Chemical Contamination of Green Turtle (Chelonia mydas) Eggs in Peninsular Malaysia: Implications for Conservation and Public Health

BACKGROUND: Persistent organic pollutants (POPs)-such as organochlorine pesticides (OCPS), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs)-and heavy metals have been reported in sea turtles at various stages of their life cycle. These chemicals can disrupt development and function of wildlife. Furthermore, in areas such as Peninsular Malaysia, where the human consumption of sea turtle eggs is prevalent, egg contamination may also have public health implications. OBJECTIVE: In the present study we investigated conservation and human health risks associated with the chemical contamination of green turtle (Chelonia mydas) eggs in Peninsular Malaysia. METHODS: Fifty-five C mydas eggs were collected from markets in Peninsular Malaysia and analyzed for POPs and heavy metals. We conducted screening risk assessments (SRAs) and calculated the percent of acceptable daily intake (ADI) for POPs and metals to assess conservation and human health risks associated with egg contamination. RESULTS: C mydas eggs were available in 9 of the 33 markets visited. These eggs came from seven nesting areas from as far away as Borneo Malaysia. SRAs indicated a significant risk to embryonic development associated with the observed arsenic concentrations. Furthermore, the concentrations of coplanar PCBs represented 3-300 times the ADI values set by the World Health Organization. CONCLUSIONS: The concentrations of POPs and heavy metals reported in C mydas eggs from markets in Peninsular Malaysia pose considerable risks to sea turtle conservation and human health

Stereochemistry of Trifluoroacetolysis and Brominolysis of the Cyclohexyl-Tin Bond

(cis- and trans-4-methyl- and 4-tert-(butylcyclohexyl)triisopropylstannanes have been synthesized and fully characterized. Trifluoroacetolysis of these compounds proceeds stereospecifically with retention of configuration at carbon. Electrophilic bromination is characterized by a fine energetic balance between inversion and retention pathways, with the former favored for the equatorial carbon-tin bonds and the latter for axial carbon-tin bonds in these triisopropylstannanes. Bromination under free-radical conditions yields a statistical mixture of the cis- and trans-4-alkylcyclohexyl bromides, a result appropriate for bromine atom transfer to a 4-alkylcyclohexyl free radical

(Pentaalkylditin)lithiums: Significant Species in Some (Trialkyltin)lithium Preparations

(Pentaalkyliditin)lithiums are demonstrated to be present in preparations of (trialkyltin)lithium reagents (from the trialkyltin halide and lithium in tetrahydrofuran) by direct observation (Sn NMR) and alkylation to RSnR′ (R = methyl, n-propyl, isopropyl; R′ = cyclohexyl, methyl). Cyclohexylation of (i-CH)SnLi proceeds by a free radical route. The RSnLi species are considered to arise by oxidative addition of RSnLi to RSn, formed by [formula omitted], dissociation of which is promoted by RSn scavenging of RLi

Conformational Preference of the Trimethylsilyl Group

Hydrogenations of (4-methylphenyl)trimethylsilane, [4-(trifluoromethyl)phenyl]trimethylsilane, and 1,4-bis(trimethylsilyl)benzene provide the corresponding predominantly cis (∼80%) 4-substituted cyclohexyltrimethylsilanes on the basis of H, C, and F nuclear magnetic resonance spectra. These spectra, and in particular the low-temperature F spectra of cis-[4-(trifluoromethyl)cyclohexyl]trimethylsilane, require the conclusion that the conformational A value for the trimethylsilyl group is essentially the same as that of trifluoromethyl, viz., 2.4–2.6 kcal/mol

Background levels of bromide in human blood

A total of 183 random, whole-blood specimens was collected from healthy individuals within the State of Queensland (Australia), and the bromide concentration was determined by wavelength-dispersive X-ray fluorescence spectrometry (WDXRF). The intensity of the tube Compton scatter line was used to account for differences in matrices between the aqueous calibration standard and whole-blood specimens. Technical details of the WDXRF method are included in the experimental section of the paper. The overall mean for bromide in human blood was 5.3 ± 1.4 mg/L and ranged from 2.5 to 11.7 mg/L. Associations between bromide levels and variables including age, gender, weight, height, and postcode address were examined by ANOVA and Pearson's correlation. Data indicate that aged persons (45–65+ years) are more likely to have higher bromide levels than younger persons (15–25 years). Our results also suggest differences in bromide levels between the sexes in similar age groups. Average levels were higher in females in most age groups. The reason for this difference requires further detailed investigation. No correlation was observed between bromide levels and height or weight of donors. No significant differences in bromide levels were found in persons living in the highly populated southeast region of Queensland compared with those living in the less urbanized northern parts of the state

Background Levels of Bromide in Human Blood

A total of 183 random, whole-blood specimens was collected from healthy individuals within the State of Queensland (Australia), and the bromide concentration was determined by wavelength-dispersive X-ray fluorescence spectrometry (WDXRF). The intensity of the tube Compton scatter line was used to account for differences in matrices between the aqueous calibration standard and whole-blood specimens. Technical details of the WDXRF method are included in the experimental section of the paper. The overall mean for bromide in human blood was 5.3 ± 1.4 mg/L and ranged from 2.5 to 11.7 mg/L. Associations between bromide levels and variables including age, gender, weight, height, and postcode address were examined by ANOVA and Pearson's correlation. Data indicate that aged persons (45–65+ years) are more likely to have higher bromide levels than younger persons (15–25 years). Our results also suggest differences in bromide levels between the sexes in similar age groups. Average levels were higher in females in most age groups. The reason for this difference requires further detailed investigation. No correlation was observed between bromide levels and height or weight of donors. No significant differences in bromide levels were found in persons living in the highly populated southeast region of Queensland compared with those living in the less urbanized northern parts of the state

Some group IVB derivatives of 1,6-methano[10]annulene. Synthesis, substituent effects and reactivity

Certain Group IVB derivatives of 1,6-methano[10]annulene have been synthesised, and their C nuclear magnetic resonance spectra recorded and assigned, to provide a measure of the substituent effects exerted by metalloid-containing groups in this non-benzenoid aromatic system. Comparisons are made with the corresponding naphthalene and some anthracene derivatives. Protiodemetallations of a number of arylsilanes and -stannanes have been examined, and in protiodestannylation by CHCOH/dioxane at 27°C (an electrophilic aromatic substitution) the α- (or 2-) position of 1,6-methano[10]annulene is ca. 35 times as reactive as the α (or 1-) position of naphthalene, whereas in protiodesilylation by CFCOH/CHCOH at 27°C it is ca. 700 times the more reactive

Background levels of bromide in human blood

A total of 183 random, whole-blood specimens was collected from healthy individuals within the State of Queensland (Australia), and the bromide concentration was determined by wavelength-dispersive X-ray fluorescence spectrometry (WDXRF). The intensity of the tube Compton scatter line was used to account for differences in matrices between the aqueous calibration standard and whole-blood specimens. Technical details of the WDXRF method are included in the experimental section of the paper. The overall mean for bromide in human blood was 5.3 ± 1.4 mg/L and ranged from 2.5 to 11.7 mg/L. Associations between bromide levels and variables including age, gender, weight, height, and postcode address were examined by ANOVA and Pearson's correlation. Data indicate that aged persons (45-65+ years) are more likely to have higher bromide levels than younger persons (15-25 years). Our results also suggest differences in bromide levels between the sexes in similar age groups. Average levels were higher in females in most age groups. The reason for this difference requires further detailed investigation. No correlation was observed between bromide levels and height or weight of donors. No significant differences in bromide levels were found in persons living in the highly populated southeast region of Queensland compared with those living in the less urbanized northern parts of the state.</p