A 2-yr (1997–1998) survey aiming at the establishment of national data bases concerning the quality of surface waters has been conducted in the major river systems of Macedonia, N. Greece. This paper presents the physicochemical parameters(pH, conductivity, total suspended solids, temperature and DO),the organic pollution parameters (BOD₅, COD) and the major N and P species (NO₃ ⁻, NO₂ ⁻,NH₄ ⁺,organic N, orthophosphates and total P) determined at 25 sampling sites located on main rivers, tributaries, streams andditches that drain the major rural, agricultural, urban and industrial areas of N. Greece. Use of multivariate statistics is also made to identify the principal factors which influencethe chemistry of the water in individual river systems.The eutrophication status of the examined systems was evaluatedby means of N/P ratios. Mean N/P ratios showed large variationsamong sampling sites ranging from potential N- to P-limitationconditions. N/P ratios at particular sampling sites showed also great temporal variability thus suggesting temporary states of N- or P- limitation. Most frequently, highest ratio values wereobserved during winter and early spring. Comparisons are made between data from this study region and literature on rivers elsewhere.

Phosphorus and nitrogen can leach from porous golf greens potentially causing degradation of ground water quality. Agreenhouse experiment was carried out with 52 cm columns (15 cm diam.) made to USGA green specifications and sodded to `Tifdwarf' bermudagrass to determine the effects of fertilizer sources at various rates on P and N leaching. Fertilizers were balanced soluble and controlled-release (polyand sulfur coated) sources at N rates of 0, 12, 24, and 49 kg N ha⁻¹ and at P rates of 0, 5, 11, and 21 kg ha⁻¹ every other week for a total of 6 applications. Controlled-release N was from NH₄ and urea and the soluble source N was from KNO₃, urea, and (NH₄)PO₄. Irrigation rate was 0.63 cm per day initially and increased to 1.25 cm per day at week 7. Weeklyleachate collections for 23 weeks were analyzed for P andNO₃-N. Concentrations of N and P were lower in the leachatefor the controlled-release source than for the soluble source. Leaching of P continued for the entire 23 weeks of theexperiment, whereas N was essentially exhausted by week 15indicating that P leaches at a slower rate than N. For the low Prate (5 kg ha⁻¹) for the controlled-release source there was no increase in P concentration in the leachate compared to control. Thus, low P rates will not result in degradation of water quality due to increased P. For the controlled-release source at the low rate <10% of the P added leached, whereasthe values for N were in the range of 20 to 45% for all ratesand sources. Control treatments resulted in N concentrations in the leachate as high as 26 mg L⁻¹. Results show thatP leaching is a potential problem only at high rates of solublesources and high irrigation, whereas N is more readily leached.

Although confined animal production generates enormous per-unit-area quantities of waste, wastewater from dairy and swine operations has been successfully treated in constructed wetlands. However, solids removal prior to wetland treatment is essential for long-term functionality. Plants are an integral part of wetlands; cattails and bulrushes are commonly used in constructed wetlands for nutrient uptake, surface area, and oxygen transport to sediment. Improved oxidation and nitrification may also be obtained by the use of the open water of marsh-pond-marsh designed wetlands. Wetlands normally have sufficient denitrifying population to produce enzymes, carbon to provide microbial energy, and anaerobic conditions to promote denitrification. However, the anaerobic conditions of wetland sediments limit the rate of nitrification. Thus, denitrification of animal wastewaters in wetlands is generally nitrate-limited. Wetlands are also helpful in reducing pathogen microorganisms. On the other hand, phosphorus removal is somewhat limited by the anaerobic conditions of wetlands. Therefore, when very high mass removals of nitrogen and phosphorus are required, pre- or in-wetland procedures that promote oxidation are needed to increase treatment efficiency. Such procedures offer potential for enhanced constructed wetland treatment of animal wastewater.

Swine waste is commonly treated in the USA by flushing into an anaerobic lagoon and subsequently applying to land. This natural system type of application has been part of agricultural practice for many years. However, it is currently under scrutiny by regulators. An alternate natural system technology to treat swine wastewater may be constructed wetland. For this study we used four wetland cells (11 m width 40 m length) with a marsh-pond-marsh design. The marsh sections were planted to cattail (Typha latifolia, L.) and bulrushes (Scirpus americanus). Two cells were loaded with 16 kg N ha-1 day-1 with a detention of 21 days. They removed 51% of the added N. Two additional cells were loaded with 32 kg ha-1 day-1 with 10.5 days detention. These cells removed only 37% of the added N. However, treatment operations included cold months in which treatment was much less efficient. Removal of N was moderately correlated with the temperature. During the warmer periods removal efficiencies were more consistent with the high removal rates reported for continuous marsh systems - often > than 70%. Phosphorus removal ranged from 30 to 45%. Aquatic macrophytes (plants and floating) assimilated about 320 and 35 kg ha-1, respectively of N and P.