Charting achievements: a two-year retrospective of the society for environmental geochemistry and health (SEGH) and the evolving strategies.

Emerging from the shadow of the COVID-19 pandemic, it is time to ground ourselves and retrospectively assess the recent achievements of SEGH over the past years. This editorial serves as a comprehensive report on the progress made in comparison to the aspirations and goals set by the society's board in 2019 (Watts et al., Environ Geochem Health 42:343-347, 2019) (Fig. 1) and reflects on the state of the SEGH community as it reached its 50th anniversary at the close of 2021 (Watts et al. Environ Geochem Health 45:1165-1171, 2023). The focus lies on how the SEGH community navigated through the extraordinary challenges posed by the COVID-19 pandemic since early 2020, and to what extent the 2023 targets have been met.

Editorial: The society for environmental geochemistry and health (SEGH): 50 years and beyond.

When the SEGH international board released a short editorial paper back in 2019, we described an aim to increase the membership offering, whilst improving the diversity of input regionally, by scientific discipline and to ensure greater and more regular contact across the regions from 2020 onwards. Wider aspirations described in 2019 (Watts et al. 2019) are discussed within this short communication at the end of 2021 to evaluate progress made. In particular, how the SEGH community adapted to the unprecedented circumstances that have challenged each and every one of us throughout the COVID-19 pandemic since early 2020 and are likely to influence our activities for the foreseeable future.

Assessment of Pb contamination of soils, sediments and road dusts of the City of Lagos, Nigeria.

Lead (Pb) is of considerable concern among other heavy metals because of its toxic impact on the environment and human health. The geochemical nature and source-transport-fate of Pb in Nigeria's environmental media are relatively unknown. This study was undertaken to quantify and characterize Pb in soils, sediments and road dusts from Lagos, Nigeria. A total of forty-eight soil samples, seventeen sediment samples and thirteen roadside soils were collected from within Lagos metropolis. The samples were air-dried, screened, pulverized and sieved through 63-µm nylon mesh. Mineralogical constituent of samples were determined using X-ray diffraction. The sieved fractions and pulverized rock samples were digested and analyzed for elemental Pb components using inductively coupled plasma mass spectrometry (ICP-MS). The chemical fractionations of Pb in the samples were determined by sequential analysis. Lead isotope compositions of the samples were determined using quadrupole-based ICP-MS. Lead isotopic ratios and geo-accumulation indexes were used for discriminating and evaluating Pb sources. Quartz, microcline, K-feldspar, plagioclase and kaolinite were the preponderant minerals in powdered rocks, soils and sediments. The concentration (mg/kg) of elemental Pb in sediments and dusts for Lagos was 21-1963; 23-830 and 22-830, respectively. The plots (208Pb/207Pb)/(206Pb/207Pb) revealed that the Pb in the environmental media was derived from anthropogenic sources. The Pb isotopic ratios for soils, sediments and dusts were characterized by lower 208Pb/206Pb ratios, compared to bedrock. The Pb contents are held principally in the organic sulfide and reducible and carbonate phases. The Pb is held in very reactive geochemical phases, and these portend great risk to the environment and public health.

Evaluation of geochemical characteristics and health effects of some geophagic clays southern Nigeria.

The geochemical characteristics of geophagic clays from Calabar and Okon-Eket, southern Nigeria were evaluated to determine their quality and the possible health effects of their consumption. The study involved the measurement of the pH, electrical conductivity (EC) and total dissolved solids (TDS) of the slurried clay samples soaked in distilled water for 48 h using digital multi-parameters probe as well as the elemental and mineralogical analyses of twenty geophagic clay samples for elemental and mineralogical constituents using both the ICP-MS and XRD, respectively. Medical data were also mined from medical facilities within the area in addition to the administering of questionnaire to adults involved in the geophagic practices in order to determine their justification for the practice as well as their and clay preferences. Results of physicochemical measurement revealed that the pH range of the samples ranges from 3.9 to 6.9 and 6.5 to 7.0; EC 0.3-377.7 and 0.12-82.38 µS/cm; TDS 1.98-2,432.65 and 0.08-52.95 mg/L for consumed and non-consumed clay, respectively. The elemental analyses revealed that the concentration of some potential harmful elements, PHEs, exceeded the recommended dietary intake by humans. This is especially true for Cu (9.1-23 ppm), Pb (16.7-55.6 ppm), Zn (13-148 ppm), Ni (11.1-46.4 ppm), Co (1.8-21.7 ppm), Mn (16-338 ppm), As (BDL-15 ppm) and Cd (BDL-0.2 ppm). The predominant phases established in the clay samples are quartz and kaolinite, while the minor minerals were montmorillonite and muscovite in all the clay samples. Respondents revealed that capacity for relief from gastrointestinal problems believes in the curative power to cure skin infections and cultural reasons as main justification for the geophagic practices. This is, however, not in conformity with information gleaned from the medical records which still indicated that the prevalent diseases in the area still include gastrointestinal problems in addition to malaria, hypertension and cardiac failure with minor cases of respiratory tract infections. The high concentrations of the PHEs may be responsible for or contribute in part to the prevalence of hypertension, cardiac failures and gastrointestinal problems within the study areas. Though the kaolinite present in the geophagic clays makes them suitable for use as traditional antacids; however, the toxic trace element concentrations and significant quartz content will most likely mask the beneficial effects of such kaolinite.