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PubMed1980

[Study on the Metagonimus sp. in Gum river basin, Chungchung-nam Do, Korea]

This study was undertaken to elucidate the status of Metagonimus species infection and to demonstrate the first and the second intermediate hosts of the fluke at the several localities along the Gum river, Chungchung-nam Do, Korea from March 1979 to October 1980. The results are summarized as follows: 1. Total 790 stool specimens of inhabitants from 6 localities along Gum river were examined by the combination of cellophane thick smear technique and formalin-ether concentration technique. The positive rate of intestinal helminths was 80.3 %, and the egg positive rate of Metagonimus sp. was 21 % from a total of 790 specimens examined. In the age bracket of 20~49, the positive rates of Metagonimus sp. were 31.1~36.5 %, and the males (26.8 %) were infected three times higher than females (8.9 %). By the area of the river, Gumsan which is located upper stream showed the highest positive rate (40.5 %) of the fluke, whereas the rates decreased gradually toward upper part of river (Muju) or the descending lower area of the river. The most lower area of river (Gangkyeong and Nonsan), no positive Metagonimus infection case was found. 2. The infection rate of Clonorchis sinensis in 790 was 37.3 %, and the status of mixed infection of Metagonimus with C. sinensis was found 127 cases (76 %) out of 166 cases with Metagonimus infection. 3. The result of measurement of ova from 166 cases of Metagonimus infection, large ova were found in 41.1 %, small size ova in 31.9 % and the mixed type in 27.1 %, respectively. The adult worms were recovered from the 6 cases after treatment with niclosamide, and the measurements of the worms showed similar morphological characteristics of the Metagonimus yokogawai. 5. Twenty-two species in 5 families of fresh water fish were caught. Out of 22 species of fish, 18 species were found infected with metacercaria of Metagonimus. In order to observe the distribution of metacercariae in the body and the rate of infection of the individual host, a total of 94 Pseudogobio esocinus were examined. Total 84 (89.4 %) out of 94 fish were infected with the metacercariae and the rates of distribution of the metacercaria were observed in the following order: on scale; 93.4 %, in gill; 3.2 %, head part; 2.9 %, but a few metacercaria was found in muscle and visceral organs. 6. The development of the metacercariae which were isolated from the scale of Pseudogobio esocinus were experimentally traced in the albino rat host from one day to 30 days after infection. At the 6th day, several eggs were visible in the uterine tubule of the some worms, on the 10th day, worms became 326.0 x 208.0 micrometer in size, however the bodies of worms grew no more until the 30th day after infection. The oral sucker was larger in size than the ventral sucker during early stage of the worms, but the 7th day after infection, it reversed. The ventral sucker situated on the ventral right side of the body. Right side of testis laid somewhat toward, and uterus and vetellaria extended to the posterior margin of the right testis. 7. Snails(Koreanomelania nodifila var. ovulum) were collected in the river, Buri-Myeon, Gumsan-Gun, and found the natural emerging ophthalmo-pleurophocercus cercaria. From the above result, the prevalence of Metagonimus species infection showed relatively higher rates from the inhabitants along the middle to upper localities of the river. Even though no sweetfish was caught in the surveyed areas, Gum river basin is the one of the new endemic foci of metagonimiasis in Korea.

Journal Article↗
PubMed1999

Seasonal variations in water quality of an oxbow lake in response to multiple short-time pulses of flooding (Jataí Ecological Station--Mogi-Guaçu River, Luiz Antonio, SP-Brazil).

Mogi-Guaçu River is a six-order floodplain river in the upper Paraná River Basin, Southern Brazil. Its yearly discharge varies from a minimum of 100 m3.s-1 to a maximum of 600 m3.s-1. Diogo Lake is a shallow lake located at its floodplain within the Jataí Ecological Station (Luiz Antonio, São Paulo State) and is connected throughout the year to the river through a narrow and shallow channel. The main finding of this study is that the river hidrology controls the annual variations in lake hydrochemistry through a series of hydraulic effects related to oscillations in river discharge. Lake water quality is a resultant of differential contribution from local and regional watersheds. During the low water period, lake water quality is determined by inputs from Cafundó Creek, which drains the local watershed into the lake. Raising the river level during the rain season results in the damming of lake and culminates with the entrance of river waters into the plain. The geochemistry of waters in this system is determined by weathering of sandstones with basalt intrusions. Waters are acidic (river pH = 6.00 to 7.02 and stream-lake pH = 5.15 to 6.7) and dominant cations are Na+ and K+. Major anions are almost exclusively represented by bicarbonate and an unknown concentration of organic acid anions. The overall ionic load of these soft waters in the system is therefore very low.

Brazil↗
PubMed2001

An evaluation of the etiology of reduced CYP1A1 messenger RNA expression in the Atlantic tomcod from the Hudson River, New York, USA, using reverse transcriptase polymerase chain reaction analysis.

Adult Atlantic tomcod, Microgadus tomcod, from the Hudson River, New York State, USA, exhibit reduced inducibility of hepatic cytochrome P4501A1 (CYP1A1) mRNA compared with adult tomcod from the cleaner Miramichi River, New Brunswick, Canada, when treated with coplanar polychlorinated biphenyl (PCB) congeners or 2,3,7,8-tetrachlorodibenzo-p-dioxin. In contrast, little difference in CYP1A1 inducibility is observed between tomcod from these two rivers when treated with polycyclic aromatic hydrocarbons (PAHs). We sought to determine if impaired hepatic CYP1A1 inducibility in Hudson River tomcod results from a multigenerational, genetic adaptation or a single generational, physiological acclimation. Embryos and larvae from controlled experimental crosses of Hudson River and Miramichi River parents were exposed for 24 h to water-borne PCB congener 77 (10 ppm), benzo[a]pyrene (BaP; 10 ppm), or dimethysulfoxide, and CYP1A1 expression was assessed in individual larva using competitive reverse transcriptase polymerase chain reaction (RT-PCR) analysis. The CYP1A1 mRNA was significantly induced in larvae from both populations by BaP (47- and 52-fold) and PCB 77 (9- and 22-fold), although levels of expression were higher in offspring of Miramichi matings. Most important, CYP1A1 mRNA was significantly induced by PCB 77 in larvae from Hudson River parents. Concentrations of dioxin, furan, and PCB congeners were measured in livers and eggs of female tomcod from these two locales to quantify the extent of maternal transfer of contaminants. For both rivers, wet-weight contaminant concentrations were significantly higher (4-7 times) in livers than in eggs of the same females, suggesting that a threshold level of contaminants may have to be reached before CYP1A1 transcription is impaired. We conclude that reduced inducibility of hepatic CYP1A1 mRNA in adult tomcod from the Hudson River is most consistent with single-generational acclimation.

Animals↗
PubMed2001

Classifying urban rivers.

Classification systems have been developed over the last century as a tool to aid managers in the preservation, conservation, enhancement and management of rivers. The classification systems developed to date have been designed to differentiate between relatively unimpacted, mainly rural rivers. Urban rivers typically show poor water quality and biological diversity, and so most current classification systems tend to group urban rivers into a single "poor" category. In this paper we describe a hierarchical framework for recording information about urban rivers that allows a more sensitive description of these rivers enabling subdivision into several classes according to the purpose of the classification. The different levels in the hierarchy, the types of attributes that are to be recorded at each level, and the relational database structure for storing the data are described. The 100-500 m river stretch level in the hierarchy relates to the engineered modification of urban rivers and is the key to their classification. An example classification at this scale illustrates a link between engineering modification, bank and bed materials and the number and diversity of physical habitats present. This classification underlines the importance of adopting a hierarchy of nested spatial scales for data collection, classification and interpretation since it illustrates a clear link between characteristics at the stretch scale and at the finer habitat scale. The classification also illustrates the varied nature of urban rivers and the fact that even quite heavily engineered stretches can contain a diversity of habitat types.

Cities↗
PubMed1997

Intestinal helminths of river otters (Lutra canadensis) from the Pacific northwest.

The intestinal helminth fauna of river otters, Lutra canadensis, from the Pacific Northwest was characterized by low species richness and intensity of infection. River otters from the lower Columbia River (n = 23) were infected with 9 species of helminths (83% prevalence); those from a relatively undisturbed reference area near the headwaters of the Trask and Wilson rivers on the Oregon coast (n = 6) were infected by 5 species of helminths (100% prevalence). Single species of Eucestoda (Schistocephalus solidus), Digenea (Euparyphium inerme), Acanthocephala (Corynosoma strumosum), and 8 species of Nematoda (Strongyloides lutrae; larvae of Eustrongylides sp., Anisakis sp., and Contracaecum sp.; 3 of Cystidicolidae, and Hedruris sp.) were collected. Most species are typical of piscine definitive hosts and were present as incidental parasites of river otters. Notably, specimens of Euparyphium inerme are reported for the first time in river otters from North America; occurrence of other helminths constitutes new host or geographic records for parasites in river otters in Oregon and Washington. Parasites with marine life cycles were acquired by river otters in freshwater habitats at a great distance from the ocean. The helminth fauna of river otters in the Pacific Northwest was influenced primarily by ecological factors and was indicative of eclectic food habits and the relatively extensive home ranges occupied by these mustelids.

Acanthocephala↗
PubMed2004

Assessing the restoration success of river widenings: a landscape approach.

During the last 200 years, many rivers in industrialized countries have been modified by canalization. In the last two decades, the philosophy of river management has changed considerably, and restoration of ecological integrity has become an important management goal. One appealing restoration approach is to create "river widenings" that permit braiding within a limited area. This study presents a new and efficient framework for rapidly assessing such widening projects and offers a novel method to comparing restored sites with near-natural stretches (stencil technique). The proposed framework evaluates spatial patterns of riparian habitat types using landscape metrics as indicators. Three case studies from river restoration (river widening) in Switzerland are presented for demonstration purposes. The method compares restored sites with prerestoration conditions and near-natural conditions, which are assumed to represent the worst and best case states of a river system. To take into account the limited spatial extent of the restored sites, the so-called "stencil technique" was developed, where the landscape metrics of the near-natural reference sites are calculated for both the entire study area and smaller sections (clips). The clips are created by using a stencil that has the exact shape and size of the restored area (random window-sampling technique). Subsequently, the calculated metrics for the restored sites are compared to the range of values calculated for the near-natural data subset. Our studies show that the proposed method is easy to apply and provides a valid way to assess the restoration success of river widenings. We found that river widenings offer real opportunities for establishing riparian habitats. However, they promote mainly pioneer successional stages and the habitat mosaic of the restored section is more complex than at the near-natural reference sites.

Conservation of Natural Resources↗
PubMed2005

Contamination of oxygen-consuming organics in the Yellow River of China.

Contamination of oxygen-consuming organics (OCOs) was one of the most serious problems in the Yellow River of China. This study was conducted to analyze monitoring of the data on OCOs contamination for the river in 1980 and during 1992-1999 as well as examining the effect of suspended solids (SS) on chemical oxygen demand (CODMn) and biochemical oxygen demand (BOD5) of river water. Several significant results have arisen from the study. First, CODMn and BOD5 of the river water showed an increasing trend from the upper to the lower reaches of the mainstream. BOD5 values of river water in 1992 were significantly higher than those in 1980 and showed an increasing trend during 1992-1999. Second, OCOs in river water of the mainstream was attributed mainly to point sources; the ratio of point to non-point sources of BOD5 was about 2.81. The load from point sources showed an increasing trend during 1992-1998. In contrast, the load from non-point sources manifested a decreasing trend during this period; this was caused by the decreasing trend of SS content in river water. The total load of BOD5 from point and non-point sources displayed an increasing trend during 1992-1998. Third, as the humic substances in SS can hardly be biologically oxidized in natural conditions but can be oxidized by chemical oxidants such as potassium permanganate, CODMn was not suitable for being regarded as a parameter reflecting the pollution degree of OCOs in river water with a high SS content.

Benzopyrans↗
PubMed2006

Heavy metal transport in the hindon river basin, India.

Total mass transfers of heavy metal in dissolved and particulate form has been determined in the downstream section of river Hindon, an important tributary of river Yamuna (India). The contribution of different point sources to the river Hindon has also been assessed. The river Kali has the largest contribution to the river Hindon. The highest metal loads were related to the highest flow of the river and thereby increased both by surface runoff and sediment resuspension. The contribution of monsoon months to the total transported load was also calculated and it was observed that monsoon months contributes more than 40% of total loading annually for all the metals. The metal fluxes from the river Hindon were compared with other rivers of Indian sub-continent.

Environmental Monitoring↗
PubMed2006

Temporal and spatial variation of nutrient levels in the Nemunas River (Lithuania and Belarus).

There are discordant results on trends in nutrient river water quality from the economical transition countries in Europe. The present study assessed the impact of these economical changes on the load and concentration at 17 monitoring stations along the Nemunas River and its major tributaries (Lithuania and Belarus). Three time periods were evaluated: the Soviet rule command system period 1986-1991, the transfer to market economy period 1992-1996 and the post reform period 1997-2002. The most surprising result in this study, was the increased area-specific load of NO(3)-N from the first to the third period at almost all the sampling sites. The increase was particularly large (43-78%) at the sites in the Lithuanian part of the river. The corresponding load increase in the Belarussian part of the river was only 1-15%. The statistical analyses of concentration data confirm the strong upward NO(3)-N trend at the Nemunas mouth and at 5 of the 6 tributaries in the lower part of Nemunas. Temporal and spatial analysis of nitrates transport in the Nemunas River and its main tributaries revealed that nitrates mainly originate from agricultural areas. The upward trends were most likely an effect of ploughing of pastures and unbalanced crop fertilisation in combination with large storage and accumulation of soil-nitrogen during the Soviet period. On contrary to nitrate-N, the area-specific load of PO(4)-P decreased significantly from the first to the third period at all sites along the Nemunas River (31-86%). Seasonal (SMK) and Partial (PMK) Mann-Kendall tests on PO(4)-P concentrations also showed significant downward trend at 14 of 16 investigated sites. The decrease of PO(4)-P levels was attributed to the reduction of municipal and industrial point source emissions and to the decreased livestock numbers. The NH(4)-N load showed the same pattern as PO(4)-P. At the river mouth the load was 90 kg km(-2) yr(-1) during the first period compared to only 20-30 kg km(-2) yr(-1) in the third period. The trend test on NH(4)-N concentrations detected significant downward trends at 5 out of 16 sites. The declines were explained by decreased emissions from cities and large animal breeding farms. This study showed that trend analysis at multiple sites in a river basin is crucial for the understanding of the variability in time and space. Such analysis is also important for our interpretation of underlying sources and fluxes in a drainage basin over time. This is particularly important for compounds that have different source origin.

Environmental Monitoring↗
PubMed2006

Influence of mining activities in the North of Potosi, Bolivia on the water quality of the Chayanta River, and its consequences.

Mining activity in the North of Potosi (Siglo XX mine, Ingenio Catavi-Siglo XX, Pucro mine and Colquechaca mine) produces minewater containing high concentrations of heavy metals such as As (0.02-34 mg/l), Cd (45-11,600 microg/l), Cu (0.35-32 mg/l), Fe (42-1,010 mg/l), Pb(33-3,130 microg/l), Ni(20-4,320 microg/l), and Zn (1.1-485 mg/l), that exceed considerably the limit values. The rivers in the North of Potosi (Katiri and Pongoma) that do not receive minewater contain clear water with rather low heavy metal concentrations. These rivers and also other rivers contaminated with minewater, are tributaries of the Chayanta River that transports water with a high concentration of heavy metals such as As (6-24 microg/l), Cd (260-2,620 microg/l), Cu (205-812 microg/l), Pb(10-21 microg/l) and Ni(110-332 microg/l). These elements result from mining activity, as indicated by a comparison with rivers not contaminated by minewater discharges. Water of the Chayanta River, used all year long by the population of Quila Quila, (a village situated at about 75 km from the mining centers), for the irrigation of crops such as potato, maize and broad bean, contains heavy metal concentrations exceeding for several elements the guidelines for irrigation. As drinking water the population of Quila Quila consumes spring water with a generally acceptable heavy metal concentration, as well as infiltrated water of Chayanta River (which is also used in animal drinking troughs) with a high concentration of Cd (23-63 microg/l), exceeding the limit value for drinking water. The metal concentration is significantly lower in the infiltrated water than in the water of Chayanta River. Some technological solutions are suggested to improve the quality of the water used. Surveys carried out on inhabitants of the region, showed that many people present health problems, probably to be attributed to the bad quality of the water they consume and use for irrigation.

Bolivia↗
PubMed2006

Abiotic ecotypes in south-central Spanish rivers: reference conditions and pollution.

Physico-chemical water quality in five of Spain's main rivers was assessed during the years 2001-2003. A previous physiographical river typology was carried out by applying System B of the Water Framework Directive (2000/60/CE) which distinguished four main river ecotypes: calcareous headwaters, siliceous rivers, plain rivers, and large rivers. The physiographical classification into river ecotypes also corresponded to distinct hydrochemical types. Reference values of ammonium, nitrate and phosphate fitted for local river ecotypes surpassed only slightly the natural and background levels established by the European Environmental Agency (EEA, 2003). Half of the sampled sites were above the limits established as reference conditions. Additionally, concentrations of ammonium, nitrite, nitrate, and phosphate increased when more percentage of land was dedicated to agriculture and less to forest land.

Animals↗
PubMed2005

A river water quality model integrated with a web-based geographic information system.

Scientists often use mathematical models to assess river water quality. However, the application of the models in environmental management and risk assessment is quite limited because of the difficulty of preparing input data and interpreting model output. This paper presents a study that links ArcIMS, a Web-based Geographic Information System (GIS) software to ROUT, a national and regional scale river model which evolved from the US Environmental Protection Agency's Water Use Improvement and Impairment Model, to create a WWW-GIS-based river simulation model called GIS-ROUT. GIS-ROUT is used to predict chemical concentrations in perennially flowing rivers throughout the continental United States that receive discharges from more than 10,000 publicly owned wastewater treatment plants (WWTPs). The WWTP chemical loadings are calculated from per capita per day disposal of product ingredients and the population served by each plant. Each WWTP, containing data on treatment type and influent and effluent flows, is spatially associated with a specific receiving river segment. Based on user defined treatment-type removal rates for a particular chemical, an effluent concentration for each WWTP is calculated and used as input to the river model. Over 360,000 km of rivers are modeled, incorporating dilution and first order loss of the chemical in each river segment. The integration of spatial data, GIS, the WWW, and modeling in GIS-ROUT makes it possible to organize and analyze data spatially, and view results on interactive maps as well as tables and distribution charts. The integration allows scientists and managers in different locations to coordinate and share their estimations for environmental exposure and risk assessments.

Geographic Information Systems↗
PubMed2004

Plutonium isotopes in the lower reaches of the River Rhône over the period 1945-2000: fluxes towards the Mediterranean Sea and sedimentary inventories.

Plutonium isotopes in the Rhône River originate from both the weathering of the catchment basin contaminated by global atmospheric fallout, and the liquid effluents released from the Marcoule reprocessing plant since 1961. Due to a new treatment process applied to the liquid effluents, a decrease of two orders of magnitude in the industrial plutonium discharged into the River Rhône has been registered from 1991. Today, 238Pu industrial inputs to the River Rhône are still about 10 times higher than those derived from global fallout, while 239+240Pu inputs from industrial and global fallout sources are of similar importance, i.e. 1 GBq y(-1). Our results indicate that the river sedimentary compartment act either as a sink or a delayed-source term of plutonium for the freshwaters depending on the hydraulic regime and flood events. This compartment may then represent an important industrial delayed-source term for the River Rhône freshwaters in the coming years as the Marcoule reprocessing plant is being dismantled. These results were obtained from samples collected from the lower course of the River Rhône over the 1987-1998 period and analysed for 238Pu and 239+240Pu activities. Both river sedimentary inventories of plutonium isotopes and effective outputs from the River Rhône towards the Gulf of Lions have been estimated for each year over the 1945-2000 period. Regarding 239+240Pu, the sedimentary inventory accumulated since 1945 is estimated to be 172+/-35 GBq. If mobile, this amount represents a significant delayed-source term of plutonium on the scale of the Rhône watershed.

Disasters↗
PubMed2004

Seasonal and annual loads of hydrophobic organic contaminants from the Susquehanna River basin to the Chesapeake Bay.

Water from the Susquehanna River was collected and analyzed for polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyl (PCB) congeners to estimate seasonal and annual riverine loads to the Chesapeake Bay. Temporal variations in the chemical loads resulted from the large changes in the water flow rates and in the particle-associated contaminant concentrations. Concentrations of PCBs and PAHs in river particles (ng/g) were twice as great as those in the northern Chesapeake Bay, indicating that the Susquehanna River is an important source of these contaminants to the bay. The river carries a majority of its hydrophobic organic contaminants (HOCs) in the particulate phase. During periods of high flow, large amounts of suspended particles in the river result in elevated HOC levels and increased loadings of these contaminants to the bay. From 1997 to 1998, 60% of the total annual HOC loading occurred in the early spring coincident with high river flows. The total PCB and PAH annual loadings from the Susquehanna River to the Chesapeake Bay were 76 and 3160 kg/year, respectively and 75% of the loaded organic contaminants were in the particulate phase. Principal component analysis of PAH and PCB congener patterns in the particles reveals that the river suspended particles were dominated by autochthonous production in the summer and by resuspended sediment and watershed erosion during the winter and early spring.

Chromatography, Gas↗
PubMed2004

A retrospective analysis of trace metals, C, N and diatom remnants in sediments from the Mississippi River delta shelf.

The development of oil and gas recovery offshore of the Mississippi River delta began in shallow water in the 1950s, expanded into deeper waters, and peaked in the 1990s. This area of the outer continental shelf (OCS) is the historical and present location of >90% of all US OCS oil and gas production and reserves. The juxtaposition of its 4000 producing platforms, recovering $10 billion yr(-1) of oil, gas and produced water in the same area where about 28% of the US fisheries catch (by weight) is made and near 40% of the US coastal wetlands, makes this an area worth monitoring for regional pollutant loading. This loading may come from several sources, including sources related to OCS development, but also from the Mississippi River watershed. In this context, any contaminant loading on this shelf may be neither detectable nor significant against a background of climatic or biological variability. We examined the sedimentary record for indicators of industrial byproducts from OCS oil and gas development and of industrial products entering via the Mississippi River, primarily using vanadium (V) and barium (Ba) concentrations normalized for aluminum (Al). Barium is primarily used in drilling muds in the form of barite, whereas V is an important strengthening component of metal alloys, including steel. The fluctuations in the accumulation of Ba, but not V, were coincidental with the presumed use of barite. The fluctuations in V concentration in the sediments were coincidental with the national consumption of V. Copper (Cu), cadmium (Cd) and zinc (Zn) concentrations in sediments fluctuate coincidentally with V, not Ba, thus indicating that the dominant source of these trace metals in offshore sediments were derived from riverine sources, and were not primarily from in situ industrial processes releasing them on the shelf. This is not to suggest that local site-specific contamination is not a significant management or health concern. The low oxygen (hypoxia; < or = 2 mg l(-1)) zone that consistently covers much of this continental shelf's bottom layer in summer is attributed to nitrate loading from the Mississippi River. Increased nitrogen loading from river to shelf stimulates diatom production whose loading to the bottom layer and subsequent metabolism results in oxygen being depleted faster than it is replaced. In the last two decades there has been an increased accumulation of organic matter in sediments near the mouth of the Mississippi River. This coupling between river water, surface water and bottom water has recently expanded westward of the Atchafalaya River delta towards the Texas coast. The accumulation of biogenic silica (BSi) and carbon in dated sediments is coincidental with variations in riverine nitrate flux, but not with either V or Ba accumulation rates. These analyses indicate that both OCS development and riverine sources exert strong influences on the sediment constituents offshore, and that these influences may be independent of one another.

Carbon↗
PubMed2005

Sulfur and strontium isotope geochemistry of tributary rivers of Lake Biwa: implications for human impact on the decadal change of lake water quality.

To study the deterioration of the water quality in Lake Biwa, Japan, over the last 40 years, we measured the concentrations and isotopic ratios of sulfur and strontium of water in 41 inflowing rivers and one discharging river. The concentrations of SO4 and Sr of inflowing rivers at downstream sites were generally high in the southern urban area and in the eastern area, where a large agricultural plain is situated, but low in the northern and western areas, whose watersheds are mountainous and with low population density. SO4 and Sr concentrations are also lower at upstream sites, which are closer to mountainous areas. Thus, the inflowing river receives large amounts of SO4 and Sr as it flows across the plain, where human activity levels are high. The delta34S or 87Sr/86Sr values of most eastern rivers at downstream sites are lower than those of water in Lake Biwa, and values become more uniform as the proportion of the plain area in the watershed increases. River water in other areas has higher values of delta34S or 87Sr/86Sr than the lake water. This result indicates that the decadal decrease of delta34S and 87Sr/86Sr in the lake water has been caused mainly by the increased flux of SO4 and Sr from rivers in the eastern plain. We assume that in the plain, sulfur, nitrogen, and organic compounds induced by human activities generate sulfuric, nitric, and organic acids in the water, which accelerate the extraction of Sr from bedrocks, leading to the generation of Sr in the river water in the area.

Environmental Monitoring↗
PubMed2004

Impacts of a heavy storm of rain upon dissolved and particulate organic C, N and P in the main river of a vegetation-rich basin area in Japan.

The impacts of a heavy storm of rain upon the dissolved and particulate organic matter (OM), nitrogen (N) and phosphorus (P) in the main river of the vegetation-rich Nagara River basin were investigated using water samples collected along the river line during a critical typhoon-induced heavy rain storm event. Besides, based on a high performance size-exclusion chromatography (HPSEC) system, the variance of dissolved OM (DOM) in its molecular weight (MW) characteristics was also assessed. From the MW standpoint, DOM components merged into the river along the river line resembled those present in its headwater. The MW range changed only slightly from 1010 to 5900 at the upstream (US), to 1130-5900 and 1200-5900 Da at the midstream (MS) and downstream (DS), respectively, while the corresponding weight-averaged MW (M(w)) decreased from 3669 to 3330 and 2962 Da. The heavy storm of rain enhanced the content of DOM; however, apart from a small larger-MW fraction (about 5900-6800 Da), the newly emerged DOM constituents exhibited an MW range similar to those existed before the storm. Due also to the storm of rain, total P and N (TP and TN) changed markedly in the ranges of 6.6-11.9, 8.3-40.6 and 48.4-231.3 microg/l for TP, and 145.4-296.0, 502.2-1168.7 and 1342.7-1927.3 microg/l for TN at the US, MS and DS, respectively. The larger values of TP and TN generally appeared for samples at elevated river water levels. The enhanced presence of P was found largely attributed to its particulate form; while, for N, the contribution from its dissolved form was significant. The newly emerged suspended particles via the storm-water contained lower content of OM, N and P, and a general decreasing trend of the particulate OM, N and P along the river line was also confirmed. The C/N ratio in the dissolved form varied in 0.7-6.7 and decreased downstream, while, that in the particulate form 2.3-17.3. Suspended particles that emerged in the river water during the storm exhibited larger C/N values. N/P in both dissolved and particulate forms varied in the ranges of 2.2-17.1 and 12.9-444.9, respectively, and a general trend of either increasing or decreasing in relation to the storm of rain was not revealed.

Agriculture↗
PubMed2005

Anthropogenic impacts on mercury concentrations and nitrogen and carbon isotope ratios in fish muscle tissue of the Truckee River watershed, Nevada, USA.

The lower Truckee River originates at Lake Tahoe, California/Nevada (NV), USA and ends in the terminal water body, Pyramid Lake, NV. The river has minimal anthropogenic inputs of contaminants until it encounters the cities of Reno and Sparks, NV, and receives inflows from Steamboat Creek (SBC). SBC originates at Washoe Lake, NV, where there were approximately six mills that used mercury for gold and silver amalgamation in the late 1800s. Since then, mercury has been distributed down the creek to the Truckee River. In addition, SBC receives agricultural and urban nonpoint source pollution, and treated effluent from the Reno-Sparks water reclamation facility. Fish muscle tissue was collected from different species in SBC and the Truckee River and analyzed for mercury and stable isotopes. Nitrogen (delta(15)N) and carbon (delta(13)C) isotopic values in these tissues provide insight as to fish food resources and help to explain their relative Hg concentrations. Mercury concentrations, and delta(15)N and delta(13)C values in fish muscle from the Truckee River, collected below the SBC confluence, were significantly different than that found in fish collected upstream. Mercury concentrations in fish tissue collected below the confluence for all but three fish sampled were significantly greater (0.1 to 0.65 microg/g wet wt.) than that measured in the tissue collected above the confluence (0.02 to 0.1 microg/g). Delta(15)N and delta(13)C isotopic values of fish muscle collected from the river below the confluence were higher and lower, respectively, than that measured in fish collected up river, most likely reflecting wastewater inputs. The impact of SBC inputs on muscle tissue isotope values declined down river whereas the impact due to Hg inputs showed the opposite trend.

Animals↗