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The safe disposal of sewage sludge during the process of municipal wastewater treatment has become one of the major concerns of increased production. Land application was thought of as a more economical method for sewage sludge disposal than landfill and incineration. However, the presence of heavy metals in sewage sludge restricted the use of land application. The environmental risk of heavy metals was dependent on their contents, chemical speciations, and soil characteristics. Composting and chemical immobilization were the commonly used methods to immobilize the heavy metals in sewage sludge. The immobilization mechanism and speciation transformation of heavy metals during the composting process were presented. Aluminosilicate, phosphorus-bearing materials, basic compounds, and sulfides were reviewed as the commonly used chemical immobilizing agents. The problems that occur during the immobilization process were also discussed. The combination of different methods and the modification of chemical immobilizing agents both improved the fixation effect on heavy metals.

Management and research of moose (Alces alces) in Alaska, USA, often require chemical immobilization; however, moose may be prone to capture-induced hyperthermia while immobilized. We chemically immobilized moose with carfentanil citrate and xylazine hydrochloride to measure rump fat depth, collect blood and fecal samples, and to deploy modified vaginal implant transmitters and global positioning system (GPS)-collars for recording body temperature and movement during and after the chemical immobilization. We predicted wild moose pursued and captured from a helicopter would have elevated body temperature at time of capture, whereas body temperature would remain stable in hand-raised captive moose not pursued and only hand-injected for immobilization. Additionally, we expected post-capture body temperature would be a function of activity, time immobilized, and ambient temperature. As predicted, body temperature of wild moose was elevated 1 hour after capture (38.9°C, 95% CI=38.7–39.1°C) but returned to baseline levels within 3 hours (38.0°C, 95% CI=37.9–38.1°C); however, body temperatures then rose above baseline levels and remained elevated 12–48 hours post-capture when movement rates were also elevated. Body temperatures in captive moose were not elevated 1-hour post-immobilization (37.9°C, 95% CI=37.8–38.0°C). Body temperatures of wild moose were positively related to cortisol levels at time of capture. Two moose that died after immobilization had initial body temperatures similar to other immobilized moose; however, their body temperature began to rise at 17 hours and 40 hours post-immobilization. Our study provides evidence that chemical immobilization affects body temperature and movement of wild moose up to 48 hours after capture, possibly as a result of renarcotization from carfentanil citrate. With advancements in technology, we recommend fine-scale GPS data (<1-hr fix rates) and continuous body temperature be evaluated to detect evidence of renarcotization during and after opioid-based captures of northern ungulates.

The most common contaminants in the earth’s crust are heavy metals. Remediation is a technique to immobilize, remove, or detoxify these metals in contaminated environments. However, after decades using conventional remediation techniques, new scientific findings indicate that these remediation operations can promote adverse impacts. Given this perspective, a sustainable remediation approach that minimizes environmental, social, and economic impacts has been growing. The objective of this work was to evaluate the chemical immobilization provided by a steel mill industrial waste from the Acid Recovery Plant (ARP) as an alternative to remediate sediments affected by cadmium, lead and zinc. The experiment consisted in adding increasing doses of an ARP industrial residue, consisting mostly of iron oxide, to sediment samples contaminated by a metallurgical industry. After the incubation period, samples from each treatment were removed and submitted to simple extractions (water, acetic acid, DTPA and sodium nitrate) and total pseudo digestion (nitro-perchloric) to determine the bioavailability of Cd, Pb and Zn. The application of the ARP residues provided the formation of complexes associated with the most stable chemical fractions, such as the fraction associated with Fe oxides (F4) and the residual fraction (F5). Treatment with 5% ARP residue was sufficient to reduce the solubility of Cd, Pb and Zn in the sediment studied. Chemical containment proved to be a promising alternative for minimizing the impact of potentially toxic elements (PTEs) in contaminated soils and sediments, as well as being viable from a sustainable point of view.

We investigated intramuscular administration of alfaxalone (5.3–10.0 mg/kg) as an immobilizing agent in free-ranging small Indian mongooses (Urva auropunctata) on the island of St. Kitts, West Indies. From 5–11 January 2020, we successfully immobilized 10 of 11 mongooses. Alfaxalone provided rapid onset (median = 3 min) of immobilization. Mean duration of immobilization was 16.8 ± 3 min. Mean recovery time was 5.6 ± 1 min. There was no effect of dose administered on induction, anesthesia, or recovery times at the dose range used. We concluded that alfaxalone represents an effective alternative to dissociative agents for the immobilization of free-ranging mongooses. Further studies are necessary to quantify alfaxalone effects on mongoose vital rates and blood parameters.

Understanding the effects of capture and handling on wild animals is crucial in evaluating ethical practices in ecological research, and in avoiding biased conclusions from misinterpreting biologging data potentially affected by capture. The aim of this study was to assess the effects of helicopter capture on the behaviour of Scandinavian brown bears by comparing the expression of specific behavioural states between captured bears in spring and bears of a control group that were not captured during the same time period. We identified three different behavioural states: stationary, walking/foraging and transit. Our study revealed that captured bears were more stationary for up to four days after capture compared to bears of the control group, depending on their reproductive state. We found higher doses of the immobilizing drug, as well as abdominal surgery, to negatively impact the bears' movement after capture, highlighting the importance of careful consideration of drug doses and invasive procedures during wildlife capture. This study advances our understanding of the impact of helicopter capture and surgery on the movement of brown bears and helps to refine capture and handling protocols to ensure well‐being and welfare during wildlife capture.

The chemical immobilization of cobalt(II) ions in a silica aerogel matrix enabled the synthesis of the first representative example of aerogel-based single-ion magnets. For the synthesis of the lyogels, methyl-trimethoxysilane and N-3-(trimethoxysilyl)propyl ethylenediamine were co-hydrolyzed, then the ethylenediamine groups that were immobilized on the silica matrix enabled the subsequent binding of cobalt(II) ions. Lyogels with various amounts of ethylenediamine moieties (0.1–15 mol %) were soaked in isopropanol solutions of cobalt(II) nitrate and further supercritically dried in carbon dioxide to obtain aerogels with a specific surface area of 210–596 m2·g−1, an apparent density of 0.403–0.740 cm3·g−1 and a porosity of 60–78%. The actual cobalt content in the aerogels was 0.01–1.50 mmol per 1 g of SiO2, which could easily be tuned by the concentration of ethylenediamine moieties in the silica matrix. The introduction of cobalt(II) ions into the ethylenediamine-modified silica aerogel promoted the stability of the diamine moieties at the supercritical drying stage. The molecular prototype of the immobilized cobalt(II) complex, bearing one ethylenediamine ligand [Co(en)(MeCN)(NO3)2], was synthesized and structurally characterized. Using magnetometry in the DC mode, it was shown that cobalt(II)-modified silica aerogels exhibited slow magnetic relaxation in a nonzero field. A decrease in cobalt(II) concentration in aerogels from 1.5 mmol to 0.14 mmol per 1 g of SiO2 resulted in a weakening of inter-ion interactions; the magnetization reversal energy barrier likewise increased from 4 to 18 K.

Capture and handling of wildlife is often an important component of studies where detailed demographic, behavioral, physiological, or health data are required. Yet, capturing and handling wildlife is sometimes controversial and lacking public support because of concern about effects on individuals. Investigating potential effects of capturing wildlife is also important to inform data-censoring protocols when using information obtained from captured animals. We investigated the short-term effect of helicopter-based capture and handling on movements of free-ranging bison (Bison bison) that were chemically immobilized in Yukon, Canada. We examined daily movement rates, home range size, and displacement of global positioning system-collared individuals immediately after capture and for 20 days thereafter. Our results indicate that there is a minimal short-term effect of helicopter-based capture on bison movements. Significant differences from apparent pre-capture movement behavior were observed only within 24 hours after capture. We observed variation among individuals, however, with some animals taking up to 10 days to return to apparent pre-capture movement rates, whereas others had no measurable response to capture. Despite individual variation, >80% of individuals had returned to apparent pre-capture movement behavior within the first 5 days after capture. Furthermore, sex-based effects were evident: females increased their daily movement rates, home range size, and displacement after capture, whereas males had either no effect or decreased movement rates. Our results suggest that movement rates are altered for only a short period after capture and, therefore, should not have severe negative effects on bison using our protocols. Accordingly, researchers should censor the first 10 days after capture from their analyses to avoid using biased information. Our study should also help inform public discourse regarding capturing and handling wildlife for research or management purposes.

The development, evaluation, and refinement of effective and humane capture methods for wildlife studies is important for increasing our capacity to understand and effectively manageand conserve wildlife populations. Carfentanil has been the primary agent used to chemically immobilize mountain goats (Oreamnos americanus) during the past 40 years. However, carfentanil is no longer commercially available for wildlife captures in North America. To investigate viable alternatives for mountain goat capture, we conducted field trials using thiafentanil to immobilize free-ranging mountain goats via aerial darting methods; thiafentanil responses were then compared to a standard and widely used carfentanil dose. During June–October, 2005–2020, we immobilized mountain goats with either 2.4–3.0 mg carfentanil (n = 444) or 6.0–7.0 mg thiafentanil (n = 68) across a range of different field conditions at 6 different study sites in coastal Alaska. Induction and recovery times were more rapid (and subsequent immobilization times reduced) using thiafentanil compared to carfentanil. In most other respects, however, immobilization characteristics (i.e., body temperature, pulse rate, relative oxygen saturation) were virtually indistinguishable between individuals immobilized with carfentanil or thiafentanil. During typical immobilizations, mean rectal temperature increased 1.8° C, but increased as much as 3.0° C in some extreme cases. Administration of supplemental oxygen resulted in substantial, potentially clinically significant increases in peripheral capillary oxygen saturation, arterial oxygen, and pH in immobilized mountain goats. Our findings indicate that thiafentanil is an effective alternative to carfentanil for chemical immobilization of mountain goats and may offer some important advantages, particularly when immobilizing mountain goats and other species in difficult and potentially dangerous capture environments.

During 17 field seasons between 1973 and 1999, we conducted a long-term study of the behavior of undisturbed wild polar bears in Radstock Bay, southwest Devon Island, Nunavut. In a subset of 11 seasons (6 spring and 5 summer) between 1975 and 1997, we used three different drug combinations to chemically immobilize a small number of adult and subadult polar bears on an opportunistic basis and applied a temporary dye mark so that individual bears could be visually reidentified. We then used multinomial logistic regression to compare the behavior of 35 previously immobilized bears of five different demographic classes (sex, age, and reproductive status) to the behavior of non-immobilized bears of the same demographic classes in the same years and seasons. During the first two days after immobilization, bears slept significantly more and spent less time hunting than did bears that had not been immobilized. However, previously immobilized bears returned to the same behavioral patterns and proportion of total time spent hunting as non-immobilized bears within two days and no further negative behavioral effects were detected in the following 21 d. We visually confirmed successful hunting by three adult bears within 0.4 to 2.1 d of being immobilized, all of which went on to make additional kills within the following 24 h. The return to normal behavior patterns, including the ability to hunt successfully, within 48 h of immobilization appears consistent with the hypothesis that polar bears do not experience longer-term behavioral effects following brief chemical immobilization for conservation and management purposes. 

Large mammals are darted with dart guns to inject drugs or to collect biopsy tissue for capture, research, or veterinary purposes, especially for procedures involving wild and zoo animals. Darting is invasive and associated with risks of trauma, and severe and fatal dart injuries have been reported. Darts fired from CO2‐powered dart guns (CPDG) have a lower risk of injury than those fired from gunpowder‐powered dart guns (GPDG). To avoid serious injuries and other negative effects that might be associated with darting, ballistic data, such as dart velocity and impact energy, and information on the skin characteristics of different target species, are needed. Therefore, we 1) investigated the ballistics of three different CPDG and 2) used wound ballistic methods to test the impact of darts on animal dummies made from ballistic gelatine and fresh hides of the red deer Cervus elaphus, fallow deer Dama dama, roe deer Capreolus capreolus, and wild boar Sus scrofa according to replacement of animal trials within the principle of the 3Rs. We investigated the effects of species, age, body part, and sex on injury severity. Results revealed variations in dart mass within one manufacturer and across all manufacturers were small. For all dart guns, the dart velocity and impact energy increased constantly with increasing distance. The results of the wound ballistic tests showed that each species had a different risk of dart penetration. In addition, there were species‐level variations across age groups and individual‐level variations between shoulder and thigh. In general, the thigh was less sensitive to dart penetration than the shoulder. Based on our observations, we recommend that manufacturers should provide ballistic data for their products. In addition, scientists should publish detailed information on the equipment used for darting to analyse possible dart trauma and avoid further injuries.