Sediment metal enrichment and ecological risk assessment of ten ports and estuaries in the World Harbours Project.

Ten global harbours were assessed for sediment quality by quantifying the magnitude of anthropogenic change and ecological risk. Anthropogenic change (enrichment) was high for Derwent River and Sydney estuary, moderate for Santander Harbour, Rio de Janeiro and Dublin Port, slight for Hong Kong, minimal for Darwin. All 10 enrichment indices used showed similar results. Derwent River sediment was rated at high ecological risk, followed by Sydney and Santander estuaries with moderate risk. Auckland and Darwin sediments exhibited minimal ecological risk and sediment in the remaining harbours (Dublin, Hong Kong, Ravenna, Ria de Vigo and Rio de Janeiro) were assessed at slight ecological risk. The extraordinary variety of environments and types/quantities/qualities of data investigated resulted in as much a critique and development of methodology, as an assessment of human impact, including unique techniques for elemental normalisation and contaminant classification. Recommendations for an improved technical framework for sediment quality assessment are provided.

Metal and Isotope Analysis of Bird Feathers in a Contaminated Estuary Reveals Bioaccumulation, Biomagnification, and Potential Toxic Effects.

The Derwent estuary, in south east Tasmania, is highly contaminated with heavy metals, mainly due to past industrial pollution. This study sought to determine the extent of contamination, bioaccumulation, and biomagnification in the resident bird community and therefore to infer the potential for adverse effects in birds. Thirteen metals were measured from breast feathers (n = 51 individuals) of eight sympatric species of aquatic bird. Stable carbon (δ13C) and nitrogen (δ15N) isotopes were used to identify dietary sources of contaminants, trophic level, and potential biomagnification through food chains. Generalised linear models revealed that metal burdens were often poorly correlated with δ 13C, indicating their uptake from a range of freshwater, brackish, and marine carbon sources-not surprising due to widespread contamination across the tidal estuary. Feather mercury increased significantly with trophic level (inferred from δ15N). White-bellied Sea-eagle Haliaeetus leucogaster samples contained 240 times more mercury than feral Goose Anser cygnoides. Feather arsenic and copper concentrations were significantly higher in birds feeding lower in the food chain. For several piscivorous species, both chick and adults were sampled revealing significantly higher feather mercury, zinc, and selenium in adults. Feathers from birds found dead along the banks of the estuary had significantly higher lead loads than from live birds, and numerous individuals had levels of mercury, zinc, and lead above toxic thresholds reported in other studies. These results highlight the need to include biota from higher trophic levels in contaminant monitoring programs to understand fully the fate and broader implications of contaminants in the environment.

Utilisation of bottom ash in road construction: evaluation of the environmental impact.

France incinerates about 40% of its municipal solid waste (MSW), producing 2.7 million tons of bottom ash annually. Utilisation of bottom ash (BA) is encouraged in France but strictly regulated. Only bottom ash meeting specific criteria and produced in accordance with a quality assurance plan can be used in roadbeds and embankments. In order to evaluate the environmental impact of BA used in road construction under real conditions, two road sections were built: one containing a sub-layer of BA and the other, constructed using only natural gravel to serve as a reference. Water percolating through each roadbed was collected and sampled periodically over three years. Analysis of the samples shows minimal leaching of pollutants from BA. The results are encouraging and indicate that BA utilisation can be safe and can have an environmental impact no greater than that of natural materials.

Utilisation of bottom ash in road construction: a lysimeter study.

The incineration of municipal solid waste (MSW) results in the annual production of 2.7 million tons of bottom ash in France. Utilisation of bottom ash in road construction is encouraged in France but strictly regulated. Because the incinerator residues contain enriched concentrations of metals and salts, particular attention must be focused on the potential environmental problems. In the present study, a laboratory tool (lysimeter) has been developed to reproduce the conditions of bottom ash utilisation and to study their environmental impact via the percolates collected at the bottom of the lysimeter. Four lysimeter experiments were conducted in order to study reproducibility, as well as the influence of water flow rate and pressure on the composition of the percolates. The lysimeter experiments have been then compared with the utilisation of bottom ash under real conditions (two experimental road sections). The comparison of results of lysimeter test and those measured after performing the French standard leach test (AFNOR NF X31-210) shows a recovery of 89% for the chlorides and between 30 and 35% for the sulfates. This indicates that almost all chlorides have been dissolved, contrary to the sulfates, which are less soluble.