Level of Contamination of Fishponds Water in Pesticide Residues and Metallic Trace Elements (Pb, Cd, As, Hg): Case of Fishponds of ZEPREGUHE (Daloa, Côte d’Ivoire)

Fishponds waters intended to satisfy the nutritional needs of the populations in terms of supply of fish resources are strongly and unfortunately exposed to the mobility and dispersion of metallic trace elements (TMEs) or to the persistence in the environment and in the form of pesticide residues from human activities. The objective of this work is to evaluate, on the one hand, the levels of identified pesticide residues and, on the other hand, those of researched TMEs (lead, cadmium, mercury and arsenic) in the waters of ponds used for fish farming in Zépréguhé, a locality located 9 km from the town of Daloa in the centre-west of Côte d’Ivoire. The dosage of the samples carried out by means of a gas chromatograph coupled to a mass spectrometer (GC/MS) made it possible to detect nine (9) pesticide molecules, including eight (8) organochlorines and a single molecule from the pyrethroid family, obtained from the detection limit of 0.006 μg/L and the quantification limit of 0.018 μg/L. The maximum average concentration was obtained with α-endosulfan for a content reaching 0.8038 μg/L and well above the maximum admissible concentration of 0.1 μg/L. The TMEs were quantified using an atomic absorption spectrophotometer (AAS). Arsenic is the most abundant metal with an average concentration of 9.497 μg/L. With the exception of lead, these measured levels are above the acceptable limit values for freshwater. This study showed that human activities such as the use of fertilisers and plant protection products in plantations, sand extraction and road traffic have a negative impact on the quality of the water in ponds used for fish breeding.

The Economic Importance and Social Values of Traditional Aquaculture in Rural Sierra Leone

The economic viability and social value of traditional aquaculture in rural Sierra Leone were evaluated. The hypothesis tested was that traditional methods of farming fish in ponds were not economically viable, so farmers were investing their time/labour in less risky and more profitable livelihoods activities. The assumption in this assessment was that fish farming is an economic activity, and that for farmers to adopt or choose it over other livelihoods, the benefit-cost ratio of fish farming must be higher than that of alternative livelihoods. The main objective of the study was to assess why local farmers failed to adopt modem market oriented aquaculture production systems introduced by the Ministry of Fisheries and Marine Resources in rural Sierra Leone. Two hundred farmers owning fishponds on family lands were interviewed using semi-structured questionnaires and farmers＇ responses were analyzed using statistical tools （SPSS 16.0）. The mean contributions of different livelihoods to total annual incomes of farmers and the social values they attached to these livelihoods were compared. Results of the study suggested that traditional fish fanning was economically viable across the range of pond sizes sampled; but the medium-sized ponds were more profitable than the smallest and largest ponds, and labour accounted for 70% of total annual production costs in the systems assessed. The average benefit-cost ratio of 2.3 for fish fanning was favorable compared with that of 0.83 for rice farming, which was ranked as most popular livelihood activity by farmers. The payback period for traditional aquaculture investments was less than five years using informal investment loans （without interest）, and was favorably compared with that for tree crops fanning, which was also popular among farmers. Additional benefits of fish fanning included social capital and maintenance of kinship relationships.

The Importance of Hunting and Hunting Areas for Big and Small Game （Food） for the Tourism Development in the Crna River Basin in the Republic of Macedonia

The Crna River is a river in the Republic of Macedonia, right tributary to Vardar. Its source is in the mountains of Western Macedonia, west of Krusevo. It flows through the village of Sopotnica, and southwards through the plains east of Bitola. The name means ＂black river＂ in Macedonian, which is translation for its former Thracian name. The purpose of this paper is to show the hunting and hunting areas for big and small Game （food）, the structure of the areas of certain hunting, fishing, fishing water objects, fish species, fishponds up to 20 years shown by municipalities and individual farms with ponds in the basin of Black River. It had used statistical data for the hunting grounds by areas, fishing ponds. Fish is very diverse in this river. Hunting in the Black River basin is of great importance for the economy of Republic of Macedonia. It is also a necessary factor for development of other economic activities.

Phytosynthetic bacteria (PSB) as a water quality improvement mechanism in saline-alkali wetland ponds

The efficiency of phytosynthetic bacteria (PSB) to improve the water quality in saline alkali ponds was studied, the result showed that (1) PSB application could increase the content of DO, NO\+-\-3\|N and effective phosphorus (EP) in ponds; (2) the changes of COD were not evident, just effective in later period after PSB application; (3) PSB application could decrease the contents of NH\+-\-4\|N (NH\-3\|N), NO\+-\-2\|N ; (4) PSB application could improve the structure of the effective nitrogen (EN) and EP, stimulate the growth of phytoplankton, and increase primary productivity, and finally increase the commercial profits of ponds because of the increase of EP and the decrease of EN contents; (5) the effect exerting speed of PSB was slower, but the effect sustaining time was longer; (6) the appropriate concentration of PSB application in saline alkali wetland ponds was 10×10 -6 mg/L, one time effective period was more than 15 days. So PSB was an efficient water quality improver in saline alkali ponds.

Shallow groundwater nitrogen responses to different land use managements in the riparian zone of Yuqiao Reservoir in North China

This field study investigated the nitrogen concentrations in the shallow groundwater from an ephemeral stream and four land uses： cropland, two-year restored （2yr） and five-years restored （Syr） woodlands, fishponds, and the nitrogen flux in the riparian zone of Yuqiao Reservoir. The groundwater nitrate-N concentrations in cropland were the highest among the four land uses. Total dissolved nitrogen （TDN） and nitrate-N concentrations in the 2yr woodland were significantly （p 〈 0.05） higher than in 5yr woodland. The lowest nitrogen concentrations were detected in fishponds. Nitrate-N was the main form in cropland and 2yr woodland, whereas both nitrate-N and dissolved organic nitrogen （DON） were the main species in 5yr woodland and fishponds. But, ammonium-N was the main form in the ephemeral stream. During the rainy season, the groundwater flow with dissolved nitrogen drains from upland into the reservoir along the hydraulic gradient. The woodland between the cropland and reservoir could act as a buffer to retain shallow groundwater nitrogen. The dominant form of ammonium-N in the groundwater TDN pool in ephemeral stream indicated that nitrogen from the village and orchard in upland flowed into the reservoir via subsurface flow. The fishpond was not an important pollution source for nitrogen transfer via shallow groundwater.

Human Influences on the Development of Acid Sulphate Soils in the Pearl River （the Zhujiang） Delta

In the Pearl River Delta with more than 1000 years of intensive land reclamation history, the developmentof acid sulphate soils has been generally limited in terms of their acid potential (pyrite content) and spatialextent. This is attributed to the rapid delta progradation, partially resulted from increasing sediment yieldcaused by deforestation within the catchment and the empolderment in the estuarine embayment. Theempolderment practice accompanied by the clearance of mangroves stopped the upward growth of the pyriticlayer on the one hand and limited the vertical accretion of non-pyritic freshwater sediments over the pyriticestuarine sedimellts on the other. In such a case, the Pyritic layer in the area is frequently thin and ofshallow occurrence. Under forced leaching-recharge conditions for the paddy rice cultivation, the leaching ofacid sulphate materials prevails over its production and this leads to a net loss in pyrite oxidation products.Land excaVation for fishpond farming accelerates Pyrite oxidation due to the direct exposure of the pyriticsediments to air on the pond bunds. Severe acidification can intensify the environmental degradation ofestuarine ecosystems.