Organotins in fish, shrimp, and cephalopods from the Pearl River Estuary, China: Dietary exposure risk to Indo-Pacific humpback dolphin and human

Phenyltins may pose a higher health risk to Indo-Pacific finless porpoises than butyltins

Organotin (OT) compounds are commonly used in antifouling paints, but can cause toxic effects in various marine organisms, including gastropods, amphibians, and teleosts. The effects of these chemicals on marine mammals remain largely unknown. We comprehensively investigated the accumulation patterns and health risks of six OTs in Indo-Pacific finless porpoises (Neophocaena phocaenoides) from the Pearl River Estuary (PRE), China, from 2007 to 2020. Six OTs were detected in all the finless porpoise samples, with tributyltin (TPT) and dibutyltin (DBT) being the dominant chemicals in the liver and muscle, respectively. The mean hepatic concentration of TPT (516.1 ng g-1 wet weight) exceeded the levels reported for cetaceans from other regions. Despite the observed decreasing trends of butyltins (BTs) in recent years, which aligns with the global restriction of OT-based antifouling paints since 2008, phenyltins (PTs) have continued to increase in porpoise tissues, suggesting continued deposition of PTs in the PRE. In vitro, the tissue-relative concentrations of TPT, tributyltin, and DBT-induced lipid disruption by activating the finless porpoise peroxisome proliferator-activated receptor α/γ (npPPARα/γ). In silico simulations further revealed a higher toxic potential of PTs than BTs on npPPARα/γ. Our results underscore the urgency for further monitoring and elimination of PTs in China.

Positive impact of the legislation on organotins contamination in the marine environment of Hong Kong

Since September 2008, the use of organotin compounds (OTs) on antifouling systems on seagoing vessels has been globally banned by the International Maritime Organisation due to their toxic effects to non-target marine organisms. However, the regulation enforcement varies by government, hindering its effectiveness in controlling OTs contamination. For example, the Hong Kong Special Administrative Government enacted related legislation in January 2017. This study, conducted from 2022 to 2023, aimed to assess whether this law and its enforcement had significantly reduced OTs contamination in Hong Kong's marine environment. The results showed significant reductions in concentrations of butyltins (BTs) in seawater and total OTs in the rock shell Reishia clavigera from 2010 to 2023, though only dibutyltin (DBT) decreased in sediment. Triphenyltin (TPT) was identified as the predominant compound in all matrices, with levels correlating positively with shipping activities. Imposex levels in R. clavigera also significantly decreased, as indicated by the vas deferens sequence index and the proportion of sterile female compared to 2010 and 2015. A probabilistic risk assessment based on tissue burden of tributyltin (TBT) and TPT in R. clavigera suggested that current TBT levels no longer had significant adverse effects on the gastropod, while TPT could impact 68% of their populations. Over a five-year period since the legislation, substantial reductions in BTs in coastal waters, and overall OTs in rock shells were observed, but TPT persisted at concerning levels. Continued risk management measures and regular monitoring are crucial to further mitigate TPT contamination in Hong Kong waters.

Passive sampling-derived aqueous concentrations of organotins and booster biocides in the largest Port of South America (Southeastern Brazil)

Organotin compounds (OTs) used to be the most widely used biocide in antifouling paint systems, but the International Maritime Organization (IMO) banned them because of their high environmental toxicity to non-target organisms. Currently, at least 25 active ingredients are being employed as biocides in antifouling paint formulations. In the present study, silicone rubber-based passive sampling was used to determine the freely dissolved concentrations (Cw) of 6 OTs and 4 booster biocides in the water column at the entrance of Santos Port's main navigation channel, the largest Port of South America (southeastern Brazil). Fifteen sampling events of ∼45 days long were conducted over 2 years. Cw of OTs ranged from 1.1 to 2.5 ng Sn L-1 for monobutyltin (MBT), 0.2 to 4.7 ng Sn L-1 for dibutyltin (DBT), and 0.06 to 0.7 ng Sn L-1 for tributyltin (TBT), while triphenyltin (TPhT), diphenyltin (DPhT), and monophenyltin (MPhT) were always below their limits of detection ( Collapse

Key Words

• Aqueous phase
• Booster biocides
• Ecological risk
• Estuary
• Organotins
• Passive sampling

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MESH Headings

• Organotin Compounds/analysis
• Brazil
• Disinfectants/analysis
• Water Pollutants, Chemical/analysis
• Environmental Monitoring/methods
• Ships

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Affiliation(s)

Alan Carlos de Almeida Programa de Pós-Graduação em Química Tecnológica e Ambiental (PPGQTA), Universidade Federal do Rio Grande (FURG), Rio Grande, RS 96203-900, Brazil; Instituto de Oceanografia, Universidade Federal do Rio Grande (IO-FURG), Av. Itália s/n, Rio Grande, RS 96203-900, Brazil
Rodrigo Moço Batista Programa de Pós-Graduação em Química Tecnológica e Ambiental (PPGQTA), Universidade Federal do Rio Grande (FURG), Rio Grande, RS 96203-900, Brazil; Instituto de Oceanografia, Universidade Federal do Rio Grande (IO-FURG), Av. Itália s/n, Rio Grande, RS 96203-900, Brazil
Ítalo Braga Castro Universidade Federal de São Paulo, Instituto do Mar, Santos, SP 11030-400, Brazil
Gilberto Fillmann Programa de Pós-Graduação em Química Tecnológica e Ambiental (PPGQTA), Universidade Federal do Rio Grande (FURG), Rio Grande, RS 96203-900, Brazil; Instituto de Oceanografia, Universidade Federal do Rio Grande (IO-FURG), Av. Itália s/n, Rio Grande, RS 96203-900, Brazil.

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Imposex incidence in gastropod species from the Colombian Caribbean Coast reveals continued and widespread tributyltin contamination after its global ban

Organotin compounds (OTCs), such as tributyltin (TBT) and triphenyltin (TPhT), are released in aquatic environments from antifouling coatings and can cause imposex, an abnormal condition where female snails develop male sexual characteristics. This study investigates temporal variations in imposex incidence along the Colombian Caribbean coast following the 2008 global ban on TBT-based antifouling paints. Over a 12-year period, we assessed imposex in 1,384 adults snails from six species (58% female and 42% male) during 2012, 2016, and 2023. In 2012, just four years after the ban, imposex incidence in some sites reached 100% in the neogastropods Purpura patula, Stramonita haemastoma, Stramonita rustica, and Thais deltoideia. In 2016, imposex in some sites reached 81% for the mesogastropod Strombus pugilis and 39% for the neogastropod Melongena melongena. By 2023, imposex decreased for the first four neogastropods, persisted for S. pugilis, and increased for M. melongena only in Cartagena Bay and the Tolú marina. These findings indicate a general decline in imposex over time, aligning with the ban, but also suggest potential new sources of contamination as imposex rates increased in some previously unaffected areas.

Maternal exposure to tributyltin alters the breast milk, hormonal profile, and thyroid morphology of dams and induces sex-specific changes in neonate rat offspring

Tributyltin (TBT) is the chemical substance commonly used worldwide to prevent biofouling of vessels. Due to its ability to bioaccumulate and biomagnify, even after being banned, significant concentrations of TBT can be detected in sediment, affecting marine and human life. Although studies have shown that direct exposure to TBT alters physiological parameters in mammals, the relationship between exposure to TBT during pregnancy and lactation, considered critical windows for metabolic programming, has not been fully elucidated. Our hypothesis is that offspring whose mothers were exposed to TBT during critical stages of development may exhibit dysfunctions in endocrine-metabolic parameters. We used pregnant Wistar rats that were divided into groups and received the following treatments from gestational day 7 until the end of lactation by intragastric gavage: vehicle (ethanol 0.01%; Control), low TBT dose (100 ng/kg of body weight (bw)/day; TBT100ng) and high TBT dose (1000 ng/kg bw/day; TBT1000ng). Dams and offspring at birth and weaning (21 days old) were studied. Maternal exposure to TBT promoted dose-dependent changes in dams. The findings for adiposity, milk composition and lipid profile were more pronounced in TBT100 ng dam; however, thyroid morphology was altered in TBT1000 ng dam. Female offspring were differentially affected by the dose of exposure. At birth, females in the TBT100ng group had low body weight, lower naso-anal length (NAL), and higher plasma T4, and at weaning, females in the TBT100ng group had lower insulin and leptin levels. Females in the TBT1000ng group had lower NAL at birth and lower leptinemia and weight of white adipose tissue at weaning. Male offspring from TBT groups showed high T3 at birth, without biometric alterations at birth or weaning. Despite these findings, both sexes exhibited dose-dependent morphological changes in the thyroid gland. Thus, maternal exposure to TBT constitutes an important route of contamination for both dams and offspring.

Organohalogen contaminants threaten the survival of indo-pacific humpback dolphin calves in their largest habitat

As long-lived apex predators, marine mammal adults often accumulate alarmingly levels of environmental contaminants. Nevertheless, the accumulation and risks of these contaminants in the critical calf stage of marine mammals remain largely unknown. Here, we investigated the exposure status and health risks of 74 organohalogen contaminants (OHCs) in Indo-Pacific humpback dolphin calves (Sousa chinensis) collected from the Pearl River Estuary (PRE), China, during 2005-2019. Our findings revealed moderate levels of polychlorinated biphenyls (PCBs), medium-high levels of dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs), and the highest levels of polybrominated diphenyl ethers (PBDEs) and alternative halogenated flame retardants (AHFRs) compared to those reported for cetaceans elsewhere. Traditional OHCs like DDTs, PCBs, and PBDEs did not exhibit significant decreasing trends in the dolphin calves despite global restrictions on these compounds, and AHFRs as emerging OHCs showed an increasing trend over the study period. Risk quotients of DDTs, HCHs, PBDEs, and PCBs in most of the dolphin samples were > 1, indicating that humpback dolphin calves may have suffered long-term threats from OHC exposure. The significant correlation observed between the traditional OHC levels and the stranding death number of the dolphin calves suggests these OHCs may impact the survival of this endangered species.

Factors affecting the accumulation of organotins by wild fish: A case study in the Three Gorges Reservoir, China

Organotin compounds (OTs) accumulate in fish easily, however, research on their influencing factors is still limited. This study collected 25 species of fish with different diets, habitats, and age from the Three Gorges Reservoir (TGR), the largest deep-water river channel-type reservoir in China, and analyzed the accumulation characteristics of OTs in these fish. The results showed that tributyltin (TBT) and triphenyltin (TPhT) were the dominant OTs in fish from the TGR. The correlation between OTs concentration and age, body length, and body weight varied with fish species. The concentrations of TBT and TPhT in carnivorous fish (mean, 25.78 and 11.69 ng Sn/g dw, respectively) were higher than those in other diet fish (P<0.01), but there was no significant difference in fish at different habitat water layers (P>0.05). In addition, the degradation rates of TBT and TPhT in different fish species were all below 50%. In summary, the accumulation of TBT and TPhT in fish is mainly influenced by diet, and both TBT and TPhT were difficult to degrade in fish. These results reveal the pollution characteristics of OTs in fish from the TGR, and can improve our understanding of the factors influencing TBT and TPhT accumulation in freshwater fish.