Butyltin compounds and their relation with organic matter in marine sediments from San Vicente Bay-Chile

Update on the status of the contamination by organotin compounds in sediment of Nuevo Gulf, Argentina. Insights from field and experimental studies

Organotin compounds are persistent pollutants and are considered chemicals of high environmental concern. In the present study, the distribution and degradation of tributyltin were evaluated in field sediments and through an ex situ experiment. For this, sediment samples from two locations were analysed: Luis Piedrabuena Harbour, with higher maritime traffic, and Cerro Avanzado, which receives less impact from anthropogenic activities. The results indicated that pollution levels at Luis Piedrabuena Harbour have decreased compared with studies performed 9 years ago for the same area. On the contrary, traces of organotin compounds have been found for the first time at Cerro Avanzado. Moreover, the butyltin degradation index indicated that organotin compounds undergo an advanced degradation process in the collected samples at both sites. Ex situ experiments revealed a limited capacity of sediments to retain tributyltin, and suggested an active role of bioturbation activity in the degradation of these compounds. In addition, visualisation using chemometric techniques (principal components analysis) allowed a simpler analysis of two sediment characteristics: the degree of contamination and the degradation levels of organotin compounds.

Occurrence, sources and environmental risk assessment of organic micropollutants in coastal sediments from the Atacama Region (Chile)

Nowadays, there is still a scientific knowledge gap regarding occurrence and distribution of organic contaminants in remote areas. In this study, we have monitored for the first time the presence of a wide range of persistent and emerging organic pollutants in the Atacama Desert coastal region (Chile), a key area in the Humboldt Current System. Nonylphenols (NPs), polycyclic aromatic hydrocarbons (PAHs), pesticides, UV filters, synthetic fragrances, and organophosphate flame retardants (OPFRs) were determined in sediments along the >500 km length Atacama coastline. NPs, well-known endocrine disruptors, were the predominant pollutants in the area (up to 333.5 ng g-1 dw). We identified inputs of different classes of contaminants from anthropogenic activities such as mining, agriculture, direct effluent discharges, harbors, energy plants, recreational activities, and tourism occurring along the coastline. Environmental risk assessment through calculation of hazard quotients (HQs) showed a high ecological risk level for NPs in the three provinces of Atacama (HQ >1). In the case of PAHs, (pyrene, benz(a)anthracene, chrysene, acenaphthene, naphthalene and benzo(a)pyrene) HQ >1 was showed in Copiapó province. Furthermore, estradiol equivalent concentrations (EEQ) were determined to estimate estrogenicity of the environmental sediment samples. The maximum EEQ value was for NPs in H1 (Carrizal Bajo wetland), province of Huasco, where the highest concentration of NPs was found. The sampling point H1 is a particular location because it is the exit of a wetland and a tourist point used as a beach. The potential risks of anthropogenic chemical substances impacting remote regions such as the one studied here highlight the need of expand monitoring efforts worldwide for a better assessment of the global pollution status.

The first observation of antifouling organotin compounds and booster biocides in sediments from Samsun Port area, Black Sea, Turkey

The distribution of antifouling organotin compounds (OTCs) and booster biocides in surface sediments of Samsun Port (Black Sea, Turkey) in September 2014 was investigated by gas chromatography-tandem mass spectrometry (GC-MS/MS) method. The total organotin concentrations ranged from <1.0 to 669.6 ng/g, dw. Among the studied booster biocides, Diuron (<1.0-11.28 ng/g) was found in 70.58% of the investigated sediments, while Irgarol (<1.0-26.53 ng/g) was detected in two stations. Traces of fresh input organotin and high Irgarol were found at the park/repairment points of the port. The Principal Component Analysis (PCA) showed that sediment characteristic types and Total Organic Carbon (TOC) were the main relevant parameters in the accumulation of antifouling contamination in the Port area. In comparison with several types of environmental sediment quality criteria, Samsun Port is highly polluted area. The concentrations of OTCs and Diuron maybe used as a baseline reference level for future monitoring programs in Turkish Ports.

Spatial distribution of butyltins and imposex in eastern Brazilian Amazon

Spatial distribution of Butyltins (BTs) in surface sediments and gastropod tissues were quantified, with samples taken from an estuarine system of the Eastern Amazon, Brazil. The imposex incidence was also assessed using Thaisella coronata (Gastropoda, Mollusca). The sediment sampling was carried out at 19 sites and T. coronata in 6 of those. The highest BTs levels were detected in sediments of a Marine Extractive Reserve (27.1 ng Sn g^-1) and in an urban area (19.8 ng Sn g^-1). In T. coronata tissues, BTs levels ranged from <5 to 142 ng Sn g^-1. Imposex incidence ranged from 0% to 100% and VDSII (penile papillae) was registered in gastropods from 5 out of 6 sampled sites. The results suggest that BTs concentrations are related to sampled area use, but also to the local hydrodynamics, highlighting the importance of an effective control in the use of TBT-based antifouling paints in the Eastern Amazon.

Are antifouling residues a matter of concern in the largest South American port?

In the present study, levels of booster biocides (diuron, Irgarol, chlorothalonil, dichlofluanid and DCOIT), butyltin compounds (TBT, DBT and MBT) and antifouling paint particles (APPs) were assessed in sediments of areas under the influence of the largest Latin American port, marinas, boat traffic and ship/boat maintenance facilities located within Santos-São Vicente Estuarine System (SSES). Contamination profile was directly related to local maritime activities, where sediments from the main navigation channel (MNC) presented low levels of antifouling residues while adjacent areas (AA), characterized by the presence of boats and boatyards, showed higher contamination considering all analyzed residues. Moreover, areas under the influence of fishing boats/yards presented relevant levels of butyltins (ΣBTs > 300 ng g^-1) and APPs (>100 μg g^-1), while marinas dominated by recreational boats showed higher booster biocides occurrence. Sites located nearby shipyards in the MNC and boatyards in the AA presented expressive amounts of APPs (>200 μg g^-1). These APPs represent an important long-term source of biocides to the SSES. Thus, the profile of maritime activities in association to local oceanographic conditions drive the spatial distribution of antifouling residues within SESS, which in some case presented levels above sediment guidelines for TBT, DCOIT and diuron.

Assessing the Efficacy of a Sediment Remediation Program Using Benthic and Pelagic Copepod Bioassays

Tributyltin is an organotin chemical that has been commonly used in ship antifouling paints. Despite the global total prohibition of tributyltin-based paint in 2008, tributyltin continues to be found at toxic levels in areas of high maritime traffic such as ports and harbors. A remediation program was conducted at a New Zealand port to reduce tributyltin and copper concentrations to acceptable values. The present study assessed the efficacy of the program using a combination of chemical analyses and copepod bioassays. Sediment and water samples were collected at 3 locations along a spatial gradient within the port, and concentrations of various organotin compounds and trace metal levels were measured pre- and postremediation. The toxicity of sediment and elutriate samples was estimated by benthic and pelagic copepod bioassays. Although acute toxicity in sediment samples was reduced following remediation, reproductive success was still affected for the benthic copepod. This approach combining chemical analysis and bioassays is promising for assessing the efficacy of remediation processes at contaminated marine sites. Environ Toxicol Chem 2020;39:492-499. © 2019 SETAC.

Organotin compounds in touristic marinas of the northern Adriatic Sea: occurrence, speciation and potential recycling at the sediment-water interface

Butyltin compound (BTC) contamination was evaluated in two north Adriatic marinas, San Rocco (Italy) and Lucija (Slovenia). BTC sedimentary concentrations (121 ± 46 and 352 ± 30 ng Sn g^-1 in San Rocco and Lucija, respectively) evidenced the past use of antifouling paints, confirmed by the reduced tributyltin content (~ 46%) with respect to the sum of BTC. Elemental and organic carbon isotopic (δ¹³C) analyses of bulk sediments and its lipid and humic substances were performed in order to evaluate their role in BTC partitioning and preservation. The δ¹³C of sedimentary bulk and refractory organic matter suggested that diagenetic processes could play a role in the preservation or release of pollutants. No contamination was found in water collected from the benthic chamber and thus, fluxes at the sediment-water interface were not assessed, except for MBT efflux at Lucija (28.9 ng Sn m^-2 day^-1). Nevertheless, BTC concentrations in porewaters (up to 75 ng Sn l^-1) and rather low sediment-porewater partitioning coefficients (K_d) with respect to the data reported in the literature would suggest a potential risk of the reintroduction of BTC into the water column at both sites: at Lucija, sedimentary contamination is high despite the greater Log K_d, whilst at San Rocco, the low BTC concentration is associated with a reduced sediment affinity.

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.

Distribution of butyltins at dredged material dumping sites around the coast of China and the potential ecological risk

Previous research has found butyltin pollution at dumping sites, which are the final fate of dredged material mostly originating from harbors and navigation systems. The distribution and impacts of butyltins were assessed in sediments at 12 dumping sites of China. Total butyltins (monobutyltin, dibutyltin, and tributyltin) concentrations ranged from 1.76 to 486.62 ng Sn g^-1 dw. This study also presents evidence of considerable historic inputs of tributyltin (TBT) to Dumping sites 01, 05, 06, 08, 09 and 11, with evidence of heavier recent TBT input at Dumping site 04 and 10. The butyltin contamination at dumping sites was comparatively light and historic compared to research in other countries, but was more serious than other sea regions. TBT levels at Dumping site 09 probably have negative effects on biological systems. Overall, more attention should be paid to the level and impacts of butyltins in the sediment at dumping sites in China.

Fast and Feasible Ultrasound-Assisted Pretreatment for the Determination of Organotin Compounds in Environmental Samples

The goal of this study was to improve an already established reference method, such as the one devoted to organotin compounds determination (Reference Method for Marine Pollution Studies, No. 59, UNEP). The proposed upgrade consists of replacing the mechanical shaking by ultrasound energy and applying low temperature throughout the whole procedure. The optimization of the new operational conditions was performed by using a factorial design. Quality control was performed using a certified sediment reference material (PACS-2) for sediments (82.5-97% of recovery) and recoveries on spiked samples for suspended particulate matter (SPM) and mussels (94-100%). The proposed procedure was applied to surface sediment samples, SPM, and native bivalve mollusks (Brachidontes rodriguezii) collected in Bahia Blanca estuary, a very industrialized zone. The relative standard deviation (RSD %) of the environmental samples were less than 7.9%. It is important to note that the proposed procedure reduced the sample pretreatment time about seven times.

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

Levels of tributyltin and its breakdown compounds, including the first record of monobutyltin (MBT) in history for Latin America, were determined in native mussels (Brachidontes rodriguezii) by means of CG-MS, after extraction/derivatization assisted by ultrasound. The samples were collected in 2013 in Bahía Blanca Estuary (Argentina) at 6 sites, which reflect different levels of maritime activities. Total butyltins (TBts = TBT+ DBT+ MBT) levels ranged from 19.64 to 180.57ng Sn g^-1 dry weight. According to the Oslo-Paris commission, the results indicated that 73.9% of mussels could be under biological effects risks associated with TBT pollution. In accordance with the calculated bioaccumulation factors, approximately 56% of samples appeared to have accumulated TBT through the sediments. All sampling sites were shown to be impacted by organotin compounds (OTCs) showing variable levels through seasons, which could be related with the variation of the water temperature. Degradation index analyses suggested aged inputs of TBT possibly under a general degradation process at the area of study. In addition, the occurrence of DBT and MBT could not be uniquely attributed to the degradation pathway of the TBT; in fact, results outlined the possible contribution of some punctual and diffuse sources at the area such as proximity to plastic industries, industrial effluents, sewage outlets and domestic wastewaters.

Butyltin contamination in Northern Chilean coast: Is there a potential risk for consumers?

Imposex is the superimposition of non-functional male sex organs in gastropod females. This syndrome is a hormonal imbalance induced by tributyltin (TBT) which have been used in antifouling paints formulation. The present study aimed to perform an integrated environmental assessment of imposex and butyltin (BT) contamination using surface sediments and tissues of Thaisella chocolata (an edible gastropod) from northern Chile. The results showed imposex incidence in 11 out of 12 sites. In the most contaminated sites, which are areas under the influence of maritime activities, and also used for fishing and aquaculture, RPLI were over 60 and VDSI over 4 (high incidence of sterile females). Exceptionally high contamination levels and evidences of fresh inputs of tributyltin (TBT) were detected along the studied area. TBT levels above 300 and 90ngSng^-1, respectively, were recorded in sediments and edible gastropod tissues of 6 sites. Thus, a daily ingestion of 90 to 173g of T. chocolata foot (4 to 8 organisms) from the most contaminated sites will certainly lead to the consumption of BT exceeding the tolerable daily intake recommended by European Food Safety Authority. It is reasonable to consider that human risk is even higher if daily consumption of additional seafood is considered. Moreover, some contaminated sites were located within the marine reserve "Isla Grande Atacama", indicating that even marine protected areas are under the influence of TBT contamination. These findings suggest that current levels of TBT in the studied area are sufficient to induce harmful effects on the environment and constitutes a potential threat to seafood consumers. Thus, national regulatory actions toward environmental protection and food safety of local populations are still mandatory, even after 8years of the TBT global ban by IMO.

Tributyltin bioaccumulation and toxic effects in freshwater gastropods Pomacea canaliculata after a chronic exposure: field and laboratory studies

Freshwater samples and gastropod mollusks (Pomacea canaliculata) were collected at 5 sampling stations located along the lower Río de la Plata basin, Argentina, to assess the extent of tributyltin (TBT) contamination. Determined data revealed the presence of TBT and some of its breakdown products (dibutyltin: DBT, and monobutyltin: MBT) in all freshwater samples and also in soft tissues of P. canaliculata gastropods. Chronic bioassays (6 months) were performed using female gastropods that had been reared under laboratory conditions and exposed to a similar TBT concentration than the value determined in freshwater samples (1 µg L^-1). The aims of this study were to evaluate the extent of TBT accumulation, the tissue distribution, and the effects on selected biomarkers (activity of superoxide dismutasa: SOD, activity of catalase: CAT, levels of total glutathione: t-GSH, lipid peroxidation, and activity of acetylcholinesterase: AChE). Gonads presented the highest accumulation, followed by the cephalopedal region, albumin gland, and finally hepatopancreas. Both metabolites, DBT and MBT, were also found. All exposed female animals presented development of a penis reflecting the potential of TBT as an endocrine disrupting chemical for this gastropod species. Results on the selected biomarkers confirmed additional adverse effects induced by TBT. An increase in CAT activity and changes in t-GSH levels are indicative of alterations on the cellular redox status. The inhibition of AChE could reflect signs of neurotoxicity. Altogether, these results reveal a negative impact on the health of this gastropod population.

Imposex and butyltin contamination still evident in Chile after TBT global ban

Imposex in gastropods (Acanthina monodon, Oliva peruviana and Xanthochorus cassidiformis), butyltin levels in surface sediments (Coquimbo and Concepcion) and tissues (Valparaiso and Concepcion) were assessed in three areas under the influence of maritime activities along the central Chilean coast. The highest TBT concentrations were observed in São Vicente Bay (Concepcion), reaching 122.3ngSng(-1) in surface sediments and 59.7ngSng(-1) in gastropods tissue, while in Valparaiso ranged from 7.4 to 15.8ngSng(-1) in biota. The lowest TBT concentrations were detected in sediments from Coquimbo (<2ngSng(-1)), which can be attributed to a much lower ship/boat traffic (probably using TBT free products) in association to local oceanographic conditions. Despite DBT and MBT were the predominant analytes, recent inputs of TBT were evident in some areas. In fact, fishing boats may be a relevant source since they were the predominant maritime activity in the most contaminated sites. In addition, the absence of significant differences within BTs levels between both genders of A. monodon suggests that tissues from distinct sexes can be indistinctly used for future contamination studies. Imposex incidence was detected in 11 out of 15 sampled sites, indicating that environmental levels of TBT have been sufficient to induce deleterious effects on the exposed organisms. Thus, the impacts caused by TBT in Chilean coastal areas were detectable and consistent with other studies performed in South America. This present environmental contamination is probably due to the lack of regulations forbidding the use of TBT-based antifouling paints in Chile.

Spatiotemporal appraisal of TBT contamination and imposex along a tropical bay (Todos os Santos Bay, Brazil)

A spatiotemporal evaluation of butyltin contamination was performed between 2010 and 2012 along Todos os Santos Bay (Northeast Brazil) using surface sediments, bivalve tissues (Anomalocardia brasiliana and Mytella guyanensis), and imposex occurrence (Stramonita rustica). The spatial study detected high tributyltin (TBT) levels (maximum values of 262 ng Sn g (-1) - 21,833 ng Sn g(-1) of total organic carbon - for surface sediments and 421 ng Sn g(-1) for bivalve tissues) in the innermost part of the bay. The TBT levels detected in M. guyanensis tissues might cause human health risk since local population consumes these organisms. These high concentrations observed in the bivalves might result in ingestions higher than the safe limits established by European Food Safety Authority (250 ng TBT kg(-1) day(-1)). Considering the temporal evaluation, no difference (p > 0.05) was observed between TBT concentrations in sediments obtained during the two sampling campaigns (2010/2011 and 2012). However, the increasing predominance of TBT metabolites (butyltin degradation index (BDI) >1) in more recent sediments indicates further degradation of old TBT inputs. In spite of that, recent inputs are still evident at this region. Nevertheless, a reduction of imposex parameters in S. rustica over the last decade suggests an overall decline in the TBT contamination, at least in the outermost and possible less impacted region of the bay. The TBT contamination is probably reducing due to the national and international legislative restrictions on the use of TBT as antifouling biocide. The contamination levels, however, are still relevant especially in the inner part of Todos os Santos Bay since they are above those that are likely to cause toxicity to the biota.

Butyltin and PAH Contamination of Mar del Plata Port (Argentina) Sediments and Their Influence on Adjacent Coastal Regions

The distribution of butyltins (BTs) and polycyclic aromatic hydrocarbons (PAHs) were studied in surface sediments to assess how relevant is Mar del Plata port (Argentina) as a source of contamination to the surrounding environments. Within the port, TBT concentrations ranged from 24.2 to 150 ng Sn g(-1) and PAHs (Σ16) from 180 to 17,094 ng g(-1). At the surrounding beaches, PAHs were detected at low concentrations and TBT concentrations reached 10.9 ng Sn g(-1). Although those low levels indicate that the Port might not be an important source of contamination to the surrounding beaches, the very low TOC content and the coarse grain size of the beaches sediments could explain the sedimentary levels. The results show a reduction in TBT levels in Mar del Plata port after national and international use restrictions of TBT-based antifouling paints.

Evaluation of the use of Olivella minuta (Gastropoda, Olividae) and Hastula cinerea (Gastropoda, Terebridae) as TBT sentinels for sandy coastal habitats

Tributyltin (TBT) contamination is still recorded in the environment even after its ban in antifouling paints. Since most biomonitors of TBT contamination, through imposex evaluation, are hard-bottom gastropods, the identification of soft-bottom sentinels has become useful for regions where rocky shores and coral reefs are absent. Thus, an evaluation of Olivella minuta and Hastula cinerea as monitors of TBT contamination was performed in two sandy beaches located under influence area of São Sebastião harbor (São Paulo state, Brazil), where previous and simultaneous studies have reported environmental contamination by TBT. In addition, the imposex occurrence in H. cinerea was assessed in an area with low marine traffic (Una beach), also located in São Paulo State. A moderate imposex incidence in O. minuta was detected in Pernambuco (% I = 9.36, RPLI = 4.49 and RPLIstand = 4.27) and Barequeçaba (% I = 2.42, RPLI = 0.36 and RPLIstand = 0.81) beaches, indicating TBT contamination. In contrast, more severe levels of imposex were recorded for H. cinerea in Una beach (% I = 12.45) and mainly in Barequeçaba beach (% I = 98.92, RPLI = 26.65). Our results suggest that O. minuta and H. cinerea have good potential as biomonitors for TBT based on their wide geographical distribution, common occurrence in different coastal sediment habitats, easy collection, and association with TBT-contaminated sediments.

Venezuelan Caribbean Sea under the threat of TBT

Although environmental tributyltin (TBT) contamination is considered a solved problem, imposex occurrence in Plicopurpura patula as well as butyltins (BTs) contamination in sediments and tissues were detected along 700 km of the Caribbean coastal shore. Areas under the influence of five main ports of Venezuela were covered, as well as large marinas and sites located away from expected sources. Marinas were the most contaminated areas, whilst imposex incidence and TBT levels were relatively low in areas nearby commercial harbors. Thus, it is evident that marinas have become the main source of fresh TBT to the region. This might explain why imposex incidence seems to be widely distributed along the Venezuelan coast, since leisure boats are circulating along the whole coastal region. In fact, this could be the pattern for other areas of the Caribbean Sea.

High tributyltin and imposex levels in the commercial muricid Thais chocolata from two Peruvian harbor areas

The first appraisal of butyltin (BT) contamination linked with imposex incidence in Peruvian coastal areas was performed in the present study. Imposex occurrence and BT levels in female bodies were analyzed in the rock snail Thais chocolata distributed along 10 sites in areas under the influence of Callao and Chimbote Harbors. Imposex levels associated to high tributyltin (TBT) concentrations were observed in six of 10 studied sites, and the highest imposex levels were seen in gastropods collected near the harbor terminals. Tributyltin concentrations were the highest reported for gastropod mollusks (up to 662 ng Sn g(-1)) in recent studies. Although TBT-based antifouling paints have been banned globally (International Maritime Organization, 2008), the combination of high imposex and TBTs level with butyltin degradation index values indicated fresh TBT inputs in these Peruvian coastal areas. Thus, the need to implement local regulatory strategies related to the use of TBT-free antifouling paints is urgent, as is a thorough assessment of the effectiveness of the TBT global ban. Moreover, the wide distribution of T. chocolata combined with its capability to elicit imposex and bioaccumulate BTs renders this a good sentinel species for TBT contamination along the western South American coast.

Organotin contamination in South American coastal areas

Organotin compounds (OTs) were used in antifouling paints for more than four decades. However, due to their widespread intensive use and high toxicity, undesirable effects in non-target marine organisms have been detected since the early 1980s. Consequently, the International Maritime Organization banned new maritime applications of these products on January 1, 2003 and their presence on ship hulls from January 1, 2008. Although extensively studied in Europe, North America, Oceania, and Asia, environmental levels and effects of organotin contamination are still poorly known for South America. Thus, the current review aimed to present the actual status of this problem in South America by summarizing and comparing the available data in the literature. An overview of the OTs concentrations in sediment and biota and their effects, mainly imposex in marine gastropods, are presented. This work showed that in Atlantic coastal areas of South America there are "hot spots" of OTs contamination, similar to that observed in industrialized countries of Northern Hemisphere. On the other hand, the number of accomplished studies in the Pacific coast is extremely low. Despite the limitation on studies about OTs environmental levels and their related effects, the available data pointed out for a widespread TBT contamination along the South American coastal areas. Therefore, the establishment of baselines of organotin contamination in the Pacific coast and the implementation of temporal trend studies in the South American coastal areas is crucial to verify the effectiveness of local regulations and OTs global ban, and to map the most sensitive areas related to present and future antifouling impacts.

Butyltin compounds and imposex levels in Ecuador

The first appraisal of butyltins (BT) contamination linked with imposex incidence in the Pacific coast of South America was performed in the current study. Imposex occurrence was analyzed in three muricid species (Thais biserialis, T. brevidentata, and T. kiosquiformis) distributed along 14 sites from the coastal areas of Ecuador. All studied muricids species showed imposex, which was observed in 11 out of 14 sites. The highest imposex levels were observed in T. kiosquiformis collected inside the Gulf of Guayaquil [relative penis length index (RPLI) 9.0-40.7], whereas RPLI values for T. biserialis and T. brevidentata ranged from 4.0 to 26.1 and 0.0 to 1.9, respectively. Additionally, BT compounds [tributyltin (TBT), dibutylin (DBT), and monobutylin (MBT)] were determined in surface sediments collected in 6 of the sites (main harbor areas), and values ranged between 12.7 and 99.5 ng Sn g(-1) (dry weight) for TBT, 1.8 and 54.4 ng Sn g(-1) for DBT, and 44 and 340 ng Sn g(-1) for MBT. Although BT degradation indexes suggested an aged input of TBT, the high imposex levels detected in the current study suggest that international restrictions on TBT based antifouling paints were still not effective in Ecuador. Considering that the southern coast, especially nearby harbors inside the Gulf of Guayaquil, have shown to be contaminated by BTs, a combination of T. kiosquiformis and T. biserialis (the most sensitive species) can be used for future biomonitoring of Ecuador coastal areas.