Habitat loss and fragmentation together represent the most significant threat to the world's biodiversity. In order to guarantee the survival of this diversity, the monitoring of bioindicators can provide important insights into the health of a natural environment. In this context, we used the comet assay and micronucleus test to evaluate the genotoxic susceptibility of 126 bats of eight species captured in soybean and sugarcane plantation areas, together with a control area (conservation unit) in the Cerrado savanna of central Brazil. No significant differences were found between the specimens captured in the sugarcane and control areas in the frequency of micronuclei and DNA damage (comet assay). However, the omnivore Phyllostomus hastatus had a higher frequency of nuclear abnormalities than the frugivore Carollia perspicillata in the sugarcane area. Insectivorous and frugivorous bats presented a higher frequency of genotoxic damage than the nectarivores in the soybean area. In general, DNA damage and micronuclei were significantly more frequent in agricultural environments than in the control area. While agricultural development is an economic necessity in developing countries, the impacts on the natural landscape may result in genotoxic damage to the local fauna, such as bats. Over the medium to long term, then DNA damage may have an increasingly negative impact on the wellbeing of the local species.

Aquaculture can affect the polyunsaturated fatty acids (PUFA) and mercury (Hg) in fish by altering their diet. Here, planktivorous (silver carp and bighead carp), omnivorous and carnivorous fish with different dietary strategies were selected from two reservoirs, one with on-going aquaculture (WJD) and another without aquaculture (HF) in Southwest China. We compared the total mercury (THg), methylmercury (MeHg) contents and PUFA profiles of fish and their potential diets in these two reservoirs. THg and MeHg contents in omnivorous and carnivorous fish were lower from the WJD Reservoir, which is related to the lower THg and MeHg contents in the artificial fish food. THg and MeHg contents in silver carp from the WJD Reservoir were lower than those from the HF Reservoir, while they were similar in bighead carps from the two reservoirs. The Hg variation in planktivorous fish were inconsistent with that in plankton. THg contents in phyto- and zooplankton from the HF Reservoir were higher than those from the WJD Reservoir, yet their MeHg contents were similar. Artificial fish food which contained higher total PUFA eicosapentaenoic (EPA; 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3), significantly increased the total PUFA and EPA + DHA contents in carnivorous fish, but had less effect on that in omnivorous fish from the WJD Reservoir. Eutrophication caused by aquaculture reduced total PUFA and EPA + DHA contents of plankton in WJD, yet did not reduce those in planktivorous fish. The impacts of aquaculture on Hg and PUFA accumulated in fish were varied among different fish species, and the mechanism needs further exploration.

Antibiotics used in global aquaculture production cause various side effects, which impair fish health. However, the use of dietary composition such as carbohydrate, which is one of the dominant components in fish diets to attenuate the side effects induced by antibiotics, remains unclear. We determined the ability of high carbohydrate diet to protect Nile tilapia (Oreochromis niloticus) from oxytetracycline-induced side effects. Triplicate groups of thirty O. niloticus (9.50 ± 0.08 g) were fed on medium carbohydrate (MC; 335 g/kg) and high carbohydrate (HC; 455 g/kg) diets without and with 2.00 g/kg diet of oxytetracycline (80 mg/kg body weight/day) hereafter, MCO and HCO for 35 days. Thereafter, we assessed growth performance, hepatic nutrients composition and metabolism, microbiota abundance, immunity, oxidative and cellular stress, hepatotoxicity, lipid peroxidation and apoptosis. To understand the possible mechanism of carbohydrate protection on oxytetracycline, we assessed the binding effects and efficiencies of mixtures of medium and high starch with oxytetracycline as well as the MCO and HCO diets. The O. niloticus fed on the MCO and HCO diets had lower growth rate, nutrients utilization and survival rate than those fed on the MC and HC diets, respectively. Dietary HCO increased hepatosomatic index and hepatic protein content of O. niloticus than MCO diet. The O. niloticus fed on the HCO diet had lower mRNA expression of genes related to protein, glycogen and lipid metabolism compared to those fed on the MCO diet. Feeding O. niloticus on the HCO diet increased innate immunity and reduced pathogenic bacteria, pro-inflammation, hepatotoxicity, cellular stress and apoptosis than the MCO diet. The high starch with oxytetracycline and HCO diet had higher-oxytetracycline binding effects and efficiencies than the medium starch with oxytetracyline and MCO diet, respectively. Our study demonstrates that, high carbohydrate partially protects O. niloticus from oxytetracycline-induced side effects by binding the antibiotic. Incorporating high carbohydrate in diet formulation for omnivorous fish species alleviates some of the side effects caused by antibiotics.

Crude oil and its constituents can have adverse effects on ecological and human health when released into the environment. The Canadian Council of Ministers of the Environment (CCME) has developed remedial guidelines and a risk assessment framework for both ecological and human exposure to PHC. One of the assumptions used in the derivation of these guidelines is that plants are unable to take up PHC from contaminated soil and therefore subsequent exposure at higher trophic levels is not a concern. However, various studies suggest that plants are indeed able to take up PHC into their tissues. Consumption of plants is a potential exposure pathway in both ecological (e.g., herbivorous and omnivorous birds, and mammals) and human health risk assessments. If plants can uptake PHC, then the current approach for risk assessment of PHC may underestimate exposures to ecological and human receptors. The present review aims to assess whether or not plants are capable of PHC uptake and accumulation. Twenty-one articles were deemed relevant to the study objective and form the basis of this review. Of the 21 primary research articles, 19 reported detectable PHC and/or its constituents in plant tissues. All but five of the 21 articles were published after the publication of the CCME Canada-Wide Standards. Overall, the present literature review provides some evidence of uptake of PHC and its constituents into plant tissues. Various plant species, including some edible plants, were shown to take up PHC from contaminated soil and aqueous media in both laboratory and field studies. Based on the findings of this review, it is recommended that the soil-plant-wildlife/human pathway should be considered in risk assessments to avoid underestimating exposure and subsequent toxicological risks to humans and wildlife.

Increasing attention has been devoted to the adverse effects of endocrine disrupting chemicals (EDCs) on aquatic environments, such as water, sediment and sludge. To date, few studies have investigated the bio-accumulative characteristics of EDCs in different tissues of diverse wild freshwater fish species and their combined impacts on human health. Five EDCs were investigated in the muscle, liver, gill and, especially, gonad of three fish species collected from the Xiangjiang River, southern China. Carnivorous Siniperca Chuatsi or omnivorous Cyprinus Carpio accumulated higher contents of bisphenol A (BPA) and estrone than herbivorous Parabramis Pekinensis in muscle. Furthermore, 4-n-nonylphenol and estrone were found at higher levels and more frequently in the liver, implying that the liver played an important role in basic metabolism for accumulation, biotransformation and excretion of EDCs. Highest concentrations of BPA found in the gonad revealed that the BPA may pose a serious threat to the reproductive system of aquatic organisms. The mean liver/muscle concentration ratios of 4-n-nonylphenol, BPA, estrone and 17α-ethynyl estradiol confirmed the prolonged exposure of the fish to these EDCs. In addition, the relationships between the fish sizes and the EDC concentrations analyzed by Pearson correlation analysis implied that the bioaccumulation of diethylstilbestrol and BPA increased with the growth of Parabramis Pekinensis, and there was a balance between the uptake rate and elimination rate of EDCs in Siniperca Chuatsi and Cyprinus Carpio. Most importantly, the cumulative impacts of combined EDCs on human health by fish consumption were evaluated. The total estradiol equivalent quantity of estrogens was higher than that of phenols. Also, based on the results of the Monte-Carlo simulation, the 95th percentile values of the total estimated daily intakes from consuming the three freshwater fish species from the Xiangjiang River were higher than the acceptable daily intake.

Increasing heavy metal pollution in wetland ecosystems around the world pose significant health risks to waterbirds, especially the endangered species. We analyzed heavy metal pollution in bird foraging area of Caohai wetland in Guizhou Plateau (China), and used an integrated exposure risk model for assessing heavy metal (Cd, Pb, Cr, Ni, Zn, Sb) exposure risk in birds from the soil, water, plants and benthic invertebrates. There is considerable variation in the extent of heavy metal contamination across the different sampling sites, and Cd and Sb are the main contaminants. The mussel Anodonta showed greater heavy metal accumulation (except for Zn) compared to the snail species C. cathayensis. The different plant species also varied in terms of amount for accumulated heavy metals. The phytophagous together with omnivorous birds were exposed to Cd, Pb, Zn and Ni through plants rather than the soil, whereas the maximum Zn exposure in the omnivorous and carnivorous birds was through consumption of benthic invertebrates. Furthermore, the phytophagous black-necked cranes (Grus nigricollis) were less risk to heavy metal exposure compared to the omnivorous bar-headed goose (Anser indicus) and carnivorous ruddy shelducks (Tadorna ferruginea). The exposure risk of Cr (8.1) was highest, followed by Pb (5.1), Zn (3.8), Sb (1.0), Cd (0.33) and Ni (0.28). The heavy metal assessment heavy metal exposure risk for migratory birds should take into account the exposure from food and soil. Our findings provide new insights into developing measures to minimize heavy metal contamination in migratory birds.

Short chain chlorinated paraffins (SCCPs) are under review for inclusion into the Stockholm Convention on Persistent Organic Pollutants. However, limited information is available on their bioaccumulation and biomagnification in ecosystems, which is hindering evaluation of their ecological and health risks. In the present study, wild aquatic organisms (fish and invertebrates), water, and sediment collected from an enclosed freshwater pond contaminated by electronic waste (e-waste) were analyzed to investigate the bioaccumulation, distribution, and trophic transfer of SCCPs in the aquatic ecosystem. SCCPs were detected in all of the investigated aquatic species at concentrations of 1700–95,000 ng/g lipid weight. The calculated bioaccumulation factors (BAFs) varied from 2.46 to 3.49. The relationship between log BAF and the octanol/water partition coefficient (log KOW) for benthopelagic omnivorous fish species followed the empirical model of bioconcentration, indicating that bioconcentration plays an important role in accumulation of SCCPs. In contrast, the relationship for the benthic carnivorous fish and invertebrates was not consistent with the empirical model of bioconcentration, implying that the bioaccumulation of SCCPs in these species could be more influenced by other complex factors (e.g., habitat and feeding habit). Preferential distribution in the liver rather than in other tissues (e.g., muscle, gills, skin, and kidneys) was noted for the SCCP congeners with higher log KOW, and bioaccumulation pathway (i.e. water or sediment) can affect the tissue distribution of SCCP congeners. SCCPs underwent trophic dilution in the aquatic food web, and the trophic magnification factor (TMF) values of SCCP congener groups significantly correlated with their corresponding log KOW values (p < 0.0001). The present study results improved our understanding on the environmental behavior and fate of SCCPs in aquatic ecosystem.

BPA is chemical pollutant of very high concern due to its toxicity to the environment and risks for human health. Environmental concern consists in BPA entrance into aquatic ecosystems due to acute and chronic toxicity to invertebrates and vertebrates. This study aimed to determine acute BPA toxicity to tropical estuarine-marine species of four trophic levels and integrate BPA toxicity values using species sensitivity distribution (SSD) analysis. Our hypothesis is that BPA toxicity increases towards higher trophic levels. Microalga (Tetraselmis sp.), zooplanktonic grazer (Artemia salina), deposit-feeder invertebrate (Heleobia australis), and omnivorous fish (Poecilia vivipara) were chosen as experimental models. Tetraselmis sp. showed the highest BPA tolerance, without a concentration-dependent response. Species sensitivity have increased from A. salina (LC₅₀,₉₆ₕ = 107.2 mg L⁻¹), followed by H. australis (LC₅₀,₉₆ₕ = 11.53.5 mg L⁻¹), to P. vivipara (LC₅₀,₉₆ₕ = 3.5 mg L⁻¹). Despite the toxicity hierarchy towards trophic levels, which partially supported our hypothesis, SSD did not evidence a clear pattern among estuarine-marine trophic groups. Our study disclosed the sensitivity of not yet investigated species to BPA and, in an integrative way, highlighted BPA toxic effects at different trophic levels. Although estimated acute hazardous concentration (HC5 = 1.18 mg L⁻¹) for estuarine and marine species was higher than environmentally relevant concentrations, sublethal adverse effects induced by BPA exposure may lead to unbalances in population levels and consequently affect the ecological functioning of tropical coastal systems.