Mercury in hair and blood from residents of Phnom Penh (Cambodia) and possible effect on serum hormone levels

High concentration of mercury (Hg) in hair has been reported for Cambodians. To confirm the Hg contamination occurring through intake, Hg concentrations were determined in both hair and blood of residents (n=20) from Phnom Penh, Cambodia. Mercury concentrations in the hair and blood were 0.69-190microg g(-1) dry wt and 5.2-58microg l(-1), respectively, which were lower than those from Hg contaminated or high fish intake regions, but were higher than those from non-contaminated regions. Some female subjects had hair and blood Hg levels exceeding the threshold values for neurotoxic effects. Interestingly, serum estrone and estradiol levels were positively correlated with blood Hg level for both males and females, indicating possible induction of female hormones by Hg exposure in Cambodians.     

Enhanced bioleaching of copper from circuit boards of computer waste by Acidithiobacillus ferrooxidans

Environmental Chemistry Letters - Computer circuit boards are a major electronic waste containing higher concentrations of copper, gold and silver. These metals may be recovered by bioleaching, an...     

Mercury contamination in human hair and fish from Cambodia: levels, specific accumulation and risk assessment

Mercury (Hg) concentrations in human hair and fish samples from Phnom Penh, Kien Svay, Tomnup Rolork and Batrong, Cambodia, collected in November 1999 and December 2000 were determined to understand the status of contamination, and age- and sex-dependent accumulation in humans and to assess the intake of mercury via fish consumption. Mercury concentrations in human hair ranged from 0.54 to 190mug/g dry wt. About 3% of the samples contained Hg levels exceeding the no observed adverse effects level (NOAEL) of WHO (50mug/g) and the levels in some hair samples of women also exceeded the NOAEL (10mug/g) associated with fetus neurotoxicity. A weak but significant positive correlation was observed between age and Hg levels in hair of residents. Mercury concentrations in muscle of marine and freshwater fish from Cambodia ranged from <0.01 to 0.96mug/g wet wt. Mercury intake rates were estimated on the basis of the Hg content in fish and daily fish consumption. Three samples of marine fish including sharp-tooth snapper and obtuse barracuda, and one sample of sharp-tooth snapper exceeded the guidelines by US EPA and by Joint FAO/WHO Expert Committee on Food Additives (JECFA), respectively, which indicates that some fish specimens examined (9% and 3% for US EPA and JECFA guidelines, respectively) were hazardous for consumption at the ingestion rate of Cambodian people (32.6g/day). It is suggested that fish is probably the main source of Hg for Cambodian people. However, extremely high Hg concentrations were observed in some individuals and could not be explained by Hg intake from fish consumption, indicating some other contamination sources of Hg in Cambodia.     

Urinary 8-hydroxy-2'-deoxyguanosine in inhabitants chronically exposed to arsenic in groundwater in Cambodia

Arsenic concentrations in hair and urine, and urinary levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative DNA damage, were examined for inhabitants of the Mekong Basin in Kratie Province, Cambodia. Also, the arsenic levels of tube-well water were determined. Total arsenic concentrations in tube-well water ranged from <1 to 886 microg L(-1), and 44.8% of these exceeded the WHO drinking water guideline of 10 microg L(-1). Elevated levels of arsenic were observed in the human hair and urine, and also a significant positive correlation was observed between the concentrations in hair and urine. These results suggest that the inhabitants are chronically exposed to arsenic through drinking the tube-well water. Levels of urinary 8-OHdG were higher for the subjects with higher arsenic levels in hair and urine, suggesting that induction of oxidative DNA damage was caused by chronic exposure to arsenic in tube-well water for the inhabitants in Kratie Province. To our knowledge, this is the first report on the oxidative DNA damage caused by chronic exposure to arsenic in groundwater for the inhabitants in Cambodia.     

Organohalogen compounds in human breast milk from mothers living in Payatas and Malate, the Philippines: Levels, accumulation kinetics and infant health risk

Human breast milk samples (n = 33) from primipara and multipara mothers from Payatas a waste dump site, and Malate a reference site in the Phillipines were collected in 2004 and analyzed for eight organohalogen compounds, viz., PCBs, DDTs, CHLs, HCHs, HCB, TCPMe, PBDEs and HBCDs. DDTs and PCBs were predominant in all the samples. Overall mean concentrations of PBDEs found in our study were higher (7.5 ng/g lipid wt.) than those reported for Japan and many other Asian countries. Primipara mothers had significantly higher levels of DDTs, CHLs and HCHs than multipara mothers, but not PBDEs and HBCDs. A few individuals accumulated CHLs close to or even higher than the tolerable daily intake guidelines proposed by Health Canada.     

Persistent organic pollutants in breast milk of mothers residing around an open dumping site in Kolkata,India: Specific dioxin-like PCB levels and fish as a potential source

Concentrations of persistent organic pollutants (POPs) such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and organochlorine pesticides were measured in human breast milk collected from mothers residing near an open dumping site and a reference site in Kolkata, India during 2004–2005. POPs were detected in all the human milk samples analyzed, suggesting that residents of Kolkata are widely exposed to these contaminants. Concentrations of dioxin-like PCBs in the samples from the dumping site were significantly higher than in the reference site samples, whereas no such difference was found for PCDDs and PCDFs. In addition, significantly higher concentrations of total PCBs were also observed in the samples from the dumping site than the reference site. Interestingly, concentrations of total and dioxin-like PCBs in the breast milk of mothers from the dumping site significantly increased with the number of years of residence near the dumping site. These results indicate that significant pollution sources of PCBs are present in the dumping site of Kolkata and the residents living around are exposed to relatively higher levels of PCBs. When the residue levels of dioxins and related compounds in fish collected from ponds near the Kolkata dumping site and the reference site were measured, it was found that dioxin-like PCB and TEQ levels in fish from the dumping site were notably higher than those from the reference site. This result indicates that fish is a potential source of PCBs for residents living near the Kolkata dumping site.     

Contamination by arsenic and other trace elements in tube-well water and its risk assessment to humans in Hanoi, Vietnam

Concentrations of As and other trace elements and their association were examined in groundwater (n = 25) and human hair (n = 59) collected at Gia Lam District and Thanh Tri District, suburban areas of Hanoi, Vietnam, in September 2001. Concentrations of As in the groundwater ranged from <0.10 to 330 microg/l, with about 40% of these exceeding WHO drinking water guideline of 10 microg/l. Also, 76% and 12% of groundwater samples had higher concentrations of Mn and Ba than WHO drinking water guidelines, respectively. Arsenic concentrations in hair of residents in Gia Lam and Thanh Tri Districts (range 0.088-2.77 microg/g dry wt.) were lower than those in other As-contaminated areas of the world, but were higher than those of people in non-contaminated areas. Concentrations of As and Mn in hair of some individuals from the Gia Lam and Thanh Tri Districts exceeded the level associated with their toxicity and, therefore, a potential health risk of As and Mn is a concern for the people consuming the contaminated water in this area. Cumulative As exposure was estimated to be lower than the threshold levels at the present, which might explain the absence of manifestations of chronic As poisoning and arsenicosis in the residents of Gia Lam and Thanh Tri Districts. To our knowledge, this study revealed for the first time that the residents are exposed not only to As but also Mn and Ba from groundwater in the Red River Delta, Vietnam.     

Global pollution monitoring of polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs) and coplanar polychlorinated biphenyls (coplanar PCBs) using skipjack tuna as bioindicator

In order to elucidate the global distribution of dioxins and related compounds, such as PCDDs, PCDFs and coplanar PCBs, levels of these compounds were determined in the muscle of skipjack tuna (Katsuwonus pelamis) collected from the offshore waters and open seas near Japan, Taiwan, Philippines, Indonesia, Seychelles and Brazil, and the Japan Sea, the East China Sea, the South China Sea, the Indian Ocean and the North Pacific Ocean. PCDDs, PCDFs and coplanar PCBs were detected in almost all the specimens collected from all the locations surveyed, indicating widespread contamination by these compounds in the marine environment. Higher concentrations of dioxins and coplanar PCBs were detected in the samples from temperate Asian regions, plausibly due to larger usage and anthropogenic generation in highly industrialized countries around the East China Sea and the South China Sea, such as Japan, Korea, Taiwan, Hong Kong and coastal China.     

Non-metallic organic dyes as photosensitizers for dye-sensitized solar cells: a review

Environmental Science and Pollution Research - The advent of novel technologies has led to the need for environmental and economic integration. Energy consumption plays a vital role in human...