Estimation and prediction of plastic waste annual input into the sea from China

Marine plastic debris has been a pervasive issue since the last century, and research on its sources and fates plays a vital role in the establishment of mitigation measures. However, data on the quantity of plastic waste that enters the sea on a certain timescale remain largely unavailable in China. Here, we established a model using material flow analysis method based on life cycle assessment to follow plastic product from primary plastic to plastic waste with statistical data and monitoring data from accurate sources. This model can be used to estimate and forecast the annual input of plastic waste into the sea from China until 2020. In 2011, 0.547 3-0.751 5 million tons of plastic waste entered the seas in China, with a growth rate of 4.55% per year until 2017. And the amount will decrease to 0.257 1 to 0.353 1 million tons in 2020 under the influence of governmental management. The amount of plastic waste discharged from coastal areas calculated in this study was much larger than that from river, thus it is suggested to strengthen the governance and control of plastic waste in coastal fishery activities in China in order to reduce the amount of marine plastic waste input.

Occurrence, variations, and risk assessment of neonicotinoid insecticides in Harbin section of the Songhua River, northeast China

Neonicotinoid insecticides(NNIs)have been intensively used and exploited,resulting in their presence and accumulation in multiple environmental media.We herein investigated the current levels of eight major NNIs in the Harbin section of the Songhua River in northeast China,providing the first systematic report on NNIs in this region.At least four NNIs in water and three in sediment were detected,with total concentrations ranging from 30.8 to 135 ng L^(-1) and from 0.61 to 14.7 ng g^(-1) dw,respectively.Larger spatial variations in surface water NNIs concentrations were observed in tributary than mainstream(p<0.05)due to the intensive human activities(e.g.,horticulture,urban landscaping,and household pet flea control)and the discharge of wastewater from many treatment plants.There was a significant positive correlation(p<0.05)between the concentrations of residual imidacloprid(IMI),clothianidin(CLO),and S4NNIs in the sediment and total organic carbon(TOC).Due to its high solubility and low octanol-water partition coefficient(Kow),the sediment-water exchange behavior shows that NNIs in sediments can re-enter into the water body.Human exposure risk was assessed using the relative potency factor(RPF),which showed that infants have the highest exposure risk(estimated daily intake(SIMIeq EDI):31.9 ng kg^(-1) bw$d^(-1)).The concentration thresholds of NNIs for aquatic organisms in the Harbin section of the Songhua River were determined using the species sensitivity distribution(SSD)approach,resulting in a value of 355 ng L^(-1) for acute hazardous concentration for 5%of species(HC5)and 165 ng L^(-1) for chronic HC5.Aquatic organisms at low trophic levels were more vulnerable to potential harm from NNIs.

Integrated biomarkers in wild crucian carp for early warning of water quality in Hun River, North China

Metabolizing enzymes play important roles in the detoxification of various pollutants in aquatic organisms, thereby they can also be used to provide early-warning signals of environmental risks. Real-time quantitative reverse-transcription polymerase chain reaction assays were developed to quantify cytochrome P450 1A （CYP1A）, superoxide dismutase （SOD）, glutathione peroxidase （GPx）, catalase （CAT）, and glutathione-S-transferase （GST） in crucian carp （Carassius auratus）. The methods were then used to detect the respective mRNA expression levels in liver tissue in wild crucian carp from the Hun River, North China. CYP1A mRNA expression was significantly up-regulated in fish from stations $5, $6, and $8 （p 〈 0.05）. SOD mRNA expression was significantly down-regulated in downstream areas relative to fish from upstream sites （p 〈 0.05）; GPx and CAT mRNA expression levels were also down-regulated at $9 （p 〈 0.05）. In contrast, GST mRNA expression showed no obvious change between fish collected from up- or downstream areas of the river. Finally, an integrated biomarker response was used to evaluate the integrated impact of pollutants in the Hun River and allow better comprehension of the real toxicological risk of these investigated sites.