Eutrophication is a major problem in the Baltic Sea, as a result of increased loading of nitrogen and phosphorus. In the coastal parts of Östergötland the soil largely consists of clay and contains high levels of phosphorus bound to clay particles. Erosion of the soil in agricultural areas makes the water turbid and transports phosphorus to the Baltic Sea. The aim of this project was to examine the relationship between phosphorus and turbidity in the coastal streams of Östergötland. The aim was also to evaluate the possibility to use turbidity as a surrogate measure for phosphorus. Water samples from 41 streams along the coast of Östergötland were collected once from each location 7 – 11 of April 2014. Variables examined were turbidity, total phosphorus, molybdate reactive phosphorus and water color (absorbance 420 nm). On average, particulate phosphorus made up 80 % of total phosphorus. The study showed a significant correlation between total phosphorus and turbidity (R2adj=0.879, P<0.01, linear regression). Water color was not correlated with total phosphorus. A multiple regression with turbidity and water color as independent variables resulted in a slightly improved model (R2adj = 0,886), but was regarded as not meaningful considering the additional efforts. The conclusion of the project is that is it possible to use turbidity as a surrogate measure in these streams. / Övergödning av Östersjön är ett stort problem orsakat av ett överskott av kväve och fosfor. I de östra delarna av Östergötland består jordarna till stor del av lera och innehåller rikligt med fosfor bundet till lerpartiklarna. Vid erosion från jordarna grumlas kustmynnande vattendrag och fosfor transporteras ut till Östersjön. Syftet med projektet var att undersöka om mätning av turbiditet kan användas för att uppskatta koncentrationen av totalfosfor i Östergötlands kustmynnande vattendrag. En fältstudie genomfördes där 41 vattendrag provtogs en gång per lokal den 7 - 11 april 2014. Vattenprover från lokalerna analyserades med avseende på totalfosfor, molybdatreaktiv fosfor, turbiditet och färg (absorbans 420 nm). I genomsnitt så bestod 80 % av totalfosfor av partikulärt bunden fosfor. Det fanns ett signifikant samband mellan totalfosfor och turbiditet (R2 adj =0,879, P<0,01, linjär regression) men inte mellan färg och totalfosfor. Vid multipel regression med turbiditet och färg som oberoende variabler förbättras förklaringsgraden så marginellt (R2adj=0,886) att det inte motiverar analys av färg, då det ger en ökad arbetsinsats. Projektet visar att turbiditet går att använda som ersättningsmått för totalfosforhalt i kustmynnande vattendrag i Östergötland.

The environmental sanitation situation in Kampala’s peri-urban areas was reviewed and investigated through field studies, structured interviews with personnel from key institutions and administration of questionnaires to households in a selected peri-urban settlement (Bwaise III Parish).  In this settlement, specific field and laboratory measurements were undertaken so as to create a better understanding of the environmental sanitation situation, anthropogenic pollution loads and their transport and impact (with a focus on Phosphorus) in Kampala’s Peri-urban areas in pursuit of interventions for improving the environmental sanitation and protecting the shallow groundwater resource there. The review revealed that the urban poor in Kampala, like elsewhere in developing countries, are faced with inadequate basic services caused by a combination of institutional, legal and socio-economic issues and that the communities’ coping strategies are in most cases detrimental to their health and well-being. Field surveys showed that excreta disposal systems, solid waste and greywater are major contributors to the widespread shallow groundwater contamination in the area. Field measurements revealed that the water table responds rapidly to short rains (48 h) due to the pervious (10-5-10-3 m/s) and shallow (<1 mbgl) vadose zone, which consists of foreign material (due to reclamation). This anthropogenically influenced vadose zone has a limited contaminant attenuation capacity resulting in water quality deterioration following rains. The only operational spring in the area is fed by regional baseflow meaning a wider protection zone. The spring discharge exhibited microbial quality deterioration after rains primarily as a result of poor maintenance of the protection structure. Subsurface phosphorus (P) transport mechanisms appeared to be a combination of adsorption, precipitation, leaching from the soil media and through macropore flow with the latter two playing an important role in the wet season. The Langmuir isotherm described the phosphorus sorption data well (R2³ 0.95) and the best prediction of Langmuir sorption maximum (Cmax) had organic carbon, Ca and available phosphorus and soil pH as significant predictors. Loosely bound P (NH4Cl-P) was the least fraction (<0.4% of total P) in all layers indicating a high binding capacity of P by the soils implying that the soils have a capacity to adsorb additional P loads. Simulation results from the preliminary numerical model built in this study based on field and laboratory measurements indicate that rainfall infiltration rates > 7x10-3 mm/s drive shallow groundwater contamination with higher intense rains of relatively longer duration (³ 70 mm within 48 h) reducing phosphorus transport. Sensitivity analysis of the model input with respect to how long it takes to pollute the subsurfacehad the phosphorus sorption coefficients as being more influential than the pore size and air entry values. There are however, key contrasts between the model simulations and field observations which are useful in guiding new efforts in data collection. The study reveals that intervention measures to improve the environmental sanitation and protect the shallow groundwater in the peri-urban settlements are of a multidisciplinary nature necessitating action research with community participation. / QC 20100917

Hälsosamma ekosystem försörjer oss med livsviktiga resurser och tjänster – ekosystemtjänster så som skydd mot översvämning. I Norra Östersjöns vattendistrikt, som Mälaren tillhör, är statusen på den ekosystemtjänsten dålig. Detta beror till stor del på en omfattande dikning och brist på svämplan i området. Under perioder med skyfall riskerar därför området runt Mälaren och dess tillrinnande vattendrag att drabbas av översvämningar som skadar matproduktion, infrastruktur och miljö. Övergödning är redan ett problem i området och stora tillskott av fosfor till följd av översvämmade jordbruksmarker kan orsaka stora algblomningar och försämrad livsmiljö för vattenlevande organismer. Under augusti och september 2023 föll ovanligt stora mängder regn över mellersta Sverige vilket ökade vattenföringen i vattendragen runt Mälaren och översvämmade vissa av dem. Högfrekventa turbiditetsmätningar från in-situ sensorer installerade i Sagån, Hågaån och Fyrisån, tre vattendrag i Mälarens avrinningsområde, har använts för att undersöka skyfallens effekter på deras vattenföring och beräknad fosfortransport. Resultaten visade en signifikant korrelation mellan ökad vattenföring och ökad fosfortransport, en signifikant ökning under 2023 jämfört med 2018–2022 och signifikanta skillnader mellan vattendragen. Översvämmade Sagån hade extremt höga toppar i beräknad fosfortransport. Resultaten indikerar att övergödningsproblemen i Mälaren kan förvärras i ett framtida klimat med mer intensiva skyfall om inte åtgärder tas för att stärka avrinningsområdets förmåga att hantera stora mängder nederbörd. / Healthy ecosystems provide us with vital resources and services – ecosystem services such as flood protection. In the North Baltic Sea Water District, to which Lake Mälaren belongs, the status of that ecosystem service is poor, largely as a result of extensive draining in the area leading to a lack of floodplains. During periods of torrential rain, the area around Lake Mälaren and its tributaries is therefore at risk to be affected by floods that cause damage to food production, infrastructure and the environment. Eutrophication is already a problem in the area and large additions of phosphorus as a result of flooded agricultural land can cause large algal blooms and degraded habitat for aquatic organisms. During August and September 2023, unusually large amounts of rain fell over central Sweden, which increased the flow of water in Lake Mälarens tributaries and flooded some of them. High frequency turbidity data from in-situ sensors installed in Sagån, Hågaån and Fyrisån, three tributaries to Lake Mälaren, was used to study the effects of the heavy rains on their waterflow and estimated phosphorus transport. The results showed a significant correlation between increased water flow and increased phosphorus transport, a significant increase in 2023 compared to 2018-2022 and significant differences between the tributaries. Flooded Sagån had extremely high peaks in estimated phosphorus transport. The results indicate that the eutrophication problems in Lake Mälaren may worsen in a future climate with more intense downpours unless measures are taken to strengthen the catchment's ability to handle large amounts of rainfall.