Effect of compost and manure amendments on zinc soil speciation, plant content, and translocation in an artificially contaminated soil

The addition of organic matter in soil can modify the bioavailability of heavy metals. A greenhouse pot experiment was carried out using an edible plant species Eruca vesicaria L. Cavalieri grown on an artificially contaminated soil with Zn (665 mg?kg^?1). In this study, the effect of compost at 20 t?ha^?1 (C20) and at 60 t?ha^?1 (C60), manure at 10 t?ha^?1 (M10) and at 30 t?ha^?1 (M30), and chemical fertilizers (NPK) on Zn fate in a soil–plant system was evaluated. At the end of the experiment, the main growth parameters and Zn content in plants were determined. In addition, Zn speciation in the soil was assessed using the original Community Bureau of Reference sequential extraction and diethylene triamine pentaacetic acid extraction. Zinc, though an essential element for plant growth, caused toxicity effects in plants grown on control and manure treatments, while in the compost treatments, plants showed no visual toxicity symptoms. The concentrations of Zn in roots were similar for all treatments, while significant differences were observed for shoots. In fact, in the compost treatments, plants showed the lowest Zn concentration in shoots. Zinc speciation seems not to be affected by the applied treatments. Indeed, Zn plant content and translocation to shoots seems to be affected. Compost amendments significantly reduced Zn content and translocation in comparison to other treatments.     

Sustainable graywater reuse for residential landscape irrigation – a critical review

The demand for potable water is rising rapidly due to an ever-increasing population, economic activities, and dwindling water supplies. To provide adequate water supplies in the future, understanding the issues and challenges in the reuse of water and developing appropriate strategies for reuse will be critical. One way to augment water supplies for residential use is to reuse graywater – the wastewater from kitchens, bathrooms, and laundries. In this article, we critically review the evolution of water reuse, the definition of graywater, graywater reuse practices, volumes and flow in different situations, and graywater characteristics. We then examine the issues associated with different graywater treatment methods and how using graywater for irrigation around homes affects soil quality and plant growth. The study concludes that graywater treatment costs, human health risks, and its effect on soil quality are some of the challenges that need to be addressed in the future for widespread and sustainable reuse of graywater for irrigation around homes.     

Simulation and life cycle assessment of process design alternatives for biodiesel production from waste vegetable oils

This study uses the process simulator ASPEN Plus^® and Life Cycle Assessment (LCA) to compare three process design alternatives for biodiesel production from waste vegetable oils that are: the conventional alkali-catalyzed process including a free fatty acids (FFAs) pre-treatment, the acid-catalyzed process, and the supercritical methanol process using propane as co-solvent. Results show that the supercritical methanol process using propane as co-solvent is the most environmentally favorable alternative. Its smaller steam consumption in comparison with the other process design alternatives leads to a lower contribution to the potential environmental impacts (PEI’s). The acid-catalyzed process generally shows the highest PEI’s, in particular due to the high energy requirements associated with methanol recovery operations.     

EGG PRODUCTION AND HATCHING SUCCESS IN NORTH ADRIATIC SEA POPULATIONS OF THE COPEPOD Acartia clausi

Egg production, fecal pellet production and hatching success are reported for Acartia clausi females sampled during three cruises in February 1997, 1998 and June 1997 at 20-24 stations along 4 transects in the North Adriatic Sea. Dramatically low hatching rates were recorded during both diatom bloom events in February as opposed to much higher rates during post-bloom conditions in June, even though A. clausi productivity during the bloom was apparently high. These results are discussed in the light of recent findings on the negative impact of diatoms on copepod reproductive potential.     

Sediment preferences and oil contamination in the Pacific sand lance Ammodytes hexapterus

Sand lance, Ammodytes hexapterus Pallas, forage for zooplankton in the water column and are under heavy predation from fish, marine birds and marine mammals. To avoid predation, these fish bury themselves in soft bottom sediments when not foraging and during overwintering. We collected sand lance in Sequim Bay, Washington State, USA, in 1982. In three experiments we presented the fish with: (1) four different sediment types (fine sand, coarse sand, gravel, silt) to determine their sediment preferences; (2) clean and oil-contaminated preferred sediment to determine whether the fish would avoid the contamination; and (3) clean unpreferred and oil-contaminated preferred sediment to determine whether the contamination would alter their sediment preferences. In the first experiment, sand lance preferred to bury in fine and coarse sands and avoided gravel and silt. In the second experiment, sand lance avoided sand contaminated with Prudhoe Bay crude oil (116 and 1050 ppm). In the third experiment, sand lance avoided the oiled sand (131 and 1041 ppm) and buried in clean gravel, and also avoided both oiled sand (113 and 1004 ppm) and clean silt, and chose to remain in the water column. The sediment particle size and the way it affects water flow through the sediment seemed to be responsible for the preferences. We suggest that the sediment type, the sediment distribution, the nutritional state of the fish, and the predation pressure influence how sand lance use the sediment as a refuge and how they respond to contamination of that refuge.Contribution No. 1392 of the School of Oceanography, University of Washington     

Potential of Eucalyptus globulus for the phytoremediation of metals in a Moroccan iron mine soil—a case study

Environmental Science and Pollution Research - The contamination left by abandoned mines demands sustainable mitigation measures. Hence, the aim of this study was to examine the phytoremediator...     

Utilisation of mangroves and seagrasses by fishes in the Negombo Estuary,Sri Lanka

In two years of sampling, 10 287 fishes belonging to 62 species (39 families) were collected from mangroves and seagrasses of the Negombo Estuary. Of the species collected, 70% were marine, 27% estuarine and 3% freshwater. Aplocheilus melastigma, Ambassis dayi, Etroplus suratensis, E. maculatus, Bathygobius fuscus and Arothron immaculatus constituted 90% of the catch. Sixteen species were caught only from mangroves, 6 only from seagrasses, and 40 from both. The number of species, individuals, biomass and diversity were higher in seagrasses than in mangroves. Gobies and some siganids moved to the mangrove habitat as they grew, but cichlids, triacanthids, some eleotrids and tetraodontids preferred seagrasses. The number of species and individuals caught increased at the beginning of the north-east monsoon when the rainfall was low. The number of species and individual numbers were positively correlated with salinity and dissolved oxygen and negatively correlated with water temperature. Of the 33 species examined, seagrasses formed >25% of the gut content in juvenile Lates calcarifer, Apogon thermalis, E. suratensis, E. maculatus, Siganus javus, Butis butis and Bathygobius fuscus. Mangrove litter was the main gut content of the family Syngnathidae. E. suratensis, E. maculatus and S. javus from seagrasses contained more filamentous algae than seagrasses in their stomachs. S. javus collected from mangroves also contained more seagrasses in their stomachs than mangrove litter, indicating that the association of juvenile fishes with mangroves or seagrasses may not be obligate in estuaries subject to low tidal fluctuations.     

The assessment of water quality in the Lower Luján River (Buenos Aires,Argentina): phytoplankton and algal bioassays

The monitoring of river phytoplankton and several hydrological, physical and chemical variables, in combination with bioassays using Selenastrum capricornutum Printz, allowed the characterisation of three distinct reaches of the Lower River Luján. The upstream stretch, characterised by the lowest depth and discharge, registered the highest nutrient, dissolved heavy metal and chlorophyll a concentrations in accordance with low phytoplankton diversity and the occurrence of several species typical of organically polluted lowland rivers. A downstream improvement, concomitant to increasing river discharge, is revealed by a progressive decrease of organic pollution parameters even though algal toxicity is registered through bioassays. The water input from the Parana River through the G. Arias Channel plays an important role in the regulation of the limnology of the Lower Luján River. As a result of marked increasing discharge, depth and width, there is a decrease in nutrient concentration and phytoplankton density and an increase in dissolved oxygen concentration. Likewise, algal growth rates in the bioassays showed less toxic effect.     

Leaching and degradation of corn and soybean pesticides in an Oxisol of the Brazilian Cerrados

Pesticide pollution of ground and surface water is of growing concern in tropical countries. The objective of this pilot study was to evaluate the leaching potential of eight pesticides in a Brazilian Oxisol. In a field experiment near Cuiabá, Mato Grosso, atrazine, chlorpyrifos, lambda-cyhalothrin, endosulfane alpha, metolachlor, monocrotofos, simazine, and trifluraline were applied onto a Typic Haplustox. Dissipation in the topsoil, mobility within the soil profile and leaching of pesticides were studied for a period of 28 days after application. The dissipation half-life of pesticides in the topsoil ranged from 0.9 to 14 d for trifluraline and metolachlor, respectively. Dissipation curves were described by exponential functions for polar pesticides (atrazine, metolachlor, monocrotofos, simazine) and bi-exponential ones for apolar substances (chlorpyrifos, lambda-cyhalothrin, endosulfane alpha, trifluraline). Atrazine, simazine and metolachlor were moderately leached beyond 15 cm soil depth, whereas all other compounds remained within the top 15 cm of the soil. In lysimeter percolates (at 35 cm soil depth), 0.8-2.0% of the applied amounts of atrazine, simazine, and metolachlor were measured within 28 days after application. Of the other compounds less than 0.03% of the applied amounts was detected in the soil water percolates. The relative contamination potentials of pesticides, according to the lysimeter study, were ranked as follows: metolachlor > atrazine = simazine > monocrotofos > endsulfane alpha > chlorpyrifos > trifluraline > lambda-cyhalothrin. This order of the pesticides was also achieved by ranking them according to their effective sorption coefficient Ke, which is the ratio of Koc to field-dissipation half-life.