Distribution and possible source of trace elements in the sediment cores of a tropical macrotidal estuary and their ecotoxicological significance

The paper presents the first document regarding concentration, distribution and possible sources of selected trace elements (Cu, Fe, Mn, Zn, Cr, Co, Ni, Pb, Al, B and Ba) in core sediments (<63 micro particle size) from the lower stretch of Hugli (Ganges) estuary, northeast coast of Bay of Bengal by ICP-AES and EDXRF to evaluate geochemical processes influencing their distribution and possible environmental consequences. The levels of elements showed a wide range of variations in different core depths, in upper and lower intertidal zones as well as among three sampling stations. The most interesting feature of the study is the downward increase of concentrations of majority of the elements reaching overall maximum values at a depth of 20-28 cm in upper littoral zone of the site located in the extreme downstream stretch of the estuary. Values of organic carbon showed very strong positive correlations with most of the elements as revealed by correlation matrix (r) values. The interelemental relationship revealed the identical behavior of element during its transport in the estuarine environment. The overall variation in concentration can be attributed to differential discharge of untreated effluents originating from industrial, agricultural, and aquacultural sources as well as from domestic sewage along with the fishing and boating activities. The resulting compositional dataset was tested by principal component analyses and cluster analyses. Pollution load index (PLI) and index of Geoaccumulation (Igeo) revealed overall low values but the enrichment factors (EFs) for Pb were typically high for all the stations. The mean concentrations of Zn and to some extent Cu exceeded the Effects Range-Low (ER-L) values in the majority of the cases indicating that there may be some ecotoxicological risk to organisms living in sediments. The concentration of the trace elements reported in this work is useful as baselines for comparison in future sediment quality studies.     

Wastewater reuse: modeling chloroform formation

The chloroform is a substance that presents a significant risk to or via the aquatic environment. Thus, the emissions, discharges and losses of this substance need to be controlled during wastewater disinfection for reclamation and reuse purposes. Due to its carcinogenetic potential, multiple studies have been carried out on drinking and surface/natural waters but less consideration has been directed to the wastewater disinfection. The focus of this work studied the formation of chloroform during chlorination in prepared waters or artificial matrices that intended to simulate wastewaters stored in landscape ponds for green areas irrigation. The relation between reaction time, chlorine dose, and chloroform formation and the variation of the dissolved organic carbon (DOC) content during the reaction was assessed. A two-variant model was proposed to simulate breakpoint chlorination practices (when chlorine dose is equal or lower than chlorine demand) and super chlorination techniques (when chlorine dose tends to surpass chlorine demand). The model was validated by the application of actual data from working conditions of six wastewater treatment plants located in Algarve, Portugal, including other data obtained in previous research studies that were not used in the model development, and by comparing the predicted values with real measured ones.     

The effect of aged litter materials on polyatomic ion concentrations in fractionated suspended particulate matter from a broiler house

Inorganic emissions from livestock production and subsequent deposition of these ions can be a major source of pollution, causing nitrogen enrichment, eutrophication, acidification of soils and surface waters, and aerosol formation. In the poultry house, ammonia and hydrogen sulfide emissions can also adversely affect the health, performance, and welfare of both animals and human operators. The persistence and long life expectancy of ammonia, odors and toxic pollutants from poultry houses may be due to the ability of suspended particulate matter (SPM) to serve as carriers for odorous compounds such as ammonium ions and other inorganic compounds (e.g., phosphate, sulfate, nitrate, etc.). SPM is generated from the feed, animal manure, and the birds themselves. A large portion of odor associated with exhaust air from poultry houses is SPM that has absorbed odors from within the houses. Understanding the fate and transport processes of ammonia and other inorganic emissions in poultry houses is a necessary first step in utilizing the appropriate abatement strategies. In this study, the examination and characterization of ammonium ions, major components of odors and toxic gases from poultry operations, and other ions in suspended particulate matter in a broiler house were carried out using particle trap impactors. The SPM from the particle trap impactors was extracted and analyzed for its ionic species using ion chromatography (IC). The results showed concentrations of polyatomic ions in suspended particulate matter were found to increase with successive flocks and were highly concentrated in the larger size particulate matter. In addition, the ions concentrations appeared to reach a maximum at the middle of flock age (around the fourth week), tapering off toward the end in a given flock (possibly due to ventilation rates to cool off larger birds). Thus, it can be inferred that aged of bedding materials affects the ionic concentrations in aerosol particulate matter more than the age of the birds.

Implications: In the poultry house, toxic gas emissions can adversely affect the health, performance, and welfare of both animals and human operators. The persistence of these toxic pollutants from poultry houses may be due to the ability of suspended particulate matter (SPM) to serve as carriers for these compounds (inorganic ions). Our study showed that polyatomic ions in suspended particulate matter were found to increase with successive flocks and were highly concentrated in the larger size SPM. Understanding the effect of management practices on poultry air emissions will lead to innovative best management practices to safeguard the health and welfare of the animals as well as those of the poultry operators, along with reducing the impact of potential air pollution on the environment.     

Conservation of animals traded for medicinal purposes in Brazil: Can products derived from plants or domestic animals replace products of wild animals?

Regional Environmental Change - The use and trade of animals in traditional medicine involves many different species, some of which are threatened with extinction. Thus, evaluating biological and...     

Evaluation of the aggressive potential of marine chloride and sulfate salts on mortars applied as renders in the Metropolitan Region of Salvador--Bahia, Brazil

In recent years, growing interest has focused on determining the performance of materials and evaluating the service life of structures exposed to various environmental forces. In this context, the determination of the aggressive potential of marine salts on mortars used as external renders is critical. The present study aimed to evaluate the spatial distribution of marine salts relative to distance from the sea. This was done by monitoring the deposition rate of chlorides and sulfates in wet candle sensors, located at nine stations scattered around the Metropolitan Region of Salvador, state of Bahia, Brazil. The study also determined the effectiveness of water-soluble salts at penetrating three different types of mortars of varying cement content via deposition and diffusion. The methodology employed enabled an evaluation of the efficiency of the monitoring sensors' measurement of the aggressiveness potential of local marine aerosol, and determination of the comparative performance of the three mortars tested, from the standpoint of resistance to salt penetration. The type and amount of salts captured both in solution and in powder samples extracted from the mortars were determined by ion chromatography. The analysis of the various types of mortars tested indicated which types are more resistant to the aggressive potential of the region's marine aerosol and the distance from the shore where local buildings are liable to be most strongly affected.     

The reliability of experts' opinions in constructing a composite environmental index: The case of ESI 2005

The complexity of the environment demands a well-constructed composite environmental index (CEI) to provide a useful tool to draw attention to environmental conditions and trends for policy purposes. Among the common difficulties in constructing a proper CEI are uncertainties due to the selection of the most representative underlying variables or indicators. A degree of uncertainty accompanies experts' judgments, and to deal with vague, subjective or inconsistent information, logic other than classic is required. This study analyzes a procedure that uses different experts' opinions in constructing a CEI, with the use of paraconsistent annotated logic. For this, a sensitivity analysis of the Environmental Sustainability Index (ESI 2005) was used as an example to assess the reliability of experts' opinions. The uncertainty due to the disagreement in experts' opinions clearly indicates that the forms we presently use to measure and monitor the actual environment are insufficient, that is, there is a lack of a “science of sustainability”.     

Use and knowledge of fuelwood in three rural caatinga (dryland) communities in NE Brazil

The woody species known, used, and preferred as fuelwood were examined in three rural communities within the county of Soledade, Paraíba State, NE Brazil. Ethnobotanical information was collected using semi-structured interviews with more than 90% of the local households (55 adult residents; 31 women, and 24 males). The interviewees cited 36 plant species as fuelwoods, distributed among 30 genera and 15 families, in addition to two unidentified plants. The plant families represented by the largest numbers of species were Euphorbiaceae, Anacardiaceae, Mimosaceae, Caesalpiniaceae, Sapotaceae, and Fabaceae. The species Caesalpinia pyramidalis Tul. (“catingueira”) was cited with the greatest frequency in all three communities. Within the communities we found significant differences on the number of plants cited and actually used (p < 0.05), indicating that the residents knew more fuelwood species than they effectively harvest. The different distances from the communities to the urban centers were not related to differences on the use or the size of the stocks of fuelwood. Additionally, the study revealed that the communities examined still maintain a significant knowledge of the use of energy-providing plants in spite of the widespread use of liquefied petroleum gas (LPG). Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Collective work and resilience of complex systems

This article aims to describe the characteristics of collective working situations in complex systems – especially those in nuclear power plants – related to common forms of cooperation, in order to improve systems resilience. In addition, we will try to detail some aspects of collective working situations, emphasizing the differences between various forms of control. The similarities between work activities (multi-addressed messages, linkage to regulation, central and peripheral information) are nonetheless exposed. We conclude by proposing a contribution to support systems design, thus facilitating cooperation in teamwork activities.     

Urban daytime traffic noise prediction models

An evaluation was made of the acoustic environment generated by an urban highway using in situ measurements. Based on the data collected, a mathematical model was designed for the main sound levels (L _eq, L ₁₀, L ₅₀, and L ₉₀) as a function of the correlation between sound levels and between the equivalent sound pressure level and traffic variables. Four valid groups of mathematical models were generated to calculate daytime sound levels, which were statistically validated. It was found that the new models can be considered as accurate as other models presented in the literature to assess and predict daytime traffic noise, and that they stand out and differ from the existing models described in the literature thanks to two characteristics, namely, their linearity and the application of class intervals.     

In situ assays with tropical cladocerans to evaluate edge-of-field pesticide runoff toxicity

Tropical regions’ economy is usually based on agriculture, which involves an intensive use, and even frequent overuse, of pesticides. Nevertheless, not much research has been done on the impact of pesticides on tropical aquatic ecosystems, which are often contaminated by runoff-related pesticide inputs due to unpredictable and torrential rainfalls. This study aimed to: (i) adapt and evaluate a short-term sublethal in situ assay using post-exposure feeding as an endpoint, to the tropical cladoceran species Diaphanosoma brachyurum (collected at the Pedra do Cavalo dam in the Paraguaçu River basin, Bahia, Brazil), and, (ii) assess the role of the standard species Daphnia magna as an adequate laboratory surrogate. Lethal and sublethal (post-exposure feeding) responses were assessed for the two species. To evaluate these responses under environmentally realistic exposure conditions, a runoff event was simulated in an agricultural area previously contaminated with different deltamethrin concentrations. The resultant runoff water was used to set up microcosms with different dilutions, simulating the entrance of runoff water in an adjacent lentic system. An in situ assay with D. brachyurum was performed inside the microcosms, allowing to discriminate the effects due to deltamethrin from those due to other potential stressors associated with the experimental design (e.g. organism handling, load of suspended particles, microcosm design). Water samples were collected from microcosms to conduct a laboratory assay with D. magna. The in situ methodologies revealed to be suitable to conduct assays with D. brachyurum under tropical conditions, since all exposed organisms were successfully retrieved from the chambers. Furthermore, none of the potential stressors associated with the experimental design influenced the daphnids’ performance. The tropical cladoceran species, exposed under more realistic conditions, revealed to be more sensitive than the laboratory standard species: lethal effects were only observed for D. brachyurum and sublethal effects were noticed at a lower deltamethrin concentration for this species than for D. magna.