Analytical measurements are commonly used to screen for toxicity or lack of toxicity from sediment-associated copper. Comparisons of analytical measurements with toxicological responses can be useful for determining the practicality of analytical measurements for assessing the toxicity of copper in sediments. The purpose of this research was to determine the utility of method detection limits (MDLs; i.e., minimum concentration of an analyte such as copper that can be measured with 99 % confidence with a specific analytical method and matrix) to predict the bioavailability of copper in five different sediments. The specific objectives of this research were to (1) select and characterize five sediments with different characteristics, (2) amend and measure a range of copper concentrations in the five sediments to determine MDLs and bioavailability of copper amendments in those sediments, (3) discern relationships with sediment characteristics to MDLs and bioavailability of copper in the five sediments, and (4) compare MDLs and observed toxicity to Hyalella azteca Saussure as an indicator of copper bioavailability in the five sediments. The lowest copper concentrations that elicited an observable adverse effect ranged from 15 to 550 mg Cu/kg, and the MDLs ranged from 1.5 to 6 mg Cu/kg. The MDLs and measured copper concentrations were not adequately predictive of the bioavailability and toxicity of copper in the five sediments. No adverse effects were observed for H. azteca exposed for 10 days to the sediment from California with simultaneously extractable metals > acid-volatile sulfides. Since the lowest observed effects concentrations of copper in the five sediments ranged two orders of magnitude, the National Oceanic and Atmospheric Administration screening values (threshold and probable effect levels) were not predictive of H. azteca responses to the copper-amended sediments.

Remediation of anthracene from soil was faster in the topsoil than in the lower layers. It was not clear whether this was due to a higher anthracene bioavailability or an increased microbial degradation in the topsoil layer. Therefore, an arable soil was contaminated with 500 mg anthracene kg⁻¹ dry soil, and its removal was monitored with an exhaustive technique and with n-butanol to determine its bioavailability in three layers. Additionally, part of the contaminated soil was stored aerobically for 112 days (considered the aged soil), and the anthracene was monitored thereafter. After 112 days, 360 mg anthracene kg⁻¹ was removed from the soil, but its dissipation was not affected by the layer, depth, and fluctuations in water content or the interaction between. In the aged soil stored for 112 days, only 170 mg anthracene kg⁻¹ was removed. In the subsequent incubation of the aged soil, 273 mg anthracene kg⁻¹ was removed within 28 days, and after 112 days, no contaminant was detectable in the soil. An additional experiment confirmed the hypothesis that simply mixing the soil accelerated the removal of anthracene. Mixing the soil every 7 days removed all anthracene from the soil within 28 days, while in the undisturbed soil, 301 mg anthracene kg⁻¹ was still extractable. It can be concluded that mixing the soil accelerated the removal of anthracene, but fluctuations in water content did not. The anthracene extracted with n-butanol was not related to the amount removed and is thus not a good indicator of bioavailability of anthracene in soil.

Input/output budgets for cadmium (Cd), lead (Pb) and mercury (Hg) in the years 1997–2011 were monitored and determined for 14 small forest-covered catchments across Europe as part of the Integrated Monitoring program on the effects of long-range pollutants on ecosystems. Metal inputs were considered to derive from bulk deposition, throughfall and litterfall. Outputs were estimated from run-off values. Litterfall plus throughfall was taken as a measure of the total deposition of Pb and Hg (wet + dry) on the basis of evidence suggesting that, for these metals, internal circulation is negligible. The same is not true for Cd. Excluding a few sites with high discharge, between 74 and 94 % of the input Pb was retained within the catchments; significant Cd retention was also observed. High losses of Pb (>1.4 mg m⁻² year⁻¹) and Cd (>0.15 mg m⁻² year⁻¹) were observed in two mountainous Central European sites with high water discharge. All other sites had outputs below or equal to 0.36 and 0.06 mg m⁻² year⁻¹, respectively, for the two metals. Almost complete retention of Hg, 86–99 % of input, was reported in the Swedish sites. These high levels of metal retention were maintained even in the face of recent dramatic reductions in pollutant loads.

Emissions of volatile organic compounds (VOCs) were studied from three heavily polluted rivers (Huijiang, Nancun, and Zengbian Rivers) in Guangzhou, South China. A total of 49 species of VOCs were identified. Nancun River had the highest concentration of total VOCs (TVOCs), which ranged from 1,467 to 5,522 μg m⁻³. Trichloroethene, benzene, toluene, ethylbenzene, m/p-xylene, o-xylene, styrene, and 1,3,5-trimethylbenzene were the main pollutants. The levels of VOCs evaporated from the three rivers exhibited different patterns. Correlations between the concentrations of major VOCs were established and found to be statistically significant, except for o-xylene. The ratios of toluene/benzene, ethylbenzene/benzene, and xylene/benzene were estimated and found to be higher than widely reported in the literature. TVOC fluxes in the three rivers were calculated to be the range from 24.8 to 765 μg m⁻² h⁻¹. This study provides a regional background for the emission inventories of VOCs from heavily polluted rivers in southern China and provides resource managers with important information to guide remediation and policy concerning VOC emissions to the environment.

It is known that peat can be a potential adsorbent to remove contaminants from wastewaters. When raw peat is used, many limitations exist: Natural peat has a low mechanical strength, high affinity for water, poor chemical stability and tendency to shrink and/or swell. In this work, in order to obtain a more manageable substrate, to be used as adsorbent, peat was entrapped in calcium alginate beads. Box–Behnken factorial design was used to obtain the best condition for the immobilization of peat in calcium alginate beads. The independent variables studied were: peat concentration, sodium alginate concentration and calcium chloride concentration, whereas the dependent variables studied were based on the variation of colour parameters after the treatment of vinasses with entrapped peat. High colour reductions can be achieved using entrapped peat formulated by mixing 2 % of peat with 3 % of sodium alginate and pumped it on calcium chloride (0.05 M).

Water and sediment samples were collected along river transects at three artisanal gold mining areas in southern Ecuador: Nambija, Portovelo-Zaruma, and Ponce Enriquez. Samples were analyzed for a suite of major and trace elements, including filtered/unfiltered water samples and stream flow measurements to determine dissolved/particulate loads. Results show that the Q. Calixto, Calera, and Siete rivers (corresponding to Nambija, Portovelo-Zaruma, and Ponce Enriquez mining areas, respectively) have substantial trace element contamination due to mining inputs. Dissolved concentrations were elevated at Calera and Siete relative to Q. Calixto, possibly reflecting the input of soluble cyano-metal complexes in mining zones where cyanidation is used in ore processing. A negative correlation was found between MeHg:THg ratios and pH, indicating an inverse relationship of mercury methylation with cyanidation (since cyanidation increases water pH). This was the first comprehensive study to examine an extensive suite of trace elements in both water and sediment at the three main gold mining areas of southern Ecuador, including dissolved and particulate loads, and the first study to report MeHg concentrations in the mercury-contaminated rivers.

This paper addresses the oxidation by ultraviolet radiation of methylparaben, a ubiquitous and suspicious preservative which is massively added to cosmetics and personal care products. Experiments included pH and temperature variation, as well as several experimental conditions such as presence/absence of hydrogen peroxide, titanium dioxide, or some different water matrix (surface water or ground water). Results were evaluated under the line source spherical emission model, so quantum yield was the adequate target variable for explaining the process. A modified Arrhenius correlation including pH level was used for modelling the whole system.