Hindsight check: LL2-12 (Part B divider and Ch 12 Booster biocide antifoulants: is history repeating itself?)#

Source section: EEA, Late lessons from early warnings: science, precaution, innovation (EEA Report No 1/2013), pp. 261–278. Pages 261–264 are the Part B divider, contents and panel list. Chapter 12 (pp. 265–278) is by Andrew R. G. Price and James W. Readman. Check window: publication (2013) to late September 2026. Checked: 25 September 2026.

Method note. - General web search was unavailable for this pass because the session’s search budget was exhausted. I retrieved sources by fetching primary repositories directly: - the EU Publications Office (its SPARQL metadata endpoint and the Official Journal texts in its document store), for EU biocide decisions and water legislation from 2021 onward; - legislation.gov.uk, which republishes EU legislation adopted up to 31 December 2020 (used for the 2007–2017 biocide acts); - the IMO website, including its Status of Treaties spreadsheet (as at 25 August 2026); - the Stockholm Convention clearing house (the DDT register); - Europe PMC and Crossref, for peer-reviewed abstracts, and open-access full text where available; - the EEA website and the website of one coatings manufacturer (Jotun). - Access limits. - EUR-Lex refused automated requests (HTTP 202 with an empty body) and ECHA returned 403. I therefore read EU acts through the Publications Office and legislation.gov.uk, and cite them by their ELI or legislation.gov.uk address. I could not read ECHA’s committee opinions directly. I rely on the Commission’s own summaries of them in the recitals of its decisions. - Where a point rests only on an abstract or on bibliographic metadata, I say so. - Scope. I read only the section digest, the section’s source extract and web sources. Page numbers are report pages of the 2013 volume. - Annex 3. Booster biocides are a new case in the 2013 volume, so there is no Annex 3 update for it. The chapter’s TBT background draws on the 2001 TBT chapter (Santillo et al., cited p. 267), which Annex 3 may update. The task limits me to the files named, so I did not open Annex 3. My TBT findings (Claim 9) come from outside sources. - Part B divider. Pages 261–264 carry no argument, only titles and lists, so there is nothing there to check. Part B’s framing sits in the report’s general introduction, which is outside this section. - Author position. Readman made the first Irgarol detection (1993) and the Bermuda measurements, and 13 of the chapter’s 41 references are the authors’ own work. I found only two post-2013 papers by either author on related topics [S62, S63], and neither revisits the chapter’s claims. So the later evidence below is independent of the authors.

Overview#

The chapter makes three kinds of claim. Thirteen years on, they have fared differently.

1. The central warning has been borne out, more strongly than the chapter could show. Its warning was that substitutes for a banned hazard inherit an assumption of safety and then turn out to carry their own risks. - Regulators confirmed the lead case. - The EU refused to approve cybutryne (Irgarol 1051) for antifouling in January 2016, because the environmental risk assessment “identified unacceptable risks” [S1]. - The EU made cybutryne a Water Framework Directive (WFD) priority substance in 2013, with an annual-average quality standard of 2.5 ng/L [S4]. The 2026 revision of the Directive kept that standard unchanged [S5]. - The IMO banned new applications worldwide from 1 January 2023. It cited “significant adverse effects to the environment, especially to aquatic ecosystems” [S2, S3]. - Diuron. It had already dropped out of the EU’s antifouling review by 2007, which meant diuron antifoulings could no longer be placed on the EU market [S36]. Its EU quality standard for coastal waters is being tightened about 40-fold, from 200 to 4.9 ng/L, with effect from December 2027 [S4, S5]. - Corals. A 2023 systematic review of coral toxicity data found that regulatory reference values protect corals for all assessed chemicals except three: copper, diuron and Irgarol [S6].

2. The substitution cycle repeated one step further. The “almost uninvestigated” novel agents the chapter named (p. 276) were evaluated and approved in 2014–2015. - Medetomidine was approved in 2015 but was already flagged as “very persistent” and “toxic” and designated a candidate for substitution [S22]. In 2024 ECHA’s Biocidal Products Committee concluded that it has endocrine-disrupting properties that may harm humans, which meets an exclusion criterion under the EU Biocidal Products Regulation. As of 20 May 2026 its renewal was still undecided, and its approval runs to 31 December 2026 [S23, S24]. - DCOIT (Sea-Nine 211). Its renewal as a wood preservative was delayed in 2025 “due to the need for additional time to complete the assessment of endocrine-disrupting properties”, and its antifouling approval now runs to 30 June 2028 [S21]. - Tralopyril (Econea). A 2026 independent test of seven leisure-boat coatings found the one tralopyril product the most toxic and highest-risk of the set, although it was marketed as “environmentally safe” [S27].

3. The chapter’s reassurance on endocrine disruption has weakened (pp. 265, 270, 275). No booster biocide has been shown to cause TBT-like masculinisation (imposex) of female snails in the field. But the broader claim that the boosters “do not threaten to have endocrine disrupting properties” no longer holds for at least two current substitutes, medetomidine and DCOIT [S17–S21, S23, S24].

4. Some parts of the chapter were overstated or already out of date. - Effectiveness. The claim that bans in Bermuda and the UK “limited adverse ecological impacts” (p. 276) still has no ecological outcome data behind it. I found no post-ban Bermuda concentration data. - Concentrations. The UK reduction the chapter reports was measured against a “proposed” standard of 24 ng/L. That is about ten times the 2.5 ng/L standard the EU adopted in 2013. Later English and wider European data show residues that often exceed 2.5 ng/L [S11, S13, S14]. - A research gap that had already closed. The chapter says the interaction between herbicides and warm-water bleaching “has not yet been tested” (p. 270). A 2011 study had already tested it and found additive and, for chronic photoinhibition, synergistic effects [S30]. - Regulatory timing. The EU decisions described as “expected shortly” in 2008 (Table 12.3, p. 272) arrived between 2014 and 2017. The EU’s review of existing biocidal substances has since been extended to 2030 [S38].

5. The innovation diagnosis has only partly held up. - What held. Biocide-free non-stick (“foul-release”) coatings did not become the norm. Biocidal coatings still reportedly account for more than 90% of sales (a 2021 paper citing 2012 and 2018 sources) [S50]. - What changed. The technology did advance. Independent trials now find silicone foul-release coatings as effective as copper or better, even on stationary panels [S48, S49]. - Incumbents. A major incumbent paint maker, working with partners, developed the robotic “proactive cleaning” the chapter mentions (p. 275). It paired the robot with its own self-polishing silyl-acrylate coating, which I infer is biocidal [S52, S53]. So the claim that only outsiders innovate beyond “more biocide” is weakened. - New questions about the alternatives. - Foul-release coatings rely on fluorinated and organosilicon chemistry that a 2026 study prioritised for environmental monitoring [S54]. - Discharges from robotic in-water cleaning are toxic to fish embryos and plankton [S55, S56].

Fair reading. As an early-warning account, the chapter is reliable: its main hazard claims and its “history repeating” thesis were vindicated and extended after 2013. Its success claims should carry little weight. The pattern of later events is regulatory confirmation that took two to three decades, followed by a new round of substitutes whose problems emerged within about a decade of approval. That fits the chapter’s thesis better than its own conclusion that “policy has proven effective” (p. 276).

Claim-by-claim#

Claim 1: Booster biocides “threaten a variety of habitats — from coral reefs and seagrass beds to open moorings — within the EU and globally”; coral zooxanthellae, phytoplankton and periphyton are “particularly vulnerable”, and the base of marine food chains may be affected (pp. 265, 276)#

Original claim. - The claim appears in the chapter summary (p. 265) and again in the conclusions (p. 276). - Its evidence base is laboratory and microcosm effects plus harbour concentrations. These include phytoplankton EC50s around 70 ng/L and inhibition of coral-symbiont photosynthesis down to 60 ng/L (p. 270). The EC50 is the concentration that halves the measured response, such as growth or photosynthesis. - The authors’ own Chagos study found “negligible risks” at that remote site (p. 277, reference list).

Subsequent developments - Regulatory findings on Irgarol/cybutryne. - EU. Commission Implementing Decision (EU) 2016/107 of 27 January 2016 refused approval of cybutryne for product type 21 (antifouling products). ECHA’s Biocidal Products Committee gave its opinion on 17 June 2015. According to that opinion, cybutryne products “may not be expected to satisfy the requirements… The scenarios evaluated in the environmental risk assessment identified unacceptable risks” [S1]. - WFD. Directive 2013/39/EU listed cybutryne as priority substance 40. It set an annual-average quality standard (AA-EQS) of 0.0025 μg/L (2.5 ng/L) and a maximum allowable concentration (MAC-EQS) of 0.016 μg/L (16 ng/L) for both inland and other surface waters [S4]. Directive (EU) 2026/805 (30 March 2026) retained both values unchanged [S5]. - IMO. In July 2017 the IMO’s Marine Environment Protection Committee (MEPC 71) opened work to add cybutryne to the Anti-Fouling Systems (AFS) Convention “as scientific data indicated that cybutryne causes significant adverse effects to the environment, especially to aquatic ecosystems”. The amendments were adopted in June 2021 and entered into force on 1 January 2023 [S2, S3]. - Diuron. - Out of the EU review. Annex II of Regulation (EC) No 1451/2007 lists diuron in the review programme for product types 6, 7 and 10 only, not type 21 (antifouling). Under Article 4(1) of that Regulation, products containing a listed substance “shall no longer be placed on the market” for product types not listed [S36]. Delegated Regulation 1062/2014 again lists diuron for types 7 and 10 only [S37]. On the legal text, diuron antifoulings therefore had to leave the EU market by 2007 at the latest, because diuron was not in the review programme for that use, not because of a finding of unacceptable risk. (Presumably no company defended an antifouling dossier, but I did not verify this.) I could not load the earlier 2003 Regulation, so the exact earlier date is unconfirmed. - Tighter standard. Directive (EU) 2026/805 revises diuron’s quality standard for “other surface waters” (transitional and coastal) from an AA-EQS of 0.2 μg/L to 0.0049 μg/L, and its MAC-EQS from 1.8 to 0.054 μg/L. The revised values take effect on 22 December 2027, with good status required by 22 December 2033 [S4, S5]. - Coral and symbiont evidence. - Systematic review. Ouédraogo et al. (2023) reviewed 181 articles of coral toxicity tests. Comparing the toxicity thresholds with regulators’ reference values, they found the reference values “appear to be protective of corals for all but three chemicals assessed: the metal copper and the pesticides diuron and irgarol 1051” [S6]. - Near-ambient effects. Kamei et al. (2020) exposed the coral Acropora tenuis to Irgarol at 20 and 200 ng/L for 7 days. - Symbiont photosynthetic efficiency fell by 8% at 20 ng/L and by 37% at 200 ng/L. - Heat-shock proteins in the symbionts were upregulated at both concentrations. - Coral colour did not change. - The authors put the threshold below 20 ng/L, “around ecologically relevant concentrations in tropical to subtropical waters” [S7]. - Symbiont thresholds. Marzonie et al. (2021) found that all seven photosystem II herbicides tested inhibited the growth and photosynthesis of cultured coral symbionts [S33]. The study concerns agricultural herbicides relevant to the Great Barrier Reef, not antifoulants specifically. - Field concentrations near reefs and in harbours after 2013. - Zanzibar. Irgarol at 1.35–15.44 ng/L (mean 4.11 ng/L). The authors judged this “not alarming” against the Dutch 24 ng/L limit [S8], but the mean exceeds the EU AA-EQS of 2.5 ng/L. - Panama. Irgarol up to 5.0 ng/L and diuron up to 70 ng/L, both below the UK standards [S9]. - Western Mediterranean ports (Italy, France). Irgarol at 0.9–59.8 ng/L by passive sampler [S13]. - French Mediterranean lagoons (2015–16). Irgarol and diuron were among the few substances driving potential chronic risk to phytoplankton, crustaceans and fish [S10]. - Brazilian ports (2026 study). Diuron at 0.30–7.39 μg/L and Irgarol at 1.98–5.70 μg/L. These are μg/L, orders of magnitude above the European ranges above. They were measured with a method whose quantification limit for Irgarol was 0.5 μg/L, and the authors’ risk assessment indicated likely adverse effects on sensitive species [S58]. This supports “globally” and the chapter’s point about uneven regulation (p. 265). - Malaysian seagrass estuary (2026 study). Irgarol and its breakdown product M1 were detected in seagrass roots and fish tissues [S43].

Complications - I found no post-2013 study that attributes observed field damage to reefs, seagrass or plankton communities specifically to booster biocides. The harm remains shown mainly in laboratory and mesocosm studies, at or near measured field concentrations. - The chapter’s own reference site, Chagos, showed negligible risk. Reef-adjacent concentrations elsewhere are mostly single-digit ng/L. - For corals, copper is now as much a concern as the organic boosters [S6]. The chapter left copper in the background.

Verdict: strengthened (as a hazard claim). EU and IMO regulators and a systematic review now support the claim of particular vulnerability for cybutryne and diuron. Field-level ecological damage remains largely undemonstrated, which is consistent with the chapter’s cautious “threaten” wording.

Implications for weight. The hazard lesson carries substantial weight: a substitute that works by inhibiting photosynthesis puts the whole primary-producer base at risk. Treat claims of realised ecological damage as still unproven. The lesson is about foreseeable hazard and the cost of waiting, not documented collapse.

Claim 2: Booster biocides “do not threaten to have endocrine disrupting properties similar to TBTs” (p. 265); “significant endocrine disruption… was not found for booster biocides (ACE, 2002)” (p. 275), based on an EU ACE-project screen in which none of seven antifoulants “showed a strong estrogenic response” (p. 270)#

Original claim. The reassurance rests on one screen for oestrogenic activity. That screen covered Irgarol 1051, Sea-Nine (DCOIT), chlorothalonil, diuron, dichlofluanid, maneb and ziram (p. 270).

Subsequent developments - DCOIT (Sea-Nine 211), one of the screened agents. - Chen et al. (2014). Adult marine medaka exposed for 28 days showed: - raised oestradiol and lowered testosterone in males; - fewer eggs and impaired reproductive success. The authors called DCOIT “a potent endocrine disruptive chemical” [S17]. - Chen et al. (2016). They located the mechanism in the hypothalamus–pituitary–gonad–liver hormone axis: DCOIT stimulated steroid-hormone synthesis in both sexes. Exposure concentrations were 0.76–9.86 μg/L, and effects were passed to offspring [S18]. A hormone-synthesis mechanism of this kind is one a receptor-binding oestrogen screen would not be designed to detect. - Liu et al. (2024). They reported disruption of the thyroid axis, including binding to the thyroid hormone receptor β, at “environmentally realistic concentrations” [S20]. - Chen & Lam (2017, review). DCOIT’s degradation half-life varies from under 1 day to 13.1 days, and it has been measured at up to 3,700 ng/L in Spanish seawater. Its “endocrine disrupting and reproductive impairing effects… constitute a long-term threat” [S19]. - Regulatory response. In 2025 the Commission postponed the expiry of DCOIT’s approvals to 30 June 2028. For its use as a wood preservative (product type 8), the evaluating authority (Norway) reported delay “due to the need for additional time to complete the assessment of endocrine-disrupting properties”. Its report to ECHA is expected in 2027 [S21]. - Medetomidine, a post-2010 substitute the chapter flagged. ECHA’s Biocidal Products Committee adopted an opinion on 28 May 2024. According to the Commission, the opinion considers medetomidine to have “endocrine-disrupting properties that may cause adverse effects in humans”, which “meets the exclusion criterion” of Article 5(1)(d) of the Biocidal Products Regulation. Renewal was still under discussion on 20 May 2026, and the approval runs to 31 December 2026 [S23, S24]. - Other agents. - Tralopyril raised thyroid hormone levels and altered thyroid-related gene expression in medaka [S28]. - Diuron altered gonad histology in Javanese medaka in a 21-day study using 1–1,000 μg/L [S60b]. - Diuron also showed thyroid-related effects in zebrafish larvae, but only at 0.6 mg/L and above [S60]. These are laboratory findings at concentrations mostly well above ambient levels.

Complications - No booster biocide has been reported to cause imposex in snails or anything comparable to TBT’s field-scale endocrine effects at ng/L. On the narrow reading, “similar to TBTs”, the claim still stands. - Most fish endocrine effects of DCOIT were reported at μg/L. Typical coastal concentrations are ng/L, although hotspots reach μg/L [S19]. - The research group behind the 2014 medaka study was developing butenolide, a competing antifoulant, which that study compared favourably with DCOIT [S17]. This is a potential interest, though later studies by other groups also found thyroid effects [S20, S28]. - The medetomidine finding concerns human health endocrine disruption under the Regulation’s criteria, not wildlife.

Verdict: weakened. The narrow claim, no TBT-like imposex, survives. The general reassurance does not: regulators now treat one current antifoulant as meeting endocrine-disruptor exclusion criteria and are still assessing another. The original evidence, an oestrogen screen alone, could not have supported so broad a statement.

Implications for weight. Give the chapter’s endocrine reassurance little weight. It illustrates a general pattern: a clean result on a narrow screen can be read as a clean bill of health, and the screen chosen reflects the last hazard rather than the next one.

Claim 3: The UK’s 2001 restriction of small-vessel antifoulings to dichlofluanid, zinc pyrithione and zineb cut Irgarol 1051 concentrations “to below the proposed Environmental Quality Standard, EQS, of 24 ng/L”, and simple manufacturer-level regulation worked despite continued retail sales (p. 273). The chapter’s “by 10–55 %” misstates the source.#

Original claim (p. 273). The chapter summarises Cresswell et al. (2006). It reports a “clear reduction in water concentrations of Irgarol 1051 (by 10–55 % of levels in pre‑restriction studies)”.

Subsequent developments - The misstatement is confirmed. Cresswell et al.’s abstract says concentrations were “between 10% and 55% of that found during pre-restriction studies” [S15]. That is a reduction of 45–90%, larger than “by 10–55%” implies. - A further decline, but residues above today’s standard. Zhou (2008) sampled coastal waters of southern England in 2004–2005 [S14]. - Irgarol averaged 13 ng/L (maximum 89 ng/L) in water and 16 ng/g in sediment, and was still declining. - Paint residues and organic-rich sediments act as long-term stores, releasing Irgarol with a half-life of about a year. The 2004–2005 mean is about five times the EU’s 2013 AA-EQS of 2.5 ng/L. Spot samples are not strictly comparable with an annual-average standard, but the gap is large. - Paint particles keep leaching. Hasan et al. (2014) found that Irgarol continued to leach from spent paint particles collected at a Plymouth marina for 10 days, reaching 0.61 μg/L [S16]. - Later UK data. I found no published post-2013 time series for Irgarol or cybutryne in UK waters. - Wider Europe after 2013. - Germany. A survey of 50 marinas found cybutryne above the WFD maximum allowable concentration (16 ng/L) at 5 of them [S11]. - Denmark (13 marinas). Irgarol was found in all sediment samples and half of water samples. Concentrations were lower than in earlier monitoring, a decrease the authors attribute to legislation and the 2016 non-approval [S12]. - Western Mediterranean ports. Up to 59.8 ng/L [S13]. - The benchmark was too lenient. The “proposed EQS” of 24 ng/L was about ten times the standard the EU adopted in 2013 [S4].

Verdict: partly held up. Manufacturer-level restriction did cut concentrations substantially, by more than the chapter’s wording conveys. But the success was measured against a lenient provisional benchmark. Residues from legacy paint, sediments and paint particles persisted above the later EU standard. EU-wide non-approval (2016) and the IMO ban (2023) were needed to close the remaining routes.

Implications for weight. - The narrow lesson holds: simple controls at the supply choke point work quickly, even with weak retail enforcement (p. 273; [S12, S14, S15]). - It needs two qualifiers: - “success” depends heavily on which threshold is used, and early thresholds tend to be lenient; - persistent legacy stocks in sediments and paint debris keep releasing the substance long after supply stops.

Claim 4: “Policy has proven effective in, for example, Bermuda and the United Kingdom, where banning selected agents lowered concentrations and limited adverse ecological impacts” (p. 276; Box 12.2, p. 271)#

Original claim. Bermuda banned Irgarol- and diuron-based paints on 1 July 2005, after locally funded coral toxicology (Box 12.2, p. 271). The chapter presents no post-ban Bermuda data. For the UK its evidence is concentrations only (p. 273).

Subsequent developments - Bermuda. I searched Europe PMC and Crossref (web search was unavailable) and found no post-2005 measurements of Irgarol or diuron in Bermuda, and no coral outcome study attributing change to the ban. - The only post-2013 Bermuda antifouling study I found concerns paint particles from boatyard maintenance, a different route. Adding such particles at 0.3 g/L killed all copepods within 88 hours and raised dissolved copper [S57]. This shows that copper-based paint waste remains a local problem. - I could not retrieve the text of Bermuda’s regulations to confirm whether the 2005 ban is still in force. - UK. There are no ecological outcome data. Concentration evidence is summarised under Claim 3. - Elsewhere. Declines in Irgarol concentrations after restrictions have been reported for Denmark [S12] and southern England [S14]. I found no ecological outcome evaluation of any booster-biocide ban.

Verdict: unclear. The claim that the bans “limited adverse ecological impacts” has neither been supported nor refuted. The concentration half is supported for the UK and has no published data for Bermuda.

Implications for weight. - Give this success claim little weight. - More broadly, where harm was mainly potential, “effectiveness” can only be shown by exposure falling. An ecological benefit is then inferred, not observed. - The Bermuda example still supports a narrower lesson: a small jurisdiction that funded its own evidence acted faster than harmonised regimes, banning the two biocides in 2005, about a decade after Readman’s 1995 measurements (pp. 271–272). The EU did not act on cybutryne until 2016.

Claim 5: “The notion that Irgarol and diuron contamination could exacerbate bleaching caused by elevated water temperatures has not yet been tested” (p. 270)#

Original claim (p. 270). Herbicides and warm water may both cause bleaching through effects on symbiont photosynthesis (citing Jones, 2005). Their interaction is said to be untested.

Subsequent developments - Already tested before publication. Negri et al. (2011, Limnology and Oceanography) exposed the coral Acropora millepora to diuron and two other photosystem II herbicides at 26–32 °C [S30]. - “Environmentally relevant concentrations of each herbicide increased the negative effects of thermal stress on coral at 31°C and 32°C.” - Effects on photosynthetic efficiency were additive. Effects on chronic photoinhibition were “distinctly greater than additive (synergistic)” for diuron and atrazine. - Reducing diuron by 1 μg/L above 30 °C would protect photosynthetic efficiency by the equivalent of a 1.8 °C temperature reduction. - The chapter’s reference list ends around 2010 and does not cite this paper. - Built into guideline-setting. Negri et al. (2020) developed a way to adjust water quality guideline values for heatwaves, using diuron and copper as reference toxicants [S31]. They combined toxicity data for many species into an estimated fraction of species affected, and treated heat as an additional stressor. - Tested for Irgarol. Gushi et al. (2025) exposed an Acropora species to Irgarol at 1.0 μg/L. At 30 and 32 °C they found a “significant interactive decrease” in symbiont photosynthetic efficiency on day 1: heat stress accelerated the early response to Irgarol [S32]. The dose (1 μg/L) is well above the 60–250 ng/L effect concentrations the chapter cites (p. 270), and the authors note that responses differ between genotypes. - Seagrass. A 2019 study of eelgrass examined herbicide, low light and high temperature together [S64] (title only).

Complications. - Most of this work uses agricultural photosystem II herbicides, or diuron from all sources, not antifouling releases specifically. - The Irgarol result comes from a single species at a high dose.

Verdict: strengthened. The hypothesis the chapter flagged has been supported: herbicide and heat stress add together, and for some endpoints the combined effect is greater than the sum. But the statement that it was “not yet tested” was already out of date when the chapter was published.

Implications for weight. - The underlying lesson carries weight: a local contaminant can reduce resilience to a global stressor, and single-stressor thresholds may not protect under warming. - The episode is also a caution about the section’s currency. Its evidence base largely stops around 2010, so its statements of knowledge gaps need checking.

Claim 6: Novel antifoulants (“phenylborane pyridine, Econea, capsaicin and medetomidine”) “are almost uninvestigated, with very little information available on them in the public domain” (p. 276; also p. 267)#

Original claim. The chapter flags these newly introduced compounds as the next wave (p. 267) and warns that they are largely unassessed in public (p. 276).

Subsequent developments - EU evaluation and approval. - Tralopyril (the active ingredient of Econea). - The UK received the application in July 2007 and sent its assessment report in September 2009. ECHA’s committee gave its opinion in April 2014. - Tralopyril was approved by Implementing Regulation (EU) No 1091/2014, from 1 April 2015 to 31 March 2025 [S25]. - A renewal application followed in September 2023, and in November 2024 the expiry was postponed to 30 September 2027 [S26]. - Medetomidine. Implementing Regulation (EU) 2015/1731 approved it from 1 January 2016 to 31 December 2022 [S22]. - The approval states that medetomidine is “very persistent (vP) and toxic (T)”, contains “a significant proportion of non-active isomers or impurities”, and “should… be considered a candidate for substitution”. - It requires application and maintenance in contained areas “to prevent direct losses and minimise emissions” [S22]. - Renewal has since been postponed three times: to 30 June 2025, then 30 June 2026, then 31 December 2026. The first postponement (2022) allowed time for the evaluation; the later two followed ECHA’s 2024 endocrine-disruption finding (Claim 2) [S23, S24]. - Triphenylborane pyridine and capsaicin. Neither is among the product-type 21 substances in the EU review programme (Delegated Regulation 1062/2014, Annex II) [S37]. I found no EU approval act for either, so they are not permitted in EU antifoulings. A 2018 review derived hazard-based environmental quality standards for both, alongside other boosters [S29]. - Other approvals. - zineb (2014); - DCOIT (2014, from 1 January 2016); - tolylfluanid (2015); - copper pyrithione (2015); - dicopper oxide, copper thiocyanate and copper flakes (2016); - dichlofluanid (2017, from 1 November 2018) [S34, S35]. - Later evidence of harm or risk. - Tralopyril. Lagerström et al. (2026) tested seven commercial leisure-boat coatings at three European sites. The tralopyril coating, “despite being marketed as ‘environmentally safe’, demonstrated the highest toxicity and environmental risk”. A biocide-free silicone coating ranked most sustainable [S27]. Laboratory studies in marine medaka report damage to several organs and thyroid disruption [S28]. - Medetomidine. Endocrine-disrupting properties in humans, as above [S23, S24]. - Monitoring. A 2020 survey of 13 Danish marinas did not detect medetomidine, tralopyril or DCOIT in any sample [S12]. This may reflect low use, rapid degradation, or the difficulty of measuring these compounds (the abstract does not give detection limits).

Verdict: strengthened. The chapter was right that the next generation was largely unassessed in public. Their later evaluation partly repeated the cycle the chapter warns about: - one agent was approved while already flagged as a candidate for substitution, then found to meet an endocrine-disruptor exclusion criterion; - another, sold as benign, performed worst on toxicity in independent testing.

Implications for weight. - The “history repeating” thesis is supported beyond the chapter’s own evidence. - The EU system did not simply wave these agents through. It attached substitution status and conditions, and it reassessed them at renewal. That is precaution partly working. - It still let a “candidate for substitution” substance remain on the market for more than ten years (2016 to at least end-2026) while its problems were confirmed.

Claim 7: Non-stick (fluoropolymer or silicone) coatings show “modest performance”; with expense, poor adhesion and damage susceptibility, “widespread commercial application seems unlikely without further advances in technology”. Incumbent manufacturers “tend to devise solutions with which they are familiar — typically more biocide”, while “companies that could develop more innovative solutions are generally unaware of the emerging market” (p. 275)#

Original claim (p. 275). It draws on Readman (2006). It also mentions “polishing robots” as a relatively undeveloped alternative.

Subsequent developments - Performance has advanced. - Baltic Sea. Lagerström et al. (2022) exposed panels for a year at three sites. The biocide-free foul-release coating “was found to perform equally well or significantly better than the copper coatings”. The authors call for its use to be promoted [S48]. - Five European sites. Adouane et al. (2026) exposed panels statically for seven months. Foul-release coatings “consistently outperformed copper-based coatings”, and their leachates were about 100 times less toxic to a red alga [S49]. - Leisure-boat ranking. Lagerström et al. (2026) ranked a biocide-free silicone coating highest on sustainability [S27]. - Uptake remains limited. - Papadatou et al. (2021) report that biocidal coatings “still dominate the market reportedly accounting for more than 90% of coatings sales”. They cite sources from 2012 and 2018 [S50]. - A 2020 news feature in ACS Central Science (secondary source) says foul-release coatings are “readily commercially available today but have not been widely adopted”. The barriers it gives are switching costs (stripping to bare metal) and poor performance on stationary vessels [S51]. - I found no primary market-share figure for 2020–2026. - Robots came from an incumbent, with partners. - Jotun’s system. Jotun, a leading marine-paint maker, markets “Hull Skating Solutions”, developed “jointly by Jotun and its partners through exclusive co-operation agreements” with Kongsberg Maritime, Wallenius Wilhelmsen and DNV. Its “HullSkater” robot is described as “the first robotic device that has been purposely designed for proactive cleaning” [S52]. - Paired with a conventional antifouling coating. The system uses a dedicated coating, SeaQuantum Skate, built on Jotun’s silyl-acrylate technology [S52]. The page does not state the coating’s biocide content. Silyl-acrylate antifoulings are, in general, self-polishing coatings that release biocide as they wear, so I treat it as biocidal (my inference). - Uptake. In August 2026 Carnival Cruise Line signed up as the first cruise operator [S53]. - Independent research. Studies on “grooming” (proactive in-water cleaning) continue, including US Navy-related trials [S61]. - New questions about the alternatives. - Chemistry of foul-release coatings. Lastoria et al. (2026) catalogued 3,075 substances used in marine coatings and prioritised 59 for monitoring, 33 of them fluorinated and 12 organosilicon. They note a trend towards “perfluorinated and organosilicon substances as the basis of fouling-release compositions” [S54]. - Not biologically neutral. Adouane et al. (2026) conclude that “biocide-free does not mean biologically neutral”, because foul-release leachates also altered microbial behaviour [S49]. Lagerström et al. (2022) likewise note that leachables from silicone foul-release coatings “may not be completely environmentally benign” [S48]. - Cleaning discharges. Discharge from robotic in-water cleaning caused developmental malformations in flounder embryos, with zinc pyrithione the dominant biocide [S55]. Cleaning wastewater cut phytoplankton and zooplankton in mesocosms [S56]. These studies concern cleaning of biocidal hulls.

Verdict: partly held up. The prediction that biocide-free coatings would not reach widespread use without technical advances fits the persistent more-than-90% biocidal share. But the technology did advance, so that cause now explains less; switching costs and suitability for stationary vessels now look like the main barriers. The incumbent-versus-outsider thesis is weakened: a major incumbent led robotic proactive cleaning, although it paired the robot with its own self-polishing coating (biocidal, by inference).

Implications for weight. - The insight that incumbents innovate within their existing competence has some support: the flagship robotic system keeps the maker’s own self-polishing (by inference, biocidal) coating at its core. - But treat “radical alternatives come from outsiders” as asserted, not shown. - The later record adds a caution the chapter did not raise. “Non-toxic” alternatives bring chemistries of their own, fluorinated and organosilicon compounds among them, that need assessment before the next substitution.

Claim 8: Recommendation to continue Europe-wide monitoring of banned and permitted antifoulants, as a scaled-down version of the ACE project, starting with Irgarol, using Chagos as a clean reference, and “firmly linked to an action plan” with “predetermined threshold level(s)” so that monitoring does not become “an essentially scientific or academic pursuit” (p. 274)#

Subsequent developments - WFD monitoring with legal thresholds, adopted in 2013. Directive 2013/39/EU made cybutryne a priority substance with legally binding quality standards [S4]. For it and other newly listed substances, Member States had to: - establish “a supplementary monitoring programme and a preliminary programme of measures” by 22 December 2018; - aim for good chemical status by 22 December 2027. This is close to the chapter’s “predetermined threshold” linked to action, though implemented through river-basin programmes of measures rather than a dedicated antifouling indicator. - Retained and extended in 2026. Directive (EU) 2026/805 kept cybutryne’s standards and tightened diuron’s coastal standard about 40-fold [S5]. - Dedicated indicator. I found no evidence that a dedicated Europe-wide booster-biocide indicator of the kind Price and Readman (2006) proposed was adopted, nor any continued use of Chagos as a benchmark. The EEA’s Europe’s state of water 2024 reports chemical status in aggregate: 29% of surface water bodies achieved good chemical status in 2021 [S59]. I found no cybutryne-specific EU compliance figures. - Monitoring by researchers continues. Most post-2013 data come from academic or national one-off surveys (Germany, Denmark, the western Mediterranean, French lagoons) [S10–S13], not a harmonised programme. Studies still note gaps for the newer agents [S12, S29].

Verdict: partly held up. The core of the recommendation, monitoring tied to binding thresholds, was adopted for cybutryne (and diuron) through the WFD. The specific design, a pan-European antifouling indicator with a pristine reference site, was not. Whether the WFD thresholds will trigger effective action will only be testable after the 2027 deadline.

Implications for weight. - The insight that monitoring without action thresholds drifts into an academic exercise remains asserted, not tested. The post-2013 landscape does partly illustrate it: much of the evidence comes from one-off academic surveys. - Regulators did adopt threshold-linked monitoring, but with long lead times: listed in 2013, monitoring programmes by 2018, good status due by 2027.

Claim 9: TBT “levels are still going up in Asia” despite bans (p. 267), and “even today DDT is used in China as an antifoulant” (p. 276, citing Thomas and Brooks, 2010)#

Subsequent developments - The AFS Convention. In force since 17 September 2008 [S2]. As at 25 August 2026, parties include China (with Hong Kong and Macao listed separately), Japan, the Republic of Korea, India, Indonesia, Malaysia, the Philippines, Singapore and Viet Nam. Thailand is not listed [S44]. - TBT trends in Asia since 2013. - Republic of Korea. In Jinhae Bay, 5 and 10 years after the total ban, imposex and TBT in rock shells “decreased significantly”. Current low exposure “is still sufficient to cause imposex” [S40]. - Hong Kong. Implementing legislation was enacted only in January 2017. Between 2010 and 2023 butyltins in seawater and total organotins in rock shells fell significantly, and imposex declined. TBT “no longer had significant adverse effects”, but triphenyltin (TPT) “could impact 68% of their populations” [S39]. - Mainland China (Shenzhen, 2013). All female whelks had imposex, and total organotins reached 27,756 μg/kg dry weight, over 97.8% of it triphenyltin. The authors state that “no local restrictions on OT-based antifouling paints have been implemented in China” [S41]. - Review (2026). TBT in sediments and biota is “slowly but gradually decreasing” in continuously observed areas, such as European waters and the Hong Kong coast, with occasional new inputs. “The levels of phenyltins have surpassed butyltins in many Asian sea areas” [S42]. A 2026 Malaysian estuary study likewise found triphenyltin dominant [S43]. - DDT in China. - China withdrew its Stockholm Convention DDT registration (“production and use”) on 28 February 2014 [S45]. The registration’s remarks concern disease-vector control, not antifouling. - Post-2013 studies still attribute DDT enrichment in harbour and coastal sediments to “the use of DDT-containing antifouling paint on vessels, fishing ships, and oil pipes and equipment”, with a slow phase-out [S46]. - I could not confirm from a primary source the date when DDT antifouling use in China formally ended.

Verdict: partly held up. As a snapshot of about 2010, both statements were fair. Since then: - TBT has declined where bans were implemented and enforced; - triphenyltin, a related organotin, has become the dominant residue in parts of Asia; - DDT from past antifouling use persists in sediments.

Implications for weight. - The underlying lesson is well supported: partial or unevenly implemented bans leak, legacy stocks persist, and harm shifts to related compounds that are less regulated. Hong Kong’s local legislation came nine years after the Convention entered into force. - The phenyltin shift adds a variant: one member of a chemical family is controlled while a close relative continues.

Claim 10: Under the Biocidal Products Directive, “a review of all antifouling biocides submitted for approval is well under way. Decisions on the acceptability of these biocides are expected shortly… Products deemed ‘unacceptable’ will be removed from the EU market” (Table 12.3, October 2008 update, p. 272; also p. 271)#

Subsequent developments - Timing. The first EU decisions on antifouling (product type 21) substances came more than five years after the 2008 update [S34, S35]: - zineb (31 January 2014); - DCOIT (29 April 2014); - tralopyril (16 October 2014); - tolylfluanid (March 2015); - copper pyrithione (June 2015); - medetomidine (September 2015); - cybutryne, not approved (27 January 2016); - the three copper compounds (July 2016); - dichlofluanid (May 2017, effective 1 November 2018). - Cybutryne’s path. The Netherlands submitted its assessment in April 2011, and ECHA’s committee gave its opinion in June 2015 [S1]. - Zinc pyrithione. It is one of the three agents the UK permitted in 2001 and is listed for product type 21 in the 2014 review programme [S37]. I found no EU approval or non-approval act for it in Publications Office metadata as of September 2026, so it appears still under review. This rests on metadata only. - The review programme was extended to 2030. Delegated Regulation (EU) 2024/1398 moved the target for completing the existing-substance review from 31 December 2024 to 31 December 2030 [S38]. It cites “substantial delays” due to: - lack of resources in Member States; - applicant delays; - complex technical questions; - evolving guidance; - “the new scientific criteria for the determination of endocrine disrupting properties” introduced in 2017. - Renewals are delayed too. Between 2022 and 2026 the Commission postponed the expiry dates of most approved antifouling substances pending renewal [S21, S23, S24, S26, S65]: - medetomidine, three times; - tralopyril; - DCOIT; - copper pyrithione; - zineb; - dicopper oxide; - copper thiocyanate. - Removal of “unacceptable” substances. - Cybutryne was removed by non-approval [S1]. - Diuron left by 2007 at the latest because it was not in the antifouling review programme, as described under Claim 1 [S36]. - The 2008 Table 12.3 lists only national diuron bans. It does not reflect that diuron had apparently already dropped out of EU antifouling use. - Geographical disparity. The chapter’s concern that rigour “varies between countries” (p. 265) has largely been resolved within the EU by harmonised approval. It persists globally, as the 2026 Brazilian data show [S58].

Verdict: partly held up. The predicted outcome (unacceptable agents removed) occurred for cybutryne. The predicted timing (“shortly”) did not: decisions took 6–9 years after 2008, and the programme as a whole now runs to 2030. The harmonised regime also left a “candidate for substitution” substance on the market for more than a decade (Claim 6).

Implications for weight. This supports the chapter’s implicit contrast between fast national or small-jurisdiction action and slow harmonised review (pp. 271–272). New scientific criteria, here the 2017 endocrine-disruptor criteria, improve protection but also lengthen review cycles. That trade-off lets existing products stay on the market longer.

Summary of verdicts#

Technology-neutral lessons this check supports (for later use as a lens)#

Each is tied to the section’s pages and to the later evidence above.

1. Removing a hazard creates a market for substitutes that inherit a presumption of safety, and the cycle can repeat more than once. After TBT came the boosters (pp. 265, 267, 276). After the boosters came a third generation, one of which was approved while flagged for substitution and later found to meet endocrine-disruptor exclusion criteria [S1, S22–S24, S27].
2. When the useful function is itself the hazard, swapping agents within the same principle moves the harm rather than removing it. Photosystem II inhibitors threaten primary producers “by definition” (pp. 273–274). Regulators later confirmed this for cybutryne and diuron [S1–S6].
3. Screens built around the last hazard can give false reassurance about the next. An oestrogen screen passed agents that later showed effects through hormone synthesis, the thyroid axis, or human endocrine criteria (pp. 265, 270, 275; [S17–S21, S23]).
4. Early “protective” thresholds tend to be too lenient, and claims of success inherit their leniency. The proposed Irgarol benchmark of 24 ng/L became an EU standard of 2.5 ng/L, and diuron’s coastal standard is being tightened about 40-fold (pp. 270, 273; [S4, S5, S14]).
5. Controls at the supply choke point work quickly, but legacy stocks keep releasing long after supply stops. For Irgarol these stocks were sediments, paint residues and paint debris (pp. 268, 273; [S12, S14–S16]).
6. Effectiveness is usually shown only as lower exposure. Ecological benefit is inferred, not observed. No ecological outcome evaluation of a booster-biocide ban was found (p. 276; Claim 4).
7. Harmonised review is slower than local action, and adding new criteria slows it further while existing products stay on the market. Bermuda acted in 2005; the EU on cybutryne in 2016, with the review now extended to 2030 (pp. 271–272; [S1, S38]).
8. Combined stressors can erode safety margins set for single stressors. Heat and herbicide effects add together, and sometimes the combined effect is greater than the sum (p. 270; [S30–S32]).
9. Partial or uneven bans leak, and harm can shift to less-regulated relatives in the same chemical family. TBT gave way to triphenyltin, and DDT persists from legacy antifouling use (pp. 267, 276; [S39–S46]).
10. Incumbents can lead system innovation but tend to keep their core product inside it, and “non-toxic” alternatives bring chemistries of their own that need prior assessment. Robotic cleaning was paired with the maker’s own self-polishing coating; foul-release coatings rely on fluorinated and organosilicon chemistry (p. 275; [S48, S49, S52–S56]).

Sources#

All retrieved 25 September 2026 unless noted. “Abstract only” means I read the abstract via Europe PMC or Crossref, not the full text.

EU biocides legislation and decisions - [S1] Commission Implementing Decision (EU) 2016/107 of 27 January 2016 not approving cybutryne as an existing active substance for use in biocidal products for product-type 21. OJ L 21, 28.1.2016. ELI: http://data.europa.eu/eli/dec_impl/2016/107/oj. Text read at https://www.legislation.gov.uk/eudn/2016/107/contents (XML: https://www.legislation.gov.uk/eudn/2016/107/data.xml). - [S21] Commission Implementing Decision (EU) 2025/1811 of 11 September 2025 postponing the expiry date of the approval of 4,5-Dichloro-2-octyl-2H-isothiazol-3-one (DCOIT) for product-types 8 and 21. ELI: http://data.europa.eu/eli/dec_impl/2025/1811/oj. Read via http://publications.europa.eu/resource/celex/32025D1811 - [S22] Commission Implementing Regulation (EU) 2015/1731 of 28 September 2015 approving medetomidine for product-type 21. ELI: http://data.europa.eu/eli/reg_impl/2015/1731/oj. Read at https://www.legislation.gov.uk/eur/2015/1731/contents - [S23] Commission Implementing Decision (EU) 2025/953 of 23 May 2025 postponing the expiry date of the approval of medetomidine (product-type 21). ELI: http://data.europa.eu/eli/dec_impl/2025/953/oj. Read via http://publications.europa.eu/resource/celex/32025D0953 - [S24] Commission Implementing Decision (EU) 2026/1089 of 20 May 2026 postponing the expiry date of the approval of medetomidine (product-type 21) to 31 December 2026. OJ L, 22.5.2026. ELI: http://data.europa.eu/eli/dec_impl/2026/1089/oj. Read via http://publications.europa.eu/resource/celex/32026D1089 - [S25] Commission Implementing Regulation (EU) No 1091/2014 of 16 October 2014 approving tralopyril as a new active substance for product-type 21. ELI: http://data.europa.eu/eli/reg_impl/2014/1091/oj. Read at https://www.legislation.gov.uk/eur/2014/1091/contents - [S26] Commission Implementing Decision (EU) 2024/2945 of 29 November 2024 postponing the expiry date of the approval of tralopyril (product-type 21) to 30 September 2027. ELI: http://data.europa.eu/eli/dec_impl/2024/2945/oj. Read via http://publications.europa.eu/resource/celex/32024D2945 - [S34] Commission Implementing Regulation (EU) No 437/2014 of 29 April 2014 approving DCOIT for product-type 21 (approval 1 January 2016 to 31 December 2025). https://www.legislation.gov.uk/eur/2014/437/contents - [S35] Other product-type 21 approvals (titles and conditions read at legislation.gov.uk or the Publications Office): - Implementing Regulation (EU) No 92/2014 (zineb), 31 January 2014: https://www.legislation.gov.uk/eur/2014/92/contents - (EU) 2015/419 (tolylfluanid), 12 March 2015: https://www.legislation.gov.uk/eur/2015/419/contents - (EU) 2015/984 (copper pyrithione), 24 June 2015: https://www.legislation.gov.uk/eur/2015/984/contents - (EU) 2016/1088, 2016/1089 and 2016/1090 (copper flakes, dicopper oxide, copper thiocyanate), 5 July 2016: https://www.legislation.gov.uk/eur/2016/1089/contents - (EU) 2017/796 (dichlofluanid), 10 May 2017, approval from 1 November 2018: http://publications.europa.eu/resource/celex/32017R0796 - [S36] Commission Regulation (EC) No 1451/2007 of 4 December 2007 on the second phase of the 10-year work programme (Annex II and Article 4). https://www.legislation.gov.uk/eur/2007/1451/annex/II/adopted and https://www.legislation.gov.uk/eur/2007/1451/contents/adopted - [S37] Commission Delegated Regulation (EU) No 1062/2014 of 4 August 2014 on the work programme for the systematic examination of existing active substances (Annex II). https://www.legislation.gov.uk/eur/2014/1062/annex/II/adopted - [S38] Commission Delegated Regulation (EU) 2024/1398 of 14 March 2024 amending Regulation (EU) No 528/2012 as regards a further extension of the duration of the work programme (to 31 December 2030). ELI: http://data.europa.eu/eli/reg_del/2024/1398/oj. Read via http://publications.europa.eu/resource/celex/32024R1398 - [S65] Further postponement decisions, 11–12 September 2025 (titles only, from EU Publications Office metadata): - (EU) 2025/1778 (copper pyrithione, to 30 June 2028; text read): http://publications.europa.eu/resource/celex/32025D1778 - (EU) 2025/1809 (zineb): http://data.europa.eu/eli/dec_impl/2025/1809/oj - (EU) 2025/1812 (dicopper oxide): http://data.europa.eu/eli/dec_impl/2025/1812/oj - (EU) 2025/1807 (copper thiocyanate): http://data.europa.eu/eli/dec_impl/2025/1807/oj - (EU) 2022/1495 (medetomidine, 8 September 2022): http://data.europa.eu/eli/dec_impl/2022/1495/oj

EU water legislation and EEA - [S4] Directive 2013/39/EU of 12 August 2013 amending Directives 2000/60/EC and 2008/105/EC as regards priority substances. OJ L 226, 24.8.2013. ELI: http://data.europa.eu/eli/dir/2013/39/oj. Read via http://publications.europa.eu/resource/celex/32013L0039 - [S5] Directive (EU) 2026/805 of 30 March 2026 amending Directives 2000/60/EC, 2006/118/EC and 2008/105/EC. OJ L, 20.4.2026. ELI: http://data.europa.eu/eli/dir/2026/805/oj. Read via http://publications.europa.eu/resource/celex/32026L0805 - [S59] European Environment Agency, Europe’s state of water 2024. https://www.eea.europa.eu/en/analysis/publications/europes-state-of-water-2024

IMO and Stockholm Convention - [S2] IMO, International Convention on the Control of Harmful Anti-fouling Systems on Ships (AFS) (adopted 5 October 2001; in force 17 September 2008; cybutryne amendments in force 1 January 2023). https://www.imo.org/en/about/Conventions/Pages/International-Convention-on-the-Control-of-Harmful-Anti-fouling-Systems-on-Ships-(AFS).aspx - [S3] IMO, Anti-fouling (MEPC 71 rationale; MEPC 76 adoption, June 2021; removal-or-sealing rule; 2022 guidelines; 2024 guidance). https://www.imo.org/en/OurWork/Environment/Pages/Anti-fouling.aspx. See also the MEPC 76 press briefing: https://www.imo.org/en/MediaCentre/PressBriefings/pages/MEPC76.aspx - [S44] IMO, Status of Treaties spreadsheet, “As at 25 August 2026” (AFS column). https://wwwcdn.imo.org/localresources/en/About/Conventions/StatusOfConventions/x-Status.xlsx - [S45] Stockholm Convention, DDT Register (China: production and use, notified 2 February 2005, withdrawn 28 February 2014). https://chm.pops.int/Implementation/Exemptions/AcceptablePurposesDDT/tabid/456/Default.aspx

Peer-reviewed literature: hazard, corals, multiple stressors - [S6] Ouédraogo DY et al. (2023). What are the toxicity thresholds of chemical pollutants for tropical reef-building corals? A systematic review. Environmental Evidence. https://doi.org/10.1186/s13750-023-00298-y (abstract) - [S7] Kamei M, Takayama K, Ishibashi H, Takeuchi I (2020). Effects of ecologically relevant concentrations of Irgarol 1051 in tropical to subtropical coastal seawater on hermatypic coral Acropora tenuis and its symbiotic dinoflagellates. Marine Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2019.110734 (abstract) - [S30] Negri AP, Flores F, Röthig T, Uthicke S (2011). Herbicides increase the vulnerability of corals to rising sea surface temperature. Limnology and Oceanography 56(2): 471. https://doi.org/10.4319/lo.2011.56.2.0471 (abstract via Crossref) - [S31] Negri AP, Smith RA, King O, Frangos J, Warne MSJ, Uthicke S (2020). Adjusting tropical marine water quality guideline values for elevated ocean temperatures. Environmental Science & Technology. https://doi.org/10.1021/acs.est.9b05961 (abstract) - [S32] Gushi M, Ishibashi H, Takayama K, Yamashiro H, Takeuchi I (2025). Interactive effects of high seawater temperature and the PS II herbicide Irgarol 1051 on photosynthetic efficiency of one species of the Acropora tenuis [sensu lato] complex. Marine Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2025.118098 (abstract) - [S33] Marzonie M et al. (2021). Toxicity thresholds of nine herbicides to coral symbionts (Symbiodiniaceae). Scientific Reports. https://doi.org/10.1038/s41598-021-00921-3 (abstract) - [S64] Mochida K, Hano T, Onduka T, Ito K, Yoshida G (2019). Physiological responses of eelgrass (Zostera marina) to ambient stresses such as herbicide, insufficient light, and high water temperature. Aquatic Toxicology. https://doi.org/10.1016/j.aquatox.2018.12.018 (title only) - [S29] Martins SE, Fillmann G, Lillicrap A, Thomas KV (2018). Review: ecotoxicity of organic and organo-metallic antifouling co-biocides and implications for environmental hazard and risk assessments in aquatic ecosystems. Biofouling. https://doi.org/10.1080/08927014.2017.1404036 (abstract)

Peer-reviewed literature: field concentrations - [S8] Sheikh MA et al. (2016). Occurrence and distribution of antifouling biocide Irgarol-1051 in coral reef ecosystems, Zanzibar. Marine Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2016.05.035 (abstract) - [S9] Batista-Andrade JA et al. (2016). Antifouling booster biocides in coastal waters of Panama. Marine Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2016.07.045 (abstract) - [S10] Munaron D et al. (2023). Evaluating pesticide mixture risks in French Mediterranean coastal lagoons waters. Science of the Total Environment. https://doi.org/10.1016/j.scitotenv.2022.161303 (abstract) - [S11] Daehne D, Fürle C, Thomsen A, Watermann B, Feibicke M (2017). Antifouling biocides in German marinas: exposure assessment and calculation of national consumption and emission. Integrated Environmental Assessment and Management 13: 892–905. https://doi.org/10.1002/ieam.1896 (abstract) - [S12] Koning JT, Bollmann UE, Bester K (2020). The occurrence of modern organic antifouling biocides in Danish marinas. Marine Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2020.111402 (abstract) - [S13] Marras B et al. (2026). Labile concentration of trace metals and organic substances in western Mediterranean ports. Marine Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2025.118769 (abstract) - [S14] Zhou JL (2008). Occurrence and persistence of antifouling biocide Irgarol 1051 and its main metabolite in the coastal waters of Southern England. Science of the Total Environment. https://doi.org/10.1016/j.scitotenv.2008.07.049 (abstract) - [S15] Cresswell T, Richards JP, Glegg GA, Readman JW (2006). The impact of legislation on the usage and environmental concentrations of Irgarol 1051 in UK coastal waters. Marine Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2006.01.014 (abstract; checked for the chapter’s “10–55 %” wording) - [S16] Hasan CK, Turner A, Readman J, Frickers T (2014). Environmental risks associated with booster biocides leaching from spent anti-fouling paint particles in coastal environments. Water Environment Research. https://doi.org/10.2175/106143014x14062131178835 (abstract) - [S43] Mukhtar A, Zulkifli SZ, Harino H, Ismail A (2026). Tissue-specific distribution of organotin and booster biocides in marine organisms from seagrass area of Pulai River Estuary, Malaysia. Environmental Monitoring and Assessment. https://doi.org/10.1007/s10661-026-15134-2 (abstract) - [S57] Molino C, Angeletti D, Oldham VE, Goodbody-Gringley G, Buck KN (2019). Effect of marine antifouling paint particles waste on survival of natural Bermuda copepod communities. Marine Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2019.110492 (abstract) - [S58] Diniz LGR et al. (2026). Antifouling booster biocides diuron and irgarol at Brazilian ports. Marine Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2025.118755 (abstract)

Peer-reviewed literature: endocrine and other effects of substitutes - [S17] Chen L, Ye R, Xu Y, Gao Z, Au DW, Qian PY (2014). Comparative safety of the antifouling compound butenolide and DCOIT to the marine medaka (Oryzias melastigma). Aquatic Toxicology. https://doi.org/10.1016/j.aquatox.2014.01.023 (abstract) - [S18] Chen L et al. (2016). Chronic exposure of marine medaka to DCOIT reveals its mechanism of action in endocrine disruption via the hypothalamus–pituitary–gonadal–liver (HPGL) axis. Environmental Science & Technology. https://doi.org/10.1021/acs.est.6b01137 (abstract) - [S19] Chen L, Lam JCW (2017). SeaNine 211 as antifouling biocide: a coastal pollutant of emerging concern. Journal of Environmental Sciences (China). https://doi.org/10.1016/j.jes.2017.03.040 (abstract) - [S20] Liu M, Hu C, Li J, Zhou B, Lam PKS, Chen L (2024). Thyroid endocrine disruption and mechanism of the marine antifouling pollutant DCOIT. Environmental Science & Technology. https://doi.org/10.1021/acs.est.4c07614 (abstract) - [S27] Lagerström M et al. (2026). Sustainability ranking of antifouling coatings for leisure boats: balancing efficacy and environmental impact. Journal of Hazardous Materials. https://doi.org/10.1016/j.jhazmat.2026.141600 (abstract) - [S28] Liu B et al. (2026). Behavioral toxicity of tralopyril in Oryzias melastigma: integrated consequences of multi-organ damage and thyroid hormone dysregulation. Journal of Hazardous Materials. https://doi.org/10.1016/j.jhazmat.2026.141304 (abstract) - [S60] Horie Y, Chihaya Y, Jiang JJ (2026). Thyroid hormone disruption and developmental toxicity of diuron and Irgarol 1051 in zebrafish (Danio rerio) larvae. Journal of Applied Toxicology. https://doi.org/10.1002/jat.70237 (abstract) - [S60b] Kamarudin NA et al. (2020). Herbicide diuron as endocrine disrupting chemicals (EDCs) through histopathological analysis in gonads of Javanese medaka. Animals. https://doi.org/10.3390/ani10030525 (abstract)

Peer-reviewed literature: organotins and DDT - [S39] Jiang Y et al. (2025). Positive impact of the legislation on organotins contamination in the marine environment of Hong Kong. Environment International. https://doi.org/10.1016/j.envint.2025.109486 (abstract) - [S40] Kim NS, Hong SH, Shin KH, Shim WJ (2017). Imposex in Reishia clavigera as an indicator to assess recovery of TBT pollution after a total ban in South Korea. Archives of Environmental Contamination and Toxicology. https://doi.org/10.1007/s00244-017-0369-x (abstract) - [S41] Ho KK, Leung KM (2014). Spatio-temporal comparisons of imposex status and tissue organotin concentration in the whelk Reishia clavigera collected along the coasts of Dapeng Bay and Daya Bay, Shenzhen, China. Marine Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2014.06.017 (abstract) - [S42] Pang J, Chen H, Huang S, Zhang Y, Lin K (2026). Both legacy and emerging: organotin pollutants in marine environments. Marine Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2026.119599 (abstract) - [S46] Shi X et al. (2026). Organochlorine pesticides (OCPs) in the sediment of the Bohai Sea in China: slow phasing out but risk remaining. Marine Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2025.118833 (abstract)

Alternatives: foul-release coatings, cleaning, industry - [S48] Lagerström M, Wrange AL, Oliveira DR, Granhag L, Larsson AI, Ytreberg E (2022). Are silicone foul-release coatings a viable and environmentally sustainable alternative to biocidal antifouling coatings in the Baltic Sea region? Marine Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2022.114102 (abstract) - [S49] Adouane E et al. (2026). Efficacy, microbial disruption, and algal toxicity of commercial antifouling coatings: a multi-level assessment. Marine Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2026.119303 (abstract) - [S50] Papadatou M, Robson SC, Dobretsov S, Watts JEM, Longyear J, Salta M (2021). Marine biofilms on different fouling control coating types reveal differences in microbial community composition and abundance. MicrobiologyOpen. https://doi.org/10.1002/mbo3.1231 (open-access full text; the “>90% of coatings sales” statement cites Lejars et al. 2012 and Winfield et al. 2018) - [S51] Fore M (2020). Seeking nontoxic coatings to keep ship hulls clean. ACS Central Science 6: 1644–1646 (news feature; secondary). https://doi.org/10.1021/acscentsci.0c01350 - [S52] Jotun, Hull Skating Solutions: overview (company web page; partners Kongsberg Maritime, Wallenius Wilhelmsen, DNV; SeaQuantum Skate silyl-acrylate coating). https://www.jotun.com/ww-en/products-and-services/solutions-and-brands/hull-skating-solutions/overview - [S53] Jotun, “Carnival Cruise Line pioneers hull cleaning for cruise operations with Jotun”, 4 August 2026 (company news). https://www.jotun.com/ww-en/news-and-insights/jotun-insider/carnival-cruise-line-pioneers-hull-cleaning-for-cruise-operations-with-jotun - [S54] Lastoria GC, Zhao Y, Jobst KJ (2026). A prioritized database of substances of environmental concern used in marine coatings. ACS ES&T Water. https://doi.org/10.1021/acsestwater.6c00103 (abstract) - [S55] Shin D et al. (2023). Chemical hazard of robotic hull in-water cleaning discharge on coastal embryonic fish. Ecotoxicology and Environmental Safety. https://doi.org/10.1016/j.ecoenv.2023.114653 (abstract) - [S56] Lee B et al. (2025). Effects of hull cleaning wastewater on coastal plankton community: a mesocosm experiment. Journal of Hazardous Materials. https://doi.org/10.1016/j.jhazmat.2025.139458 (abstract) - [S61] Tribou M et al. (2026). The influence of location and coating on the development of an in-water grooming program to maintain ship hull coatings. Biofouling. https://doi.org/10.1080/08927014.2026.2621192 (abstract)

Original authors’ later work (checked for revisions of the chapter’s claims) - [S62] Aminot Y, Belles A, Alary C, Readman JW (2017). Near-surface distribution of pollutants in coastal waters as assessed by novel polyethylene passive samplers. Marine Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2017.03.022 (abstract) - [S63] Price ARG et al. (2014). Shifting environmental baselines in the Red Sea. Marine Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2013.10.055 (title only)