Emerging organic contaminants in the river Ganga and key tributaries in the middle Gangetic Plain, India:Characterization, distribution & controls

The presence and distribution of emerging organic contaminants (EOCs) in freshwater environments is a key issue in India and globally, particularly due to ecotoxicological and potential antimicrobial resistance concerns. Here we have investigated the composition and spatial distribution of EOCs in surface water along a ∼500 km segment of the iconic River Ganges (Ganga) and key tributaries in the middle Gangetic Plain of Northern India. Using a broad screening approach, in 11 surface water samples, we identified 51 EOCs, comprising of pharmaceuticals, agrochemicals, lifestyle and industrial chemicals. Whilst the majority of EOCs detected were a mixture of pharmaceuticals and agrochemicals, lifestyle chemicals (and particularly sucralose) occurred at the highest concentrations. Ten of the EOCs detected are priority compounds (e.g. sulfamethoxazole, diuron, atrazine, chlorpyrifos, perfluorooctane sulfonate (PFOS), perfluorobutane sulfonate, thiamethoxam, imidacloprid, clothianidin and diclofenac). In almost 50% of water samples, sulfamethoxazole concentrations exceeded predicted no-effect concentrations (PNECs) for ecological toxicity. A significant downstream reduction in EOCs was observed along the River Ganga between Varanasi (Uttar Pradesh) and Begusarai (Bihar), likely reflecting dilution effects associated with three major tributaries, all with considerably lower EOC concentrations than the main Ganga channel. Sorption and/or redox controls were observed for some compounds (e.g. clopidol), as well as a relatively high degree of mixing of EOCs within the river. We discuss the environmental relevance of the persistence of several parent compounds (notably atrazine, carbamazepine, metribuzin and fipronil) and associated transformation products. Associations between EOCs and other hydrochemical parameters including excitation emission matrix (EEM) fluorescence indicated positive, significant, and compound-specific correlations between EOCs and tryptophan-, fulvic- and humic-like fluorescence. This study expands the baseline characterization of EOCs in Indian surface water and contributes to an improved understanding of the potential sources and controls on EOC distribution in the River Ganga and other large river systems

RP-Ring: A Heterogeneous Multi-FPGA Accelerator

To reduce the cost of designing new specialized FPGA boards as direct-summation MOND (Modified Newtonian Dynamics) simulator, we propose a new heterogeneous architecture with existing FPGA boards, which is called RP-ring (reconfigurable processor ring). This design can be expanded conveniently with any available FPGA board and only requires quite low communication bandwidth between FPGA boards. The communication protocol is simple and can be implemented with limited hardware/software resources. In order to avoid overall performance loss caused by the slowest board, we build a mathematical model to decompose workload among FPGAs. The dividing of workload is based on the logic resource, memory access bandwidth, and communication bandwidth of each FPGA chip. Our accelerator can achieve two orders of magnitude speedup compared with CPU implementation

Occurrence of antibiotic resistance genes and potentially pathogenic bacteria in the Yangtze River tributary (Nanjing section) and their correlation with environmental factors

Freshwater environments are vulnerable to emerging contaminants such as Antibiotic resistance genes (ARGs), and their occurrence is gaining more attention. However, the occurrence of ARGs along with potential pathogens is less explored. The current study aimed to evaluate the abundance of ARGs and explore bacterial communities for the presence of potential bacterial pathogens in water samples collected from a tributary to the Yangtze River in Nanjing. Twelve physico-chemical parameters were analyzed, followed by quantifying 10 ARGs targeting sulfonamide ( sul1, sul2 ), tetracycline ( tetG, tetM, tetQ ), erythromycin ( ermB ), vancomycin ( vanA, vanR ), and streptomycin ( strA, strB ) using real-time PCR and bacterial diversity characterization using high-throughput 16 S rRNA sequencing. The results indicated poor water quality and high-level eutrophication in most sampling locations. sul1 , sul2 , and strB were dominant in the study area with average concentrations of 6.8, 7.1, and 6.5 Log _10 gene copies/100 ml, respectively. Proteobacteria, Cyanobacteria, Bacteroidetes, and Actinobacteria were the main phyla detected in the study area, and genus-level analysis revealed the presence of eight potential pathogenic and ten fecal-associated bacterial genera at several locations in the study area. The distance-based Redundancy analysis indicated that total phosphorus, electrical conductivity, dissolved oxygen, total dissolved solids, ammonium-N (NH _4 ^+ -N), and chlorophyll a had significantly influenced the bacterial community composition in the monitored locations. Correlation analysis demonstrated that water temperature, pH, NH _4 ^+ -N, and total organic carbon were positively correlated with sul2 , tetG , and vanR genes, indicating that these environmental parameters significantly affected the ARGs distribution pattern. Overall, our results provide valuable information regarding the occurrence of ARGs and potential bacterial pathogens in the study area; however, their co-existence highlights increased human health risks