Removal and desorption of chromium in synthetic effluent by a mixed culture in a bioreactor with a magnetic field

Two chromium removal experiments were performed in bioreactors with and without a magnetic field under the same conditions.The release of the chromium present in the biomass was tested in two experiments one with the initial pH of the medium and one with pH 4.0.The objective was to remove Cr(Ⅵ) and total Cr from the effluent,this was carried out by placing biological treatments of synthetic effluent contaminated with 100 mg/L of Cr(Ⅵ) in a bioreactor with neodymium magnets that applied a magnetic field(intensity85.4 mT) to the mixed culture.The removal of Cr(Ⅵ) was approximately 100.0% for the bioreactor with a magnetic field and 93,3% for the bioreactor without a magnetic field for9 hr of recirculation of the synthetic effluent by the bioreactor.The removal of total Cr was61.6% and 48.4%,with and without a magnetic field,respectively;for 24 hr.The desorption of Cr(VI) in the synthetic effluent was 0.05 mg/L,which is below the limit established by Brazilian legislation(0.1 mg/L) for the discharge of effluent containing Cr(Ⅵ) into bodies of water.The results obtained for the removal of chromium in synthetic effluent suggested that there was no significant influence on the viable cell count of the mixed culture.The desorption of Cr(Ⅵ) in synthetic effluent after bioadsorption of chromium by the mixed culture in the process of removal of chromium in bioreactors with and without a magnetic field was not significant in either of the experiments with different initial pHs.     

Evaluation of inorganic pyrophosphate in amniotic fluid as a mode of prenatal diagnosis of osteogenesis imperfecta

Using a modified procedure by Solomons and Styner (1969), an evaluation of inorganic pyrophosphate (PPi) was performed on the amniotic fluid of two fetuses at risk for osteogenesis imperfecta (OI) at 14½ weeks gestation. The parents of both cases had a previous child with OI, Type II. The normal control group at 14–16 weeks gestation had PPi values ranging from 22.0–59.2 ug/100 ml, with a mean of 38.6±9.51 ug/100 ml. In each at-risk fetus, the amniotic fluid PPi value was within normal range. The first baby was born phenotypically normal at term. Intrauterine radiographic and fetal sonograms were done on the second fetus at approximately 19 weeks gestation. Both showed evidence of OI, Type II. The pregnancy was terminated at 21 weeks. Radiologic studies of the aborted fetus were consistent with OI, Type II. Our results indicate that the evaluation of PPi levels in amniotic fluid is not the method of choice for prenatal diagnosis of IO.     

DEVELOPMENT AND TESTING OF BIOINDICATORS FOR MONITORING THE CONDITION OF ESTUARINE ECOSYSTEMS

As part of the Environmental Monitoring and Assessment Programin 1991, the field efficacy of six research indicators wasexamined in the estuarine systems of the Gulf of Mexico. Theutility of these indicators was tested by examining thoseresponses at both ends of multiple environmental gradients;namely, under minimally impacted conditions (reference) andheavily impacted conditions (by hypoxia, industrialdischarges, agricultural runoff). In addition, the geographiceffects of location (east and west of the Mississippi River)were examined. Numbers and frequencies of pathologies,abundance of splenic macrophage aggregates, and vertebralabnormalities showed response patterns that suggest widerfield testing along full gradients rather than simply theextremes of the gradient are warranted. Selected bloodproteins showed some promise but logistical constraints inestuarine environments may limit its utility. Concentrationsof selected organic compounds in bile showed no differences inthis study between references and contaminated sites.Molecular bioindicators are discussed with regard to theirpotential utility as indicators of ecosystem conditions. Ofthese potential indicators, the use of vitellogenin assays asa measure of reproductive impairment and frequency of shelldisease in selected crustaceans as an indicator ofimmunological aberrations deserve further examination.     

Are anthropogenic factors affecting nesting habitat of sea turtles? The case of Kanzul beach,Riviera Maya-Tulum (Mexico)

Marine coast modification and human pressure affects many species, including sea turtles. In order to study nine anthropogenic impacts that might affect nesting selection of females, incubation and hatching survival of loggerhead (Caretta caretta) and green turtle (Chelonia mydas), building structures were identified along a 5.2 km beach in Kanzul (Mexico). A high number of hotels and houses (88; 818 rooms), with an average density of 16.6 buildings per kilometer were found. These buildings form a barrier which prevents reaching the beach from inland, resulting in habitat fragmentation. Main pressures were detected during nesting selection (14.19% of turtle nesting attempts interrupted), and low impact were found during incubation (0.77%) and hatching (4.7%). There were three impacts defined as high: beach furniture that blocks out the movement of hatchlings or females, direct pressure by tourists, and artificial beachfront lighting that can potentially mislead hatchlings or females. High impacted areas showed lowest values in nesting selection and hatching success. Based on our results, we suggest management strategies to need to be implemented to reduce human pressure and to avoid nesting habitat loss of loggerhead and green turtle in Kanzul, Mexico.     

Methane generation in tropical landfills: simplified methods and field results

This paper deals with the use of simplified methods to predict methane generation in tropical landfills. Methane recovery data obtained on site as part of a research program being carried out at the Metropolitan Landfill, Salvador, Brazil, is analyzed and used to obtain field methane generation over time. Laboratory data from MSW samples of different ages are presented and discussed; and simplified procedures to estimate the methane generation potential, Lo, and the constant related to the biodegradation rate, k are applied. The first order decay method is used to fit field and laboratory results. It is demonstrated that despite the assumptions and the simplicity of the adopted laboratory procedures, the values Lo and k obtained are very close to those measured in the field, thus making this kind of analysis very attractive for first approach purposes.     

Colonized beads as inoculum for marine biodegradability assessment: Application to Linear Alkylbenzene Sulfonate

An innovative biodegradation test system was developed in order to fill the current gap for cost effective and environmentally relevant tools to assess marine biodegradability. Glass beads were colonized by a biofilm in an open flow-through system of seawater with continuous pre-exposure to Linear Alkylbenzene Sulfonate (LAS) (20 μg/L). Thereafter, such colonized beads were added as inoculum in different test systems. [¹⁴C]-LAS (5–100 μg/L) was added and primary and ultimate biodegradation were assessed. The bacterial density collected on the beads (10⁹ bact./mL beads) was ca. 3 orders of magnitude higher than the typical seawater content. The LAS mineralization lag phase duration decreased from 55 to < 1 days and the mineralization extent increased from 53 to 90% as the colonized beads volume increased from 10 to 275 mL. This is the first demonstration of marine bacteria's ability to mineralize LAS. On the opposite, less than 13% LAS was mineralized in seawater only. The colonized beads possibly enhanced the probability to encounter the full degraders' consortium in a low volume of seawater (100 mL).     

Ecotourism as a development strategy: experiences from Costa Rica

This article reflects on the Costa Rican experiences with ecotourism by assessing the positive and negative environmental, economic and social impacts of ecotourism development at four tourist destinations—Manuel Antonio, Monteverde, Tortuguero and ASCOMAFOR. These destinations represent different stages of tourism development. The assessment shows that the development of ecotourism has a dilemma character. Compared to alternative land-use options, ecotourism remains a promising development strategy. However, it should be embedded in a broader process of capacity building.     

Potential physiological effects of pharmaceutical compounds in Atlantic salmon (<Emphasis Type="Italic">Salmo salar</Emphasis>) implied by transcriptomic analysis

Background, aim, and scope  

Pharmaceuticals are emerging pollutants widely used in everyday urban activities which can be detected in surface, ground, and drinking waters. Their presence is derived from consumption of medicines, disposal of expired medications, release of treated and untreated urban effluents, and from the pharmaceutical industry. Their growing use has become an alarming environmental problem which potentially will become dangerous in the future. However, there is still a lack of knowledge about long-term effects in non-target organisms as well as for human health. Toxicity testing has indicated a relatively low acute toxicity to fish species, but no information is available on possible sublethal effects. This study provides data on the physiological pathways involved in the exposure of Atlantic salmon as representative test species to three pharmaceutical compounds found in ground, surface, and drinking waters based on the evaluation of the xenobiotic-induced impairment resulting in the activation and silencing of specific genes.     

Territorial User Rights for Fisheries as Ancillary Instruments for Marine Coastal Conservation in Chile

Territorial user rights for fisheries have been advocated as a way to achieve sustainable resource management. However, few researchers have empirically assessed their potential as ancillary marine conservation instruments by comparing them to no‐take marine protected areas. In kelp (Lessonia trabeculata) forests of central Chile, we compared species richness, density, and biomass of macroinvertebrates and reef fishes among territorial‐user‐right areas with low‐level and high‐level enforcement, no‐take marine protected areas, and open‐access areas in 42 100‐m subtidal transects. We also assessed structural complexity of the kelp forest and substratum composition. Multivariate randomized permutation tests indicated macroinvertebrate and reef fish communities associated with the different access regimes differed significantly. Substratum composition and structural complexity of kelp forest did not differ among access regimes. Univariate analyses showed species richness, biomass, and density of macroinvertebrates and reef fishes were greater in highly enforced territorial‐user‐right areas and no‐take marine protected areas than in open‐access areas. Densities of macroinvertebrates and reef fishes of economic importance were not significantly different between highly enforced territorial‐user‐right and no‐take marine protected areas. Densities of economically important macroinvertebrates in areas with low‐level enforcement were significantly lower than those in areas with high‐level enforcement and no‐take marine protected areas but were significantly higher than in areas with open access. Territorial‐user‐right areas could be important ancillary conservation instruments if they are well enforced. Derechos de Usuario Territoriales para Pesquerías como Instrumentos Accesorios para la Conservación Marina Costera en Chile