Organotin compounds in Brachidontes rodriguezii mussels from the Bahía Blanca Estuary, Argentina

Wastewater in Latin American urban peripheries: Identifying research trends and challenges through a systematic literature review

Water is a defining element for cities and their inhabitants. Throughout urban systems, water is either produced or received, used, and finally disposed of as wastewater. As Latin American urbanization accelerates, problems related to wastewater are increasing due to its inclusion as the main source of river pollution, as well as the high cost of infrastructure development and maintenance. The consequences of wastewater disposal are particularly relevant in areas frequently associated with urban expansion, like peripheries whose growth follows constant transitions between rural, peri-urban, and urban areas. Such consequences are often related to heterogeneity, lack of urban services and sanitation infrastructure, water pollution and health risks, as well as the development of informal compensatory systems. A systematic literature review was conducted to broaden research panorama and identify spatial, temporal, and thematic trends and challenges present in wastewater assessments of Latin American urban peripheries, this using the SALSA (search, appraisal, synthesis, and analysis) protocol in a search through international databases Scopus and Web of Science Scielo, in English, Spanish, French, and Portuguese. In these databases, 228 papers satisfied selection criteria and show a growing trend of publications about urban wastewater since 1988. Most case studies are from Brazil (58 %), Mexico (14 %), and Argentina (9 %). Their main approaches are quantitative research (82 %) in urban contexts (57 %). Most studies were found to be operationalized using environmental geochemistry methodologies, suggesting a dominance of technical, reductionist approaches. Integrated and mixed perspectives including actors and other societal elements are suggested as a central research challenge. Without an integrated view, it will be unfeasible to enhance decision-making processes and governance in the pursuit of sustainable water management.

Tracking synthetic microdebris contamination in a highly urbanized estuary through crabs as sentinel species: An ecological trait-based approach

Synthetic microdebris (particles of <5 mm) are a worldwide concern because they can affect the community structure of the aquatic ecosystems, organisms, and even food webs. For the biomonitoring of synthetic microdebris (especially microplastics, MPs), mainly benthic invertebrates are used, but crabs have been less studied in the literature. We studied the synthetic microdebris contamination in water, sediments, and three representative intertidal crabs (Neohelice granulata, Cyrtograpsus angulatus and Leptuca uruguayensis) with different lifestyles from the Bahía Blanca estuary, Argentina. The results obtained show the presence of cotton-polyamide (PA), polyethylene (PE), and polyethylene terephthalate (PET) in surface waters. In sediments, we identified cellulose modified (CE), polyester (PES), polyethylene (PE), and alkyd resin, while in crabs, cotton-PA and CE were the predominant ones. The MPs abundance ranged from 8 to 68 items L^-1 in surface water, from 971 to 2840 items Kg^-1 in sediments, and from 0 to 2.58 items g^-1 ww for the three species of crabs. Besides, paint sheets ranged from 0 to 17 in the total samples, with Cr, Mo, Ti, Pb, Cu, Al, S, Ba and Fe on their surface. There were significant differences between the microdebris abundances in the abiotic matrices but not among crabs species. The ecological traits of the different crabs helped to understand the accumulation of synthetic microdebris, an important characteristic when determining the choice of a good biomonitor.

Distribution of Butyltin Compounds in the Coastal Environment of the Bahía Blanca Estuary, Argentina

This study evaluates for the first time the distribution and accumulation of butyltin compounds (BTs) in different compartments such as seawater, sediments, suspended particulate matter (SPM), and mussels (Brachidontes rodriguezii) in the Bahía Blanca estuary. The samples were collected from six sampling sites with different anthropogenic impacts. A better visualization and interpretation of data was achieved using chemometric tools (Tucker4 model), which made it possible to reveal the main relationships among the variables. This analysis showed the presence of BTs in all the estuarine environmental compartments, even in sites with low human intervention. The relationships found among BTs levels, seasons, and environmental matrices show the importance of biological processes such as phytoplankton blooms and remobilization of sediments (by tidal dynamics and/or periodic dredging) in BTs distribution and degradation. In addition, partition coefficients showed that mussels mainly bioaccumulate tributyltin from sediment, water and, to a lesser extent, SPM.

Fast and easily obtained information about mobilizable metals from sediment samples. Extraction assisted by benzothiophene-based ionic liquids

A fast and easy method for trace metal extraction on sediments was developed in our laboratories. Three new stable S-metylbenzothiophenium salts were employed along with microwaves to modify the BCR protocol to obtain the concentration of metals of the first two fractions in only one step. The optimum conditions were obtained with 0.125 g of sediment irradiated at 250 W for 30 s at 120 °C, in 5 ml of an aqueous mixture of 10 mM of 1,2-dimethylbenzothiophenium tetrafluoroborate and 0.5 M of hydroxylamine chlorhydrate at pH 2. The method validation was carried out employing BCR 701. The extracted metals were determined by ICP OES. A student's paired t-test was applied with the reference method, giving satisfactory results.

Effects of chlorothalonil on the antioxidant defense system of mussels Perna perna

Chlorothalonil is an effective fungicide used in agriculture and formulations of antifouling paints, which use and possible toxicity has been generating great concern. Thus, the present study investigated the effects of chlorothalonil on the antioxidant defense system (ADS) of the mussel Perna perna. The ADS was evaluated in gills and digestive gland after 24 h and 96 h of exposure to environmental relevant levels of chlorothalonil (0.1 and 10 μg/L). The activity of the enzymes superoxide dismutase (SOD), catalase (CAT), glutamate cysteine-ligase (GCL) and glutathione S-transferase (GST), levels of non-enzymatic defenses, represented by glutathione (GSH), and lipoperoxidation (LPO) and protein carbonyls (PCO) were evaluated. Results indicated that exposure to chlorothalonil is affecting the ADS in both tissues. While the activity of SOD increased and GST and GSH were not altered in gills, they decreased in digestive gland after 24 h of exposure to 10 μg/L of chlorothalonil. The contrasting results indicate that gills and digestive gland presented different patterns of responses after exposure to chlorothalonil. Moreover, a tissue-specific response to chlorothalonil was observed. Gills could be acting as the first line of defense, presenting higher enzymatic levels with minor effects on the parameters analyzed. On the other hand, digestive gland, with lower levels of antioxidant defenses, was the most affect organ by chlorothalonil. It also should be highlighted that the fungicide reduced the glutathione metabolism in the digestive gland, which can lead to an imbalance of the redox state within the cells of animals.

Responses of the mussel Brachidontes rodriguezii to aerial exposure: implications on growth and physiological condition

The length of aerial exposure (i.e., environmental conditions) of an organism, due to daily tides, induces physiological responses. A mark–recapture field experiment was conducted in two intertidal zones (low tide and high tide) using the stain calcein AM to determine growth, as measured by shell length, of the mussel Brachidontes rodriguezii (d’Orbigny, 1842) along its vertical distribution off the north Argentinean coast. In the high intertidal zone, B. rodriguezii exhibited slower growth in shell length because of the physiological stress resulting from aerial exposure during low tides. In the low intertidal zone and during spring, B. rodriguezii exhibited faster growth in shell length. It is suggested that growth of B. rodriguezii relies on several environmental factors (temperature, photoperiod, and aerial exposure) that fluctuate according to tidal height.

Spatiotemporal distribution of organotin compounds in the coastal water of the Bahía Blanca estuary (Argentina)

Several areas within the Bahía Blanca estuary (BBE), with different maritime traffic intensity, were studied in order to confirm the presence and assess the distribution of tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) in the water column. The organotin compounds (OTCs) were determined in the water samples-taken in summer, autumn, winter, and spring of 2014-by gas chromatography coupled to mass spectrometry after liquid-liquid extraction with hexane. The incidence of TBT throughout the whole sampling period indicated a continuous presence of this compound to the study area. However, in accordance with the butyltin degradation index (BDI), TBT was not recently introduced in the BBE. Furthermore, the average TBT levels exceeded the international guideline established by the Oslo-Paris commission (0.62 ng Sn L^-1). As a result, certain biological effects could be expected to occur in sensitive species such as mussels. While DBT were below the detection limit in the 75% of the samples analyzed, MBT was detected in all the samples and no significant differences were found among the concentrations measured in the different seasons (Kruskal-Wallis test, p > 0.05). In addition, no correlations were found among the OTCs levels and the evaluated physiochemical parameters (Spearman coefficient, p > 0.05).

Urgent caution to trace organometal pollution: Occurrence, distribution and sources of methyltins, butyltins and phenyltins in sediments from South Hangzhou Bay, China

The concentrations of seven organotin compounds (OTCs) were determined seasonally in 22 sediment samples (brackish, freshwater and shrimp pond sediments) in South Hangzhou Bay, China. For the brackish and freshwater sediments, methyltins of up to 43.0 ng Sn g^-1 dw showed no significant variation with seasons or locations (p > 0.05). However, butyltin levels in summer (44.0 ± 30.2 ng Sn g^-1 dw) were about two folds higher than those in spring (20.4 ± 18.7 ng Sn g^-1 dw) and four folds higher than in autumn or winter (both≈10 ng Sn g^-1 dw), which is mainly attributed to the heavy contamination near the shipyard, mariculture and textile plants in summer. Phenyltins in spring reached the peak level of 28.4 ng Sn g^-1 dw, about three times of other seasons. Meanwhile, there was a significant variation of phenyltins in summer with high-value sites also in the vicinity of mariculture. Thus, excepting the contribution of agricultural activities to phenyltins, mariculture is likely to be a potential source of butyltins and phenyltins into the marine environment (particularly in summer). This hypothesis has been partly validated by determining adjacent shrimp pond sediments, which showed ubiquitous contamination of butyltins and phenyltins in summer and spring (14.2-44.2 ng Sn g^-1 dw and 2.2-16.9 ng Sn g^-1 dw), but only one sample had the detectable methyltin levels with 8.8 ng Sn g^-1 dw of momomethyl-tin. On the other hand, seven OTCs showed a stronger affinity to brackish sediments than the adjacent freshwater sediments, probably owing to the differences of physicochemical parameters and microbial activities in sediments. Overall, OTC contaminants have become more diversified and complicated in coastal zones, suggesting that future studies should pay attention to other OTC species like phenyltins and methyltins, not only the butyltins.

Multiple-biomarker approach in the assessment of the health status of a novel sentinel mussel Brachidontes rodriguezii in a harbor area

The objective of this study is to analyze whether a combination of biomarkers at different levels of biological complexity could be used to assess the health status of a population of Brachidontes rodriguezii associated to a harbor area in Mar del Plata, Argentina. A battery of biomarkers of general stress was measured in mussels collected from impacted and non-impacted areas. This included: condition index; shell analysis; histopathological alterations; atrophy and integrity of the digestive gland tissue; changes in cell type composition of the digestive gland, and glycogen accumulation. The studied biomarkers were integrated into the Integrative Biological Response (IBR/n) index. Overall, the IBR/n indicated a higher level of stress in mussels located in the harbor area. Thus, this biomarker index is a sensitive analytical tool that could be used to classify the ecotoxicological risk in coastal sites.

Organotin contamination in commercial and wild oysters from China: Increasing occurrence of triphenyltin

Organotin contamination in marine environment has been a public concern for many years due to its adverse impacts on biota and human health. This study investigated levels, distribution and health risks of six organotin compounds: tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT), triphenyltin (TPhT), diphenyltin (DPhT) and monophenyltin (MPhT) in commercial and wild oysters in China. The total organotin in commercial oysters ranged from 251 to 1949 ng Sn g^-1 dw (dry weight) >. Two endocrine disruptors TBT and TPhT were detected in these samples with the highest level of 68.1 ± 20.1 ng Sn g^-1 dw and 747 ± 7.3 ng Sn g^-1 dw, respectively. For wild oysters, the concentrations of total organotins varied from 33.3 to 2671 ng Sn g^-1 dw. Butyltins were dominated by TBT with the mean level of 26.1 ± 30.0 ng Sn·g^-1 dw and showed no significant spatial variation between the southern and northern coastal zones (p > 0.05). However, compared with the north, phenyltin levels especially TPhT were much higher in the south coastline (246-1484 ng Sn·g^-1 dw) due to the wider use of TPhT-based biocides in local mariculture and agriculture. Health risk assessment indicated that a daily exposure of TPhT-contaminated oysters (including commercial and wild ones) may pose adverse threats to human particularly children as the risk quotients (RQ) were higher than 1. Organotin contamination (e.g., TPhT) still occurs in the South China's coastal zones after the TBT ban, which deserves future research and effective measures to protect the marine ecosystem and human health.

Preliminary studies about the role of physicochemical parameters on the organotin compound dynamic in a South American estuary (Bahía Blanca, Argentina)

This work provides a preliminary study of the destination, mobility, and availability of tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) in contaminated sediments and water column within Puerto Rosales Port, located in the middle zone of the Bahía Blanca Estuary (Argentina). Therefore, this study presents the first comprehensive results of the role of several physicochemical parameters (temperature, pH, Eh, salinity, turbidity, organic matter, chlorophyll, and macronutrients) in behavior of organotin compounds (OTCs) in a marine-coastal ecosystem. The samples were collected seasonally in May, August, and November during 2014. Levels of OTCs were determined in sediments and water column samples by means of gas chromatography-mass spectrometry analysis. Degradation index analyses suggested not recent inputs of TBT at the area of study. However, results submitted a continuous input of TBT into the column water; further, its distribution and degradation pattern were shown to be influenced by salinity, turbidity, particulate organic matter, chlorophyll, and nitrates. These last two parameters, chlorophyll and nitrates, also were very important for sediment samples. Chlorophyll together with high temperatures recorded in the surface sediments triggers biodegradation process of TBT and DBT resulting in high MBT levels while nitrates seemed to promote debutylation process. Furthermore, pH appeared to influence drastically the adsorption/desorption activity of TBT and DBT in sediment. Finally, the Eh obtained suggested a degradation of TBT thanks to the presence of Fe (III) in this compartment. In addition, in fact, the results outlined a possible MBT additional input that contributes to the pollution observed in the study area. Graphical abstract Organotin compounds behavior according to several physicochemical parameters.

Assessment of the organotin pollution in the coastal sediments of the Western Arabian Gulf, Saudi Arabia

Organotin compounds (OTCs) are persistent pollutants and are considered as chemicals of environmental concern. They enter the marine environment from the antifouling paints containing organotin compounds on the hulls of ships and boats. We report the results of a study conducted in 2015 on the level of butyltins (TBT, DBT, and MBT) and phenyltins (TPhT, DPhT, and MPhT) in the sediments collected from three fishing harbors (Jubail, Khobar, and Qatif) and a reference site (Half Moon Bay). The concentrations of OTCs in the sediments vary widely among the different sampling locations. Overall, the phenyltins contribute more than the butyltins and the order of the abundance is: MPhT > DPhT > MBT > DBT > TPhT. In most stations, the concentrations of MBT are higher than DBT. The sediments from Khobar and Qatif are moderately polluted, whereas those from the Jubail are ranked as highly polluted. The concentrations of TBT at all study sites are less than the detection limit, and hence, the environmental and ecotoxicological risks are low.