Available Water Sources Research Articles

Thematic issue: groundwater resources management

Groundwater plays a significant role in the overall circulation of water through the hydrologic cycle. Worldwide, groundwater sources constitute about 25% of total freshwater available, and in many areas, groundwater is the sole source of potable water. Groundwater has usually been considered as a readily available and safe source of water for domestic, agricultural and industrial uses. Groundwater supplies are not unlimited. Its use should be properly planned based on an understanding of the local hydrogeologic setting to ensure sustainable resources. In many areas, extraction of excessive quantities of groundwater has resulted in progressive depletion of resources and the decline of the local water table. Usage in excess of sustainable limits can lead to other adverse consequences: land subsidence, deterioration of groundwater quality, sea water intrusion, degradation of associated surface water streams, ecological damage, and negative impacts on human and animal health. With growing industrialization and other changes in land use, coupled with increased effluent from domestic, agricultural, and industrial growth, a gradual decline in groundwater quality is the common result. Expert, wellorganized water resources planning is the key to preserving water quality. Regional and local policies and strategies for groundwater development and management must be realistic and flexible to be effective for ensuring long-term use of this valuable resource. In this thematic issue, invited research from attendees of the international symposium on ‘‘Efficient Groundwater Resources Management’’, held in Bangkok, Thailand, February 16–18, 2009 are presented, as well as some other manuscripts on the subject. The theme of this important meeting, which was organized by the Department of Groundwater Resources under the Ministry of Natural Resources and Environment, Thailand was ‘‘Groundwater – The Challenge of Quantity and Quality for a Sustainable Future.’’ Co-Organizers were the Thai Hydrogeology Association and the Geological Society of Thailand. CoSponsors were the International Association of Hydrogeologists; UNESCO-International Hydrological Program; Coordinating Committee for Geosciences Programs in East and Southeast Asia; World Bank GW-MATE; and HydroGeoLogic Inc., USA. Manuscripts presented in this thematic issue focus on areas including effective assessment of groundwater opportunities and hazards; efficient groundwater management for urban and rural areas; emerging threats to groundwater quantity and quality; protecting groundwater resources; and groundwater regulation and governance, among other topics. Special thanks are extended to Ashim das Gupta, Oranuj Lorphrensri, and Sucharit Koontanakulvong for their service in helping coordinate this thematic issue.

Isotopic, hydrologic and geomorphologic approach for the rejuvenation of few drying springs in mountainous region of Dhouli Rao and Kandela, Himachal Pradesh, India

Springs are the only available source of water for domestic and agricultural use in mountainous regions of Dhouli Rao and Kandela in the Sirmaur district of Himachal Pradesh, India. These springs are mainly gravity, contact or fracture and solution tubular (Karst) type. Drying of springs during summer causes much hardship to the inhabitants of this region. Hence, environmental isotopes (2H, 18O, 3H) were employed along with hydrogeochemistry and geomorphology to identify the recharge zones of the drying springs. From the stable isotope data of rainwater, the altitude effect was estimated (−0.3 ‰ for δ18O per 100 m elevation) and used to determine the recharge zones of the drying springs (+1,000 to +1,430 m amsl). The geo-morphological setting of the valley indicated that either check dam, contour bunding or levees structures with gabion method of rainwater conservation can be implemented to augment the recharge of the springs.

Introductory editorial: advances in karst hydrogeology

Karst aquifers constitute 12 % of the global land surface and store water on which approximately 20–25 % of the world’s population depends, as it is stated in classical text books on karst. One-third of the surface area of Europe contains this type of aquifer, which supplies water to cities like London, Bristol, Paris, Montpellier, Vienna and Rome, to name just a few significant examples. In some countries, such as Slovenia and Austria, karst water contributes more than half of the drinking water supply and in many regions it is the only available source of fresh water. Moreover, karst aquifers are mostly upstream systems, acting as a water tower of fragile ecosystems that may be coastal and/ or correspond to urban areas subject to development. Karst areas also support unique ecosystems that are very rich in biodiversity, but their functioning, development and level of fragility remain largely unknown. Several karst systems are included in the UNESCO World Heritage list, and are characterised as strategic resources at local, national and international levels. The potential of karst areas in terms of hydro-geo-biodiversity, for instance, is widely recognised. These considerations illustrate the importance of the water stored in this type of medium and, therefore, the need for research into karst hydrogeology. Unlike porous or fissured formations, karst systems have a particular heterogeneous structure and behaviour, characterised by the concentration of groundwater flow through a network of karst conduits, enclosed within a less permeable matrix and connected to a local discharge area, the karst spring. This combination of areas of high hydraulic conductivity/low storage capacity (karst conduits) and medium to low hydraulic conductivity/medium to high storage capacity (fractures and matrix systems) means that contaminants may readily penetrate the subsurface, reaching groundwater and then being rapidly transported over large distances. Various research techniques have been developed, mainly based on the analysis of the natural response of karst aquifers, and include spring discharge (hydrographs), chemical composition (chemographs) and temperature and isotopes (both stable and radioactive). There has also been progress in the implementation of techniques such as dye tracers, with tracers (especially fluorescent ones) that are environmentally innocuous and provide a higher sensitivity. Recent experiments have been done with methods based on natural tracers, such as total organic carbon, natural fluorescence, turbidity and bacteria from the soil. The combined use of several of these methods allows the comparison of the results of various research programs and the ability to reach well-grounded conclusions. The specificity of the karst medium is fully accepted at all levels of hydrogeological knowledge, as shown by the fact that most of the international associations concerned with water, geological and environmental sciences have specific karst committees. One case is the Karst Commission of the International Association of Hydrogeologists (http://www.iah.org/karst), which organises many activities (conferences, meetings, training courses, publications, handbooks, etc.) on karst hydrogeology; in fact, this special issue is considered a contribution by the IAH Karst Commission. Moreover, there are specific international journals on karst (Acta Carsologica, Carbonates and Evaporites, International Journal of Speleology, Journal of Cave and Karst Studies), and contributions on this subject are published in many scientific journals, as occurs with this Environmental Earth Sciences special issue. In addition, B. Andreo (&) Department of Geology and Centre of Hydrogeology, University of Malaga, 28091 Malaga, Spain e-mail: andreo@uma.es

Home Range and Ranging Behaviour of Bornean Elephant (Elephas maximus borneensis) Females

BackgroundHome range is defined as the extent and location of the area covered annually by a wild animal in its natural habitat. Studies of African and Indian elephants in landscapes of largely open habitats have indicated that the sizes of the home range are determined not only by the food supplies and seasonal changes, but also by numerous other factors including availability of water sources, habitat loss and the existence of man-made barriers. The home range size for the Bornean elephant had never been investigated before.Methodology/Principal FindingsThe first satellite tracking program to investigate the movement of wild Bornean elephants in Sabah was initiated in 2005. Five adult female elephants were immobilized and neck collars were fitted with tracking devices. The sizes of their home range and movement patterns were determined using location data gathered from a satellite tracking system and analyzed by using the Minimum Convex Polygon and Harmonic Mean methods. Home range size was estimated to be 250 to 400 km2 in a non-fragmented forest and 600 km2 in a fragmented forest. The ranging behavior was influenced by the size of the natural forest habitat and the availability of permanent water sources. The movement pattern was influenced by human disturbance and the need to move from one feeding site to another.Conclusions/SignificanceHome range and movement rate were influenced by the degree of habitat fragmentation. Once habitat was cleared or converted, the availability of food plants and water sources were reduced, forcing the elephants to travel to adjacent forest areas. Therefore movement rate in fragmented forest was higher than in the non-fragmented forest. Finally, in fragmented habitat human and elephant conflict occurrences were likely to be higher, due to increased movement bringing elephants into contact more often with humans.

Giving them what they want: manipulating Argentine ant activity patterns with water

AbstractThe invasive success of the exotic Argentine ant [Linepithema humile (Mayr)] is often closely tied to year‐round availability of water sources. Previous studies suggest that the location of such water sources can strongly influence activity patterns of colonies and may be a key predictor of building infestations. We studied activity patterns of Argentine ants in relation to water and food resources in two open‐air structures (aviaries). In one series of manipulations, ant activity inside the aviaries was significantly reduced with the placement of numerous water sources around the outside. Inside activity increased again when the outside water sources were removed. A second series of manipulations involved the placement of water sources at targeted locations outside of the structures. Ant activity inside the aviaries consistently shifted significantly closer to these targeted sites. The results suggest that providing a reliable water source to Argentine ant colonies exterior to buildings can be a non‐chemical method of integrated pest management for reducing ant infestations. Independent of our manipulations, L. humile activity levels predictably declined with time of day, but these changes were uncorrelated with observed surface temperatures. In fact, activity was often noted at surface temperatures higher than those that cause worker mortality under laboratory conditions. This suggests that L. humile exhibits a consistent temperature‐independent circadian activity pattern of reduced foraging in afternoons relative to mornings.

Pitted rock surfaces on Mars: A mechanism of formation by transient melting of snow and ice

Pits in rocks on the surface of Mars have been observed at several locations. Similar pits are observed in rocks in the Mars‐like hyperarid, hypothermal stable upland zone of the Antarctic Dry Valleys; these form by very localized chemical weathering due to transient melting of small amounts of snow on dark dolerite boulders preferentially heated above the melting point of water by sunlight. We examine the conditions under which a similar process might explain the pitted rocks seen on the surface of Mars (rock surface temperatures above the melting point; atmospheric pressure exceeding the triple point pressure of H2O; an available source of solid water to melt). We find that on Mars today each of these conditions is met locally and regionally, but that they do not occur together in such a way as to meet the stringent requirements for this process to operate. In the geological past, however, conditions favoring this process are highly likely to have been met. For example, increases in atmospheric water vapor content (due, for example, to the loss of the south perennial polar CO2 cap) could favor the deposition of snow, which if collected on rocks heated to above the melting temperature during favorable conditions (e.g., perihelion), could cause melting and the type of locally enhanced chemical weathering that can cause pits. Even when these conditions are met, however, the variation in heating of different rock facets under Martian conditions means that different parts of the rock may weather at different times, consistent with the very low weathering rates observed on Mars. Furthermore, as is the case in the stable upland zone of the Antarctic Dry Valleys, pit formation by transient melting of small amounts of snow readily occurs in the absence of subsurface active layer cryoturbation.

Efectos de la 5-HT con pretratamiento de ciproheptadina sobre la estructura de la conducta alimentaria de las ratas

In the present study, we examined the effects of 5-HT in animals pretreated with cyproheptadine (5-HT receptor antagonist) on the patterns of feeding behavior of rats. The drugs were injected into the nucleus of paraventricular hypothalamus (NPV). The animals were maintainded on a self-selection feeding paradigm and provided wiht freely available ans separate sources of protein, carbohydrates, fat and water. The rats were kept at 21/ 1ºC on a 12-h light: 12-h dark cyle. Our results indicate that the administration of cyproheptadine into NPV attenuated the suppresive effect of 5-HT on carbohydrate intake, including the onset o the natural ( dark) feeding period.

Caries prevalence and its association with brushing habits, water availability, and the intake of sugared beverages

BACKGROUND. With Dental Caries being the most common disease amongst children in the world today, there is a need to fully understand risk factors that may be related to caries prevalence and how they could be best addressed. AIM. The aim of this study was to evaluate soda, juice, sugared-beverage intake, brushing habits, and community water source availability as they relate to the prevalence of both noncavitated and cavitated caries lesions in small rural villages in Mexico. DESIGN. The International Caries Detection and Assessment System (ICDAS) was used in children from small, isolated, villages in Mexico. Risk factors were assessed via questionnaires. RESULTS. Caries prevalence in the villages was very high, ranging from 94.7% to 100% of the children studied. The mean number of surfaces with lesions per child (D1MFS + d1mfs) having scores ≥1 (noncavitated and cavitated) ranged from 15.4 ± 11.1 to 26.6 ± 15.2. Many of the children reported drinking beverages containing sugar. CONCLUSIONS. Drinking sugared beverages, poor oral hygiene habits, and lack of access to tap water were identified as risk factor for caries in this sample of residents of rural Mexico.

Sexual segregation and use of water by bighorn sheep: implications for conservation

AbstractMales and females of most dimorphic ruminants segregate outside the mating season, which may necessitate that conservation efforts focus on differential resources used by the sexes. Dimorphic bighorn sheep Ovis canadensis are one of the rarest ungulates in North America with some populations listed as endangered. Water sources are important for the persistence of populations of bighorns, especially in a changing climate. Understanding whether the sexes use different water sources could influence the conservation of this species and the habitats they occupy; however, little research exists regarding this important topic. We tested hypotheses relating to use of water sources by reintroduced male and female bighorns in Utah, USA. We investigated whether use of this resource differed across seasons by sex, and if sexes used water more during drought compared with non‐drought conditions. Bighorns used small, adjacent core areas during segregation, and males and females used different sources of water during that time. Males visited water sources used by females more during aggregation. Males and females used water sources more in summer, and males visited water sources more during rut than did females. Males and females did not use water sources more during drought compared with non‐drought conditions; however, sexes visited water sources more during the season following drought than following non‐drought conditions, indicating a time‐lag in use of this resource. Our results highlight the importance of water sources used by sexes of bighorns, and indicate that the existing criterion for distance of bighorn reintroductions from water may be inadequate for successful establishment of populations. We recommend conservationists assess availability of water sources near habitat used by male and female ungulates before conserving and manipulating habitat, siting artificial sources of water and reintroducing animals.

Analisis Karakteristik Parameter Hidrologi akibat Alih Fungsi Lahan di Daerah Sukoharjo melalui Citra Landsat Tahun 1997 dengan Tahun 2002

The Study, carried out Sukoharjo, deals with the effect of land function change from 1997 to 2002 toward the change of chosen hydrological parameters. The hydrological parameter constituses the coefficient runoff (C), the extra soil water (id), and the amount of constant stream (Wa). The process of land function the change is searched by using landsat image composit RGB (Red Green Blue) 452. Meanwhile, the aims of the study are (1) to determine the types and distribution for the process of land function change, and (2) to analyze the change of coefficient value runoff (C), the extra soil water (Id), and the amount of constant stream (Wa) within the area of research. The result of the study shown that there are many types of land function change, which occurred in almost all the area of research except the one type coming from the river becoming wet/dry rice field/residence/forest of which only occurred in Nguter sub district. The condition because of the straightening Bengawan Solo River in the sub district, cousequenly, the land function change proceses from the river into the land and vice versa. Moreover, of the 7 types of land function change in the area of research, the widest type of land function change covering the whole district is a change from forest/ horticulture/dry or wet rice field into residence. The effect of such a change has also caused a change in the characteristics of chosen hydrological parameter. Such a change can be seen from the value C, Id, and Wa. Furthermore, the change can be clarified as follow: the value C and Wa tend to rise while Id tends to decrease. This mean that the land function change has resulted in great abundant and decrease of water absorbed in the soil. In general, the availability of water source within the area can still be supplied from the seemingly increased constant stream. Such a condition might be caused by the ratio between the built land and the proportional open land of which about > 30 % of the whole space.

Causes of Water Supply Problems in Urbanised Regions in Developing Countries

An analysis was made of the underlying factors leading to water supply problems in urbanized regions in developing countries. Three interrelated factors were identified and described: (1) a high rate of population growth, (2) lack of investments in water supply infrastructure, and (3) the upper limit imposed by the availability of water sources. This background allows understanding failures in water supply systems in large cities in developing countries. Each of these factors may individually compromise water supply, but in many cases the context is a complex interplay of these factors, often fed by political or military instability and poverty. Sanitation is often closely related to water supply systems, although the situation is generally worse. Based on this analysis, an evaluation was made of water supply in Kinshasa, D.R. Congo, in comparison with the historical case of London, UK, and the development of Los Angeles, CA, USA. In addition, reference is made to the case of Tokyo, Japan. From this comparison, opportunities and threads for Kinshasa can be shown.

An Evaluation of Radarsat-1 and ASTER Data for Mapping Veredas (Palm Swamps).

Veredas (palm swamps) are wetland complexes associated with the Brazilian savanna (cerrado) that often represent the only available source of water for the ecosystem during the dry months. Their extent and condition are mainly unknown and their cartography is an essential issue for their protection. This research article evaluates some of the fine resolution satellite data both in the radar (Radarsat-1) and optical domain (ASTER) for the delineation and characterization of veredas. Two separate approaches are evaluated. First, given the known potential of Radarsat-1 images for wetland inventories, the automatic delineation of veredas is tested using only Radarsat-1 data and a Markov random fields region-based segmentation. In this case, to increase performance, processing is limited to a buffer zone around the river network. Then, characterization of their type is attempted using traditional classification methods of ASTER optical data combined with Radarsat-1 data. The automatic classification of Radarsat data yielded results with an overall accuracy between 62 and 69%, that proved reliable enough for delineating wide and very humid veredas. Scenes from the wet season and with a smaller angle of incidence systematically yielded better results. For the classification of the main vegetation types, better results (overall success of 78.8%) were obtained by using only the visible and near infrared (VNIR) bands of the ASTER image. Radarsat data did not bring any improvement to these classification results. In fact, when using solely the Radarsat data from two different angle of incidence and two different dates, the classification results were low (50.8%) but remained powerful for delineating the permanently moist riparian forest portion of the veredas with an accuracy better than 75% in most cases. These results are considered good given the width of some types often less than 50 m wide compared with the resolution of the images (12.5 - 15 m). Comparing the classification results with the Radarsat-generated delineation allows an understanding of the relation between synthetic aperture radar (SAR) backscattering and vegetation types of the veredas.

AN INTEGRATED ASSESSMENT OF THE SUITABILITY OF DOMESTIC SOLAR STILL AS A VIABLE SAFE WATER TECHNOLOGY FOR INDIA

Improving access to safe drinking water can result in multi-dimensional impacts on people's livelihood. This has been aptly reflected in the Millennium Development Goals (MDG) as one of the major objectives. Despite the availability of diverse and complex set of technologies for water purification, pragmatic and cost-effective use of the same is impeding the use of available sources of water. Hence, in country like India simple low-energy technologies such as solar still are likely to succeed. Solar stills would suffice the basic minimum drinking water requirements of man. Solar stills use sunlight, to kill or inactivate many, if not all, of the pathogens found in water. This paper provides an integrated assessment of the suitability of domestic solar still as a viable safe water technology for India. Also an attempt has been made to critically assess the operational feasibility and costs incurred for using this technology in rural India.

Fresh Water from the Sea and Other Uses of Deep-Ocean Water for Sustainable Technologies

Everyone and everything needs fresh water, and many sources of this precious commodity are in peril. In coastal areas, desalination of ocean water is an option, but it can be expensive, consume power, and generate waste. In recent times, the idea that the oceans can provide an “endless bounty” has been called into serious question with such evidence as the collapse of many fisheries and the growth of “dead zones” from waste and nutrient runoff. However, one resource of the ocean that may be practically inexhaustible is its reservoir of cold. Drawn from a thousand meters or more from the surface, Deep Ocean Water (DOW), barely above the freezing point, can be used in many ways, among them condensing fresh water from humid air in tropical environments. This fresh water resource requires little energy to produce, requires no chemicals, and produces no waste. It is most suitable for use in tropical islands and coastal deserts, which are generally near a source of cold ocean water, have warm, humid air, and little available fresh water. Further, there are other uses for the cold of DOW, enhancing agriculture in some surprising ways, and even supporting aquaculture. The Common Heritage Corporation of Hawai'i is investigating economically feasible development of this resource and other DOW technologies around the world.

Response Matrix Minimization Used in Groundwater Management with Mathematical Programming: A Case Study in a Transboundary Aquifer in Northern Greece

Groundwater has always been considered to be a readily available source of water for domestic, agricultural and industrial use. The last decades, the lack of policymaking for the utilization of groundwater, has led to overexploitation in many areas. The cooperation of a wide range of scientists such as mathematicians, engineers, computer scientists, environmentalists and economists – operation researchers, have led to the design and construction of commercial computer programs concerned on water management and specifically on the optimal distribution of limited water resources using groundwater management models. These combined models, via simulation and optimization algorithms, result in one optimal solution through operations research and mathematical programming methods. The groundwater management models are based on the method of space superposition or the combination of space and time superposition for steady and unsteady state problems, respectively. In the present study, an algorithm is presented, which minimizes the dimension of the response matrix, concerning on two assumptions: the first is the added fixed cost which represents the water supply pumping well and the second is the removal of time superposition. The study area is a transboundary phreatic aquifer in Northern Greece, in the area of Eidomeni, a small Hellenic village just on the borderline with FYROM. The aquifer has a total area of 10,84 km2, 26 operating – pumping wells, which the 9 of them consist control points of the hydraulic head. The number of the management periods is 12 months.

Ancient Egyptian doctors and the nature of the biblical plagues

Paragraph 55 of the London Medical Papyrus describes burns derived from red waters and which later became infected with larvae in the wounds. The prescribed treatment for the burn is unusual as it calls for no rinsing and requires bandaging with alkaline materials only. Refraining from washing in the Nile (the single most readily available source of water in ancient Egypt), and the use of alkali-neutralizing agents indicates that the red caustic waters came from the river, and were acid in nature. A red, acid Nile is consistent with the first biblical plague of Egypt, which killed fish, and kept people from drinking from the river. In turn, the sulfate-laced waters of the medical document also offer a plausible insight into the subsequent biblical plagues. Amphibians would have stayed away from the deadly river, left to die on the banks, just as described in the second biblical plague. Similarly, the larvae in the wounds mentioned by the medical document re-echo the third and fourth biblical plagues: the kînnîm invertebrates and the subsequent 'arob (varied insects) are consistent with larvae and the subsequent adults thereof. In pre-industrial Ancient Egypt, sulfates from a massive volcanic fall out provide the simplest and most exhaustive origin for such waters. A massive precipitation that would account for the waters in the medical document and the biblical texts is known from sediments at the bottom of lakes along the Nile Delta. The site is downwind from the island of Santorini, and the deposit of volcanic ashes took place during the Middle Bronze Age, i.e. at a time consistent with the eruption at the Greek volcanic island.

Subsistence farming and conservation constrains in coastal peat swamp forests of the Kosi Bay Lake system, Maputaland, South Africa

Maputaland is a region of exceptionally rich biodiversity located in the north-eastern corner of Kwazulu-Natal and forms the southern most tip of the Mozambique coastal plain. It can be considered as the most southern end of the tropics in Africa and consequently many tropical species reach their southern most distribution boundary here. Maputaland is the largest peat containing region in South Africa with 60 % of the country’s peat present therein. Coastal peat swamps forests are more abundant in Maputaland than anywhere else in South Africa, but remain poorly studied as far as their vegetation composition, structure, functioning, and the nature and impact of exploitation on them are concerned. In this ongoing study an initial vegetation and environmental dataset of May 2003 was used to assess the impact of subsistence farming, predominately with madumbes (Colocasia esculenta) and bananas (Musa xparadisiaca), on coastal peat swamp forests. A TWINSPAN numerical classification resulted in the identification of 10 vegetation groups, exhibiting a gradient from pristine to highly disturbed peat swamp forests. The pristine peat swamp forest group is separated on the degree of wetness, ranging from wet to dry peat swamp forests, while the highly disturbed group is divided according to the presence or absence of active gardening. A Detrended Correspondence Analysis (DCA ordination) determined anthropogenic practices involving tree felling and peat draining as the main factors responsible for peat swamp forest habitat modification. The change in swamp forest structure and peat hydrology critically threatens the continued existence and ecological functioning of these systems. This impacts negatively on habitat and biodiversity loss and will eventually deprive the rural community of a sustainable gardening environment, bring about a change in the lake system’s nutrient balance, and even reduce available sources of clean and fresh water. The situation poses an urgent conservation challenge for the conservation agency and local community whose livelihood is intricately interwoven and pivoted around their peat swamp forest environments. Before progress can however be made trust needs to be established between the different stakeholders, looking beyond solutions of complete exclusion, but rather to mutual cooperation, involving practices such as wise use gardening management.

Treated sewage effluent (water) potential to be used for horticultural production in Botswana

Botswana being semi-arid and arid country, the provision of drinking water and water for agricultural production is becoming increasingly scarce and expensive. Measures that can augment the available sources of water or measures that can reduce the demand on potable water should be given serious consideration. Horticulturists have incorporated new technology into many of their production programs, which has enabled them to grow more horticultural crops with less water; however, more effort is needed. Techniques such as drip irrigation, sensors, growing plants with low water requirements, timing and scheduling of irrigation to the growth needs of the plant, mulching, and establishing a minimum water quality standard for horticultural crops must be used to stretch agricultural water supplies. Recycling agricultural water and using treated municipal sewage effluent is a viable option for increasing horticultures’ future water supply in Botswana. Agriculture wastewater and sewage effluents often contain significant quantities of heavy metals and other substances that may be toxic to people but beneficial to horticultural crops. However, before sewage effluent can be used for commercial production of vegetables and fruits, research must be undertaken to determine whether there is accumulation of heavy metals and faecal coliforms in the edible portion of the horticultural produce which may be detrimental to human health 15–20 years later. Research must be undertaken to assess the impact of sewage effluent on soil physical, chemical properties and environment after continued use.

Environmental influences on anuran sound communication

Studies of anuran vocal behavior in the South American temperate forest may represent the southernmost influence of Robert Capranicas comparative approach to sound communication. Vocalizations of leptodactylid frogs in this region exhibit patterns of propagation characteristic for different microhabitats. Calls containing frequencies above about 1 kHz experience higher attenuations in bogs as compared to marshes, irrespective of the species native environment. A similar lack of optimal relationships between signal structure and habitat properties for call propagation occurs in sound environments other than the temperate austral forest, as indicated by joint studies with colleagues from Cuba in Caribbean tropical forests and from Spain in European Mediterranean habitats. Anurans from southern Chile calling in bogs have peculiar acoustic adaptations: males call from burrows inside which the calls of neighboring cospecifics are amplified considerably. This effect potentially counteracts the constraints for signal propagation of sound-attenuating environments. The evidence presented indicates that anuran calls have not been subjected to environmental selection pressures, to the extent vocalizations of other vertebrates have. Dispersion of anurans is limited by availability of water sources, but males can choose locations favoring signal broadcast and reception in their relatively restricted breeding areas. [Work supported by FONDECYT Grant No. 1010569.]

Effect of 5-HT in mianserin-pretreated rats on the structure of feeding behavior

The present study examined the effects of intra-PVN serotonin injection in mianserin-pretreated rats at the onset of the dark phase of light cycle on the structure of feeding behavior. The drugs were injected into the paraventricular nucleus (PVN) of the hypothalamus. The animals were maintained in a self-selection feeding paradigm and provided with freely available and separate sources of protein, carbohydrate, fat and water. The suppressive effect of 5-HT on carbohydrate intake was attenuated by mianserin at the beginning of the active (dark) feeding period. Mianserin-pretreatment increased the duration of carbohydrate and protein intake, but it was unable to block the effect of 5-HT on meal frequency and local rate of carbohydrate consumption. The present data suggests that carbohydrate intake may be in part mediated by postsynaptic 5-HT 2A/2C receptors. However, the temporal characteristics of carbohydrate ingestion are mediated by another subpopulation of 5-HT receptors in the PVN and indicates a possibly adrenergic influence.