Trace analysis of 28 antibiotics in plant tissues (root, stem, leaf and seed) by optimized QuEChERS pretreatment with UHPLC-MS/MS detection.

Phytoremediation has proven to be an effective in-situ treatment technique for antibiotic contamination. Due to the immature methods of extracting multi-antibiotics in different plant tissues, the antibiotic absorption and transportation mechanism in the phytoremediation process has yet to be resolved. Therefore, an improved Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) pretreatment with ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) detection method for 28 antibiotics in different plant tissues (root, stem, leaf and seed) was developed in this study. The optimized method showed satisfactory performance with recoveries for most antibiotics ranging from 70% to 130% (except sulfadoxine with 138 ± 8.84% in root, sulfameter with 68.9 ± 1.87% and sulfadoxine with 141 ± 10.0% in seed). The limits of detection (LODs) of the target compounds in root, stem, leaf and seed were 0.04 ± 0.02 ~ 2.50 ± 1.14 ng/g, 0.05 ± 0.02 ~ 1.78 ± 0.42 ng/g, 0.06 ± 0.01 ~ 2.50 ± 0.14 ng/g and 0.13 ± 0.10 ~ 3.64 ± 0.74 ng/g, respectively. This developed method was successfully applied to the determination of antibiotics in different tissues of hydroponic wetland plants exposed to antibiotics-spiked water for one-month. Sixteen of 28 spiked antibiotics were detected in plant tissue samples. Overall, of these 16 antibiotics, all were detected in root samples (from < LOQ to 1478 ± 353 ng/g), eleven in stem samples (from < LOQ to 425 ± 47.0 ng/g), and nine in leaf samples (from < LOQ to 429 ± 84.5 ng/g). This developed analytical method provided a robust tool for the simultaneous screening and determination of antibiotics in different plant tissues.

Altered development and reproduction in western mosquitofish (Gambusia affinis) found in the Hanxi River, southern China.

The current study investigated the development and reproductive health of western mosquitofish (Gambusia affinis) in the Hanxi River, which has been heavily contaminated by municipal wastewaters from towns in Dongguan of southern China. Western mosquitofish collected from four study sites, Songmu (SM), Yangwu (YW), Hengli (HL), and Zhangcun (ZC) of the Hanxi River, as well as a reference site (LX) of the Liuxi River, were dissected and analyzed for development parameters (total length, wet body mass, liver mass, gonad index, and population composition), reproductive parameters (oocyte count and weight of females, and sperm count and viability of males), and morphology (anal fin in males and females, and hemal spines in males). With the exception of the origin site (SM), mosquitofish from the Hanxi River exhibited significantly decreasing development and reproduction levels. Significant correlations were found for the collected mosquitofish between the morphological and reproductive indexes (ratio of perpendicular distance to tip to vertical distance from the tip on the 16th hemal spine) versus the sperm count of males; ratio 16P:16D versus sperm viability of males; segments of anal fin ray 3 versus oocyte count of females; and segments of anal fin ray 3 versus average oocyte mass of females. The results demonstrated that both male and female mosquitofish in the Hanxi River were affected by the discharged wastewaters, as reflected in their morphological changes in comparison with those of mosquitofish from the reference site.

2-Hydr-oxy-3-methoxy-benzoic acid monohydrate.

The asymmetric unit of the title compound, C(8)H(8)O(4)·H(2)O, contains two organic mol-ecules which are connected by the two water mol-ecules through O-H⋯O hydrogen bonds, forming an R(4) (4)(12) ring. Further O-H⋯O hydrogen bonds assemble these rings through R(6) (6)(18) rings, giving rise to infinite helical chains arranged around the b axis. These helical chains are assembled by offset π-π stacking inter-actions [centroid-centroid distance = 3.6432 (8) Å] between the aromatic rings of neigboring chains, forming a supra-molecular network.

Poly[hexa-aqua-tri-µ-malonato-didysprosium(III)].

The title compound, [Dy(2)(C(3)H(2)O(4))(3)(H(2)O)(6)](n), forms a coordination polymeric structure comprising hydrated dysprosium ions and malonate ligands. In the asymmetric unit, there are one dysprosium ion, one and a half malonate ligands, and three water mol-ecules. Each Dy(III) atom is coordinated by six O atoms from four malonate ligands and by three water mol-ecules, and displays a tricapped trigonal-prismatic coordination geometry. The malonate ligands adopt two types of coordination mode, linking dysprosium centres to form a three-dimensional coordination polymer. The extensive network of hydrogen bonds in this polymer enhances the structural stability.

Poly[diaqua-µ(2)-isonicotinato-µ(2)-oxalato-terbium(III)].

In the crystal structure of the title complex, [Tb(C(6)H(4)NO(2))(C(2)O(4))(H(2)O)(2)](n), the Tb(III) ion is coordinated by two O atoms from two isonicotinate (inic) anions, four O atoms of two oxalate anions, and two water mol-ecules, displaying a distorted square-antiprismatic geometry. The Tb(III) ion, the inic anion and the water mol-ecules occupy general positions. One of the two crystallographically independent oxalate anions is located on a center of inversion, whereas the second is located on the twofold rotation axis. The carboxyl-ate groups of the inic and oxalate anions link the terbium metal centres into layers. These layers are connected by O-H⋯O and N-H⋯O hydrogen bonding into a three-dimensional network.

Organochlorines in sediments and mussels collected from coastal sites along the Pearl River Delta, South China.

The level and pattern of residues of organochlorine pesticide and polychlorinated biphenyls(PCBs) were analyzed in sediment and mussel (Perna viridis) samples from ten coastal sites along the Pearl River Delta, South China. The range of total HCH was < 0.01 to 0.29 ng/g freeze-dried weight in sediment, and < 0.01 to 1.35 ng/g lipid weight in mussels. Average total DDTs concentrations ranged from < 0.01 to 1.04 ng/g in sediment, and < 0.01 to 148.5 ng/g in mussels. Average total PCB concentrations ranged from 16.4 to 198.6 ng/g in sediment, and from 41 to 729.2 ng/g in mussels. Organochlorine pesticide and PCBs in mussels and sediments presented similar distribution patterns. The regression analysis indicated that PCBs concentrations in mussels were significantly correlated (p < 0.01) with concentrations in sediments. However, their concentrations in mussels were several times higher than the concentration detected in surrounding sediments. The major fraction of DDT related compounds measured in mussels and sediments was DDD. Based on average PCB concentrations, penta-, hexa-, and tetrachlorobiphenyls were preferentially accumulated by mussels as compared to the average sediment composition. According to the present results,three organochlorine polluted "hot spot" sites, including Victoria Harbour, Lingding Yang and Huangmao Sea, were found in the Pearl River estuarine zone. HCHs, DDTs and PCBs in all mussel samples were below the limits of 2, 0.2 and 5.0 microg/g wet weight recommended by the Technical Group of Guangdong Coastal Zone Resource Comprehensive Survey and U. S. Food and Drug Administration.

Heavy metals in oysters, mussels and clams collected from coastal sites along the Pearl River Delta, South China.

Concentrations of 8 heavy metals: cadmium (Cd), copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), chromium (Cr), antimony (Sb) and tin (Sn) were examined in 3 species of bivalves ( Perna viridis, Crassostrea rivularis and Ruditapes philippinarum) collected from 25 sites along the Pearl River Delta coastal waters in the South China Sea from July to August 1996. In general, Cd, Cu, Zn and Sn concentrations in the three bivalve species collected from the Estuarine Zone were significantly higher than those collected from the Western and Eastern Zones of the Pearl River Delta, which are related to the existence of various anthropogenic activities in the catchment of the Pearl River Delta. The Western Estuarine Zone is mainly impacted hy Cr, Ni and Cu contamination. In Victoria Harbor, heavy metal contamination is mainly due to Cu and Pb, Cd, Cu and Zn concentrations in oysters were significantly higher than those in mussels and clams. This could be explained by the fact that oysters live mainly in the Estuarine Zone of the Pearl River Delta which receives most of the polluting discharges from the catchment of the Delta. During turbid condition, heavy metals( soluble or adsorbed on suspended particulates) discharged from the Delta are filtered from the water column and subsequently accumulated into the soft body tissues of oysters. Heavy metal concentrations in the three bivalve species were compared with the maximum permissible levels of heavy metals in seafood regulated by the Public Health and Municipal Services Ordinance, Laws of Hong Kong, and it was revealed that Cd and Cr concentrations in the three bivalve species exceeded the upper limits. At certain hotspots in the Delta, the maximum acceptable daily load for Cd was also exceeded.