Wetlands are prevalent in the Sudbury, Ontario region and often operate at the interface between terrestrial and aquatic ecosystems, modifying water chemistry and potentially affecting the recovery of impacted lakes. The deposition of metals and sulphur in Sudbury in 2010–2012 was far below that reported in the 1970's, but still higher than background values. Wetlands in the area have accumulated large quantities of metals, and high concentrations of these metals in streams occurred primarily in response to SO4-related acidification events or associated with high dissolved organic carbon production in early summer. Concentrations of most metals in streams exceeded provincial guidelines and fluxes of some metals from catchments exceeded deposition inputs to lakes by as much as 12 times. The release of metals long after emissions reductions have been achieved must be considered in ecosystem recovery studies, particularly as dry conditions may become more prevalent in boreal regions affected by mining.

The AQUATOX model considers the direct toxic effects of chemicals and their indirect effects through foodwebs. For this study, the AQUATOX model was applied to evaluating the ecological risk of Polybrominated diphenyl ethers (PBDEs) in a highly anthropogenically disturbed lake-Baiyangdian Lake. Calibration and validation results indicated that the model can adequately describe the dynamics of 18 biological populations. Sensitivity analysis results suggested that the model is highly sensitive to temperature limitation. PBDEs risk estimate results demonstrate that estimated risk for natural ecosystems cannot be fully explained by single species toxicity data alone. The AQUATOX model could provide a good basis in ascertaining ecological protection levels of “chemicals of concern” for aquatic ecosystems. Therefore, AQUATOX can potentially be used to provide necessary information corresponding to early warning and rapid forecasting of pollutant transport and fate in the management of chemicals that put aquatic ecosystems at risk.

We quantified internal processes that supply methylmercury from hypolimnetic reducing zones to the upper waters of a Hg-contaminated lake, Onondaga Lake, NY, USA. Diffusive transport continuously supplied methylmercury to the epilimnion under summer stratification, while fall mixing resulted in a pulsed release of methylmercury to the upper mixed waters. These processes were the main internal sources of methylmercury to the epilimnion, and together almost equaled the total external supply. The wind-driven entrainment represented an additional stochastic internal supply of methylmercury of approximately 9% in 2006. Considering more than 15 years of data, we estimate 1.8 wind-driven events occur per year. The mass of methylmercury inputs to the epilimnion exceeded the measured increase, suggesting that loss processes are important in regulating methylmercury accumulation. The relative contribution of internal sources of methylmercury to the epilimnion has decreased in recent years, shifting the importance to the external inputs.

The WHAM-FTOX model quantifies the combined toxic effects of protons and metal cations towards aquatic organisms through the toxicity function (FTOX), a linear combination of the products of organism-bound cation and a toxic potency coefficient for each cation. We describe the application of the model to predict an observable ecological field variable, species richness of pelagic lake crustacean zooplankton, studied with respect to either acidification or the impacts of metals from smelters. The fitted results give toxic potencies increasing in the order H+ < Al < Cu < Zn < Ni. In general, observed species richness is lower than predicted, but in some instances agreement is close, and is rarely higher than predictions. The model predicts recovery in agreement with observations for three regions, namely Sudbury (Canada), Bohemian Forest (Czech Republic) and a subset of lakes across Norway, but fails to predict observed recovery from acidification in Adirondack lakes (USA).

Phthalates, such as Di (2-ethylhexyl) Phthalate (DEHP) are compounds extensively used as plasticizer for long time around the world. Due to the extensive usage, DEHP is found in many surface waters (0.013–18.5 μg/L), wastewaters (0.716–122 μg/L), landfill leachate (88–460 μg/L), sludge (12–1250 mg/kg), soil (2–10 mg/kg). DEHP is persistent in the environment and the toxicity of the byproducts resulting from the degradation of DEHP sometime exacerbates the parent compound toxicity. Water/Wastewater treatment processes might play a key role in delivering safe, reliable supplies of water to households, industry and in safeguarding the quality of water in rivers, lakes and aquifers. This review addresses state of knowledge concerning the worldwide production, occurrence, fate and effects of DEHP in the environment. Moreover, the fate and behavior of DEHP in various treatment processes, including biological, physicochemical and advanced processes are reviewed and comparison (qualitative and quantitative) has been done between the processes. The trends and perspectives for treatment of wastewaters contaminated by DEHP are also analyzed in this review.

In this study, the bioaccumulation of perfluorinated compounds from a food web in Taihu Lake in China was investigated. The organisms included egret bird species, carnivorous fish, omnivorous fish, herbivorous fish, zooplankton, phytoplankton, zoobenthos and white shrimp. Isotope analysis by δ13C and δ15N indicated that the carnivorous fish and egret were the top predators in the studied web, occupying trophic levels intermediate between 3.66 and 4.61, while plankton was at the lowest trophic level. Perfluorinated carboxylates (PFCAs) with 9–12 carbons were significantly biomagnified, with trophic magnification factors (TMFs) ranging from 2.1 to 3.7. The TMF of perfluorooctane sulfonate (PFOS) (2.9) was generally comparable to or lower than those of the PFCAs in the same food web. All hazard ratio (HR) values reported for PFOS and perfluorooctanoate (PFOA) were less than unity, suggesting that the detected levels would not cause any immediate health effects to the people in Taihu Lake region through the consumption of shrimps and fish.

The distribution of perfluoroalkyl substances (PFASs) and the isomers of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) was investigated among various tissues (including muscle, gill, kidney, liver) and eggs, in aquatic organisms in Taihu Lake, China. Highest concentration of ΣPFASs was mostly found in liver (278–685 ng/g ww) and eggs (66.0–467 ng/g ww) while the lowest was in muscle (40.6–165 ng/g ww). n-PFOS was the predominant PFOS isomer in most of the tissues with a proportion of 46.3–96.5%. Ratios of PFAS concentrations in eggs to those in liver (E/L) increased positively with the protein-water partition coefficient. The E/L of PFOS isomers descended in the order: linear > monomethyl > diperfluoromethyl isomers. The liver/muscle and kidney/muscle ratios of n-PFOS were higher than branched isomers, suggesting that n-PFOS has higher binding affinity with hepatic proteins or branched isomers are preferentially excreted though liver and kidney.

Hepatic mRNA levels of the dio2 gene (deiodinase 2), implicated in thyroid hormone homeostasis, were analyzed in trout from six remote lakes in the Pyrenees (Spain) and the Tatra Mountains (Slovakia). Highest levels corresponded to fish from the two coldest lakes in Pyrenees, whereas relatively low levels were found in the Tatra lakes. These values correlated with the presence of highly-brominated polybrominated diphenyl ethers (PBDE) congeners in the muscle of the same animals, reflecting the distribution of these compounds across European mountain ranges. In contrast, cyp1a expression levels, diagnostic for the presence of dioxin-like pollutants, mirrored the distribution of semi-volatile organochlorine compounds, indicating the specificity of the two types of biological responses. Exposure to PDBEs is known to increase transcription of dio2 and other thyroid-related genes in laboratory experiments; we propose that our data reflects the same phenomenon in natural populations, driven by anthropogenic pollutants at the environmental concentrations.

EPA, the White House, and electric utilities are stalled in a struggle over a proposed new rule on coal ash disposal. Although this rule is long overdue, EPA now stands on the cusp of bringing forward a landmark decision that could benefit aquatic resources in the USA for decades to come and also set an important regulatory leadership example for the international community to follow. However, multi-million dollar wildlife losses are continuing to pile up as things stall in Washington. In this commentary I use a newly reported example, Wildlife Damage Case 23, to further illustrate serious flaws in the National Pollutant Discharge Elimination System that EPA's new rule can address. Case 23 provides additional impetus for EPA and the White House to move swiftly and decisively to end surface impoundment disposal of coal ash and the associated toxic impacts to wildlife.

The first nationwide survey of six phthalic acid esters (PAEs) (diethyl phthalate (DEP); dimethyl phthalate (DMP); di-n-butyl phthalate (DBP); butyl benzyl phthalate (BBP); bis(2-ethylhexyl) phthalate (DEHP); di-n-octyl phthalate (DnOP)) in source waters was conducted in China. The results showed these PAEs were ubiquitous in source waters. DBP and DEHP were the most frequently detected with high concentrations ranging nd–1.52 μg/L and nd–6.35 μg/L, respectively. These PAEs concentrations (except DBP) in surface water (rivers, lakes and reservoirs) were generally higher than those in groundwater; DBP had high concentrations in groundwater in Northeast China (Liao River Basin) and North China (Hai River Basin). Their concentrations in the northern regions were generally higher than those in the southern and eastern regions; particularly, in North China. Three short-chain PAEs (DMP, DEP and DBP) were detected with high concentrations in Hai River Basin, Pearl River Basin and Yellow River Basin.