Lead Isotope Signatures and Source Identification of Heavy Metals in Vegetable Soils Irrigated with Swine Wastewater of Jiangxi Province, China.

The rapid development of livestock and poultry industry in China has caused serious environment pollution problems. To understand the heavy metals accumulation and identify their sources, 7 heavy metals contents and lead isotope ratios were determined in 24 soil samples from vegetable fields irrigated with swine wastewater in Dongxiang County, Jiangxi Province, China. The results showed that the concentration of Cr, Ni, Cu, Zn, As, Cd and Pb in the swine wastewater irrigated vegetable soils varied from 38.5 to 86.4, 7.57 to 30.6, 20.0 to 57.1, 37.5 to 174, 9.18 to 53.1, 0.043 to 0.274 and 12.8 to 37.1 mg/kg, respectively. The soils were moderately to heavily polluted by As, moderately polluted by Cr, Ni, Cu, Zn and Cd, and unpolluted to moderately polluted by Pb. Sampling soils were classified as moderately polluted according to the Nemerow comprehensive pollution index. Lead isotope and Principal Component Analysis (PCA) analysis indicated that swine wastewater irrigation and atmospheric deposition were the primary sources of the heavy metals.

Orofacial myofunctional changes in skeletal Class III patients after bimaxillary orthognathic surgery.

The aim of this study is to investigate the effect of bimaxillary orthognathic surgery on orofacial myofunctional changes in skeletal class III patients. 35 patients who received Le Fort I maxillary advancement osteotomy and mandibular SSRO setback were included in this study. Facial expression function was analyzed by "placid" or "smile" expressions using chL-chR, ∠chRnchL, and ls-li. Occlusal force and balance were analyzed using a T-scan III digital occlusal analysis system. Maximum mouth opening (MMO) was measured prior to surgery and 2/14/28/42/90/180/360 days after surgery. After surgery, patients recovered facial expressions in no less than 3 months for both the "placid" or "smile" facial expression. Patients obtained significantly improved 'smile' expressions 3 months after the operation compared to preoperative "smiles", and this improvement remained stable 12 months after the operation. Occlusal force was significantly decreased with the balance of occlusion lost immediately after surgery. These conditions gradually recovered, and patients finally obtained a more balanced and stronger occlusion [occlusion balance: 6.7 ± 2.7 mm vs. 4.1 ± 3.0 mm (day -7 vs. day 42); occlusion force: 19.6 ± 7.0 kg vs. 24.2 ± 9.3 kg (day -7 vs. day 180)]. However, patients had smaller postoperative mouth opening compared to preoperation opening during our follow-up. Our results confirmed that orthognathic surgery obstructs orofacial myofunctions of skeletal class III patients in the short-term. In the long-term, orthognathic surgery results in more stable and balanced orofacial myofunctions. By understanding the process of functional recovery of orofacial muscles after orthognathic surgery, we hope to accelerate patient's recovery from surgery.

Tracing the organic matter source of cage culture sediments based on stable carbon and nitrogen isotopes in Poyang Lake, China.

Collected sediment samples from the cage fish farm were measured to determine carbon and nitrogen stable isotope compositions and to understand the influence of the aquaculture waste on the sediment. The average δ13C of the sediment organic matter was -27.2 ‰ and -26.5 ‰, and the average δ15N value was 5.6 ‰ and 6.2 ‰ in October 2017 and November 2018, respectively. A linear mixing model was used to calculate the contribution ratios of the aquaculture waste in sediment organic matter. The contribution ratio of fish feces was 53.9 % and 25.5 %, and the contribution ratio of waste feed was 18.4 % and 52.6 % in October 2017 and November 2018, respectively. The sediment in the "cage fish area" was characterized by high waste feed ratio in sediment organic matter. The sediment organic matter was affected by the aquaculture waste even at sites 1500 m away from the cage fish farm.

Carbon and Nitrogen Stable Isotopes Evidence for the Environmental Impact of the Cage Fish Farm in Poyang Lake, China.

The carbon and nitrogen stable isotope compositions of the sediment organic matter, fish feed and fish feces were measured to assess the impact of the aquaculture waste from the cage fish farm in Poyang Lake. The results provide evidence of the non-negligible effect of aquaculture waste on the sediment organic matter. The δ13C and δ15N of sediments varied from - 27.62 to - 25.66‰ and 4.83 to 6.92‰, respectively. The sediment organic matter had a mixed source of waste feed, fish feces and plankton. The average contribution ratio of waste feed and fish feces was 53.1% and 24.6%, respectively. The aquaculture derived organic matter ratio was high with ranging from 57.6 to 95.6%. The aquaculture waste seemed to disperse widely enough to influence the study site about 2.5 km distance from the cage. The dispersion and resuspension were the main two factors which can explain the great effect area found in this study.

Metals Pollution and Ecological Risk Assessment of Sediments in the Poyang Lake, China.

The concentrations of several metals and their geochemical species in surface sediment from Poyang Lake main channel and its tributary entrance were analyzed. Results showed that the concentrations of Cu (28.1-213 mg/kg), Zn (82.6-257 mg/kg), Pb (49.8-81.4 mg/kg) and Ni (33.5-56.0 mg/kg) were higher than the background values, while Cd (0.15-0.81 mg/kg) was lower. Zn, Cu and Ni were predominately bound to residual fraction. The content of Pb in the Fe-Mn oxides fractions was considerable. And Cd had highest concentration of exchangeable and carbonate fractions. The geoaccumulation index showed that the sediments were unpolluted with Cd, moderately polluted with Pb, Zn and Ni, while moderately to heavily polluted by Cu. Principal component analysis indicated that Ni was mainly lithogenic in origin and Cu, Pb, Zn and Cd were influenced by anthropogenic contamination. The concentrations of Cu, Pb and Zn were above the threshold effects level (TEL) but below the probable effects level (PEL), Cd was below TEL, whereas the contents of Ni were above PEL. The potential ecological risk index showed Cu posed moderate ecological risks, Cd, Ni, Pb and Zn posed low ecological risk. The general ecological risk belonged to the high risk.

Heavy Metal Contamination and Ecological Risk Assessment of Swine Manure Irrigated Vegetable Soils in Jiangxi Province, China.

Heavy metal are often added to animal fodder and accumulate in the soils with swine manure. In this study, heavy metal (Cu, Pb, Cd, Zn, As and Cr) concentrations were determined in agricultural soils irrigated with swine manure in Jiangxi Province, China. Results showed that the average concentrations of Cu, Zn, As and Cr (32.8, 93.7, 21.3 and 75.8 mg/kg, respectively) were higher than the background values, while Pb and Cd (15.2 and 0.090 mg/kg, respectively) were lower than the background values. Contamination factors [Formula: see text] indicated that they were generally moderate for Cu, Zn, As and Cr and generally low for Pb and Cd. The contamination degree (C d ) was calculated to be 7.5-10.0 indicating a moderate degree of contamination. The geoaccumulation index (Igeo) indicated that the soils were unpolluted with Zn, Cd and Pb, while unpolluted to moderately pollute with Cr, Cu and As. The single ecological risk factor [Formula: see text] revealed that the six heavy metals all belonged to low ecological risk. The ecological risk indices suggested that all the sampling sites were at low risk level.

Study of heavy metal speciation in branch sediments of Poyang Lake.

This study concentrates on the environmental pollution level of sediments in the six branches of Poyang Lake, the biggest fresh water lake in China. This is the first systematic report on the speciation analysis of heavy metals (Cu, Co, Cd, Pb, and Ni) in the six branches of the lake. A reported analytical procedure involving a five-step sequential extraction is used for the partition of particulating heavy metals. The sediment samples are analyzed using flame atomic absorption spectroscopy (FAAS). Experimental results obtained from five replicate samples of fluvial bottom surface sediments at the sampling points demonstrated that the relative standard deviation of the sequential extraction procedure was generally better than 10% (Cd except). The average extracted contents of the five elements, analyzed after all five steps, are found to be (mg/kg) for Cu: 26.89, Co: 16.25, Cd: 1.08, Pb: 37.98, and Ni: 20.46. The content of the exchangeable species was generally lower. Except Cu, the percentage of the species bond to organic matter was lower than 20%. The fractions containing the most metal for Cu, Co, and Ni were the residues (52.26%, 45.28%, and 74.82%, respectively).