An “on site” bioremediation program was designed and implemented in soil polluted with polycyclic aromatic hydrocarbons (PAHs), especially naphthalene. We began by characterizing the soil's physical and chemical properties. A microbiological screening corroborated the presence of microorganisms capable of metabolizing PAHs. We then analyzed the viability of bioremediation by developing laboratory microcosms and pilot scale studies, to optimize the costs and time associated with remediation. The treatment assays were based on different types of biostimulants, such as a slow or fast-release fertilizer, combined with commercial surfactants. Once the feasibility of the biostimulation was confirmed, a real-scale bioremediation program was undertaken in 900 m3 of contaminated soil. The three-step design reduced PAH contamination by 94.4% at the end of treatment (161 days). The decrease in pollutants was concomitant with the selection of autochthonous bacteria capable of degrading PAHs, with Bacillus and Pseudomonas the most abundant genera.

A pot experiment was conducted to investigate the solubility and redox species of antimony (Sb) in a relocated shooting range soil and its uptake by Lolium perenne L. and Holcus lanatus L. under different water regimes. After 1-week waterlogging, the total Sb concentration in soil solution decreased from ∼110 μg L−1 to <20 μg L−1, and slowly increased over the following 4 weeks, with the dissolution of Fe and Mn (hydr)oxides. In this process, half of the Sb in soil solution was reduced to Sb(III), which greatly affected the plant uptake of Sb. Waterlogging increased shoot Sb concentrations of L. perenne by ∼10 fold but decreased uptake in H. lanatus by 80%. Results indicate that Sb might primarily be taken up as Sb(III) by L. perenne and as Sb(V) by H. lanatus. Temporary waterlogging of soil may increase the risk of trace elements entering the food chain.

In this study, the aqueous uptake and dietary assimilation (trophic transfer) of two endocrine disrupting compounds (dioxin and phathalic acid) in the green mussel Perna viridis were quantified. During short-term exposure period, dioxin rapidly sorbed onto phytoplankton and its accumulation was much higher than that of phthalate. The uptake of these two compounds by the mussels increased with increasing temperature and salinity (for dioxin only). The dietary assimilation of the two contaminants was rather modest (10–64% for dioxin and 20–47% for phthalate), and was greatly dependent on the food species and concentration. Interestingly, dietary assimilation increased with increasing diatom food concentration. Gut passage time was partially responsible for the variable dietary assimilation. Given the high dissolved uptake rate and the modest dietary assimilation, aqueous exposure was predicted to be the dominant bioaccumulation source for both dioxin and phthalate in the green mussels under most conditions.

In this study we explore the use of fish otoliths (‘earbones’) as a tool for detecting exposure to heavy metals in sediments. Because otoliths are metabolically inert and incorporate chemical impurities during growth, they can potentially provide a more permanent record of pollutant exposure history in aquatic environments than soft tissues. To validate this technique we cultured embryos of a native Australian fish, the common Galaxias (Galaxias maculatus), in the laboratory on sediments spiked with copper in a concentration gradient. Our aims were to test whether exposure to copper contaminated sediments is recorded in the otoliths of embryos and determine over what range in concentrations we can detect differences in exposure. We found elevated copper levels in otoliths of embryos exposed to high copper concentrations in sediments, suggesting that otoliths can be used as a tool to track a history of exposure to elevated copper levels in the environment.

Silver nanoparticles (AgNPS) are an important model system for studying potential environmental risks posed by the use of nanomaterials. So far there is no consensus as to whether toxicity is due to AgNPs themselves or Ag+ ions leaching from their surfaces. In sea urchin Paracentrotus lividus, AgNPs cause dose dependent developmental defects such as delayed development, bodily asymmetry and shortened or irregular arms, as well as behavioural changes, particularly in swimming patterns, at concentration ∼0.3 mg/L AgNPs. It has been observed that AgNPs are more toxic than their equivalent Ag+ ion dose.

Bioaccessibility tests can be used to improve contaminated land risk assessments. For organic pollutants a ‘sink’ is required within these tests to better mimic their desorption under the physiological conditions prevailing in the intestinal tract, where a steep diffusion gradient for the removal of organic pollutants from the soil matrix would exist. This is currently ignored in most PBET systems. By combining the CEPBET bioaccessibility test with an infinite sink, the removal of PAH from spiked solutions was monitored. Less than 10% of spiked PAH remained in the stomach media after 1 h, 10% by 4 h in the small intestine compartment and c.15% after 16 h in the colon. The addition of the infinite sink increased bioaccessibility estimates for field soils by a factor of 1.2–2.8, confirming its importance for robust PBET tests. TOC or BC were not the only factors controlling desorption of the PAH from the soils.

Egypt is a major agricultural country in Africa with a known past of organochlorine pesticides (OCPs) application, yet data on atmospheric levels of OCPs in Egypt is sparse. Low density polyethylene (LDPE) passive samplers were therefore deployed for 3 weeks each at 11 locations in July, 2010 and January, 2011 in Alexandria to screen for gas-phase OCPs. Performance reference compounds were used to investigate the uptake kinetics. Field-derived sampler-air partitioning coefficients (KPE-As) for OCPs were significantly correlated against the compounds' subcooled liquid vapor pressure (log PL): [log KPE-A = −0.77 ± 0.07*log PL + 6.35 ± 0.13 (R2 = 0.90; n = 17; SE = 0.19; p < 0.001)]. Estimated and measured OCP concentrations in Alexandria agreed well (factor difference ≤ 2) indicating the feasibility of monitoring OCPs using LDPEs. OCP concentrations ranged from <LOD to 168 pg/m3. Calculated isomeric ratios indicated recent usage of chlordanes and endosulfans.

Spatial and temporal changes in mercury (Hg) concentrations and organic carbon in lake sediments were examined from the Hudson Bay Lowlands to investigate whether Hg deposition to sediments is related to indicators of autochthonous production. Total organic carbon, “S2” carbon (mainly algal-derived OC), C:N and ∂13C indicators suggest an increase in autochthonous productivity in recent decades. Up-core profiles of S2 concentrations and fluxes were significantly correlated with Hg suggesting that varying algal matter scavenging of Hg from the water column may play an important role in the temporal profiles of Hg throughout the sediment cores. Absence of significant relationship between total Hg and methyl Hg (MeHg) in surficial sediments suggested that inorganic Hg supply does not limit MeHg production. MeHg and OC were highly correlated across lakes in surface and deep sediment layers, indicating that sediment organic matter content explains part of the spatial variation in MeHg concentrations between lakes.

Concentrations of metals associated with sediments have traditionally been analysed to assess the extent of heavy metal contamination in freshwater environments. Stream biofilms present an alternative medium for this assessment which may be more relevant to the risk incurred by stream ecosystems as they are intensively grazed by aquatic organisms at a higher trophic level. Therefore, we investigated zinc, copper and lead concentrations in biofilms and sediments of 23 stream sites variously impacted by urbanisation. Simultaneously, biofilm bacterial and ciliate protozoan community structure was analysed by Automated Ribosomal Intergenic Spacer Analysis and Terminal Restriction Fragment Length Polymorphism, respectively. Statistical analysis revealed that biofilm associated metals explained a greater proportion of the variations observed in bacterial and ciliate communities than did sediment associated-metals. This study suggests that the analysis of metal concentrations in biofilms provide a good assessment of detrimental effects of metal contaminants on aquatic biota.

Karst systems represent important yet vulnerable drinking water resources. A wide spectrum of pollutants may be released into karst groundwater from agriculture, livestock farming, private households, and industry. This work provides an overview on the occurrence and dynamics of micropollutants in a karst system of the Swiss Jura. Ten months of intensive monitoring for micropollutants confirmed that the swallow hole draining an agricultural plain was the main entry path for pesticides into the karst system and the two connected springs. Elevated fungicide concentrations in winter and occasional quantification of pharmaceuticals suggested wood- or façade treatment and domestic sewer as additional sources of contamination. A continuous atrazine signal in the low ng/L range might affect the autochthonous endokarst microbial community and represents a potential risk for the human population through karst groundwater.