Water resources issues of small island developing states

The water resources of most small island developing states (SIDS) are often very limited and require special consideration to ensure that they are developed and managed in a sustainable manner. Many small islands, typically located in the humid tropics, have no surface water resources and rely on limited groundwater resources in the form of thin freshwater lenses. The exposed location of small islands makes them particularly vulnerable to natural disasters such as cyclones, floods and droughts. Pollution from population centres and from agricultural and other activities is an increasing problem. This article provides an overview of the water resources of small islands, and the main problems and issues related to water resources. Some suggested solutions, based on practical experiences, are offered for water resource assessment and monitoring programmes, and water resource development. Water resource policy, planning and management issues are also addressed, and suggested approaches for resolving some of the major water resource problems presented.     

QuEChERS-超高效液相色谱-串联质谱法测定鱼血清中的精神活性物质

本文建立了一种同时测定鱼血清中19种精神活性物质的分析方法.该方法基于QuEChERS方法对样品进行提取和净化,待测物采用超高效液相色谱-串联质谱法(UPLC-MS/MS)进行分析,检测的19种精神活性物质均采用同位素内标法定量.该方法的方法检测限(MDL)范围为0.02-0.06 ng.mE-1,基质效应处于76.7...     

Determination of Cadmium and Copper in Fish Samples from Sir And Menzelet Dam Lake Kahramanmaraş, Turkey

The cadmium and copper levels were determined in the total of 126 fish samples which belongs to five fish species collected from Sır and Menzelet Dam Lakes in Kahramanmaraş Province by Atomic Absorption Spectrophotometer. The concentrations of heavy metals were expressed as ppm wet weight of tissue. The mean levels of cadmium and copper in muscle, liver and gill tissues of Cyprinus carpiofrom the Menzelet Dam were found as 0.27, 0.91, 1.49 and 0.94, 1.2, 1.05, respectively. The mean levels of Cd in the muscle tissues of Leuciscus cephalusfrom the Menzelet Dam were found 0.32 ppm, Cd wasn't found in tissues of liver and gill. The mean levels of Cu in the muscle, liver and gill tissues were found as 3.17 ppm, 1.19 ppm, 0.96 ppm, respectively. The mean levels of the Cd and Cu in muscle and gill tissues of Acanthobrama marmid from the Sır Dam were found as 1.28, 2.64 and 0.72, 0.08, respectively. The levels of the Cd and Cu in muscle tissues of Cyprinus carpiofrom the Sır Dam were found 0.87 and 0.02 ppm, respectively. The mean levels of the Cd and Cu in the muscle and gill tissues of Chondrostoma regium from the Sır Dam were found to be 0.80, 2.62 and 0.67, 1.34 ppm, respectively. The mean levels of the Cd in the muscle tissues of the Silurus glanis was found as 0.60 ppm. In the muscle of the Silurus glanis from the Sır Dam, Cu was not found. The Sır Dam is more polluted than the Menzelet Dam from the point of Cd but less polluted than the Menzelet Dam From the point of Cu. A relationship was determined between species and their habitating region in terms of the levels reflected metal residues. In this study it was emphasized that the amounts of Cd and Cu in the samples were low, however, seas, lakes, rivers, soil, air and consumed foods etc. has to be controlled routinely.     

Evaluation of an Exposure Assay to Measure Uptake of Sediment Pah by Fish

The ecological risks of polynuclear aromatic hydrocarbons (PAH) in aquatic sediments will vary with both toxicity and bioavailability to aquatic biota. While there are standardized protocols to test the acute toxicity of sediment-borne compounds to aquatic invertebrates, there are none for assessing bioavailability to fish. We found that sediment-borne PAH caused an exposure-dependent induction of cytochrome P450 (CYP1A) enzymes in rainbow trout (Oncorhynchus mykiss) fingerlings exposed in semi-static 96 h bioassays, as shown by increased activity of ethoxyresorufin-o-deethylase (EROD). Assuming that PAH are taken up by trout due to partitioning from organic and inorganic constituents of sediments, we tested the effect of different test variables on bioaccumulation using induction as an index of exposure. EROD activity increased with exposure of fish to increasing volumes of sediments containing PAH, i.e., with increasing ratios of sediment to water. Uptake of single compounds from sandy sediments did not differ from uptake from clay or low organic (7% LOI — loss on ignition) sediments, but decreased when organic content was very high (58% LOI). Maximum induction was observed within 24~h of exposure and at 7.5^C relative to 15, 22, or 28^C. Storage and handling techniques had minor effects on sediment EROD induction potency. Absolute EROD activity was greater in white sucker (Catostomus commersoni) a benthic species, than in trout, a pelagic species. However, when basal (negative control) activity was accounted for, there was no difference in response between the species. Together, these experiments provide a basis for developing a standard protocol to test the bioavailability to fish of sediment-borne PAH.     

A Fish-Based Index of Biotic Integrity to Assess Intermittent Headwater Streams in Wisconsin, USA

I developed a fish-based index of biotic integrity (IBI) to assess environmental quality in intermittent headwater streams in Wisconsin, USA. Backpack electrofishing and habitat surveys were conducted four times on 102 small (watershed area 1.7–41.5 km²), cool or warmwater (maximum daily mean water temperature ≥22 C), headwater streams in spring and late summer/fall 2000 and 2001. Despite seasonal and annual changes in stream flow and habitat volume, there were few significant temporal trends in fish attributes. Analysis of 36 least-impacted streams indicated that fish were too scarce to calculate an IBI at stations with watershed areas less than 4 km² or at stations with watershed areas from 4–10 km² if stream gradient exceeded 10 m/km (1% slope). For streams with sufficient fish, potential fish attributes (metrics) were not related to watershed size or gradient. Seven metrics distinguished among streams with low, agricultural, and urban human impacts: numbers of native, minnow (Cyprinidae), headwater-specialist, and intolerant (to environmental degradation) species; catches of all fish excluding species tolerant of environmental degradation and of brook stickleback (Culaea inconstans) per 100 m stream length; and percentage of total individuals with deformities, eroded fins, lesions, or tumors. These metrics were used in the final IBI, which ranged from 0 (worst) to 100 (best). The IBI accurately assessed the environmental quality of 16 randomly chosen streams not used in index development. Temporal variation in IBI scores in the absence of changes in environmental quality was not related to season, year, or type of human impact and was similar in magnitude to variation reported for other IBI's.     

Bioaccumulation of Some Heavy Metals in Different Tissues Of Dicentrarchus Labrax L, 1758, Sparus Aurata L, 1758 And Mugil Cephalus L, 1758 From the ÇamlIk Lagoon of the Eastern Cost Of Mediterranean (Turkey)

In this study, bioaccumulation of the heavy metals (Fe, Zn, Cd) in the liver, gill, gonad and muscle tissues of Dicentrarchus labrax, Mugil cephalus and Sparus aurata were investigated seasonally. Camlik is the important fisheries lagoon located in The Iskenderun Bay, Mediterranean coast of Turkey. Due to heavy industrial and agricultural activities in the region, the bay has the polluted coastal waters of Turkey. Therefore, the levels of cadmium, zinc, iron were determined in the muscle in each species because of its importance for human consumption and also the liver, gill, gonad were analysed since these organs tend to accumulate metals. Heavy metal levels were found generally higher in the liver and gill than the gonad and muscle tissues in three species; the levels of all metals in a given tissue were generally higher in Mugil cephalus than the other two species. Data collected in this study suggest that Camlik lagoon is affected by a relatively metal pollution. The concentrations of Zn concentrations in the muscle tissues exceeded the acceptable levels for a food source for human consumption and other metals in the edible parts of the investigated fish were in the permissible safety levels for human uses.     

Metal Concentrations in Fish Species from the Northeast Mediterranean Sea

Samples of Mugil cephalus and Mullus barbatus were collected in the Northeast Mediterranean coast of Turkey the contents of cadmium, copper, iron, zinc and lead in the liver, gill and muscle tissues were determined by atomic absorption flame spectrophotometry.Except for lead, highest levels of each metal were found in the liver and this was followed by the gill and muscle in both species. Among the metals analyzed, Cu, Zn and Fe were the most abundant in the different tissues while Cd and Pb were the least abundant both in M. cephalus and M. barbatus. Seasonal changes in metal (Cd, Cu, Pb, Fe and Zn) concentration were observed in the tissues of both species, but these seasonal variations may not influence consumption advisories. In general, the highest concentrations were detected for all metals in summer.     

Integrating Human Impacts and Ecological Integrity into a Risk-Based Protocol for Conservation Planning

Conservation planning aims to protect biodiversity by sustainng the natural physical, chemical, and biological processes within representative ecosystems. Often data to measure these components are inadequate or unavailable. The impact of human activities on ecosystem processes complicates integrity assessments and might alter ecosystem organization at multiple spatial scales. Freshwater conservation targets, such as populations and communities, are influenced by both intrinsic aquatic properties and the surrounding landscape, and locally collected data might not accurately reflect potential impacts. We suggest that changes in five major biotic drivers—energy sources, physical habitat, flow regime, water quality, and biotic interactions—might be used as surrogates to inform conservation planners of the ecological integrity of freshwater ecosystems. Threats to freshwater systems might be evaluated based on their impact to these drivers to provide an overview of potential risk to conservation targets. We developed a risk-based protocol, the Ecological Risk Index (ERI), to identify watersheds with least/most risk to conservation targets. Our protocol combines risk-based components, specifically the frequency and severity of human-induced stressors, with biotic drivers and mappable land- and water-use data to provide a summary of relative risk to watersheds. We illustrate application of our protocol with a case study of the upper Tennessee River basin, USA. Differences in risk patterns among the major drainages in the basin reflect dominant land uses, such as mining and agriculture. A principal components analysis showed that localized, moderately severe threats accounted for most of the threat composition differences among our watersheds. We also found that the relative importance of threats is sensitive to the spatial grain of the analysis. Our case study demonstrates that the ERI is useful for evaluating the frequency and severity of ecosystemwide risk, which can inform local and regional conservation planning.     

Effects of climate and land use changes on groundwater resources in coastal aquifers

To estimate the freshwater loss in coastal aquifers due to salinisation, a numerical model based on the sharp interface assumption has been introduced. The developed methodology will be useful in areas where limited hydrological data are available. This model will elaborate on the changes in fresh groundwater loss with respect to climate change, land use pattern and hydrologic soil condition. The aridity index has been introduced to represent the variations in precipitation and temperature. The interesting finding is that the deforestation leads to increase groundwater recharge in arid areas, because deforestation leads to reduce evapotranspiration even though it favors runoff. The combined climate and land use scenarios show that when the aridity index is less than 60, the agricultural lands give higher groundwater recharge than other land use patterns for all hydrologic soil conditions. The calculated recharge was then used to estimate the freshwater-saltwater interface and percentage of freshwater loss due to salinity intrusion. We found that in arid areas, the fresh groundwater loss increases as the percentage of forest cover increases. The combined effects of deforestation and aridity index on fresh groundwater loss show that deforestation causes an increase in the recharge and existing fresh groundwater resource in areas having low precipitation and high temperature (arid climates).     

鱼血微核试验在项目竣工环保验收监测中应用

某化工技改项目曾因超标排污引发跨地区厂群纠纷被责令停产整改,为考察该项目整改后废水处理设施的运行效果,在该项目竣工环保验收监测期间,采用鱼外周血红细胞微核试验现场检测废水的遗传毒性。结果表明:Cr6+对鱼外周血红细胞有致突变作用,并有明显剂量效应关系;试验期间废水特征污染物均达标排放,未对生物监测塘中的鲤鱼和鲫鱼产生明显的遗传损伤;微核试验与验收监测结果有可比性。证实了鱼血微核试验可用于长期监控敏感项目废水遗传毒物的排放。