Efficiency of sediment quality guidelines for predicting toxicity: the case of the St. Lawrence River.

Cemagref UR MALY, 3bis quai Chauveau CP 220, 69336 Lyon Cedex 9, France.
Integrated Environmental Assessment and Management 04/2010; 6(2):225-39. DOI: 10.1897/IEAM_2009-026.1
Source: PubMed

ABSTRACT Multitiered frameworks that are designed for risk assessment of contaminated sediment rely on sediment quality guidelines (SQGs) at the first tier or screening level. In the case of contamination by multiple pollutants, results can be aggregated under indices such as the mean quotient. A decision is then reached (e.g., to dispose of dredged materials in open water) without further investigation, provided that the SQGs or the specific values of indices or quotients derived from the SQGs are not exceeded. In this way, SQGs and quotients play a critical role in environmental protection. As part of the development of a tiered framework to assess the environmental risk of materials dredged from the St. Lawrence River, we evaluated various quotients based on SQGs available for this river with a data set that matches chemistry and toxicity test endpoints. The overall efficiency of all tested quotients was rather low, and we then examined factors such as sediment grain size, nutrients, metal-binding phases (e.g., Al, Fe), and dissolved organic carbon to explain misclassified samples. This examination led to the design of a modified tier 1 framework in which SQGs are used in combination with decision rules based on certain explanatory factors.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Purpose The main purpose of this study was to evaluate temporal and regional variability of contamination by heavy metals (HMs) in river sediments using their enrichment factors (EFs) and benchmarking according to sediment quality guidelines (SQGs). The Zlin region in the Czech Republic (Morava and Drevnice River basins) represents a model area where several regionally specific ecological risk assessment studies have recently been conducted with a focus on organic pollution, eco-toxicity, geological, and geochemical characteristics. Materials and methods Four consecutive sediment sampling campaigns were undertaken in spring and autumn 2005–2006. Aqua-regia leachable content of Cd, Co, Cr, Cu, Ni, Pb, Sb, V, and Zn in surface sediments from 14 sites was analyzed using ICP-MS, and Hg content was analyzed using AMA-254 analyzer. EFs were calculated to identify the human impact on pollution in the area. Comparisons to SGQs were conducted to identify the areas and HMs of greatest risk. Results and discussion Calculation of EFs contributed to the effective clustering of HMs. Median EFs of Co, Ni, and V ranged from 0.9 to 1.4 at all sites indicating concentrations very close to natural geological background levels. There was greater enrichment at locally polluted sites, the highest in the cases of Cd, Sb, Hg, and Cr. Widespread influence of diffuse HM sources (traffic, agriculture, and urban wastes) was apparent from elevated concentrations of Pb, Cu, and Zn at all sites. EF values also helped to identify the greatest temporal changes and shifts in HMs contamination between adjacent sites caused by 50-year recurrence interval floods in early spring 2006. The impact was most apparent in downstream sites; namely directly below the confluence of the two major rivers. Conclusions The overall contamination of HMs in the region was classified as low-to-moderate with significantly contaminated sub-areas. The study showed relatively stable spatial distributions of HMs, indicating potential sources of pollution. Cu was identified as the HM of greatest risk. The study emphasizes the necessity of considering both environmental circumstances and background HM occurrence to prevent misinterpretation of the pollution situation. The use of EFs which include grain size proxy normalization and HM background levels, along with the comparison of the detected concentrations to SQGs, proved an efficient way to identify hazardous contamination from anthropogenic sources.
    Journal of Soils and Sediments 08/2013; 13(7). DOI:10.1007/s11368-013-0706-2 · 2.11 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study seeks to determine to what extent trace metals resulting from past mining activities are transferred to the aquatic ecosystem, and whether such trace metals still exert deleterious effects on biota. Concentrations of Cd, Cu, Pb and Zn were measured in streambed sediments, transplanted bryophytes and wild brown trout. This study was conducted at two scales: (i) the entire Morvan Regional Nature Park and (ii) three small watersheds selected for their degree of contamination, based on the presence or absence of past mining sites. The overall quality of streambed sediments was assessed using Sediment Quality Indices (SQIs). According to these standard guidelines, more than 96% of the sediments sampled should not represent a threat to biota. Nonetheless, in watersheds where past mining occurred, SQIs are significantly lower. Transplanted bryophytes at these sites consistently present higher trace metal concentrations. For wild brown trout, the scaled mass and liver indices appear to be negatively correlated with liver Pb concentrations, but there are no obvious relationships between past mining and liver metal concentrations or the developmental instability of specimens. Although the impact of past mining and metallurgical works is apparently not as strong as that usually observed in modern mining sites, it is still traceable. For this reason, past mining sites should be monitored, particularly in protected areas erroneously thought to be free of anthropogenic contamination.
    Environmental Research 09/2014; 134C:410-419. DOI:10.1016/j.envres.2014.07.008 · 3.95 Impact Factor
  • Biophysical Journal 02/2011; 100(3). DOI:10.1016/j.bpj.2010.12.2081 · 3.83 Impact Factor


1 Download