[Temporal and Spatial Variation Characteristics and Source Analysis of Agricultural Non-point Source Pollution Load in Guangdong During the Past 20 Years].

The agricultural non-point source pollution (ANPSP) load in Guangdong province is very large and has a serious impact on the regional ecological environment. Inventory analysis was used to assess and analyze the temporal and spatial variation characteristics of the ANPSP load of Guangdong province during 1999-2019, and the sources of ANPSP were discussed, as well as the relationship between them. The results showed that, during the past 20 years, the total ANPSP pollution loads of Guangdong province decreased by 6.08%, and the pollution loads of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) increased by -11.88%, 4.99%, and 26.17%, respectively. The input intensity of chemical fertilizers and pesticides increased by 112.19% and 60.38%, respectively. The Pearl River Delta had the highest ANPSP loads in Guangdong province, followed by those in northern, western, and eastern Guangdong. Livestock and poultry breeding were the main sources of COD, the total percent fertilizers and livestock and poultry breeding were the main sources of TN, and livestock and poultry breeding and aquaculture were the main sources of TP. In addition, the contribution of pollutants discharged from aquaculture showed an obvious increasing trend. There were certain differences in the pollution sources in different regions. In western Guangdong, northern Guangdong, and eastern Guangdong, livestock and poultry breeding were the main sources of COD and TP, and fertilizer was the main source of TN; by contrast in the Pearl River Delta, aquaculture had become the main source of TN and TP pollution loads. The correlation results showed that the decline in the total ANPSP in Guangdong province was mainly due to the increase in high urbanization rate and the decrease in the proportion of rural population. In general, there were stage changes in the time and differences in spatial characteristics and sources of ANPSP in Guangdong province. A combination of comprehensive treatment and targeted pollution treatment should be adopted, and fertilizer reduction measures and pollution treatment in the aquaculture should be strengthened in an all-around way, focusing on strengthening the treatment of pollution from aquaculture in the Pearl River Delta region and the treatment of rural life pollution in northern Guangdong.

Occurrence, fate and ecological risk of chlorinated paraffins in Asia: A review.

Chlorinated paraffins (CPs), complex mixtures of polychlorinated alkanes, are widely used in various industries and are thus ubiquitous in the receiving environment. The present study comprehensively reviewed the occurrence, fate and ecological risk of CPs in various environmental matrices in Asia. Releases from the production and consumption of CPs or CP-containing materials, wastewater discharge and irrigation, sewage sludge application, long-range atmospheric transport and aerial deposition have been found to be most likely sources and transport mechanisms for the dispersion of CPs in various environmental matrices, such as air, water, sediment, soil and biota. CPs can be bioaccumulated in biota and biomagnified through food webs, likely causing toxic ecological effects in organisms and posing health risks to humans. Inhalation, dust ingestion and dietary intake are strongly suggested as the major routes of human exposure. Research gaps are discussed to highlight the perspectives of future research to improve future efforts regarding the analysis of CPs, the environmental occurrence and elimination of CPs, the total environmental pressure, and the risks to organisms and populations.

Organophosphorus flame retardants and plasticizers: sources, occurrence, toxicity and human exposure.

Due to the restricted use and ban of brominated flame retardants, organophosphorus compounds (OPs), extensively used as flame retardants and plasticizers, are ubiquitous in various environmental compartments worldwide. The present study shows that the release of OPs from a wide variety of commercial products and wastewater discharge might be considered as primary emission sources and that high potential of long-range atmospheric transport and persistence of OPs would be responsible for their presence in various matrices on a global scale. The occurrence and environmental behaviors of OPs in diverse matrices (e.g., dust, air, water, sediment, soil and biota) are reviewed. Human exposures to OPs via dermal contact, dust ingestion, inhalation and dietary intake are comprehensively evaluated. Finally, this study identifies gaps in the existing issues and generates a future agenda for the emerging contaminants OPs.