Accumulation of trace metals in the embryos and hatchlings of Chelonia mydas from Peninsular Malaysia incubated at different temperatures.

A variety of trace metals were measured in the egg contents of three clutches of Chelonia mydas collected from Kuala Terengganu state in Peninsular Malaysia. We quantified Mn, Cu, Zn, Se (essential trace metals) and As (anthropogenic pollutant) at several developmental stages obtained by incubating eggs at two different temperatures (27 °C and 31 °C). The incubation temperatures were chosen because they produce predominantly male or predominantly female hatchlings, respectively. The eggs were removed from the sand and washed before being placed in incubators, to ensure that the only possible source of the detected metals was maternal transfer. Other metals: Mo, Co, Ni, Cd, Sn, Sb, Hg, Tl and Pb (all non-essential metals) were detected at concentrations below the lower limit of quantitation (LLOQ). Trace metal concentrations, particularly [Zn], increased during development, other metals (Cu, As, Se and Cr) accumulated to a lesser degree than zinc but no significant differences were observed between the incubation temperatures at any stage of incubation. To date, only a few studies on trace metals in turtle embryos and hatchlings have been reported; this study will provide basic knowledge on the accumulation of trace metals during development at two different incubation temperatures.

Trace element concentrations in nesting flatback turtles (Natator depressus) from Curtis Island, Queensland, Australia.

The blood and eggs of the flatback turtle (Natator depressus) sampled when nesting at Curtis Island, Queensland, Australia. In the blood, zinc was present at the highest concentration of 151.15 ± 1.45 µg/L followed by copper (7.74 ± 0.09 µg/L). Lead was found only in some individuals. The measured trace elements in the blood were maternally transferred into the eggs. Other metals and metalloids detected in eggs were chromium, manganese, arsenic and selenium. Eggs showed a more complex trace element profile than blood, suggesting that they provided more representative tissues for determining maternal levels of trace element accumulation in N. depressus. Intra-clutch variation was over 15% for most of the studied trace elements suggesting one egg is not in sufficient to determine trace element accumulation within a clutch. Copper was the only element which was positively correlated with breeding age. Furthermore, no detectable levels of tin compound derivates were measured in N. depressus.

Using blood samples to estimate persistent organic pollutants and metals in green sea turtles (Chelonia mydas).

Persistent organic pollutants (POPs) and heavy metals have been reported in a number of green turtle (Chelonia mydas) populations worldwide. However, due to ethical considerations, these studies have generally been on tissues from deceased and stranded animals. The purpose of this study was to investigate the use of blood samples to estimate the tissue contamination of live C. mydas populations. This study analysed 125 POP compounds and eight heavy metals in the blood, liver, kidney and muscle of 16 C. mydas from the Sea World Sea Turtle Rehabilitation Program, Gold Coast, Australia. Strong correlations were observed between blood and tissue concentrations for a number of POPs and metals. Furthermore, these correlations were observed over large ranges of turtle size, sex and condition. These results indicate that blood samples are a reliable non-lethal method for predicting chemical contamination in C. mydas.

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.

Silver deposits in cutaneous burn scar tissue is a common phenomenon following application of a silver dressing.

BACKGROUND: Silver dressings have been widely and successfully used to prevent cutaneous wounds, including burns, chronic ulcers, dermatitis and other cutaneous conditions, from infection. However, in a few cases, skin discolouration or argyria-like appearances have been reported. This study investigated the level of silver in scar tissue post-burn injury following application of Acticoat, a silver dressing. METHODS: A porcine deep dermal partial thickness burn model was used. Burn wounds were treated with this silver dressing until completion of re-epithelialization, and silver levels were measured in a total of 160 scars and normal tissues. RESULTS: The mean level of silver in scar tissue covered with silver dressings was 136 microg/g, while the silver level in normal skin was less than 0.747 microg/g. A number of wounds had a slate-grey appearance, and dissection of the scars revealed brown-black pigment mostly in the middle and deep dermis within the scar. The level of silver and the severity of the slate-grey discolouration were correlated with the length of time of the silver dressing application. CONCLUSIONS: These results show that silver deposition in cutaneous scar tissue is a common phenomenon, and higher levels of silver deposits and severe skin discolouration are correlated with an increase in the duration of this silver dressing application.

The effect of organochlorines and heavy metals on sex steroid-binding proteins in vitro in the plasma of nesting green turtles, Chelonia mydas.

In this study on green turtles, Chelonia mydas, from Peninsular Malaysia, the effect of selected environmental toxicants was examined in vitro. Emphasis was placed on purported hormone-mimicking chemicals such as dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene, dieldrin, lead, zinc and copper. Five concentrations were used: high (1 mg/L), medium (10(-1) mg/L), low (10(-2) mg/L), very low (10(-6) mg/L) and control (diluted carrier solvent but no toxicants). The results suggest that environmental pesticides and heavy metals may significantly alter the binding of steroids [i.e. testosterone (T) and oestradiol] to the plasma proteins in vitro. Competition studies showed that only Cu competed for binding sites with testosterone in the plasma collected from nesting C. mydas. Dieldrin and all heavy metals competed with oestradiol for binding sites. Furthermore, testosterone binding affinity was affected at various DDT concentrations and was hypothesised that DDT in vivo may act to inhibit steroid-protein interactions in nesting C. mydas. Although the precise molecular mechanism is yet to be described, DDT could have an effect upon the protein conformation thus affecting T binding (e.g. the T binding site on the steroid hormone binding protein molecule).

Silver absorption on burns after the application of Acticoat: data from pediatric patients and a porcine burn model.

Silver dressings have been widely used to successfully prevent burn wound infection and sepsis. However, a few case studies have reported the functional abnormality and failure of vital organs, possibly caused by silver deposits. The aim of this study was to investigate the serum silver level in the pediatric burn population and also in several internal organs in a porcine burn model after the application of Acticoat. A total of 125 blood samples were collected from 46 pediatric burn patients. Thirty-six patients with a mean of 13.4% TBSA burns had a mean peak serum silver level of 114 microg/L, whereas 10 patients with a mean of 1.85% TBSA burns had an undetectable level of silver (<5.4 microg/L). Overall, serum silver levels were closely related to burn sizes. However, the highest serum silver was 735 microg/L in a 15-month-old toddler with 10% TBSA burns and the second highest was 367 microg/L in a 3-year old with 28% TBSA burns. In a porcine model with 2% TBSA burns, the mean peak silver level was 38 microg/L at 2 to 3 weeks after application of Acticoat and was then significantly reduced to an almost undetectable level at 6 weeks. Of a total of four pigs, silver was detected in all four livers (1.413 microg/g) and all four hearts (0.342 microg/g), three of four kidneys (1.113 microg/g), and two of four brains (0.402 microg/g). This result demonstrated that although variable, the level of serum silver was positively associated with the size of burns, and significant amounts of silver were deposited in internal organs in pigs with only 2% TBSA burns, after application of Acticoat.

Fluoride content of powdered infant formula meets Australian Food Safety Standards.

OBJECTIVES: To identify the fluoride content of powdered formula for infants 0-12 months in products available from Brisbane stores in 2006/07 and compare this with the fluoride content of infant formula products available in Australia 10 years earlier. METHODS: A range of available infant formula powders were collected from major supermarkets and chemists in Brisbane, Queensland. The fluoride levels in infant formula powder samples were determined using a modification of the micro-diffusion method of Silva and Reynolds(1) utilising perchloric acid and silver sulphate and measured with an ion selective (fluoride) electrode/meter. Fluoride content both prior to and after reconstitution, as well as estimated daily intake according to age was calculated. RESULTS: Formula samples contained an average of 0.49 microg F/g of powder (range 0.24-0.92 microg F/g). After reconstitution with water containing 0 mg/L fluoride, the fluoride content averaged 7.09 microg F/100mL (range 3.367-22.72 microg F/100mL). Estimated infant fluoride intakes ranged from 0.0039 mg/kg/day for a 6-12 month old infant when reconstituting milk-based formula with non-fluoridated water (0 mg/L), to 0.1735 mg/kg/day for a 0-3 month old infant when reconstituting soy-based formula with fluoridated water (1.0 mg/L). CONCLUSIONS: Infant formula powders contain lower levels of fluoride than previously found in Australia in 1996. IMPLICATIONS: This confirms that infants consume only a small amount of fluoride from milk-based powdered infant formula. Although soy-based infant formulas contain more fluoride than milk-based products, the levels still comply with national food standards.

Public health risks from heavy metals and metalloids present in traditional Chinese medicines.

Out of 247 traditional Chinese medicines (TCM) investigated, a proportion were contaminated with arsenic (5-15%), lead (approximately 5%), and mercury (approximately 65%). Some preparations exceeded the tolerable daily intake (TDI) for males and females for arsenic (4 and 5 products, respectively), lead (1 and 2 products), and mercury (5 and 7 products). These exceedances were as high as 2760-fold, which posed a potential danger to public health. As many users are known to self-prescribe, there is a substantial risk of poisoning from the consumption of these contaminated TCM.