Mutual sorption interactions between heavy metals, humic acids and fungi were evaluated in this article. While the relative amount of sorbed As(V), Sb(III) and Pb(II) slightly decreased or remained unchanged, the sorption capacity of Zn(II) increased significantly with increasing amounts of immobilized humic acids in the Ca-alginate beads. Therefore, zinc is most likely preferentially sorbed to functional groups provided by humic acids rather than carboxyl or hydroxyl groups of alginate, with an optimum pH for uptake between 4 and 6. Nevertheless, the removal efficiency of metal(loid)s by unmodified Ca-alginate beads or those with humic acids modification was highest for Pb(II), at up to 93.5 %. The pH value also affects humic acids sorption properties on microbial surfaces. While the highest humic acids sorption capacity of mycelial pellets prepared from Aspergillus niger occurred at pH 8.5 (231 mg g⁻¹), the pelletized Aspergillus clavatus biomass was more effective in acidic solution and 199 mg g⁻¹was recorded there at pH 5.5. The effect of mutual interactions between humic acids and mycelial pellets on Zn(II) immobilization indicates that zinc affinity is higher for the fungal surface than for humic acids which do not supply sufficient active sorption sites for zinc. This resulted in less sorption capacity of the mycelial pellets modified with humic acids compared to the unmodified biomass.

Background. Industrial waste produced from raw-material processing and manufacturing is mostly metallic in nature. In the Philippines, cadmium (Cd) monitoring in drinking water is used as a parameter for water quality testing. Cadmium in drinking water comes mainly from the dissolution of Cd ions from plumbing materials and by-products of mining, electroplating, and other industrial operations. Objective. The biosorption potential of heat-killed yeast biomass from ripe fruit peels was studied for cadmium in oxidative state 2 at concentrations of 12, 20, and 35 mg/L. Methods. Maximum biosorption of Cd (II) for the 3 Candida species was attained at pH 6 using 10 mg of the sorbent dosage of each species for 1 hour at 30 mg/kg Cd (II). Biosorption of Cd (II) and other heavy metals such as chromium, lead and copper was measured in microcosm using filter-sterilized water samples from the Marilao River in Bulacan Province. Results. Of the 41 yeast isolates evaluated for their tolerance to various Cd (II) concentrations, 3 species of Candida [C. guilliermondii B1, C. lusitaniae B3, and 6 strains of C. famata (B9, B13, B15, B16, P29, and P33)] tolerated 230 mg/L Cd (II). Biosorption ability was dependent on pH, sorbent dosage, contact time, and increasing metal concentration. Results showed that the 3 Candida spp. absorbed mostly chromium, as it was the metal present in the highest concentration in the solution. Conclusions. The ability of dead yeast cells to absorb metals indicates the possibility that these organisms can be used for treating wastewater, especially in developing countries like the Philippines. Competing Interests. The authors declare no competing financial interests.

Background. The accumulation of toxic metals in marine environments has become a problem of increasing concern. In Tanzania, large amounts of industrial and domestic waste from major coastal cities such as Dar es Salaam, Tanga and Zanzibar are released into the marine environment without undergoing treatment. The wastes are sometimes contaminated with hazardous heavy metals such as lead, zinc and cadmium, among others. Elevated concentrations of these metals have been measured in sediment along the coastal waters of Tanzania. These metals have effects on both aquatic organisms and humans through consumption of contaminated fish and other aquatic foods. Despite the social-economic support provided by marine biota, there is no information on the levels and magnitude of octopus contamination by heavy metals or their safety for human consumption. Objective. Investigate the spatial concentrations of lead in the muscle tissue and liver of O. cyanea and sediment in the coastal waters off Dar es Salaam and Tanga, Tanzania. Methods. Concentrations of lead, from samples of O. cyanea muscle and liver tissue and sediment, were determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES). Results. The concentration of lead in the muscles and liver of O. cyanea ranged from 0.01 to 21.6±2.41 μg/g. On the other hand, the concentration of lead in sediment ranged from 6.33±0.39 to 13.85±3.31 μg/g. Discussion. Levels of lead were detected in the muscle and liver tissues of the O. cyanea, but presumably, below toxic risk if provisional tolerable weekly intake (PTWI) levels are considered. However, the present results should be taken as worrisome in view of health implications for populations that depend on octopus as a source of protein. Sediment samples were below both Florida’s ‘No effect level’ and the threshold value of Environment Canada. Competing Interests. The authors declare no competing financial interests.

Petroleum hydrocarbons are among the most important contaminants in aquatic ecosystems, but the effects of different petroleum components on the archaeal communities in these environments are still poorly investigated. Therefore, the effects of representative alkanes, polycyclic aromatic hydrocarbons and crude oil on archaeal communities from marine (Massambaba Beach) and hypersaline waters (Vermelha Lagoon) from the Massambaba Environmental Protection Area, Rio de Janeiro, Brazil, were examined in this study. Hydrocarbon contamination was simulated in vitro, and the resulting microcosms were temporally analyzed (4, 12 and 32 days after contamination) using molecular methods. DNA and RNA extractions were followed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analyses and by the further molecular identification of selected DGGE bands. Archaeal communities could not be detected in the marine microcosms after contamination with the different hydrocarbons. In contrast, they were detected by DNA- and RNA-based methods in hypersaline water. Dendrogram analyses of PCR-DGGE showed that the archaeal communities in the hypersaline water-derived microcosms selected for by the addition of heptadecane, naphthalene or crude oil differed from the natural ones observed before the hydrocarbon contaminations. Principal coordinate analysis of the DGGE patterns showed an important effect of incubation time on the archaeal communities. A total of 103 DGGE bands were identified, and phylogenetic analysis showed that 84.4 % and 15.5 % of these sequences were associated with the Euryarchaeota and Crenarchaeota groups, respectively. Most of the sequences obtained were related to uncultivated archaea. Using redundancy analysis, the response of archaeal communities to the type of hydrocarbon contamination used could also be observed in the hypersaline water-derived microcosms.

Sorption–desorption behavior of the antibiotic tetracycline (TET) and the synthetic estrogen hormone 17α-ethinylestradiol (EE2) with wastewater sludge and sludge-derived humic substances [humic acid (HA) and humin] was investigated. From acidic functional group capacity and elemental analyses, HA had higher polarity, aromaticity, and acidity than humin; humin contained aliphatic chains with high mineral content. The different physicochemical properties of the pharmaceuticals and sludge components yielded different kinds of sorption–desorption interactions. Partitioning coefficients (Kd) of TET to sludge were higher (1,552 ± 41–4,667 ± 41 L/kg) than EE2 (534 ± 52–609 ± 47 L/kg). TET sorption was highly pH-dependent and maximal at pH 9. Ca²⁺ions enhanced sorption, emphasizing the role of polyvalent metal ions in forming TET–sludge complexes. Humin was the dominant component for TET sorption due to its high inorganic matter content. In contrast, EE2 sorption was independent of solution pH, forming mostly hydrophobic interactions with sludge organic matter. EE2 had a high affinity for HA due to its chemical structure. Desorption of the two pharmaceuticals differed as well. The amount of desorbed TET (18.7 ± 1.3–29.8 ± 2 %) was lower than that of EE2 (60.6 ± 3–62.3 ± 2 %), and the hysteresis index was higher for TET than EE2. While TET desorption tended to be delayed in the solid matrix, EE2 desorbed easily and in accordance with the aqueous equilibrium concentration. The conclusions emphasize the need for further research into frequently used pharmaceuticals with different physicochemical properties and the recognition of sludge application as an important source of distribution for these contaminants in the environment.

This is the first study that investigates in detail the effect of different sulfate concentrations on trichloroethene-dechlorinating microbial communities, both in terms of dechlorinating performance and microbial composition. The study used a series of Dehalococcoides-containing trichloroethene-dechlorinating microbial communities, which operated for more than 800 days in the presence of different sulfate concentrations and limiting-electron donor conditions. This study proves the ability of Dehalococcoides spp., the only genus able to completely dechlorinate trichloroethene, to predominate in mixed anaerobic microbial communities regardless of the magnitude of sulfate concentration, even under limiting-electron donor conditions. Although other microorganisms, such as the Sulfurospirillum spp. bacteria and members of the sulfate-reducing bacteria group were able to thrive, they were not able to predominate in such a competitive environment. However, this picture was not reflected in reductive dechlorination, which demonstrated a much better performance under methanogenic conditions or in the presence of low sulfate concentration (30 mg/l) than in the presence of higher sulfate concentrations (>400 mg/l). Therefore, different species of Dehalococcoides or other dechlorinating bacteria, which are not able to thrive in the presence of high sulfate concentrations (>400 mg/l), are possibly responsible for the higher dechlorination efficiency that was observed under methanogenic conditions.

The leachate pollution index (LPI) represents a tool to assess the pollution potential of a leachate, on a scale from 5 to 100. However, the significance of the LPI number in terms of a particular phytotoxic effect has not been investigated. The aim of this work was to determine if the LPI is also an appropriate tool in relation to the biological significance of a phytotoxic assay using the common bean plant (Phaseolus vulgaris L.) in a greenhouse scale test. Two different leachates were used in this study: one from Guanajuato (GUL) and another from Toluca (TOL); the calculated LPIs were 34.8 and 18.4, respectively. Leachate dilutions of 25, 50, and 75 % were used; undiluted leachate (100 %) was also used, and an enriched mineral solution was used as the control. Our findings indicate that when using concentrated leachate, the LPI was not directly related to the recorded phytotoxic effect (grain yield was significantly reduced by TOL leachate); however, when only using diluted leachate (25 %), the LPI was directly related to the effect. These findings suggest that for diluted leachates, leachates with higher LPIs are likely to exert a more detrimental effect on the common bean than leachates with lower LPIs.

Anthropogenic activities such as industry, agriculture, and daily life are related to metal pollution of the environment. Places known of the highest impact are fishponds where intensive fish farming is believed to input a significant amount of various elements to water. Additionally, many studies suspect wetland hunting activity of water lead pollution. The present paper aims to check if hunting is a significant source of lead (Pb) in water as well as to study the temporal trends of numerous parameters (pH, SEC, Cd, Cu, Zn, Ca, Mg, Na, K, NH4+, HCO₃⁻, SO₄²⁻, Cl⁻, NO₃⁻, F⁻) in ponds (n = 48) and inflow (n = 24) waters near Zator in southern Poland, Europe. Most concentrations were measured with ion chromatography and electrothermal atomic absorption spectrometry. Lead concentrations in pond waters were low and found not to be linked with hunting activity, as well as they did not differ from the ones found in the inflow water. Moreover, it could be stated that activities led on ponds did not enrich rivers in the studied ions and elements.

Activated natural siderite (ANS) was used to investigate its characteristics and mechanisms of As(V) adsorption from aqueous solution. Batch tests were carried out to determine effects of contact time, initial As(V) concentration, temperature, pH, background electrolyte, and coexisting anions on As(V) adsorption. Arsenic(V) adsorption on ANS well-fitted pseudo-second-order kinetics. ANS showed a high-adsorption capacity of 2.19 mg/g estimated from Langmuir isotherm at 25 °C. Thermodynamic studies indicated that As(V) adsorption on ANS was spontaneous, favorable, and endothermic. ANS adsorbed As(V) efficiently in a relatively wide pH range between 2.0 and 10.0, although the removal efficiency was slightly higher in acidic conditions than that in basic conditions. Effects of background electrolyte and coexisting anions were not significant within the concentration ranges observed in high As groundwater. Results of XRD and Fe K-edge XANES analysis suggested ANS acted as an Fe(II)/(III) hybrid system, which was quite effective in adsorbing As from aqueous solution. There was no As redox transformation during adsorption, although Fe(II) oxidation occurred in the system. Two infrared bands at 787 and 872 cm⁻¹after As(V) adsorption suggested that As(V) should be predominantly adsorbed on ANS via inner-sphere bidendate binuclear surface complexes.