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Rural Women Use Indigenous Botanical Knowledge to Enhance Food Security at Dwesa-Cwebe Nature Reserve, South Africa

By Katie Tavenner

Katie Tavenner, a dual-degree doctoral candidate in Rural Sociology and Women's Studies, received an ARC research grant in Fall 2013 for her project entitled "Co-Management Regimes in Protected Areas of South Africa: Implications for Gender Equity in the Forest-Food Security Nexus".

For over 100 years, the communities adjacent to the Dwesa and Cwebe Forests have been caught in a conflict over natural resources. Residents were forcibly removed from the area for decades by Colonial and Apartheid-era governments, and after being declared a Nature Reserve in 1978, locals were fenced out, losing all access to natural resources. Despite the communities winning a land-claim battle in 2001, the current management of the reserve still reflects a “fortress conservation” model, where local people are prohibited from harvesting natural resources, including a variety of forest foods. Remarkably, the indigenous knowledge associated with these foods endures, primarily through the stories, actions, and resistance of local women.

Katie Tavenner, a PhD Candidate in Rural Sociology and Women’s Studies at Penn State University, conducted ethnographic research over eight-months to understand how this indigenous knowledge was being used, valued, and transferred in the everyday lives of smallholder farmers adjacent to the reserve. Through community interviews, participatory photography, and a survey of 80 households in Hobeni Village, the continuing significance of forest foods was documented. The project yielded important information regarding the identification and valuation of forest species – knowledge that was previously undocumented in the area. For example, in a series of participatory workshops held in 2014, fifteen ecological experts were able to identify 64 different species of wild edible plants. About a third of these plants are wild fruits, while the remainder are indigenous vegetables – known locally as “imifino”. About 10 percent of these species are found outside of the forest veld, and many have been partially domesticated by smallholder farmers. A major finding of this research is the local-level innovation associated with transplantation of species as a result of the restrictions placed on forest resource harvesting. Thus, the home garden has become the primary site of food security for households in reserve-adjacent communities – spaces that are dominated by rural women.

Although the number of women entering the formal work-force has increased since the end of Apartheid, domestic responsibilities associated with family nutrition are held almost exclusively by mothers and grandmothers. Findings from this research show that the usage of wild foods contributes greatly to diet diversification and nutrition at the household level, and provides a buffer in times of economic hardship or food shortages. Dependency on these foods will likely increase in the future as the Wild Coast region is expected to be hit hard by climactic changes resulting in shorter planting seasons and drier conditions. And yet, the knowledge associated with wild foods remains invisible in forest management plans at both the local and provincial levels.

The findings of this research highlight the need to document indigenous knowledge, and particularly women’s knowledge, of wild foods to promote food security and management of natural resources at the local, national, and international level.

Katie would like to thank the Africana Research Center, the Dickerson Family, the U.S. Borlaug Fellows Program, Bioversity International, Ronnie Vernooy, Derick Fay, Kuzile Juza, the Donald Woods Foundation, Eastern Cape Parks and Tourism Agency, the Office of International Programs, PSU College of Agriculture and the Interinstitutional Consortium for Indigenous Knowledge (ICIK) for facilitating and financially supporting this study.


An imifino expert collects leaves from domesticated forest species in her home garden in Lalini Village, South Africa.



Social Seed Networks:  Identifying Central Farmers for Equitable Seed Access

By Vincent Ricciardi

Vincent Ricciardi, MSc, Geography, received an ARC research grant in Fall 2012 for his project entitled "Participatory Approach to Sustainable Technologies for Orange and Purple Sweetpotatoes (STOPS) in Northern and Upper East regions of Ghana".

Full article: Ricciardi, Vincent. 2014. Social seed networks: identifying central farmers for equitable seed access. Submitted to Agricultural Systems.


Global food insecurity has never been as prevalent as today. About one-sixth of the developing world’s population lacks access to the sufficient foods needed to maintain healthy, productive lifestyles (FAO 2012). Notably, Sub-Saharan Africa has among the most extreme percentages of food-insecure people, remaining around 33 to 35 percent since 1970 (Mwaniki 2006). Crop biodiversity has decreased 75 percent worldwide since the turn of the 20th century (FAO 2012) and is a leading reason for rural food insecurity in the Global South (Pautasso et al. 2012). Brush (1991) defines ‘agrobiodiversity’ as crop biodiversity that acts as the cohesive social and ecological life-support system - it sustainably supplies food access through promoting healthy topsoil, clean water, air, and carbon sinks. The majority of agrobiodiversity is comprised of farmer varieties that have been bred to thrive in regionally-specific agroecological conditions, make up the majority of subsistence farmers' annual seed grown, and provide dependable seed access of nutrient-rich varieties (Lehesranta et al. 2005; Raigón et al. 2008). Importantly, these farmer varieties are open-pollinated and can be saved for repeated use in upcoming seasons, dramatically reducing overall input costs for resource-poor farmers (Sallah et al. 2007; Tripp and Mensah-Bonsu 2013). Agrobiodiversity decline has been further exacerbated by decreases in landholdings, intensification of farming practices, and introduction of closed-pollinated modern varieties, which cannot be saved each year (Bellon et al. 2011; Pautasso et al. 2012).

Traditionally, agrobiodiversity is maintained by informal seed systems, in which subsistence-based farmers engage in social contracts with one another, exchanging seeds to ensure they have enough to plant each season (Almekinders and Louwaars 1999; McGuire 2007; Louwaars and De Boef 2012). Social relationships, such as kinship alliances, facilitate seed and information exchanges necessary for continual and equal seed access (Badstue et al. 2006; Abay et al. 2011). When there are insufficient yields, farmers rely on their social network to resupply depleted seed stores (Almekinders and Elings 2001). These informal exchange systems have been found resilient to certain levels of ecological shock, such as erratic weather patterns, and social stressors, such as poor quality hybrid varieties that are increasingly replacing traditional varieties to meet market demands (De Boef et al. 2010; Tripp and Mensah-Bonsu 2013). However, as subsistence farmers transition from a barter system to a cash-based economy the magnitude of market-oriented agriculture development of hybrid varieties becomes a leading cause for the decline of traditional varieties (Cromwell and van Oosterhout 2000).



Community-based agrobiodiversity management projects have been at the forefront of integrating informal seed systems into food security initiatives. These projects co-create open-pollinated crops and reintroduce lost varieties. A prevailing critique regarding these projects is that there is unequal distribution of seed to communities - quality seed, when introduced, is not reaching target populations.


The purpose of this study is to identify key farmers who can distribute open-pollinated seed through their existing, diverse social channels. Data was collected and combined from two subsistence-based communities in Northern Ghana. Data includes information across all exchanged crops in the communities in order to understand full social networks of seed exchange. Trust has been a key finding in past studies, indicating farmers are more likely to go to their established exchange channels for new varieties and species of seed (Pautasso et al. 2012). Accounting for an entire seed network accounts for farmers’ built relationships.


This study combines social seed network analysis and regression to allow projects to generalize their results. The identification of central, well-connected famers is crucial for such projects to effectively reach as many producers with the smallest amount of resources. Centrality measures the degree in which an individual is connected to others in his/her network through relationships, experiences, or exchanges of goods and information (Borgatti et al. 2013). Multiple types of centrality measures have been proposed to study informal seed systems (Abay et al. 2011). For instance, ‘degree centrality,’ relates to the number of individuals with whom a single farmer exchanges crop seed. Hence, if a farmer trades seed with four other farmers, the degree centrality score is four. Degree centrality is overly simplistic when determining seed exchange flows for open pollinated seed across multiple growing seasons. ‘Harmonic closeness centrality,’ on the other hand, is a comprehensive measure that identifies individuals who are connected to the highest proportion of other nodes via multiple steps. To understand which types of farmers have the most equitable and efficient seed distribution networks, this study uses harmonic closeness centrality as a dependent variable in an ordinary least squares regression. Additional control variables were wealth, kinship alliances, gender, and geographic location.


Results suggest that harmonic closeness centrality can best be predicted across the study communities by identifying farmers who are geographically centrally located, who have well connected kinship networks, and who are male farmers. While distance and kinship have been identified in non-network studies as essential to seed exchange, this study maps how these two factors affect farmers’ access to quality, open pollinated seed. A critical finding in this study is that males are more central than females, yet have less frequency of seed exchanges. Projects using this method to inform their seed distribution efforts need to consider this gendered power dynamic where the female farmers are responsible for seed saving and exchange activities, while male farmers control access to local seed varieties. These findings validate the utility of social network analysis in unfolding the socioecological complexity of informal seed systems and offer an equitable approach to (re)introducing open-pollinated varieties. Please refer to below figures and forthcoming publication for more detail on results.


Table 1-1: Descriptive statistics

Table 1-1 Descriptive statistics.png

Table 1‑3: Regression output

Table 1‑3 Regression output.png





Figure 5: The number of times crop seed was exchanged by variety across in Aduyuli and Diani’s seed exchange networks.


Figure 5 The number of times crop seed was exchanged by variety across in Aduyuli and Diani’s seed exchange networks.png

Figure 1: Geographic distance between seed exchange partners in Aduyuli; the axis represent latitude and longitude to depict the geographic layout of the communities. Cluster of nodes at the same geographic position represent households with multiple farmers engaged in seed exchange flows. Light grey nodes represents low wealth farmers, darker grey represents medium wealth farmers, and black represents wealthier farmers. Square nodes represent female farmers and circle nodes represent male farmers. The size of the node indicates the farmers level of harmonic closeness centrality. The lines’ widths indicate the amount of seed exchanged between farmers, while the lines’ arrows shows directionality.


Figure 1.png

Figure 2: Geographic distance between seed exchange partners in Diani; the axis represent latitude and longitude to depict the geographic layout of the communities. Cluster of nodes at the same geographic position represent households with multiple farmers engaged in seed exchange flows. Light grey nodes represents low wealth farmers, darker grey represents medium wealth farmers, and black represents wealthier farmers. Square nodes represent female farmers and circle nodes represent male farmers. The size of the node indicates the farmers level of harmonic closeness centrality. The lines’ widths indicate the amount of seed exchanged between farmers, while the lines’ arrows shows directionality.

Figure 2.png

Figure 3: Social distance between seed exchange partners in Aduyuli. Nodal layout is based on the Fruchterman and Reingold (1991) spring embedded algorithm, which lays out each node randomly then uses enables nodes to push and pull one another to find an optimum solution where there is minimal amount of stress on each spring as it connects with the entire network. This algorithm effectively places farmers with higher harmonic closeness centrality towards the center of the sociogram. The size of the node indicates the farmers level of harmonic closeness centrality. The lines’ widths indicate the amount of seed exchanged between farmers, while the lines’ arrows shows directionality. Light grey nodes represents low wealth farmers, darker grey represents medium wealth farmers, and black represents wealthier farmers. Square nodes represent female farmers and circle nodes represent male farmers.

Figure 3.png

Figure 4: Social distance between seed exchange partners in Diani. Nodal layout is based on the Fruchterman and Reingold (1991) spring embedded algorithm, which lays out each node randomly then uses enables nodes to push and pull one another to find an optimum solution where there is minimal amount of stress on each spring as it connects with the entire network. This algorithm effectively places farmers with higher harmonic closeness centrality towards the center of the sociogram. The size of the node indicates the farmers level of harmonic closeness centrality. The lines’ widths indicate the amount of seed exchanged between farmers, while the lines’ arrows shows directionality. Light grey nodes represents low wealth farmers, darker grey represents medium wealth farmers, and black represents wealthier farmers. Square nodes represent female farmers and circle nodes represent male farmers.


Social seed network analysis also reveals that the social makeup of informal seed systems can be detailed, replicated, and used to promote more accessible community-based agrobiodiversity initiatives. The network approach not only echoes that agrobiodiversity goes beyond crop biodiversity and that it is perpetuated and comprised of cohesive social and ecological relationships that sustainably supply food access (Brush 1991). Careful attention needs to be taken when community-based agrobiodiversity development projects start to interact with informal seed systems. Each system has unique characteristics and social network analysis only captures specified relationships, seed exchanges, at one point in time. Other factors and relationships, which may be dynamic over time, most likely affect how farmers continually access seed and disseminate crops to other members in their community. While social seed network analysis makes informal seed systems visible to the researcher, the involved members typically implicitly understand these systems because seed exchange is an integral part of their daily livelihoods (Badstue et al. 2006). Future studies should focus on when and how to make participants aware of their own informal seed access and steps the community can take to make more equal seed distribution possible.



Bellon, M. R., D. Hodson, and J. Hellin. 2011. Assessing the vulnerability of traditional maize seed systems in Mexico to climate change. Proceedings of the National Academy of Sciences 108(33): 13432-13437.

Abay, F., W.S. De Boef, and Å. Bjørnstad. 2011. Network analysis of barley seed flows in Tigray, Ethiopia: supporting the design of strategies that contribute to on-farm management of plant genetic resources. Plant genetic resources 9(4): 495.

Almekinders, C. J. M., and A. Elings. 2001. Collaboration of farmers and breeders: Participatory crop improvement in perspective. Euphytica 122(3): 425-438.

Almekinders, C.J.M., and N.P. Louwaars. 1999. Farmers’ seed production: new approaches and practices. London: Intermediate Technology Publications.

Badstue, L.B., M. R. Bellon, J. Berthaud, X. Juárez, I.M. Rosas, A.M. Solano, and A. Ramírez. 2006. Examining the role of collective action in an informal seed system: a case study from the central valleys of Oaxaca, Mexico. Human ecology 34(2): 249-273.

Bellon, M. R., D. Hodson, and J. Hellin. 2011. Assessing the vulnerability of traditional maize seed systems in Mexico to climate change. Proceedings of the National Academy of Sciences 108(33): 13432-13437.

Borgatti, S.P., M.G. Everett, and L.C. Freeman. 2002. UCINET 6 for Windows: Software for Social Analysis. Harvard, MA: Analytic Technologies.

Borgatti, S.P., G.M. Everett, and C.J. Johnson. 2013. Analyzing Social Networks. Thousand Oaks, CA: Sage.

Brush, S.B. 1991. A farmer-based approach to conserving crop germplasm. Ecology and botany 45(2): 153-165.

Cromwell, E., and S. van Oosterhout. 2000. On-farm Conservation of Crop Diversity: Policy and Institutional Lessons from Zimbabwe. In Genes in the Field: On-farm Conservation of Crop Diversity, ed. S.B. Brush, 217-238. Rome, Italy: IPGRI; Ottawa, Canada: IDRC; Boca Raton, FL: Lewis Publishers. Frankel.

De Boef, W.S., H. Dempewolf, J.M. Byakweli, and J.M. Engels. 2010. Integrating genetic resource conservation and sustainable development into strategies to increase the robustness of seed systems. Journal of sustainable agriculture 34(5): 504-531.

FAO. 2012. The State of Food Insecurity in the World. Food and Agricultural Organization of the United Nations. United Nations. Rome, Italy.

Lehesranta, S.J., H.V. Davies, L.V. Shepherd, N. Nunan, J.W. McNicol, S. Auriola, and S.O. Kärenlampi. 2005. Comparison of tuber proteomes of potato varieties, landraces, and genetically modified lines. Plant physiology 138(3): 1690-1699.

Louwaars, N.P., and W.S. De Boef. 2012. Integrated seed sector development in Africa: a conceptual framework for creating coherence between practices, programs, and policies. Journal crop improvement 26:39–59.

McGuire, S.J. 2007. Vulnerability in farmer seed systems: farmer practices for coping with seed insecurity for sorghum in Eastern Ethiopia. Economic botany 61(3): 221–222.

Mwaniki, A. 2006. Achieving food security in Africa: Challenges and issues. UN Office of the Special Advisor on Africa (OSAA).

Pautasso, M., G. Aistara, A. Barnaud, S. Caillon, P. Clouvel, O.T. Coomes, and S. Tramontini. 2012. Seed exchange networks for agrobiodiversity conservation. A review. Agronomy for sustainable development 33(1): 151-175.

Raigón, M.D., J. Prohens, J.E. Muñoz-Falcón, and F. Nuez. 2008. Comparison of eggplant landraces and commercial varieties for fruit content of phenolics, minerals, dry matter and protein. Journal of food composition and analysis 21(5): 370-376.

Sallah, P., S. Twumasi-Afriyie, K. Ahenkora, K. Asiedu, K. Obeng-Antwi, S. Osie-Yeboah, P. Frimpong-Manso, A. Ankomah, and B. Dzah. 2007. Agronomic potentials of quality protein maize hybrids developed in Ghana. Ghana journal of agricultural science 40: 81-89.

Tripp, R., and A. Mensah-Bonsu. 2013. Ghana’s Commercial Seed Sector. IFPRI. Chicago.



The Racial Gap in Confidence in Science

By Eric Plutzer, Ph.D.

Eric Plutzer, Professor of Political Science., received an ARC research grant in Fall 2012 for his project entitled "Race, Intersectionality, and Alienation from the Scientific Establishment".

Race and Alienation from Science

Compared to whites, African Americans have a long history of alienation from science and scientific institutions.  This history manifests itself not only in the stark under-representation of Blacks in scientific professions, but also quite consistently in attitudes and opinions.

Consider data from the General Social Survey, a longstanding NSF-funded sample survey fielded by the National Opinion Research Center at the University of Chicago.  Combining data from 2006 to 2010, European Americans were nearly one and a half times more likely than Blacks to say that they had “a great deal of confidence” in the people running America’s scientific institutions.  At the other end of the spectrum, African Americans were roughly twice as likely to say that they had “hardly any confidence.

The same study reveals that Blacks were also twice as likely to strongly agree that, “science makes our way of life change too fast,” more than twice as likely to say that “the harmful results of scientific research been greater than its benefits,” and half as likely to agree that “scientific research that advances the frontiers of knowledge is necessary and should be supported by the federal government.”

Now one simple explanation for this is that African Americans display distrust of many powerful institutions.  But this would be incorrect.  This is easily seen in the table below.  The racial gap in confidence in science (13 percentage points)  dwarfs the two-point gap concerning medicine, the zero-point gap concerning banks and major companies.  It is clear that European and African Americans think differently about science.  But why?

Table 1. Percent expressing a “great deal” of confidence in major US institutions, 2006-2010, by self-identified race


“p” denotes the probability that differences are due to chance sampling error, with p-values at 0.05 or below being statistically significant.


Explaining the racial gap in confidence

In a paper recently published in the Bulletin of Science, Technology & Society,[1] I explore five different explanations.  Some were drawn from scholarship in the “Public Understanding of Science” – an important subfield among scholars of science and society.  Others were based on current understanding of race and educational attainment in the United States and, in particular, the inadequate resources and limited effectiveness of schools serving predominately minority populations.  Still others assess the impact of cultural studies of race in the United States – focusing on the African American church, and the legacy of scientific racism in the United States.

Education.  For many years, a rather simplisitic model dominated the study of attitudes toward science.  According to this idea, individuals with better scientific education, would thereby have more scientific knowledge, and those who knew the most about science would have the greatest trust in scientific institutions and the greatest levesl of confidence in science as a means of solving important social problems.

Yet the weaknesses of this argument become apparent when considered in the context of race in the US.  My research shows that the “return on education” – the amount of traditional learning and retention that results from completing a particular course – is somewhat lower for blacks and whites, and African Americans take slightly fewer science classes than European Americans.  According to the traditional view – sometimes called the “deficit model” – all we need to do is create better learning environments and the racial gap would disappear.

Yes, we should improve the opportunities for all students to learn and  become excited by science.  But we should not expect that this will close the racial gap in confidence.  This is because it assumes that “to know it, is to love it.”  It ignores the possibility that as individuals – especially individuals from marginalized groups – learn more about an institution they may actually become less confident!

Indeed, the data show that whites with the greatest scientific knowledge are the most confident in science – but the same is not true of African Americans.  Uncritically extending a model developed for the majority culture does not help explain the racial gap in confidence.

Religion. In western history, advocates of scientific reason have often  been in conflict with religious traditionalists.  Yet this generalization belies the great diversity among faith traditions.  The Galileo controversy notwithstanding, religion/science tensions have generally been minimal among Catholics, and even less so among the so-called “Mainline” Protestant denominations.  In the last century, the greatest tensions have been evident between science and faith traditions that view the Bible as authoritative and inerrant.

Among all Whites, fewer than 30% believe that the Bible is the literal word of God.  Among Whites who are members of conservative faith traditions (Southern Baptists, and non-denominational evangelical churches, for example), that number rises above 55%.   In contrast, most African Americans are affiliated with conservative faith traditions and – not surprisingly – over 55% take a literalist view of scripture.

This partially explains the racial gap.  My analyses show that if Blacks and Whites had similar educational and religious affiliations, the original racial gap of 13 points would be halved.

Scientific racism and Tuskeegee. Finally, the paper explores the possibility that a legacy of scientific racism may loom large in African Americans’ cultural understanding of science.  Unfortunately, the 2006-2010 General Social Surveys do not contain either direct measures of relevant cultural knowledge or even plausible proxy measures.

However, a 1999 Henry J. Kaiser Family Foundation survey showed that 37% of African American respondents correctly identified that Tuskegee experiment as “a much-criticized government study of syphilis treatment involving African American men” (49% among those with some college education).

This may come as a surprise to university-based scholars, but at only 37% recognition, the Tuskegee experiment is not a pervasive element in African American culture (a conclusion at odds with those of McCallum and his colleagues, who analyzed a small convenience sample).

Nevertheless, these numbers could be more than sufficient to account for the unexplained seven point gap in confidence.  Unfortunately, it is impossible to empirically assess this possibility with available data as we are not aware of any study that asks both about confidence in science and knowledge of Tuskegee or other icons in the abuse of science as applied to Blacks.


Overall, the analyses reported the Bulletin of Science, Technology & Society represent an initial foray into understanding racial differences in confidence in science in the United States.  The models cannot be applied uncritically to other settings, but nevertheless may be suggestive of how alienation from science may develop in any society that has distinctive cultural minorities.

In addition, these models can be further specified by identifying more proximal causes.  For example, the analyses do not specify whether cultural communities that are skeptical of science are sustained by interpersonal talk that helps make sense of the scientific world, whether such talk can promote the spread of rumors, whether skepticism is influenced by exposure to particular media messages, or whether these attitudes are formed early in life through the internalization of political symbols (Sears et al. 1980).  These represent fertile areas for future inquiry.

[1] Plutzer, Eric. 2013.  “The Racial Gap in Confidence in Science: Explanations and Implications.”  Bulletin of Science, Technology & Society 33: 146-57.



A Journey of Curiosity and Contemplation to Research and Dissertation

By Dana Naughton, Ph.D.

Dana Naughton, Ph.D., Adult Education and Comparative and International Education, received an ARC research grant in Fall 2012 for her project entitled "Learning Through Adoption: The Intercountry Adoption Experiences of Canadian and Dutch Adopters of Children from the United States".

Several years before I entered the doctoral program in Adult Education and Comparative and International Education (CI ED) at Penn State, I worked as the Assistant Director of an international social service agency. The agency worked on micro and macro issues relating to family reunification across international borders, repatriation, international child-parental abduction, international adoption issues, and numerous other areas related to forced or voluntary migration. The work was unwaveringly fascinating and required collaboration with a global network of social workers, lawyers, and other professionals engaged in social welfare cases, policy, and laws across international borders.

While there, I became particularly intrigued by a subset of the cases the agency handled. These had to do with international adoptions (ICA; also known as intercountry adoption), a child welfare practice in which children of one country are legally transferred to the custody of citizens (adoptive parents) in another country. International adoption, while generally perceived as a (contested) child welfare solution, is very much an immigration process, and has been called “the quiet migration” (Weil, 1984, p. 276). One aspect of my work involved reviewing and approving ICA files, mostly adoptions by U.S. military families or expatriates living abroad whose adoption files needed to be reviewed by a U.S. agency. However, a small but steady stream of files that came across my desk were notable because they seemed to be going the wrong way. These adoptions involved U.S.-born children, and they were leaving the country to be adopted by families in Canada, the Netherlands, the United Kingdom, Switzerland, and other countries. At a time when U.S. citizens were adopting foreign-born children in record numbers, this adoption journey, I knew, did not fit the conventional paradigm of international adoption policy or practice.

Generally perceived as a “receiving” nation of international adoptees, the U.S., I came to learn, is, paradoxically a “sending” country, sought out by prospective adoptive parents across the world as a source country of adoptable children. These adoptions are called outgoing cases (United States Department of State [DOS], 2011) and in the last decade, families from a host of nations have adopted approximately 2,000 U.S. infants and young children (Selman, 2012). Most, though not all adoptees are Black, bi-racial or minority children. Similar in many ways to conventional paradigms of transracial and international adoption, these adoptions nonetheless fall challenge constructs of ICA practice in profound ways. For example; ICA is typically entwined in conflicting tropes of humanitarian rescue and post-colonial exploitation involving families from high-resource nations offering homes to children of low-resource nations who are abandoned because of extreme poverty or cultural-political forces that impact family size or constitution. The South-to-North migratory route frequently seen in ICA practice, in outgoing U.S. adoptions is revised. Although children may be placed “north” in Canada, their transnational journey is unquestionably from one high resource nation to another.

Birthparents in the contemporary ICA paradigm are highly marginalized. Most often they must be deceased (thus allowing the child to be a true orphan), unknown (for example as in China where it is illegal to abandon a child), or have permanently relinquished their child to public care. In contrast, outgoing U.S. adoptions are, in part, predicated on the U.S. birthparents’ right to choose their child’s adoptive parents. Moreover, U.S. birthparents could be in mediated (agency-facilitated) or direct contact with foreign prospective adoptive parents pre-and post-adoption—a practice not found in the contemporary paradigm. Additionally, child placement could occur within hours, days or weeks of a child’s birth – a timeline unheard of in conventional ICA practice. Finally, these adoptions occur within a complex racialized and socio-legal landscape. Researchers (Avitan, 2007; Dorow, 2006a, 2006b) suggest Black and bi-racial infants are available for adoption because White U.S. families bypass them in favor of less racially defined children (from China, Eastern Europe, or Russia) or foreign-born black children (from Ethiopia or Haiti) whose adoptions may be tethered to humanitarian notions of rescue.

Although I came to understand the (contentious) legal and policy issues that promoted or hindered these adoptions, the lived experience of these placements also intrigued me. How, I wondered, did European or Canadian parents help their Black or biracial child understand and create a racial identity or experience African American and U.S. life and culture? How did families tell their international adoption story to their child and others? Did they map it against familiar tropes of rescue or humanitarian assistance? How did they discuss with their child that his or her U.S. birth parents determined not just that another family was in the child’s best interest, but another culture and country as well? How did foreign parents prepare to adopt a U.S. child: What culturally related readings, training, resources, or activities did they draw upon before and after adoption, and what was the subsequent experience of the adoptive family as they engaged with their family, community and culture?

Despite my curiosity regarding these adoptions, my circumstances changed and I left the job, the region, and this line of work for a number of years. However, within months of entering my doctoral program at Penn State, I took the opportunity to explore dimensions of outgoing U.S. adoptions; at first, undertaking a pilot study with adoption professionals involved in the practice, and later, focusing my dissertation on the experiences of Canadian and Dutch families that have adopted children from the United States. Early on I realized that in spite of the vast canon of academic scholarship focused on policy, psychological adjustment, laws and other topics relating to international adoption and the U.S., the experience of foreign adopters of U.S.-born children was wholly absent from this empirical base. This gap in knowledge was important: It serves to inform academics, mental health practitioners, policymakers, families and communities, about child and parent experiences, education, and support when creating families though international adoption (Avitan, 2008; Balcom, 2011; Selinske, Naughton, Flanagan, Fry & Pickles, 2001; Wegar, 2008).

I addressed this gap in knowledge by conducting a field-based, narrative inquiry with adoptive parents in the two primary receiving countries of U.S. children: Canada and the Netherlands. Funding and support from Penn State’s Africana Research Center was instrumental to this field-based study.

My guiding hypothesis, generated from my pilot study findings, was that the adoption experience of these families differed substantively from that found in extant ICA literature. As a student of adult education and CI ED, I focused on the informal learning activities of adoptive parents and asked the following research questions:

(1) In what ways do personal experiences, knowledge, attitudes, or beliefs influence the decision of a Canadian or Dutch citizen to adopt a US child?

(2) How do Canadian or Dutch parents educate or prepare themselves – formally or informally – to adopt across racial, cultural, and international borders?

(3) How do accounts of Canadian and Dutch adopters of US children conform to or differ from discourses of ICA practice?

(4) In what ways has the adoption affected meanings of self, family, community, culture, country or worldview for the adoptive parents?

Research Design

The study followed a qualitative narrative tradition that focused on the participants’ account (story) of their lives, specifically the narrative of becoming a family through international adoption. I used a multi-perspective case study design with fieldwork in rural and urban communities in Canada and the Netherlands. I recruited families primarily through my former professional ties in international adoption work as an international adoption program coordinator, supervisor of outgoing adoption cases, and my network of contacts through my 20-year social work career. Twelve families in Canada and eight families in the Netherlands participated in the study. Eighteen families adopted Black, biracial or minority children, two families adopted White children. Ages at time of child placement ranged from approximately two days to three months.

Data collection for this study included: completion of a demographic questionnaire, participation in in-person and/or telephone interviews, and on-site observations of adoptive families in their environments (homes, neighborhoods, playgrounds, schools, etc.). Additional data sources included review of (a) adoptive family artifacts such as family pictures and memorabilia; (b) document analysis of ICA prospective parent training materials and curriculum and (c) review of Canadian and Dutch adoption laws, Hague Convention reports, relevant web documents and newspaper accounts of outgoing U.S. adoptions. With the consent of all participants, interviews were audiotaped and transcribed either by myself or a professional transcriptionist. I used NVivo 10 to assist with narrative and thematic analysis of the data.

Research Findings (the short version)

Participants’ narratives revealed several key findings. Prospective adoptive parents in Canada and the Netherlands shared similar psychosocial issues that led to them to form families through adoption. These included medical issues or being in later-age partnerships that precluded having biological children, coming from families in which siblings or other family members were adopted, or being in same-sex relationships and choosing adoption as a means to create a family. Socio-Cultural-historical factors affected choice as well. Acceptance of single parenting, social programs, reproductive education and options, and abortion have resulted in very few domestic infants being available for adoption, leaving prospective Dutch adopters to look to international adoption programs (von Hoof, 2010). Many Canadian families sought to adopt children from the U.S. because of comfort with U.S. culture, geography, and [English] language and a sense that adopting from the U.S. was similar to the Canadian private domestic adoption process. All but two of the twenty families interviewed expected to adopt a Black, biracial or minority child and all families in the study expected some pre- or post- contact with their child’s birth family.

Canadian and Dutch families substantially adapted and expanded their adoption-related learning beyond mandated or sponsored adoption agency, organization or state-based trainings as they prepared for, or subsequently adopted from, the United States. Canada and the Netherlands both require parent education when adopting (domestically or internationally) and families in both countries noted that their training overall was valuable and timely. Deficits noted in training included lack of information on adopting newborns, and lack of information on open adoption in situations of international adoption. Families in both countries engaged in significant informal learning activities to understand U.S. immigration laws; increase their knowledge of U.S. history - especially content around race relations and issues; gain facility in managing racialized encounters; negotiate adoptive-birth family relationships over time; understand racial and ethnic socialization processes and identity development of adopted and transracially adopted children; and, learn about and gain competency in hair, skin, diet and nutrition needs of their Black, biracial or minority children. Parents in Canada spoke of attending groups for mixed-race families, and/or calling upon the expertise of Black and biracial friends to help them anticipate and address the needs of their minority children. Families in the Netherlands socialized within a significant community of transracial adoptive families, most of whom had adopted Black and biracial children from the U.S. over the last 20 years.

The ICA experience of Canadian and Dutch adopters’ of children from the U.S. differed substantially from that found in the contemporary paradigm of intercountry adoption in process and in practice. Adoption applications were not handled by national authorities in the U.S. that matched foreign prospective adoptive families with available children (as is done for example in China, South Korea, India and other countries). Rather, foreign adopters completed adoption applications, met provincial or national Canadian or Dutch adoption requirements, created family portfolios and wrote letters to prospective U.S. birth parents in which they outlined their reasons for adopting and described the type of home and environment they would provide for a child. Adoption agencies in Canada with affiliations with U.S. adoption agencies or adoption service providers (usually adoption attorneys) forwarded these applications to the U.S. providers who in turn presented the family portfolios to U.S. birth parents as they made adoption plans for their child/children. For Dutch families the process was slightly different. For many of the adoptions in this study, Dutch families had to locate a U.S. adoption agency or provider themselves, a process known in the Netherlands as “Zelfendoers” [Do-It-Yourself] adoptions. This process has changed over the last several years and Dutch families now must work with Dutch agencies that have U.S. affiliates. The contemporary ICA paradigm follows a principle of subsidiarity in which a child’s family, community or country must first be considered before an international adoption placement is explored. However, U.S. adoption law privileges a birth parent’s right to choose an adoptive family and thus in U.S. outgoing adoptions, foreign families may be selected over U.S. families if the birth parent feels the foreign placement is in the child’s best interest and the birth parent’s state adoption court agrees to the placement. Another difference involved U.S. birth parents’ requests for contact with the prospective adoptive parents prior to, and after, a child’s birth. In several cases within this study, birth parents’ requested the prospective adoptive parents’ presence in the delivery room; in other cases, adoptive and birth parents have maintained contact long after the child’s birth and adoption. Some families in this study were in frequent contact with their child’s birth family through email, phone calls or even Facebook. One birth family had visited their child’s adoptive family in Canada and numerous families from both Canada and the Netherlands had visited birth families in the United States. These practices robustly challenge the contemporary ICA paradigm.

The presence or possibility of a level of open adoption in an intercountry adoption process was at times a mediating agent in parent learning, experience and meaning. For example, one adoptive mother spoke of her need to adeptly care for her child’s black-textured hair as she sought approbation from her daughter’s birth family who always commented on it during their U.S. visits. Another family studied the religious traditions of their child’s birth family to facilitate the child’s participation when visiting its’ U.S. family and several families named their children in consultation with the child’s birth parents. Several Dutch families assumed that their U.S.-born children might return to the U.S. visit their birth families, to attend university, or to take advantage of professional opportunities and sought opportunities to ensure that their child or children gained competency in English.

Finally, U.S. outgoing adoptions revealed a new model of intercountry adoption practice. This research indicated that outgoing U.S. adoptions reflect a new, hybrid form of ICA which calls for new content in training and preparation for prospective parents, new levels of pre-and post-adoption support for all members of the adoption triad, and provocative new considerations for intercountry adoption stakeholders. Specifically, pre-and post-adoption contact between birth and adoptive families requires extending ICA training to include content on establishing, maintaining or discontinuing relationships between birth and adoptive families. Several families in this study argued passionately for this need. One family, for example, described a difficult situation in which they had to tell their adopted child that their birth parent no longer wished for contact, while the adoptive parents of two children from different birth families had to negotiate situations where they had ongoing relationships with one child’s birth parents but not the other child’s birth family.

For ICA stakeholders such as policy makers, adoption service providers and adoption-triad members, the U.S. model moves forward an international adoption paradigm in which open adoption is both a possibility and basis for the ICA protocol and adoption experience. At its best, the model considers the communicative needs and potential healing force of moving ICA from a practice that marginalizes and obfuscates adoption circumstances to building on transparent relationships meant to be negotiated over distances and time.


Additional thoughts

Certainly both this study with its 30 participants and my earlier pilot study with ten adoption professionals from the U.S. and Canada are small in scale. Another limitation of the studies is that only U.S. outgoing adoptions in the context of the U.S., Canada and the Netherlands are considered. Nonetheless, data from the studies illuminates numerous facets of the lived experience of adopters as well as policy and practice issues that should be considered by adoption stakeholders. Research with both U.S. birth families and U.S. adoptees is critically needed, especially as this practice continues. Outgoing adoptions remain almost wholly invisible in the public and academic arenas, even as their numbers increase.


Avitan, G. (2007). Protecting our children or our pride? Regulating the intercountry adoption of American children. Cornell International Law Journal, 40, 489.

Balcom, K. (2011). The traffic in babies: Cross-border adoption and baby-selling between the United States and Canada, 1930-1972. Toronto: University of Toronto Press, Scholarly Publishing Division. Dubinsky, K. (2008). The fantasy of the global cabbage patch: Making sense of transnational adoption. Feminist Theory, 9(3), 339-345.

Dorow, S. (2006). Racialized choices: Chinese adoption and the `White noise” of Blackness. Critical Sociology, 32, 357-379.

Dorow, S. (2006b). Transnational adoption: A cultural economy of race, gender and kinship. New York, NY: NYU Press.

Selinske, J., Naughton, D., Flanagan, K., Fry, P., & Pickles, A. (2001). Ensuring the best interest of the child in intercountry adoption practice: case studies from the United Kingdom and the United States. Child Welfare, 80(5), 656–67.

Selman, P. (2012). The rise and fall of intercountry adoption in the 21st century. In J. Gibbons, K. Rotabi (Eds.), Intercountry adoption Policy practices and outcomes. (pp.7-28) London: Ashgate Publishing

US Department of State Bureau of Consular Affairs, (2011). The Hague Convention on Intercountry Adoption: A guide to outgoing cases from the United States. Retrieved from

Von Hooff, H. (2010). International adoption of children in the Netherlands. Court Appointed Advocates for Children (CASA), Judges’ Newsletter. Retrieved from

Wegar, K. (2006). Adoptive families in a diverse society. Piscataway, NJ: Rutgers University Press.

Weil, R. (1984). International adoption: The quiet migration. International Migration Review

Summer; 18(2):276-93



The Application of SOM-Artificial Neural Networks, PCA and GIS Technologies for the Characterization of Human Health Risk to Petrochemical Pollutants in the Niger Delta Region

By Richard Olawoyin, Ph.D.

Richard Olawoyin, Ph.D., Energy and Mineral Engineering, received an ARC research grant in Fall 2011 for his project entitled "The Application of SOM-Artificial Neural Networks, PCA and GIS Technologies for the Characterization of Human Health Risk to Petrochemical Pollutants in the Niger Delta".

1.0                   Introduction

The Niger Delta (Fig. 1) is located in the South-South region of Nigeria, western Africa with a total area of 7,722.04 square miles, and ranges between 4o151N and 4o501N and 5o251E and 7o371E (Powell et al., 1985). The population of the region is about 31 million (CRS, 2008), Annual mean temperature is estimated to be 80°F and annual average rainfall is 3000 mm (heavy rainfall due to proximity to the equator) (Akintola, 1982).The dynamism of marine sediment buildup and fluviatile activities during the upper Cretaceous, led to the formation of the Niger Delta, which is typified by widespread interconnectivity of, deltaic tributaries, mangrove swamps, flood plains, creeks, and coastal barrier islands. The soils in the region are of fluvial origin, characteristic of the back-swamps soils include peat covered water-logged weighty clay whereas clay and silty loamy soils are found in elevated areas (Rahaman, 1976). Samples were collected from five different regions in the area; Bonny, Eriemu, Odidi, Ugehlli and Warri (Fig. 2).


Fig. 1 Map of study sites showing the Niger Delta Area NDA geopolitical boundaries..jpg

Fig. 1: Map of study sites showing the Niger Delta Area (NDA) geopolitical boundaries.

Fig. 2 Sample locations, BN-Bonny ER-Eriemu, OD-Odidi, OG- Ughelli, WR-Warri River..jpg

Fig. 2: Sample locations, BN-Bonny; ER-Eriemu, OD-Odidi, OG- Ughelli, WR-Warri River.

Environmental media such as water, soil and sediments are susceptible to contaminations from various sources and substances, consequently leading to complexities in risk assessment decision making and management. Integrated quality assessment measures of these media using comprehensive procedures that entail the toxicity and toxicity identification, bioaccumulation, biomagnifications, persistence, chemistry, evidence of effects and physical property evaluation of these pollutants are important (Martín-Díaz et al.,2004; Chapman and Hollert, 2006; Chapman, 2007). The provision of significant integrated interpretations using high powered computing and artificial intelligence in assessing pollution levels is essential in setting priorities for mitigations and management measures that are needed for site restoration.

The anthropogenic impacts of industrial activities have been appraised by employing the artificial neural network self-organizing maps (ANN-SOM) learning algorithm for the identification and interpretation of the relationships between the measured variables and collected river sediment samples, improving the knowledge of contamination sources and potential harm to humans (Marengo et al., 2006). SOMs have been used in image classification (Lu, 1994), speech recognition (Kohonen, 1988), clustering of documents (Honkela et al., 1998). Comprehensive references to the SOM techniques can be found in Kohonen, 1985; Kohonen et al., 1995.

This research focus was on the valuable and suitable capability and application of the ANN-SOM technique for the classification, interpretation and visualization of water, soil and sediment data. This was vital in analyzing the contaminants concentrations, bioaccumulation, toxicity and also assess the quality of the sampled materials.

1.1                   Data Set

The datasets analyzed in this study include 14 physico-chemical variables (SO4, PO4 , Zn, Cd, Cr, Cu, Pb, Ni, Mn, Fe, the sum of 7 carcinogenic polycyclic aromatic hydrocarbons (PAHs), the sum of 10 non-carcinogenic PAHs, sum of total petroleum hydrocarbon , sum of benzene, toluene, ethylbenzene and xylene (BTEX) , and 2  toxicity parameters (pH and EC). The heavy metals were analyzed using extraction methods consistent with US EPA method 3050B. PAHs were treated using mass spectrometry detection (MSD) (González-Piñuela et al., 2006). Details on sample collection are presented in previous chapters and also described by Viguri et al., (2007); Olawoyin et al., (2012). The characteristics of the PAHs analyzed and the abbreviations are presented in Table 1.


Table 1: Priority PAHs -  Characteristics in Sampled Media



Benzene ring

a Carcinogenity

Mol. Wt. (g)

Solubility at 25°C (µg/L)






12.5-34.0 b











3.42 b



















































































BTEX - Benzene, Toulene, Ethylene and Xylene






Classification for carcinogens

2A Probable human carcinogens; 2B. Possibly carcinogenic to humans (Known or limited evidence in humans or adequate evidence in animals but insufficient evidence for humans); D. Non classifiable as carcinogenic to humans

a. Types of carcinogen from Watson and Dolislager; b in mg/L; c IARC, 1987



1.2                   Self-Organizing Map (SOM)

The Mathworks software (Matlab®) and SOM Toolbox version 2 was used for the SOM analysis (Vesanto et al., 1999). The input data was the measured variables and the values for all locations. The SOM tool was applied to project the input data (with multi-dimensions) into 2-dimesional lattice structure by going through a training phase and also preserving the topological features in the input data space. The methodology of the SOM involves the arrangement of neurons on a 2-D grid, where each neuron is associated with a prototype weight vector that carries the resemblance of the input data variables. The SOM used in this study was trained using the batch training algorithm as described in Kohonen (2001).

The methodology used in this study is presented in Fig. 3. SOM provides effective results which are easily visualized and interpreted from the generated component planes (CPs) and maps. In this study, based on the variables measured from the samples collected from the locations, samples in the same unit will show more similarities and represented closer on the map, while samples with different patterns are located far away from each other. Units with same weight vectors are represented on the same CP, therefore producing CP equal to the number of the data variables. Preliminary assessment of the CPs explains the pattern embedded in the data and how the values spread in the input space.

Fig. 3 Methodology of the study using SOM-ANN.jpg


Fig. 3:  Methodology of the study using SOM-ANN

2.0       Result and discussion

2.1       Samples Classification with SOM

Crude oil is a complex mixture of chemicals and other substances, primarily hydrocarbons and porphyry of metals and also organic substances. Sediment mineralogy and chemistry are essential for pollution assessment and evaluation. Sediments usually contain large amounts of fine grained clay minerals, which are known to transport pollutants by adsorption, and/or complex exchange at the clay-water interface. Hydrocarbon accumulations are known to be sediment dependents and the levels of contamination can be visualized using the SOM component planes (c-planes). The SOM component planes of the input variables for the sediment samples are illustrated in Fig. 4. The self-organizing map of each variable corresponds as presented in the figures to the map of the sample locations in Fig. 2. Each hexagonal unit on the map found at a particular location on the different component planes has the same location on the unit map. The values of the different components are represented using different colors with the scale on the right of each component map.

The unified distance matix (U-matrix) as presented in the SOM output provides the visualization of the relative distances between the neurons. Color differential is effectively used to show the calculated distance differences between adjacent neurons. A lighter color on the u-matrix indicates the closeness of the vectors in the input space while darker colors represent larger distances between vector values in the input space. The u-matrix also helps to identify clusters in the datasets. The SOM procedure using the u-matrix provides faster knowledge based interpretation of the input dataset distributions.

The c-planes of the input variables for the sediment as shown in Fig. 4 classified the different variables and due to the minimal effects of gas flaring in the areas on sediment chemical composition, low values of pH, NO3 and PO4 were recorded in the sampled area. There are increases in the area of contaminations with high pollutant volumes and especially hydrocarbon concentration (Rabalais et al., 1992).Towards the South Western (SW) parts of the study areas (Fig. 4), sediment contaminations were determined to be minimal as opposed to the northern areas with high concentrations of TPHs, PAHs and BTEX. PAHs and BTEX concentrations were observed to be spatially identical suggesting the possibility of a common source of contaminations in the area, the maximum values of PAHs and BTEX distribution in the sediments were at western points marked by extensive petrochemical activities, and these values decrease towards the South Eastern (SE) areas but increase in the opposite direction to all other parts. The TPHs concentrations are higher for the northern portion of the map with moderate to low values around the center. This phenomenon suggests that some level of remedial actions have been carried out in some residential areas in this region with high human population.

Fig. 4 c-planes of sediment variables classified using the SOM.jpg

Fig. 4: c-planes of sediment variables classified using the SOM

2.2       SOM interpretation

The analysis of the samples in the study with organic pollutant variables was also presented to the SOM. For the soil  and the ‘log’ normalization identified the best map quality with a 100-uint map size (i.e. 20 X 5) and with TE = 0.031, QE = 0.002 for the, and a 125-unit map size (i.e. 25 X 5) with TE = 0.000, QE = 0.668 (Table 4) for. While for the soil  the ‘range’ normalization gave the best map quality with a 100-uint map size (i.e. 20 X 5), TE = 0.000, QE = 0.136 (Table 5). The number of neurons (n = 100) are comparatively close to the number of samples (n = 98). Visualization of the c-planes for the soil  was helpful in the interpretation of the datasets. The soil showed similar distribution trends in the entire area for the individual carcinogenic PAHs. Elevated values of  representing high molecular weight (HMW) PAHs which are usually adsorbed on particles or present in oil droplets were found to be present in soils in the entire area except for the upper North Western (NW) part which showed lower values which could be potentially due to long proximity to the pollution sources closer to the southern parts on the study map.

Crude oil dispersed in the water bodies contaminates the water systems since it contains a mixture of a variety of substances such as high concentrations of organic compounds. The water then contains these pollutants in droplet or in dissolved phases. Due to the low solubility of aliphatic hydrocarbon compounds, they are usually present in water in the dissolved phase while aromatic hydrocarbons such as the PAHs are found in either of the phases depending on the molecular weight (MW) of the organic compound. BTEX are LMW aromatics and are moderately soluble in the water phase together with Nap. The HMW PAHs are mostly in the dispersed phase (OGP, 2005). The anomalous trends displayed in the SOM c-planes by water PAHs in the study areas, suggest possible oil contamination which could possibly have resulted from oil spills, deck wash, sabotaged pipelines and transportation related emissions. These trends also correlate with the pollutant concentrations and distributions in the sediment and soil samples with highest values at the southern part of the map and the concentration gradient is steep within these areas. BaP is the most toxic carcinogenic PAHs; it is contained in relatively higher levels throughout the southern parts posing significant carcinogenic risks to the residents of these areas.

2.3       SOM Interpretation for the Individual Sites

Analyses of soil PAHs for each of the sampled sites were also carried out using the input data for soilpresented to the SOM.  The map unit sizes for the four locations are; BN {= 6 X 4; 24 units; using ‘range’ normalization, TE = 0.040, QE = 0.077}, ER {= 5X 4; 20 units; using ‘range’ normalization, TE = 0.000, QE = 0.151}, OD {= 7 X 4; 28 units; using ‘log’ normalization, TE = 0.000, QE = 0.637}, OG {= 8 X 4; 32 units; using ‘log’ normalization, TE = 0.000, QE = 0.674}. The datasets were trained for individual sample locations as to have a detailed understanding of the local trend in the datasets. The BN location is characterized by high values of soil which corresponds to the location of the crude oil terminals towards the southern parts of the sampled area. The trend displayed by the soil at BN location indicates decreasing concentrations from pollutant source from the SE towards every other direction on the map. This trend is consistent with the combined soil carcinogenic PAHs analyses for all location. While for the ER location, the SOM visualization using the c-planes shows expected trends as majority of the petrochemical industries in the ER area are located between the center and towards the southern regions. The were distributed from the center towards the south of the map and these high values of in the soil of the area are imminent treats to the health and safety of the residents. The OD location is largely characterized by oil spills and waste discharges from petrochemical activities. The show pattern of higher contaminations towards the south which is consistent with other datasets analyzed. BaP, BkF and InP were determined to have the highest concentration values in the area which suggest that the risk of cancer induction for residents in this area especially those living in the southern parts is potentially high. This trend is identical to the trend observed from the OG SOM visualization. The major difference is that for the OG location, the c-plane for the total  showed uncontaminated areas on the North East (NE) area of the map against the North West (NW) uncontaminated sites established at the OD location.

3.0                   Summary

The physico-chemical properties (pH, TPH, BTEX, PAH, COD, SO4, PO4, NO3, and heavy metals) in the recipient environment of Bonny, Eriemu, Odidi and Ughelli (Warri) were assessed in sediments, soils and water. The SOM was used as a powerful visualization tool to identify trends in the dataset. Areas with high concentrations of pollutants were easily identified from the c-planes which revealed vital information for the interpretation of the results. Preliminary diagnosis of the quality of locational sediment, soil and water can be effectively carried out using the SOM algorithm to develop the c-planes. The physical, ecotoxicological and chemical features embedded in the datasets common to different locations sampled were easy to identify using the SOM c-planes and the most prevalent contaminants were identified for the different locations which would aid in remedial planning and decision making. From the result of the SOM dataset processing, it was observed that majority of the sites were contaminated with carcinogenic PAHs and carcinogenic heavy metals which are of concern due to the effects on human health. Composite risk index maps of the areas were also developed to validate the result obtained in this study (Figs. 5-8). Comprehensive remediation and mitigation plans are recommended for these areas. Furthermore, the provision of effective health care facilities that can evaluate the health conditions of the residents in the high contamination zones identified by the SOM and the provision of urgent care needed to those severely affected by the chronic exposure to these pollutants are also recommended. Therefore, these stations from the Niger Delta should be classified as highest priority sites regarding heavy metals and PAHs carcinogenic pollution when considering remediation decisions.


Fig. 5 Composite risk map of the BN Location, Niger Delta, Nigeria.jpg

Fig. 5: Composite risk map of the BN Location, Niger Delta, Nigeria



Fig. 6 Composite-Risk Map of the ER Location, Niger Delta, Nigeria.jpg

Fig. 6: Composite-Risk Map of the ER Location, Niger Delta, Nigeria

Fig. 7 Composite-Risk Map of the OD Location, Niger Delta, Nigeria.jpg

Fig. 7: Composite-Risk Map of the OD Location, Niger Delta, Nigeria



Fig. 8 Composite-Risk Map of the OG Location, Niger Delta, Nigeria.jpg

Fig. 8: Composite-Risk Map of the OG Location, Niger Delta, Nigeria



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The complete publications relating to this research work are available at the following references:

  • R. Olawoyin, A. Nieto, R. L. Grayson, F. Hardisty and S. Oyewole (2013). Application of Artificial Neural Network (ANN) – Self-Organizing Map (SOM) for the Categorization of Water, Soil and Sediment Quality in Petrochemical Regions. Expert Systems with Applications Vol. 40, Issue 9, July 2013, Pages 3634-3648
  • R. Olawoyin, (2013). Exploration of the Spatial-Composite Risk Index (CRI) for the Characterization of Toxicokinetics in Petrochemical active areas. Chemosphere (Accepted April 16, 2013)
  • R. Olawoyin; R. L. Grayson; O. T Okareh. (2012). Eco-toxicological and Epidemiological Assessment of Human Exposure to Potentially Petrogenic Polycyclic Aromatic Hydrocarbons in the Niger Delta, Nigeria. Toxicol. Environ. Health. Sci. Vol. 4(3), 173-185, 2012
  • R. Olawoyin, S. A. Oyewole, R. L. Grayson, (2012). Potential risk effect from elevated levels of soil heavy metals on human health in the Niger delta, Ecotoxicol. Environ. Saf., Vol. 85, 1 November 2012, Pages 120–130
  • R. Olawoyin R. L. Grayson and A. Nieto (2013) Characterization of Potentially Petrochemical Toxicants Using Chemometrics: A case study. Sci. Total Environ. STOTEN-D-13-00031 (under review)
  • R. Olawoyin, R. L. Grayson, O. T. Okareh, A. Nieto (2013). Characteristic Fingerprints of Polycyclic Aromatic Hydrocarbons and Total Petroleum Hydrocarbons in the Niger Delta, Nigeria, Environmental Earth Sciences ENGE-D-12-00620R1 (Under review)



Spring 2012

A Few Thoughts on Contested Histories…

By Crystal Sander, Ph.D.

Crystal Sanders, Ph.D., was a 2011-2012 ARC post-doctoral fellow whose dissertation is entitled "To Be Free of Fear: Black Women's Fight For Freedom Through the Child Development Group of Mississippi"

Students at the University of North Carolina recently protested the presence of a statue on campus honoring UNC alumni and students who fought and died in the Confederate Army. The statue, known as “Silent Sam,” was erected in 1913 during a time when slavery apologists attempted to whitewash history and suggest that the Civil War was about defending culture rather than about preserving slavery. During this time, Confederate monuments popped up on town squares and courthouse lawns across the South and even in the nation’s Capitol. In response, many African Americans—especially black clubwomen—rallied to protest these permanent tributes to the Confederacy because they understood that the statues obscured the harsh realities of slavery including rape and the separation of families. When the United Daughters of the Confederacy proposed a statue honoring Mammy, members of the National Association of Colored Women countered by purchasing and restoring Frederick Douglass’ home. In doing so, they matched an image of degradation with one of respectability.

While I am not pleased with a memorial to Confederate dead on public property, I do hope that the statue (and the protests it draws) forces faculty, students, and campus visitors to confront the legitimacy of the histories we tell. At the turn of the century, black Americans fought back erecting their own monuments and writing their own histories. It is my hope that the protests at UNC will lead to fruitful conversations and commemorations that pay tribute to the contributions people of color have made to the university.

The importance of speaking out and matching “story for story” became even more evident to me after reading The Help by Kathryn Stockett and watching the film of the same name. As a black women’s historian, I was saddened that a film about black domestics in Mississippi failed to adequately discuss the labor exploitation at the center of the arrangement (In 1960s Mississippi, black domestics were “lucky” to make $3.00 per day). I was also shocked that sexual harassment was never seriously mentioned seeing as how many domestic workers faced the constant threat of sexual assault. Winson Hudson, a Mississippi freedom fighter, penned a memoir in which she recounted her father borrowing money from a white doctor to buy farming supplies. When the doctor demanded repayment, Hudson’s father had no money on hand, yet he refused the doctor’s suggestion that his young black daughter go work in his house to repay the debt. Hudson recalled that her father refused that arrangement because “if you were by yourself and met a white man, you were almost sure to be raped.” Hudson’s father was the product of rape, so he took every precaution to protect her. He lost the family land, but protected his child. I share this story, not to suggest that all white men raped black women domestics in Mississippi, but to problematize Stockett’s narrative that does not really convey the vulnerability that black women endured in white homes.

Whether watching a Hollywood blockbuster or strolling through the campus of the first public university in the nation, I hope that my thoughts shared here will cause you to seek out historical accuracy in the images and stories put before you.