The presence of microplastics (MPs) in freshwater systems that receive discharge of urban effluent implies a great environmental impact. In order to be able to generate proposals that solve this problem, it is necessary to know in detail the contributions of different MPs sources. The aim of this work was to study the contribution of urban sewage discharge to MPs pollution in a stream that runs through a medium-sized city. The spatial distribution of MPs with sizes between 100 μm and 1.5 mm present in surface water was measured and their characteristics, dimensions, shapes and identification were determined. Physical-chemical parameters of the stream water were measured, and a decrease in water quality was found due to wastewater treatment plants. The main source of MPs was effluent from the plants (97% of the total MPs), while the rest came from storm drains and discharge of tributaries. The maximum concentration of MPs found was around 72,000 MP/L (equivalent to 53 million MPs/s), at a point after discharge from both plants. Around 70% of MPs correspond to microfibers with a mean length of around 300 μm and a mean width of around 15 μm, and they are mainly polyethylene fibers. The remaining 30% of MPs are particles with lengths of around 140 μm. The transport of MPs between a point located after discharge of the plants and another point located about 3 km further on was studied, and no significant variation was found in the concentration of MPs. Electrical conductivity was used as a conservative tracer of MPs concentration. This work presents for the first time a detailed analysis of different contributions of MPs to a freshwater system in South America, which receives discharge of wastewater treatment plants, evidencing its important role in pollution.

The dispersion of microplastics (MPs) in coastal and marine environments and their potential harmful effects on organisms and ecosystems makes MPs pollution an emerging problem that has gained increasing attention from the scientific community. Despite the recent increase in the number of studies on MPs presence in different marine environments, investigations in Latin America and the Caribbean (LAC) are still relatively limited. This review presents the spatial distribution (where) and the methods applied (how) in assessing MPs contamination on LAC sandy beaches, identifying the challenges to be faced in advancing the understanding of this emerging contaminant. Most of the 39 papers reviewed were published between 2020 and 2021 (51%) and conducted on Brazilian beaches (43%). The LAC investigations apply spot sampling (69%) on shoreline stretches between 10 and 1000 km (59%). These works used inconsistent sampling methods, incomparable techniques for MPs extraction from sediments, and different measurement units to report their data. The MPs presence on LAC beaches is not negligible, as it varies significantly in its distribution and concentration (0–2457 MP/dw kg and 0–5458 MP/m²). Its highest accumulation is on ocean island beaches; however, there are still large stretches of coastline (Cuba, Venezuela, Argentina) with no data on MPs presence and a small number of studies exploring these contaminants' temporal variability. The lack of standardization in the studies’ methodologies, particularly their measurement units, hinders their quantitative comparison and our ability to establish baseline values regarding MPs abundance on LAC beaches. In this sense, future works should direct efforts towards the spatial and temporal expansion of their sampling, as well as protocol standardization to facilitate result comparability on MPs on LAC sandy beaches.

Environmental observations of antibiotics and other pharmaceuticals have received attention as indicators of an urbanizing global water cycle. When connections between environment and development of antibiotic resistance (ABR) are considered, it is increasingly important to understand the life cycle of antibiotics. Here we examined the global occurrence of erythromycin (ERY) in: 1. wastewater effluent, inland waters, drinking water, groundwater, and estuarine and coastal systems; 2. sewage sludge, biosolids and sediments; and 3. tissues of aquatic organisms. We then performed probabilistic environmental hazard assessments to identify probabilities of exceeding the predicted no-effect concentration (PNEC) of 1.0 μg L−1 for promoting ABR, based on previous modeling of minimum inhibitory concentrations and minimal selective concentrations of ERY, and measured levels from different geographic regions. Marked differences were observed among geographic regions and matrices. For example, more information was available for water matrices (312 publications) than solids (97 publications). ERY has primarily been studied in Asia, North America and Europe with the majority of studies performed in China, USA, Spain and the United Kingdom. In surface waters 72.4% of the Asian studies have been performed in China, while 85.4% of the observations from North America were from the USA; Spain represented 41.9% of the European surface water studies. Remarkably, results from PEHAs indicated that the likelihood of exceeding the ERY PNEC for ABR in effluents was markedly high in Asia (33.3%) followed by Europe (20%) and North America (17.8%). Unfortunately, ERY occurrence data is comparatively limited in coastal and marine systems across large geographic regions including Southwest Asia, Eastern Europe, Africa, and Central and South America. Future studies are needed to understand risks of ERY and other antibiotics to human health and the environment, particularly in developing regions where waste management systems and treatment infrastructure are being implemented slower than access to and consumption of pharmaceuticals is occurring.

Wildlife lead exposure is an increasing conservation threat that is being widely investigated. However, for some areas of the world (e.g., South America) and certain species, research on this subject is still scarce or only local information is available. We analyzed the extent and intensity of lead exposure for a widely distributed threatened species, the Andean Condor (Vultur gryphus). We conducted the study at two different scales: 1) sampling of birds received for rehabilitation or necropsy in Argentina, and 2) bibliographic review and extensive survey considering exposure event for the species' distribution in South America. Wild condors from Argentina (n = 76) presented high lead levels consistent with both recent and previous exposure (up to 104 μg/dL blood level, mean 15.47 ± 21.21 μg/dL and up to 148.20 ppm bone level, mean 23.08 ± 31.39 ppm). In contrast, captive bred individuals -not exposed to lead contamination- had much lower lead levels (mean blood level 5.63 ± 3.08 μg/dL, and mean bone level 2.76 ± 3.06 ppm). Condors were exposed to lead throughout their entire range in continental Argentina, which represents almost sixty percent (>4000 km) of their geographical distribution. We also present evidence of lead exposure events in Chile, Ecuador, and Peru. Lead poisoning is a widespread major conservation threat for the Andean Condor, and probably other sympatric carnivores from South America. The high number and wide range of Andean Condors with lead values complement the results for the California Condor and other scavengers in North America suggesting lead poisoning is a continental threat. Urgent actions are needed to reduce this poison in the wild.

During the past two centuries metal loads in the Earth's atmosphere and ecosystems have increased significantly over pre-industrial levels. This has been associated with deleterious effects to ecosystem processes and human health. The magnitude of this toxic metal burden, as well as the spatial and temporal patterns of metal enrichment, is recorded in sedimentary archives across the globe. This paper presents a compilation of selected Pb contamination records from lakes (n = 10), peat mires (n = 10) and ice fields (n = 7) from Europe, North and South America, Asia, Australia and the Northern and Southern Hemisphere polar regions. These records quantify changes in Pb enrichment in remote from source environments. The presence of anthropogenic Pb in the environment has a long history, extending as far back as the early to mid-Holocene in North America, Europe and East Asia. However, results show that Pb contamination in the Earth's environment became globally ubiquitous at the beginning of the Second Industrial Revolution (c.1850–1890 CE), after which the magnitude of Pb contamination increased significantly. This date therefore serves as an effective global marker for the onset of the Anthropocene. Current global average Pb enrichment rates are between 6 and 35 times background, however Pb contamination loads are spatially variable. For example, they are >100 times background in Europe and North America and 5–15 times background in Antarctica. Despite a recent decline in Pb loads in some regions, most notably Europe and North America, anthropogenic Pb remains highly enriched and universally present in global ecosystems, while concentrations are increasing in some regions (Australia, Asia and parts of South America and Antarctica). There is, however, a paucity of Pb enrichment records outside of Europe, which limits assessments of global contamination.

Artificial light at night (ALAN) is increasing at a high rate across the globe and can cause shifts in animal phenology due to the alteration of perceived photoperiod. Birds in particular may be highly impacted due to their use of extra-retinal photoreceptors, as well as the use of photoperiodic cues to time life events such as reproduction, moult, and migration. For the first time, we used light-logging geolocators to determine the amount of ALAN experienced by long-distance migratory songbirds (purple martin; Progne subis) while at their overwintering sites in South America to measure its potential relationship with spring migration timing. Almost a third of birds (48/155; 31%) were subjected to at least one night with ALAN over 30 days prior to spring migration. Birds that experienced the highest number of nights (10+) with artificial light departed for spring migration on average 8 days earlier and arrived 8 days earlier at their breeding sites compared to those that experienced no artificial light. Early spring migration timing due to pre-migration ALAN experienced at overwintering sites could lead to mistiming with environmental conditions and insect abundance on the migratory route and at breeding sites, potentially impacting survival and/or reproductive success. Such effects would be particularly detrimental to species already exhibiting steep population declines such as purple martins and other migratory aerial insectivores.

The use of bird feathers to assess environmental contamination has steadily increased in ecotoxicological monitoring programs over the past decade. The Olrog’s Gull (Larus atlanticus) is a species endemic to the Atlantic coast of southern South America, constituting one of the three threatened gull species listed in the entire American continent. The aim of this study was to assess the exposure to Persistent Organic Pollutants (POPs) and chlorpyrifos in the Near Threatened Olrog’s Gull through the analysis of body feathers sampled at the Mar Chiquita coastal lagoon, the main wintering area of the species in Argentina, controlling for sex and age class. Chlorpyrifos showed the highest concentrations among all contaminants and groups of individuals (X¯ = 263 ng g⁻¹), while among POPs the concentration of organochlorine pesticides was higher than polychlorinated biphenyls and polybrominated diphenyl ethers, likely indicating the current use of these agricultural contaminant in the region. The highest values of total POP concentrations (males X¯ = 280 ng g⁻¹, females X¯ = 301 ng g⁻¹) were found in juvenile gulls, likely as a consequence of the incorporation of pollutants during the breeding season. Subadult and adult birds showed difference between sexes in the concentration of contaminants, with higher levels in males than females. The results highlight the need to include birds of different sex and age classes in order to better understand the variation in pollutants loads. The present study provides relevant information to improve the conservation status of the Olrog’s Gull and new insights about the environmental health of the Mar Chiquita coastal lagoon, Argentina, a MAB-UNESCO World Biosphere Reserve. However, there is a continued need for long-term monitoring programs focusing on this threatened species to understand the effects of pollutants on its population.

Although estuaries act as a sink of many pollutants, the assessment of microplastics pollution in these transition environments remain scarce or unknown. Sediments from estuarine intertidal areas possess a great ecological concern but also could act as a sink of both buoyant and non-buoyant plastic debris. In this work, we have compared microplastic abundances and their main characteristics (size, shape, colour and polymer type) on intertidal sediments from SW Atlantic Argentinean estuaries (Samborombón, Mar Chiquita, Quequén Grande and Bahía Blanca). The mean microplastics abundance in surface sediments among estuaries was ranged from 0 to 1030 ± 657 items per kg d. w. Upper intertidal areas have shown significant higher microplastic abundances in comparison with lower intertidal zones (p < 0.05). In general, higher mean abundances were observed in surface (0–10 cm) compared to deeper sediments (10–30 cm), which revealed recent deposition trends of microplastics particles. However, higher microplastic abundances were observed in deeper sediments from Bahía Blanca (p < 0.05). Large (MPs, 1–5 mm) and small microplastics (MMPs, 1–0.1 mm) were observed in sediments from all estuaries, representing from 17 to 100% of total microplastics abundance. In terms of shape, fragments and films forms were dominant in all samples while fibers and foams were moderately or poorly represented. White, black, blue and transparent particles were observed as the main colour contribution of microplastics in sediments. The most common polymers identified included polyethylene, polyethylene terephthalate/polyester, polyvinyl chloride and polypropylene. The results showed that microplastic characteristics are different among the estuarine environments, which suggests different anthropogenic sources. Besides, deeper sediments should also be included on intertidal sediment monitoring to identify potential environmental liabilities from anthropogenically impacted estuaries.

Plastic pollution has been reported in sediment, surface water and biota of freshwater systems especially in Europe, North and South America, and Asia with limited studies focussing on African great lakes. This study therefore investigated the occurrence, abundance and distribution of micro-, meso- and macro-plastic debris along shores and sediment of northern Lake Victoria. The abundance of micro-, meso- and macro-plastics measured as particles/kg dry sediment were in range of 0–1102, 0–218 and 0–100 respectively in shoreline sediment and 0–108, 0–33 and 0–77 respectively in lake sediment. The mean abundance of micro-, meso- and macro-plastic debris at fish landing beaches (75.2 ± 50.0, 16.7 ± 8.1 and 18.1 ± 4.6 respectively) were higher than what was recorded at recreational beaches (1.5 ± 0.6, 3.1 ± 3.1 and 3.8 ± 3.8 respectively). Similarly, mean abundance of micro-, meso- and macro-plastic debris in lake sediment were higher in areas of fish landing beaches (9.5 ± 2.6, 2.1 ± 1.5 and 7.7 ± 4.5 respectively) than what was recorded in areas of recreational beaches (0.7 ± 0.7, 0.2 ± 0.1, and 0 ± 0 respectively). Films, filaments, fragments, foam and pellets were the plastic types, with the shoreline sediment dominated by films (>54%) while lake sediment was dominated by filaments (>55%), across size groups (micro-, meso- and macro-plastics). Spearman’s rank correlation indicated strong and significant correlation between abundance of micro- and meso-plastics for total plastic, film plastic and fragment plastic in shoreline sediment. Significant correlation between macroplastics in shoreline sediment and microplastics in lake sediment for total plastics was observed. The FTIR analysis revealed that polyethylene, polypropylene, Polyethylene Terephthalate, Polyamide (nylon), and polyvinyl chloride were the major polymers. These results demonstrated that fish landing beaches along Lake Victoria are hotspot areas for plastic pollution of the lake and should therefore be targeted for management of plastic pollution of Lake Victoria.

The Paraná River basin is one of the most important in South America and is affected by human activities that take place on its margins. In particular, the De la Cruz stream flows through an industrial pole and the Arrecifes River goes mainly through agricultural fields. The aim of this study was to evaluate the water quality of the De la Cruz stream (S1) and the Arrecifes River (S2) by means of physicochemical parameters, including metals and pesticides concentrations. Since amphibians are good indicators of environmental quality, bioassays with Rhinella arenarum were carried on. For lethal and sublethal parameters, embryos and larvae were exposed to a dilution gradient of water samples and AMPHITOX Solution (AS) as negative control for 504 h. For the determination of oxidative stress biomarkers (Catalase -CAT-, Glutathione S-Transferase -GST-, Reduced Glutathione -GSH-, and lipid peroxidation -TBARS-), embryos and larvae were exposed to undiluted water samples and AS. For the determination of micronuclei, larvae at hind limb bud stage (S.28) were exposed to undiluted water samples, simultaneously with negative and positive controls (AS and cyclophosphamide 40 mg/L, respectively). Dissolved oxygen was low in both sites and the copper levels exceeded the Argentine limit for the protection of aquatic life. In embryos exposure, water sample from S1 caused lethal effects (504h-LC50 = 49 (28–71.6)%), increased TBARS levels, and GST and CAT activities. In larvae exposure, water sample from this site decreased CAT activity, while the water sample from S2 caused important lethal effects (504h-LC50 = 98.72 (60.60–302.52)%), low GSH levels and increased GST activity. Water samples from both sites induced higher micronuclei frequency than the negative control. This study alerts about the degradation of water quality of the studied sites including lethal and sublethal effects in R. arenarum that can jeopardize the native populations of this species.