Polybrominated diphenyl ethers in the soil of typical industrial city

Polybrominated diphenyl ethers (PBDEs) concentration in soil from San Luis Potosi, Mexico: levels and ecological and human health risk characterization

The aim of this study was to assess the levels of polybrominated diphenyl ethers (PBDEs) in soils from the city of San Luis Potosi in Mexico and perform an ecological and human health risk characterization. In order to confirm the presence of PBDEs, outdoor surface soil samples were collected and the concentrations of PBDEs in urban, industrial, agricultural, and brick kiln industry areas were determined. The mean total PBDEs levels obtained in the study sites were 25.0 ± 39.5 μg/kg (geometric mean ± standard deviation) in the brick kiln industry zone; 34.5 ± 36.0 μg/kg in the urban zone; 8.00 ± 7.10 μg/kg in the industrial zone and 16.6 ± 15.3 μg/kg in the agricultural zone. The ecological and human health risk characterization showed relatively low-hazard quotient values. However, the moderately high PBDEs levels found in soils highlight the necessity to establish a systematic monitoring process for PBDEs in environmental and biological samples.

Concentrations of persistent organic pollutants (POPs) and heavy metals in soil from San Luis Potosí, México

The aim of this study was to assess the levels of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), p,p'-dichlorodiphenyltrichloroethane (DDT), p,p'-dichlorodiphenyldichloroethylene (DDE), and four heavy metals (arsenic, cadmium, lead, and mercury) in soil from the city of San Luis Potosí in Mexico. In order to confirm the presence of the previously mentioned compounds, outdoor surface soil samples were collected and analyzed by gas chromatography/mass spectrometer for PBDEs, PCBs, DDT, and DDE. Meanwhile, heavy metals were quantified using the atomic absorption spectrophotometry technique. The total PBDEs levels ranged from 5.0 to 134 μg/kg dry weight (dw), with a total mean PBDEs level of 22.0 ± 32.5 μg/kg dw (geometric mean ± standard deviation). For PCBs, the total mean level in the studied soil was 21.6 ± 24.7 μg/kg dw (range, <LOD to 80.5). An important finding in our study was that all soil samples (100 %) had detectable levels of the metabolite DDE. Moreover, the total mean DDT level (∑ DDT and DDE) was approximately 5.50 ± 4.50 μg/kg dw. The mean levels for arsenic, mercury, cadmium, and lead in soil samples were 7.20 ± 10.7 (range, 15.0 to 265 mg/kg dw), 0.45 ± 0.48 (range, <LOD to 2.50 mg/kg dw), 3.00 ± 3.00 (range, 1.00-13.0 mg/kg dw), and 108 ± 105 (range, 25.0 to 435 mg/kg dw), respectively. This screening study provides us with concentration data for the occurrence of persistent organic pollutants (POPs) and four heavy metals in soil samples from the city of San Luis Potosí, Mexico, and considering that soil is an important pathway of exposure for people, a biomonitoring program for the surveillance of the general population in the city of San Luis Potosi is necessary.

Polybrominated diphenyl ethers (PBDEs) in house dust in Beijing, China

Eleven house dust samples were collected in Beijing to quantify 42 different polybrominated diphenyl ethers (PBDEs). Total PBDEs concentrations ranged from 140 to 1,300 ng g(-1). The dominant PBDEs congener identified was BDE 209, which made up more than 70% of all PBDEs congeners. Concentrations of PBDEs in Chinese house dust were lower than in other countries. The most polluted areas were electronics shops and households. It is likely that PBDEs exposure is a potential threat for Beijing residents, particularly toddlers.

Distribution of polybrominated diphenyl ethers in the surface sediments of the Taihu Lake, China

Twenty-eight sediment samples were collected from the Taihu Lake and analyzed to acquire information about the levels, distribution, possible sources, time trend and inventory of polybrominated diphenyl ethers (PBDEs) in the Taihu Lake. Our results showed that the most abundant BDE congeners in surface sediments were BDE-47, 99 and 209, with a median value of 0.124, 0.279, and 22.72 ng(gdw)(-1), respectively. The levels of BDE-209 in our samples were much higher relative to those of the other BDE congeners and made up more than 80% of the PBDEs levels in almost all samples. Disregarding BDE-209, among the seven PBDEs (BDE-28, 47, 99, 100, 153, 154, 183) more concerned, the most abundant ones were BDE-47 and 99, which contributed 44.65% (ranged from 29.02% to 73.11%), 24.24% (ranged from 2.27% to 39.66%) to ∑(7)PBDEs, respectively. The correlation between PBDE and TOC was poor, indicating that PBDEs concentrations in sediments of the Taihu Lake were controlled not only by TOC contents, but also by a combined effect of transport, mixing, depositional mechanisms associated with PBDEs, uncontaminated sediments, or fresh input of PBDEs. As expected, the time trend of PBDEs concentration in surface sediment from Taihu Lake were increasing, and the inventory of ∑(25)PBDEs and BDE-209 were estimated to be 3668 kg and 26296 kg.

Analysis of emerging organic contaminants in environmental solid samples

Spreading sewage sludge on agricultural lands has been actively promoted by national authorities as an economic way of recycling. However, as by-product of wastewater treatment, sewage sludge may contain toxic substances, which could be incorporated into agricultural products or be distributed in the environment. Moreover, sediments can be contaminated by the discharge of wastewater effluents into rivers. This article reviews the determination of emerging contaminants (surfactants, flame retardants, pharmaceuticals and personal care products) in environmental solid samples (sludge, soil and sediment). Sample preparation, including extraction and clean-up, as well as the subsequent instrumental determination of contaminants are discussed. Recent applications of extraction techniques, such as Soxhlet extraction, ultrasound assisted extraction, pressurised liquid extraction, microwave assisted extraction and matrix solid-phase dispersion to the analysis of emerging contaminants in environmental solid samples are reviewed. Determination of these contaminants, generally carried out by gas chromatography and liquid chromatography coupled with different detectors, especially mass spectrometry for the identification and quantification of residues, is also summarised and discussed.

The cytotoxic effects of synthetic 6-hydroxylated and 6-methoxylated polybrominated diphenyl ether 47 (BDE47)

Polybrominated diphenyl ethers (PBDE) have been widely applied as flame retardants in plastics, polyurethane foam, paints, and synthetic fabrics. The rising PBDE level in human tissues and environment has led to concern about the health impact of exposure to PBDE. The 2,2',4,4'-tetrabromodiphenyl ether (BDE47), the dominant PBDE congener found in the environment and human tissues, has been shown to be an endocrine disruptor. It has also been reported to cause liver and neurodevelopmental toxicity. BDE47 can be metabolized to 6-OH-BDE47 and 6-MeO-BDE47. So far little has been reported on the cytotoxicity of the metabolites. In the present study, the cytotoxicity of the two metabolites was investigated by exposing human hepatoma cell line HepG2 to different doses of 6-OH-BDE47 and 6-MeO-BDE47. The cell viability, cell cycle, apoptosis, DNA damage, micronucleus levels, and oxidative stress response were studied. The results indicated that both metabolites could markedly inhibit the proliferation of HepG2 cells with 6-OH-BDE47 showing a stronger effect, and significantly increase the micronucleus level and apoptosis rate in a dose-dependant manner. Moreover, treatment with 6-OH-BDE47 (≥0.5 μM) resulted in a marked cell cycle block. The SCGE experiments revealed that both metabolites could cause DNA damage in a dose-dependant manner. Analysis of the oxidative stress response showed that 6-OH-BDE47 treatment (≥2.0 μM) significantly increased intracellular ROS levels as indicated by GSH depletion and elevation of SOD level, whereas 6-MeO-BDE47 showed a weaker effect, suggesting that oxidative stress might play a role in the cytotoxic effects. We concluded that 6-OH-BDE47 or 6-MeO-BDE47 exposure was able to induce inhibition of cell viability, increase of apoptosis rate, cell cycle block, and DNA damages, which might involve the alterated oxidative stress response due to the elevated free radicals and impaired antioxidative system.

Occurrence of polybrominated diphenyl ethers in soil from the central Loess Plateau, China: role of regional range atmospheric transport

Very few studies were conducted in highland and depositional areas in studying the transport and behavior of polybrominated diphenyl ethers (PBDEs). In this study, surface soils were collected from Huan County to investigate the level, profile, and potential influence of PBDEs via regional range atmospheric transport in the central part of the Loess Plateau (CLP) of China, one of the most extensive areas of loess deposition in the world. PBDEs were ubiquitous and log-normally distributed in soils from the CLP with mean concentrations of 0.91 and 0.54 ng g(-1) for ΣPBDEs (sum of PBDE congeners except for BDE-209) and BDE-209, respectively. BDE-209 was predominated congener (43.5%), followed by BDE-47 (15.7%), 99 (10.7%), and 153 (7.5%). Further principal component analysis on congener profiles showed that PBDEs in the CLP originated from similar source(s). Additionally, significant differences in the ratios of BDE-47 to 99 and BDE-153 to 154 were found between soil samples and commercial products, indicating that they have undergone fractionation during the process of regional range atmospheric transport. The deposition of PBDEs in the CLP could be influenced by the sources from surrounding regions. For example, Xi'an may have potential influence to the CLP based on geographical analysis and concentrations comparison of PBDEs in gaseous. Therefore, more studies are needed to clarify the atmospheric transport and fate of PBDEs in this region.