جستجوی مقالات مرتبط با کلیدواژه « Aquaculture » در نشریات گروه « آب و خاک »

The present research was conducted in order to investigate the role of silver nanoparticles (Ag-NPs) in water disinfection in aquaculture systems and also the environmental effects caused by its release in the environment. The literature review showed that very few studies have been recorded about the antiviral effects of silver nanoparticles in aquaculture systems. Meanwhile, silver nanoparticles showed positive effects against many bacterial pathogens such as Aeromonas and Vibrio as well as fungal agents such as Aspergillus and Candida. Since the mentioned microbial strains are among the most important and common pathogenic agents in Iran's breeding systems, the use of silver nanoparticles with the appropriate amount (provided that more than not allowed) can be useful. Examination of various scientific sources showed that the safe and permissible level of silver nanoparticles has been studied in many farmed fish species, including rainbow trout, silver carp, common carp and zebra fish. Considering this issue, breeders can use these substances to control and prevent the spread of infectious diseases in breeding systems, considering the safe and permissible level of silver nanoparticles for each aquatic species. Based on the comparisons, the antimicrobial effects of silver nanoparticles are very high among metal nanoparticles. In general, the release of these substances into aquatic ecosystems can affect the health of many aquatic animals, including fish, and even have negative effects on human health due to the transfer of silver nanoparticles in the food chain.

Water scarcity is a serious problem for agricultural production in arid and semi-arid. Furthermore, development of new water resources in these areas is too expensive. Now, treated wastewater (TWW) is commonly used as an alternative source for irrigating to alleviate freshwater use. One of the most nutrient-rich wastewaters for plants is aquaculture effluent which contains appropriate nutrients such as nitrogen and phosphorus. The aquaculture effluent which is often drained to rivers causes both an environmental challenge and an agricultural opportunity. The integration of aquaculture with agricultural systems has been identified as a way to increase food production, protect the environment and enhance food security. On the other hand, emitter clogging is the main problem with use of wastewaters in drip irrigation systems which reduces the emitter discharge, emission uniformity, irrigation efficiency and increases maintenance costs. Time and location of partial clogging of emitters, under wastewater using conditions, is an important issue. Thus, in the present study, the mentioned problem was investigated particularly about aquaculture effluents.
For this purpose, three separate drip irrigation systems were established. Netafim and Micro-flopper emitters were used in each treatment, with both 4 and 8 l/h discharges. During a season, 42 irrigation events were done using fresh water (as a control), and aquaculture effluent (with and without ending drainage of pipes). Emitter discharges was measured for each emitter type by volumetric method, through all irrigation events for the all study treatments. Then, clogging percentages were calculated. To perform statistical analysis of data, all the laterals were divided into three hypothetical of elementary, middle and ending one-third parts. Each of these parts included four loops of lateral pipe. The emitter location (on the lateral pipe) factor, along with others (time, type of water, emitter type and emitter discharge) considered in the analysis. Emitter's clogging percentage data were analyzed in the form of combined analysis, based on randomized complete block design with the mentioned factors. MSTAT-C and SAS software was used for statistical analyses.
The results of present study showed that the clogging of Micro flopper 4 l/h emitters has increased sharply over the time in both effluent treatments (with and without ending drainage of pipes), and it has even passed the critical point at the fourth time interval in this study. Therefore, use of these emitters is unsuitable for irrigation with aquaculture effluent. Also, , clogging in Micro flopper 8 l/h emitters has increased passing time in all treatments, and it has even passed the critical point at the fourth time interval; But, in the third and fourth time periods, the role of ending drainage of pipes was obvious and positive. Therefore, using these emitters for irrigation with aquaculture effluent will be more appropriate compared with Micro flopper 4 l/h emitters, if the proper management is applied, such as ending drainage or full washing of lateral pipes. Clogging percentages of Netafim 4 l/h emitters have not any significant differences between three treatments in all of the time intervals. It means that these emitters had the least dependent on water quality and irrigation management compared to the other experienced emitters in this study. Also, the clogging percentages for these emitters never reached the critical levels during the irrigation season, both in the case of fresh water and wastewater usage. Therefore, use of these emitters is very suitable for irrigation with aquaculture effluent. The results showed that for all studied emitters, using aquaculture effluent caused emitter clogging mostly in the ending one-third of lateral pipes. This problem was more acute in the emitters with 8 liters per hour discharges. Therefore, using these emitters with application of aquaculture effluent, ending drainage of lateral pipes or full washing of them is more necessary.
The results of present study showed that the effect of elapsing time on the emitter clogging was in acceptable range in Netafim emitters but not in Micro flopper emitters, when aquaculture effluent was used in drip irrigation. And in both effluent treatments (with and without ending drainage of pipes), Netafim emitter's performance was significantly (P

According to the reports, industrial livestock activities have most pernicious and harmful impacts on water resources quality. Livestock activities include cattle breeding, animals feeding, cleaning animals resting sites, the storage of livestock manure and even abandoned places for livestock keeping impose large negative effects on water quality. Such impacts stems from high density or livestock producing large amounts of waste. The livestock population density is not the only factor affecting the quality of water resources, but also to manage the collection and disposal of animal waste can also affect the quality of water resources. As per surveys and field reconnaissance carried out on Mashhad, in the current situation, animal waste disposal in most cases is done in unwise and unsystematic manner (accumulation and disposal in agricultural land). In general in Mashhad plain, the main cause of water pollution in the vicinity of livestock production is incorrect storage of animal manure so that annually many manure are produced. In case they enter to aquifer, it will causes most hazardous pollution. In ingoing study, the vulnerability of Mashhad Plain Aquifer to pollutants is evaluated and given importance of groundwater resources in the provision of drinking water, some solutions to prevent, control and reduce pollution will be discussed.