[Estimation on the HIV-1 incidence in Liangshan Yi Autonomous Prefecture, under BED-capture enzyme immunoassay, from 2011 to 2013].

OBJECTIVE: This paper aimed to analyze the situation of HIV infection in Liangshan Yi Autonomous, including HIV recent rate of infection and the ongoing strategies on prevention of the disease in this prefecture. METHODS: Surveillance data on population size, medical institutions, from 2011 to 2013 in Liangshan prefecture was collected. The total numbers of people living in the areas appeared as 412 608, 393 699 and 443 025 from the above mentioned three years. The overall numbers of people living with HIV/AIDS were 4 480, 3 999 and 4 719 respectively in the three years of observation, using the ELISA and WB blot. We also used the ELISA, and Western blotting methods to find out the HIV-positive individuals. We then applied the ' BED HIV-1 incidence capture enzyme immunoassay (BED-CEIA)' on these HIV-positive individuals to locate those who were recently infected, to estimate the annual recent infection rates. RESULTS: The HIV-positive rates in Liangshan Prefecture appeared as 1.09%, 1.02% and 1.07% respectively, from 2011 to 2013, with the recent infection rates as 0.34% (95%CI: 0.32-0.37), 0.62% (95%CI: 0.58-0.66) and 0.61% (95%CI: 0.57-0.65) respectively. The newly infections mainly involved with males, with Yi ethnicity, married, being illiterate or received primary school education. In males, the rates of infection appeared as 64.24% (433/674), 59.22% (504/851) and 58.37% (495/848) respectively, in the three years of observation among people with Yi ethnicity, the recent infection rates were 84.72% (571/674) in 2011, 94.59% (805/851) in 2012 and 84.20% (714/848) in 2013. The rates seen in married people were 61.57% (415/674), 61.45% (523/851) and 60.50% (513/848) respectively. Among the illiterates or people only received primary school education, the rates appeared as 60.24% (406/674) in 2011, 61.57% (524/851) in 2012, and 60.03% (509/848) in 2013. CONCLUSION: Using the HIV recent infection rate to describe the situation of AIDS in Liangshan prefecture, figures seemed to be more reliable than under the regular HIV-positive rate.

Control of an outbreak due to orthopedic infections caused by Enterobacteriaceae producing IMP-4 or IMP-8 carbapenemases.

OBJECTIVE: To investigate control of an outbreak due to orthopedic infections caused by Enterobacteriaceae producing IMP carbapenemases. METHODS: The sporadic orthopedic infections with Enterobacteriaceae producing carbapenemase (CPE) were retrospectively analyzed in a Chinese tertiary care hospital from November 2010 to September 2012. RESULTS: The CPE were isolated from four distinct orthopedic patients, three patients infected with Enterobacter cloacae while the other with Klebsiella oxytoca. All strains were resistant to almost all the conventional antimicrobial. The strains produced IMP-4 type detected in the two early patients, while other strains could produce IMP-8 type. All of the four patients had ever undergoing invasive surgical procedure, and three of them were given fluoroquinolones for anti-infection treatment while the other patients was treated with meropenem. Ultimately, all patients were cured and discharged, without outbreak of nosocomial infection caused by CPE. CONCLUSION: Our study shows that strict infection control plays an important role in limiting dissemination of Enterobacteriaceae producing IMP carbapenemase. In addition, reasonable supporting treatment and disinfection protection seems to be more effective for the infection of strains.

Residues of organochlorine pesticides in Hong Kong soils.

It was short of research on the organochlorine pesticides (OCPs) residues in the soils of Hong Kong. Sixty-six representative soil samples were collected from the 46 sites covering five types of land uses in Hong Kong. Hexachlorohexanes (HCH) and 7 Stockholm Convention OCPs were analyzed by gas chromatograph (GC) equipped with a Nickel 63 electronic capture detector (muECD). The results presented that HCH and 5 Stockholm Convention pesticides were detected in Hong Kong soils although the detectable ratio varies to a great extent. The concentration sequence of the five detectable OCPs was HCH > dichlorodiphenyltrichloroethane (DDT) > hexachlorobenzene (HCB) approximately = Endrin > alpha-endosulfan. Among the OCPs and their homologues or isomers, beta-HCH and p,p'-DDE were the two predominant substances according to the concentrations and detectable ratios, concentrations of which in soils were averagely 6.12 microg kg(-1) and 0.41 microg kg(-1) respectively. Soil horizon samples of 0-10 cm, 10-30 cm and >30 cm depth were selected from nine soil profiles to demonstrate the depth distributions of DDT and HCH in soil profiles. Concentrations of HCH tended to increase gradually from the topsoil to bottom layer while the lowest concentration of DDT is usually found in the subsoil (10-30 cm) in most sampling sites. In addition, close correlations of pH(KCl) and total organic carbon (TOC) with HCH indicated an effect on the residues of HCH caused by these two soils properties, but such relationships were not found with DDT or other OCPs.

Distributions and concentrations of PAHs in Hong Kong soils.

Surface soil (0-10 cm) samples from 53 sampling sites including rural and urban areas of Hong Kong were collected and analyzed for 16 EPA priority polycyclic aromatic hydrocarbons (PAHs). Total PAH concentrations were in the range of 7.0-410 microg kg(-1) (dry wt), with higher concentrations in urban soils than that in rural soils. The three predominant PAHs were Fluoranthene, Naphthalene and Pyrene in rural soils, while Fluoranthene, Naphthalene and Benzo(b + k)fluoranthene dominated the PAHs of urban soils. The values of PAHs isomer indicated that biomass burning might be the major origin of PAHs in rural soils, but vehicular emission around the heavy traffic roads might contribute to the soil PAHs in urban areas. A cluster analysis was performed and grouped the detectable PAHs under 4 clusters, which could be indicative of the PAHs with different origins and PAHs affected by soil organic carbon contents respectively.

Effects of cadmium on nutrient uptake and translocation by Indian Mustard.

Plants that hyperaccumulate metals are ideal subjects for studying the mechanisms of metal and mineral nutrient uptake in the plant kingdom. Indian Mustard (Brassica juncea) has been shown to accumulate moderate levels of Cd, Pb, Cr, Ni, Zn, and Cu. In this experiment, 10 levels of Cd concentration treatments were imposed by adding 10-190 mg Cd kg(-1) to the soils as cadmium nitrate [Cd(NO3)2]. The effect of Cd on phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and the micronutrients iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) in B. juncea was studied. Plant growth was affected negatively by Cd, root biomass decreased significantly at 170 mg Cd kg(-1) dry weight soils treatment. Cadmium accumulation both in shoots and roots increased with increasing soil Cd treatments. The highest concentration of Cd was up to 300 mg kg(-1) d.w. in the roots and 160 mg kg(-1) d.w. in the shoots. The nutrients mainly affected by Cd were P, K, Ca, Fe, and Zn in the roots, and P, K, Ca, and Cu in the shoots. K and P concentrations in roots increased significantly when Cd was added at 170 mg kg(-1), and this was almost the same level at which root growth was inhibited. Zn concentrations in roots decreased significantly when added Cd concentration was increased from 50 to 110 mg kg(-1), then remained constant with Cd treatments from 110 to 190 mg kg(-1). However, Zn concentrations in the shoots seemed less affected by Cd. It is possible that Zn uptake was affected by the Cd but not the translocation of Zn within the plant. Ca and Mg accumulation in roots and shoots showed similar trends. This result indicates that Ca and Mg uptake is a non-specific process.

Novel use of soil moisture samplers for studies on anaerobic ammonium fluxes across lake sediment-water interfaces.

Small soil suction samplers have been used for several years to sample soil solution for chemical analysis in laboratory and glasshouse experiments. They are very cheap, effective and convenient. Here we describe for the first time their use in studies on sediment porewater. Bulk sediment from West Lake, a shallow hypereutrophic lake in Hangzhou, Zhejiang Province, China, was placed in laboratory microcosms and incubated in the dark at 25 degrees C for 182 days to evaluate the feasibility of using the samplers to extract sediment porewater and to estimate NH4+ flux across the sediment-water interface under anaerobic conditions. The results show that the samplers were capable of sequentially extracting sediment porewater, 15 ml of which could be readily extracted for analysis within 30-45 min by vacuum applied using a plastic syringe. The NH4+ flux under laboratory conditions was characterized by a fast phase during the initial 18 days of incubation followed by a slower linear phase, with average release rates of 11.6 and 3.6 mg N m(-2) d(-1), respectively.

Soil Cd availability to Indian mustard and environmental risk following EDTA addition to Cd-contaminated soil.

A pot experiment was conducted to investigate the influence of EDTA on the extractability of Cd in the soil and uptake of Cd by Indian mustard (Brassica juncea). Twenty levels of soil Cd concentration ranging from 10 to 200 mg kg(-1) were produced by spiking aliquots of a clay loam paddy soil with Cd(NO3)2. One week before the plants were harvested EDTA was applied to pots in which the soil had been spiked with 20, 40, 60...200 mg Cd kg(-1). The EDTA was added at the rate calculated to complex with all of the Cd added at the 200 mg kg(-1) level. Control pots spiked with 10, 30, 50... 190 mg Cd kg(-1) received no EDTA. The plants were harvested after 42 days' growth. Soil water- and NH4NO3-extractable Cd fractions increased rapidly following EDTA application. Root Cd concentrations decreased after EDTA application, but shoot concentrations increased when the soil Cd levels were >130 mg kg(-1) and Cd toxicity symptoms were observed. The increases in soil solution Cd induced by EDTA did not increase plant total Cd uptake but appeared to stimulate the translocation of the metal from roots to shoots when the plants appeared to be under Cd toxicity stress. The results are discussed in relation to the possible mechanisms by which EDTA may change the solubility and bioavailability of Cd in the soil and the potential for plant uptake and environmental risk due to leaching losses to groundwater.

Changes in soil microbial biomass and Zn extractability over time following zn addition to a paddy soil.

A laboratory incubation study was conducted using a paddy soil spiked with two quantities of Zn as soluble Zn(NO3)2 and unamended controls. Three single extractants (1 M ammonium acetate (pH 7.0), 0.43 M acetic acid and 0.05 M EDTA) were used to assess the bioavailability of Zn. Biological community assessments were made microbial biomass (chloroform fumigation), soil basal respiration and dehydrogenase activity. During the 84-day period of the experiment, addition of Zn at both 500 and 1,000 mg kg(-1) had little detectable effect on soil pH. The concentration of NH4OAc-extractable Zn decreased rapidly within the initial six weeks. The concentration of HOAc-extractable Zn showed no decrease during 84 days incubation. EDTA-extractable Zn was greater than NH4OAc- and HOAc-extractable fractions, and showed a similar trend to NH4OAc-extractable after incubation. Microbial biomass, soil basal respiration and dehydrogenase activity all decreased over time during 84 days incubation. Addition of Zn resulted in a significant increase in specific respiration (qCO2). Microbial biomass and dehydrogenase activity did not appear to be influenced by added Zn, probably due to the strong buffering capacity of the soil. The Zn extracted by EDTA, HOAc and NH4OAc showed close relationships with each other (p < 0.001). Zinc extracted by 0.05 M EDTA and NH4OAc were highly correlated with soil basal respiration and specific respiration rate (p < 0.01). The results suggest that NH4OAc-extractable Zn combined with soil specific respiration could be used as parameters for risk assessment.