of organic manures and proper scheduling of irrigation are required for sustainable production of wheat crops. A two-year (2014–2015 and 2015–2016) study was conducted to determine the wheat nutrient uptake, soil moisture, and grain yield as a result of organic manures and irrigation schedule. The experiment was set up with four treatments of organic manure in four subplots with repellents and five irrigation planning treatments in the main plot. The results showed that an irrigation/water ratio of 0.9 irrigation water depth/cumulative pan evaporation (I₂) increased grain yield, soil moisture content, and nutrient uptake of wheat (I₃) compared to 0.6 IW/CPE during the vegetative period and 0.8 IW/CPE during the reproductive period. According to statistics, it was found that the vegetative period is maintained at 0.8 IW/CPE, and the reproductive period is maintained at 1.0 IW/CPE (I₅). Applying 7.5 Mg ha⁻¹ of farmyard manure (FYM) plus 3 Mg ha⁻¹ of vermicompost while employing organic manure increases grain output, soil moisture content, and nutrient content and absorption compared to the control treatment. Therefore, it is concluded that irrigation either at I₂ or I₅ + FYM at 7.5 Mg ha⁻¹ + vermicompost at 3 Mg ha⁻¹ could be recommended for enhancing grain of wheat cultivation, particularly in the semiarid regions of northwestern India. Full article

The problem of shortage in freshwater resources in many countries around the world has led to the use of unconventional water resources such as treated wastewater and agricultural drains water to bridge the gap between the demand and supply. However, the open nature of most agricultural drains and the spread of population cumulation around them has made them vulnerable to many organic and inorganic pollutants. One of the artificial methods used to enhance the self-purification process in polluted streams is submerged biofilters (SB). However, most of the previous studies focused on the efficiency of the biofilter to remove the pollutants, and there is a lack of studies on hydraulic changes. This study aims to assess the hydraulic effects of the submerged biofilter of star-shaped plastic media on water streams and develop a mathematical formula that could predict such effects. For this purpose, an experimental study was conducted with 60 total runs (30 for flow through biofilter and 30 for flow over biofilter), and dimensional analyses with multi-linear regression analysis were used to correlate different parameters that affect the flow through and over the biofilter. The mathematical relationships were developed to determine the changes in the upstream water level and that heading up in streams due to the use of the biofilter for both cases of flow. The results of the new formulas are very close to the experimental results, with (R² = 0.89) for flow through the biofilter and (R² = 0.993) for the flow over biofilter. In addition, the results were very close to other developed equations. The developed formulas were used to predict the upstream water depth (h₁) by knowing the discharge (Q), length (L), and width (B) of the biofilter. Full article

Perchlorate is a well-known thyroid-disrupting chemical as well as an extremely stable inorganic pollutant widely distributed in the environment. Therefore, perchlorate posts potential risks to the environment as well as human health. Crayfish is a dominant aquatic food with increasing consumption levels in recent years. It is crucial to evaluate the accumulation of perchlorate with well-water-soluble properties in crayfish and to assess its health risks. In our present study, we obtained crayfish samples from cultivated ponds and markets based on the regions of the Middle and Lower Reaches of the Yangtze River. The perchlorate concentration was measured in all 206 samples using ultra-high performance liquid chromatography coupled with mass spectrometry (UPLC–MS). Monte Carlo simulation was used to perform health risk assessments. The results indicated that perchlorate levels ranged from 7.74–43.71 μg/kg for cultivated crayfish and 4.90–16.73 μg/kg for crayfish sold in markets. The perchlorate accumulation mainly occurred in exoskeleton parts. All the HQ values were remarkable, at less than one—indicating that perchlorate exposure through the ingestion of crayfish does not pose an appreciable risk to human health. Full article

High living standards and a comfortable modern way of life are related to an increased usage of various plastic products, yielding eventually the generation of an increased amount of plastic debris in the environment. A special concern is on microplastics (MPs), recently classified as contaminants of emerging concern (CECs). This review focuses on MPs’ adverse effects on the environment based on their bioactivity. Hence, the main topic covered is MPs’ ecotoxicity on various aquatic (micro)organisms such as bacteria, algae, daphnids, and fish. The cumulative toxic effects caused by MPs and adsorbed organic/inorganic pollutants are presented and critically discussed. Since MPs’ bioactivity, including ecotoxicity, is strongly influenced by their properties (e.g., types, size, shapes), the most common classification of MPs types present in freshwater are provided, along with their main characteristics. The review includes also the sources of MPs discharge in the environment and the currently available characterization methods for monitoring MPs, including identification and quantification, to obtain a broader insight into the complex problem caused by the presence of MPs in the environment. Full article