Additives of plastics: Entry into the environment and potential risks to human and ecological health.

A steep rise in global plastic production and significant discharge of plastic waste are expected in the near future. Plastics pose a threat to the ecosystem and human health through the generation of particulate plastics that act as carriers for other emerging contaminants, and the release of toxic chemical additives. Since plastic additives are not covalently bound, they can freely leach into the environment. Due to their occurrence in various environmental settings, the additives exert significant ecotoxicity. However, only 25% of plastic additives have been characterized for their potential ecological concern. Despite global market statistics highlighting the substantial environmental burden caused by the unrestricted production and use of plastic additives, information on their ecotoxicity remains incomplete. By focusing on the ecological impacts of plastic additives, the present review aims to provide detailed insights into the following aspects: (i) diversity and occurrence in the environment, (ii) leaching from plastic materials, (iii) trophic transfer, (iv) human exposure, (v) risks to ecosystem and human health, and (vi) legal guidelines and mitigation strategies. These insights are of immense value in restricting the use of toxic additives, searching for eco-friendly alternatives, and establishing or revising guidelines on plastic additives by global health and environmental agencies.

Biomarkers responses of the clam Anomalocardia flexuosa in sediment toxicity bioassays using dredged materials from a semi-arid coastal system.

Few test organisms are employed for sediment toxicity assessments in Tropical regions, including Brazil. We assessed the ability of the clam Anomalocardia flexuosa to respond to contamination in sediment bioassays using dredging materials of a semi-arid region (Ceará State, NE Brazil), with attention to sublethal responses. Sediments were collected during and after dredging (survey 1 and 2, respectively) and animals exposed in laboratory over 28 days, with responses measured at 7 days. Bioaccumulation of contaminants was determined in whole-body soft tissues as a metric of bioavailability, and biomarkers' changes were monitored in terms of enzymes of phase I and II metabolism, acetylcholinesterase (AChE), and antioxidant responses, lipid peroxidation (LPO) and DNA damage (strand breaks). Clams accumulated aliphatic (AHs) and aromatic hydrocarbons (PAHs), and linear alkylbenzenes (LABs) compared to control conditions (day 0), with increased amounts of As, Cd, Cu, and Zn observed in some samples. The enzyme glutathione S-transferase was enhanced in animals exposed to samples, indicating activation of phase II metabolism. Changes observed in glutathione peroxidase (GPx), glutathione reductase (GR), LPO and strand breaks were related to oxidative stress. AChE enzymatic activity also changed, as an indicator of neurotoxicity caused by sediment exposure. The computed integrated biomarker response index (IBR) ranked sites according to the contamination status and proximity to its sources. Correlations found for biomarkers and bioaccumulation of hydrocarbons indicated the influence of harbor activities, effluent discharges, and urban runoff on the sediment pollution of Mucuripe Bay. Data also showed that SQGs are unable to predict bioaccumulation and subchronic effects. Based on our results we consider that biomarkers responses in A. flexuosa are important endpoints to be applied in sediment toxicity bioassays in tropical regions.

An interdisciplinary approach to assess human health risk in an urban environment: A case study in temperate Argentina.

Unplanned urbanization increases the exposure of people to environmental hazards. Within a landscape ecology framework, this study is a diagnosis of human health risk in San Martín, an urban district of Buenos Aires, Argentina. Risk was estimated by combining four hazard indexes (water and air pollution, and mosquito and rodent infestation) and a vulnerability index. Each index was obtained by integrating environmental and socio-demographic layers in a Geographic Information System. Spatial autocorrelation was assessed for each hazard, vulnerability and risk indexes using Moran's tests. Also, spatial associations between pairs of variables were addressed by means of Geographically Weighted Regressions. The robustness of hazard and vulnerability indexes was checked by a sensitivity analysis. In General San Martín district, 83.3% of the population is exposed to relatively high levels of at least one hazard; 7.4% is exposed to relatively high levels of all hazards (11.5% of the total area) and only 16.7% lives in areas of relatively low levels of all hazards (15.4% of the total area). Areas where hazard intensity was relatively high corresponded to those areas where the most vulnerable population lives, enhancing human health risk. The models for hazards and vulnerability were reasonably robust to changes in the weights of the variables considered. Our results highlight the spatially heterogeneous nature of human health risk in an urban landscape, and reveal the location of critical risk hotspots where reduction or mitigation actions should be focused.

Imidacloprid modifies the mitotic kinetics and causes both aneugenic and clastogenic effects in the macrophyte Bidens laevis L.

Imidacloprid (IMI) is a neonicotinoid insecticide widely used in agricultural activities all around the world. This compound is transported from croplands to surrounding freshwater ecosystems, producing adverse effects on non-target organisms. Because of the relevance of aquatic macrophytes in the above-mentioned environments and the lack of studies of potential effects of IMI on them, this work aimed to assess the mitotic process and potential genotoxicity in the aquatic macrophyte Bidens laevis L. Although the analysis of the Mitotic Index (MI) showed that IMI was not cytotoxic, the Cell Proliferation Kinetics (CPK) frequencies evidenced modifications in the kinetics of the mitotic process. Indeed, the anaphases ratio decreased at 10 and 100 µg/L IMI, while at 1000 µg/L an increase of prophases ratio and a decrease of metaphases ratio were observed. Regarding genotoxicity, IMI produced an increase of the abnormal metaphases frequency from 10 µg/L to 1000 µg/L as well as an increase in clastogenic anaphases-telophases frequency at 100 and 1000 µg/L. In addition, aneugenic anaphases-telophases and C-mitosis frequencies also increased at 1000 µg/L, confirming the effects on the mitotic spindle. Considering the genotoxic effects on B. laevis through two different mechanisms (aneugenic and clastogenic) and the wide spread use of IMI in agriculture, these mechanisms of toxicity on macrophytes should be considered among other recognized effects of this insecticide on aquatic biota.

Application of the Lake Biotic Index (LBI) in the ecological characterization of a North Patagonian lake in Chile.

Increased pollution and degradation of water resources and their associated ecosystems has stimulated the development of tools and methodologies to characterize, estimate, predict, and reverse the environmental impact of anthropic effects on water bodies. The Secondary Water Quality Standards (NSCA) adopted in Chile have incorporated the use of bioindicators complementary to physicochemical analyses, in order to determine the ecological condition of lotic and lentic environments. Our research used the "Lake Biotic Index" (LBI) to establish the ecological condition of Lake Rupanco using benthic macroinvertebrates. The results indicated an Oligo-Eubiotic condition for this lake given the high concentration of oxygen and low organic matter content in sediments, in addition to low biogenic potential and good taxa preservation in both the autumn and spring surveys. Features of the ecological condition obtained through the application of the LBI (benthic subsystem) conform to the results of physicochemical and microalgae analyses undertaken previously in Lake Rupanco (pelagic subsystem). Based on these results, we support application of the LBI index as a complementary tool for the integrated management of lentic ecosystems.

ÍNDICE DE ESTADO LIMNOLÓGICO FLUVIAL PARA LOS RÍOS DE LA CUENCA ALTA DEL RÍO CHICAMOCHA, BOYACÁ-COLOMBIA / INDEX OF FLUVIAL LIMNOLOGICAL STATE FOR THE RIVERS OF THE HIGH BASIN OF THE CHICAMOCHA RIVER, BOYACÁ-COLOMBIA

Se realizó un estudio sobre la cuenca alta del río Chicamocha en Boyacá- Colombia para la construcción de un índice multimétrico con el objetivo de evaluar la calidad ambiental y ecológica de los afluentes y la corriente principal del río Chicamocha. Se evaluaron cuarenta y siete variables entre biológicas, fisicoquímicas e hidráulicas en tres puntos de los ríos Tuta, Jordán y Surba, además de la corriente principal del río Chicamocha. Se seleccionaron nueve variables para la construcción del IELf (Índice de Estado Limnológico Fluvial) puntaje promedio por taxón de invertebrados (ASPT), coliformes totales, porcentaje de saturación de oxígeno disuelto, sólidos disueltos, fosfatos, nitritos, demanda biológica de oxígeno (DBO5), velocidad media de la corriente y profundidad relativa del cauce. De acuerdo con el IELf, el río de peor calidad fue el Jordán; en contraste, el río Surba presentó una condición aceptable. En general toda la cuenca oscila entre un estado malo y crítico (en época seca) debido a la contaminación difusa (proveniente de diversas fuentes) y a la reducción de los caudales. Por otra parte, al comparar el IELf con otros índices de calidad del agua (ICAs) internacionales y colombianos se concluyó que muestra un buen nivel discriminatorio de las condiciones de calidad ambiental y ecológica de sistemas lóticos andinos, como los de la cuenca alta del río Chicamocha.

A study was carried out on the upper Chicamocha river basin in Boyacá, Colombia for the construction of a multi metric index with the objective of evaluating the environmental and ecological quality of the tributaries and the main current of the Chicamocha River. Forty-seven variables between biological, physicochemical and hydraulic were evaluated at three points of the Tuta, Jordán and Surba rivers, in addition to the main stream of the Chicamocha River. Nine variables were selected for the construction of the FLSI (Fluvial Limnological State Index) average score per taxon (ASPT), total coliforms, percentage of dissolved oxygen saturation, dissolved solids, phosphates, nitrites, biological oxygen demand (BOD5), average speed of the current and relative depth of the riverbed.According to the FLSI, the worst quality river was the Jordan; in contrast, the Surba River presented an acceptable condition. In general, the whole basin oscillates between a bad and critical state (in the dry season) due to diffuse contamination (coming from different sources) and to the reduction of the flows. On the other hand, when comparing the FLSI with other international and Colombian water quality indexes (WQIs) it was concluded that it shows a good discriminatory level of environmental and ecological quality conditions of Andean lotic systems, such as those of the Chicamocha river upper basin.