Coordinated dynamics of aquaculture ponds and water eutrophication owing to policy: A case of Jiangsu province, China.

Aquaculture ponds (APs) are rapidly expanding globally and are considered crucial for guaranteeing the supply of food, population growth, and economic development. However, the rapid expansion of aquaculture not only brought benefits but also a series of eco-environmental issues, such as water eutrophication. To achieve sustainable development, it is essential to gain a profound understanding of the spatiotemporal evolution of APs, the drivers behind their dynamics, and their relationship with the aquatic environment. Jiangsu Province (JS) in China, a historically significant aquaculture region, encompasses two prominent river basins: the Huai River Basin (HRB) and the Yangtze River Basin (YRB). In light of the construction of an ecological civilization, JS serves as a demonstration and pioneering area for basin protection and development. Therefore, this study focuses on JS, aiming to elucidate the spatiotemporal dynamics of APs, the corresponding relationship with basin management policies, and the impact on water eutrophication. The results revealed that: (1) in 2022, APs in JS were unevenly distributed, with a total area of 3278.78 km2, of which 79 % was located in the HRB. (2) During 2016-2022, APs exhibited an initial growth trend before 2019, followed by a decrease. (3) Due to policy interventions, AP changes within different basins showed opposite trends, and the corresponding water eutrophic state aligned with AP dynamics. The findings of this study can serve as a typical case to provide scientific evidence for the formulation and implementation of policies to improve the water environment in eutrophic basins.

A Novel Reinforcement Learning Collision Avoidance Algorithm for USVs Based on Maneuvering Characteristics and COLREGs.

Autonomous collision avoidance technology provides an intelligent method for unmanned surface vehicles' (USVs) safe and efficient navigation. In this paper, the USV collision avoidance problem under the constraint of the international regulations for preventing collisions at sea (COLREGs) was studied. Here, a reinforcement learning collision avoidance (RLCA) algorithm is proposed that complies with USV maneuverability. Notably, the reinforcement learning agent does not require any prior knowledge about USV collision avoidance from humans to learn collision avoidance motions well. The double-DQN method was used to reduce the overestimation of the action-value function. A dueling network architecture was adopted to clearly distinguish the difference between a great state and an excellent action. Aiming at the problem of agent exploration, a method based on the characteristics of USV collision avoidance, the category-based exploration method, can improve the exploration ability of the USV. Because a large number of turning behaviors in the early steps may affect the training, a method to discard some of the transitions was designed, which can improve the effectiveness of the algorithm. A finite Markov decision process (MDP) that conforms to the USVs' maneuverability and COLREGs was used for the agent training. The RLCA algorithm was tested in a marine simulation environment in many different USV encounters, which showed a higher average reward. The RLCA algorithm bridged the divide between USV navigation status information and collision avoidance behavior, resulting in successfully planning a safe and economical path to the terminal.

Assessment of endocrine-disrupting effects of emerging polyhalogenated carbazoles (PHCZs): In vitro, in silico, and in vivo evidence.

Polyhalogenated carbazoles (PHCZs) are an emerging class of persistent, bioaccumulative compounds that are structurally and chemically related to dioxins. They have been detected widely in sediment, river, and soil samples, but their environmental risks are largely unknown. Therefore, seven common PHCZs were tested for their endocrine disrupting potential in silico, in vitro, and in vivo. A dual-luciferase reporter gene assay was used to detect receptor-mediated (agonist or antagonistic) activity (concentration range: 10-9-10-5 M) against the estrogen receptor α (ERα), glucocorticoid receptor α (GRα), and mineralocorticoid receptor (MR). The alterations in the steroidogenesis pathway were investigated in H295R cells. Antagonistic effects against GRα were observed with five PHCZs, along with an increase in the cortisol levels of H295R cells. The most common effect observed was that of the agonistic activity of ERα, with the molecular docking analysis further indicating that hydrogen bonding and hydrophobic interactions may stabilize the interaction between PHCZs and the estrogen receptor binding pocket. In addition, a seven-day exposure of young female rats to three PHCZs (27-BCZ, 3-BCZ, and 36-BCZ) resulted in changes in serum E2 levels, uterine epithelium cell heights, and relative uterus weights. In conclusion, endocrine-disrupting effects, especially the estrogenic effects, were observed for the tested PHCZs. Such adverse effects of PHCZs on humans and wildlife warrant further thorough investigation.

The potential endocrine disruption of pesticide transformation products (TPs): The blind spot of pesticide risk assessment.

The ecological and health risk assessment of environmental pesticide residues have attracted ever-growing attention; however, their transformation products (TPs) have seldom been considered. Herein, we examined the endocrine-disrupting effects of 4 widely used pesticides as pyriproxyfen (Pyr), malathion (ML), benalaxyl (BX), and fenoxaprop-ethyl (FE), together with their 21 TPs through in vitro and in silico approaches, and found approximately 50% of the TPs exhibited stronger endocrine-disrupting effects than their corresponding parent compounds. Specifically, Pyr and 9 TPs (five TPs of Pyr, one of ML, one of BX, and two of FE) exhibited estrogen-disrupting effects, which were also confirmed by results of E-screen and pS2 expression assays, and molecular docking showed that certain hydroxylated TPs could well mimic the binding mode of estrogen with ERα. Meanwhile, two TPs of Pyr, ML and its TP demonstrated weak glucocorticoid antagonistic activities partially contributed by hydrogen bonds. We also discovered that in H295R cells, all the endocrine disruptors increased hormone secretion and the related gene expression levels. Conclusively, since an increasing number of pesticide TPs have been being detected in various environmental media, a more comprehensive understanding of the ecological risk of pesticide TPs is imperative for risk assessments more extensively and regulatory policy-making on pesticide restriction in the future.

Estrogens in municipal wastewater and receiving waters in the Beijing-Tianjin-Hebei region, China: Occurrence and risk assessment of mixtures.

The potentially high release of estrogens to surface waters due to high population density and local livestock production in the Beijing-Tianjin-Hebei region may pose adverse effects on reproductive systems of aquatic organisms. This study found that total measured concentrations of estrone (E1), 17ß-estradiol (E2), estriol (E3), 17α-ethinylestradiol (EE2) and diethylstilbestrol (DES) were 468 ± 27 ng/L in treated wastewater and 219 ± 23 ng/L in river waters in this region. E2, E3 and EE2 were the predominant estrogens in river waters. The restriction of DES for human use should have been enforced, however concentrations of DES were relatively high compared to other studies. Haihe and Yongdingxin Rivers delivered approximately 1.8 tonnes of estrogens to the Bohai Bay annually. Concentrations of individual estrogens were significantly higher in river waters in the dry season, however, mass loadings were significantly higher in the wet season. The average E2-equivalent concentrations reached 1.2 ± 0.2 and 0.64 ± 0.08 µg-E2/L following long-term and short-term exposure estimates, respectively, in river waters with an EE2 contribution of over 90 %. This could give rise to high risks to fish. Estrogens in river waters largely derived from human excretion. Field studies on estrogenic effects on fish reproductive systems are required locally considering high estrogen contamination levels.

Maternal ambient air pollution exposure with spatial-temporal variations and preterm birth risk assessment during 2013-2017 in Zhejiang Province, China.

Preterm birth (PTB) can give rise to significant neonatal morbidity and mortality, as well as children's long-term health defects. Many studies have illustrated the associations between ambient air pollution exposure during gestational periods and PTB risks, but most of them only focused on one single air pollutant, such as PM2.5. In this population-based environmental-epidemiology study, we recruited 6275 pregnant mothers in Zhejiang Province, China, and evaluated their gestational exposures to various air pollutants during 2013-2017. Time-to-event logistic regressions were performed to estimate risk associations after adjusting all confounders, and Quasi-AQI model and PCA-GLM analysis were applied to resolve the collinearity issues in multi-pollutant regression models. It was found that gestational exposure to ambient air pollutants was significantly associated with the occurrence of PTB, and SO2 was the largest contributor with a proportion of 29.4%. Three new variables, prime factor (a combination of PM2.5, PM10, SO2, and NO2), carbon factor (CO), and ozone factor (O3), were generated by PCA integration, contributing 63.4%, 17.1%, and 19.5% to PTB risks, respectively. The first and third trimester was the most crucial exposure window, suggesting the pregnant mothers better to avoid severe air pollution exposures during these sensitive periods.

Ecological risk assessment of the increasing use of the neonicotinoid insecticides along the east coast of China.

In the past two decades, neonicotinoid insecticides have been widely used in agricultural activities in China. Many previous studies have investigated the neonicotinoid pollution in aquatic ecosystems, but the status of water safety of neonicotinoid uses in China is very scarce. The present study aims to reveal the spatial and temporal distribution of neonicotinoids in rivers, and then evaluate the ecological risks to aquatic animals. Water samples were collected from all sixteen rivers along the east coast of China during the dry and wet seasons in 2016, and nine individual commercialized neonicotinoids were quantified. Higher concentrations were found during the dry season (343 ±â€¯210 ng/L) compared to those during the wet season (174 ±â€¯162 ng/L). The concentration of neonicotinoid insecticides in river water is mainly affected by the intensity of agricultural activities. The spatial and temporal pollution patterns we discovered suggested the use of neonicotinoids has shifted from old types (i.e., imidacloprid and acetamiprid) to new types (i.e., dinotefuran and nitenpyram) in some areas. The estimated annual quantity of neonicotinoids released into the adjacent seas totaled 1256 ±â€¯780 tons, most of which (95%) ran into the East China Sea due to heavy agricultural use in the Yangtze River Basin. Using the species sensitive distribution (SSD) method, the thresholds for aquatic animals were determined (acute: 362 ng/L; chronic: 58 ng/L). Under current agricultural practices, 27% and 84% of the river water samples exceeded the thresholds for acute and chronic ecological risks, suggesting intervention programs are in urgent need to ensure river water safety for aquatic life in China.