The kinetics and mechanism of methylene blue adsorption onto raw pine cone biomass (Pinus radiata) was investigated under various physicochemical parameters. The extent of the methylene blue dye adsorption increased with increases in initial dye concentration, contact time and solution pH but decreases with the amount of adsorbent, salt concentration and temperature of the system. Overall the kinetic studies showed that the methylene blue adsorption process followed pseudo-second-order kinetics among various kinetic models tested. The different kinetic parameters including rate constant, half-adsorption time and diffusion coefficient are determined at different physicochemical conditions. Equilibrium data were best represented by Langmuir isotherm among Langmuir and Freundlich adsorption isotherm. The maximum monolayer adsorption capacity of pine cone biomass was 109.89 mg/g at 30°C. The value of separation factor, R L, from Langmuir equation and Freundlich constant, n, both give an indication of favourable adsorption. Thermodynamic parameters such as standard Gibbs free energy (∆G 0), standard enthalpy (∆H 0), standard entropy (∆S 0) and the activation energy (A) were calculated. A single-stage batch absorber design for the methylene blue adsorption onto pine cone biomass has been presented based on the Langmuir isotherm model equation.

The use of sewage mud in agriculture has generated several discussions due to the risks of soil contamination mainly by metals. Due to the intimate contact of the diplopods with soil, they have been successfully used in ecotoxicological analyses. The impact of the external environment in the physiological changes in organs and tissues of different organisms can be reflected by the ultrastructural changes of their cells. Using the transmission electron microscopy, this study aimed to analyze the ultrastructural alterations in the midgut of the diplopod Rhinocricus padbergi exposed to substrate containing sewage mud from a Sewage Treatment Station of São Paulo State, Brazil. Therefore, it was sought to identify cellular alterations resulting from the subchronic exposure (90 days of exposure) of the animals to complex and potentially toxic mixtures such as sewage mud at different concentrations (1%, 10%, and 50%). The control group presented integrity in the cells and tissues that constitute the midgut. The animals exposed to sewage mud at 10% and 50% died before the 90 days of exposure. The analysis of the midgut of the animals exposed to 1% of sewage mud showed alterations in the epithelial cells, cells of the fat body layer, and hepatic cells. The main alterations observed were cytoplasmatic vacuolization, loss of the plasmatic membrane, and nuclear envelope integrity. We conclude that the mud sample presents a mixture of complex substances of cytotoxic and genotoxic action to the diplopod, causing cell death, since both the nucleus and other cellular compartments were damaged.

Hydroponic and pot experiments were conducted to assess the uptake of heavy metals (Cd and Zn) by a common crop plant, African basil, Ocimum gratissimum. In addition, the effects of soil amendments, hydroxyapatite (HA) and cow manure on plant growth and metal accumulations were compared. In the hydroponic study, plants were exposed to various concentrations of Cd (2.5 and 5 mg L⁻¹) and Zn (10 and 20 mg L⁻¹) for 15 days. O. gratissimum was shown to be a Cd accumulator more than a Zn accumulator. Cadmium concentration in its shoots exceeded 100 mg kg⁻¹. In the pot experiments, soils from a heavily Cd-contaminated site (Cd 67.9 mg kg⁻¹ and Zn 2,886.8 mg kg⁻¹) were treated with cow manure and HA at the rates of 10% and 20% (w/w), and 0.75 and 1.5% (w/w), respectively. Plants were grown in the greenhouse for 3 months. The addition of cow manure resulted in the highest biomass production and the lowest accumulations of Cd in plant parts, while HA was more efficient than cow manure in reducing Zn uptake. Leaves of African basil showed a decreased Cd concentration from 1.5 to 0.3 mg kg⁻¹ (cow manure) and decreased Zn concentration from 69.3 to 34 mg kg⁻¹ (HA). This clearly demonstrates the efficiency of HA and cow manure in reducing metal content in leaves of plants grown on high metal-contaminated soil to acceptable or close to acceptable values (0.2 mg kg⁻¹ for Cd, 99.4 mg kg⁻¹ for Zn).

Limnologists have regarded temporal coherence (synchrony) as a powerful tool for identifying the relative importance of local-scale regulators and regional climatic drivers on lake ecosystems. Limnological studies on Asian reservoirs have emphasized that climate and hydrology under the influences of monsoon are dominant factors regulating seasonal patterns of lake trophic status; yet, little is known of synchrony or asynchrony of trophic status in the single reservoir ecosystem. Based on monthly monitoring data of chlorophyll a, transparency, nutrients, and nonvolatile suspended solids (NVSS) during 1-year period, the present study evaluated temporal coherence to test whether local-scale regulators disturb the seasonal dynamics of trophic state indices (TSI) in a giant dendritic reservoir, China (Three Gorges Reservoir, TGR). Reservoir-wide coherences for TSICHL, TSISD, and TSITP showed dramatic variations over spatial scale, indicating temporal asynchrony of trophic status. Following the concept of TSI differences, algal productivity in the mainstream of TGR and Xiangxi Bay except the upstream of the bay were always limited by nonalgal turbidity (TSICHL−TSISD <0) rather than nitrogen and phosphorus (TSICHL−TSITN <0 and TSICHL−TSITP <0). The coherence analysis for TSI differences showed that local processes of Xiangxi Bay were the main responsible for local asynchrony of nonalgal turbidity limitation levels. Regression analysis further proved that local temporal asynchrony for TSISD and nonalgal turbidity limitation levels were regulated by local dynamics of NVSS, rather than geographical distance. The implications of the present study are to emphasize that the results of trophic status obtained from a single environment (reservoir mainstream) cannot be extrapolated to other environments (tributary bay) in a way that would allow its use as a sentinel site.

Since the beginning of the twentieth century, the province of Castellón, in eastern Spain, has been one of the most important areas of floor and wall tile production on both a national and worldwide scale. As a result of this sector’s productive rate of development (in the 1970–2005 interval), a series of pollution-producing chemical substances has been introduced into the atmosphere. The objective of this study is the comparison between industrial–urban and rural zones in this province, with the goal of establishing the causes of the contamination in order to apply corrective measures upon the different emission sources. Sustainable development is sought after to guarantee that, in the future, the environmental quality parameters fall within legal limits, ensuring the population’s well-being as well as conserving natural ecosystems and material assets. Total suspended particles and PM10 are the parameters studied. The reason for choosing this pollutant type is because particulate matter may present a much higher potential risk despite its low representativeness as compared to the gas pollutant’s group. A positive correlation between high particle concentrations and deterioration in public health has been shown in recent studies. The elements As, Cd, Ni, and Pb in PM10 were also analyzed to determine the toxicity of these particles. This study has demonstrated the different behaviors of the parameters studied at different types of stations (industrial–urban and rural), leading to the conclusion that anthropogenic factors are very important in the area studied and that they determine the area’s air quality to a great extent.

The goal of the present work was to increase our knowledge on the behavior of manganese and nickel in soil within a Mediterranean environment. The study assessed the concentration levels of Mn and Ni (heavy metals selected for their essential role in the development of plants) in 250 soil horizon samples within 125 soil profiles of undisturbed soils in La Rioja (Spain). The study was undertaken to investigate and predict Mn and Ni concentrations on a regional scale. The analysis of spatial distribution of the elements was found to be affected by the nature of bedrock and, to a lesser extent, the anthropogenic origin. The variation of vertical distributions can be related, first, to natural sources—mainly the bed rocks—and, second, to soil processes. The geographical distribution of soil Mn is important to agriculture, nutrition, and health. Soil Mn and Ni maps of the area were elaborated, using geostatistics and geographic information systems. Mapping of geographical distributions will be useful in future research to determine regional patterns of Mn and Ni bioavailability, Mn and Ni deficiencies, and the possible consequences of land disposal of Mn- and Ni-laden wastes.

Medicines and their metabolites have been found as water contaminants at very low concentrations; moreover, there is no extensive toxicological data to determine the risks associated with their occurrence in water resources. The ibuprofen genotoxicity potential to the Oreochromis niloticus fish (Tilapia), due to nanograms per liter exposure, was evaluated using the micronucleus test. Acute (48 h) and sub-chronic assays (10 days) were carried out at 300 ng/L ibuprofen aquatic concentration comparing with the negative control group (without treatment), with eight animals per group. The results were assessed from the average of triplicate analyses. The micronucleus frequency in peripheral blood of fish was determined using a sample size of 3,000 erythrocytes per animal. Significance was defined using t test (p ≤ 0.05). The bioassay results showed a statistically significant increase in the frequency of micronuclei for both exposure times in comparison to the negative control. The micronucleus frequency observed for the sub-chronic tests was higher than the one identified in the acute assays. The observed ibuprofen genotoxic effects demonstrated an aquatic environmental risk of this pharmaceutical, which occurs for the used fish experimental model in lower concentration than previously described for other aquatic organisms.

Soils are an important sink for persistent organic pollutants (POPs), and high mountain soils are considered a stable reservoir for many compounds due to their high organic matter content. This study focuses on the small-scale variability on the environmental distribution of dichlorodiphenyltrichloroethane (DDT) in mountain soils. Several soil samples taken from May 2007 to June 2008 in a small area at around 1,900 m a.s.l. (Italian Central Alps) were analyzed for DDT compounds. Pedological analyses were done as well. Organic matter content, soil layer, differences in solar radiation, and sampling period were considered as possible variability factors. Organic matter content can account for a DDT concentration difference of a factor 3 among different sites, soil layer can account for a concentration difference of a factor near 2, differences in solar radiation values do not seem to affect DDT concentrations, whereas the sampling period has the greatest influence with a difference factor of three to four among different sampling dates. Summing all these variability factors together, even though operating on such a small scale, we obtain a predicted spatial variability depending on the considered variables near to one order of magnitude. In particular, it was surprising that seasonal variations could be so great. If this conclusion is to be confirmed in the future, this element must be considered very carefully by scientists and environmental agencies during monitoring campaigns.

Two greenhouse pot experiments were conducted in Agrinion, Greece, using a randomized block design in four replications, respectively, as follows: The first one included five levels of treated municipal wastewater (TMWW), being used as an irrigation water source. The second one, five levels of applied Cl at a constant soil applied Cd level of 10.36 mg/kg soil, the plants being irrigated with fresh well water. The purpose of these experiments was to study the impact of the Cl × Cd interrelationship on planning TMWW reuse, for the irrigation of Brassica oleracea var. Capitata (cabbage) cv F1 Gloria, ehich was used as test plant, in both of these experiments. It was found that the TMWW Cl content, originating mainly from the procedure of wastewater chlorination, was synergistically interrelated with the toxic heavy metal Cd, increasing its soil availability and cabbage plant leaf uptake (edible plant part). As this increase is directly associated with the consumer's health, it was suggested that the TMWW be subjected to dechlorination process or the disinfection be made by ozonation or UV, which do not include Cl.

Sediment cores were analysed from four coastal wetland sites within the Minas Basin, Bay of Fundy to compare mercury speciation and sediment characteristics. The coastal wetland sediments were low in total mercury (mean = 17.4 ± 9.9 ng g−1); however, MeHg concentration was 92 times higher (mean of 249 pg g−1) than intertidal mudflat sediment (mean of 2.7 pg g−1). Total mercury concentrations in intertidal mudflat cores were also low (0.5–23.7 ng g−1) and correlated (Pearson correlation = 0.98; p < 0.01) with % organic carbon; with low concentrations of MeHg present only below depths of 6 cm (mean = 2.7 ± 1.0 pg g−1). Total mercury concentrations were negatively correlated (correlation = 0.56, p < 0.05) with inorganic sulphur (acid volatile sulphides (AVS) and pyrite) while MeHg concentrations were inversely correlated (Pearson correlation = −0.68; p < 0.05) with the pyrite content but not with AVS. Methyl mercury concentrations were not significantly correlated with organic carbon content in the wetland sediments, and mercury-in-biomass enrichment factors were lower (total mercury mean 1.5 ± 1.9 and MeHg mean = 3.6 ± 4.8) than published measurements from mercury polluted sites. Modelling estimates found on average 4.4 times more total mercury mass in the intertidal mudflat sediments relative to vegetated wetlands. A negative relationship was observed between MeHg concentrations (below 20 cm depth) and modelled tidal inundation. The mineral fraction within wetland sediments contained 96.2% of the total mercury mass; however, the highest concentrations of mercury species were in root biomass. This research confirms that vegetated coastal wetlands are key areas for formation of bioavailable methyl mercury, and mercury distribution is tied to organic carbon and sulphur speciation.