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1.
J Infect Dis ; 2024 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-38700101

RESUMEN

We evaluated hair tenofovir (TFV) concentrations as an adherence metric for HIV pre-exposure prophylaxis (PrEP) during pregnancy and postpartum and compared hair levels with tenofovir-diphosphate (TFV-DP) levels in dried blood spots (DBS). Overall, 152 hair samples from 102 women and 36 hair-DBS paired samples from 29 women were collected from a subset of women in a cluster randomized trial. Having a partner known to be living with HIV was associated with higher hair TFV levels (p<0.001). Hair TFV concentrations were strongly correlated with DBS TFV-DP levels (r=0.76, p<0.001), indicating hair as promising cumulative adherence metric for perinatal PrEP assessment.

2.
Front Reprod Health ; 5: 1205503, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38045529

RESUMEN

Background: Pre-exposure prophylaxis (PrEP) is recommended by the World Health Organization and the Kenyan Ministry of Health for HIV prevention in pregnancy and postpartum for women at risk for HIV. Integration of PrEP into antenatal care is promising, but delivery gaps exist in the face of healthcare provider shortages in resource-limited settings. Methods: Between May and November 2021, we conducted a difference-in-differences study (3 months pre-intervention data collection and 3 months post-intervention data collection) analyzing four intervention facilities, where the strategies were implemented, and four comparison facilities, where no strategies were implemented. We tested a combination of three implementation strategies-video-based PrEP information in the waiting bay, HIV self-testing, and dispensing of PrEP in the antenatal care rooms-to improve PrEP delivery. We compared absolute changes in the proportion of antenatal attendees screened for PrEP (PrEP penetration), the proportion receiving all PrEP-specific steps in a visit (HIV testing, risk screening, and PrEP counseling) (PrEP fidelity), and client PrEP knowledge, client satisfaction, and waiting time and service time (a priori outcomes); post hoc, we compared the proportion offered PrEP (PrEP offer) and completing HIV testing. We measured provider perceptions of the acceptability and appropriateness of the implementation strategies. Results: We observed significant improvements in PrEP penetration, PrEP offer, satisfaction, and knowledge (p < 0.05) and improvements in fidelity that trended towards significance (p = 0.057). PrEP penetration increased 5 percentage points (p = 0.008), PrEP fidelity increased 8 percentage points (p = 0.057), and PrEP offer increased 4 percentage points (p = 0.003) in intervention vs. comparison facilities. Client PrEP knowledge increased by 1.7 out of 6 total points (p < 0.001) and client satisfaction increased by 0.7 out of 24 total points (p = 0.003) in intervention vs. comparison facilities. We observed no changes in service time (0.09-min decrease; p = 0.435) and a small increase in waiting time (0.33-min increase; p = 0.005). HIV testing among those eligible did not change (1.5 percentage point decrease, p = 0.800). Providers felt the implementation strategies were acceptable and appropriate (median acceptability: 20/20; median appropriateness: 19.5/20). However, absolute levels of each step of the PrEP cascade remained suboptimal. Conclusions: An implementation strategy package with video information, HIV self-testing, and co-location of medication dispensing enhanced PrEP delivery across several implementation outcomes and client satisfaction, while not substantially increasing wait time or decreasing provider-client contact time. Clinical trial registration: ClinicalTrials.gov , identifier, NCT04712994.

3.
Implement Sci Commun ; 4(1): 93, 2023 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-37580795

RESUMEN

BACKGROUND: There is a higher risk for HIV acquisition during pregnancy and postpartum. Pre-exposure prophylaxis (PrEP) is recommended during this period for those at high risk of infection; integrated delivery in maternal and child health (MCH) clinics is feasible and acceptable but requires implementation optimization. METHODS: The PrEP in Pregnancy, Accelerating Reach and Efficiency study (PrEPARE; NCT04712994) engaged stakeholders to prioritize determinants of PrEP delivery (using Likert scores) and prioritize PrEP delivery implementation strategies. Using a sequential explanatory mixed methods design, we conducted quantitative surveys with healthcare workers at 55 facilities in Western Kenya and a stakeholder workshop (including nurses, pharmacists, counselors, and county and national policymakers), yielding visual plots of stakeholders' perceived feasibility and effectiveness of the strategies. A stepwise elimination process was used to identify seven strategies for empirical testing. Facilitator debriefing reports from the workshop were used to qualitatively assess the decision-making process. RESULTS: Among 146 healthcare workers, the strongest reported barriers to PrEP delivery were insufficient providers and inadequate training, insufficient space, and high volume of patients. Sixteen strategies were assessed, 14 of which were included in the final analysis. Among rankings from 182 healthcare workers and 44 PrEP policymakers and implementers, seven strategies were eliminated based on low post-workshop ranking scores (bottom 50th percentile) or being perceived as low feasibility or low effectiveness for at least 50% of the workshop groups. The top seven strategies included delivering PrEP within MCH clinics instead of pharmacies, fast-tracking PrEP clients to reduce waiting time, delivering PrEP-related health talks in waiting bays, task shifting PrEP counseling, task shifting PrEP risk assessments, training different providers to deliver PrEP, and retraining providers on PrEP delivery. All top seven ranked strategies were grouped into bundles for subsequent testing. Facilitator debriefing reports generally aligned with rankings but noted how stakeholders' decision-making changed when considering the impact of strategies on facility staff and non-PrEP clients. CONCLUSIONS: The most impactful barriers to integrated PrEP delivery in MCH clinics were insufficient staffing and space. Implementation strategies prioritized through multiple methods of stakeholder input focused on co-location of services and increasing clinic efficiency. Future testing of these stakeholder-prioritized strategy bundles will be conducted to assess the effectiveness and implementation outcomes.

4.
Front Reprod Health ; 5: 1206150, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37484872

RESUMEN

Background: Risk of HIV acquisition is high during pregnancy and postpartum, and pre-exposure prophylaxis (PrEP) is recommended for peripartum populations. Integrating PrEP into maternal and child health (MCH) clinics is feasible and acceptable. Understanding clinics' service availability and readiness is essential for effective scale up. Methods: The PrEP in Pregnancy, Accelerating Reach and Efficiency study (PrEPARE; NCT04712994) engaged PrEP-experienced facilities previously linked to a programmatic or research study in Western Kenya to document available services and commodities via a modified service availability and readiness assessment (SARA) survey with 20 PrEP tracer items covering: staffing/guidelines, services/equipment, and medicines/commodities. Facilities' prior study engagement occurred between 2017 and 2019; SARA survey data was collected between April 2020 and June 2021. Descriptive statistics were stratified by prior study engagement. ANOVA tests assessed associations between facility characteristics and gaps. Fisher's tests assessed differences in commodity availability and stockouts. Results: Of the 55 facilities surveyed, 60% had received PrEP training in the last two years, 95% offered PrEP integrated into MCH, and 64% and 78% had both auditory and visual privacy in PrEP and HIV testing service (HTS) delivery spaces, respectively. Supervision frequency was heterogeneous, but 82% had received a supervision visit within 3 months. Availability of commodities was variable and the most commonly unavailable commodities were PrEP in MCH (71% available) and risk assessment screening tool (RAST) and PrEP cards (60% and 75% available, respectively). The number of service and commodity gaps per facility ranged from zero to eight (median: 3; IQR: 2, 5). The most frequent gaps were: PrEP training and risk assessment cards (40% each), lack of privacy in PrEP (36%) and HIV testing services (31%) spaces, PrEP pills in MCH (29%), and PrEP cards (25%). There were no differences in mean number of gaps by county, previous study engagement, or public vs. private status. Level 4 facilities had fewer gaps (mean 2.2) than level 2, 3, and 5 facilities (mean 5.7, 4.5, and 5.3 respectively; p < 0.001). Conclusions: PrEP service availability and readiness was generally high across MCH facilities. However, there is a need for increased frequency of provider training and supportive supervision focused on fidelity. To address key commodity stockouts such as PrEP pills, implementation of electronic logistics management information systems may be needed. Targeting these gaps is essential to effectively scale up integrated PrEP delivery, especially among facilities with limited infrastructure.

5.
Implement Sci Commun ; 4(1): 76, 2023 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-37438779

RESUMEN

BACKGROUND: There is a lack of consensus about how to prioritize potential implementation strategies for HIV pre-exposure prophylaxis (PrEP) delivery. We compared several prioritization methods for their agreement and pragmatism in practice in a resource-limited setting. METHODS: We engaged diverse stakeholders with clinical PrEP delivery and PrEP decision-making experience across 55 facilities in Kenya to prioritize 16 PrEP delivery strategies. We compared four strategy prioritization methods: (1) "past experience surveys" with experienced practitioners reflecting on implementation experience (N = 182); (2 and 3) "pre- and post-small-group ranking" surveys before and after group discussion (N = 44 and 40); (4) "go-zone" quadrant plots of perceived effectiveness vs feasibility. Kendall's correlation analysis was used to compare strategy prioritization using the four methods. Additionally, participants were requested to group strategies into three bundles with up to four strategies/bundle by phone and online survey. RESULTS: The strategy ranking correlation was strongest between the pre- and post-small-group rankings (Tau: 0.648; p < 0.001). There was moderate correlation between go-zone plots and post-small-group rankings (Tau: 0.363; p = 0.079) and between past-experience surveys and post-small-group rankings (Tau: 0.385; p = 0.062). For strategy bundling, participants primarily chose bundles of strategies in the order in which they were listed, reflecting option ordering bias. Neither the phone nor online approach was effective in selecting strategy bundles. Participants agreed that the strategy ranking activities conducted during the workshop were useful in prioritizing a final set of strategies. CONCLUSIONS: Both experienced and inexperienced stakeholder participants' strategy rankings tended to prioritize strategies perceived as feasible. Small group discussions focused on feasibility and effectiveness revealed moderately different priorities than individual rankings. The strategy bundling approach, though less time- and resource-intensive, was not effective. Future research should further compare the relative effectiveness and pragmatism of methodologies to prioritize implementation strategies.

6.
AIDS ; 37(11): 1725-1737, 2023 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-37289583

RESUMEN

OBJECTIVE: We evaluated pre-exposure prophylaxis (PrEP) initiation, persistence, and adherence measured via tenofovir-diphosphate (TFV-DP) concentrations in dried blood spots (DBS) among women offered PrEP during pregnancy. METHODS: We prospectively analyzed data from participants in the PrIMA Study (NCT03070600) who were offered PrEP during the second trimester and followed through 9 months postpartum. At follow-up visits (monthly in pregnancy; 6 weeks, 6 months, 9 months postpartum), self-reported PrEP use was assessed, and DBS were collected for quantifying TFV-DP concentrations. RESULTS: In total, 2949 participants were included in the analysis. At enrollment, median age was 24 years [interquartile range IQR) 21-29], gestational age 24 weeks (IQR 20-28), and 4% had a known partner living with HIV. Overall, 405 (14%) participants initiated PrEP in pregnancy with higher frequency among those with risk factors for HIV acquisition, including >2 lifetime sexual partners, syphilis during pregnancy, forced sex, and intimate partner violence ( P  < 0.05). At 9 months postpartum, 58% of PrEP initiators persisted with PrEP use, of which 54% self-reported not missing any PrEP pills in the last 30 days. Among DBS randomly selected from visits where participants persisted with PrEP ( n  = 427), 50% had quantifiable TFV-DP. Quantifiable TFV-DP was twice as likely in pregnancy than postpartum [adjusted risk ratio (aRR) = 1.90, 95% confidence interval (CI) 1.40-2.57, P  < 0.001]. Having a partner known to be living with HIV was the strongest predictor of PrEP initiation, persistence, and quantifiable TFV-DP ( P  < 0.001). CONCLUSIONS: PrEP persistence and adherence waned postpartum, though over half of PrEP initiators persisted through 9-months postpartum. Interventions should prioritize increasing knowledge of partner HIV status and sustaining adherence in the postpartum period.


Asunto(s)
Fármacos Anti-VIH , Infecciones por VIH , Profilaxis Pre-Exposición , Femenino , Humanos , Lactante , Embarazo , Fármacos Anti-VIH/uso terapéutico , Infecciones por VIH/tratamiento farmacológico , Cumplimiento de la Medicación , Periodo Posparto , Estudios Prospectivos
7.
Paediatr Perinat Epidemiol ; 37(6): 489-504, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37186316

RESUMEN

BACKGROUND: Evidence gaps remain regarding the influence of prenatal psychosocial factors on adverse pregnancy outcomes. OBJECTIVE: The objective of this study is to evaluate relationships between psychosocial factors and adverse perinatal outcomes among Kenyan women. METHODS: We analysed data from a prospective cohort study enrolling HIV-negative women in pregnancy (NCT03070600) in 20 antenatal clinics in Western Kenya. Study nurses assessed depressive symptoms using the Center for Epidemiologic Studies Depression Scale (CESD-10), social support using the Medical Outcomes Survey scale (MOS-SSS), intimate partner violence (IPV) with the Hurt, Insult, Threaten, Scream scale (HITS), and pregnancy outcomes at 6 weeks postpartum. Cox proportional hazards models were used to evaluate relationships between depressive symptoms (moderate-to-severe [MSD, CESD-10 ≥10] and mild-to-severe [Mild-SD, CESD-10 ≥5]), low social support (MOS-SSS <72), and IPV (HITS ≥10) with adverse perinatal outcomes of pregnancy loss, stillbirth, preterm birth (PTB), small for gestational age, and neonatal mortality. We also estimated the population attributable risk. RESULTS: Among 4153 women, 23.9% (n = 994) had MSD, 54.7% (n = 2273) mild-SD, 37.3% (n = 1550) low social support, and 7.8% (n = 323) experienced IPV. Pregnancy loss was 5-fold higher among women with MSD (adjusted hazard ratio [HR] 5.04, 95% confidence interval [CI] 2.44, 10.42); 37.4% of losses were attributable to MSD. Mild-SD was associated with PTB (HR 1.39, 95% CI 1.03, 1.87). Stillbirth risk more than doubled among women reporting low social support (HR 2.37, 95% CI 1.14, 4.94). CONCLUSIONS: Adverse perinatal outcomes were common and associated with prenatal depressive symptoms and low social support in this large cohort of Kenyan mother-infant pairs.


Asunto(s)
Aborto Espontáneo , Nacimiento Prematuro , Recién Nacido , Embarazo , Lactante , Femenino , Humanos , Mortinato/epidemiología , Kenia/epidemiología , Depresión/epidemiología , Estudios Prospectivos , Nacimiento Prematuro/epidemiología
9.
JMIR Res Protoc ; 12: e41170, 2023 01 30.
Artículo en Inglés | MEDLINE | ID: mdl-36716092

RESUMEN

BACKGROUND: Cisgender women in Kenya are at elevated risk of HIV acquisition during pregnancy and post partum. Acute HIV infection during pregnancy and breastfeeding accounts for approximately one-third of all vertical HIV transmissions. The World Health Organization recommends offering oral tenofovir-based pre-exposure prophylaxis (PrEP) to pregnant and postpartum women who are HIV negative but at substantial and ongoing risk for HIV acquisition. PrEP delivery for pregnant and postpartum women is expanding within routine maternal child health clinics in Kenya. However, approximately half of pregnant women discontinue PrEP within 30 days of initiation. Therefore, it is crucial to develop PrEP adherence strategies that enhance support for adherence when peripartum events and health issues pose challenges to sustaining PrEP adherence. OBJECTIVE: We are conducting a randomized controlled trial to determine the effect of a bidirectional communication platform named Mobile Solutions for Women's and Children's Health (mWACh), which utilizes two-way SMS text messaging between patients and remote nurses to support PrEP adherence and address maternal health concerns in real time during the peripartum period. METHODS: The mWACh-PrEP study is a randomized trial designed to support PrEP adherence during the peripartum period by comparing mWACh-PrEP to the standard of care (ie, in-clinic adherence counseling) among women who are HIV negative and initiating PrEP. Purposive sampling was used to select 5 facilities offering PrEP in antenatal clinics in Kisumu and Siaya Counties, and block randomization will be used to divide participants into groups. Participants in the intervention arm will receive a customized messaging curriculum via SMS text messages targeted toward their particular perinatal stage. The primary outcome, PrEP adherence at 6 months post partum, will be evaluated using a log-binomial regression model, adjusting for imbalanced baseline characteristics. Based on a previous study of directly observed dosing conditions, we will use a hair tenofovir concentration cutoff of 0.038 ng/mg (corresponding to 7 doses/week) as the primary adherence outcome measured at 6 months post partum (binary outcome). Qualitative interviews and cost-effective analyses will be conducted to understand the feasibility, acceptability, and economic impact of the intervention. RESULTS: Enrollment began in March 2022 and is projected to continue until July 2023, with follow-up through March 2024. The study results are expected to be reported in 2025. CONCLUSIONS: This trial will provide insights into using mobile health to enhance PrEP adherence among pregnant and postpartum mothers. Additionally, the findings will have implications for the use of mobile health technology to improve adherence to other daily medications during the peripartum period. TRIAL REGISTRATION: ClinicalTrials.gov NCT04472884; https://clinicaltrials.gov/ct2/show/NCT04472884. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/41170.

10.
J Affect Disord ; 324: 637-644, 2023 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-36586607

RESUMEN

BACKGROUND: Identifying optimal depression screening tools for use in maternal health clinics could improve maternal and infant health. We compared four tools for diagnostic performance and epidemiologic associations. METHODS: This study was nested in a cluster-randomized trial in Kenya. Women in 20 maternal health clinics were evaluated at 6 weeks postpartum with Center for Epidemiologic Studies Depression Scale (CESD-10), Edinburgh Postnatal Depression Scale (EPDS), Patient Health Questionnaire-9 and -2 (PHQ-9, PHQ-2) for moderate-to-severe depressive symptoms (MSD) [CESD-10 ≥ 10, EPDS≥13, PHQ-9 ≥ 10, or PHQ-2 ≥ 3]. We assessed area under the curve (AUC) per scale (CESD-10, EPDS) against probable major depressive disorder (MDD) using the PHQ-9 scoring algorithm. Associations between MSD and intimate partner violence (IPV) were compared between scales. RESULTS: Among 3605 women, median age was 24 and 10 % experienced IPV. Prevalence of MSD symptoms varied by tool: 13 % CESD-10, 9 % EPDS, 5 % PHQ-2, 3 % PHQ-9. Compared to probable MDD, the CESD-10 (AUC:0.82) had higher AUC than the EPDS (AUC:0.75). IPV was associated with MSD using all scales: EPDS (RR:2.5, 95%CI:1.7-3.7), PHQ-2 (RR:2.3, 95%CI:1.6-3.4), CESD-10 (RR:1.9, 95%CI:1.2-2.9), PHQ-9 (RR:1.8, 95%CI:0.8-3.8). LIMITATIONS: Our study did not include clinical diagnosis of MDD by a specialized clinician, instead we used provisional diagnosis of probable MDD classified by the PHQ-9 algorithm as a reference standard in diagnostic performance evaluations. CONCLUSION: Depression screening tools varied in detection of postpartum MSD. The PHQ-2 would prompt fewer referrals and showed strong epidemiologic association with a cofactor.


Asunto(s)
Depresión Posparto , Trastorno Depresivo Mayor , Femenino , Humanos , Depresión , Depresión Posparto/diagnóstico , Depresión Posparto/epidemiología , Trastorno Depresivo Mayor/diagnóstico , Trastorno Depresivo Mayor/epidemiología , Kenia/epidemiología , Tamizaje Masivo , Cuestionario de Salud del Paciente , Periodo Posparto , Escalas de Valoración Psiquiátrica , Encuestas y Cuestionarios
11.
Environ Sci Pollut Res Int ; 29(8): 11481-11492, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34535864

RESUMEN

Human population growth and subsequent land use intensification are closely linked to contemporary increases in sediment and associated contaminants fluxes to fluvial systems, lakes, reservoirs, and coastal zones worldwide. In most urban areas, reservoirs that are the main source of fresh water supply, if not effectively managed, suffer from water quality decline and loss of capacity associated with accelerated siltation. This study analyzes watershed soil losses and sediment accumulation rates in two reservoirs in the Occoquan river basin, a sub-watershed of the Chesapeake Bay in the suburbs of the greater Washington, DC area. Lake Manassas is located in the upper reaches of the basin, characterized by mixed land use and cover of mostly forest, residential areas, and agriculture, whereas Occoquan Reservoir is located in the more urbanized lower reach of the basin in the heavily populated suburban zone south of Washington, DC. Five sediment cores from each lake were used in 210Pb-based sediment accumulation rates analysis, and GIS-based Revised Soil Loss Equation (RUSLE) model and a sediment delivery ratio (SDR) were used to evaluate basin soil losses and sediment fluxes to the fluvial systems. 210Pb sediment accumulation rate estimates in Occoquan Reservoir range from 0.26 g cm-2 year-1 in the upper reaches to 0.37 g cm-2 year-1 in the lower reaches. Lake Manassas also had comparable accumulation values ranging from 0.22 to 0.40 g cm-2 year-1. RUSLE/SDR estimated watershed sediment fluxes were 0.26 Mg ha-1 year-1 (Mg-mega gram) in the upper watershed, which is significantly higher than 0.07 Mg ha-1 year-1 estimates for the lower reaches of the watershed. The variability in the reservoirs' sediment accumulation rates and basin soil losses reflects the variability of land use and cover, basin slopes, and erosion mitigation efforts within the watershed. The lower reaches, though more urbanized, have well-developed storm drain systems limiting run-off related soil losses. The well-managed riparian zones surrounding both reservoirs also limit sediment fluxes, hence the relatively low sediment accumulation rates. Although surficial sediment sources seem to be well managed, some of these efforts might be associated with the uptick in intrinsic sediment sources, leading to localized high sediment accumulation in the mouth of tributaries draining the high-intensity urban areas of the basin.


Asunto(s)
Sedimentos Geológicos , Lagos , Monitoreo del Ambiente , Humanos , Ríos , Suelo , Virginia
12.
Environ Monit Assess ; 186(3): 1719-33, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24141485

RESUMEN

Anthropogenic forces that alter the physical landscape are known to cause significant soil erosion, which has negative impact on surface water bodies, such as rivers, lakes/reservoirs, and coastal zones, and thus sediment control has become one of the central aspects of catchment management planning. The revised universal soil loss equation empirical model, erosion pins, and isotopic sediment core analyses were used to evaluate watershed erosion, stream bank erosion, and reservoir sediment accumulation rates for Ni Reservoir, in central Virginia. Land-use and land cover seems to be dominant control in watershed soil erosion, with barren land and human-disturbed areas contributing the most sediment, and forest and herbaceous areas contributing the least. Results show a 7 % increase in human development from 2001 (14 %) to 2009 (21.6 %), corresponding to an increase in soil loss of 0.82 Mg ha(-1) year(-1) in the same time period. (210)Pb-based sediment accumulation rates at three locations in Ni Reservoir were 1.020, 0.364, and 0.543 g cm(-2) year(-1) respectively, indicating that sediment accumulation and distribution in the reservoir is influenced by reservoir configuration and significant contributions from bedload. All three locations indicate an increase in modern sediment accumulation rates. Erosion pin results show variability in stream bank erosion with values ranging from 4.7 to 11.3 cm year(-1). These results indicate that urban growth and the decline in vegetative cover has increased sediment fluxes from the watershed and poses a significant threat to the long-term sustainability of the Ni Reservoir as urbanization continues to increase.


Asunto(s)
Monitoreo del Ambiente , Sedimentos Geológicos/análisis , Ríos/química , Suelo/química , Conservación de los Recursos Naturales , Virginia , Movimientos del Agua
13.
Environ Manage ; 41(5): 766-78, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18320265

RESUMEN

Soil erosion is a serious problem in areas with expanding construction, agricultural production, and improper storm water management. It is important to understand the major processes affecting sediment delivery to surficial water bodies in order to tailor effective mitigation and outreach activities. This study analyzes how naturally occurring and anthropogenic influences, such as urbanization and soil disturbance on steep slopes, are reflected in the amount of soil erosion and sediment delivery within sub-watershed-sized areas. In this study, two sub-watersheds of the Rappahannock River, Horsepen Run and Little Falls Run, were analyzed using the Revised Universal Soil Loss Equation (RUSLE) and a sediment delivery ratio (SDR) to estimate annual sediment flux rates. The RUSLE/SDR analyses for Horsepen Run and Little Falls Run predicted 298 Mg/y and 234 Mg/y, respectively, but nearly identical per-unit-area sediment flux rates of 0.15 Mg/ha/y and 0.18 Mg/ha/y. Suspended sediment sampling indicated greater amounts of sediment in Little Falls Run, which is most likely due to anthropogenic influences. Field analyses also suggest that all-terrain vehicle crossings represent the majority of sediment flux derived from forested areas of Horsepen Run. The combined RUSLE/SDR and field sampling data indicate that small-scale anthropogenic disturbances (ATV trails and construction sites) play a major role in overall sediment flux rates for both basins and that these sites must be properly accounted for when evaluating sediment flux rates at a sub-watershed scale.


Asunto(s)
Contaminación Ambiental , Vehículos a Motor Todoterreno , Ríos , Suelo , Virginia
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