Sericite, a mica-based natural clay was employed in the remediation of waters contaminated with two important heavy metal toxic ions, viz. Cd(II) and Mn(II), under batch and column experimentation. The batch reactor studies were intended to study various physicochemical parameters, viz. effect of sorptive pH, concentration, contact time, and background electrolyte concentrations which helped to deduce the mechanism involved at the solid/solution interface. The percent uptake of Cd(II) and Mn(II) was increased with increasing of the sorptive pH, and almost 100 % of these cations were removed at pH 10. Equilibrium-state sorption data was modeled and fitted well to the Langmuir and Freundlich adsorption isotherms. The kinetic data followed the pseudo-first-order and pseudo-second-order kinetic models. Increasing the background electrolyte concentrations by 100 times caused significant decrease of the uptake of Cd(II) and Mn(II) ions, which inferred that these metal cations were less adsorbed specifically and predominantly attached with relatively weak electrostatic attraction onto the solid surface. Additionally, the fixed-bed column reactor operations were also performed to assess the suitability of sericite in the attenuation of Cd(II) and Mn(II) from aqueous solutions under dynamic conditions. The breakthrough data obtained were successfully utilized to fit into a nonlinear fitting of Thomas equation. The results showed that the naturally and abundantly available sericite could be a potential natural material in the remediation of aquatic environment contaminated with Cd(II) and Mn(II).

The aim of the study was to estimate the impact of mechanical deweeding on the community structure of phytophilous macroinvertebrates. The eutrophic lake selected for the study was Dal Lake in the Kashmir Himalayas. The dissolved nutrient concentration was found to be highest in August and September, i.e., nitrates-nitrogen (513 μg l⁻ˡ) and total phosphorus (685 μg l⁻ˡ). During the period of investigation, a total of 22 macroinvertebrate taxa were recorded which belonged to phylum Arthropoda, Mollusca, and Annelida. The samples were collected with the help of a composite Gerking frame box and grappler. Mechanical deweeding had a profound impact on the population density of phylum Mollusca and Arthropoda followed by Annelida. However, family Tubificidae was not influenced by deweeding, as the harvester only trimmed the vegetation, and these organisms were recorded in the sediment of the lake. On average, the reference site had higher density of macroinvertebrates as compared to deweeded areas. The abundance of macroinvertebrates decreased from 200 ind. (individuals) m⁻²in the reference site to 51 ind. m⁻²in the deweeded site as a result of weed removal. Species richness and composition of major macroinvertebrates in harvested and unharvested areas of the lake were also dissimilar as portrayed by biotic indices vis-à-vis Shannon diversity index, evenness index, and Simpson index.

The objective of this study was to evaluate (qualitatively and quantitatively) the occurrence of antibiotic residue in pasteurized milk in Brazil. Pasteurized milk samples (n = 252) were collected monthly from Nov. 2010–Oct. 2011 from 21 commercial establishments (brands). A screening test (Delvotest® SP-NT) was applied to those samples. In positive (n = 19) and/or suspect samples (n = 24), we quantified oxytetracycline (OTC) and tetracycline (TC) by high-performance liquid chromatography with diode array detector (HPLC-DAD). OTCs were detected in all positive samples and TCs in six. In the 24suspected samples, OTCs were detected in 23 and TCs were not found in 8. Of the milk brands evaluated (n = 21), the presence of antibiotic residue was not detected in 4; in the other brands, both positive and suspect samples were verified. Results indicate the presence of antibiotic residue above legal limits. According to actual milk consumption in Brazil (441 mL/kg BW/day), in only 9 of the 17 brands of milk with antibiotic residue, the estimated daily intake was at or less than the maximum recommended by the European Union. The screening test used was effective to identify the presence of antibiotic residue (OTC and TC), confirmed by HPLC-DAD. The OTC is the predominant antimicrobial used by dairy farmers. Ingestion of contaminated milk by OTC and TC can increase the resistance of microorganisms to antibiotics.

Fish are bioindicators of water pollution, and an increased rate of their erythrocyte nuclear morphological abnormalities (ENMAs)—and particularly of erythrocyte micronuclei (EMN)—is used as a genotoxicity biomarker. Despite the potential value of ENMAs and MN, there is scarce information about fish captured in Iberian estuaries. This is the case of the Portuguese estuaries of the Mondego, Douro and Ave, suffering from different levels of environmental stress and where chemical surveys have been disclosing significant amounts of certain pollutants. So, the aim of this study was to evaluate genotoxicants impacts and infer about the exposure at those ecosystems, using the grey mullet (Mugil cephalus) as bioindicator and considering the type and frequency of nuclear abnormalities of erythrocytes as proxies of genotoxicity. Sampling of mullets was done throughout the year in the important Mondego, Douro and Ave River estuaries (centre and north-western Portugal). The fish (total n = 242) were caught in campaigns made in spring–summer and autumn–winter, using nets or fishing rods. The sampled mullets were comparable between locations in terms of the basic biometric parameters. Blood smears were stained with Diff-Quik to assess the frequencies of six types of ENMAs and MN (given per 1,000 erythrocytes). Some basic water physicochemical parameters were recorded to search for fluctuations matching the ENMAs. Overall, the most frequent nucleus abnormality was the polymorphic type, sequentially followed by the blebbed/lobed/notched, segmented, kidney shaped, vacuolated, MN and binucleated. The total average frequency of the ENMAs ranged from 73 ‰ in the Mondego to 108 ‰ in the Ave. The polymorphic type was typically ≥50 % of the total ENMAs, averaging about 51 ‰, when considering all three estuaries. The most serious lesion—the MN—in fish from Mondego and Douro had a similar frequency (≈0.38 ‰), which was significantly lower than that in the Ave (0.75 ‰). No significant seasonal differences existed as to the MN rates and seasonal differences existed almost only in the Douro, with the higher values in AW. In general, the pattern of ENMAs frequencies was unrelated with the water physicochemical parameters. Considering the data for both the total ENMAs and for each specific abnormality, and bearing in mind that values of MN in fish erythrocytes >0.3 ‰ usually reflect pollution by genotoxicants, it is suggested that mullets were likely being chronically exposed to such compounds, even in the allegedly less polluted ecosystem (Mondego). Moreover, data supported the following pollution exposure gradient: Mondego < Douro < Ave. The scenario and inferences nicely agree with the published data from chemical monitoring.

Copper (Cu) metabolism is altered in rats fed diets high in molybdenum (Mo) and low in Cu. This 10-week study was carried out to examine the effects of supplemental Mo (7.5–240 μg/g diet) on male Sprague–Dawley rats fed diets adequate in Cu (5 μg/g diet) and to determine the susceptibility of Mo-treated animals to the environmental pollutant 3,3′,4,4′-tetrabromobiphenyl (TBB). After 7 weeks of dietary treatment, half of the rats in each group received a single IP injection of TBB (150 μM/kg bw), while the other half received the corn oil vehicle. Rats sacrificed at 10 weeks showed no effects of Mo on growth, feed efficiency, or selected organ or tissue weights. Dose-dependent effects on plasma Mo (0–5.1 μg/mL), plasma Cu (0.95–0.20 μg/mL), and bone Cu (3.4–10 μg/g) in control through the high dose were found. Cu sequestration in the bone of Mo-treated rats is a new finding. TBB treatment resulted in dramatic weight loss and loss of absolute organ mass. Relative organ weights were increased, except for the thymus. TBB altered the concentrations of certain amino acids. Compared to control rats, this polybrominated biphenyl congener significantly decreased plasma Cu and ceruloplasmin at higher concentrations of dietary Mo and promoted the process of plasma Cu decrease by Mo, suggesting a combined effect.

Petroleum ether was used to extract petroleum hydrocarbons from soils collected from six oil fields with different history of exploratory and contamination. It was capable of fast removing 76–94 % of the total petroleum hydrocarbons including 25 alkanes (C₁₁–C₃₅) and 16 US EPA priority polycyclic aromatic hydrocarbons from soils at room temperature. The partial least squares analysis indicated that the solvent extraction efficiencies were positively correlated with soil organic matter, cation exchange capacity, moisture, pH, and sand content of soils, while negative effects were observed in the properties reflecting the molecular size (e.g., molecular weight and number of carbon atoms) and hydrophobicity (e.g., water solubility, octanol–water partition coefficient, soil organic carbon partition coefficient) of hydrocarbons. The high concentration of weathered crude oil at the order of 10⁵ mg kg⁻¹in this study was demonstrated adverse for solvent extraction by providing an obvious nonaqueous phase liquid phase for hydrocarbon sinking and increasing the sequestration of soluble hydrocarbons in the insoluble oil fractions during weathering. A full picture of the mass distribution and transport mechanism of petroleum contaminants in soils will ultimately require a variety of studies to gain insights into the dynamic interactions between environmental indicator hydrocarbons and their host oil matrix.

There is an increasing attempt in the world to determine the exposures of children to environmental chemicals. To analyze the genotoxic effect of air pollution, micronucleus (MN) assay was carried out in buccal epithelial cells (BECs) of children living in an urban city of Turkey. Children from two schools at urban-traffic and suburban sites were investigated in summer and winter seasons for the determination of BEC-MN frequency (per mille) and frequency of BEC with MN (per mille). The same children were also recruited for lung function measurements within a MATRA project (“Together Towards Clean Air in Eskisehir and Iskenderun”) Measured NO₂and SO₂concentrations did not exceed the European Union (EU) limit levels either in urban-traffic or suburban regions. Higher O₃concentrations were measured in the suburban site especially in the summer period. Particulate matter (PM₂.₅and PM₁₀) levels which did not differ statistically between two regions were above the EU limits in general. Although BEC-MN frequencies of children living in the suburban sites were higher in general, the difference between two regions was not significant either in the summer or winter periods. BEC-MN frequencies of the urban-traffic children were found to be significantly higher in summer period (mean ± SD, 2.68 ± 1.99) when compared to winter period (1.64 ± 1.59; p = 0.004). On the other hand, no seasonality was observed for the suburban children. Similar results have been obtained in the BEC frequency with MN in our study. In summer, BEC-MN frequencies were significantly increased with the decrease in pulmonary function levels based on forced expiratory flow between 25 and 75 % of vital capacity (FEF₂₅–₇₅ %) levels (p < 0.05). As a conclusion, children living in urban-traffic and suburban areas in the city of Eskişehir exhibited similar genotoxicity. Seasonal variation in genotoxicity may be interpreted as relatively high ozone levels and increasing time spent at outdoors in the summer.

Soils in urban areas are subjected to compaction with accelerating urbanization. The effects of anthropogenic compaction on urban soil denitrification are largely unknown. We conducted a study on an urban park soil to investigate how compaction impacts denitrification. By using¹⁵N labeling method and acetylene inhibition technique, we performed three coherent incubation experiments to quantify denitrification in compacted soil under both aerobic and anaerobic conditions. Uncompacted soil was set as the control treatment. When monitoring soil incubation without extra substrate, higher nitrous oxide (N₂O) flux and denitrification enzyme activity were observed in the compacted soil than in the uncompacted soil. In aerobic incubation with the addition of K¹⁵NO₃, N₂O production in the compacted soil reached 10.11 ng N h⁻¹ g⁻¹as compared to 0.02 ng N h⁻¹ g⁻¹in the uncompacted soil. Denitrification contributed 96 % of the emitted N₂O in the compacted soil and 36 % of the emitted N₂O in the uncompacted soil; total denitrification rate was higher in the compacted soil (up to 79.35 ng N h⁻¹ g⁻¹) than in the uncompacted soil (0.11 ng N h⁻¹ g⁻¹). Under anaerobic incubation with the addition of K¹⁵NO₃, no statistical difference in total N losses and¹⁵N-(N₂O+N₂) flux between the uncompacted soil and the compacted soil was detected. Compaction promoted soil denitrification and may impact urban N biogeochemical cycling.

Industrially contaminated sites with hazardous materials are a priority and urgent problem all over the world. Appropriate risk assessment is required to determine health risks associated with contaminated sites. The present study was conducted to investigate distribution of potentially hazardous, heavy metal (As, Cd, Cr, Cu, Ni, Pb and Zn) concentrations in surface and groundwater samples collected during summer (pre-monsoon) and winter (post-monsoon) seasons from an industrially contaminated site, Hyderabad, India, with potential source of metal contamination because of industrial effluents and usage of pesticides in agriculture. Heavy metal (HM) concentrations were analysed by using inductively coupled plasma-mass spectrometer and were compared with permissible limits set by the World Health Organisation. Data obtained was treated using multivariate statistical approaches like R-mode factor analysis (FA), principal component analysis, cluster analysis, geoaccumulation index, enrichment factor, contamination factor and the degree of contamination. Health risk assessment like chronic daily intake (CDI) and hazard quotient (HQ) were also calculated. Relatively high levels were noted in surface water with average concentrations during summer and winter seasons showing 16.13 and 11.83 for As, 7.91 and 1.64 for Cd, 88.33 and 32.90 for Cr, 58.11 and 28.26 for Cu, 53.62 and 69.96 for Ni, 173.8 and 118.6 for Pb, and 2,943 and 1,889 μg/L for Zn. While in groundwater, the mean metal levels during two seasons were 18.18 and 3.76 for As, 1.67 and 0.40 for Cd, 29.40 and 5.15 for Cr, 17.03 and 4.19 for Cu, 25.4 and 6.09 for Ni, 81.7 and 2.87 for Pb and 953 and 989 μg/L for Zn, respectively. FA identified two factors with cumulative loadings of F1—60.82 % and F2—76.55 % for pre-monsoon surface water and F1—48.75 % and F2—67.55 % for groundwater. Whereas, three factors with cumulative loadings of F1—39.13 %, F2—66.60 % and F3—81.01 % for post-monsoon surface water and F1—50.31 %, F2—66.18 % and F3—81.54 % for groundwater. The health risk assessment like CDI and HQ indices with increased levels of hazardous elements in the surface and groundwater were safe for drinking purposes provided some water treatment methodologies are adopted.

Rare earth element accumulation in the soil and elevated ultraviolet (UV)-B radiation (280–315 nm) are important environmental issues worldwide. To date, there have been no reports concerning the combined effects of lanthanum (La)(III) and elevated UV-B radiation on plant roots in regions where the two issues occur simultaneously. Here, the combined effects of La(III) and elevated UV-B radiation on the growth, biomass, ion absorption, activities, and membrane permeability of roots in soybean (Glycine max L.) seedlings were investigated. A 0.08 mmol L⁻¹La(III) treatment improved the root growth and biomass of soybean seedlings, while ion absorption, activities, and membrane permeability were obviously unchanged; a combined treatment with 0.08 mmol L⁻¹La(III) and elevated UV-B radiation (2.63/6.17 kJ m⁻² day⁻¹) exerted deleterious effects on the investigated indices. The deleterious effects were aggravated in the other combined treatments and were stronger than those of treatments with La(III) or elevated UV-B radiation alone. The combined treatment with 0.24/1.20 mmol L⁻¹La(III) and elevated UV-B radiation exerted synergistically deleterious effects on the growth, biomass, ion absorption, activities, and membrane permeability of roots in soybean seedlings. In addition, the deleterious effects of the combined treatment on the root growth were due to the inhibition of ion absorption induced by the changes in the root activity and membrane permeability.