Artisanal and small-scale gold mining (ASGM) accounts for almost half of anthropogenic mercury (Hg) emissions worldwide and causes widespread water pollution. In Indonesia, several studies have identified harmful levels of Hg in areas affected by ASGM. While most of these studies focus on mining areas with thousands of miners, water contamination in smaller ASGM areas is less understood. We evaluated Hg contamination in four ASGM areas in Central Java of varying scale (from 30 to 3000 amalgamator barrels at each area), including Jatiroto, Kebonsari, Gumelar, and Kulon Progo. At each location, we collected water samples along river transects upstream and downstream of ASGM areas during the dry season (June–July 2017). Total Hg (THg) concentrations in stream water increased by orders of magnitude from upstream to downstream of ASGM activities at Jatiroto (1.35–4730 ng/L), with smaller observed increases at the other locations. Dissolved THg concentrations exceeded USEPA criteria for aquatic life (12 ng/L) at two of the four ASGM areas. THg concentrations in tailings exceeded 150,000 ng/L. Notably, THg concentrations in stream water were not directly related to the scale of mining, with Jatiroto having the highest concentrations as second smallest mining areas of the four in this study. Downstream of the mining areas, the fraction of dissolved methyl Hg to dissolved THg reached 20%, indicating that active Hg methylation occurs in the watersheds. Further study is needed to investigate Hg transport in the wet season when rainfall and high stream discharge may mobilize contaminated sediment near mining areas.

The biosphere is polluted with metals due to burning of fossil fuels, pesticides, fertilizers, and mining. The metals interfere with soil conservations such as contaminating aqueous waste streams and groundwater, and the evidence of this has been recorded since 1900. Heavy metals also impact human health; therefore, the emancipation of the environment from these environmental pollutants is critical. Traditionally, techniques to remove these metals include soil washing, removal, and excavation. Metal-accumulating plants could be utilized to remove these metal pollutants which would be an alternative option that would simultaneously benefit commercially and at the same time clean the environment from these pollutants. Commercial application of pollutant metals includes biofortification, phytomining, phytoremediation, and intercropping. This review discusses about the metal-accumulating plants, mechanism of metal accumulation, enhancement of metal accumulation, potential commercial applications, research trends, and research progress to enhance the metal accumulation, benefits, and limitations of metal accumulators. The review identified that the metal accumulator plants only survive in low or medium polluted environments with heavy metals. Also, more research is required about metal accumulators in terms of genetics, breeding potential, agronomics, and the disease spectrum. Moreover, metal accumulators’ ability to uptake metals need to be optimized by enhancing metal transportation, transformation, tolerance to toxicity, and volatilization in the plant. This review would benefit the industries and environment management authorities as it provides up-to-date research information about the metal accumulators, limitation of the technology, and what could be done to improve the metal enhancement in the future.

The main purpose of our research was to assess the chronic exposure of red foxes to Cd, Pb and Zn. We have determined concentrations of these metals in the kidney, liver and muscle of 36 red foxes hunted between December 2002 and March 2003 in differently polluted areas in southern Poland. Tissue concentrations of Pb and Cd in the red foxes significantly co-varied with concentrations of these elements in the soil, and differed between the tissues. We compared concentrations of Pb, Cd, and Zn in red foxes with two rodent species, Apodemus flavicollis and Myodes glareolus, trapped simultaneously in the same area. Concentrations of Pb and Cd appeared significantly higher in the red foxes than in the rodents, but the slopes of the relationship between metal concentrations in tissues and in soil were similar in all species. This indicates that extrapolation from results of monitoring studies conducted on rodents to mammalian carnivores is possible but requires applying an extrapolation factor.

The effects of solid content (10–80 g/L) on the bioleaching of heavy metals (HMs) from pig manure (PM) were investigated using indigenous sulfur-oxidizing bacteria. The results showed that an increase in solid content increased the PM buffering capacity, which slowed the rates of pH reduction, ORP increase, and sulfur oxidation and decreased the solubilization efficiency of HMs from PM. Approximately 75–99% of Cu, 76–99% of Zn, and 55–88% of Mn were leached from PM with solid contents of 10–80 g/L after 28 days of bioleaching. However, the content of HMs in bioleached manure did not meet the requirement for agricultural application when the solid content was ≥ 60 g/L after 28 days of bioleaching. The solubilization of HMs from PM was well-described by a kinetic equation. Regression analysis showed that Cu solubilization was primarily controlled by ORP, and pH seemed to be the sole factor responsible for the solubilization of Zn and Mn. Additionally, nutrient (N, P, K, and organic matter) loss significantly increased when PM solid content decreased from 40 to 20 g/L. Therefore, the recommended solid content for the bioleaching of HMs from PM is 40 g/L.

Recent efforts to aggregate, process, and use biodiversity information have appended novel opportunities and challenges for the field, and a rapid increase in studies that integrate and analyze data in the biological-ecological realm. We developed a web-based GIS system for the wildlife of Khouzestan Province that provides potential distribution maps and other spatial and nonspatial data on the wildlife of Khouzestan Province and its protected areas. We used MaxEnt and a fuzzy inference system to model distributions of species. Our application was structured using a client/server architecture, and the database design and construction was carried out using PostgreSQL/PostGIS, and GeoServer to serve maps. The mapping interface was developed using OpenLayers; ASP.NET was selected for designing the user interface. We used qualitative-quantitative methods to develop, design, refine, and finalize our system particularly as regards usability. The design approach resulted in a user-friendly interface that allows both specialists and non-specialists to quickly and efficiently run models to estimate potential distributions of species. Our application highlights what can be accomplished with a biodiversity-oriented web application.

Metropolitan areas may suffer with increase of air pollution due to the growth of urbanization, transportation, and industrial sectors. The Metropolitan Area of Vitória (MAV) in Brazil is facing air pollution problems, especially because of the urbanization of past years and of having many industries inside the metropolitan area. Developing air quality system is crucial to understand the air pollution mechanism over these areas. However, having a good input dataset for applying on photochemical models is hard and requires quite of research. One input file for air quality modeling which can play a key role on results is the lateral boundary conditions (LBC). This study aimed to investigate the influence of LBC over CMAQ simulation for particulate matter and ozone over MAV by applying four different methods as LBC during August 2010. The first scenario (M1) is based on a fixed, time-independent boundary conditions with zero concentrations for all pollutants; the second scenario (M2) used a fixed, time-independent concentration values, with average values from local monitoring stations; the third CMAQ nesting scenario (M3) used the nested boundary conditions varying with time from a previous simulation with CMAQ over a larger modeling domain, centered on MAV; and finally, the fourth GEOS-Chem scenario (M4) used the boundary conditions varying with time from simulations of global model GEOS-Chem. All scenarios runs are based on the same meteorology conditions and pollutant emissions. The air quality simulations were made over a domain 61 × 79 km centered on coordinates − 20.25° S, − 40.28° W with a resolution of 1 km. The results were evaluated with the measured data from the local monitoring stations. Overall, significant differences on concentrations and number of chemical species between the LBC scenarios are shown across all LBC scenarios. The M3 and M4 dynamic LBC scenarios showed the best performances over ozone estimates while M1 and M2 had poor performance. Although no LBC scenarios do not seem to have a great influence on total PM₁₀ and PM₂.₅ concentrations, individual PM₂.₅ species like Na, NO₃⁻, and NH₄⁺concentrations are influenced by the dynamic LBC approach, since those hourly individual PM₂.₅ species from CMAQ nesting approach (M3) and GEOS-Chem model (M4) were used as an input to LBC.

Selenium (Se) is a vital element which leads to strong antioxidation in animals and humans. However, the mechanism underlying natural cereal Se–induced biological changes is not well understood. This study intended to explore the gene differential expression in naturally aged mice exposed to selenium by RNA-Seq technique. A total spectrum of 53 differentially expressed genes was quantified in mice heart tissues treated with Se-rich and general rice. The GO functional annotation of differentially expressed genes disclosed the enrichment of cellular process, ionic binding, biological regulation, and catalytic activity. One hundred twenty-three differential pathways (cardiovascular diseases, immune system, transport and catabolism, longevity regulating, and PI3K-AKT signaling) were identified according to KEGG metabolic terms. Afterwards, the effect of Se-rich rice on the antioxidant activity was assessed. The selenium-rich diet increased the total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) in mice serum and livers while significantly reduces methane dicarboxylic aldehyde (MDA) contents. FOXO1 and FOXO3 genes, which acted as the regulators of apoptosis and the antioxidant enzyme, were significantly enhanced in mice when fed with Se-rich rice. In short, the present findings disclosed the alluring insights of organic and inorganic selenium sources on certain biological processes and antioxidant activity of living bodies. However, long-term trials are still required to draw a definitive conclusion, including risks and benefit analysis for various management strategies.

The most commonly used solution in chrome plating bath is chromic acid (hexavalent Cr), and a considerable amount of mists is released into the air and consequently produce hazards to workers. Thus, the aim of this study was to evaluate whether the biomarker of exposure to metals, specially Cr levels, presents associations with hematological and biochemical parameters and if they can alter the activity of enzymes that contain thiol groups such as pyruvate kinase, creatine kinase, adenylate kinase, and δ-aminolevulinate dehydratase. Fifty male chrome plating workers were used for exposed group and 50 male non-exposed workers for control group. For that, biological monitoring was performed through quantification of metals on total blood and urine by inductively coupled plasma mass spectrometry (ICP-MS) and enzyme activity was performed by spectrometry in erythrocytes. In addition, chromium levels in water was quantified and ecotoxicology assay was performed with Allium cepa test. The results demonstrated that blood and urinary chromium levels in exposed group were higher than the control group (p < 0.0001). Furthermore, decreased activity of enzymes was found in those that contain thiol groups from exposed group when compared with the control group (p < 0.001). The water analysis did not present a statistical difference between control and exposed groups (p > 0.05), demonstrating that water did not seem to be the source of contamination. In summary, our findings indicated some toxicology effects observed in the exposed group, such as thiol enzyme inhibition, mainly associated with occupational exposure in chrome plating and besides the presence of other metals, and Cr demonstrated to influence the activity of the enzymes analyzed in this research.

Environmentally mediated sensitivity of Lemna minor to copper (Cu) was evaluated for the first time in three experiments: the effects of two levels of nutrient concentration, light irradiance or Cu pre-exposure were tested. Various Cu concentrations (ranging from 0.05 to 0.25 mg/L) were used to assess the sensitivity of L. minor to this metal, using one common strain previously acclimatized to two different levels of light intensity, nutrient enrichment and Cu pre-exposure. Our results showed a phenotypic plastic response of the relative growth rates based on frond number and fresh mass production, and maximum quantum yield of photosystem II (Fᵥ/Fₘ). Growth was affected by the three environmental conditions both prior and during Cu exposure, whereas Fᵥ/Fₘ was mostly affected during Cu exposure. Copper significantly influenced all the parameters measured in the three experiments. Environmental conditions significantly modified L. minor sensitivity to Cu in all experiments, with up to twofold difference depending on the treatment. Growth rate was the parameter that was most impacted. Our study revealed for the first time the existence of phenotypic plasticity in L. minor sensitivity to chemical contamination, and implies that environmental context needs to be taken into account for a relevant risk assessment.

Considerable researches on removal of azo dyes have been reported in recent years, but few researchers have documented adsorption and/or transformation of anthraquinone dyes by physical, chemical, or biological treatment methods due to their fused aromatic structures. In this study, tea residue was found to have significant enhancement effect on the decolorization of anthraquinone dye reactive blue 19. This effect worked on different dye decolorizing bacterial florae and the natural bacterial flora from surface water and exhibited universal feature. Six single bacterial strains were isolated from bacterial flora DDMY2. Unexpectedly, all of them had poor decolorization capacity. High-throughput sequencing results revealed the community evolution of bacterial flora DDMY2 cultured with tea residue after 6 months and 12 months. It was found that the community structure changed dramatically because the influence of tea residue and the dominant functional genera, such as unclassified_o_Pseudomonadales, Stenotrophomonas, Bordetella, and Brevibacillus, was significantly enriched. Meanwhile, the evolved community structure could keep stable for a long time, resulting in the decolorization effect stabilized for a long time. This study provides the tea residue as the bioactivator that can be applied to boost the decolorization of dyes by various potential bacterial florae. It also enlarges our knowledge of making full use of biowaste in biological wastewater treatment.