Monitoring pollution in River Mureş, Romania, part II: metal accumulation and histopathology in fish

As a part of an exposure and effect monitoring conducted along the river Mureş, Western Romania in 2004, the health status of two indigenous fish species, sneep (Chondrostoma nasus) and European chub (Leuciscus cephalus) was investigated upstream and downstream the city of Arad. In fish, histopathology was assessed in liver and gills, and heavy metals (cadmium, copper, lead and zinc) were analyzed in liver samples. In both fish species, histopathological reactions in the gills (epithelial lifting, focal proliferation of epithelial cells of primary and secondary lamellae and resulting fusion of secondary lamellae, hyperplasia and hypertrophy of mucous cells, focal inflammation and necrosis of epithelial cells) were most severe at the two sampling sites upstream Arad city, which were shown to be polluted by copper, cadmium, faecal coliforms and streptococci in a parallel study. At these two sites, also histopathology in the liver of L. cephalus was more prominent than at the two downstream sites. In C. nasus, symptoms in the liver (focal inflammation with lymphocytic infiltrations, macrophage aggregates and single cell necrosis) were also highly pronounced at the sampling site located directly downstream the municipal sewage treatment plant of Arad. With the exception of copper accumulation in L. cephalus caught at the most upstream sampling site, in both fish species cadmium and copper accumulation were exceptionally high and did not differ significantly between the four sampling sites.     

The study of heavy metal pollution and accumulation in water, sediment, and fish tissue in Kızılırmak River Basin in Turkey

The accumulation of heavy metals such as Pb, Hg, Co, Cr, Cu, Zn, and Br were determined in water, sediment, muscle, and gill of three fish species (Leuciscus cephalus, Capoeta tinca, Capoeta capoeta) which were collected in K?z?l?rmak River Basin (Delice River). The metal concentration showed a general trend of Br>Zn> Pb>Cr>Cu>Hg>Co in water and Cr>Zn>Pb> Cu>Co>Hg>Br in sediment samples while Zn> Cu>Pb>Br>Cr>Hg>Co were in muscle and Zn>Pb>Cu>Cr>Br>Hg>Co were in the gill tissue.     

Risk assessment for methylmercury in fish from the Songhua River,China: 30 years after mercury-containing wastewater outfalls were eliminated

This study aims to investigate the methylmercury contamination of fish from the Songhua River, China. A total of 328 fish representing various trophic levels were captured from ten reaches of the river and determined for methylmercury by gas chromatography method. Total mercury in fish, water and sediments from three typical reaches were analyzed simultaneously. Methylmercury concentrations in fish from the Second Songhua River and the mainstream of the Songhua River were 0.024 ± 0.016 and 0.015 ± 0.007 mg/kg fresh weight, respectively. The proportion of methylmercury to total mercury ranged from 21.8% to 69.7%, with the mean value of 42.6%. The observed methylmercury concentrations were much lower than the historical values and were generally within the reported literature range, and health hazard assessment showed no health risk from exposure to methylmercury by consuming fish from this river, demonstrating that mercury contamination of the Songhua River has been effectively controlled by nearly 30 years of environmental governance and natural purification.     

An Evaluation of Selenium Concentrations in Water, Sediment, Invertebrates, and Fish from the Republican River Basin: 1997–1999

The Republican River Basin of Colorado,Nebraska, and Kansas lies in a valley which contains PierreShale as part of its geological substrata. Selenium is anindigenous constituent in the shale and is readily leached intosurrounding groundwater. The Basin is heavily irrigated throughthe pumping of groundwater, some of which is selenium-contaminated, onto fields in agricultural production. Water,sediment, benthic invertebrates, and/or fish were collected from46 sites in the Basin and were analyzed for selenium to determinethe potential for food-chain bioaccumulation, dietary toxicity,and reproductive effects of selenium in biota. Resultingselenium concentrations were compared to published guidelines orbiological effects thresholds. Water from 38% of the sites (n = 18) contained selenium concentrations exceeding 5 g L^-1, which is reported to be a high hazard for selenium accumulation into the planktonic food chain. An additional 12 sites (26% of the sites) contained selenium in water between 3–5 g L^-1, constituting a moderate hazard. Selenium concentrations in sedimentindicated little to no hazard for selenium accumulation fromsediments into the benthic food chain. Ninety-five percent ofbenthic invertebrates collected exhibited selenium concentrationsexceeding 3 g g^-1, a level reported as potentially lethal to fish and birds that consume them. Seventy-five percent of fish collected in 1997, 90% in 1998, and 64% in 1999 exceeded 4 g g^-1selenium, indicating a high potential for toxicity andreproductive effects. However, examination of weight profilesof various species of collected individual fish suggestedsuccessful recruitment in spite of selenium concentrations thatexceeded published biological effects thresholds for health andreproductive success. This finding suggested that universalapplication of published guidelines for selenium may beinappropriate or at least may need refinement for systems similarto the Republican River Basin. Additional research is needed todetermine the true impact of selenium on fish and wildliferesources in the Basin.     

Relationship Between Micro-Invertebrates and Macrophytes in a Wetland: Laguna Iberá (Corrientes, Argentina). Implications for Water Quality Monitoring

From November 2000 to September 2001, eight points in the Iberá lagoon were sampled bimonthly. At each point, pH, temperature and dissolved oxygen were measured and invertebrates were collected from the water around macrophytes by mean of a net of 180 μ m pore size. Four biotic indices were calculated and compared, given similar trends. The total number of taxa shows to be a good and simple indicator of water quality. Averaging indices across points we obtained a good positive correlation between indices and temperature. In this ecosystem, multi-habitat sampling must be used in order to obtain a good estimation of ecological integrity. The total number of taxa can be used for water quality assessment.     

Determination of pesticide residues in Turkey��s table grapes: the effect of integrated pest management, organic farming, and conventional farming

Turkey is one of the world??s largest producers and exporters of table grapes. Growing social concerns over excessive pesticide use have led to farming to move from conventional to organic practices. Table grapes were collected from 99 different farms in three Aegean regions. Pesticide residues were only detected in farms using conventional agriculture practices while no pesticides were detected in grapes from farms using organic or integrated pest management. A risk assessment model indicated that lambda-cyhalothrin posed the most significant risk at conventional farms.     

Trends of total cadmium, copper, and zinc in the zebra mussel (Dreissena polymorpha) along the upper reach of the St. Lawrence River: 1994—2005

This study examines spatial and temporal variability of bioaccumulation of cadmium, copper, and zinc in tissues of zebra mussels in the upper reach of the St. Lawrence River which originates at the outflow of Lake Ontario. It was hypothesized that concentrations of these metals in mussel tissues would decline over time and decrease with increasing distance from the outlet of Lake Ontario as a result of on-going efforts to reduce contaminant discharges into the lake. Size of mussels was also evaluated as a factor influencing bioaccumulation. Mussels were collected annually in October from six sites from 1994 to 2005, including one site near a local industry. Individuals were grouped into five or more size classes per site in each year. Soft tissues were analyzed for total cadmium, copper and zinc. Concentrations of cadmium and copper in tissues varied significantly both spatially and temporally. Cadmium concentrations were elevated at most sites; copper concentrations were moderately elevated compared with other studies in the Lake Ontario basin and St. Lawrence River. Zinc showed the most uniformity in mussels possibly due to internal regulation and to low levels of environmental exposure. Animal size correlated with copper concentrations of tissues in approximately 30% of samples but infrequently for cadmium and zinc. Cadmium and copper levels were found to decline downstream over time. Inter-annual variability of metal concentrations in mussel tissues suggests utilization in long-term monitoring programs to discern significant trends.     

Pollution caused by peoples�� use for socio-economic purposes (agricultural, recreation and tourism) in the G?lc��k Plain Settlement at Bozda? Plateau (?demi?-?zmir/Turkey): a case study

Mountainous areas, which form the largest geography of our country and are called reserves of resources owing to their difficulty of accessibility, have been increasingly under threat of exploitation and overuse in recent years. The area in question from among the mountainous areas, which are sensitive ecosystems with their environmental components, is the Bozda? mass located in Gölcük Plateau Settlement, which has been subject to intensive construction and use. This study is intended to reveal the current uses of Gölcük Plateau (agricultural, recreation, and tourism) and determine the sources and effects of pollution as a result of these uses and aims at revealing how the permanent residents of Gölcük Plateau Settlement on Bozda? Plateau, which is a center of attraction with respect of recreation and tourism activities, and those who go there only in certain periods, use the environment for tourism and recreational purposes, and determine their positive and negative impacts on environment through SWOT analysis.