Reference sites

The atomic displacements from reference sites i and j are written as rj and r j. 

Table I indicates the sample size and population estimates of preschoolers by study area and stratum. Though all strata for the Dixie site are shown, at the Dixie site the configuration and location of the major traffic artery in relation to the smelter site did not allow analysis of the contribution of vehicular traffic to soil lead. The contribution of the smelter to soil lead levels was possible at the RSR site and the reference site.

Farallon Islands Nuclear Waste Disposal Site (FINWDS) and Point Arena (reference site), 1986-1987... 

Irish Sea, site impacted by Windscale Reprocessing Plant and reference sites, 1977 EPA 1984... 

PBDEs are a group of chemicals widely used as fire retardants in various commercial products. They have also been found in almost all environmental media around e-waste recycling sites, presumably due to unintended releases during primitive recycling operations. Herein a summary of the levels of PBDEs around e-waste recycling and reference sites is presented. 

Table 1 Concentrations of chlorinated polycyclic aromatic hydrocarbons (CIPAHs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), polybrominated biphenyls (PBBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) in ambient air, soil, and human samples collected from e-waste recycling and reference sites in China... 

In summary, improper e-waste recycling operations are the major contributors of dioxin and dioxin-like compounds to the terrestrial environment in China [7]. The lower concentrations of dioxin and dioxin-like compounds at reference sites than at e-waste recycling sites suggest the likelihood for these chemicals to transport atmospherically from where they are generated to distant areas. We can also infer that dioxin and dioxin-like compounds initially derived from burning of e-waste can enter ambient air and dust and finally deposit into soil. This notion is supported by the significant positive correlation between the levels of PCDD/Fs in dust and soil samples from Taizhou. 

Improper disposal of e-waste has been regarded as the major source of PCDD/ Fs occurring in China s environment [46]. Consequently, e-waste recycling should be somewhat responsible for human exposure to dioxins in China. A comparison of dioxins in human samples from e-waste recycling and reference sites would either confirm or disapprove the notion. The levels of PCDD/Fs (List 4 of Appendix) in human milk samples from a group of pregnant women... 

Table 4 Concentrations of heavy metals in human samples from e-wasting recycling and reference sites in China... 

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...

The effects of Flix sediment pollution on invertebrates were examined at two levels. Local populations of zebra mussels and crayfish (P. clarkii) were sampled right over the Flix residue sediment, across the reservoir, in a meander immediately downstream the dam and in Asco, in addition to the Riba-roja reference site (Fig. 5a, b). Results from a battery of biochemical biomarkers (Fig. 5c) were similar... 

Data from the reference sites to provide class boundary conditions to be established for all groups of water body types. 

Wood duck, Aixsponsa northern Idaho 1986-87 kidneys reference site vs. near mining and smelting complex 0.13 (0.1-1.0) FW vs. 4.8 (1-20) FW 68... 

Deer mice, Peromyscus maniculatus Vancouver Island, British Columbia near abandoned mine vs. reference site 1994... 

INTEGRATED STUDIES England near copper-cadmium refinery vs. reference site ... 

Near leather tannery effluent vs. reference site gills 400-1000 DW vs. Max. 6.0 DW 85... 

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

Central Florida 1991-92 stormwater ponds vs. reference sites whole fish ... 

Liver Rock dove, Columba Hvia Mexico City vs. Ixtlahuaca (reference site) 0.02 FW 52... 

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