Analysis of the Fertilizing and Bioremediation Potential of Leaf Litter Compost Amendment in Different Soils through Indexing Method

This research study explored the efficacy of leaf litter compost as a sustainable soil amendment with the objective of promoting soil health and mitigating the accumulation of potentially toxic elements. The investigation encompassed the impact of various organic compost amendments, including leaf compost, cow dung manure, kitchen waste compost, municipal organic waste compost, and vermicompost. The study employed Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to evaluate soil nutrient levels and concentrations of Potentially Toxic Elements (PTEs) such as arsenic, chromium, cadmium, mercury, lead, nickel, and lithium. The fertilization and bioremediation potential of these compost amendments are quantified using an indexing method. Results indicated a substantial increase in overall nutrient levels (carbon, nitrogen, phosphorus, potassium, and sulfur) in soils treated with leaf compost and other organic composts. Fertility indices (FI) are notably higher in compost-amended soils (ranging from 2.667 to 3.938) compared to those amended with chemical fertilizers (ranging from 2.250 to 2.813) across all soil samples. Furthermore, the mean concentrations of PTEs were significantly lower in soils treated with leaf compost and other organic compost amendments compared to those treated with chemical fertilizers amendments. The assessment through the indexing method revealed a high clean index (CI) for leaf compost amendment (ranging from 3.407 to 3.58), whereas the chemical fertilizer amendment exhibits a relatively lower CI (ranging from 2.78 to 3.20). Consequently, leaf compost and other organic composts exhibit the potential to enhance sustainable productivity, promoting soil health and environmental safety by improving nutrient levels and remediating potentially toxic elements in the soil.

Potential toxic risk of heavy metals from sediment of the Pearl River in South China

Based on the monitoring of five heavy metal elements in the surface sediments of the Pearl River in South China, potential toxicity of the heavy metals was assessed using consensus-based sediment quality guidelines （SQGs） method and geo-accumulation （Igeo） index method. The monitoring results showed the heavy metal concentrations were significantly and positively correlated with each other, demonstrating a common trend in variation of concentration in the surface sediments. The assessment using the consensus-based SQGs method showed the potential toxicity of Cu was the highest, and Cd was the lowest. The evaluation based on mean probable effect concentration （PEC） quotient showed the region was seriously polluted with high toxicity heavy metals. Correlation analysis revealed a significant and positive correlation between the mean PEC quotient and the average of Igeo with a correlation coefficient of 0.926 （n = 23, P 〈 0.01）. In conclusion, the consensus-based SQGs and mean PEC quotient are applicable to assess potential toxicity risks of heavy metals in freshwater sediments in the Pearl River.

Assessment of toxicity potential of metallic elements in discarded electronics:A case study of mobile phones in China

The electronic waste (e-waste) is increasingly flooding Asia,especially China.E-waste could precipitate a growing volume of toxic input to the local environment if it was not handed properly.This makes the evaluation of environmental impact from electronics an essentially important task for the life cycle assessment (LCA) and the end-of-life management of electronic products.This study presented a quantitative investigation on the environmental performance of typical electronics.Two types of disposed mobile...

Potentially toxic metal concentration,spatial distribution,and health risk assessment in drinking groundwater resources of southeast Iran

In this study, the concentration and spatial distribution of potentially toxic metals(PTMs), including arsenic(As), cadmium(Cd), chromium(Cr), lead(Pb), copper(Cu), iron(Fe), manganese(Mn), and magnesium(Mg) in 23 wells and drinking groundwater distribution networks of Rafsanjan, located in southeast Iran were evaluated. Moreover, the assessment of carcinogenic and non-carcinogenic risks was estimated by Monte Carlo simulation(MCS). The results showed that the concentrations of As and Pb in more than 99% and 23.46% of the study area, respectively, were higher than the maximum concentration level(10 μg/L). The mean concentration of other metals, including Cd, Cr, Cu, Fe, Mg, and Mn in all drinking water resources was within the WHO standard level. The mean hazard quotient(HQ) for As in the age group of children was 9.246 and adults 2.972, indicating high non-carcinogenic risk of As in the study area. The lifetime cancer risk(LTCR) of As was 1.36 E-3 for adults and 1.52 E-2 for children, indicating high non-carcinogenic risk of As. The level of HQ and LTCR for Pb in both age groups was in the acceptable range. The results of sensitivity analysis showed that the most effective variables were pollutant concentration and body weight(BW), respectively. Finally, it can be concluded that exposure to PTMs, especially As through drinking water in the study area can have significant effects on people’s health living in the area;therefore, it is necessary to treat and remove As from groundwater resources before drinking or using for domestic purpose.

Atmospheric deposition fluxes and health risk assessment of potentially toxic elements in Caohai Lake(Guizhou Province,China)

In this study,the sources of potentially toxic elements(PTEs)from atmospheric deposition in the waters of Guizhou’s Caohai Lake were investigated in addition to the potential risks to human health.Moss bags were used to enrich PTEs from atmospheric deposition,and eight monitoring sites that best represented geographic variation were established around Caohai Lake.Moss bags were collected and examined at every 3 months to identify spatiotemporal patterns of dry and wet atmospheric deposition of PTEs.Zn was the most abundant metal identified from deposition in Caohai(72.07%–95.94%),followed by Pb and Cd,while Hg was the least abundant(0.008%–0.354%).The contributions of wet deposition of PTEs were greater than those of dry deposition,and deposition during the heating season from December to April was greater than that between April to July.Hg was mainly derived from atmospheric dry deposition(65.38%–84.44%).Spatial distribution analysis indicated that atmospheric deposition was associated with the intensity of human activities and heating emissions.Exposure via hand-to-mouth contact accounted for over 99%of the total exposure risk although overall exposure was lower than threshold acceptable levels for carcinogenic and non-carcinogenic metals,indicating an overall lack of risk towards human health.Nevertheless,the health risk from atmospheric deposition of PTEs in Caohai Lake may be reduced by focusing on Zn,Pb,and Cd deposition in rainfall and minimizing the hazards associated with hand-to-mouth exposure to PTEs.

Decontamination of Potential Toxic Elements in Sewaged Soils by Inorganic Amendments

This study investigated the feasibility of using some natural clay minerals available in Egypt like kaolinite, bentonite, also using of iron oxide, rock phosphate and mixture of these types to minimize the rate of Ni, Cu, Zn and Mn desorption from sewage soils and to evaluate the effect of these mixtures on Zn equivalent constant values before and after remediation. The obtained results indicated that all mixtures used were minimizing the rate of potential toxic elements （PTE＇s） release from sewage soils compared to control treatment. According to the decreasing order of different treatments, data indicated that application of the mixture treatment of bentonite, kaolinite and rock phosphate （RP） in sewage soils becomes the best treatment compared to other treatments used. However, the lowest and save Zn equivalent constant value which represents the hazard indicator in the study was observed in sewage soil treated with the mixture of bentonite and RP. The kinetic constants of Elovich, modified Freundlich and Hoerl equations, the best fitted models, were significantly decreased compared to control treatments with different percent of minimization according to type of pollutants and remediation material used. To understand the mechanisms of PTE＇s retained in treated sewage soil, distribution study was applied which showed that different pollutants studied were removed to hardly available form different mechanisms of PTE＇s undergo in treated sewage soils were discussed in the study.

Using cemented paste backfill to tackle the phosphogypsum stockpile in China:A down-to-earth technology with new vitalities in pollutant retention and CO_(2) abatement

Phosphogypsum(PG),a hard-to-dissipate by-product of the phosphorus fertilizer production industry,places strain on the biogeochemical cycles and ecosystem functions of storage sites.This pervasive problem is already widespread worldwide and requires careful stewardship.In this study,we review the presence of potentially toxic elements(PTEs)in PG and describe their associations with soil properties,anthropogenic activities,and surrounding organisms.Then,we review different ex-/in-situ solutions for promoting the sustainable management of PG,with an emphasis on in-situ cemented paste backfill,which offers a cost-effective and highly scalable opportunity to advance the value-added recovery of PG.However,concerns related to the PTEs'retention capacity and long-term effectiveness limit the implementation of this strategy.Furthermore,given that the large-scale demand for ordinary Portland cement from this conventional option has resulted in significant CO_(2) emissions,the technology has recently undergone additional scrutiny to meet the climate mitigation ambition of the Paris Agreement and China's Carbon Neutrality Economy.Therefore,we discuss the ways by which we can integrate innovative strategies,including supplementary cementitious materials,alternative binder solutions,CO_(2) mineralization,CO_(2) curing,and optimization of the supply chain for the profitability and sustainability of PG remediation.However,to maximize the co-benefits in environmental,social,and economic,future research must bridge the gap between the feasibility of expanding these advanced pathways and the multidisciplinary needs.

Rapid detection and risk assessment of soil contamination at lead smelting site based on machine learning

A general prediction model for seven heavy metals was established using the heavy metal contents of 207soil samples measured by a portable X-ray fluorescence spectrometer(XRF)and six environmental factors as model correction coefficients.The eXtreme Gradient Boosting(XGBoost)model was used to fit the relationship between the content of heavy metals and environment characteristics to evaluate the soil ecological risk of the smelting site.The results demonstrated that the generalized prediction model developed for Pb,Cd,and As was highly accurate with fitted coefficients(R~2)values of 0.911,0.950,and 0.835,respectively.Topsoil presented the highest ecological risk,and there existed high potential ecological risk at some positions with different depths due to high mobility of Cd.Generally,the application of machine learning significantly increased the accuracy of pXRF measurements,and identified key environmental factors.The adapted potential ecological risk assessment emphasized the need to focus on Pb,Cd,and As in future site remediation efforts.

Contamination assessment,source apportionment and associated health risks of PTEs in agricultural soil under five land-use patterns in Sanya,China

To understand the levels of potentially toxic elements(PTEs)contamination in soils and their effects on human health from different agricultural land use in Sanya,China.128 soil samples(64 topsoil samples and corresponding subsoil samples)were collected from the five representative land-use patterns.Inductively coupled plasma mass spectrometry(ICP-MS),Atomic fluorescence spectrometry(AFS),and Inductively coupled plasma optical emission spectrometry(ICP-OES)were used to determine the content of PTEs(As,Cd,Hg,Cu,Cr,Ni,Pb,Zn,Co,Mo,Sb,and V).Correlation analysis and factor analysis were used to determine the source of PTEs.Geo-accumulation index(I_(geo)),hazard quotient(HQ),and total carcinogenic risk index(TR)were used to measure the PTEs contamination and its relative health impacts.Results showed that the average values of 12 PTEs in topsoil were higher than the Hainan soil geochemical baseline,showing different degrees of PTEs accumulation effect.The concentration of PTEs in the topsoil was lower than those in the subsoil except for Cd and Hg.The I_(geo)revealed that the major accumulated element in soils was As followed by Mo.Source apportionment suggested that parent materials and agricultural practices were the dominant factors for PTEs accumulation in the topsoil.Noncarcinogenic risks of soil samples from five land-use patterns presented a trend of paddy field>dry field>woodland>orchard>garden plot.However,the HQ values of 12 PTEs were less than the recommended limit of HQ=1,representing that there are no non-carcinogenic risks of PTEs for children and adults in the study area.The TR values are within 6.95×10^(-6)-1.38×10^(-5),which corresponds to the low level.Therefore the PTEs in the agricultural soil of the study area show little influence on the health status of the local population.

Microbial responses towards biochar application in potentially toxic element(PTE)contaminated soil:a critical review on effects and potential mechanisms

Soil harbors a huge diversity of microorganisms and serves as the ecological and social foundation of human civilization.Hence,soil health management is of utmost and consistent importance,aligning with the United Nations Sustainable Development Goals.One of the most hazardous contaminants in soil matrix is potentially toxic elements(PTEs),which can cause stress in soil indigenous microorganisms and severely jeopardize soil health.Biochar technology has emerged as a promising means to alleviate PTE toxicity and benefit soil health management.Current literature has broadly integrated knowledge about the potential consequences of biochar-amended soil but has focused more on the physical and chemical responses of the soil system than microbiological attributes.In consideration of the indispensable roles of soil microbials,this paper first introduces PTE-induced stresses on soil microbials and then proposes the mechanisms of biochar’s effects on soil microbials.Finally,microbial responses including variations in abundance,interspecific relationships,community composition and biological functions in biochar-amended soil are critically reviewed.This review thus aims to provide a comprehensive scientific view on the effect of biochar on soil microbiological health and its management.

Risk Assessment of Human Exposure to 2-Methylnaphthalene, Phenanthrene and Didodecylphthalate via Consumption of Shrimps (Macrobrachium vollenhovenii) from Qua Iboe River Estuary, South-South Nigeria

Ibeno, one of the major oil producing communities in South-South Nigeria is a coastal commercial fishery hub that houses Axon-Mobil operational base and pharmaceutical/plastic industries. Shrimp species (Macrobrachium vollenhovenii) is a major aquatic food frequently consumed by inhabitants of the coastal area and those living hinterland, thus, being a major route of human exposure to 2-methylnaphthalene, phenanthrene and didodecyl phthalate in the area. The purpose of the study was to evaluate factors that determine bioaccumulation and assess the potential cancer and non-cancer risk posed by these contaminants through human (adult and children) exposure via shrimp’s consumption using gas chromatography-mass spectroscopy. The associated sediment showed higher mean concentrations of 2-methylnaphthalene, phenanthrene and didodecylphthalate at the two sites relative to those in fresh shrimp samples and factors such as size, lipid content, physicochemical property and environmental condition influenced the uptake of these contaminants. Besides water loss, the traditional drying process enhanced the levels of phenanthrene and didodecylphthalate in dry shrimps most likely due to combustion process and relatively low volatility, respectively and lowered the level of 2-methylnapthalene linked to its relatively high volatility. The potential of cancer and non-cancer development in human were highest via dry large shrimp consumption and followed the sequence: dry small shrimp > fresh large shrimp > fresh small shrimp and were within the USEPA reference standards. Although children were more vulnerable, the exposed individuals may not exhibit notable health-associated adverse effects in the near future. Thus, adequate advocacy is needed to sensitize those living in the catchments who often prefer dry shrimp in their meals on the adverse health implications of these contaminants for their survival and the need to maintain the health of the ecosystem.

Acute toxicity formation potential of benzophenone-type UV filters in chlorination disinfection process

Benzophenones （BPs） are a class of widely used UV filters, which have been frequently detected within multiple environmental matrices. Disinfection is a necessary process in water treatment processes. The transformation behaviors and toxicity changes of 14 BP-type UV filters during chlorination disinfection treatment were investigated in this study. A new index, the acute toxicity formation potential, was proposed to evaluate the toxicity changes and potential risks of BP-type UV filters during chlorination treatment. It was found that 13 of 14 BP-type UV filters exhibited toxicity decreases in the chlorination disinfection process, more or less, while one showed a toxicity increase. The toxicity changes were dependent on substitution effects, such that 2,4-di-hydroxylated or 3-hydroxylated BPs exhibited significant toxicity decreases after chlorination treatment due to the ready cleavage of the aromatic ring. Importantly, the acute toxicity changes could be duplicated in an ambient water matrix.

Extraction of Cd and Pb from contaminated-paddy soil with EDTA, DTPA, citric acid and FeCl3 and effects on soil fertility

Potentially toxic metals,Cd and Pb in paddy soil,have important meanings for safety of rice.A comparison extraction of Cd and Pb with EDTA,DTPA,citric acid,and FeCl3 and effects on soil fertility was studied.Results indicate that about 59%and 63%of soil Cd and Pb were simultaneously removed by 10 g/L EDTA at pH 5 with a soil/extractant ratio of 1:10(W/V)for 30 min while 52%and 51%by 5 g/L DTPA.Acid extractable and reducible Cd by EDTA and DTPA contributed 58%and 53%of the removals and acid extractable and reducible Pb were about 49%and 41%,respectively.Slight changes of soil fertility,including pH,cation exchange capacity,organic matter,and soil extractable phosphorus,were observed.Extractions of citric acid and ferric chloride,however,were only efficient for Cd and the soil pH was decreased significantly.This study suggests that EDTA and DTPA can be considered as suitable agents to clean up the paddy soils contaminated with potentially toxic metals.

Control of aliphatic halogenated DBP precursors with multiple drinking water treatment processes： Formation potential and integrated toxicity

The comprehensive control efficiency for the formation potentials（FPs） of a range of regulated and unregulated halogenated disinfection by-products（DBPs）（including carbonaceous DBPs（C-DBPs）, nitrogenous DBPs（N-DBPs）, and iodinated DBPs（I-DBPs）） with the multiple drinking water treatment processes, including pre-ozonation, conventional treatment（coagulation–sedimentation, pre-sand filtration）, ozone-biological activated carbon（O_3-BAC） advanced treatment, and post-sand filtration, was investigated. The potential toxic risks of DBPs by combing their FPs and toxicity values were also evaluated.The results showed that the multiple drinking water treatment processes had superior performance in removing organic/inorganic precursors and reducing the formation of a range of halogenated DBPs. Therein, ozonation significantly removed bromide and iodide,and thus reduced the formation of brominated and iodinated DBPs. The removal of organic carbon and nitrogen precursors by the conventional treatment processes was substantially improved by O_3-BAC advanced treatment, and thus prevented the formation of chlorinated C-DBPs and N-DBPs. However, BAC filtration leads to the increased formation of brominated C-DBPs and N-DBPs due to the increase of bromide/DOC and bromide/DON.After the whole multiple treatment processes, the rank order for integrated toxic risk values caused by these halogenated DBPs was haloacetonitriles（HANs）》haloacetamides（HAMs） 〉haloacetic acids（HAAs） 〉 trihalomethanes（THMs） 〉 halonitromethanes（HNMs） 》I-DBPs（I-HAMs and I-THMs）. I-DBPs failed to cause high integrated toxic risk because of their very low FPs. The significant higher integrated toxic risk value caused by HANs than other halogenated DBPs cannot be ignored.

The concentration and probabilistic risk assessment of potentially toxic elements in fillets of silver pomfret(Pampus argenteus):A global systematic review and meta-analysis

The contamination of fish type products such as silver pomfret fish fillets by potentially toxic elements(PTEs)has raised global health concerns.Related studies regarding the concentration of PTEs in fillets of silver pomfret fish were retrieved among some international databases such as Scopus,Pub Med and Embase between 1 January 1983 and 10 March 2020.The pooled(mean)concentration of PTEs in fillets of silver pomfret fish was meta-analyzed with the aid of a random-effect model(REM).Also,the non-carcinogenic risk was estimated via calculating the 95 th percentile of the total target hazard quotient(TTHQ).The meta-analysis of 21 articles(containing 25 studies or data reports)indicated that the ranking of PTEs in fillets of silver pomfret fish was Fe(11,414.81μg/kg wet weight,ww)>Zn(6055.72μg/kg ww)>Cr(1825.79μg/kg ww)>Pb(1486.44μg/kg ww)>Se(1053.47μg/kg ww)>Cd(992.50μg/kg ww)>Ni(745.23μg/kg ww)>Cu(669.71μg/kg ww)>total As(408.24μg/kg ww)>Co(87.03μg/kg ww)>methyl Hg(46.58μg/kg ww).The rank order of health risk assessment by country based on the TTHQ for adult consumers was Malaysia(2.500)>Bangladesh(0.886)>Iran(0.144)>China(0.045)>Pakistan(0.020)>India(0.015),while the corresponding values for child consumers was Malaysia(11.790)>Bangladesh(4.146)>Iran(0.675)>China(0.206)>Pakistan(0.096)>India(0.077).The adult consumers in Malaysia and children in Malaysia and Bangladesh were at considerable non-carcinogenic risk.Therefore,following the recommended control plans in order to reduce the health risk associated with the ingestion of PTEs via consumption of silver pomfret fish fillets is crucial.

Fine Particulate Matter and Heavy Metals Pollution Status in Ambient Air of Some Selected Industrial Sites in Northern Nigeria

Fine particulate matter and eight heavy metals (Ni, Co, Cu, Pb, Cd, Cr, Mn, and Zn) concentrations were determined in air samples collected from three industrial sites in northern Nigeria using a Handheld Portable Particle Counter for PM2.5 and PM10 with model number CW-HAT 200 and a High Volume Respirable Dust Sampler (APM 460 NL) in conjunction with an Atomic Absorption Spectrophotometer (Serial No. AA0904M046) Flame Test. The results of the fine particulates ranged from 11.0 - 46.0 μg.m-3 for PM2.5 and 22.0 - 88 μg.m-3 for PM10 across all the industrial sites investigated. Most of these results exceeded the WHO permissible levels of 25.0 μg.m-3 and 50.0 μg.m-3 for PM2.5 and PM10 and thus pose threats to people living and working close to these sites. The concentration of the heavy metals studied were found to be within WHO/EU set standards except for the concentrations of Ni, Pb, and Cd that exceeded the set standard by WHO/EU with toxicity potential >1 in the Terytex industry, Kano and Grand Cereals, Jos. Strong positive correlations were found between the fine particulates concentrations and heavy metals in all the studied sites suggesting that common anthropogenic sources contributed to the fine particulates and heavy metals recorded from the industrial areas. We suggested the installation of electrostatic precipitators to combat fine particulates emission from the stack and also recommended a proper legislative framework by the government to regulate and control industrial fugitive emissions to protect human health.

Preliminary Study of Groundwater Quality Using Hierarchical Classification Approaches for Contaminated Sites in Indigenous Communities Associated with Crude Oil Exploration Facilities in Rivers State, Nigeria

Background: Groundwater is an important source of water. Since the control and removal of pollution are expensive, it is essential to identify the possible sources of contamination and to correctly classify groundwater on the basis of its intrinsic and integrated vulnerability. Objectives: To group ground water chemical ions and heavy metals parameters into similar groups. Method: The investigation made use of standard analytical procedures. All sampling, conservation, transportation and analysis followed standard procedures described in APHA (2012). To prevent degradation of the organic substances, all obtained samples were transferred to the laboratory, while kept in an icebox. Results: Sampling records from the same area are generally assigned to the same cluster during hierarchical cluster analysis (HCA). The cluster diagram shows the grouping of the heavy metal in the study area during wet and dry seasons. It reveals that 5 distinct clusters were identified for wet season and 4 clusters were identified during dry season. Also, it reveals that 5 distinct clusters were identified for wet season and for dry season, 4 distinct clusters were identified. Conclusion: The findings of this study are significant for policymakers and agencies in terms of dealing with the issues identified to enhance sustainable livelihood practices in the oil rich Niger Delta region of Nigeria. Therefore, decision-makers should take proper initiatives to get local people aware of the endangered zones before use, as drinking water is key to good health. Similarly, multinational oil companies will find it useful in their quest for viable social corporate responsibility and remediation plans in their respective host communities. The method proved to be a useful and objective tool for environmental planning.

Heavy metal: a misused term?

The use of the term"heavy metal"is regularly questioned by the scientific community.Here,we followed the evolution(1970–2020)in the number of published papers including this term in their title.Thus,we can evidence a continuous,albeit sometimes stabilizing,increase especially in environmental journals.After several other warning opinions,we propose that it should be replaced in the scientific literature by terms like"metal","metalloid","trace metal elements"or"potentially toxic element".

Psychoactive Chemical Constituents of Carissa edulis (Forssk.) Vahl Roots and Its Safety Limits in Folk Treatment: Benzodiazepines Analogous

Carissa edulis Vahl is well known in Sudanese herbal medicine,commonly used for treatment of epilepsy,headache,chest pains,rheumatism,skin lesions,mania and other psychoactive diseases.The investigations of the safety use for psychoactive purposes in Sudanese healing traditions and identifying secondary metabolites of the plant extracts are the key steps towards determination of appropriate medicinal doses.Therefore,one of the chemical constituents was isolated and structurally identified by 1H-NMR and LC-MS.With the aim of evaluating Carissa edulis folk random uses,the isolated compound was compared with reference artificial drugs Lormetazepam,a potentially toxic compound.Structure investigations confirm that the isolated product was benzodiazepines analogous 7-chloro 1,4-benzodiazepine-2-ones.It is important to know the potential toxicity of certain plant in order to assess the therapeutic effect of it,as these are slight distinctions between the medicinal and toxic doses.In general the results obtained justify the use of the roots of Carissa edulis in traditional medicine for the treatment of some psychiatric diseases.

Concentrated Standing Tailwater： A Mechanism for Nutrient Delivery to Downstream Aquatic Ecosystems

Contribution of first flush runoff events from intense rainfall to downstream aquatic ecosystems are often reported in terms of sediment and nutrient delivery, with hardly any consideration to the contribution that standing, concentrated tailwater in primary aquatic systems makes to downstream nutrient loads. Two geographically distinct studies （Jonesboro Arkansas, and Stoneville Mississippi; 4 studies, n = 30） evaluated the effectiveness of drainage ditch systems to mitigate nutrient concentrations and loads. Within each independent study all experimental ditches had elevated background nutrient concentrations as a result of standing water, prior to the start of each simulated runoff experiment. These concentrations remained elevated 15-30 minutes post the start of each simulation as the concentrated, impounded water was pushed out through each system. In both these systems, it was hypothesized that water had accumulated in the respective drainage ditches and had been concentrated though evaporation and aquatic macrophyte transpiration. It is theorized that additional controlled drainage with improved dilution and hydraulic residence management.