Reference sites rivers

In fact, an extensive work on mercury and organomercury levels in zebra mussels collected in several sampling sites in the Flix reservoir area has been reported [32]. The specific sampling points were located in (a) hot spot, (b) wildlife reserve located on the river bank opposite the factory, (c) the meander located immediately downstream from the dam, and (d) a reference site located 1-2 km upstream from the reservoir (Fig. 2). 

The average THg concentration of all tissue samples (n = 285) was 0.2482 0.2546 pg/g, wet weight, ww, ranging from 0.0148 to 0.8052 pg/g. The highest levels were found at the factory site, close to the waste dumping point, followed by the meander, wildlife reserve, and reference sites (Table 1). This fact indicates an important mercury uptake by zebra mussels at the hot spot and redistribution to areas located immediately downstream and near to the river bank opposite the dumping site. 

The choice of reference sites is arguably more difficult that the picking of impacted ones, as human impact is overwhelmingly present all on the Ebro River. For Vero River, the selected reference site was located in a pristine area upstream of Barbastro (see Fig. 1). For Cinca River, the reference site was located upstream of Monzon, avoiding also the influence of the Vero River (see Fig. 1). At the Riba-roja dam (210 Hm3, www.embalses.net), upstream of Flix, Ebro River receives water from several large tributaries. This area was considered as reference for the low Ebro sites. Chemical analyses for different pollutants (see below) of sediments, fish, and shellfish collected in these areas confirmed their suitability as reference sites. 

Fig. 4 Data on pollutant burden and its effects on fish in the low Ebro River, from Riba-roja to Xerta. (a) Total PCB content in sediments from Riba-roja (reference site), Flix, Asco, and Xerta in ng/g (green bars). Superimposed to this profile, line graphs indicate median values for three markers related to...

New Jersey Hackensack River wetlands vs. reference site August-November 1991 ... 

Mayfly, Baetis thermicus whole larvae Japan metal-contaminated river (28.6 pg Cu/L) vs. reference site 73.5 FW vs. 4.0 FW Cu localized in midgut epithelial cells 46... 

Insects immature benthic species whole from copper-contaminated river up to 60 km downstream from outfall (779 mg Cu/kg DW sediments) vs. reference site (18 mg Cu/kg DW sediments)... 

Snapping turtle, Chelydra serpentina-, Big River, Missouri (contaminated with lead mine tailings of 1000-3000 mg Pb/kg tailings) vs. reference site ... 

Coeur d Alene River Basin, Idaho vs. reference site feces Northern Idaho near mining and smelting complex 1987-89 dead or moribund vs. apparently healthy birds from reference site 800 DW (90th percentile was 2700 DW) vs. 2.1 DW 123... 

Haifa Bay, Israel, vs. reference site, 1990 England, marine fishes, near River Tyne, 1992 0.6 FW vs. 0.15 FW 59... 

Canada Wanapitei River (near nickel smelter) vs. Pickerel River (reference site) Ontario 1974 ... 

Niagara River 1991 contaminated sites (Buffalo River, Love Canal) vs. reference site Total PAHs 3.3-5.4 vs. 0.4 26... 

Sediments and biota collected from the Hersey River, Michigan, in 1978, were heavily contaminated with phenanthrene, benz[a]anthracene, and benzo[a]pyrene when compared to a control site. Elevated PAH concentrations were recorded in sediments, whole insect larvae, crayfish muscle, and flesh of lampreys (family Petromyzontidae), brown trout (Salmo trutta), and white suckers (Catostomus commersoni), in that general order (Black et al. 1981). The polluted collection locale was the former site of a creosote wood preservation facility between 1902 and 1949, and, at the time of the study, received Reed City wastewater treatment plant effluent, described as an oily material with a naphthalene-like odor (Black et al. 1981). In San Francisco Bay, elevated PAH concentrations in fish livers reflected elevated sediment PAH concentrations (Stehr et al. 1997). In Chesapeake Bay, spot (Leiostomus xanthurus) collected from a PAH-contaminated tributary (up to 96 mg PAHs/kg DW sediment) had elevated cytochrome P-450 and EROD activity in liver and intestine microsomes (Van Veld et al. 1990). Intestinal P-450 activity was 80 to 100 times higher in fish from highly contaminated sites than in conspecifics from reference sites intestinal EROD activity had a similar trend. Liver P-450 and EROD activity was about 8 times higher in spot from the contaminated sites when compared to the reference sites. Liver P-450 activity correlated positively with sediment PAH, but intestinal P-450 activity seemed to reflect dietary exposure (Van Veld et al. 1990). The poor correlation between hepatic concentrations of PAHs and P-4501A is attributed to the rapid metabolism of these compounds (van der Weiden et al. 1994). 

Kidney Clark Fork River, Montana vs. reference site 11.3 DW vs. 1.8 DW 37... 

Near leather tannery effluent vs. reference site gills Ireland River Calligan 1992-94... 

Idaho Coeur d Alene River 1986-87 Sediments Vicinity of smelter Reference site... 

In order to better understand the wavelengths responsible for PAH phototoxicity from mixtures found in sediments around the Great Lakes, Diamond et al. [183] sampled amphipods (Gammarus spp.) from the Duluth/Superior Harbor, the St. Louis Rivers, which flows into the Harbor, both sites contaminated with point source PAHs and a non-contaminated reference site. These amphipods were exposed to UVA and UVB in separate experiments. The UVA exposed animals showed increased mortality where UVB exposed animals showed no effect. While amphipods are not likely to be exposed to UV in the field, their sensitivity to UV in the laboratory would indicate that organisms that spend part of their life cycle near the sediments and move higher in the water column later might be susceptible to phototoxicity. 

The study of the Kymijoki River has indicated that this river has been contaminated tens of kilometers downstream from the manufacturing site with PCDEs as well as with PCDDs and PCDFs originating as impurities from Ky-5 [114]. The concentrations of PCDEs in reference site sediments upstream from the manufacturing site have been low, as well as those in Baltic sediments [33, 113]. PCDE congeners were below 0.4 ng g 1 dw in sediments from the Gulf of Finland, near Gotland and the Bothnian Bay. 

The SOILPACS study (Weeks et al. 1998). This study investigated the feasibility of the community census approach for soils. The study concluded that a system could be constructed but substantial development was needed. In particular, full faunistic, physical, geological and chemical surveys of many (diverse) reference sites would be needed to develop a system with predictive capability. For development of the UK river invertebrate prediction and classification scheme, over 400 sites were sampled in this manner. The fact that this number would need to be matched for SOILPACS presents a substantial hurdle to development. 

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