Storm-induced transfer of particulate trace metals to the deep-sea in the Gulf of Lion (NW Mediterranean Sea)

In order to calculate budgets of particulate matter and sediment-bound contaminants leaving the continental shelf of the Gulf of Lion (GoL), settling particles were collected in March 2011 during a major storm, using sediment traps. The collecting devices were deployed in the Cap de Creus submarine canyon, which represents the main export route. Particulate matter samples were analyzed to obtain mass fluxes and contents in organic carbon, Al, Cr, Co, Ni, Cu, Zn, Cd, Pb and La, Nd and Sm. The natural or anthropogenic origin of trace metals was assessed using enrichment factors (EFs). Results are that Zn, Cu and Pb appeared to be of anthropogenic origin, whereas Ni, Co and Cr appeared to be strictly natural. The anthropogenic contribution of all elements (except Cd) was refined by acid-leaching (HCl 1 N) techniques, confirming that Zn, Cu and Pb are the elements that are the most enriched. However, although those elements are highly labile (59–77 %), they do not reflect severe enrichment (EFs <4). Most particles originate from the Rhone River. This has been confirmed by two different tracing procedures using rare earth elements ratios and concentrations of acid-leaching residual trace metals. Our results hence indicate that even in this western extremity of the GoL, storm events mainly export Rhone-derived particles via the Cap de Creus submarine canyons to the deep-sea environments. This export of material is significant as it represents about a third of the annual PTM input from the Rhone River.     

Growth in urban extent and allometric analysis of West African cities

Urban area expansion is happening at much faster rates in Asian and African cities than elsewhere in the world. This study uses multi-temporal Landsat images to map the urban extent of six small to large cities in West Africa at four different time steps from the early 1970s–2010. The selected cities are Kumasi of Ghana, Daloa of Cote d’Ivoire, Abuja and Kano in Nigeria, Kindia of Guinea, and Ouagadougou of Burkina Faso. All cities revealed significant urban growth in both urban area and population; however, it was apparent that there was a lot of variability in urban area development. Exponential urban growth rates in the cities were measured as ranging between 0.026 and 0.077, with allometric scaling factors matching those of other countries.     

Trace elements in muscle of three fish species from Todos os Santos Bay,Bahia State,Brazil

In this study, an analysis was performed on the concentrations of the trace elements Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn in muscle of two carnivorous and one planktivorous fish species collected at Todos os Santos Bay (BTS). The accumulation order of the trace elements in Lutjanus analis was Al >Zn >Fe >Cr >Ba >Ni. In Cetengraulis edentulus, the order was Al >Fe >Zn >Cr >Ni >Mn >As. In the species Diapterus rhombeus, the order was Al >Fe >Zn >Cr >Ni >Mn >Cd. To determine the risk related to the consumption of fish, toxicity guidelines were used as standard references. It was observed that the species C. edentulus contained concentrations of As exceeding WHO limits, but these concentrations were acceptable according to the Agência Nacional de Vigilância Sanitária (ANVISA) guidelines. Cd levels were found only in D. rhombeus and in low concentrations according to the determinations of WHO and ANVISA. Pb levels were not detected in any of the three fish species. The analyzed elements did not differ statistically according to the species and feeding habits. The results point to possible risks of human contamination by As related to the consumption of the fish species C. edentulus from the BTS.     

Collaborative study to improve the quality control of rare earth element determinations in environmental matrices

In order to control the quality of rare earth determinations in environmental matrices, the Standards, Measurements and Testing Programme (formerly Community Bureau of Reference, BCR) of the European Commission has started a project, the final aim of which is to certify four types of matrices (tuna muscle, mussel tissue, aquatic plant and estuarine sediment) for their contents of a range of rare earth elements (Sc, Y and the lanthanides: La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu). The elements U and Th were added to the study. The first part of this project consisted of an interlaboratory study which aimed to test the feasibility of preparation of environmental reference materials and to detect and remove most of the pitfalls observed in rare earth determinations. This paper presents the preparation of the four matrices for the intercomparison study and for the candidate reference material. The main results are presented of the interlaboratory study that was carried out prior to the certification campaign. This collaborative trial is the first attempt ever carried out at this scale to evaluate the state-of-the-art of rare earth determinations in the environment. Its impact on the improvement of chemical measurements will have positive effects on the comparability of data necessary for environmental monitoring.     

Vegetation as an indicator of environmental changes

Composition of the vegetation and the properties of its environment are related, as was shown by research. In these, mostly statistical-correlative studies, both the vegetation and some growth factors, such as plant nutrients and moisture supply were analyzed and studied on interdependence. At present the environmental conditions can be estimated in the field from the floristic composition with regard to differences both in the combination of plant species and in their relative biomass production. With a vegetation survey the spatial pattern of the different environmental conditions can be indicated. For instance, the places where moisture supply gradients occur can be detected, also a better understanding is obtained of the environmental equalization and the decreasing number of plant species and spatial diversity. Conclusions can be drawn about changes in the vegetation to be expected, from the combined occurrence of, a terrestrial vegetation indicating an eutrofied environment and a water vegetation indicating a relatively oligotrophic environment. By comparing vegetation recordings of the past and present, environmental changes that have occurred in the same place can be indicated. By vegetations situated in different places in relation with soil profile properties the consequences of environmental changes can be predicted. For instance, lowering of the ground water table and intensifying the agricultural use. On the other hand, measures can be suggested to increase the biological value of land and water, for instance, indication of seepage areas and floristically rich areas in the field.     

Nutrient baselines of Cerrado low-order streams: comparing natural and impacted sites in Central Brazil

The aquatic systems responsible for water supply in the Brazilian Federal District (FD) have been threatened by anthropogenic pressures, especially considering the expressive demographic increase in the region during the last decades. The purposes of this research were: (a) to assess the water quality in streams located in the FD by monitoring physical–chemical variables; (b) to define baselines for these variables among different ecological status categories. The 14 investigated streams were sampled between 2006 and 2009, in the dry (August–September, 2006, 2008, 2009) and rainy (March–April, 2008, 2009) seasons. All sampling sites were classified in four categories (“very impacted”, “impacted”, “in transition” and “natural”) using an adaptation of a rapid habitat assessment protocol. Differences in water quality among sites were generally well predicted in the four ecological status categories defined by the protocol, which showed a gradient in nutrient concentrations from reference sites classified as “natural” (medians: electrical conductivity?=?7.3 μS cm^?1; nitrate?=?0.040 mg L^?1; ammonium?=?0.039 mg L^?1; soluble reactive phosphorus (SRP)?=?<0.001 mg L^?1; total phosphorus (TP)?=?0.006 mg L^?1; ) to those classified as “very impacted” (medians: electrical conductivity?=?87.7 μS cm^?1; nitrate?=?0.247 mg L^?1; ammonium?=?0.219 mg L^?1; SRP?=?0.010 mg L^?1; TP?=?0.035 mg L^?1). Point sources inputs were the main factor for water quality deterioration. The nutrient baselines reported were relatively low when compared to data collected from reference areas in Brazil (e.g., São Paulo State) or temperate regions, especially for TP.     

Cumulative influences of a small city and former mining activities on the sediment quality of a subtropical estuarine protected area

This study aimed to evaluate the sediment quality in the estuarine protected area known as Cananéia-Iguape-Peruíbe (CIP-PA), located on the southeastern coast of Brazil. The study was designed considering possible negative effects induced by the city of Cananéia on the sediment quality of surrounding areas. This evaluation was performed using chemical and ecotoxicological analyses. Sediments were predominantly sandy, with low CaCO₃ contents. Amounts of organic matter varied, but higher contents occurred closer to the city, as well as did Fe and Total Recoverable Oils and Greases (TROGs) concentrations. Contamination by Cd and Cu was revealed in some samples, while concentrations of Zn were considered low. Chronic toxicity was detected in all tested sediments and acute toxicity occurred only in sediments collected near the city. The principal component analysis (PCA) revealed an association among Cd, Cu, Fe, TROG, fines, organic matter, CaCO₃, and chronic toxicity, whereas acute toxicity was found to be associated with Zn and mud. However, because Zn levels were low, acute toxicity was likely due to a contaminant that was not measured. Results show that there is a broad area within the CIP-PA that is under the influence of mining activities (chronic toxicity, moderate contamination by metals), whereas poorer conditions occur closer to Cananéia (acute toxicity); thus, the urban area seems to constitute a relevant source of contaminants for the estuarine complex. These results show that contamination is already capable of producing risks for the local aquatic biota, which suggests that the CIP-PA effectiveness in protecting estuarine biota may be threatened.     

FIA-coupled spectrophotometric method for determination of Cr (VI) traces in natural waters: application of in-line dissolution of 1,5-diphenylcarbazide after heat treatment and activated alumina as adsorbent for preconcentration

This work proposes the quantification of Cr (VI) ions in natural waters in trace level, using activated alumina (Al₂O₃) as preconcentration support, controlled in-line dissolution of the solidified chromophore diphenylcarbazide after heat treatment and spectrophotometric detection. The manifold ensures high sensitivity of analytical response, good repeatability, and stability. In this work, optimization of experimental conditions of a flow injection system was chosen as the parameters for greater sensitivity and better selectivity. The selected optimized conditions were 0.30 mol L^?1 for H₂SO₄ concentration, system flow rate as 0.40 mL min^?1, sample injection volume of 192.50 μL, 2 min for preconcentration time, and 0.10 mol L^?1 for eluent concentration. The analytical curves obtained for real sample analysis show linear range from 0.192 to 0.961 μM, linear correlation coefficient R?=?0.9997 and LOD?=?0.024 μM. The preconcentration factor of about four times was obtained through the passage of 800 μL of a standard solution containing 0.961 μM of Cr (VI) through mini-column of preconcentration followed by elution at 192.5 μL of NH₄OH 0.1 mol L^?1 solution. The solid chromogenic reagent presented high durability (weeks in daily use with mass of 0.0993 g) and good reproducibility in analytical signal. The reactivation of the mini-column of alumina should be executed after ten injections of eluent, using 800 μL of HCl 0.02 mol L^?1 solution in flow through the same. Each cycle of injection and elution of the sample takes about 5 min on the proposed terms. Despite the length of each cycle still be high, low concentrations can be detected using a technique of relatively low cost. This is due in part, the association dissolution of the chromogenic reagent directly in the line and the preconcentration step. Another important factor is the economy of reagent chromogenic, low generation of reject contributing to better quality of the environment, and the high potential for applications to work in field.     

Rate of occurrence of failures based on a nonhomogeneous Poisson process: an ozone analyzer case study

Atmospheric pollutant monitoring constitutes a primordial activity in public policies concerning air quality. In São Paulo State, Brazil, the São Paulo State Environment Company (CETESB) maintains an automatic network which continuously monitors CO, SO₂, NO _x , O₃, and particulate matter concentrations in the air. The monitoring process accuracy is a fundamental condition for the actions to be taken by CETESB. As one of the support systems, a preventive maintenance program for the different analyzers used is part of the data quality strategy. Knowledge of the behavior of analyzer failure times could help optimize the program. To achieve this goal, the failure times of an ozone analyzer—considered a repairable system—were modeled by means of the nonhomogeneous Poisson process. The rate of occurrence of failures (ROCOF) was estimated for the intervals 0–70,800 h and 0–88,320 h, in which six and seven failures were observed, respectively. The results showed that the ROCOF estimate is influenced by the choice of the observation period, t ₀?=?70,800 h and t ₇?=?88,320 h in the cases analyzed. Identification of preventive maintenance actions, mainly when parts replacement occurs in the last interval of observation, is highlighted, justifying the alteration in the behavior of the inter-arrival times. The performance of a follow-up on each analyzer is recommended in order to record the impact of the performed preventive maintenance program on the enhancement of its useful life.     

Genotoxic effects of the herbicide Roundup® in the fish Corydoras paleatus (Jenyns 1842) after short-term, environmentally low concentration exposure

The glyphosate-based herbicide, Roundup^®, is one of the most used pesticides worldwide. In concert with the advent of transgenic crops resistant to glyphosate, the use of this pesticide has led to an increase in agricultural yields. The objective of this study was to evaluate the genotoxic effect that the herbicide Roundup^® (at a concentration of 6.67 μg/L, corresponding to 3.20 μg/L glyphosate) can have on the fish Corydoras paleatus. Treatment groups were exposed for 3, 6, and 9 days, and effects were analyzed using the piscine micronucleus test (PMT) and comet assay. A group subjected to filtered water only was used as a negative control. The PMT did not show differences between the control and exposed groups for any of the treatment times. In contrast, the comet assay showed a high rate of DNA damage in group exposed to Roundup^® for all treatment times, both for blood and hepatic cells. We conclude that for the low concentration used in this research, the herbicide shows potential genotoxic effects. Future research will be important in evaluating the effects of this substance, whose presence in the environment is ever-increasing.