Chloroorganic chemicals emitted from the pulp and paper mill at Nekoski in central Finland were monitored for several years. Concentration time series are used for evaluating the environmental fate and the applicability and validity of an exposure models. Fitted elimination rates of 3,4,5-Tri-, 4,5,6-Tri-, Tetrachloroguaiacol and 2,4,6-Trichlorophenol are approx. 0.22 per day, or rather the half-lives are approx. 3 days. The elimination is most likely by biodegradation and transport-controlled. For 2,3,6-trichloro-p-cymene, fate simulations indicate significant volatilization and sedimentation. Good agreement is achieved with a one-dimensional steady-state box model, except for concentrations in fish. For a reliable assessment of environmental damage, laboratory experiments, monitoring and simulations need to be in tune.

The properties and metal-binding abilities of dissolved organic matter (DOM) rely on its molecular weight (MW) structure. In this study, the spatial differences of DOM in compositions, MW structures, and binding mechanisms with copper (Cu²⁺) in Dongping Lake were investigated by applying excitation-emission matrix combining parallel factor analysis (EEM-PARAFAC), synchronous fluorescence (SF) spectra, two-dimensional correlation spectra (2D-COS), and Fourier transform infrared (FTIR) spectra. The EDOM for the entrance of the Dawen River and PDOM for the macrophyte-dominated region were divided from DOM of Dongping Lake based on hierarchical clustering analysis (HCA) and principal component analysis (PCA) and were size-fractioned into MW < 500 kDa and <100 kDa fractions. According to EEM-PARAFAC, Dongping Lake was dominated by tryptophan-like substances with MW < 500 kDa. The concentration of PDOM was higher than that of EDOM (p < 0.05). 2D-COS showed that protein-like components preceded humic-like components binding to Cu²⁺ regardless of sample type (215 nm > 285 nm > 310–360 nm). The Cu²⁺ binding capacity of DOM exhibited specific differences in space, components, and molecular weights. The humic-like component 1 (C1) and tryptophan-like component 4 (C4) of PDOM showed stronger binding abilities than those of EDOM. Endogenous tryptophan-like component 4 (C4) had a higher binding affinity for Cu²⁺ than humic-like components (logKₐ: C4 > C1 > C2) in PDOM irrespective of MW. Humic-like components with MW < 500 kDa displayed higher binding potentials for Cu²⁺. FTIR spectra showed that the main participants of DOM-Cu complexation included aromatic hydrocarbons, aliphatic groups, amide Ⅰ bands, and carboxyl functional groups. This study provides spatial-scale insights into the molecular weight structure of DOM in influencing the behavior, fate, and bioavailability of heavy metals in lakes.

The presence of heavy metals in municipal solid waste (MSW) is considered as prevalent global pollutants that cause serious risks to the environment and living organisms. Due to industrial and anthropogenic activities, the accumulation of heavy metals in the environmental matrices is increasing alarmingly. MSW causes several adverse environmental impacts, including greenhouse gas (GHG) emissions, river plastic accumulation, and other environmental pollution. Indigenous microorganisms (Pseudomonas, Flavobacterium, Bacillus, Nitrosomonas, etc.) with the help of new pathways and metabolic channels can offer the potential approaches for the treatment of pollutants. Microorganisms, that exhibit the ability of bioaccumulation and sequestration of metal ions in their intracellular spaces, can be utilized further for the cellular processes like enzyme signaling, catalysis, stabilizing charges on biomolecules, etc. Microbiological techniques for the treatment and remediation of heavy metals provide a new prospects for MSW management. This review provides the key insights on profiling of heavy metals in MSW, tolerance of microorganisms, and application of indigenous microorganisms in bioremediation. The literatures revealed that indigenous microbes can be exploited as potential agents for bioremediation.

The first investigation of microplastics in G. affinis from the Brantas River was carried out in this study. Microplastics were found at higher concentrations in gambusia fish captured downstream (209.18 ± 48.85 particles/gram) than upstream (24.44 ± 0.14 particles/gram). Microplastic particle concentrations in G. affinis have a positive linear relationship with fish length. The fiber was the most prominent shape at Sites 1 and 2, whereas the fragment was dominant at Sites 3 and 4. With a value of 45–48%, black dominates the entire site, followed by blue (29–38%), transparent colors (7–11%), red (2–4%), purple (1–3%), and other colors (5–7%). Microplastics measuring <0.1 mm are commonly found in fish bodies. Cyclohexylmethyl octyl ester (phthalic acid) is the most abundant component found in microplastics, accounting for 30.11% of the total. This study provides evidence that G. affinis can be used to monitor the presence of microplastic pollution in the Brantas River but further studies are needed regarding the effects of microplastics and their health hazards on fish.

Rehabilitation is often used to mitigate adverse effects of oil spills on wildlife. With an increase in production of alternatives to conventional crude oil such as diluted bitumen (dilbit), emergency spill responders and wildlife rehabilitators need information regarding the health and survival of free-ranging vertebrates exposed to dilbit under natural conditions. In 2010, one of the largest freshwater oil spills in the United States occurred in the Kalamazoo River in Michigan, when over 3.2 million liters of spilled dilbit impacted 56 km of riverine habitat. During 2010 and 2011 cleanup efforts, thousands of northern map turtles (Graptemys geographica) were captured from oiled stretches of the river, cleaned, rehabilitated, and released. We conducted extensive mark-recapture surveys in 2010, 2011, and 2018–2021, and used this dataset to evaluate the monthly survival probability of turtles 1–14 months post-spill and 8–11 years post-spill based on whether turtles were temporarily rehabilitated and released, overwintered in captivity and then released, or were released without rehabilitation. We found that rehabilitated or overwintered turtles had a higher probability of survival 1–14 months post-spill than non-rehabilitated turtles; however, 8–11 years post-spill the among-group differences in monthly survival probability had become negligible. Additionally, following the oil spill in 2010, nearly 6% of northern map turtles were recovered dead, died during rehabilitation, or suffered injuries that precluded release back into the wild. Our results demonstrate that exposure to dilbit in free ranging turtles causes direct mortality, while effort spent on the capture and rehabilitation of oiled freshwater turtles is important as it increases monthly survival 1–14 months post-spill.

Lead concentrations in hard antlers of adult European roebucks (Capreolus capreolus) were analyzed to assess lead exposure of roe deer roaming the floodplain of the Innerste River, a river system contaminated due to historical metal ore mining, processing, and smelting in its upper reaches. Antler lead concentrations of roebucks culled in the period 1939–2018 within or close to the Innerste floodplain ranged between <0.17 mg Pb/kg (limit of detection) and 51.5 mg Pb/kg (air-dry weight). Median lead concentration in antlers of roebucks culled within the floodplain was 11.1 mg Pb/kg, compared to 2.3 mg Pb/kg in antlers of bucks culled in the floodplain vicinity (P < 0.01). Sampling year had no significant effect on antler lead concentrations (P = 0.748). Lead isotope ratios of antlers from the Innerste downstream area (²⁰⁶Pb/²⁰⁷Pb: 1.179–1.181; ²⁰⁸Pb/²⁰⁶Pb: 2.083–2.085) fell within the range of those reported for hydrothermal vein deposits from the upper catchment area of the Innerste River in the Harz Mountains. Our study demonstrates the long-lasting impact of the historical metal ore mining, processing, and smelting in the Harz Mountains on lead pollution in floodplains of rivers draining this area and the lead exposure of wild herbivores inhabiting the floodplains. Furthermore, it highlights the suitability of roe deer antlers for monitoring environmental lead levels and the usefulness of lead isotope signatures in antlers for source apportionment of lead pollution.