Bioassessment of Streams using Macroinvertebrates: Are the Chironomidae Necessary?

Median hardness and sodium levels in groundwater were calculatedfor 244 Texas counties from measurements at 7728 water wells.The data were mapped and analyzed with a geographic informationsystem (GIS). County median hardness levels varied widely, from4–2304 mg L^-1. More than 60% of the counties had hardnessmedians above 180 mg L^-1. County medium sodium concentrationsranged from 6–1170 mg L^-1, with more than 90% of those valuesexceeding 20 mg L^-1. There was a significant positive correlationbetween hardness and sodium concentrations in six of Texas' ninemajor aquifers. A significant negative correlation betweenhardness and sodium was observed in two aquifers. Severalfactors control hardness and sodium variations in Texas aquifers including rock/sediment composition, groundwaterchemical evolution, and seepage from nearby formations. Probablehuman controls include agricultural return flow andpumping-induced saltwater intrusion.     

Are Artificial Barrages Necessary to Prevent Saline Incursion? A Modelling Approach to Restore the Healthy Ecosystem of the Vembanad Lake

Environmental Modeling & Assessment - The Thanneermukkom Bund was constructed to prevent salt water intrusion in the low lying areas of the Kuttanad region which increase the paddy cultivation...     

Atmospheric Change and the Diversity of Aquatic Invertebrates: Are We Missing the Boat?

The response of natural systems to atmospheric change may depend critically on species diversity and on the genetic diversity (variability) found within their respective populations. Yet, most surveys of aquatic invertebrates account for neither. This may be of particular concern for benthic populations in running waters because of the considerable variability and the fragmentary nature of these habitats (e.g. isolated watersheds). In such habitats, species with limited genetic variability and/or limited dispersal capabilities (genetically differentiated populations) may be unable to track rapid environmental change, and may be more susceptible to climatic perturbations. We present a conceptual framework to illustrate some of the potential problems of ignoring population genetics when considering the impacts of global atmospheric change. We then review a simple method to assess population genetic structure and we evaluate available data on the genetic structure of North American stream invertebrates. These data indicate that benthic taxa often consist of genetically differentiated local populations, or even previously unknown species. Accordingly, our limited knowledge of population structure among benthic invertebrates may result in the unwitting loss of genetic and/or species diversity. Enhanced taxonomic research incorporating molecular techniques is clearly warranted. Conservation strategies based on the preservation and remediation of a diversity of aquatic habitats are likely to be our best means of ensuring species and genetic diversity of invertebrate taxa.     

Determination of Henry’s Law Constant of Formaldehyde as a Function of Temperature: Application to Air–Water Exchange in Tahtali Lake in Izmir, Turkey

The Henry's law constant (H) is an important parameter in predicting the transport, behavior and fate of organic compounds in environment. H is also required to model the air-water exchange of chemicals. Henry's law constant of formaldehyde (HCHO) was determined at six temperatures (50, 40, 30, 20, 10, and 5 degrees C) using a bubble-column technique. The apparent Henrys law constant (H*) values were strongly correlated to inverse of temperature (1/T, K) and the following relationship was obtained: In H* = (-1,641.3/T)-3.089. Seven concurrent ambient air and aqueous samples were also collected between October 11-17, 2005 at a sampling site located on the shoreline of Tahtali dam Lake in Izmir, Turkey to determine the magnitude and direction (deposition or gas-out) of HCHO flux. In all cases, the modeled gas-phase flux was positive (average +/- SD, 3,181 +/- 408 microg m(-2) day(-1)) indicating that atmospheric HCHO deposited to the Tahtali Lake.     

Analysis of the environmental impact on a stream: is only tannery to blame?

The contribution of wastewater from a tannery industry to the pollution of a stream was investigated. The main parameters studied were biochemical oxygen demand, chemical oxygen demand, chromium, dissolved oxygen, fecal and total coliforms, nitrogen, oils and greases, pH, phosphorous, sulfides, suspended solids, turbidity, and volatile solids. Three sampling points were located: (1) at the discharge point of tannery wastewater, (2) 50 m upstream, and (3) 80 m downstream of discharge point. Also was investigated the pollution at the stream source.     

Temporal and spatial trends in water quality of Lake Taihu,China: analysis from a north to mid-lake transect, 1991–2011

Interpretations of state and trends in lake water quality are generally based on measurements from one or more stations that are considered representative of the response of the lake ecosystem. The objective of this study is to examine how these interpretations may be influenced by station location in a large lake. We addressed this by analyzing trends in water quality variables collected monthly from eight monitoring stations along a transect from the central lake to the north in Lake Taihu (area about 2,338 km²), China, from October 1991 to December 2011. The parameters examined included chlorophyll a (Chl a), total nitrogen (TN), and total phosphorus (TP) concentrations, and Secchi disk depth (SD). The individual variables were increasingly poorly correlated among stations along the transect from the central lake to the north, particularly for Chl a and TP. The timing of peaks in individual variables was also dependent on station location, with spectral analysis revealing a peak at annual frequency for the central lake station but absence of, or much reduced signal, at this frequency for the near-shore northern station. Percentage annual change values for each of the four variables also varied with station and indicated general improvement in water quality at northern stations, particularly for TN, but little change or decline at central lake stations. Sediment resuspension and tributary nutrient loads were considered to be responsible for some of the variability among stations. Our results indicate that temporal trends in water quality may be station specific in large lakes and that calculated whole-lake trophic status trends or responses to management actions may be specific to the station(s) selected for monitoring and analysis. These results have important implications for efficient design of monitoring programs that are intended to integrate the natural spatial variability of large lakes.     

PCDD/F contamination on surface soil in the vicinity of a hazardous waste incinerator: is it possible a different trend?

This study is the first to investigate the contamination of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) on surface soils in the vicinity of the first hazardous waste incinerator of Turkey. In the study, 24 soil samples were taken from a 1625-m-radius circle whose center is the stack of the incinerator. This process was repeated 1 year later. Since the acquired average PCDD/F concentrations of the two sampling campaigns (0.05 and 0.02 ng WHO-toxic equivalent (TEQ)/kg) were meaningfully low compared to the related literatures, a new sampling campaign was carried out to control this inconsistency, but this time in a foreign laboratory (0.56 ng WHO-TEQ/kg). In the same period, eight gas samples were taken from the stack under different operational conditions of the facility. According to the evaluations of the findings, the geographical-meteorological data of the study area and the specific operational conditions of the facility corroborate the concentrations of the first and the second soil samplings rather than the third one. The major underlying reason for the inconsistency of the soil concentrations may be the fact that the data analysis procedures used by the laboratories are different. The author suggests a hypothesis which argues that the soils in the vicinity of a hazardous waste incinerator may have significantly lower concentration levels than in related literatures.     

An environmental impact assessment of economic complexity and energy consumption: Does institutional quality make a difference?

The relationship between ecological footprint and economic complexity has important policy implications for environmental sustainability. Furthermore, institutional quality can be an imperative tool to ensure environmental sustainability, and it may also moderate the nexus between economic complexity and ecological footprint. Therefore, this study investigates the linkage between economic complexity, institutional quality, disaggregated energy consumption, and economic growth on environmental degradation in emerging countries from 1984 to 2017. In addition, it also probes the moderating effect of institutional quality in the nexus between economic complexity and footprint. To do so, the study applies an advanced econometric approach, cross-sectional autoregressive distributed lags (CS-ARDL) estimator, for short-run and long-run estimation, that allows heterogeneity in the slope parameters and dependencies across countries. The analytical outcomes demonstrate that economic complexity increases environmental degradation by exacerbating ecological footprint, while a high level of economic complexity mitigates ecological footprint. The findings of the study unfold that institutional quality supports environmental sustainability by reducing the ecological footprint. The outcomes also indicated that institutional quality promotes environmental sustainability by moderating the nexus between economic complexity and ecological degradation. Moreover, renewable energy is found to decrease ecological footprint, whereas non-renewable energy use leads to intensifying the ecological footprint. It was also found that there is an inverted u-shaped association between ecological footprint and economic growth. Based on the results, the study suggests that emerging countries should accelerate economic complexity along with a stronger institutional framework to combat environmental issues without compromising sustainable economic growth.     

Geoprocessing applied to the assessment of environmental noise: a case study in the city of Sorocaba, S?o Paulo, Brazil

Noise mapping has been used as an instrument for assessment of environmental noise, helping to support decision making on urban planning. In Brazil, urban noise is not yet recognized as a major environmental problem by the government. Besides, cities that have databases to drive acoustic simulations, making use of advanced noise mapping systems, are rare. This study sought an alternative method of noise mapping through the use of geoprocessing, which is feasible for the Brazilian reality and for other developing countries. The area chosen for the study was the central zone of the city of Sorocaba, located in São Paulo State, Brazil. The proposed method was effective in the spatial evaluation of equivalent sound pressure level. The results showed an urban area with high noise levels that exceed the legal standard, posing a threat to the welfare of the population.     

Assessment of transboundary environmental effects in the Pearl River Delta Region: Is there a role for strategic environmental assessment?

China's EIA Law does not require transboundary proposals to be assessed, despite recognition of this globally, for example in the Espoo Convention and Kiev Protocol, and in the European EIA and SEA Directives. In a transboundary context assessment within a state is unusual, as regulating these effects is primarily about the relationship between states. However where a state has more than one legal system such as in the Pearl River Delta (PRD) Region of southern China, transboundary effects should also be addressed. Yet despite the geographical connections between Guangdong Province in mainland China (where the EIA Law applies) and the Hong Kong and Macau Special Administrative Regions (which have their own provisions, neither of which requires transboundary assessments), EIA and SEA are carried out separately. Coordinated or joint approaches to transboundary assessment are generally absent, with the legal autonomy of Hong Kong and Macau a major constraint. As a result institutional responses at the policy level have developed. The article considers global experiences with regulating transboundary EIA and SEA, and analyses potential application to land use, transport and air and water planning in the PRD Region. If applied, benefits may include prevention or mitigation of cumulative effects, broader public participation, and improvements to environmental governance. The PRD Region experience may encourage China to conduct and coordinate EIA and SEA processes with neighbouring states, which has been non-existent or extremely limited to date.     

Kelp as a Bioindicator: Does it Matter Which Part of 5 M Long Plant is Used for Metal Analysis?

Kelp may be useful as a bioindicator because they are primary producers that are eaten by higher trophic level organisms, including people and livestock. Often when kelp or other algae species are used as bioindicators, the whole organism is homogenized. However, some kelp can be over 25 m long from their holdfast to the tip of the blade, making it important to understand how contaminant levels vary throughout the plant. We compared the levels of arsenic, cadmium, chromium, lead, manganese, mercury and selenium in five different parts of the kelp Alaria nana to examine the variability of metal distribution. To be useful as a bioindicator, it is critical to know whether levels are constant throughout the kelp, or which part is the highest accumulator. Kelp were collected on Adak Island in the Aleutian Chain of Alaska from the Adak Harbor and Clam Cove, which opens onto the Bering Sea. In addition to determining if the levels differ in different parts of the kelp, we wanted to determine whether there were locational or size-related differences. Regression models indicated that between 14% and 43% of the variation in the levels of arsenic, cadmium, chromium, manganese, mercury, and selenium was explained by total length, part of the plant, and location (but not for lead). The main contributors to variability were length (for arsenic and selenium), location (mercury), and part of the plant (for arsenic, cadmium, chromium and manganese). The higher levels of selenium occurred at Clam Cove, while mercury was higher at the harbor. Where there was a significant difference among parts, the holdfast had the highest levels, although the differences were not great. These data indicate that consistency should be applied in selecting the part of kelp (and the length) to be used as a bioindicator. While any part of Alaria could be collected for some metals, for arsenic, cadmium, chromium, and manganese a conversion should be made among parts. In the Aleutians the holdfast can be perennial while the blade, whipped to pieces by winter wave action, is regrown each year. Thus the holdfast may be used for longer-term exposure for arsenic, cadmium, chromium and manganese, while the blade can be used for short-term exposure for all metals. Cadmium, lead and selenium were at levels that suggest that predators, including people, may be at risk from consuming Alaria. More attention should be devoted to heavy metal levels in kelp and other algae from Adak, particularly where they may play a role in a subsistence diets.