We simultaneously measured bacterial production (BP), bacterial respiration (BR), alkaline phosphatase activity (phos) and ectoaminopeptidase activity (prot) in relation to biogeochemical parameters, nutritive resources and in situ temperature over a 1-year survey at the long-term observatory the SOLEMIO station (Marseille bay, NW Mediterranean Sea). Despite its proximity to the coast, oligotrophic conditions prevailed at this station (yearly mean of Chl a = 0.43 μg dm⁻³, NO₃ = 0.55 μmol dm⁻³ and PO₄ = 0.04 μmol dm⁻³). Episodic meteorological events (dominant winds, inputs from the Rhone River) induced rapid oscillations (within 15 days) in temperature and sometimes salinity that resulted in rapid changes in phytoplankton succession and a high variability in C/P ratios within the particulate and dissolved organic matter. Throughout the year, BP ranged from 0.01 to 0.82 μg C dm−³ h−¹ and bacterial growth efficiency varied from 1 to 39 %, with higher values in summer. Enrichment experiments showed that BP was limited most of the year by phosphorus availability (except in winter). A significant positive correlation was found between in situ temperature, BP, BR and phos. Finally, we found that temperature and phosphate availability were the main factors driving heterotrophic bacterial activity and thus play a fundamental role in carbon fluxes within the marine ecosystem.

Rural nonpoint source (NPS) pollution caused by agricultural wastes has become increasingly serious in the Three Gorges Reservoir Area (TGRA), significantly affecting the reservoir water quality. The grim situation of rural NPS pollution in the TGRA indicated that agrochemicals (chemical fertilizer and pesticide) were currently the highest contributor of rural NPS pollution (50.38 %). The harmless disposal rates of livestock excrement, crop straws, rural domestic refuse, and sewage also cause severe water pollution. More importantly, the backward agricultural economy and the poor environmental awareness of farmers in the hinterland of the TGRA contribute to high levels of rural NPS pollution. Over the past decade, researchers and the local people have carried out various successful studies and practices to realize the effective control of rural NPS pollution by efficiently utilizing agricultural wastes in the TGRA, including agricultural waste biogas-oriented utilization, crop straw gasification, decentralized land treatment of livestock excrement technology, and crop straw modification. These technologies have greatly increased the renewable resource utilization of agricultural wastes and improved water quality and ecological environment in the TGRA.

The paper presents a compilation of various autotrophic and heterotrophic ways of solid-phase denitrification. It covers a complete understanding of various pathways followed during denitrification process. The paper gives a brief review on various governing factors on which the process depends. It focuses mainly on the solid-phase denitrification process, its applicability, efficiency, and disadvantages associated. It presents a critical review on various methodologies associated with denitrification process reported in past years. A comparative study has also been carried out to have a better understanding of advantages and disadvantages of a particular method. We summarize the various organic and inorganic substances and various techniques that have been used for enhancing denitrification process and suggest possible gaps in the research areas whi'ch are worthy of future research.

Forty surface sediment samples from the Hunhe River in Northeast China were evaluated for contamination by polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD). The results showed that decabromodiphenyl ether (BDE-209) was the predominant congener, accounting for >98 % of PBDEs in all sediment. The concentrations of BDE-209 and HBCD ranged from 3.96 to 327 ng/g dry weight and 0.05 to 25.8 ng/g dry weight, respectively, suggesting that BDE-209 was more widely applied in the study area. The mean concentrations of BDE-209 and HBCD in the downstream portion of the Hunhe River (BDE-209 148 ng/g dry weight and HBCD 3.74 ng/g dry weight) were found to be relatively higher than those in the upstream portion of the Hunhe River and the Dahuofang Reservoir, revealing an association with municipal sewage and industrial effluent received from the cities of Fushun and Shenyang. γ-HBCD was the most abundant diastereoisomer of all three analyzed HBCD isomers; however, marked elevations of α-HBCD were also found in most sediment samples. Surprisingly, the relative abundance (mean 38 %) of α-HBCD in sediment from the upstream portion of the Hunhe River was significantly higher (p < 0.006, t test) than those in Dahuofang Reservoir (mean 24 %). Moreover, the severe heavy metal contamination associated with the frequent mining activities in this region was tentatively suggested as being responsible for the increased levels of α-HBCD.

This work compared the toxicity of ZnO nanoparticles (ZnO-NPs), ZnO bulk, and ZnCl₂ on microbial activity (C and N transformations and dehydrogenase and phosphatase activities) and their uptake and toxic effects (emergence, root elongation, and shoot growth) on three plant species namely wheat, radish, and vetch in a natural soil at 1000 mg Zn kg⁻¹. Additionally, plants were also tested at 250 mg Zn kg⁻¹. The effects of the chemical species on Zn extractability in soil were studied by performing single and sequential extractions. ZnCl₂-1000 presented the highest toxicity for both taxonomic groups. For microorganisms, ZnO-NPs demonstrated adverse effects on all measured parameters, except on N transformations. The effects of both ZnO forms were similar. For plants, ZnO-NPs affected the growth of more plant species than ZnO bulk, although the effects were small in all cases. Regarding accumulation, the total Zn amounts were higher in plants exposed to ZnO-NP than those exposed to ZnO bulk, except for vetch shoots. The soil sequential extraction revealed that the Zn concentration in the most labile forms (water soluble (WS) and exchangeable (EX)) was similar in soil treated with ZnO (NP and bulk) and lower than that of ZnCl₂-treated soil, indicating the higher availability of the ionic forms. The strong correlations obtained between WS-Zn fraction and the Zn concentrations in the roots, shoots, and the effects on shoot weight show the suitability of this soil extraction method for predicting bioavailable Zn soil for the three plant species when it was added as ZnO-NPs, ZnO bulk, or ZnCl₂. In this work, the hazard associated with the ZnO-NPs was similar to ZnO bulk in most cases.

We identified antibiotic-resistant bacterial isolates from the surface waters of Jiulong River basin in southern China and determined their extent of resistance, as well as the prevalence and characterization of three classes of integrons. A phylogenetic analysis of 16S ribosomal DNA (rDNA) sequences showed that 20 genera were sampled from a total of 191 strains and the most common genus was Acinetobacter. Antimicrobial susceptibility testing revealed that the 191 isolates were all multiresistant and there were high levels of resistance to 19 antimicrobials that were tested, particularly the β-lactam, sulfonamide, amphenicol, macrolide, and rifamycin classes. Moreover, class 1 integrons were ubiquitous while only five out of 191 strains harbored class 2 integrons and no class 3 integrons were detected. The variable region of the class 1 integrons contained 30 different gene cassette arrays. Nine novel arrays were found in 65 strains, and seven strains had empty integrons. Among these 30 arrays, there were 34 different gene cassettes that included 25 resistance genes, six genes with unknown functions, two mutant transposase genes, and a new gene. The unique array dfrA1-sat2-aadA1 was detected in all five isolates carrying the class 2 integron. We found that antibiotic-resistant bacterial isolates from Jiulong River were diverse and antibiotic resistance genes associated with integrons were widespread.

Vibrios and other enteric pathogens can be found in wastewater effluents of a healthy population. We assessed the prevalence of three non-cholerae vibrios in wastewater effluents of 14 wastewater treatment plants (WWTP) in Chris Hani and Amathole district municipalities in the Eastern Cape Province of South Africa for a period of 12 months. With the exception of WWTP10 where presumptive vibrios were not detected in summer and spring, presumptive vibrios were detected in all seasons in other WWTP effluents. When a sample of 1,000 presumptive Vibrio isolates taken from across all sampling sites were subjected to molecular confirmation for Vibrio, 668 were confirmed to belong to the genus Vibrio, giving a prevalence rate of 66.8 %. Further, molecular characterisation of 300 confirmed Vibrio isolates revealed that 11.6 % (35) were Vibrio parahaemolyticus, 28.6 % (86) were Vibrio fluvialis and 28 % (84) were Vibrio vulnificus while 31.8 % (95) belonged to other Vibrio spp. not assayed for in this study. Antibiogram profiling of the three Vibrio species showed that V. parahaemolyticus was ≥50 % susceptible to 8 of the test antibiotics and ≥50 % resistant to only 5 of the 13 test antibiotics, while V. vulnificus showed a susceptibility profile of ≥50 % to 7 of the test antibiotics and a resistance profile of ≥50 % to 6 of the 13 test antibiotics. V. fluvialis showed ≥50 % resistance to 8 of the 13 antibiotics used while showing ≥50 % susceptibility to only 4 antibiotics used. All three Vibrio species were susceptible to gentamycin, cefuroxime, meropenem and imipenem. Multiple antibiotic resistance patterns were also evident especially against such antibiotics as tetracyclin, polymixin B, penicillin G, sulfamethazole and erythromycin against which all Vibrio species were resistant. These results indicate a significant threat to public health, more so in the Eastern Cape Province of South Africa which is characterised by widespread poverty, with more than a third of the population directly relying on surface water sources for drinking and daily use.

The natural (S₀) and chemically modified Phanerochaete chrysosporium including the methylation of amino groups (S₁), acetylation of hydroxyl groups (S₂), lipid removal (S₃), esterification of carboxyl groups (S₄), and base hydrolysis (S₅) were characterized, and their sorption for phenanthrene (PHE) was investigated. The sorption isotherm of PHE on natural biomasses was apparently linear, while it was nonlinear for the modified ones. The partition coefficient (K d) describing the sorption affinity of PHE by biomasses followed the order of S₀ (9.24 L g⁻¹) > S₅ (8.94 L g⁻¹) > S₁ (7.13 L g⁻¹) > S₂ (6.97 L g⁻¹) > S₃ (6.38 L g⁻¹) > S₄ (3.51 L g⁻¹) and decreased as temperature increased. The PHE adsorption fitted well to the pseudo-second-order kinetic model, and the sorption capacity was in the order of S₅ (2041.5 μg g⁻¹) > S₀ (1768.8 μg g⁻¹) > S₂ (1570.9 μg g⁻¹) > S₁ (1552.9 μg g⁻¹) > S₃ (1346.4 μg g⁻¹) > S₄ (991.0 μg g⁻¹). Moreover, the π–π and electron donor–acceptor interactions may govern PHE sorption which processed spontaneously and exothermally. The natural and modified biomasses, especially the base hydrolysis treated ones, were economical and effective biosorbents for PHE removal.

Many epidemiological studies from all over the world have reported that populations of rural and urban environments differ in their health issues due to the differences in the countrywide pollution pattern. In developing countries, various occupational cohorts and subsections of the population in urban and rural areas are routinely exposed to several environmentally widespread contaminants. Polycyclic aromatic hydrocarbons (PAHs) are a group of over hundred different compounds and have ubiquitous presence in rural and urban environments. Smoke from the combustion of biomass fuel contains a high concentration of carcinogenic PAHs, which are related with several human morbidities. The sources and types of biomass fuel are diverse and wide in distribution. Limited numbers of literature reports have focused the significant impact of PAHs on several components of blood, both in human and wildlife. The toxicity of PAHs to rapidly dividing cells (e.g., bone marrow cells) and other tissues is largely attributed to their reactive oxygenated metabolites, potential of causing oxidative stress, and the adducts of their metabolites with DNA. This review aims to encompass the blood-related effects of PAHs and associated human health risks—an aspect that needs further research—on the population of developing countries of the world in particular.

The main source of natural estrogens to municipal wastewater is human excretions via urine or feces, thus their concentrations in raw wastewater should show positive linear relationship with their human excretions. This study mainly focused on their concentration relationship in raw wastewater. Based on comparison between chemical analyses and predictions through human excretion rates, the observed concentrations of estriol (E₃) in municipal wastewater were found to be noticeably lower than the predicted values. The main cause for the disparity is that substantial conjugated E₃also exists in raw wastewater. This work suggested that monitoring both E₃and its conjugates is necessary to get more accurate E₃removal performance of wastewater treatment plants (WWTPs).