Dechlorane Plus (DP) is a chlorinated flame retardant that is currently in intensive use and has been detected extensively in the environment. In China, the temporal and spatial distribution of DP is characterized by sources of point emissions in the south and diffusion to the north and west, including to remote, high-elevation areas, which are characterized by different climatic conditions and topographies. Thus, relatively high and low concentrations of DP have been observed in areas without significant nearby pollution sources. High DP concentrations have been observed in South China because of the recycling of large amounts of electronic waste and the presence of a DP factory. DP in urban areas is not influenced by atmospheric transportation, whereas DP in rural areas originates from atmospheric transmission from specific sources, such as e-waste recycling areas, which vary seasonally. Furthermore, DP in Chinese forest soils has been observed to preferentially accumulate in the mineral horizon due to leaching by precipitation as well as erosion by weathering in the organic horizon. Although the hazard quotient (HQ) has been estimated to be far from 1 for DP manufacturing operators, the HQ might not reveal deleterious effects on humans. Extremely high DP concentrations have been observed in serum samples from DP manufacturing operators in China. Moreover, different isomer-specific accumulation in terrestrial species, except for aquatic biota, shows that syn-DP is preferentially accumulated. Finally, to achieve better understanding of the mechanisms of DP degradation both in nature and in organisms, further laboratory study is needed.

Sweet potato starch wastewater (SPSW) is an industrial food-processing waste product, which is a significant pollution source due to its high chemical oxygen demand (COD), nitrogen, and phosphorus loads. The influence of hydrolytic acidification (HA) process on C, N, and P as well as other main parameters were evaluated. It is essential to treat these wastewaters with effective methods such as HA, a general pretreatment application. In this study, we investigate the scientific link between the changes of different fractions of C, N, and P with particle size distribution in response to the newly introduced HA process. Results showed that the levels of COD, TN, and TP remained ultimately stable; pH and suspended solids (SSs) decreased obviously. HA process exhibits excellent capability of reducing the larger particulars (with diameter of >5 μm) into smaller ones (with diameter of <0.1 μm). The most significant initial concentration contribution to COD, TN, and TP pollution came from particles and matter with a diameter of >5 μm, at 41.8, 57.3, and 43.5%, respectively. While the most significant contribution to COD, TN, and TP was resulting from micro-molecular size particles (<0.1 μm) after 48 h. The smallest particles (<0.1 μm) were the most dominant contribution to all pollutants measured, with COD, TN, and TP contributions of 63.2, 50.4, and 59.3%, respectively. While the contribution of larger particles (particle size >5 μm) reduced to 10.2, 15.3, and 7.1%, respectively.

To further treat the reclaimed municipal wastewater and rehabilitate the aquatic ecosystem of polluted urban rivers, an 18.5-km field-scale ecological restoration project was constructed along Jialu River, a polluted urban river which receives only reclaimed municipal wastewater from Zhengzhou City without natural upland water dilution. This study investigated the potential efficiency of water quality improvement, as well as genotoxicity and cytotoxicity reduction along the ecological restoration project of this polluted urban river. Results showed that the chemical oxygen demand (COD) and ammonia nitrogen (NH-N) of the reclaimed municipal effluent were reduced by more than 45 and 70%, respectively, meeting the Chinese surface water environmental quality standard level IV, while the total phosphorus and metal concentrations had no significant reduction along the restoration project, and Pb concentrations in all river water samples exceeded permissible limit in drinking water set by WHO (2006) and China (GB5749-2006). The in vitro SOS/umu assay showed 4-nitroquinoline-1-oxide equivalent (4-NQO-EQ) values of reclaimed municipal wastewater of 0.69 ± 0.05 μg/L in April and 0.68 ± 0.06 μg/L in December, respectively, indicating the presence of genotoxic compounds. The results of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and hepatic cell apoptosis in zebrafish after a chorionic long-term (21 days) in vivo exposure also demonstrated that the reclaimed municipal wastewater caused significant DNA oxidative damage and cytotoxicity. After the ecological purification of 18.5-km field-scale restoration project, the genotoxicity assessed by in vitro assay was negligible, while the DNA oxidative damage and cytotoxicity in exposed fish were still significantly elevated. The mechanisms of DNA oxidative damage and cytotoxicity caused by the reclaimed municipal wastewater need further study.