Zhiqun Qiu

Determination of antibiotics in sewage from hospitals, nursery and slaughter house, wastewater treatment plant and source water in Chongqing region of Three Gorge Reservoir in China

Sewage samples from 4 hospitals, 1 nursery, 1 slaughter house, 1 wastewater treatment plant and 5 source water samples of Chongqing region of Three Gorge Reservoir were analyzed for macrolide, lincosamide, trimethoprim, fluorouinolone, sulfonamide and tetracycline antibiotics by online solid-phase extraction and liquid chromatography-tandem mass spectrometry. Results showed that the concentration of ofloxacin (OFX) in hospital was the highest among all water environments ranged from 1.660 microg/L to 4.240 microg/L and norfloxacin (NOR, 0.136-1.620 microg/L), ciproflaxacin (CIP, ranged from 0.011 microg/L to 0.136 microg/L), trimethoprim (TMP, 0.061-0.174 microg/L) were commonly detected. Removal range of antibiotics in the wastewater treatment plant was 18-100% and the removal ratio of tylosin, oxytetracycline and tetracycline were 100%. Relatively higher removal efficiencies were observed for tylosin (TYL), oxytetracycline (OXY) and tetracycline (TET)(100%), while lower removal efficiencies were observed for Trimethoprim (TMP, 1%), Epi-iso-chlorotetracycline (EICIC, 18%) and Erythromycin-H(2)O (ERY-H(2)O, 24%). Antibiotics were removed more efficiently in primary treatment compared with those in secondary treatment.

Effects of arsenic exposure from drinking water on spatial memory, ultra-structures and NMDAR gene expression of hippocampus in rats

Epidemiological investigations indicate that chronic arsenic exposure can damage neurobehavioral function in children. The present study was aimed to study the effects of arsenic exposure from drinking water on the spatial memory, and hippocampal ultra-structures and N-methyl-d-aspartate receptor (NMDAR) gene expression in rats. Sprague-Dawley rats were assigned to four groups: rats in control group drank regular water, rats in other groups drank water with final arsenic concentration of 2.72 mg/L (group A), 13.6 mg/L (group B) and 68 mg/L (group C), respectively, for 3 months. The levels of arsenic in blood serum and hippocampus were monitored. Rats were tested in Morris water maze (MWM) for memory status. Samples of hippocampus were collected from two rats in each group for transmission electron microscopic study and the detection of NMDAR expression by RT-PCR. The rats in group C showed a significant delay in hidden platform acquisition. Neurons and endothelial cells presented pathological changes and the expression of NR2A was down-regulated in hippocampus in arsenic exposed rats. Our data indicated that arsenic exposure of 68 mg/L caused spatial memory damage, of which the morphological and biochemical bases could be the ultra-structure changes and reduced NR2A expression in hippocampus.

A cross-sectional investigation of chronic exposure to microcystin in relationship to childhood liver damage in the Three Gorges Reservoir Region, China.

Background: Microcystin-producing Microcystis bloom is a severe water problem in the world. Some reports indicate that chronic exposure to microcystin may result in liver damage in adults, but information on effects in children is limited. Objective: We investigated the relationship between microcystin exposure and liver damage in children. Methods: We measured microcystin concentrations in drinking water and aquatic food (carp and duck) from two lakes and four wells. Participants were 1,322 children 7–15 years of age who obtained drinking water from one of the tested sources, completed questionnaires, and provided blood samples for serum liver enzymes [alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and γ-glutamyltransferase (GGT)] and serum microcystin analysis. Multivariable logistic regression was used to identify risk factors associated with liver damage (two or more abnormal serum enzyme levels in ALT, AST, ALP, or GGT). Results: Microcystin was detected in most samples of water and aquatic food from two lakes. Children who drank water from the lake with the highest microcystin concentrations had a total estimated daily microcystin intake of 2.03 μg, a value much higher than the tolerable daily intake (0.40 μg) proposed by the World Health Organization for children. Hepatitis B virus (HBV) infection, use of hepatotoxic medicines, and microcystin exposure were associated with liver damage. AST and ALP levels were significantly higher in high-microcystin-exposed children than in low-exposed children and unexposed children when participants who were HBV-positive or hepatotoxic medicine users were excluded from the analysis. Conclusion: These results suggest that chronic exposure to microcystin may be associated with liver damage in children in the Three Gorges Reservoir Region.

Analysis of di-n-butyl phthalate and other organic pollutants in Chongqing women undergoing parturition

In this study, 40 healthy women from Chongqing undergoing parturition were recruited and samples of venous blood, umbilical cord blood, breast milk and urine were collected for analysis of organic pollutants by GC/MS. A total of 292 different organic pollutants were detected, including 156 in venous blood, 139 in umbilical cord blood, 176 in breast milk and 138 in urine. Nine different PAEs were detectable in the samples: di-n-butyl phthalate (DBP), bis(2-methylpropyl) phthalate, butyl-8-methyl-nonyl phthalate, di-ethyl phthalate, butyl-2-methylpropyl phthalate, butyloctyl phthalate, di-dodecyl phthalate, di-isodecyl phthalate, and di-tridecyl phthalate. DBP was one of the chemicals detected at the highest frequency (48.82%). DBP concentrations were 84.75+/-33.52, 52.23+/-32.50, 57.78+/-35.42 and 24.93+/-18.67 microg/l in venous blood, umbilical cord blood, breast milk and urine, respectively. This study represents the first investigation of organic pollutants in a Chongqing population.

Phthalate Levels in Cord Blood Are Associated with Preterm Delivery and Fetal Growth Parameters in Chinese Women

Data concerning the effects of phthalate exposure on preterm delivery and fetal growth are limited in humans. In this paper, we assessed the relationship between 15 phthalate levels in cord blood and preterm delivery and fetal growth parameters in 207 Chinese women going into labor. Exposure to phthalates except DCHP was associated with gestational age reduction and preterm delivery (p<0.05). There were associations between phthalates and fetal growth parameters, many of which disappeared when analyses were adjusted for gestational age, especially in male infants (Only DEEP was associated with birth weight; DEP, DNHP, BBP, DNP with abdominal circumference; DEP, DBP, DCHP, DEHP with femur length in female infants. And DPP, DBEP was associated with birth length in male infants. p<0.05). This study indicates that prenatal exposure to phthalates is associated with younger gestational age and preterm delivery. Also, phthalate exposure may adversely affect fetal growth parameters via gestational age reduction and preterm delivery with a significant gender effect.

Ovotoxicity and PPAR-mediated aromatase downregulation in female Sprague-Dawley rats following combined oral exposure to benzo[a]pyrene and di-(2-ethylhexyl) phthalate

The aim of the present study was to determine the ovotoxicity of female Sprague-Dawley (SD) rats exposed to benzo[a]pyrene (B[a]P) and di-(2-ethylhexyl) phthalate (DEHP), either alone or in combination; the molecular mechanism and the combined effects were also evaluated. Female rats were given intragastric administration of control (corn oil), B[a]P (5 and 10mg/kg), DEHP (300 and 600 mg/kg) and B[a]P+DEHP (at 5mg/kg and 300 mg/kg respectively, or at 10mg/kg and 600 mg/kg respectively) on alternate days for 60 days. Relative ovary weight, estrous cycle, 17β-estradiol blood level, ovarian follicle populations, granulosa cell apoptosis, and gene and protein expression of P450Arom and PPAR were investigated. Our study demonstrated that the combination of B[a]P and DEHP exerts ovotoxicity in female rats and suppression of sex hormone secretion and homeostasis, which is associated with prolonged estrous cycles, decreases in ovarian follicle populations and granulosa cell apoptosis involving a PPAR-mediated signaling pathway of action of the two chemicals. In addition, based on qualitative assessment of the combined toxicity, no interaction effects were observed following combined B[a]P and DEHP administration.

Protective effects of green tea polyphenols against subacute hepatotoxicity induced by microcystin-LR in mice

Green tea polyphenols (GTP) have been shown to possess anti-oxidative, anti-mutagenic and anti-carcinogenic activities. The present study aimed to evaluate the chemopreventive efficacy of GTP against subacute hepatotoxicity induced by microcystin-LR (MC-LR) in mice and also elucidates the underlying mechanisms. In this study, healthy Kunming male mice (24-26gbw) were randomly assigned to five groups. Group I was fed on normal diet and water ad libitum as control. Group II was maintained on normal diet and received MC-LR intraperitoneal injection (10μg/kg/day) from day 6 till sacrifice. Mice in groups III, IV and V were daily pre-treated with GTP through intragastric administration at doses of 50, 100 and 200mg/kg/day from day 0 prior to MC-LR intoxication, consecutively 18 days. The results showed MC-LR alone led to oxidative stress and to damage antioxidant defense system, as evidenced by elevation of serum and liver lipid peroxidation. Additionally, hepatocellular apoptosis and injury were significantly observed. GTP pre-treatment caused a significant elevation in serum antioxidant enzymes GSH and SOD activities as well as a decrease in hepatic lipid peroxidation MDA level and serum ALT, AST, ALP activities. GTP pre-treatment obviously inhibited hepatocellular apoptosis and up-regulated Bcl-2 protein expression. The damages in liver were less severe in GTP pre-treated mice in correlation with the biochemical parameters. In summary, this study confirmed that repeated exposure to MC-LR could induce hepatotoxicity. Our study demonstrated that GTP can reduce MC-LR-induced oxidant stress and prevent biochemical parameters and pathological changes caused by MC-LR in a dose-dependent manner. The results indicated that tea polyphenols have a potential to be developed as a preventive agent against MC-LR-induced toxicity and the mechanism involved in the protection could be due to their antioxidant activities.

Arsenite exposure altered the expression of NMDA receptor and postsynaptic signaling proteins in rat hippocampus.

Chronic arsenic exposure has an adverse effect on neurobehavioral function. Our previous study demonstrated an elevated arsenic level, ultra-structure changes and reduced NR2A gene expression in hippocampus, and impaired spatial learning in arsenite-exposed rats. The NMDA receptor and the postsynaptic signaling proteins CaMKII, postsynaptic density protein 95 (PSD-95), synaptic Ras GTPase-activating protein (SynGAP) and nuclear activated extracellular-signal regulated kinase (ERK1/2) play important roles in synaptic plasticity, learning and memory. We hypothesized that the above molecular expression changes may contribute to arsenic neurotoxicity. In present study, the expression of NMDA receptor and postsynaptic signaling proteins in hippocampus were evaluated in rats exposed to 0, 2.72, 13.6 and 68 mg/L sodium arsenite for 3 months. Decreased protein expression of NR2A, PSD-95 and p-CaMKII α in the hippocampus of arsenite-exposed rats was observed, while the expression of SynGAP, a negative regulator of Ras-MAPK activity, was increased when compared with the controls. Additionally, decreased p-ERK1/2 activity was found in the hippocampus of arsenite-exposed rats. These data suggest that altered expression of NMDA receptor complex and postsynaptic signaling proteins may explain arsenic-induced neurotoxicity.

Occurrence and potential health risk of Cryptosporidium and Giardia in the Three Gorges Reservoir, China.

The Three Gorges Reservoir (TGR) is the biggest lake in the world and a major water source in China. There is no information about occurrence and impact of Cryptosporidium and Giardia on the aquatic ecosystem. 61 surface water samples from 23 monitoring sites and 5 treated effluent samples were collected and analyzed. Cryptosporidium oocysts and Giardia cysts were found, respectively, in 86.4% and 65.2% of a total of 66 water samples, with high concentrations in treated effluent. The mean percent recovery was 29.14% for oocysts and 34.86% for cysts. A seasonal pattern was observed, with positive samples for Cryptosporidium more frequent in flood period and positive samples for Giardia more frequent in impounding period. Counts of enterococci, fecal coliforms and total coliforms, and turbidity were significantly associated with Cryptosporidium concentration in backwater (water in a main river which is backed up by the Three Gorges Dam) areas of tributaries but not Giardia. High associations were also found between oocyst and cyst in backwater areas of tributaries and cities. The risks of infection and illness due to water consumption in four different exposure routes were estimated. The results showed that swimming in the TGR has the highest infection risk with 1.39 × 10(-3) per time (95% confidence interval (CI): 0.05-600.3 × 10(-5)) for Cryptosporidium and 2.08 × 10(-4) per time (95% CI: 0.05-878.87 × 10(-6)) for Giardia, while directly drinking unboiled tap water treated with the conventional process has the highest morbidity with 524.98 per 100,000 population per year (95% CI: 10.35-2040.26) for Cryptosporidium and 5.89 per 100,000 population per year (95% CI: 0.08-22.67) for Giardia. This study provides new useful information for drinking water plants, health care workers and managers to improve the safety of tap water and deduce the risk of surface water contamination in China.

Determination of Environmental Exposure to Microcystin and Aflatoxin as a Risk for Renal Function Based on 5493 Rural People in Southwest China.

Although the nephrotoxicity of microcystin and aflatoxin has been observed in animal and clinical cases, few population data are available. We conducted a cross-sectional study in Southwest China to investigate the association of renal function indicators (RFIs, including BUN, SCr, and eGFR) with exposure to microcystin and aflatoxin in 5493 members of the general population. Microcystin-LR levels in water and aquatic products and aflatoxin B1 levels in daily foods were measured by ELISA, and individual estimated daily intake (EDI) was assessed on the basis of the measurement and questionnaire. We found that participants with abnormal RFIs had a much higher mean level of microcystin-LR EDI than those with normal RFIs and that there was a significant increasing trend for abnormal rates and odds ratios of RFIs with increasing microcystin-LR EDI quartiles (p for trend = 0.000). Compared with the lowest quartile of microcystin-LR exposure, those in the highest quartile had significantly higher risks of abnormal BUN (OR = 1.80, 95% CI = 1.34-2.42), SCr (OR = 4.58, 95% CI = 2.92-7.21), and eGFR (OR = 4.41, 95% CI = 2.55-7.63), respectively, but no higher risk was found in subjects with higher AFB1 exposure. After adjustment for confounding factors, risk associations with microcystin-LR persisted. Consequently, our results suggest that microcystin, rather than aflatoxin, might be one important risk of renal-function impairment.