Aquatic Oligochaeta (Annelida) of Dam Lakes Çatören and Kunduzlar (Turkey)

Çatören and Kunduzlar Dam Lakes, located on Seydi River, represent the main irrigation water resources of the Seyitgazi District (Eskişehir Province), in west-central Turkey. The river and the reservoirs are both under the threat of pollution primarily originating from several domestic point source discharges and land-based runoff. The numerical and proportional distributions of oligochaetes in Çatören and Kunduzlar Dam Lakes were surveyed seasonally in 2010 and 2011 at two stations on each lake. According to the results of this study, the benthic invertebrate fauna of Çatören Dam Lake consisted of Oligochaeta (40.2 %), Chironomidae larvae (32.2 %) and the varia (27.6 %); the benthic invertebrate fauna of Kunduzlar Dam Lake consisted of Oligochaeta (56.7 %), Chironomidae larvae (18.2 %) and the varia (25.1%). By evaluating the data via a Shannon-Wiener index it was found that the Çatören Dam Lake had an index of 2.32; while Kunduzlar Dam Lake had an index of 3.27. Several physicochemical water quality parameters were also analyzed during this study. The relationships between the dynamics of organisms and environmental parameters were supported by Pearson correlation index. It was determined that Çatören and Kunduzlar Dam Lakes waters were polluted and slightly polluted, respectively. The dominance and abundance of oligochaete species and low species richness showed that similar studies should be carried out periodically in Çatören and Kunduzlar Dam Lakes for the future monitoring of the dam lakes.

Diastereoisomer- and enantiomer-specific profiles of hexabromocyclododecane in the sediment of Dongjiang River, South China

Environmental contextHexabromocyclododecanes are widely used as additive brominated flame retardants in thermal insulation building materials, upholstery textiles and electronic products. Dongjiang River is located at the Pearl River Delta, one of the most highly industrialised regions in China, which was seriously polluted by hexabromocyclododecanes. Higher levels of hexabromocyclododecanes in Dongjiang River will pose a serious threat to ecological health in this region. AbstractThe objective of this study was to investigate the levels, diastereoisomer profiles and enantiomeric fractions of hexabromocyclododecanes (HBCDs) in the sediment of the Dongjiang River, China. The results showed that the total HBCD concentrations in the sediment ranged from below 2.5 to 424.16 ng g–1, which is similar to levels downstream of point source discharges in Europe and significantly higher than HBCD levels in sediments from rivers in the USA. The diastereoisomeric pattern showed the predominance of the γ-isomer, with low contributions of the α- and β-isomers. This diastereoisomer profile of the HBCDs was similar to that of commercial formulations. No uniform enantioselective enrichment was observed for α- and β-HBCD in sediments, which suggested that different stereoselective biotransformations occurred for these two isomers at different sites. However, (–)-γ-HBCD was apparently enriched in the sediment, which suggested that HBCDs in these studied sites were selectively biodegraded by microorganisms in the sediment.

Predicting potential change in agricultural sediment inputs to rivers across England and Wales by 2015

Recent work has evaluated the gap between current and compliant suspended sediment losses due to farming across England and Wales and the potential for change by 2015. The study adopted the guideline annual average sediment threshold of 25 mg L–1 cited by the European Union Freshwater Fish Directive. Compliance testing required national scale sediment source apportionment to assess the current contributions of diffuse agricultural and urban sector losses, channel bank erosion and point source discharges to the total suspended sediment loads delivered to all rivers. Results suggested that the agricultural sector dominates present day (year 2000) sediment inputs to rivers (1929 kt = 76%) compared with eroding channel banks (394 kt = 15%), diffuse urban sources (147 kt = 6%) and point source discharges (76 kt = 3%). Projected change in farming by 2015, represented by the Business As Usual forecast of structural developments and predicted uptake of sediment mitigation methods, suggested a 9% reduction in sediment losses from the agricultural sector across England and Wales. Further mitigation of diffuse agricultural sediment transfers to watercourses will therefore be necessary to ensure ‘good ecological status’ in some catchments. A similar modelling framework could be applied in other countries.

Changes of the nutrient loads of the Odra River during the last century - their causes and consequences

Changes of the nutrient loads of the Odra River during the last century - their causes and consequencesNutrient emissions by point and diffuse sources and their loads were estimated for the Odra catchment over the time period of the last 50 years by means of the model MONERIS. For nitrogen a change of the total emissions from 38 kt·a−1N in the mid of 1950s a maximum of 105 kt·a−1N in the early 1980s and a recent value of about 84 kt·a−1N were estimated for the total Odra Basin. The share of the point source discharges on the total N emissions varied between 24% (1955) and 35% (1995). The emissions from groundwater and tile drained areas represent the dominant pathway (37-56% of total N emissions) during all investigated time periods. Emissions from tile drained areas increased from the mid of 1950s to end of 1980s by a factor of 20 and reached in this period the same amount as emissions by groundwater. For phosphorus the emissions changed from 4 kt·a−1P in 1955 to 14 kt·a−1P in 1990 and a recent level of 7 kt·a−1P. Point source discharges caused between 36 to 66% of total P emissions and represent the dominant pathway for all investigated time periods. Erosion and discharges from paved urban areas and sewer systems was the dominant diffuse pathway of the total P emissions into the river system. The comparison of calculated and observed nutrient loads for the main monitoring stations along the Odra River shows that the average deviation is 12% for total phosphorus (1980-2000) and 15% for dissolved inorganic nitrogen (1960-2000). From the analysis it can be concluded that the present load of dissolved inorganic nitrogen (DIN) and total nitrogen (TN) of the Odra into the Baltic Sea is about 2.3 times higher than in the mid of 1960s. The maximum DIN load (1980s) was more than 3 times higher than in the 1960s. The change of the total phosphorus (TP) load is characterized by an increase from the 1955s to 1980 from 2 to 7 kt·a−1P (factor 2.6). Around 2000 the TP load was 4 kt·a−1which is only the double of the level of the 1955s.

Landscape Influences on Stream Habitats and Biological Assemblages

<em>Abstract.</em>—We used data sets of differing geographic extents and sampling intensities to examine how data structure affects the outcome of biological assessment. An intensive sampling (<em>n </em>= 97) of the Muskegon River basin provided our example of fine scale data, while two regional and statewide data sets (<em>n </em>= 276, 310) represented data sets of coarser geographic scales. We constructed significant multiple linear regression models (<EM>R</EM>² from 21% to 79%) to predict expected fish assemblage metrics (total fish, game fish, intolerant fish, and benthic fish species richness) and to regionally normalize Muskegon basin samples. We then examined the sensitivity of assessments based on each of five data sets with differing geographic extents to landscape stressors (urban and agricultural land use, dam density, and point source discharges). Assessment scores generated from the different data extents were significantly correlated and suggested that the Muskegon basin was generally in good condition. However, using coarser scale data extents to determine reference conditions resulted in greater sensitivity to land-use stressors (urban and agricultural land use). This was due in part to significant covariance between land use and drainage area in the fine scale data set. Our results show that the scale of data used to determine reference condition can significantly influence the results of a biological assessment. The training data sets with broader spatial range appeared to produce the most sensitive and accurate catchment assessment. A covariance structure analysis using a data set with broad spatial range suggested that impounded channels and point source discharges have the strongest negative effects on intolerant fish richness in the Muskegon River basin, which provides a focus for conservation, mitigation, and rehabilitation opportunities.