Spatial distribution and characteristics of plastic pollution in the salt marshes of Bahía Blanca Estuary, Argentina.

This study delves into the magnitude and attributes of plastic pollution in the salt marshes of the Bahía Blanca Estuary, Argentina, with a specific focus on its spatial distribution. The investigation included the evaluation of microplastics (1-5 mm), mesoplastics (5-25 mm) and macroplastics (25-100 mm), discovering elevated levels along the high salt marsh strandline compared to low salt marsh and mudflat areas. Notably, the abundance of plastic reached staggering levels, reaching up to 20,060 items/m2 in the vicinity of an illegal dumpsite. Microplastics, particularly in the 2-4 mm range, were dominant, and the main plastic components were high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), and polystyrene (PS). Plastic films emerged as the predominant plastic type, while the presence of pellets hinted at potential sources such as illegal dumping and port-related activities. This contamination could be largely attributed to inappropriate waste management practices and urban runoff, which pose a substantial ecological threat to these ecosystems. Urgent remedial action is essential to protect these marshes, underscoring the critical need for comprehensive wetland management and educational initiatives to ensure their long-term sustainability.

Short- and medium-chain chlorinated paraffins in fish from an anthropized south-western Atlantic estuary, Bahía Blanca, Argentina.

Chlorinated paraffins (CPs) are synthetic organic compounds of growing environmental and social concern. Short-chain chlorinated paraffins (SCCPs) were listed under the Stockholm Convention on Persistent Organic Pollutants (POPs) in 2017. Further, in 2021, medium-chain chlorinated paraffins (MCCPs) were proposed to be listed as POPs. We investigated SCCP and MCCP amounts and homolog profiles in four wild fish species from Bahía Blanca Estuary, a South Atlantic Ocean coastal habitat in Argentina. SCCPs and MCCPs were detected in 41% and 36% of the samples, respectively. SCCP amounts ranged from <12 to 29 ng g-1 wet weight and <750-5887 ng g-1 lipid weight, whereas MCCP amounts ranged from <7 to 19 ng g-1 wet weight and <440-2848 ng g-1 lipid weight. Amounts were equivalent to those found in fish from the Arctic and Antarctic Oceans and from some North American and Tibetan Plateau lakes. We performed a human health risk assessment and found no direct risks to human health for SCCP or MCCP ingestion, according to present knowledge. Regarding their environmental behavior, no significant differences were observed among SCCP amounts, sampling locations, species, sizes, lipid content, and age of the specimens. However, there were significant differences in MCCP amounts across species, which could be attributed to fish size and feeding habits. Homolog profiles in all fish were dominated by the medium-chlorinated (Cl6 and Cl7) CPs and shorter chain length CPs were the most abundant, with C10Cl6 (12.8%) and C11Cl6 (10.1%) being the predominant SCCPs and C14Cl6 (19.2%) and C14Cl7 (12.4%) the predominant MCCPs. To the best of our knowledge, this is the first study on the presence of CPs in the environment in Argentina and the South Atlantic Ocean. CP occurrence in the environment, particularly in the food chain, promotes the need for further research on their occurrence and behavior, and the impact of CPs in marine ecosystems in Argentina.

Uptake and detoxification of trace metals in estuarine crabs: insights into the role of metallothioneins.

The detoxification process of trace metals in the estuarine burrowing crab Neohelice granulata, after previously being exposed to anthropogenic pressures in the field, is described for the first time. The objectives of this study were (a) to assess the metal content (Cd, Cu, Pb, Zn, Mn, Ni, Cr, Fe) in the sediments and the uptake of these elements in the hepatopancreas of N. granulata; (b) to quantify trace metal concentrations in the hepatopancreas before and after the detoxification experiment; and (c) to relate this information to metallothionein (MT) induction or reversibility. The detoxification assay was performed for 25 days with artificial seawater under controlled conditions in a culture chamber. The results showed higher uptake and bioaccumulation of Zn and Cu from the sediments, and the hepatopancreas exhibited increased levels of Zn and lower concentrations of the rest of the metals and MTs after the assay, mainly Fe and Mn that were significantly lower. We conclude that trace metals could be translocated to and accumulated in the hepatopancreas, the main metabolic organ, and then eliminated under controlled conditions with corresponding reversibility of MTs. Graphical abstract.

Heavy metal bioconcentration factors in the burrowing crab Neohelice granulata of a temperate ecosystem in South America: Bahía Blanca estuary, Argentina.

An extensive population of the burrowing crab, Neohelice granulata, inhabits the intertidal areas of the Bahía Blanca estuary, a moderately polluted temperate ecosystem located to the southwest of the province of Buenos Aires, Argentina. In order to determine the metal-accumulating ability of this species, concentrations of Cd, Cu, Pb, Ni, Zn, Mn, Cr, and Fe in soft tissues of adult specimens were measured. Subsequently, the bioconcentration factors (BCFs) of all heavy metals were determined using levels of concentrations previously obtained in intertidal sediments. The results showed concentrations above the detection limit in soft tissues of male and female crabs for all metals except Pb and Cr. BCF > 1 were obtained for Cd, Cu, and Zn, indicating that these metals are accumulated and biomagnified. However, BCF values < 1 were found for the rest of the metals (Mn, Ni, and Fe). The findings of metal accumulation in soft tissues of N. granulata is of great importance taking into account that this is a key species within this temperate ecosystem, playing a major role in the transference of pollutants to higher trophic levels.

Toxicological responses of Laeonereis acuta (Polychaeta, Nereididae) after acute, subchronic and chronic exposure to cadmium.

The objective of this study was to analyze the toxicological responses of the estuarine polychaete Laeonereis acuta after acute (96h), subchronic (7 days) and chronic (14 days) exposure to cadmium (Cd). Concentrations of metallothioneins (MT), lipid peroxidation (LPO), total Cd and metal-rich granules (MRG) were evaluated. Seasonal variations of MT and LPO levels in the wild were also measured. Polychaetes were obtained in the Quequén estuary located southeast of Buenos Aires Province, Argentina. For the acute toxicity assay, individuals were exposed to 10; 30, 65; 310; 600; 1300; 2000; 4300; 8100; 16300µgCdL-1, which included levels of environmental relevance and median lethal concentrations (LC50) for related species of polychaete. Based on 96h LC50 values, polychaetes were exposed to sublethal doses of Cd. The concentrations for both subchronic and chronic assays were: 10; 30; 65; 310; 600; 1300; 2000; 4300µgCdL-1. The 96h LC50 value was 8234.9µgL-1, which was within the values reported for other species of polychaete, indicating a high tolerance to Cd. MT induction was not observed for any time exposure. In additoin, LPO levels showed no differences with respect to control levels, which indicated an absence of oxidative damage caused by Cd. However, the total Cd and MRG-Cd concentrations in L. acuta in all tested treatments showed significant differences with respect to control levels. L. acuta were able to accumulate Cd in their tissues in the form of granules which are the main mechanism of Cd detoxification.

Assessment of trace metal accumulation in native mussels (Brachidontes rodriguezii) from a South American temperate estuary.

The present work provides the first results in heavy metal bioaccumulation in the autochthonous mussel Brachidontes rodriguezii from the Bahía Blanca Estuary (Argentina), one of the most important coastal environments of South America, subjected to different anthropogenic pressure. The study is based on the detection of Cd, Cu, Pb, Mn, and Fe in mussels' soft tissue and sediments' fine fraction by means of inductively coupled plasma atomic emission spectroscopy (ICP-OES), in order to analyze the potential relationship between both components of the aquatic system. Additionally, different indices are calculated with the purpose of obtaining detailed data. The heavy metal burden in mussels varied seasonally, showing a clearer pattern for the stations located in the internal area of the estuary. Metals exhibited maximum values in summer and to a lesser extent in winter, followed by a decrease during spring. Multiple international guideline assessment allowed classifying the area as moderately polluted, including a low range for Cd and medium for Cu and Pb. Moreover, the average detected levels were within the measured ranges in other coastal areas. Regarding human health, trace metal content in mussels met the national and international standards for safe consumption.

Exceptionally high Cd levels and other trace elements in eggshells of American oystercatcher (Haematopus palliatus) from the Bahía Blanca Estuary, Argentina.

Concentrations of six trace metals were determined in the eggshells of American oystercatchers (Haematopus palliatus) from the Bahía Blanca estuary, Argentina. All metals measured in selected samples presented concentrations above the detection limit. Means found for Cu, Pb, Cr, Zn and Ni were as follow: 2.02±0.52, 7.23±2.33, 0.78±0.03, 2.22±1.13 and 6.05±0.89mg/kg dw. The mean concentrations of Cd found were surprisingly high: 13.28±3.38mg/kg dw. Previous studies made on prey items of the American oystercatchers showed low to medium concentrations of the six trace metals. This may indicate a possible transfer of the metals that are available in the environment through food chains. Our study indicates that American oystercatchers sequester heavy metals in their eggshells. Therefore the eggshells may be useful as biomonitors for trace metal contamination in the Bahía Blanca estuary.

Latest approaches on green chemistry preconcentration methods for trace metal determination in seawater--a review.

Evaluation of trace metal levels in seawater samples is undertaken regularly by research groups all over the world, leading to a growing demand for techniques involving fewer toxic reagents, less time-consuming protocols and lower limits of detection. This review focuses on providing a brief but concise description of the latest methodologies developed to this end, outlining the advantages and disadvantages of the various protocols, chelating and dispersive agents and instruments used. Conclusions are drawn on the basis of the articles reviewed, highlighting improvements introduced in order to enhance the performance of the protocols.

Burrowing crab (Neohelice granulata) as a potential bioindicator of heavy metals in the Bahía Blanca estuary, Argentina.

Bioindicators can be used to determine spatial and/or temporal variations of heavy metals in a certain coastal or marine environments. This study investigated the potential use of the burrowing crab Neohelice granulata from two different locations in the Bahía Blanca estuary, a moderately polluted ecosystem. Concentrations of zinc (Zn), nickel (Ni), and lead (Pb) in soft tissues of male and female crabs were measured. In addition, concentrations of the three metals in eggs were compared with concentrations in female crabs. No geographical differences were found for any of the three metals, whereas sexual and seasonal differences were obtained for Zn and Ni, with the winter season posing lower concentrations. Moreover, the three metals were detectable in eggs and were lower than concentrations in female crabs (except for Zn). Finally, the usefulness of this species as a potential bioindicator of heavy-metal pollution within this estuarine ecosystem is discussed.

Heavy metals concentrations in zooplankton and suspended particulate matter in a southwestern Atlantic temperate estuary (Argentina).

The present work includes part of the first studies of metals concentrations in the zooplankton from a heavily industrialized estuary of Argentina, the Bahía Blanca estuary. Cd, Cu, and Pb concentrations in the zooplankton (macro- and mesozooplankton) and the suspended particulate matter were measured at stations with different degree of pollution. Physicochemical variables and zooplankton composition and abundance were also analyzed. Thus, the aim of the present work was to analyze the spatial and temporal distribution of heavy metals in these two different fractions, and the possible relation among them due to their importance in the biogeochemical cycles of marine environments. Samplings were carried out during a year, from March 2005 to April 2006, every 2 months, at stations located near chemical and petrochemical industries, stations far from these points and one station in an intermediate location. In the mesozooplankton, the mean concentrations of Cd, Cu, and Pb were 3.63 ± 1.46, 34.46 ± 5.40, and 11.54 ± 3.04 µg g(-1) dry weight (d.w.) respectively, while in the macrozooplankton, 3.20 ± 2.28, 21.86 ± 4.79, and 8.36 ± 1.85 µg g(-1) d.w. On the other hand, particulate Cd, Cu, and Pb presented a mean concentration of 3.33 ± 1.22, 12.75 ± 2.67, and 12.53 ± 3.20 µg g(-1) d.w., respectively. Metals' levels in both the SPM and zooplankton fluctuated throughout the study time and were relatively high in the particulate phase especially for Cu and Pb. Moreover, zooplankton accumulated important concentrations of the three metals. The sources of them are probably the discharges of the industries and domestic sewages located near the estuary.

Heavy-metal concentrations in soft tissues of the burrowing crab Neohelice granulata in Bahía Blanca estuary, Argentina.

Copper (Cu), cadmium (Cd), and chromium (Cr) in soft tissues of male and female burrowing crab Neohelice granulate, as well as their eggs, were measured in two different locations in the Bahía Blanca estuary, a moderately polluted ecosystem, from October 2008 to August 2009. Differences between sexes, sites, and seasonality were assessed. Furthermore, metal levels in eggs were compared with metal levels in female crabs. The results showed no significant differences for Cu and Cd between sexes (Student t test p > 0.25 for both sites) and sites (two-way analysis of variance: Cu p = 0.82 and Cd p = 0.29). Nevertheless, seasonality was found, with winter having significantly lower concentrations for both metals. The range of Cu concentrations was between 96.92 and 152.18 µg g(-1) dry weight (dw), and the range of Cd concentrations was between 6.09 and 10.41 µg g(-1) dw. Cr concentrations could not be assessed because most of the values were lower than the detection limit. Although heavy metals in sediments were not measured in this study, a bioaccumulation process may be occurring for Cd because levels found during the entire sampling period were greater than levels in sediment from previous years. For Cu, a regulation process may be occurring considering that this is an essential metal and levels of Cu in N. granulata found in this study were between 1 and 2 orders of magnitude greater than levels in sediments. Finally, Cu and Cd levels in eggs were detectable, but they were lower than levels in female crabs. The importance of these findings is linked to the fact that metal accumulation seems to be occurring before hatch. The presence of heavy metals in soft tissues as well as in eggs of N. granulata is of great importance considering that this is a key species within the Bahía Blanca estuary; therefore, it plays a major role in the transference of pollutants to greater trophic levels.

The burrowing crab Neohelice granulata as potential bioindicator of heavy metals in estuarine systems of the Atlantic coast of Argentina.

This paper presents the concentrations of total copper, lead, cadmium, and zinc in hepatopancreas of the burrowing crab Neohelice granulata from the Samborombón Bay (La Plata River estuary) and the Mar Chiquita coastal lagoon, Argentina. The highest accumulation of lead was observed in Mar Chiquita samples, whereas copper, zinc, and cadmium concentrations were higher in those from Samborombón Bay. Marked temporal and geographic availability differences were observed, while sexual differences only were observed for zinc. Finally, the validity of using this species as bioindicator of heavy-metal pollution within the assessed estuarine ecosystems is discussed.

Lead concentrations in zooplankton, water, and particulate matter of a southwestern Atlantic temperate estuary (Argentina).

This study presents for the first time valuable results of lead (Pb) accumulation in zooplankton from a southwestern Atlantic temperate estuary, the Bahía Blanca estuary, one of the most important and industrialized coastal environments of Argentina. It considers Pb concentrations in zooplankton organisms as well as in the dissolved and particulate phases. These fractions were analyzed on account of their important role in the biogeochemical cycles of trace elements in estuarine environments. In addition, the major physicochemical variables, i.e., nutrients, and pigment concentrations, and zooplankton composition and abundance, were also considered to understand Pb levels in the above-mentioned fractions. Samplings were performed from March to December 2005 with a bimonthly frequency and comprised a study area with stations located near industrial settlements and other stations a few kilometers far from these points. The results of the physicochemical variables and nutrients and pigments agreed with historic values for the estuary and did not present any evidence of abnormalities. Dissolved Pb presented a mean concentration of 2.15 ± 0.46 µg L(-1), whereas particulate Pb presented a mean concentration of 13.52 ± 3.07 µg g(-1) dry weight (dw). In the mesozooplankton, represented by copepods, the mean concentration was similar to the particulate fraction (13.38 ± 4.41 µg g(-1) dw), whereas in the macrozooplankton, represented by mysids, it was lower (9.81 ± 1.89 µg g(-1) dw). Thus, Pb concentrations were relatively high in the dissolved and particulate phases. Moreover, zooplankton accumulated important concentrations of this metal, which was mainly incorporated through suspended particulate matter (SPM). The source of Pb in all of these fractions is related to the industry discharges as well domestic sewage located near the sampling stations. Finally, through these results, it was possible to show the importance of zooplankton and SPM in the biogeochemical cycle of Pb as well as the interaction between these fractions in an estuarine and anthropogenic environment, such as the Bahía Blanca estuary.