Bioaccumulation surveillance in Milford Haven Waterway

Biomonitoring of contaminants (metals, organotins, PAHs, PCBs) was carried out along the Milford Haven Waterway (MHW) and at a reference site in the Tywi Estuary during 2007-2008. The species used as bioindicators encompass a variety of uptake routes - Fucus vesiculosus (dissolved contaminants); Littorina littorea (grazer); Mytilus edulis and Cerastoderma edule (suspension feeders); and Nereis diversicolor (omnivore which often reflects contaminants in sediment). Differences in feeding strategy and habitat preference have subtle implications for bioaccumulation trends though, with few exceptions, contaminant body burdens in Milford Haven (MH) were higher than those at the Tywi reference site, reflecting inputs. Elevated concentrations of metals were occasionally observed at individual MH sites, whilst As and Se (molluscs and seaweed) were, for much of MHW, consistently at the higher end of the UK range. However, for the majority of metals, distributions in MH biota were not exceptional by UK standards. Several metal-species combinations indicated increases in bioavailability at upstream sites, which may reflect the influence of geogenic or other land-based sources – perhaps enhanced by lower salinity (greater proportions of more bioavailable forms). TBT levels in MH mussels were below OSPAR toxicity thresholds and in the Tywi were close to zero. Phenyltins were not accumulated appreciably in Mytilus, whereas some Nereis populations may have been subjected to localized (historical) sources. PAHs in Nereis tended to be evenly distributed across most sites, but with somewhat higher values at Dale for acenaphthene, fluoranthene, pyrene, benzo(a)anthracene and chrysene; naphthalenes tended to be enriched further upstream in the mid-upper Haven (a pattern seen in mussels for most PAHs). Whilst concentrations in MH mussels were mostly above reference site and OSPAR backgrounds, it is unlikely that ecotoxicological guidelines would be exceeded. PCBs in mussels were between upper and lower OSPAR guidelines and were unusual in their distribution in that highest levels occurred at the mouth of MH. Condition indices (CI) of bivalves (mussels and cockles) were highest at the Tywi reference site and at the seaward end of MH, decreasing upstream along the Waterway. There were a number of significant (negative) relationships between CI and body burdens and multivariate analysis indicated that a combination of contaminants could influence the pattern in condition (and sub-lethal responses such as MT and TOSC) across sites. Cause and effect needs to be tested more rigorously in future assessments

Differences in bioaccumulation and transfer ability between tributyltin and triphenyltin from parental female to offspring in viviparous surfperch Ditrema temmincki

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

Drug resistance-conferring mutations in Mycobacterium tuberculosis from Madang, Papua New Guinea

ABSTRACT: BACKGROUND: Monitoring drug resistance in Mycobacterium tuberculosis is essential to curb the spread of tuberculosis (TB). Unfortunately, drug susceptibility testing is currently not available in Papua New Guinea (PNG) and that impairs TB control in this country. We report for the first time M. tuberculosis mutations associated with resistance to first and second-line anti-TB drugs in Madang, PNG. A molecular cluster analysis was performed to identify M. tuberculosis transmission in that region. RESULTS: Phenotypic drug susceptibility tests showed 15.7% resistance to at least one drug and 5.2% multidrug resistant (MDR) TB. Rifampicin resistant strains had the rpoB mutations D516F, D516Y or S531L; isoniazid resistant strains had the mutations katG S315T or inhA promoter C15T; streptomycin resistant strains had the mutations rpsL K43R, K88Q, K88R), rrs A514C or gidB V77G. The molecular cluster analysis indicated evidence for transmission of resistant strain. CONCLUSIONS: We observed a substantial rate of MDR-TB in the Madang area of PNG associated with mutations in specific genes. A close monitoring of drug resistance is therefore urgently required, particularly in the presence of drug-resistant M. tuberculosis transmission. In the absence of phenotypic drug susceptibility testing in PNG, molecular assays for drug resistance monitoring would be of advantag

Ecotoxicity of the degradation products of triphenylborane pyridine (TPBP) antifouling agent

Triphenylborane pyridine (TPBP) is an alternative to organotin antifouling compounds. This work aimed to identify the unknown Peak #1, and to evaluate the ecotoxicity of TPBP and its degradation products. Peak #1 was produced from TPBP dissolved in acetonitrile under UV-A photolysis using a high-pressure mercury lamp. The Peak #1 fraction was purified using two-step column chromatography from a TPBP-acetonitrile solution. The major compound of the fraction was identified as being biphenyl from the H NMR and C NMR spectra. The ecotoxicity of four degradation products (diphenylborane hydroxide, phenylborane dihydroxide, phenol, and biphenyl) and TPBP towards two marine planktons were assessed. The 48 h LC values of the crustacean, Artemia salina, were 0.13 mg L for TPBP, 14 mg L for biphenyl, 17 mg L for phenol, and >50 mg L for the other degradation products. The 72 h EC values of the diatom, Skeletonema costatum, were 0.0022 mg L for TPBP, 1.2 mg L for biphenyl, and >2 mg L for the other degradation products. Thus, the ecotoxicity of biphenyl and the other degradation products were not high compared to the parent compound, TPBP

Real time fixation point monitoring system for photocoagulation of juxtafoveal neovascularisation

BACKGROUND/AIMS—A new real time monitoring system has been developed to locate the fixation point during juxtafoveal laser photocoagulation.
METHOD—The red diode laser beam is combined coaxially with the illumination beam to image a cross in the focal plane of the slit lamp, which allows projection of a red cross onto the patient's fundus. 27 patients with juxtafoveal choroidal neovascularisation were treated by photocoagulation using this system.
RESULTS—13 (48%) patients whose visual acuity ranged from 20/200 to 20/40 answered that it was easier to keep the focus on the cross target image than on the aiming beam. The patient maintained stable fixation throughout the treatment. The laser treatment was completed without foveal damage near the fixation point in all patients.
CONCLUSION—The real time fixation monitoring system should allow surgeons to treat juxtafoveal lesions with laser photocoagulation more safely and accurately. 


Organotin compounds in Mersey and Thames Estuaries a decade after UK TBT legislation

Organotin (OT) compounds were determined in surface sediments and mussels Mytilus edulis from two major estuaries of the UK, the Mersey and the Thames, approximately one decade after legislation banning the use of tributyltin (TBT) compounds on small boats. Tributyltin concentrations in Mersey sediments ranged from 0·007–0·173 μg (as Sn) g−1 dry wt, increasing from the most upstream site, Fiddlers Ferry, towards the middle section of the estuary, and were highest at Stanlow, perhaps indicative of sources from the Manchester Ship Canal (MSC). A further peak in TBT concentrations occurred at New Brighton, opposite Liverpool Docks. Tributyltin was the predominant butyltin (BT) species in sediments (approximately 50%). Despite the fact that BTs represented only 4% of the total (HNO3-extractable) tin in sediments there was a linear relationship between these two tin compartments. Furthermore, BTs in mussels were correlative with total extractable tin in sediment, though in contrast to sediments, 85% of the total tin in mussels was made up of BTs, the most predominant of which was TBT. Concentrations of TBT in mussels increased from 0·058 μg Sn g−1 dry wt at the mouth of the estuary to 0·214 μg Sn g−1 dry wt at their upstream limit, close to the entrance to the MSC (Eastham). Triphenyltin (TPT) compounds were detected in only one sediment sample (New Brighton, 0·359 μg Sn g−1 dry wt) and one mussel population (Egremont, 0·022 μg Sn g−1 dry wt). Tributyltin concentrations in sediments from the Thames Estuary were marginally lower (0·002–0·078 μg Sn g−1 dry wt) than those found in the Mersey: highest concentrations were present in the upper estuary and decreased seaward. Again BTs contributed only a small percentage (&lt;1% mean) towards the total tin loading in Thames sediments, but represented most of the tin burden (80%) in mussels. In contrast to sediments, TBT levels in mussels from the Thames Estuary were slightly higher than the Mersey (concentrations ranged from 0·100 μg Sn g−1 dry wt at the mouth to 0·302 μg Sn g−1 dry wt upstream) suggesting that TBT bioavailability is disproportionately higher in the Thames. Phenyltins were not detected in Thames samples.</jats:p