Crosslinking carboxymethyl starch (CCMS) powder of degree of substitution (DS) 0.43–0.59 was prepared by the process of two steps of alkali addition synthesis. The technique of powder coupling with ultrafiltration was used to absorb Cu2+, Zn2+, Ni2+, Pb2+, and Cd2+ from aqueous solutions. FTIR was used to demonstrate the successfully grafting of carboxymethyl groups, and the technique of microwave plasma torch atomic emission spectrometer was applied in rapid determination of the aforementioned heavy metals ions. The results revealed that the removal sequence of heavy metal ions followed the order of Pb2+>Cu2+>Cd2+>Zn2+>Ni2+. By assistant of diethylene triamine penlaacetic acid, the quaternary system of Pb2+/Ni 2+/Cd2+/Cu2+ mixture solution could have the ideal separation. Besides, the influence of pH, ζ potential, DS value, and membranes molecular weight cut-off on removal of 20 mg L−1 Pb2+ or Ni2+ was also investigated.

Over a century of metal processing activity has resulted in widespread metal contamination of soils in Sudbury, ON, Canada. To assess the potential for recovery from the large reductions in metal deposition, critical loads were estimated for metals at 415 sites in Sudbury using an ‘effects based’ approach that is based on exceedance of provincial soil guidelines using multiple independent estimates of metal partitioning (Kd) for each metal. Sudbury soils are heavily contaminated with copper (Cu) and nickel (Ni), with 74 % of samples currently exceeding the provincial soil guideline for Cu and 87 % of samples exceeding the guideline for Ni. Both metals are strongly correlated with other metals (zinc (Zn), cadmium (Cd), lead (Pb)), although they rarely exceed provincial guidelines Copper and Ni are also strongly correlated with organic matter but not soil pH. Based on the most recent Cu and Ni deposition estimates (mid-1990s), it is estimated that between 20 % and 51 % of the sites receive deposition in excess of the ‘effects based’ critical load for Cu and between 5 % and 97 % of sites receive atmospheric deposition in excess of the ‘effects based’ critical load for Ni. These results suggest that Cu and Ni concentrations in soil will generally decrease resulting in slightly fewer sites that exceed the provincial soil guideline, but that the timeframe of this response will be very slow, with relatively little change occurring over the next 100 years. Even assuming a best case deposition scenario whereby Cu and Ni deposition were to immediately fall to background levels, the percentage of sites with Cu and Ni levels in excess of the OMOE guideline would still be between 69 % and 72 %, and 56 % and 86 %, respectively, demonstrating that while recovery of the Sudbury soils is possible, greater reductions in metal deposition are needed and even so, it will be a process that takes several centuries.

Total gaseous mercury (TGM) fluxes from the forest floor and a boreal wetland were measured by a flux chamber technique coupled with an automatic mercury vapour analyser. The fluxes were measured at three sampling sites in southern Finland, 61°14′ N, 25°04′ E in summer 2007, with additionally in situ TGM concentrations in the air at one of the sites and mercury bulk deposition at another. Most of the flux data were collected during the daytime. At one of the sites, diurnal flux behaviour was studied, and a clear cycle with an afternoon maximum and a night minimum was observed. The highest emissions (up to 3.5 ng m−2 h−1) were observed at the forest floor site having a moss and grass cover. At the wetland and litter-rich forest floor sites, the emissions were below 1 ng m−2 h−1 and sometimes negative (down to −1.0 ng m−2 h−1), indicating mercury uptake. The measured average fluxes in August were 0.9 ± 1.1 and 0.2 ± 0.3 ng m−2 h−1 for the forest floor sites and wetland sites, respectively. The flux data were compared with the mercury bulk deposition, which proved to be of the same magnitude, but opposite in sign. At the mossy forest floor site, the extrapolated TGM emissions were 130% of the Hg deposition in August 2007. Comparison with other studies showed that the fluxes in background areas are relatively uniform, regardless of measurement site location and method used. Airborne TGM remained at the background level during the study, with an average value of 1.3 ± 0.2 ng m−3; it frequently showed a diurnal cycle pattern.

In this work, the electrochemical treatment of an effluent from the pharmaceutical industry with boron-doped diamond electrodes was investigated. The electrolyses were carried out in a discontinuous operation mode under galvanostatic conditions, using a bench-scale plant equipped with a single-compartment electrochemical flow cell. The effect of operating conditions, such as current density (from 25.7 to 179.4 mA cm2) and flow rate (from 104.8 to 564.7 cm3 min−1), at residence times between 0 and 570 min, was studied. Design of experiments was used for optimizing the process. The global contribution of operative parameters and evolution of the residence time in TOC removal was studied, and a time of 77 min was obtained in order to evaluate the highest influence of the operative parameters. For this time, ANOVA test reported significance for four of the five involved variables. The current density was found to have a considerable positive effect on TOC removal, whereas the flow rate was found to have a moderate negative effect on target variable.

Energy intake and allocation are mainly used to maintain body functions, such as locomotion, growth, and reproductive output. It has been observed that environmental pollutants can affect the energy allocation either due to a cost of handling toxicants or because the toxicant interacts with the storage processes within the organisms. Less than a handful of studies are available reporting the effect of toxicants on energy reserves in enchytraeids and no studies have dealt with the influence of nanomaterials. The present paper shows results on the basal energy reserves (lipids, carbohydrates, and proteins) in Enchytraeus albidus and the influence of copper (Cu) salt and Cu nanoparticles on these reserves for two exposure durations. The energy allocation levels follow what has been reported for other worm species, although lower carbohydrate levels were observed. There were clear differences between worms exposed to control soils and those exposed to Cu for 3 weeks, but no difference after 6 weeks exposure. There was no apparent difference between the impacts of the two Cu exposure forms.

Agricultural runoff containing nitrogen fertilizer is a major contributor to eutrophication in aquatic systems. One method of decreasing amounts of nitrogen entering rivers or lakes is the transport of runoff through vegetated drainage ditches. Vegetated drainage ditches can enhance the mitigation of nutrients from runoff; however, the efficiency of nitrogen removal can vary between plant species. The efficiency of three aquatic macrophytes, cutgrass (Leersia oryzoides), cattail (Typha latifolia), and bur-reed (Sparganium americanum), to mitigate dissolved and total nitrogen from water was investigated. Replicate mesocosms of each plant species were exposed to flowing water enriched with ammonium and nitrate for 6 h, allowed to remain stagnant for 42 h, and then flushed with non-enriched water for an additional 6 h to simulate a second storm event. After termination of the final simulated runoff, all vegetated treatments lowered total nitrogen loads exiting mesocosms by greater than 50%, significantly more than unvegetated controls, which only decreased concentrations by 26.9% (p ≤ 0.0023). L. oryzoides and T. latifolia were more efficient at lowering dissolved nitrogen, decreasing ammonium by 42 ± 9% and 59 ± 4% and nitrate by 67 ± 6% and 64 ± 7%, respectively. All treatments decreased ammonium and nitrate concentrations within mesocosms by more than 86% after 1 week. However, T. latifolia and L. oryzoides absorbed nitrogen more rapidly, lowering concentrations by greater than 98% within 48 h. By determining the nitrogen mitigation efficiency of different vegetative species, plant communities in agricultural drainage ditches can be managed to significantly increase their remediation potential.

The present study evaluated the short-term toxicity of seven selected pesticides: four insecticides (chlorpyrifos, dieldrin, diazinon and pirimiphos-methyl) and three herbicides (diuron, alachlor and atrazine). With this aim, a standard toxicity test with the highly sensitive early life stages (ELS) of a marine fish was used. The turbot, Psetta maxima, is abundant in shallow estuarine and costal habitats and is currently the most commonly cultivated fish species in Galicia, NW Spain. According to the turbot ELS test results, chlorpyrifos was the most toxic pesticide tested for both embryos and larvae and was followed in order of decreasing toxicity by dieldrin, pirimiphos-methyl, diazinon, alachlor, atrazine and diuron. Larvae were more sensitive than embryos to the seven pesticides. The median lethal concentrations of the selected pesticides during a 48- and a 96-h exposure for turbot embryos and larvae were, respectively (in micrograms per litre): chlorpyrifos, 116.6 and 94.65; dieldrin, 146 and 97; pirimiphos-methyl, 560 and 452; diazinon, 1,837 and 1,230; alachlor, 2,177 and 2,233; diuron, 10,076 and 7,826; and atrazine, 11,873 and 9,957. According to their acute toxicity, the insecticides were more toxic than the herbicides. Furthermore, all insecticides and herbicides appear to be teratogenic to turbot ELS.

This study assessed the efficiency of sewage treatment plants (STPs) in removing sterols based on chemical analyses of both influents and effluents. Samples from 3s and three tertiary plants were collected and analyzed by gas chromatography mass spectrometry for 23 individual sterols including mestranol, norethindrone, equol, estrone, equilin, norgestrel, 17α-ethinylestradiol, 17α-estradiol, 17β-estradiol, estriol, dihydrocholesterol (cholestanol), coprostanol, epicoprostanol, cholesterol, desmosterol, campesterol, stigmasterol, β-sitosterol, coprostanone, cholestanone, epicholestanol, stigmastanol, and 24-ethylcoprostanol. The percentage of sterols remaining in effluent samples (compared to influent samples) ranged from 0% to 80% and varied among sterol compounds and with STP location and treatment type. Differences in the efficiency of sterol removal for secondary and tertiary STPs were statistically significant. Although the concentration of sterol compounds differed between influents and effluents, sterol abundances remained the same. The most abundant sterol detected was cholesterol, followed by the fecal sterol coprostanol, and the plant sterols 24-ethylcoprostanol and β-sitosterol. For three STPs, the hormone estrone was detected in effluents at concentrations of 0.03–0.05 μg L−1. Ten sterol ratios specific for human fecal contamination and eight sterol ratios for differentiating among multiple sources of fecal contamination were calculated and showed that 12 ratios for influent and nine ratios for effluent were successful for human fecal source tracking. Based on sterol ratio values in this study, new criteria for identification of human fecal contamination were suggested.

The upper limit of fluoride concentration in water for human consumption is 1.5 ppm. Many studies have been carried out concerning the water fluoride concentration in wide areas around the world, but none have studied the change of fluoride concentration as a function of geographical coordinates and through time. This paper describes ‘microvariation’ of fluoride concentration among wells separated by less than 500 m in a month. On the other hand, ‘macrovariation’ is also studied describing changes among cities that are separated by more than 10 km and compared with fluoride concentrations measured 65 years ago. Fluoride concentration was measured in a wide geographical area of Argentina, which is 133,000 km². Samples of water were collected from different regions. Macrovariation: Differences in fluoride concentration in well water among regions were found, as well as an increase in water fluoride concentration during seven decades. Microvariation: Daily water fluoride concentration in a specific area displayed a great variation in the measurements through time. In addition, wells with no more than 500 m of separation were measured at the same time and were significantly different. These results indicate that in order to determine the fluoride concentration of a region, different samples of the same area should be obtained and a sampling through time should also be done.

In domestic wastewater, bacterial physiology controls cell production (growth, replication) and cell maintenance, determining how energy is allocated between these two processes. The aim here was to develop a method to quantify these cellular processes so that the bacterial physiological state could be manipulated to lower this source of pollution. We simultaneously used the incorporation of radiolabelled thymidine into DNA (a measure of new cell synthesis) and leucine into protein in wastewater to quantitatively distinguish bacterial growth from maintenance processes. We found that DNA and protein syntheses were coupled in wastewater after substrate enrichment (with glucose or acetate)—balanced growth. Once the substrate was depleted, the two processes became uncoupled—unbalanced growth. In this physiological state, the bacteria were synthesising protein, but fewer bacteria were replicating. More energy was allocated to cell maintenance than replication. A mean Leu/TdR ratio of 7.4 was determined for wastewater and was similar to natural aquatic ecosystems. As the bacterial growth rate decreased, the Leu/TdR ratios increased. We show how the simultaneous measurement of [³H]Leu and [³H]TdR quantitatively distinguishes balanced from unbalanced growth. Low [³H]Leu/[³H]TdR ratios indicated bacteria were physiologically stressed, an ideal state for biological wastewater treatment processes (WWTP) as the bacteria divert more energy to maintenance activities instead of growth. Leu/TdR ratios of 70 have been recorded in natural aquatic ecosystems which suggests WWTP have potential to be manipulated to achieve much higher Leu/TdR ratios than we report here. Changes to plant operation to improve operation efficiency include finding the optimum rate of substrate (pollution supply) or alternating aerobic and anaerobic periods to maximise the Leu/TdR ratio to achieve less biomass production for land disposal and more cost-effective operation that generates less pollution in the effluent.