Search

Heavy metals (HMs) have the characteristics of high toxicity, long residual time, and difficult degradation, which pose a potential threat to aquatic ecosystems. The distribution and migration of HMs in different media can reflect their potential impact on aquatic ecosystem health. In this study, we analyzed the distribution characteristics of seven HMs (Zn, Cu, Cr, Ni, Hg, As, and Pb) in the water and sediment and five groups of organisms (fish, Crustacean, cephalopod, bivalvia, and gastropoda) in the sea ranching area of Haizhou Bay and explored the regularity of HM accumulation from water and sediments to organisms. The results showed that in the water, Zn and Hg had the smallest concentrations in the nearshore area, Cr had the lowest concentrations in the offshore area, and As, Cu, Pb, and Ni had the lowest concentrations in the central area. In the sediment, Hg had the smallest concentrations in the nearshore area and As, Pb, Cr, Cu, Ni, and Zn had the lowest concentrations in the offshore area; the average contents of seven heavy metals all meet the Class I standard of sediments in China. The concentrations of Cu and Zn in crustaceans were significantly higher than those in fishes (p < 0.05), and As showed a higher enrichment effect in cephalopods. Under the influence of feeding habits and habitat environment, the BAF value of benthic crustaceans and bivalvia accumulated HMs from sediments is high, and the BAF value of fish accumulated HMs from water and sediments is low. Overall, the concentration of HMs in water is high, and HMs in sediments are in good condition, crustaceans and bivalviaa have a strong ability to accumulate HMs from water and sediments, while fish are weak. Therefore, in order to ensure the safety of biological quality, it is necessary to focus on the discharge of heavy metal pollutants near the coast in the future. [ABSTRACT FROM AUTHOR]

This research investigated the combined use of sewage sludge (SS) and plant growth-promoting rhizobia (PGPR) for Ridge gourd (Luffa acutangula (L.) Roxb.) cultivated under field conditions. The different treatments of SS and PGPR such as 0% (soil as control), 5% SS, 5% SS + PGPR, 10% SS, and 10% SS + PGPR were applied to assess their impacts on seedling growth, biochemical response, and yield performance of Ridge gourd. The results showed that the highest seedling emergence (92.3 ± 2.1%), fresh biomass (9.6 ± 0.3 g), growth rate (1.4 ± 0.1 g/day), seedling length (15.5 ± 0.3 cm), root length (10.4 ± 0.3 cm), total chlorophyll (3.2 ± 0.1 mg/g), crop yield (13.8 ± 0.1 kg/plant), and average crop yield per harvest (2.8 ± 0.1 kg/plant) were observed in 10% SS + PGPR treatment. The enzyme activities of superoxide dismutase (SOD; µg/g) and catalase (CAT: µg/g) were significantly lowered after PGPR inoculation in higher SS treatments. The results of principal component (PC) and Euclidian clustered distance analyses showed a positive influence of SS dose on soil nutrient availability and Ridge gourd's growth, biochemical responses, and yield performance. Moreover, the elemental analysis showed that the bioaccumulation factor (BAF < 0.90) and health risk index (HRI < 0.40) of selected metal elements (Cd, Cr, Cu, Fe, Mn, and Zn) were within the permissible limits, indicating consumption of Ridge gourd fruits was safe. The outcomes of this study suggest the potential use of SS and PGPR for improved Ridge gourd production and contribution towards sustainable development goal (SDG) 12 on responsible consumption and production of vegetable crops. [ABSTRACT FROM AUTHOR]