The pollution and ecological risk of endosulfan in soil of Huai’an city, China

Endosulfan, a persistent organic pollutant newly listed under the Stockholm Convention, is currently widely produced and used as a pesticide in China. Concentrations of endosulfans (including α-, β-isomers, and their metabolite endosulfan sulfate) were determined in surface soil collected from Huai’an city, where the largest endosulfan producer is located. The concentrations of Σendosulfan (sum of α-endosulfan, β-endosulfan, and endosulfan sulfate) at all sites ranged from 0.28 to 44.81?ng/g dry weight (dw), following a lognormal distribution. The geometric mean was 1.09?ng/g dw, and the geometric standard deviation was 3.02. The β-endosulfan levels were consistently greater than those of α-isomer. The concentration ratios of α-endosulfan to β-endosulfan ranged from 0.03 to 0.70, which were much lower than the commercial endosulfan mixture. This is because that α-endosulfan is more volatile and degrades faster than β-endosulfan in soil. The contour map of Σendosulfan levels in soil indicates that the factory was the point pollution source with the highest endosulfan level in its surrounding area, especially the southern area. However, the non-point agricultural sources are more important. Based on Monte Carlo simulation, the Σendosulfan inventory in soil in Huai’an is estimated to be 0.8–3.0 tons. In order to understand the potential ecological risk of endosulfan, the Monte Carlo-based hazard quotient distribution was estimated and showed that Σendosulfan posed a potentially high risk to soil organisms. To our knowledge, this study is the first that reports soil pollution and risk of endosulfan around the manufacturer in China. This study will help China’s implementation of Stockholm Convention for the reduction and elimination of endosulfan in future.     

Measurement of natural radioactive nuclide concentrations in various metal ores used as industrial raw materials in Japan and estimation of dose received by workers handling them

Natural resources such as ores and rocks contain natural radioactive nuclides at various concentrations. If these resources contain high concentrations of natural radioactive nuclides, workers handling them might be exposed to significant levels of radiation. Therefore, it is important to investigate the radioactive activity in these resources. In this study, concentrations of radioactive nuclides in Th, Zr, Ti, Mo, Mn, Al, W, Zn, V, and Cr ores used as industrial raw materials in Japan were investigated. The concentrations of ²³⁸U and ²³²Th were determined by inductively coupled plasma mass spectrometry (ICP-MS), while those of ²²⁶Ra, ²²⁸Ra, and ⁴⁰K were determined by gamma-ray spectrum. We found the concentrations of ²³⁸U series, ²³²Th series, and ⁴⁰K in Ti, Mo, Mn, Al, W, Zn, V, and Cr ores to be lower than the critical values defined by regulatory requirements as described in the International Atomic Energy Agency (IAEA) Safety Guide. The doses received by workers handling these materials were estimated by using methods for dose assessment given in a report by the European Commission. In transport, indoor storage, and outdoor storage scenarios, an effective dose due to the use of Th ore was above 4.3 × 10⁻² Sv y⁻¹, which was higher than that of the other ores. The maximum value of effective doses for other ores was estimated to be about 4.5 × 10⁻⁴ Sv y⁻¹, which was lower than intervention exemption levels (1.0 × 10⁻³ Sv y⁻¹) given in International Commission of Radiological Protection (ICRP) Publication 82.     

Transformation of microflora during degradation of gaseous toluene in a biofilter detected using PCR-DGGE

A laboratory-scale biofiltration system, the rotatory-switching biofilter (RSB), was operated for 199 days using toluene as a model pollutant. The target gaseous pollutant for the biofiltration experiment was approximately 300 ppmv of toluene. Toluene removal efficiency (RE, %) was initially approximately 20% with a 247-ppmv concentration (0.9 g m(-3)) of toluene during the first 10 days. Although the RE decreased several times whenever nitrogen was consumed, it again reached almost 100% when the nitrogen source was in sufficient supply. Denaturing gradient gel electrophoresis (DGGE) analysis was employed to assess the transformation ofmicroflora during operation of the biofilter The results based on a 16S rRNA gene profile showed that the microbial community structure changed with operation time. Although the microflora changed during the initial period (before day 40), transformation of the bacterial component was hardly observed after day 51. Statistical analyses of the DGGE profiles indicated that the bacterial community was almost unaffected by the environmental factors, such as adding ozone, high-level nitrogen supply, increase of loading toluene, and the shutdown of the RSB. The DGGE profile using tmoA-like genes, which encode proteins belonging to the hydroxylase component mono-oxygenases involved in the initial attack of aerobic benzene, toluene, ethylbenzene, and xylene degradation, confirmed the existence of toluene-degrading bacteria. There were at least four kinds of toluene-degradable bacteria having tmoA-like genes up to day 36, which decreased to two species after day 40. Sequence analysis after DGGE profiling revealed that Burkholderia cepacia, Sphingobacterium multivorum, and Pseudomonas putida were present in the biofilter. Only Alicycliphilus denitrificans was present throughout the whole operation period. In the initial stage of operating the RSB, many types of bacteria may have tried to adapt to the conditions, and subsequently, only selected bacteria were able to grow and to degrade toluene.     

Polychlorinated dibenzo-p-dioxins and dibenzofurans in invertebrate animals from a rural beach in Japan

PCDDs and PCDFs were analyzed by high resolution GC MS in several invertebrate animals collected from a rural beach in Japan. PCDDs and PCDFs were detected in all samples. Total concentration of PCDDs and PCDFs ranged 8.8–120 pg g⁻¹ wet and 3.5–38 pg g⁻¹ wet, respectively. TEQs of invertebrate animals examined ranged from 0.048 pg g⁻¹ wet in sea slug to 0.91 pg g⁻¹ wet in mussel. Isomer profiles in all samples were similar to each other despite of variety of species. Their major sources are estimated to be herbicides such as CNP and PCP, and combustion by using a statistical analysis of isomer profiles.     

Detoxification of hexachlorobenzene by dechlorination with potassium-sodium alloy

Dechlorination of hexachlorobenzene (HCB) was achieved by a liquid potassium–sodium (K–Na)-alloy. HCB in a cyclohexane/benzene solution (22 mmol/l, 4.67 g/l as chlorine) was dechlorinated by almost 100% after a 30-min reaction, indicating high reactivity of K–Na alloy and high proton donating power of cyclohexane. Decreasing orders of chlorobenzenes identified after a 15-min reaction, by amount were 1,2,3,4- > 1,2,3,5- > 1,2,4,5- for tetrachlorobenzenes, 1,2,4- > 1,2,3- > 1,3,5- for trichlorobenzenes, and 1,4- > 1,3- > 1,2- for dichlorobenzenes. It was hypothesized that once one chlorine atom in HCB was replaced with a proton, the adjacent chlorine atom to the proton tended to be replaced with another hydrogen atom. A total of 63 PCBs formed via the Wurtz–Fittig reaction were identified as by-products in the sample after a 15-min reaction. Among PCBs found, 2,3^′,4^′,5-tetrachlorobiphenyl, which was a product from 1,2,4-trichlorobenzene formed via the Wurtz–Fittig reaction, was detected in relatively high concentration (48.9 nmol/ml). The sample obtained from a reaction mixture after 30 min contained only 14 PCBs in trace amounts, indicating that the PCBs formed were also further dechlorinated by K–Na alloy. Non-chlorinated compounds––such as methylbenzene, dimethylbenzene, dimer of tetrahydrofuran, and dicyclohexyl (dimer of cyclohexane)––were also identified in the samples. A method using K–Na alloy developed in the present study dechlorinated satisfactorily HCB at room temperature.     

Horizontal distribution of steroid estrogens in surface sediments in Tokyo Bay

A monitoring survey was conducted to investigate the distribution of steroid estrogens and their conjugates in surface sediments of Tokyo Bay for the first time, which is known as one of the most heavily polluted marine embayments in the world. The surface sediment samples were collected at 20 locations covering the whole area of Tokyo Bay and analyzed for steroid estrogens and their conjugates using liquid chromatography-tandem mass spectrometry. The concentrations of 17beta-estradiol (beta-E2) and estrone (E1) ranged from ND (below the detection limit; <0.07) to 0.59 and from 0.05 to 3.60 ng g-1 dry, respectively. Those concentrations were higher in the northern part of the bay, which is directly receiving huge quantities of pollutants from adjacent rivers containing a large amount of municipal and industrial wastewater. 17alpha-Estradiol (alpha-E2) and estrone-3-sulfate (E1-3S) were detected in some of the samples, whereas neither of the other conjugates, estriol (E3) or 17alpha-ethynylestradiol (EE2), was found.     

Degradation of fats during thermophilic composting of organic waste.

The degradation of fats during thermophilic composting was investigated by adding lard of four different mixing ratios (0, 33.3, 42.9 and 50% on a dry weight basis) to dog food used as a model substrate for organic waste. The lard added at the mixing ratio of 33.3% did not inhibit the decomposition of organic matter in the dog food, with lard itself beginning decomposition after decay of more easily decomposable organic compounds of the dog food, 84 h from the start of composting. The percentage of lard decomposition reached as high as 29.3% by the end of 8 days of composting. By contrast, the decomposition of organic matter in the processed dog food was apparently inhibited when the portion of lard was greater than 33.3%, especially at the earliest stage of composting. It is possible, however, that lard would decompose vigorously once decomposition has begun, even when the ratio of lard is as high as 50%. The percentages of lard decomposition in composting mixtures with 42.9 and 50% lard were 15.7 and 9.50%, respectively, thus the higher the mixing ratio of lard, the lower the percentage of lard decomposition. However, it was found that the maximum decomposition rate of the lard was similar for all of the ratios tested; that is, approximately 5.0 x 10(-3) g carbon h(-1).     

Feminization of genetic males by a symbiotic bacterium in a butterfly,Eurema hecabe (Lepidoptera: Pieridae)

Wolbachia are symbiotic bacteria found in many arthropods and filarian nematodes. They often manipulate the reproduction of host arthropods. In the present study, female-biased sex-ratio distortion in the butterfly Eurema hecabe was investigated. Breeding experiments showed that this distorted sex ratio is maternally inherited. When treated with tetracycline, adult females of the thelygenic line produced male progeny only. After PCR using Wolbachia-specific primers for the ftsZ gene a positive result was seen in the thelygenic females, but not in male progeny from tetracycline-treated females, or individuals from a Tokyo population with normal sex ratio and reproduction. Cytological observations showed that thelygenic females lack the sex chromatin body (W chromosome). The results strongly suggest that the sex-ratio distortion in E. hecabe is due to feminization of genetic males by Wolbachia.