We measured the concentrations of antifouling biocides in sediment, mangrove leaves and seagrasses from Merambong and Tinggi Island, Johor, Malaysia to evaluate their contamination levels. Although the concentrations of tributyltin (TBT) in mangrove leaves in Merambong in 2013 were significantly lower than those in 2012, the Sea-Nine 211 concentration in 2013 was significantly higher than that in 2012, suggesting that the use of antifouling biocides changed from TBT to Sea-Nine 211. The concentration of each BT (butyltin) and PT (phenyltin) in the mangrove area was significantly higher than the corresponding concentration in the seagrass area in Merambong, but the concentrations of Sea-Nine 211, diuron, chlorothalonil, Irgarol 1051 and M1 in seagrasses were significantly higher than those in mangrove leaves. There were differences in the accumulation profiles of OTs (organotins) and alternative biocides between the seagrass shoots and roots. The concentration of OTs in the seagrass roots was almost the same or higher than those in the shoots, whereas those of alternative biocides shows the opposite pattern to the OTs. Significant high relationships were observed between stable carbon isotope (δ13C) and OTs, Sea-Nine 211 and Irgarols in mangrove leaves. The concentrations of these compounds increased along with the δ13C values of the mangroves. These results suggest that mangroves take up the bicarbonate ions and nutrients in sediment and/or seawater through their roots, along with OTs, Sea-Nine 211 and Irgarols which were accumulated in sediment.

The concentrations of organotin (OT) compounds, butyltin (BT) and phenyltin (PT), in aquatic organisms from Merambong and Tinggi Island, Malaysia, which differ in industrial and economic activities, were measured. Tributyltin (TBT) compounds among BTs ranged from 2.9–28 and <0.1–21 ng g−1 ww in aquatic organisms from Merambong and Tinggi Island, respectively. Triphenyltin (TPT) compounds among PTs ranged from <0.1–25 ng g−1 ww and <0.1–61 ng g−1 ww in aquatic organisms from Merambong and Tinggi Island, respectively. A survey of OT concentrations among the species of OT compounds revealed that the concentrations of BTs and PTs in crabs and clams were high while those in fish were low. Correlation analysis with stable nitrogen isotopes suggest that OT compounds did not accumulate in aquatic organisms through the food web. The measurement of OT compounds in tissues and organs of fish revealed that BT concentrations in liver were higher than those in muscle and that BTs were detected in eggs of fish.

Tributyltin (TBT) and triphenyltin (TPT) concentrations in water samples from Tanabe Bay were found to range from 4–28 ng l−1 and 3–7 ng l−1, respectively. In fishing ports, the concentrations of TBT in surface water were similar to those in bottom water. However, in aquafarming areas with poor flushing, the concentrations of TBT in bottom water were higher than those in surface water. This suggested that the TBT in water samples is re-eluted from sediment. No difference in the concentration of TPT was observed between the surface and bottom waters. The concentrations of TBT and TPT in sediment samples ranged from 3–23 μg kg−1 dry weight and 2–37 μg kg−1 dry weight. TBT and TPT concentrations ranged from 3.1–100 μg kg−1 and 3.1–7.2 μg kg−1 in oysters and gastropods, and from 1.1–4.9 μg kg−1 and ＜0.2–3.9 μg kg−1 in fish, respectively. Organotin concentrations in biota were lower than the tolerable average residue levels (TARLs). Alternative biocides – i.e. diuron, chlorothalonil, dichlofluanid, irgarol 1051 and Sea-Nine 211 – were also detected in surface water, and chlorothalonil and irgarol 1051 were detected in sediment. The concentrations of these compounds in surface water and sediment were lower than those reported previously. Dichlofluanid, chlorotharonil and irgarol 1051 were also found at low levels in oysters and gastropods, and at ranges of 325–339 μg kg−1, 268–291 μg kg−1 and 43–49 μg kg−1, respectively, in fish; the concentrations in fish were close to the TARL levels.

To elucidate the details of both the current status of contamination and the accumulation of organotin compounds (OTs) in mangroves in coastal ecosystems, we determined the concentrations of butyltin compounds (BTs) and phenyltin compounds (PTs) in sediment and mangrove leaves collected from mangrove forests in Merambong and Tinggi Island, Malaysia. Butyltins were detected in all sediment samples collected from both regions, whereas PTs were not detected. The levels of tributyltin (TBT) compounds in the sediment samples were lower than those from previous studies conducted in Malaysia and at other sites in South-east Asia. In both Merambong and Tinggi Island, the average proportions of dibutyltin (DBT) and monobutyltin (MBT), which are degradation products of TBT, were ~70%. This result suggests that the input of TBT has decreased in Malaysia. The proportions of DBT and MBT in the sediment from Merambong were higher than those from Tinggi Island. The concentrations of TBT in mangrove leaves from Tinggi Island were significantly higher than those from Merambong. MBT was the most dominant type among the BTs in mangrove leaves from both Merambong and Tinggi Island. The ratios of the BTs burden in mangrove leaves to the BTs concentration in sediment from Merambong and Tinggi Island averaged 3.1 and 6.2, respectively. Among the values of BTs, the MBT values were found to be the highest in both regions.

The susceptibility of marine bacterial communities to copper pyrithione (CuPT2), zinc pyrithione (ZnPT2) and their degradation product is described and toxicities of these relatively new antifouling biocides compared with those of their harmful organotin (OT) predecessors, tributyltin (TBT) and triphenyltin (TPT). These biocides were added to agar at concentrations of 0, 0.01, 0.1, 1 and 10 mg l−1 and coastal seawater including indigenous bacteria added to each batch of agar solution. The number of bacterial colony forming units (CFU) was measured after 7 days culture. Relative CFU (as a percentage of control) was more than 80% at a concentration of 0.01 mg l−1 of each compound, except for TBT. Relative CFU decreased as a function of dose of each biocide, although concentration-dependent changes in rate of CFU were relatively low during exposure to degradation products of CuPT2 and ZnPT2, pyridine N-oxide (PO) and pyridine-2-sulphonic acid (PSA). Based on comparisons of EC50, TBT was the most bacterio-toxic of the tested compounds (0.2 mg l−1), marginally more so than CuPT2 (0.3 mg l−1). Interestingly, EC50 values of degradation products of CuPT2 and ZnPT2, 2-mercaptopyridine N-oxide (HPT) and 2,2′-dithio-bispyridine N-oxide (PT2) were 0.8 and 0.5 mg l−1, respectively, lower than that of the parent chemical, ZnPT2 (1.4 mg l−1). The EC50 of PT2 was also lower than that of TPT (0.7 mg l−1), implying higher toxicity. Given the overlapping toxicity ranges, these results suggest that marine bacterial communities experience comparably high susceptibility to metal PTs and OTs during their life history.

To examine the risk of transgenerational transfer of organotin compounds (OTs) in fish, tributyltin (TBT) and triphenyltin (TPT) compounds and their breakdown products were determined in both parental females and offspring of viviparous surfperch Ditrema temmincki collected from Japanese coastal waters. TBT concentrations (Mean ± SD) in the offspring (34 ± 5.7 ng Sn g−1 wet wt) were significantly higher (10–17 times) than in the parental females (2.8 ± 1.0 ng Sn g−1 wet wt). In the offspring, TBT was the predominant butyltin compound (82 ± 1.6% ∑BTs = TBT + DBT + MBT), and represented a greater proportion than in the parental females (51 ± 9.3% as TBT). TPT concentrations were significantly lower than TBT, and the ratio of TPT in parental females, relative to offspring, was different from TBT. TPT concentrations in the offspring (0.8 ± 0.3 ng Sn g−1 wet wt) were almost identical to those in the parental females (1.0 ± 0.5 ng Sn g−1 wet wt). TPT was the predominant phenyltin (∑PTs = TPT + DPT + MPT) in both offspring (73 ± 12% as TPT) and parental females (72 ± 18% as TPT). Results suggest that the transfer rate of TBT from parent to offspring could be much faster than its degradation rate in the offspring, accounting for higher accumulation of TBT in the latter. In contrast, the transfer rate of TPT is slower than its biodegradation, leading to a lower concentration of TPT in the offspring. It is therefore likely that the offspring might be at a higher risk from TBT than the parental females during their early growth stage in ovary in the viviparous surfperch whereas exposure to TPT is comparable in both generations.

The concentrations of organophosphoric acid triesters (OPEs) in water samples from Maizuru Bay were in the range of 3.0–62 ng/l. In general, the concentrations of OPEs were found in the order of TBXP > TDCPP > TCEP > TBP > TCP > TPP > TEP. The organophosphorous pesticides (OPPs) diazinon, fenitrothion, iprobenfos and chlorpyrifos were detected in water samples. The concentrations of OPEs in sediment from Maizuru Bay were in the range of <0.5–56 µg kg−1 dry weight (dw). Among OPPs, diazinon in sediment samples were in the range of 1.8–71 µg kg−1 dw. However, the detection frequencies of fenitrothion and chlorpyrifos in sediment were low. The concentrations of OPEs in mussels from Maizuru Bay were in the range of <1–34 µg kg−1 wet weight (ww). The concentrations of OPEs were found in the order of TBP > TDCPP > TCP > TBXP = TPP = TCEP. Pesticides were detected in mussels, but these concentrations were lower than the acceptable daily intake (ADI) values. The partition coefficients between water and sediment (Kws) of diazinon and fenitrothion were 200–1300 and 200–300, respectively and the partition coefficients between water and biological samples (Kwb) of diazinon and fenitrothion were 700–3300 and 450–700, respectively, suggesting that these pesticides accumulate in biological samples at higher rates than in sediment.

An analytical method for the simultaneous determination of five booster biocides (Sea-Nine 211, Dichlofluanid, Duiron, Irgarol 1051 and Pyrithiones) and degradation product of Irgarol 1051 (M1) in sediment from Vietnam was developed by LC/MS-MS. The recovery rates and relative standard deviation of the booster biocides in the sediment were in the range of 71–108% and 1.5–12%, respectively, and the detection limits were in the range of 0.04–2 μg kg−1 dry. An analytical method for the simultaneous determination of three booster biocides (Sea-Nine 211, Duiron and Irgarol 1051) and M1 in clams was also developed by LC/MS-MS. The recovery rates and relative standard deviations of the booster biocides in the biological samples were in the range of 60–99% and 3.4–6.8%, respectively, and the detection limits were in the range of 0.24–1.1 μg kg−1.

The booster biocides in sediment from the coastal area of northern and central Vietnam were measured using this analytical method. Sea-Nine 211, Dichlofluanid, Duiron, Irgarol 1051, M1 and Pyrithiones were detected in the range of 0.09–1.3 μg kg−1 dry, <0.10–13 μg kg−1 dry, 0.11–3.0 μg kg−1 dry, 0.05–4.0 μg kg−1 dry, <0.1–0.43 μg kg−1 dry and <2–420 μg kg−1 dry, respectively. The detection frequencies of Dichlofluanid, M1 and Pyrithiones were low. The species and levels of detected booster biocides varied between sampling stations.

Irgarol 1051 and its degradation product M1 were not detected in clams.

The concentrations of booster compounds were surveyed in the port of Osaka, Japan. The concentrations of Sea-Nine 211, Diuron and Irgarol 1051 in water samples from the port of Osaka were in the ranges <0·30–0·55 ng l−1, 13–350 ng l−1, 1·3–77 ng l−1, respectively. Pyrithiones were not detected in water samples. The levels of Diuron and Irgarol 1051 in the port of Osaka were high in the mooring area for small and medium-hull vessels with poor flushing.

Susceptibility of bacterial populations in estuarine water to antifouling biocides was studied. Sea-Nine 211, Diuron, Irgarol 1051 and Copper pyrithione dissolved in dimethyl sulfoxide (DMSO) were added to estuarine water and number of colony forming units (CFU) of bacteria in estuarine water was counted using R2A agar plate. The CFU was not decreased at the concentration less than 1·0 mg/l of Diuron, Irgarol 1051 and Copper pyrithione. However, CFU was decreased at 0·1 mg/l of Sea-Nine 211. Degradation of Sea-Nine 211, Diuron, Irgarol 1051 and Copper pyrithione by bacteria in estuarine water was studied using a die-away method. At an initial concentrations of 0·1 mg/l, observed half-lives of Sea-Nine 211 and Copper pyrithione were 10 and 20 days, respectively. In contrast, Diuron and Irgarol 1051 were degraded scarcely during 60 days of culture.

Photodegradation of these booster biocides by sunlight and UV light were studied. Under UV, all biocides were below detection limit after one day of irradiation. Under sunlight, Copper pyrithiones were also below detection limits after one day. Drastic decrease of Sea-Nine 211 concentration was observed after one day. Diuron and Irgarol 1051 scarcely decreased during 17 days of sunlight irradiation.