Ecotoxicology

Urban tropical lagoons are commonly impacted by silting, domestic sewage and industrial wastes and the dredging of their sediments is often required to minimize environmental impacts. However, the ecological implications of land disposal of dredged sediments are still poorly investigated in the tropics. Aiming to contribute to filling this gap, an ecotoxicological evaluation was conducted with dredged sediments from Tijuca Lagoon (Rio de Janeiro, Brazil) using different lines of evidence, including soil and sediment characterization, metal determination, and acute and avoidance bioassays with Eisenia andrei...

Artisanal and small-scale gold mining (ASGM) is crucial to the livelihoods of close to 20 million people in over 80 countries, including 4-5 million women, mainly in rural areas with limited alternative economic prospects, particularly in developing countries. ASGM is largely informal, which can add to the challenge of addressing negative social and environmental effects including impacts on biodiversity. However, with proper guidance, ASGM can operate in a responsible manner, using cleaner production methods that minimize impacts on human health and the environment...

Due to their natural history and ecological attributes, turtles are excellent organisms for studies of heavy metal contamination. Turtles have a large geographical distribution, occupy different aquatic habitats, and occupy various trophic levels. The present study investigated mercury bioaccumulation in the carnivorous chelonian Chelus fimbriata (Matamata turtle) and Hg biomagnification in relation to its aquatic food chain in the middle Rio Negro, AM-Brazil. Tissue samples of muscle, carapace and claws were collected from 26 C...

Recently, large-scale fish kills in the Pacific Northwest were linked to tire wear particles (TWPs) left on roadways, with the lethality attributed to 6PPD-quinone. which has a median lethal concentration of <1 µg/L for selected salmonids. However, there remains a paucity of 6PPD-quinone toxicity values developed for estuarine fish species, which is particularly significant because estuaries receiving inflows from highly urbanized watersheds are especially vulnerable to TWP contamination. Therefore, the present study aimed to determine the toxicity of 6PPD-quinone to an economically and ecologically important estuarine-dependent fish-red drum (Sciaenops ocellatus)...

An important provision of the Minamata Convention on Mercury is to monitor and evaluate the effectiveness of the adopted measures and its implementation. Here, we describe for the first time currently available biotic mercury (Hg) data on a global scale to improve the understanding of global efforts to reduce the impact of Hg pollution on people and the environment. Data from the peer-reviewed literature were compiled in the Global Biotic Mercury Synthesis (GBMS) database (>550,000 data points). These data provide a foundation for establishing a biomonitoring framework needed to track Hg concentrations in biota globally...

Wild bees are crucial pollinators of flowering plants and concerns are rising about their decline associated with pesticide use. Interspecific variation in wild bee response to pesticide exposure is expected to be related to variation in their morphology, physiology, and ecology, though there are still important knowledge gaps in its understanding. Pesticide risk assessments have largely focussed on the Western honey bee sensitivity considering it protective enough for wild bees. Recently, guidelines for Bombus terrestris and Osmia bicornis testing have been developed but are not yet implemented at a global scale in pesticide risk assessments...

Metal contamination of the environment poses a significant threat to human health and can cause significant damage to aquatic ecosystems. Danio rerio was exposed to Sorocaba River water for 96 h from two different sites in summer (S) and winter (W). Concentrations of Al, Cd, Cu, Mn and Zn were determined in the exposure water and in sediment. At the end of the exposure, the concentrations of Al, Cu and Mn at the Ibiúna point (P1) and Mn at the Itupararanga point (P2) decreased compared to the initial concentrations in the water...

The annual killifish Austrolebias charrua is an endangered species, endemic to the southern region of South America, which inhabits temporary ponds that emerges in the rainy season. The main anthropogenic threat driving the extinction of A. charrua stems from extensive agriculture, primarily due to the widrespread use of glyphosate-based herbicides near their habitats. Annual killifishes have been used as models for ecotoxicological studies but, up to now, there are no studies about reference genes in any Austrolebias species...

Global pesticide usage reaching 2.7 million metric tons annually, brings a grave threat to non-target organisms, especially aquatic organisms, resulting in serious concerns. Predicting aquatic toxicity of pesticides towards Daphnia magna is significant. In this work, random forest (RF) algorithm, together with ten Dragon molecular descriptors, was successfully utilized to develop a quantitative structure-activity/toxicity relationship (QSAR/QSTR) model for the toxicity pEC50 of 745 pesticides towards Daphnia magna...

Despite the prevalence of discharge of large volumes of heavy-metal-bearing seawater from coal-fired power plants into adjacent seas, studies on the associated ecological risks remain limited. This study continuously monitored concentrations of seven heavy metals (i.e. As, Cd, Cr, Cu, Hg, Pb, and Zn) in surface seawater near the outfall of a coal-fired power plant in Qingdao, China over three years. The results showed average concentrations of As, Cd, Cr, Cu, Hg, Pb, and Zn of 2.63, 0.33, 2.97, 4.63, 0.008, 0...

This study was conducted to ascertain the negative effects of dietary low-density polyethylene microplastics (LDPE-MPs) exposure on growth, nutrient digestibility, body composition and gut histology of Nile tilapia (Oreochromis niloticus). Six sunflower meal-based diets (protein 30.95%; fat 8.04%) were prepared; one was the control (0%) and five were incorporated with LDPE-MPs at levels of 2, 4, 6, 8 and 10% in sunflower meal-based diets. A total of eighteen experimental tanks, each with 15 fingerlings, were used in triplicates...

Platinum group element levels have increased in natural aquatic environments in the last few decades, in particular as a consequence of the use of automobile catalytic converters on a global scale. Concentrations of Pt over tens of μg L-1 have been observed in rivers and effluents. This raises questions regarding its possible impacts on aquatic ecosystems, as Pt natural background concentrations are extremely low to undetectable. Primary producers, such as microalgae, are of great ecological importance, as they are at the base of the food web...

In agroecosystems, insects contend with chemical insecticides often encountered at sublethal concentrations. Insects' exposure to these mild stresses may induce hormetic effects, which has consequences for managing insect pests. In this study, we used an electrical penetration graph (EPG) technique to investigate the feeding behavior and an age-stage, two-sex life table approach to estimate the sublethal effects of thiamethoxam on greenbug, Schizaphis graminum. The LC5 and LC10 of thiamethoxam significantly decreased longevity and fecundity of directly exposed adult aphids (F0 )...

Nanotechnology has grown in importance in medicine, manufacturing, and consumer products. Nanoparticles (NPs) are also widely used in the field of insect pest management, where they show a variety of toxicological effects on insects. As a result, the primary goal of this review is to compile and evaluate available information on effects of NPs on insects, by use of a timely, bibliometric analysis. We also discussed the manufacturing capacity of NPs from insect tissues and the toxic effects of NPs on insects...

With the rapid development of industrialization and urbanization, the issue of copper (Cu) and cadmium (Cd) pollution in aquatic ecosystems has become increasingly severe, posing threats to the ovarian tissue and reproductive capacity of aquatic organisms. However, the combined effects of Cu and Cd on the ovarian development of fish and other aquatic species remain unclear. In this study, female Nile tilapia (Oreochromis niloticus) were individually or co-exposed to Cu and/or Cd in water. Ovarian and serum samples were collected at 15, 30, 60, 90, and 120 days, and the bioaccumulation, ovarian development, and hormone secretion were analyzed...

Mercury contamination from artisanal and small-scale gold mining (ASGM) currently accounts for 37% of the global total, often affecting tropical regions where regulations, if they exist, are often poorly enforced. Ingestion by people and other animals damages the nervous, reproductive, and cognitive systems. Despite the efforts of many organizations and governments to curb mercury releases from ASGM, it is increasing globally. There are many possible interventions, all with significant complexity and cost. Therefore, we recommend taking an established systematic approach to articulate the current situation and construct theories of change (ToC) for different possible interventions for any government or organization trying to solve this problem...

The use of insecticides in agricultural settings often exerts negative effects on nontarget species. Methomyl, a broad-spectrum carbamate insecticide, is recommended to manage a number of insect pests of the cotton crop. Recently, Musca domestica, which is a nontarget insect species in cotton fields, has shown resistance to methomyl in Pakistan. The present study tried to assess resistance-risk assessment, rapidity of resistance development to methomyl, cross-resistance potential to other insecticides, resistance heritability and to forecast the projected rate of resistance development under field conditions...

Accumulation of Arsenic (As) generates oxidative stress by reducing nutrients availability in plants. Arbuscular mycorrhizal (AM) symbiosis can impart metalloid tolerance in plants by enhancing the synthesis of sulfur (S)-rich peptides (glutathione- GSH) and low-molecular-weight nitrogenous (N) osmolytes (proline- Pro). The present study, therefore investigated the efficiency of 3 AM fungal species (Rhizoglomus intraradices-Ri, Funneliformis mosseae -Fm and Claroideoglomus claroideum- Cc) in imparting As (arsenate-AsV -40 at 60 mg kg-1 and arsenite- AsIII at 5 and 10 mg kg-1 ) tolerance in two Cicer arietinum (chickpea) genotypes (HC 3 and C 235)...

Extensive pesticide use for agriculture can diffusely pollute aquatic ecosystems through leaching and runoff events and has the potential to negatively affect non-target organisms. Atrazine and S-metolachlor are two widely used herbicides often detected in high concentrations in rivers that drain nearby agricultural lands. Previous studies focused on concentration-response exposure of algal monospecific cultures, over a short exposure period, with classical descriptors such as cell density, mortality or photosynthetic efficiency as response variables...

Terrestrial soils in forested landscapes represent some of the largest mercury (Hg) reserves globally. Wildfire can alter the storage and distribution of terrestrial-bound Hg via reemission to the atmosphere or mobilization in watersheds where it may become available for methylation and uptake into food webs. Using data associated with the 2007 Moonlight and Antelope Fires in California, we examined the long-term direct effects of wildfire burn severity on the distribution and magnitude of Hg concentrations in riparian food webs...