Factors affecting RPSI in imposex monitoring studies using Nucella lapillus (L.) as bioindicator

Nucella lapillus (L.) is a marine gastropod mollusc widely used as a bioindicator of TBT pollution in the North Atlantic coastlines. The species reproductive cycle and the male penis length seasonal/spatial variation were studied at a single site at Aveiro seashore (NW Portugal) between December 2005 and June 2007. The main objective of this work is to assess if the "Relative Penis Size Index" (RPSI)--an important imposex assessment index--varies seasonally and spatially in the same sampling site and how this can affect results obtained in imposex monitoring programmes. Animals able to reproduce were found every month but a seasonal pattern in N. lapillus reproductive cycle was evident. Female gametogenic maturation varied seasonally and a decrease in capsule gland volume and condition factor occurred in late summer/early autumn. The gametogenesis in males did not show a significant seasonal variation as in females but the condition factor, penis length, amount of sperm and prostate volume also diminished in late summer/early autumn. On the other hand, males that were close to egg capsules clusters had larger penises than those far away from clusters. The temporal and spatial male penis length variation introduces a bias on imposex assessment results when using RPSI and the magnitude of the error involved is evaluated for different TBT pollution levels scenarios. We consider that RPSI provides interesting and complementary information that should not be excluded from monitoring programmes, but temporal or spatial comparisons of imposex should be based on other more reliable imposex indices like the VDSI.     

Mercury pollution in Ria de Aveiro (Portugal): a review of the system assessment

The Ria de Aveiro (Portugal) is a coast al lagoon adjacent to the Atlantic Ocean and it has an inner bay (Laranjo bay) that received a highly contaminated effluent discharged by a mercury cell chlor-alkali plant from the 1950s until 1994. The aim of this study is to review in a holistic way several research studies that have been carried out in the Ria de Aveiro, in order to evaluate the remobilization of the mercury accumulated within the system and the recovery of the lagoon. The spatial distribution of the total mercury in the surrounding terrestrial environment has also been considered. Results indicate that the main mercury contamination problems in the Ria de Aveiro are confined to the Laranjo bay. Mercury export to the coastal waters and its impact on the nearshore compartments (water column, sediment and biota) are low. No direct effects of the mercury from nearby industrial activities were detected in Aveiro's urban soils, although historical mercury contamination is still affecting soil quality in the immediate vicinity of the chlor-alkali plant, located in Estarreja. Moreover, macrophyte harvesting for human direct or indirect use and the consumption of mussels, crabs and the sea bass from the Laranjo bay may constitute a health risk. Further studies focusing on developing skills for the restoration of the ecosystem are presently underway.     

Geological Characterization and Environmental Implications of the Placement of the Morelia Dump,Michoacán,Central Mexico

Abstract

The landfill of Morelia, the capital city of the state of Michoacán in central-western Mexico, is located 12 km west of the city and has operated since 1997 without a structure engineered and designed to control the generation in situ of biogas and leachates. A geological evaluation of the landfill site is presented in this paper. The results indicate that the site lacks ideal impermeable sub-surface strata. The subsurface strata consist of highly fractured basaltic lava flows (east-west fault and fracture system trend) and sand-size cineritic material with high permeability and porosity. Geochemical analysis of groundwater from Morelia’s municipal aquifer shows a high concentration of heavy metals (Cd, Pb, As) exceeding the Mexican environmental regulations, along with the presence of some organic pollutants (phenols). Analyses of samples of the landfill’s permanent leachate ponds show very high concentrations of the same contaminants. Samples were taken from the leachate pond and from nearby water-wells during the rainy season (summer 1997) and the dry season (spring 1997, 1998, and 1999). In all cases, the concentration of contaminants registered exceeded the standards for drinking water of the World Health Organization (American Public Health Association, American Water Works Association, and Water Pollution Control Federation, 2000). Some metal contaminants could be leaching directly from the landfill.     

Bisphenol A migration from plastic materials: direct insight of ecotoxicity in Daphnia magna

Bisphenol A (BPA) is an endocrine disrupting chemical (EDC) whose migration from food packaging is recognized worldwide. However, the real overall food contamination and related consequences are yet largely unknown. Among humans, children’s exposure to BPA has been emphasized because of the immaturity of their biological systems. The main aim of this study was to assess the reproductive impact of BPA leached from commercially available plastic containers used or related to child nutrition, performing ecotoxicological tests using the biomonitoring species Daphnia magna. Acute and chronic tests, as well as single and multigenerational tests were done. Migration of BPA from several baby bottles and other plastic containers evaluated by GC-MS indicated that a broader range of foodstuff may be contaminated when packed in plastics. Ecotoxicological test results performed using defined concentrations of BPA were in agreement with literature, although a precocious maturity of daphnids was detected at 3.0 mg/L. Curiously, an increased reproductive output (neonates per female) was observed when daphnids were bred in the polycarbonate (PC) containers (145.1?±?4.3 % to 264.7?±?3.8 %), both in single as in multigenerational tests, in comparison with the negative control group (100.3?±?1.6 %). A strong correlated dose-dependent ecotoxicological effect was observed, providing evidence that BPA leached from plastic food packaging materials act as functional estrogen in vivo at very low concentrations. In contrast, neonate production by daphnids cultured in polypropylene and non-PC bottles was slightly but not significantly enhanced (92.5?±?2.0 % to 118.8?±?1.8 %). Multigenerational tests also revealed magnification of the adverse effects, not only on fecundity but also on mortality, which represents a worrying trend for organisms that are chronically exposed to xenoestrogens for many generations. Two plausible explanations for the observed results could be given: a non-monotonic dose–response relationship or a mixture toxicity effect.     

Municipal solid waste shear strength parameters defined through laboratorial and in situ tests

This paper presents the parameters of municipal solid waste shear strength determined in the laboratory (triaxial tests) and by in situ tests: standard penetration tests (SPT) and cone penetration tests (CPT). The results analyzed here are part of a study carried out on the Santo Tirso landfill (north of Portugal) between 2001 and 2007. The influence of the strain levels, waste composition, and waste age on the shear strength parameters is presented, as well as an attempt to establish some correlations between the SPT and CPT tests and to estimate municipal solid waste (MSW) friction angles from the SPT tests. The results indicate that the aging of the waste, which is characterized by a decrease in fibrous and organic materials and an increase in inert materials and fine fraction, leads to an increase in frictional resistance and to a decrease in cohesion. The results of the SPT and CPT tests indicate higher penetration resistance in older and deeper waste. Estimating the frictional resistance from the SPT test seems to obey an empirical relationship expressed by a power function, which depends on the strain level.

Implications: Comparison of shear strength parameters of municipal solid waste (MSW) determined through laboratory (triaxial tests) and in situ tests (SPT and CPT) showed that the greater amount of fibrous and granular elements leads to an increase in “cohesion” and in friction angle values, respectively. Waste aging results in an increase in frictional resistance and in a decrease in “cohesive” resistance. This is consistent with the composition changes with aging: increase of the relative quantity of inert materials and fine fraction, and decrease in particle size, in organic matter content, and in fabrics and plastics.     

Kinetic Behavior in Melt State and Solid State Polymerization of Lactide Using Magnesium Stearate as Catalyst

Solid state polymerizations (SSP) and the kinetic behavior in melt state of l-lactide polymerizations employing magnesium stearate as catalyst were investigated. The solid state polymerizations were carried out in two steps where pre-polymers were first prepared in melt polymerizations at 180 °C and the subsequent post-polymerizations were performed around the Tc of polylactide (PLA). In order to find the initial SSP conditions, kinetic profiles of melt polymerizations of l-lactide with magnesium stearate were determined. According to the kinetics data the melt polymerizations were found to be first order with respect to lactide as evident from a linear relationship of logarithmic variations of l-lactide concentration versus time using catalyst/monomer ratios of 1:500 and 1:5,000. When the catalyst content is increased to 1:100 the relationship loses its linearity due to fast propagation in the early stages of the reaction. From the GPC data it can be noted that the molecular weight of PLA can be increased by 5–17 times under the conditions established for our SSP experiments. A comparison between the two step solid state polymerizations and already reported melt polymerizations using the same catalyst showed that SSP furnished polymers with much lower amount of polymer degradation.     

Experimental study on the survival of the water hyacinth (Eichhornia crassipes (Mart.) Solms—Pontederiaceae) under different oil doses and times of exposure

In the last decades, petroleum activities have increased in the Brazilian Amazon where there is oil exploration on the Urucu River, a tributary of the Amazon River, about 600 km from the city of Manaus. Particularly, transportation via the Amazon River to reach the oil refinery in Manaus may compromise the integrity of the large floodplains that flank hundreds of kilometers of this major river. In the Amazon floodplains, plant growth and nutrient cycling are related to the flood pulse. When oil spills occur, floating oil on the water surface is dispersed through wind and wave action in the littoral region, thus affecting the vegetation of terrestrial and aquatic environments. If pollutants enter the system, they are absorbed by plants and distributed in the food chain via plant consumption, mortality, and decomposition. The effect of oil on the growth and survival of vegetation in these environments is virtually unknown. The water hyacinth [Eichhornia crassipes (Mart.) Solms] has a pantropical distribution but is native to the Amazon, often growing in high-density populations in the floodplains where it plays an important role as shelter and food source for aquatic and terrestrial biota. The species is well known for its high capacity to absorb and tolerate high levels of heavy metal ions. To study the survival and response of water hyacinth under six different oil doses, ranging from 0 to 150 ml l^?1, and five exposure times (1, 5, 10, 15, and 20 days), young individuals distributed in a completely randomized design experiment composed of vessels with a single individual each were followed over a 50-day period (30-day acclimatization, 20 days under oil treatments). Growth parameters, biomass, visual changes in the plants, and pH were recorded at 1, 5, 10, 15, and 20 days. Increasing the time of oil exposure caused a decrease in biomass, ratio of live/dead biomass and length of leaves, and an increase in the number of dead leaves. Dose of oil and time of exposure are the most important factors controlling the effects of petroleum hydrocarbons on E. crassipes. Although the species is able to survive exposure to a moderate dose of oil, below 75 ml l^?1 for only 5 days, severe alterations in plant growth and high mortality were observed. Therefore, we conclude that Urucu oil heavily affects E. crassipes despite its known resistance to many pollutants.     

Potential re-colonisation by cladocerans of an acidic tropical pond

To predict how re-colonisation of acidified lakes will proceed, at least two approaches are possible: (i) to compare the life history traits of candidate species and determine which one has the highest fitness, and (ii) to simulate a more realistic scenario carrying out experiments with the grouping of the candidate species, so that the intrinsic rate of natural increase of each species is integrated with its sensitivity to low pH and its ability to compete with the other candidate populations. The objective of the present study was to investigate the future re-colonisation of such acidified systems, taking as case-study a tropical pond (Lagoa das Dunas, Camaçari, BA, Brazil) and four species of cladocerans occurring in nearby water bodies (Ceriodaphniacornuta, Ceriodaphniasilvestrii, Latonopsisaustralis and Macrothrix elegans), by comparing the two above mentioned approaches. The second approach included two sets of in situ microcosms experiments, one simulating the re-colonisation by immigrating ephippia, thus using neonates of each species as colonisers, and another simulating the immigration of adults. Both these simulations followed nearly the same trends. The integration of the effects of a higher temperature, a different photoperiod and species competition determined differences in the species densities ranking between the two approaches: life history versus microcosms. The densities of C.cornuta in the microcosms matched the biphasic concentration/response hormetic model, in the simultaneous presence of two increasingly intense stressors (interspecific competition and acidity), with a low-dose stimulation and a high-dose inhibition. The present study provided, thus, a further support to the acceptance of hormesis in ecotoxicology, also at the population level in multispecies experiments.     

Stabilization/solidification of fly ashes and concrete production from bottom and circulating ashes produced in a power plant working under mono and co-combustion conditions

Two combustion tests were performed in a fluidized bed combustor of a thermo-electric power plant: (1) combustion of coal; (2) co-combustion of coal (68.7% w/w), sewage sludge (9.2% w/w) and meat and bone meal (MBM) (22.1% w/w). Three samples of ashes (bottom, circulating and fly ashes) were collected in each combustion test. The ashes were submitted to the following assays: (a) evaluation of the leaching behaviour; (b) stabilization/solidification of fly ashes and evaluation of the leaching behaviour of the stabilized/solidified (s/s) materials; (c) production of concrete from bottom and circulating ashes. The eluates of all materials were submitted to chemical and ecotoxicological characterizations. The crude ashes have shown similar chemical and ecotoxicological properties. The s/s materials have presented compressive strengths between 25 and 40 MPa, low emission levels of metals through leaching and were classified as non-hazardous materials. The formulations of concrete have presented compressive strengths between 12 and 24 MPa. According to the Dutch Building Materials Decree, some concrete formulations can be used in both scenarios of limited moistening and without insulation, and with permanent moistening and with insulation.